US20050283150A1 - Surgical instruments with integrated electrocautery - Google Patents

Abstract

The present invention provides a series of devices for performing surgical procedures utilizing electrodes for performing electrocautery on a tissue of the body of a patient. The invention includes, in one aspect, a series of devices comprising surgical instruments providing at least one electrode for performing electrocautery, and, in another aspect, provides a method for cutting and cauterizing tissue with a surgical instrument. In yet another aspect, the invention involves a method for detecting the location of a bleeding vessel in a liquid-filled, visually monitored surgical field of a patient and for electrocauterizing the vessel to stop the bleeding before visualization of the surgical field is compromised. Preferred surgical instruments according to the invention also include operable components for forming a liquid cutting jet for cutting or ablating tissue of a patient and/or for providing a rotating, tissue contacting component for cutting, grinding, ablating, etc. tissue during a surgical procedure. Some surgical instruments, according to the invention, include one or more liquid conducting lumen therein for transporting and/or removing a liquid from a surgical operating field, which lumen, in some cases, are selectively coated with a layer of an electrically insulating material so that certain, selected, uncoated regions of an external surface of the lumen can act as an electrocautery electrode of the instrument.

Description

RELATED APPLICATIONS
• This application is a divisional of co-pending U.S. patent application Ser. No. 09/480,762, filed Jan. 10, 2000, entitled “Surgical Instruments with Integrated Electrocautery,” incorporated herein by reference.
FIELD OF THE INVENTION
• The invention relates to surgical instruments for performing a surgical procedure on a patient that include at least one integrated electrocautery electrode, and to methods for using the instruments in surgical procedures.
BACKGROUND OF THE INVENTION
• Traditionally, many surgical procedures have been performed on patients using open surgical methods that utilize relatively large incisions to expose a surgical field. Many traditional methods have also typically utilized surgical tools such as scalpels, scrapers, blunt dissectors, lasers, electrosurgical devices, etc., which can have poor tissue differentiating capability and which can sometimes cause inadvertent damage to tissue surrounding a surgical treatment site unless carefully utilized. Open surgery with such prior art surgical instruments often involves extensive trauma to the patient, with associated problems of long recovery periods and potential complications.
• There has been a trend in recent years to perform many surgical procedures using less invasive techniques by accessing surgical sites via small holes through the skin or through body orifices. These techniques are known as “minimally invasive surgery.” Minimally invasive surgical techniques commonly employed include endoscopic, laparoscopic, and arthroscopic surgical procedures. Minimally invasive surgical procedures are commonly preferred to open surgical procedures for many applications because the minimally invasive procedures induce less trauma to the patient during surgery and involve, in many cases, fewer potential complications and reduced recovery time.
• A variety of surgical instruments have been developed and utilized both for minimally invasive surgical procedures and for more traditional open surgical procedures. Frequently used instruments include blade and scalpel-type instruments, motorized rotary cutting and/or grinding instruments, laser instruments, liquid jet cutting instruments, and electrosurgical instruments. Typically, prior art instruments suffer from a variety of disadvantages. For example, typical prior art surgical instruments, especially those utilized for minimally invasive surgical procedures, have distal ends including a single component for performing a particular surgical function. Surgical instruments having distal ends including, for example, a rotating cutting or grinding head, a tissue-ablating laser, a liquid cutting jet, or an electrosurgical cutting jet are known in the art. Many of these prior art instruments suffer from a variety of disadvantages. For example, instruments having a distal end configured to perform only a cutting function must be removed from a surgical field of a patient and replaced with additional instruments if other surgical functions, such as grinding or electrocautery, are required. Similarly, instruments including, for example, a distal end having a grinding component or an electrosurgical or electrocautery component must be removed from a surgical site and exchanged with additional instrumentation for performing other functions, such as surgical cutting, etc. Such a removal and exchange of surgical instruments, especially when performing during minimally invasive surgical procedures, can be undesirable both from the standpoint of the speed and convenience, and also from the standpoint of the safety and effectiveness of the surgical instrument in performing complex surgical procedures requiring multiple tasks to be performed in the surgical operating field.
• For a variety of surgical procedures, including a variety of minimally invasive surgical procedures, it is often desirable to utilize a surgical instrument including a rotating component in the surgical field. Instruments providing rotating components may be advantageously utilized for surgical tasks such as grinding, polishing, drilling, cutting with rotating cutting blades, etc. Typical prior art surgical instruments providing rotating shafts for use in surgical procedures typically have employed electric motors to drive rotation of the shafts, or, alternatively, have employed pneumatically driven rotating turbine rotors. Such prior art instruments suffer from a variety of disadvantages. For example, instruments driven by electric motors often create rotation of grinding burrs, or other tissue contacting components connected to the rotating shaft, having relatively poor responsiveness of the rotational speed of the shaft to the resistance and torque applied to the tissue contacting component in the surgical field during operation. This poor responsiveness and feedback can, in some instances, lead to a variety of difficulties such as difficulty in maintaining contact of the rotating tissue contacting component, for example grinding burr, of the device with tissue in a particular desired location within a surgical field (e.g., due to skating or skipping of a grinding burr along the surface being ground), and also can lead to undesirable transmission of torque to a handle or other user interface of the surgical device, potentially causing a lack of operator control and unintended tissue damage.
• Pneumatically powered surgical devices providing rotating shafts typically provide better compensation of the rotational speed of the rotating shaft with applied load than electric motor powered instruments; however, pneumatically powered instruments require that surgical instruments be coupled to a source of highly pressurized gas during operation of the instruments, which can be inconvenient, expensive, or undesirable.
• U.S. Pat. No. 5,803,733 to Trott et al. describes a pneumatically powered surgical handpiece in which the pressurized fluid inlet is axially directed relative to the handpiece body. The handpiece includes a reaction-type turbine that is rotated by fluid flowing within a closed conduit. The handpiece utilizes a cantilevered turbine rotor, wherein the output shaft of the handpiece and the turbine rotor rotate about axes which are co-linear.
• Surgical instruments utilizing liquid-driven turbine rotors are also known. U.S. Pat. No. 4,631,052 to Kensey describes an elongated, flexible recanalization catheter that includes a working head which is adapted to be rotated by a turbine drive in operation. The turbine drive utilizes a liquid-driven turbine rotor comprising a reaction turbine whose rotational motion is imparted by pressure driven liquid flowing in a closed conduit. The turbine rotor and the rotating working head of the device are directly coupled together so that they rotate at essentially the same speed during operation. In addition, the rotor assembly is disposed at the distal end of the catheter and is essentially completely submerged in liquid during operation.
• U.S. Pat. No. 4,690,140 to Mecca describes a catheter for use in the removal of deposits lining the interior wall of a blood vessel that includes a rotating cutting device at its distal end. Rotational motion of the rotating cutting device is imparted by flow of a pressure-driven liquid. The cutting surfaces of the rotating cutting device and the turbine rotor comprise a single component rotating at essentially the same speed and about the same rotational axis. As with the '052 patent described above, the rotating cutting element of the '140 patent is disposed at the distal end of the catheter such that the turbine rotor causing rotation of the device is essentially completely submerged in liquid during operation.
• Surgical instruments providing electrosurgical cutting or cauterizing electrodes in combination with rotating surgical components or liquid perfusion and/or aspiration capabilities are also known.
• U.S. Pat. No. 5,527,331 to Kresch describes a tissue resection device for use in an organ inflated with a non-conductive fluid. The distal end of the device can include a perfusion lumen, a rotatable drive tube, and a drive tube aspiration lumen. A cutting tip can be mounted on the distal end of the drive tube. In some configurations, the cutting tip is further configured to act as an electrosurgical resection electrode.
• U.S. Pat. No. 5,941,876 to Nardella et al. describes an electrosurgical apparatus that includes a rotary, tissue affecting device, such as a rotating blade component, a rotating drill, or a rotating shaving/ablating device. The rotating device also serves as an active, energy delivering electrode for electrosurgery.
• U.S. Pat. No. 5,254,117 to Rigby et al. describes a multi-functional endoscopic probe apparatus capable of applying either a low or high frequency voltage to cut and cauterize tissue. The apparatus includes an elongated multi-lumen tube. The multi-lumen tube includes an irrigation lumen, a suction lumen, and a lumen providing passage for a slidably extendible and retractable electrosurgical cutting tip. The inner and outer surfaces of the multi-lumen tube can be coated with a layer of polyamide of uniform thickness for insulation. In some embodiments, the outer surface of the multi-lumen tube is further coated with a shrink-wrapped polytetrafluoroethylene insulating layer.
• U.S. Pat. No. 5,429,596 to Arias et al. describes an endoscopic electrosurgical suction-irrigation instrument with insertable probes and attachments. The instrument includes a fluid chamber that is sealed at its proximal end, includes slit valve for receiving the probes, and is connected at its distal end to a cannula through which the inserted probes extend. The fluid chamber can be selectively provided with suction and/or irrigation and includes an electrical contact for supplying voltage to an inserted electrosurgical probe. Depending on the probe configuration, suction and/or irrigation can be provided in an annular space between the probe and the cannula or through the probe.
• International Patent Application No. WO 97/24074 having inventors Isaacson et al. describes a hysteroscopic electrosurgical device. The device includes an electrosurgical probe, an irrigation channel, and an evacuation channel. In some configurations, a return electrode of the bipolar system provided by the instrument extends along an inner and/or outer surface of a sheath that is concentric about the positive electrode assembly.
• While the above mentioned surgical instruments represent, in some instances, improvements over many prior art surgical instruments for performing open and minimally invasive surgical procedures, there remains a need in the art to provide surgical instruments which have improved cutting, ablation, grinding, and/or tissue cauterizing capabilities, and which also have the ability to be utilized in a wide variety of open and/or minimally invasive surgical procedures to perform a variety of surgical functions. The present invention provides, in many embodiments, such improved surgical instruments, and further provides methods for their use in a variety of surgical procedures.
SUMMARY OF THE INVENTION
• The present invention provides a series of devices for performing surgical procedures utilizing electrodes for performing electrocautery on a tissue of the body of a patient. The invention includes, in one aspect, a series of devices comprising surgical instruments providing at least one electrode for performing electrocautery, and, in another aspect, provides a method for cutting and cauterizing tissue with a surgical instrument. In yet another aspect, the invention involves a method for detecting the location of a bleeding vessel in a liquid-filled, visually monitored surgical field of a patient and for electrocauterizing the vessel to stop the bleeding before visualization of the surgical field is compromised.
• In one aspect, the invention provides a series of surgical devices with integrated electrocautery. One device comprises a surgical instrument having a distal end adapted to perform a surgical procedure on a patient and a proximal end controllable by an operator. The instrument includes a pressure lumen having sufficient burst strength to conduct a high pressure liquid towards the distal end of the instrument. The pressure lumen includes at least one nozzle providing a jet opening. The nozzle is shaped to form a liquid cutting jet as a liquid at high pressure flows therethrough. The instrument further includes a rotatable shaft and a surgical component drivable by the shaft and constructed and arranged for contact with tissue in a surgical operating field. The instrument further includes at least one electrocautery electrode.
• Another device comprises a surgical instrument having a distal end adapted to perform a surgical procedure on a patient and a proximal end controllable by an operator. The instrument includes a rotatable shaft and a surgical component drivable by the shaft and constructed and arranged for contact with tissue in a surgical operating field. The instrument further includes a liquid jet-driven rotatable rotor drivingly coupled to the rotatable shaft, when the instrument is in operation, such that rotation of the liquid jet-driven rotatable rotor causes a corresponding rotation of the rotatable shaft. The instrument further includes at least one electrocautery electrode.
• Yet another device comprises a surgical instrument having a distal end adapted to perform a surgical procedure on a patient and a proximal end adapted to be controllable by an operator. The instrument includes a pressure lumen having sufficient burst strength to conduct a high pressure liquid towards the distal end of the instrument. The pressure lumen includes at least one nozzle providing a jet opening. The nozzle is shaped to form a liquid cutting jet as a liquid at high pressure flows therethrough. The instrument further includes an evacuation lumen that includes a jet-receiving opening locatable opposite the jet opening at a predetermined distance therefrom to receive the liquid cutting jet when the instrument is in operation. The instrument further includes a first electrode comprising at least a portion of an external surface of the pressure lumen, and a second electrode comprising at least a portion of the external surface of the evacuation lumen.
• Another device comprises a surgical instrument having a distal end adapted to perform a surgical procedure on a patient and a proximal end adapted to be controllable by an operator. The instrument includes a first lumen constructed of an electrically conducting material providing a first liquid passageway between the distal end and the proximal end of the instrument. The instrument includes a second lumen constructed of a conducting material providing a second liquid passageway between the distal end and the proximal end of the instrument. The first lumen is connectable in electrical communication with a first electrical potential. The first lumen has an external surface, at at least the distal end of the instrument, which is inserted into a surgical field of a patient when the instrument is utilized for a surgical procedure, that is coated with an essentially continuous layer of electrical insulation. The first lumen also includes an uninsulated region at its distal end that forms a first electrocautery electrode. The second lumen is connectable in electrical communication with a second electrical potential and has an external surface, at at least the distal end of the instrument, which is inserted into a surgical field of a patient when the instrument is utilized for a surgical procedure, that is electrically conductive and forms a second electrocautery electrode, except in a region at a distal end of the second lumen, which region at a distal end of the second lumen is coated with an essentially continuous layer of electrical insulation.
• In another aspect, a method for performing a surgical procedure is described. The method comprises inserting a surgical instrument into a surgical field of patient, creating a liquid cutting jet with the surgical instrument, cutting or ablating a selected tissue of the patient with the liquid cutting jet, applying an electrical signal of at least one electrode of the surgical instrument, and cauterizing a tissue of the patient.
• In yet another aspect, the invention provides a method for detecting the location of a bleeding vessel in a liquid-filled, visually monitored surgical field of a patient and for electrocauterizing the vessel to stop the bleeding before visualization of the surgical field is compromised. The method comprises inserting a surgical instrument into the surgical field of a patient, controllably evacuating a portion of the liquid from the surgical field with an evacuation lumen of the surgical instrument, visualizing a trail of blood originating at the bleeding vessel and flowing towards and into the evacuation lumen of the surgical instrument, moving the surgical instrument within the surgical field along the trail of blood towards the bleeding vessel, placing at least one electrode surface of the surgical instrument in proximity to the bleeding vessel, and applying an electrical signal to the electrode to electrocauterize the bleeding vessel to stop bleeding therefrom.
• Other advantages, novel features, and uses of the invention will become more apparent from the following detailed description of non-limiting embodiments of the invention when considered in conjunction with the accompanying drawings, which are schematic and which are not intended to be drawn to scale. In the figures, each identical, or substantially similar component that is illustrated in various figures is typically represented by a single numeral or notation. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention. In cases where the present specification and a document incorporated by reference include conflicting disclosure, the present specification shall control.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic, perspective illustration of a surgical liquid jet instrument providing a liquid cutting jet and a rotating burr at its distal end, with the body of the instrument disassembled to show the internal components thereof;
• FIG. 2A is a schematic, exploded, perspective illustration of a portion of the surgical instrument as inFIG. 1 showing the sheath and collar and components contained therein;
• FIG. 2B is a schematic, cross-sectional illustration of the distal end of the surgical instrument as inFIG. 2A showing the distal end of the rotatable shaft and the support element therefor;
• FIG. 2C is a schematic, cross-sectional illustration of the rotatable shaft and support element of the instrument as inFIG. 2B;
• FIG. 3 is a schematic, perspective illustration of the surgical instrument as inFIG. 1, excluding the body of the instrument, and as viewed from the proximal end of the instrument;
• FIG. 4 is a schematic, partially-cutaway, perspective illustration of the surgical instrument as inFIG. 1, wherein the sheath component has been rendered transparent;
• FIG. 5A is a schematic, perspective illustration of a portion of a surgical instrument showing an alternative embodiment for providing a distal end including a liquid cutting jet and a rotatable grinding burr;
• FIG. 5B is a schematic, perspective illustration of a portion of a surgical instrument showing another alternative embodiment for providing a distal end of a surgical instrument providing both a liquid cutting jet and a rotatable grinding burr;
• FIG. 6A is a partially-cutaway, schematic illustration of a portion of the distal end of a surgical liquid jet instrument for creating a liquid cutting jet in a surrounding liquid environment;
• FIG. 6B is partially-cutaway, schematic illustration of a portion of the distal end of a surgical liquid jet instrument for creating a liquid cutting jet in a liquid environment, where the evacuation lumen includes a constriction;
• FIG. 6C is a schematic illustration of a portion of the distal end of a surgical liquid jet instrument, illustrating various geometric relationships;
• FIG. 7A is a schematic, perspective illustration of a portion of a rotatable shaft including a grinding burr at its distal end, where the rotatable shaft includes a helically grooved channel disposed on at least a portion of the outer surface of the shaft;
• FIG. 7B is a schematic, perspective illustration of a portion of a rotatable shaft including a grinding burr, where the rotatable shaft includes an impeller thereon;
• FIG. 7C is a schematic, perspective illustration of a portion of a rotatable shaft with a grinding burr thereon and including a scoop shaped aperture in fluid communication with a channel defined by a hollow center of the shaft;
• FIG. 8A is a schematic, exploded, perspective illustration of the rotatable shaft drive mechanism of the instrument as inFIG. 1;
• FIG. 8B is a schematic, perspective illustration of a rotor assembly and rotatable shaft drive assembly of the rotatable shaft drive mechanism as inFIG. 8A;
• FIG. 8C is a partially-cutaway, schematic illustration of a portion of the rotatable shaft drive mechanism as inFIG. 8A showing the arrangement of the liquid jet nozzle, rotatable rotor, and liquid jet evacuation lumen;
• FIG. 8D is a schematic illustration of the liquid jet evacuation lumen and rotor assembly as inFIG. 8C, as viewed from above;
• FIG. 8E is a schematic, perspective illustration of a portion of the evacuation lumen as inFIG. 8D;
• FIG. 9A is a schematic illustration of a saw-tooth rotor;
• FIG. 9B is a schematic illustration of a portion of the saw-tooth rotor as inFIG. 9A, as viewed from above;
• FIG. 10A is a schematic, perspective illustration of a curved-vein rotor;
• FIG. 10B is a schematic illustration of several curved veins of the curved-veined rotor as inFIG. 10A;
• FIG. 11A is a schematic illustration of one embodiment of a configuration for providing evacuation for a surgical instrument;
• FIG. 11B is a schematic illustration of another embodiment for providing evacuation for a surgical instrument;
• FIG. 12 is a schematic, cross-sectional illustration of the liquid flow directing valve of the instrument as inFIG. 1;
• FIG. 13 is a schematic, cross-sectional illustration of the pressure-tight sealing component and spacer component of the liquid flow directing valve as inFIG. 12;
• FIG. 14A is a schematic illustration of a rotatably deployable surgical liquid jet instrument including integrated electrocautery electrodes;
• FIG. 14B is a schematic illustration of a portion of the surgical liquid jet instrument as inFIG. 14A showing more clearly the distal end of the instrument, when in the undeployed configuration;
• FIG. 14C is a schematic illustration of a portion of the liquid jet instrument as inFIG. 14A showing more clearly the distal end of the instrument, when in the deployed configuration;
• FIG. 14D is a partially-cutaway, schematic illustration of a portion of the surgical liquid jet instrument as inFIG. 14A;
• FIG. 14E is a partially-cutaway, schematic illustration of a portion of the surgical liquid jet instrument as inFIG. 14A;
• FIG. 14F is a schematic illustration of the actuating element of the surgical liquid jet instrument as inFIG. 14A;
• FIG. 15 is a series of schematic illustrations illustrating a method for forming a liquid jet nozzle region;
• FIG. 16A is a schematic, perspective illustration of a surgical instrument as inFIG. 1, but including integrated electrocautery electrodes; and
• FIG. 16B is a schematic, perspective illustration of a portion of the surgical instrument as inFIG. 16A, showing the configuration of the distal end of the instrument.
DETAILED DESCRIPTION
• The present invention provides a variety of liquid jet instruments useful in a variety of applications, many of which instruments are especially well suited for performing a variety of surgical procedures. The liquid jet instruments provided by the invention can be configured in a variety of different ways for use in various surgical operating fields. Furthermore, the liquid jets created by the instruments can be used for a wide variety of purposes; for example, as liquid cutting jets to cut, ablate, sculpt, debride, delaminate, etc. various tissues of a human or animal body. The term “tissue” as used herein refers broadly to a component of a human or animal body, such components including but not limited to muscle, skin, cartilage, tendon, bone, tooth, brain, cardiac tissue, vessels, internal organs, tissue of the eye, etc.
• The liquid jets may also be used to provide driving power to rotate rotatable shafts provided by instruments according to certain embodiments of the invention. The rotatable shafts of such instruments can be used for performing various surgical tasks, such as grinding, abrading, cutting, drilling, polishing, screwing, powering fastening tools, etc.
• Certain preferred surgical instruments, provided according to the invention, are configured as surgical handpieces having a proximal end with a grasping region, or body, shaped and configured to be comfortably held in the hand of an operator. The instruments also have a distal end that includes at least one component constructed and arranged for contact with tissue. As discussed in more detail below, in certain embodiments, the above-mentioned component can comprise the distal end of a rotatable shaft, which may include, for example, a grinding burr, a cutting blade, a drill, a screwdriver, or other component.
• In certain preferred embodiments, the instruments have a distal end that includes at least one nozzle for forming a liquid cutting jet. The distal end of the various inventive surgical instruments can be utilized, in certain preferred embodiments, to perform a surgical procedure on a patient. Although the surgical instruments described herein are shown as having a handpiece configuration, it should be understood that the invention is not strictly limited to surgical handpieces, and that the invention may also be practiced utilizing instruments including at least one liquid jet forming component but having a variety of alternative configurations and purposes. For example, instead of being configured as a surgical handpiece, the inventive surgical instruments could be configured for manipulation by machine control, such as a X/Y/Z positioning machine. Also, for embodiments involving instruments providing a liquid cutting jet at the distal end of the instrument, the liquid jet instrument can be used in a wide variety of surgical applications and utilize the high pressure liquid cutting jet to cut, drill, bore, perforate, strip, delaminate, liquefy, ablate, shape, form, etc. various tissues, organs, etc. of the body of a patient.
• The liquid jet surgical instruments provided by the invention preferably include at least one pressure lumen that has a distal end terminating in at least one nozzle that provides a liquid jet opening, and that has a proximal end that is connectable so as to be in fluid communication with a source of liquid under high pressure, supplied, for example, by a high pressure pump or high pressure liquid dispenser. The liquid jet nozzle is shaped to form a liquid jet as a liquid under high pressure flows through the nozzle as described in greater detail below. The liquid jet, in certain embodiments, is used to create a driving force for rotating a rotatable shaft of the instrument that can extend, in preferred embodiments, from the body of the surgical instrument towards the distal end of the instrument. In some embodiments, the instrument includes a pressure lumen that conducts a high pressure liquid toward the distal end of the instrument and that includes at least one nozzle that creates a liquid cutting jet as a high pressure liquid flows therethrough. The liquid cutting jet, for embodiments wherein the surgical instrument provides a liquid cutting jet at its distal end, can be used to cut, ablate, sculpt, trim, form, debride, etc., various tissues of a patient in surgical procedures.
• In some especially preferred embodiments, the surgical instruments provided by the invention include two pressure lumens, one for forming a liquid cutting jet at the distal end of the instrument and the other for forming at least one liquid jet utilized to drive the rotation of a rotatable shaft included in the surgical instrument. In some preferred embodiments, the liquid pressure supplied to the instrument by a high pressure pump or high pressure dispenser can be variably controllable by an operator of the instrument so that the cutting or ablating power of the liquid cutting jet, or the power supplied to rotate the rotatable shaft, is adjustable by the operator. This adjustability of the pressure can allow an operator to create a liquid cutting jet with the instrument that can differentiate between different types of tissue within a surgical operating field and/or can allow an operator to rotate a rotatable shaft of the instrument at varying rotational speeds with varying maximum achievable levels of torque according to the particular needs of the surgical procedure for which the distal end of the rotating shaft is being utilized.
• For example, for embodiments including a liquid cutting jet provided at the distal end of the instrument, a lower pressure can be utilized for cutting or ablating a soft tissue, such as fat, from a surface of a harder tissue, such as muscle or bone, where the liquid jet has sufficient strength to cut or ablate the soft tissue without damaging the underlying harder tissue. A higher pressure can then be selected that is sufficient to form a liquid cutting jet capable of cutting or ablating hard tissue, such as muscle or bone. For embodiments including liquid jet-driven rotatable shafts, a relatively low pressure liquid can be utilized for embodiments wherein a relatively low rotational speed and/or low torque is required, for example for embodiments having a cutting blade disposed at the distal end of the rotatable shaft that is used for cutting or trimming relatively soft tissue, and a high pressure liquid may be utilized for surgical procedures where higher rotational speeds and/or maximum torques are required, for example for embodiments where a grinding burr comprises, or is connectable to, the distal end of the rotatable shaft and is used, for example, for grinding hard tissue such as bone. In this way, the liquid jet surgical instruments provided by the invention, can, in many embodiments, provide highly selective and controllable tissue cutting, ablating, grinding, etc., in various surgical procedures. In addition, as discussed in more detail below, for embodiments involving surgical instruments providing both a liquid cutting jet and a rotatable shaft for performing surgical procedures, a liquid flow directing valve may be included within the body of the surgical instrument. The valve can function to direct a high pressure liquid to the pressure lumen within the surgical instrument that is in fluid communication with the liquid cutting jet forming nozzle at the distal end of the instrument, to the pressure lumen that is in fluid communication with the nozzle forming a liquid jet configured to drive rotation of the rotatable shaft, or to both simultaneously.
• Preferred embodiments of the inventive surgical instruments that are configured to provide a liquid cutting jet at their distal end also include a liquid jet target or dissipater that is locatable opposite the jet opening orifice in the nozzle from which the liquid cutting jet is emitted (hereinafter referred to the “liquid jet opening” or “jet opening”) at a predetermined distance from the liquid jet opening in order to receive and/or dissipate energy of a liquid cutting jet, when the instrument is in operation. Embodiments including a target or dissipater are preferred because the target/dissipater prevents the liquid cutting jet from being misdirected during use and potentially causing damage to unintended tissue sites in the surgical operating field. The target/dissipater enables the instrument to provide a predetermined liquid cutting jet length defined by the predetermined distance between the liquid jet opening in the nozzle and the surface of the target/dissipater upon which the cutting jet impinges. With such embodiments, the liquid cutting jet can be utilized for performing surgical cutting or ablating of tissue with a reduced danger of causing unintended collateral damage to tissue lying beyond the target/dissipater in the surgical operating field.
• In some embodiments, the target/dissipater can be simply a solid surface capable of dissipating the energy of a liquid cutting jet by transforming the liquid jet into a harmless spray. In more preferred embodiments, however, the target is defined by a jet-receiving opening included in an evacuation lumen that forms part of the surgical instrument. In the preferred embodiments of instruments including an evacuation lumen having a jet-receiving opening, in addition to providing a defined liquid jet length (defined by the predetermined distance between the liquid jet opening and the jet-receiving opening) and preventing unintended damage as discussed above, the evacuation lumen can also be utilized for removing liquid, ablated tissue, and debris from the surgical field. In some embodiments of surgical jet instruments having an evacuation lumen for receiving a liquid cutting jet according to the invention, an external source of suction, for example a vacuum pump or aspirator, can be provided in fluid communication with a proximal end of the evacuation lumen in order to provide the suction driving force required for evacuating material from the surgical field via the jet-receiving opening. In some preferred embodiments, however, the invention provides surgical instruments having an evacuation lumen that is shaped and positionable relative to the jet nozzle forming the liquid cutting jet (as will become apparent to those of ordinary skill in the art from the detailed description below) to enable evacuation of essentially all of the liquid comprising the liquid cutting jet as well as ablated tissue and debris from the surgical site without requiring an external source of suction. In some preferred embodiments, the evacuating force created by the liquid cutting jet being directed into the evacuation lumen is sufficient to evacuate material from the operating site to a drainage reservoir located at the proximal end of the evacuation lumen or an evacuation conduit connected to the proximal end of the evacuation lumen. In such embodiments, the liquid cutting jet and the evacuation lumen together act as an eductor pump, which utilizes the momentum and kinetic energy of the moving fluid of the liquid cutting jet to create an evacuating force capable of driving liquid, ablated material, and debris through the evacuation lumen and away from the surgical site.
• As discussed in detail below, the invention teaches that the effectiveness of evacuation of material through the evacuation lumen without the use of an external source of suction (i.e., via eductor pump action) can be improved, in some instances, by designing certain inventive instruments to provide particular geometrical relationships between the components for forming the liquid cutting jet and the components for receiving the liquid cutting jet, relating, for example, the size of the jet-receiving opening in the evacuation lumen to the predetermined distance between the jet-receiving opening and the jet opening for forming the liquid cutting jet with the nozzle. Also, as taught by the invention, interrelated with the above-mentioned geometrical relationships for providing effective eductor pump action is the design of the liquid jet nozzle and the shape of the jet-receiving opening in the distal end of the evacuation lumen.
• The liquid jet surgical instruments provided according to the invention may be utilized for performing surgical procedures, involving liquid cutting jets and/or rotatable tissue contacting surgical components, in a wide variety of surgical fields, including those comprising both liquid-filled and gaseous environments. As described below, certain of the inventive surgical instruments providing liquid cutting jets at their distal ends are especially well suited for performing surgical procedures in a liquid-filled surgical environment, where the distal end of the instrument, including, in some embodiments, the nozzle for forming the liquid cutting jet and the jet-receiving opening, are submerged in a liquid when the instrument is in operation. Such devices can be configured as surgical handpieces for use, for example, in endoscopic, arthroscopic, or other surgical procedures.
• As is described herein, and in much greater detail in commonly owned co-pending U.S. patent application Ser. No. 09/313,679, entitled FLUID JET SURGICAL INSTRUMENTS, incorporated herein by reference, the inventive surgical liquid jet instruments that provide a liquid cutting jet at their distal end, can be configured to effectively remove material from the surgical site and transport the material through an evacuation lumen without the need for an external source of suction for a wide variety of angular orientations between the central region of the liquid cutting jet and the longitudinal axis of the evacuation lumen. The term “central region of the liquid jet” as used herein refers to a region defining a geometric center of the liquid jet. This region is typically an essentially cylindrical region of the liquid jet confined within a cylinder whose outer surfaces are shaped and whose perimeter is defined by the inner circumference of the liquid jet opening in the nozzle, which circumference is projected from the liquid jet opening to the jet-receiving opening along an axis that is co-linear with the longitudinal axis of the jet nozzle. The “longitudinal axis” of the jet nozzle, as will be described in more detail below, is defined by the axial center line of the nozzle region of the pressure lumen. The “longitudinal axis” of the evacuation lumen refers to an axis defining the geometric center of the evacuation lumen in a region that is proximal to the jet-receiving opening. As used herein in the context of describing geometric relationships between longitudinal axes of various components, the term “co-linear” refers to components whose longitudinal axes are superimposed on essentially the same line and space. The term “parallel” when used in the same context refers to longitudinal axes that are not necessarily co-linear, but that are oriented in an essentially identical direction in space. Accordingly, surgical instruments provided according to certain embodiments of the invention enable effective evacuation of material and debris from the surgical site via a liquid cutting jet evacuation lumen, without the need for an external source of vacuum connected in fluid communication with such lumen, for a wide variety of liquid cutting jet angular configurations, including instruments providing liquid cutting jets that are directed axially, transversely, or at any angle between 0 and 180° with respect to a longitudinal axis defining the proximal end or body of the surgical instrument.
• For embodiments involving surgical instruments including an evacuation lumen for receiving a liquid cutting jet, plugging of the evacuation lumen can be prevented by constructing the evacuation lumen receiving the liquid cutting jet to have a region that is within and/or downstream of the jet-receiving opening that is designed to be able to macerate at least a portion of the tissue trained by the liquid jet into a plurality of particles when the instrument is in operation. The term “macerate” as used herein refers to a disaggregation of entrained material, for example an entrained tissue, by a liquid within the evacuation lumen undergoing intensely turbulent flow that creates a region of extremely high fluid shear and impacting forces capable of partitioning the material into particles having a size small enough to pass through the evacuation lumen without plugging the lumen. In preferred embodiments, the evacuation lumen is able to macerate a substantial fraction of the tissue entrained into a plurality of essentially microscopic particles. “Microscopic” as used herein refers to particles having a dimension too small to be visualized unaided by the human eye.
• Prevention of blow-by (defined as a portion of a liquid cutting jet or high velocity fluid entrained by the liquid cutting jet having a cross-sectional area, at the plane of the jet-receiving opening, that is larger than the cross-sectional area of the jet-receiving opening so that at least a portion of the liquid cutting jet or high velocity fluid misses or “blows by” the jet-receiving opening) can be accomplished by providing a surgical jet instrument having a distal end configured so that, when in operation, the liquid cutting jet and the high velocity fluid entrained by the liquid cutting jet occupies a substantial fraction of the cross-sectional area of the jet-receiving opening, but does not occupy a region larger than the cross-sectional area of the jet-receiving opening. As discussed in more detail below, this “substantial fraction” refers to at least 50%, but less than 100% of the cross-sectional area of the jet-receiving opening being occupied by an entrainment region created by the liquid cutting jet.
• As discussed above, certain embodiments of the surgical instruments provided according to the invention include a rotatable shaft, which, in some preferred embodiments, extends from the body of the instrument, or from the proximal end of the instrument, towards the distal end of the instrument. The rotatable shafts provided according to the invention can have distal ends comprising, or reversibly connectable to, a surgical component that is constructed and arranged for contact with tissue in a surgical operating field. The “distal end” of the rotating shaft as used herein refers to a portion of the rotating shaft located at the distal end of the instrument and within a surgical operating field when the instrument is in operation. It should be emphasized that the distal end of the rotatable shaft can include, in some embodiments, regions proximal to the extreme distal tip of the rotatable shaft that are still within the surgical operating field when the instrument is in operation.
• Components constructed and arranged for contact with tissue can be components that are comprised by the distal end of the rotatable shaft itself or, alternatively, can be components that are removably attachable/connectable to the distal end of the rotatable shaft. Such components may, as apparent to those of ordinary skill in the art, be provided in a wide variety of forms for performing a wide variety of functions useful in various surgical procedures. For example, in some embodiments, the component can be constructed and arranged to cut, grind, ablate, shape, drill, bore, pulverize, polish, liquefy, screw, etc., a tissue within the operating field. In addition, as described in more detail below, the rotatable shaft can be permanently, or semi-permanently, contained within the surgical instrument or, alternatively and more preferably, can be configured to be removable and exchangeable with other rotatable shafts, for example those having different components at their distal ends for performing different surgical functions. It is also contemplated that the rotatable shaft can be configured within the surgical instrument so that its distal end, including the component constructed and arranged for contact with tissue, is selectively retractable so that, under control of an operator, the distal end of the rotatable shaft may be selectively deployed into the surgical operating field for performing a surgical procedure and, when the procedure is completed, retracted into the instrument and away from the surgical field. Such a retractable configuration can be especially useful for instruments including both a rotatable shaft and a liquid cutting jet at the distal end of the instrument, wherein during a surgical procedure requiring the rotatable shaft, the shaft may be deployed into the surgical operating field, but during a procedure requiring use of only the liquid cutting jet, the rotatable shaft may be withdrawn from the surgical field, if desired.
• For instruments provided according to the invention including a rotatable shaft therein, the proximal end of the rotatable shaft is typically disposed within a body or at a user-controllable proximal end of the instrument. The proximal end of the shaft is drivingly coupled to a mechanism that is constructed and arranged to impart a rotating motion to the rotatable shaft. The term “drivingly coupled” as used herein refers to the shaft being interconnected with a drive mechanism such that motion of a component of the drive mechanism imparts rotational motion to the rotatable shaft. Such coupling can be accomplished, as would be apparent to those of ordinary skill in the art, by a variety of means such as, but not limited to, gear drives, belt drives, chain drives, friction drives, etc. The drive mechanism utilized to rotate the rotatable shaft within the instrument can comprise one or more of a variety of drive mechanisms including, but not limited to, electric motors, pneumatic turbines, etc., as apparent to those of ordinary skill in the art. However, in preferred embodiments, the invention utilizes an inventive liquid jet-driven rotatable rotor, preferably positioned within the body or at the proximal end of the instrument, to impart rotational motion to the rotatable shaft.
• Preferred embodiments of the liquid jet-driven rotatable rotor mechanism provided according to the invention utilize a pressure lumen, having a liquid jet forming nozzle at a distal end thereof, to direct a liquid jet so that it impacts an impacting surface on the rotatable rotor, thus driving rotation of the rotor, which, in turn, creates a corresponding rotation of the rotatable shaft that is drivingly coupled thereto. Unlike typical prior art fluid driven turbine mechanisms, the preferred shaft-drive mechanism provided according to the invention does not utilize an expanding gas or, as is the case with typical prior art liquid-driven turbines, confine the rotor and liquid flow path within in an enclosed duct or channel such that the rotor is essentially completely submerged in a liquid during its rotation. In such typical prior art “reaction” turbines, the liquid driving the rotor undergoes a substantial change in hydrostatic pressure while in contact with the driving surface of the rotor. In contrast, the liquid jet-driven rotatable rotor mechanism provided according to the invention preferably maintains the liquid jet-driven rotor within a surrounding gaseous environment while it is being rotatably driven by a liquid jet during operation, so that essentially no part of the rotor is submerged in liquid during operation. In other words, the liquid that is in contact with the rotatable rotor, according to the invention, is essentially limited to a region of the liquid jet contacting a jet impacting surface of the rotatable rotor. As described in more detail below, the mechanism functions by directing an essentially collimated liquid jet, from a jet opening in the nozzle of the pressure lumen, across a gas filled gap so that it impacts a surface of the rotor, imparting rotational motion thereto. While in the embodiments illustrated below a single liquid jet is directed so that it impacts an impacting surface on a rotatable rotor, thus driving rotation of the rotor, in other embodiments, multiple nozzles in the pressure lumen and/or multiple pressure lumen may be utilized to direct multiple liquid jets at one or more impacting surfaces of a single or multiple rotatable rotors within the instrument for driving the rotatable shaft, or, alternatively, for driving multiple rotatable shafts.
• In some preferred embodiments, the rotatable rotor is contained within a housing within the body of the instrument, which housing is evacuated to remove any accumulated liquid therein so that the rotatable rotor remains essentially unsubmerged in a surrounding liquid during operation. In especially preferred embodiments, described in more detail below, an evacuation lumen including a jet-receiving opening therein is positioned opposite the jet opening in the nozzle of the rotor-driving pressure lumen and downstream of the impacting surface of the rotatable rotor so that it receives and evacuates the liquid comprising the rotor-driving liquid jet. Similarly to the evacuation lumen utilized for receiving and evacuating liquid cutting jets described above, the evacuation lumen utilized for receiving and evacuating the rotor-driving liquid jet can, in some embodiments, be placed in fluid communication with an external source of suction or can, in more preferred embodiments, be configured to enable evacuation of essentially all of the liquid comprising the liquid rotor-driving jet without the need for an external source of suction connected thereto. Except as specifically described below, the configurations useful for the nozzle and evacuation lumen utilized in the inventive rotor-driving mechanism can be similar to those described below for forming and evacuating a liquid cutting jet.
• The preferred liquid jet-driven rotatable rotor described above utilizes primarily the impulse force resulting from a change in the momentum of the liquid jet, upon contact with an impacting surface of the rotor, to impart rotational motion to the rotor. In the inventive configuration, liquid leaves the nozzle of the pressure lumen as a jet having a free-surface, at the jet opening, in the surrounding gaseous environment. In such configuration, essentially the entire pressure drop of the liquid comprising the jet to atmospheric pressure takes place within the nozzle. By contrast, typical prior art fluid-driven drive mechanisms for use in surgical devices employ a turbine-driving fluid stream that is confined within a channel and utilize the acceleration of the fluid, while it is in contact with a turbine or rotor, characterized by a change in the hydrostatic pressure of the fluid while in contact with the turbine/rotor, to drive rotation of the turbine/rotor. The present inventors have determined that the preferred liquid jet-driven rotor mechanism provided according to the invention can, under certain conditions, provide improved efficiency of operation as well as improved torque vs. load characteristics, as compared with prior art mechanisms.
• Also, as described in more detail below, for many embodiments of the invention, it is often desirable to provide a mechanism for drivingly coupling a liquid jet-driven rotor to a rotatable shaft of a surgical instrument so that the rotational speed of the rotatable shaft is different from that of the rotational speed of the liquid jet-driven rotor. Such rotational speed-changing drive mechanisms are well know to those of ordinary skill in the art. In the context of the present invention, a preferred drive coupling mechanism utilizes a gear reduction drive. The gear reduction drives utilized according to the invention can be configured in a variety of forms as apparent to those of ordinary skill in the art, including, but not limited to, screws and worm gears, helical gears, spur gears, etc. Some preferred embodiments of the invention utilize a gear reduction drive coupling mechanism providing a rotational speed of the rotatable shaft that is a defined fraction of the rotational speed of the liquid jet-driven rotatable rotor. By utilizing such a gear reduction mechanism, the maximum torque obtainable at the distal end of the rotatable shaft for rotating a tissue contacting surgical component, such as a grinding burr, can be larger, by a factor of the degree of gear reduction, than the torque that would be obtainable utilizing a direct drive coupling mechanism with the same diameter rotatable rotor. This can enable the use of a smaller diameter rotatable rotor for obtaining a particular value of maximum torque under maximum load conditions (i.e., when the rotatable shaft is completely stalled so that its rotational speed is essentially zero). As will be discussed in more detail below, a particularly advantageous configuration of a driving mechanism for providing rotary motion to the rotatable shaft, according to the invention, utilizes a liquid jet-driven rotatable rotor that rotates about an axis of rotation that is essentially perpendicular to the axis of rotation of the rotatable shaft (defined by the longitudinal axis of the shaft) of the surgical instrument. This configuration provides a compact and effective means for coupling rotation of the rotatable rotor to the rotatable shaft through the gear reduction mechanism.
• The inventive surgical instruments will now be described in more detail in the context of several specific embodiments illustrated in the appended figures. It is to be understood that the embodiments described are for illustrative purposes only and that the novel features of the invention, as described in the appended claims can be practiced in other ways or utilized for instruments having other configurations, as apparent to those of ordinary skill in the art.
• FIG. 1 shows one embodiment of asurgical instrument100, provided according to the invention.Surgical instrument100 illustrated is configured as a surgical handpiece having aproximal end102 including abody104 having graspingregions106 configured for placement in the hand of an operator of the instrument.Body104 as shown can be formed, in preferred embodiments, from a rigid plastic material, and is preferably configured so that it can be separated into adjoining sections so that components disposed within the body may be accessible. In the illustrated embodiment,body104 comprises twohalves108,110 joined together by means ofscrews112 which mate with threadedbores114. It should be understood that a variety of other means of joining the sections of the housing together can be utilized, as apparent to those of ordinary skill in the art, for example, such means including but not limited to, ultrasound welding, snap fitting, solvent welding, etc.
• Surgical instrument100 has adistal end116 including apressure lumen118 and anevacuation lumen120.Distal end116 ofinstrument100 further includes a rotatable grindingburr122 disposed at the distal end of a rotatable shaft124 (seen more clearly inFIG. 2A). “Distal end” when used herein in the context of a region of a surgical instrument refers to a30 portion of a surgical instrument that is adapted to perform a surgical procedure on a patient and which is inserted into a surgical field during operation of the instrument. Thedistal end116 ofinstrument100 can, in some embodiments, comprise only the distal ends126,128 ofpressure lumen118 andevacuation lumen120 respectively as well as thedistal end130 of rotatable shaft124 (seeFIG. 2A) including grindingburr122. In other embodiments,distal end116 ofinstrument100 can also include components proximal to the distal ends of the pressure lumen, evacuation lumen, and rotatable shaft that are also inserted into a surgical operating field of a patient during operation of the instrument. In addition, in other embodiments, not shown, the instrument may provide only a rotatable shaft and may not include a pressure lumen and an evacuation lumen at the distal end of the instrument. In yet other embodiments, the instrument may not include a rotatable shaft and grinding burr as shown but may instead include only a pressure lumen at the distal end of the instrument or, in other embodiments, a pressure lumen together with a target or evacuation lumen positioned opposite the pressure lumen to receive a liquid cutting jet.
• In the illustrated embodiment,surgical instrument100 further includes asheath132 which at least partially surroundspressure lumen118,evacuation lumen120, androtatable shaft124. As explained in more detail below,sheath132 aids in supplying support for the lumen to assist in maintaining and/or establishing a desired geometric configuration betweenpressure lumen118 andevacuation lumen120 to prevent relative motion of the lumen and misdirection of a liquid cutting jet. In addition,sheath132 can be used for providing support and evacuation todistal end130 ofrotatable shaft124. As discussed in more detail below in the context ofFIGS. 2A-2C, removably coupled todistal end116 andsheath132 isburr tip support136 including asnap tab138 which fits into snap-lock slot140 onsheath132 to enable removable coupling thereto.Burr tip support136 also serves to provide a bearing surface fordistal end130 ofrotatable shaft124, as well as to provide support to pressurelumen118 andevacuation lumen120.
• Proximal end142 ofsheath132 is sealingly coupled to the distal end ofcollar144, whose function will be more thoroughly explained in the context ofFIG. 4 below.Collar144 includes aseating flange146 which is held in place byslots148 inbody104 when the instrument is assembled.Flange146 also includes projectingridge150 which mounts within a complementary groove withinbody104, in order to preventcollar144 from rotating during operation of the instrument.
• Contained withinbody104 ofinstrument100 is drivingmechanism152 configured for drivingrotatable shaft124. The specific details of the structure and operation of drivingmechanism152 are described in more detail below in the context ofFIGS. 8A-8E.Drive mechanism152 includes a liquid jet-driven rotor and gear reduction mechanism, shown and described in more detail below, enclosed in a three-part rotor housing154 held together byscrew fasteners156 and comprising an upperrotor housing cap158, arotor housing block160, and a rotorhousing bottom component162. High pressure liquid is supplied to drivemechanism152 via rotordrive pressure lumen164.Rotor housing154 is evacuated of liquid via rotorjet evacuation lumen166, rotor housingblock evacuation conduit168, and rotor housingbottom evacuation conduit170. Also visible inFIG. 1 isrotor bearing172. Bearings for use in the current invention for rotatably mounting a rotor or components ofdrive mechanism152 coupled torotatable shaft124 can comprise any suitable type of bearing known in the art, for example ball bearings, journal bearings, or hydrodynamic bearings. In the illustrated embodiment, the bearings comprise ball bearings.
• Also contained withinbody104 is rotatableshaft evacuation conduit174 for providing evacuation tosheath132 surrounding the rotatable shaft and disposed in proximity to grindingburr122.Body104 also includes an evacuationconduit connecting block176, which serves to couple the evacuation conduits (168,170, and174) andevacuation lumen120 and166 toevacuation tubing178 exiting the proximal end of the instrument.Connecting block176 can include any one of a variety of low pressure tubing connectors known to those of ordinary skill in the art, such as barbed connectors, Leur-lock connectors, press-fit connections, etc.
• In the illustrated embodiment, including both apressure lumen118 for forming a liquid cutting jet at thedistal end116 of the instrument and apressure lumen164 for forming a liquid jet that provides rotational driving force to a rotatable shaft, a liquidflow directing valve180 may be included. The structure and function of liquidflow directing valve180 is described in greater detail below in the context ofFIG. 12. Liquidflow directing valve180 has aninlet182 coupled to high pressureliquid supply conduit184 by means of a manually tightenable highpressure tubing coupling186.Valve180 also includes afirst outlet188 that is coupled viahigh pressure connector190 topressure lumen118 supplying high pressure liquid tonozzle192 disposed atdistal end116 of the instrument for forming a liquid cutting jet.Valve180 also includes asecond outlet194 coupled viahigh pressure connector196 topressure lumen164 supplying high pressure liquid to rotatableshaft drive mechanism152. Liquidflow directing valve180 can be manually adjusted by an operator, via sliding motion ofknobs197, which are coupled to a shaft198 (seeFIG. 12), to enable liquid supplied viaconduit184 to be directed to eitherpressure lumen118 orpressure lumen164, depending upon the position ofknobs197, or to be directed to both pressure lumens simultaneously.
• High pressure connectors186,190, and196 may comprise any type of suitable high pressure connection known to those of ordinary skill in the art that is capable of withstanding, for example, pressures in excess of 1,000 psig, and preferably is capable of withstanding pressures up to at least about 50,000 psig. Such connectors may comprise welded/brazed fittings, flanged fittings, swaged fittings, etc., as apparent to those of ordinary skill in the art. In a preferred embodiment, as illustrated, the high pressure fittings utilized include highly compressed elastomeric O-rings and are configured as described in commonly owned U.S. Pat. No. 5,713,878, incorporated herein by reference.
• FIG. 2A is an exploded perspective view of the portions ofsurgical instrument100 disposed distal tobody104. As illustrated inFIG. 2A,rotatable shaft124,pressure lumen118 andevacuation lumen120 are shown removed fromsheath132 for clarity.Pressure lumen118 andevacuation lumen120 are preferably constructed from a surgical grade stainless steel, however, in alternative embodiments, either or both of the lumen may be constructed from other suitable materials, for example certain polymeric materials, as apparent to those of ordinary skill in the art. Regardless of the specific material from which the pressure lumen is constructed, pressure lumen118 (as well aspressure lumen164 supplying drive mechanism152) must have sufficient burst strength to enable the lumen to conduct a high pressure liquid to the nozzle, forexample nozzle192, at the distal end of the pressure lumen in order to form a liquid jet. The burst strength of the pressure lumen utilized in the surgical instrument should be selected to meet and preferably exceed the highest contemplated pressure required for use in the specific surgical procedure to be performed. Typically,surgical instrument100 will operate at liquid pressures of between about 500 psig and about 50,000 psig, depending on the intended material to be cut and/or ablated and/or the required rotational speed and maximum torque of the rotatable shaft. Those of ordinary skill in the art will readily be able to select appropriate materials for forming the pressure lumen of the instrument and the evacuation lumen for particular surgical requirements based on the functional requirements of each described herein.
• Also illustrated inFIG. 2A is a preferred configuration for supportingrotatable shaft124 andlumens118 and120 withinsheath132.Rotatable shaft124 includes acoupling region200, having a reduced cross-sectional area and a non-circular cross sectional shape, disposed at its proximal end.Coupling region200, as described in more detail below, enablesrotatable shaft124 to be coupled in driving engagement withshaft drive mechanism152. Supporting thedistal end130 ofrotatable shaft124 isburr tip support136. Shown in more detail inFIG. 2B andFIG. 2C,burr tip support136, when assembled, provides a centralshaft bearing region202 surrounding aregion204 ofrotatable shaft124 having a circular cross sectional shape and a reduced cross sectional dimension when compared to thecentral region205 ofrotatable shaft124.Region204 is surrounded by shaftdistal bearing region202 ofburr tip support136 and rotates therewithin, when the instrument is in operation. Longitudinal movement ofrotatable shaft124 with respect toburr tip support136 andsheath132 is prevented byshaft bearing flange206 andbearing lip208 ofrotatable shaft124.
• FIG. 2C shows a cross-sectional view ofburr tip support136 as viewed from the distal end of the instrument.Burr tip support136 includes anupper support member210 and alower support member212, which are separable one from the other when disassembled fromsheath132, and which, when coupled together, formshaft bearing channel202. As shown inFIG. 2C,burr tip support136 further includes anevacuation lumen slot214 and apressure lumen slot216 for holding and supportingevacuation lumen120 andpressure lumen118 withinsheath132 respectively, when the instrument is assembled for use.Burr tip support136 also includesevacuation channel slots218 which, when the device is assembled, provide fluid communication, between the inside ofsheath132 and the region distal toburr tip support136 within the surgical field, for evacuating tissue and debris surrounding grindingburr122 from the surgical field and away from the patient. As discussed in more detail below, this evacuation may be provided by means of a source of external suction coupled in fluid communication with the proximal end ofsheath132 or, in alternative embodiments, may be generated by the rotation ofrotatable shaft124 itself.
• Burr tip support136 enables easy disassembly and exchange ofrotatable shaft124 and grindingburr122. In this manner, a variety of grinding burrs, or other components for performing a surgical function on tissue of a patient can be interchanged during the course of a procedure or between surgical procedures. Replacement or exchange of a rotatable shaft/burr element can be performed as follows. While in an assembled configuration, for example as shown inFIG. 1, the user depressessnap tab138 on thespring flange region220 ofburr tip support136 and slides the burr tip support and rotatable shaft frombore222 ofsheath132.Pressure lumen118 andevacuation lumen120 are rigidly connected at their proximal ends withinbody104 ofinstrument100 and remain within the sheath during removal of the rotatable shaft and burr tip support. While removingburr tip support136 fromsheath132, the distal ends ofpressure lumen118 and120 slide throughpressure lumen slot216, including anozzle slot224 therein, andevacuation lumen slot214. Upon removal ofburr tip support136 androtatable shaft124,upper support member210 andlower support member212 can be separated,rotatable shaft124 can be exchanged with another rotatable shaft having, for example, a different component at a distal end thereof, the upper support and lower support can be reassembled, and the burr tip support/rotatable shaft unit can be re-inserted intobore222 ofsheath132 untilsnap tab138 snaps intosnap lock slot140 of the sheath, thus completing the exchange process. Those of ordinary skill in the art will readily envision a variety of alternative means for providing exchangeability ofrotatable shaft124 ofinstrument100, all of which are deemed to be within the scope of the present invention.
• Upon assembly,burr tip support136, in addition to providing a distal bearing forrotatable shaft124, also supplies support forpressure lumen118 andevacuation lumen120 to assist in maintaining and/or establishing a desired geometric configuration between the pressure lumen and the evacuation lumen wheninstrument100 is in operation. In preferred embodiments,pressure lumen118 andevacuation lumen120 are supported byburr tip support136, when the instrument is assembled, so that the distal ends of the lumen are sufficiently stiff to prevent deflection of the lumen, by, for example, contact with surfaces within the surgical operating space, which deflection could potentially lead to misdirection of the liquid cutting jet formed bynozzle192 as high pressure liquid flows therethrough so that the cutting jet is no longer incident upon jet-receivingopening193 inevacuation lumen120, thus potentially causing unintended tissue damage to the patient.
• FIG. 3 is a perspective view showingsurgical instrument100 as viewed from a proximal end thereof.FIG. 3 illustrates the assembled surgical instrument except excludingbody104 to show the internal components with greater clarity. The particular view illustrated shows more clearly the back view ofshaft drive mechanism152 showing shaft drive bearing230 as well as the locations for attachment to rotor drivejet evacuation lumen166, rotor housingblock evacuation conduit168, and rotor housingbottom evacuation conduit170. Also shown more clearly ishigh pressure conduit184 andevacuation conduits178. High pressureliquid supply conduit184 must have a burst strength capable of withstanding the highest liquid pressures contemplated for usinginstrument100 for a particular surgical application. In some embodiments, high pressureliquid supply conduit184 comprises a burst-resistant stainless steel hypotube constructed to withstand at least 50,000 psig. In some embodiments, the hypotube may be helically coiled to improve the flexibility and maneuverability ofsurgical instrument100. In preferred embodiments, especially those including integrated electrocautery as discussed below, high pressureliquid supply conduit184 is comprised of an electrically insulating material such as a Kevlar®-reinforced nylon tube. The liquid contained in evacuation conduits178 (as well asevacuation conduits168,170, and174 within the body of the instrument) is under relatively low pressure and, accordingly, the evacuation conduits may be constructed, in preferred embodiments, of a low cost flexible material, for example, polymeric tubing such as polyvinyl chloride (PVC), silicone, polyethylene, rubber, etc., tubing.Evacuation lumen120 and at least the distal end (i.e. that contained withinhousing154 and surrounding the rotor, as shown inFIGS. 8C-8E below) ofevacuation lumen166 are preferably constructed of a rigid material, such as stainless steel. In preferred embodiments,evacuation conduits178 should have a minimum internal cross-sectional area that equals or exceeds the maximum internal cross-sectional area of the evacuation lumens and conduits withinbody104 ofinstrument100 to which the evacuation conduits are coupled in fluid communication.
• FIG. 4 is a perspective illustration showing surgical instrument I00 as viewed from itsdistal end116. InFIG. 4,surgical instrument100 is shown withoutsheath132 orbody104 to more clearly illustrate the internal configuration of thecollar144 providing fluid communication betweensheath132 andshaft evacuation conduit174, as well as to more clearly illustration of thedistal side153 of rotatableshaft drive unit152.
• Collar144 is shown partially cutaway inFIG. 4.Collar144 can be comprised of a metal, such as surgical stainless steel, or in more preferred embodiments, can be comprised of a rigid plastic, such as polycarbonate, nylon, acetal polymers, etc., as apparent to those of ordinary skill in the art.Collar144 has adistal end145 with a centrally disposed bore240 therethrough surroundingpressure lumen118,evacuation lumen120 androtatable shaft124.Bore240 is sized and configured so thatproximal end142 ofsheath132 can be press-fit therein to form a continuous, leak-tight path for fluid communication betweenshaft evacuation conduit174 andevacuation channel slots218 ofburr tip support136, when the instrument is assembled as shown inFIGS. 1 and 2A-2C. In the illustrated embodiment, evacuation is supplied to the distal end of the instrument surrounding grindingburr122 by couplingshaft evacuation conduit174 in fluid communication with a source of external suction, such as a suction pump or aspirator. As described below, in alternative embodiments,rotatable shaft124 can be configured such that rotation of the shaft is able to impart a driving force for removing material from the region surrounding the grinding burr without requiringconduit174 to be attached to the source of external suction.
• Collar144 further includes a centrally disposedcavity242 therein having adistal region244, which is conically tapered, and aproximal region246, which is essentially cylindrical in shape.Distal end248 ofrotor housing base162 is shaped to mate with inner sealing surfaces250 ofcavity242 incollar144, to create a vacuum-tight seal betweensurface252 of the distal end of the bearing block andinner sealing surface250 of the collar.
• Distal end248 ofrotor housing base162 includesgrooves254,256 machined therein, which grooves form channels for passage ofpressure lumen118 andevacuation lumen120 respectively. In order to prevent leakage of evacuated fluid and a loss of suction throughgrooves254 and256 during operation of the device, a bead ofsealant258 can be used to surround the lumen and create a vacuum-tight seal withinner sealing surface250 ofcollar144, upon assembly of the device. Such sealant can be comprised of a polymeric foam or RTV sealant, as would be apparent to those of ordinary skill in the art.
• Proximal end248 ofrotor housing base162 further includes asheath evacuation channel260 machined therein for providing a fluid flow path for transport of fluid and debris betweencavity262, comprising a sheath evacuation region, andevacuation conduit174. During operation of the device, when a suction is applied toevacuation conduit174, liquid and debris will flow intosheath132 viaevacuation channel slots218 ofburr tip support136, then throughbore240 ofcollar144 intosheath evacuation cavity262, throughsheath evacuation channel260, and finally throughevacuation conduit174 for removal from the instrument.
• Also shown inFIG. 4 are rotor jet pressurelumen mounting blocks264,266 which are utilized to mount rotordrive pressure lumen164 torotor housing block160 via, for example, screws268. As described in more detail below, the rotor jet pressure lumen mounting blocks enabled precise alignment and direction of the liquid jet formed by the nozzle ofpressure lumen164 onto an impacting surface of a rotor utilized for drivingrotatable shaft124, when the device is in operation.
• FIG. 5A illustrates an alternative embodiment for configuring the distal end of a surgical instrument providing both a liquid cutting jet and a rotational grinding burr and also more clearly illustrates a preferred configuration for providing a liquid cutting jet nozzle and evacuation lumen distal end.Instrument272 includes aproximal end274 and adistal end276. Unlike the previously illustrated embodiment,instrument272 includes asheath278 surrounding onlyrotatable shaft280 including, at its distal end, a grindingburr282.Surgical instrument272 further includes apressure lumen284 and anevacuation lumen286, both of which are disposed external tosheath278.
• For embodiments of the invention utilizing rotating shafts including grinding burrs at their distal ends, a wide variety of grinding burrs can be utilized depending on the needs of the particular surgical application, as would be apparent to those of ordinary skill in the art. For example, fluted burrs and diamond burrs of various shapes and sizes can be used. For example, spherical, cylindrical, oval, flat, pear or egg shaped burrs may be utilized of various sizes for particular surgical applications. Typical burr sizes for use, for example, in bone grinding for arthroscopic procedures, can have an outer diameter ranging from about 2 mm to about 6 mm with the number of flutes, for fluted burrs, ranging from about 2 to about 20. In one particular example, involving the use of a grinding burr for bone grinding in arthroscopic procedures, a 5 mm outer diameter spherical, fluted burr having eight flutes is utilized.
• In the configuration shown inFIG. 5A,distal tips288 and290 ofpressure lumen284 andevacuation lumen286 respectively are disposed distally to grindingburr282. In another embodiment shown inFIG. 5B,distal tips288 and290 may, alternatively, be disposed proximal to grindingburr282.
• Also shown inFIG. 5A is a preferred arrangement for formingnozzle192 in a pressure lumen for creating a liquid jet, as well as a preferred configuration for thedistal end290 of the evacuation lumen of the surgical instrument configured to receive a liquid cutting jet.Pressure lumen284, which is substantially identical in configuration topressure lumen118 discussed above, comprises a tubular conduit having anecked region292 of theconduit defining nozzle192, which necked region has an internal cross-sectional area that is less than an internal cross-sectional area of the tubular conduit outside of and proximal tonecked region292. The distal end ofpressure lumen284 is further configured to enablejet opening294 to direct aliquid cutting jet296 in a direction essentially transverse to thelongitudinal axis298 ofpressure lumen284. Specifically,nozzle region292 is bent with respect tolongitudinal axis298 ofpressure lumen284 outside ofjet nozzle region292, so thatjet opening294 emits aliquid jet296 whose central region is directed along anaxis300 that is essentially perpendicular tolongitudinal axis298. In alternative embodiments, the angle formed betweenjet axis300 andlongitudinal axis298 can be any angle between about 0° and about 90° (as shown).
• Nozzles provided according to the invention, both for forming liquid cutting jets and for forming liquid jets to drive rotational components of the instruments (as described in more detail below) preferably have a relatively large nozzle length to internal diameter ratio. The nozzles for use in inventive surgical instruments, both for forming liquid cutting jets and for driving rotational motion of a rotatable shaft, preferably have a region having a minimum internal diameter, which region has a length that exceeds its minimum internal diameter by at least a factor of about 2, more preferably by a factor of about 4, and even more preferably by at least a factor of about 6. In other embodiments, the region has a length that exceeds its minimum internal diameter by at least a factor of about 10. As will be discussed in more detail below, the greater the ratio of the length to minimum internal diameter of the nozzle region, the more narrowly focused and collimated will be the liquid jet that is emitted from the jet opening of the nozzle. For reasons described in more detail below, highly collimated liquid jets are preferred both for forming liquid cutting jets at the distal end of the inventive surgical instruments and for driving rotational motion of rotatable rotors and shafts provided by the inventive surgical instruments. However, in general, nozzles with ratios of length to minimum internal diameter that are very high, for example greater than about 10, tend to create a very high pressure drop through the nozzle during use without significantly improving the degree of collimation of the jet and, therefore, are less preferred for use in the inventive surgical instruments than nozzles having a ratio of length to minimum internal diameter of an intermediate value, for example about 6.
• The present invention provides surgical liquid jet instruments which are specifically designed and constructed for use in a particular surgical environment. Specifically, certain embodiments of the invention provide surgical liquid jet instrument designs that are tailored to provide highly desirable liquid jet cutting characteristics in surgical operating environments where the liquid jet is submerged in a liquid environment when the instrument is in operation. More specifically, the invention provides, in such embodiments, surgical liquid jet instruments including pressure lumen and evacuation lumen that are shaped, and positioned relative to each other, to establish certain predetermined geometric relationships between the jet forming components and jet-receiving components that are specifically selected to provide the desired performance characteristics of the instrument in a liquid surgical environment.
• Reference is made inFIG. 6A for describing the operation and design characteristics of preferred devices for use in forming a liquid cutting jet that is submerged in a surrounding liquid-containing surgical environment.FIG. 6A shows a partially cutaway view of the distal ends ofpressure lumen118 andevacuation lumen120, which can form part of a surgical instrument, for example such as that shown previously inFIG. 1. Prior to operation, the distal ends ofpressure lumen118 andevacuation lumen120 would be inserted into the operating field and at least partially submersed in a liquid300 therein so that atleast nozzle192 and jet-receivingopening193 are completely surrounded byliquid300. When the instrument is in operation, liquid under high pressure is delivered viapressure lumen118 tonozzle192, causing jet opening294 to create aliquid cutting jet296 as the high pressure liquid streams therethrough. As mentioned previously, it is preferred that thejet296 is substantially collimated as it exitsjet opening294. The more collimated a liquid jet, the less the liquid jet will diverge or disperse as it traverses the gap between jet opening294 and jet-receivingopening193. Thus, a highly collimated jet will have a cross-sectional shape and area at the jet-receivingopening193 that is substantially similar to the cross-sectional shape and area of the liquid jet atjet opening294.
• In general, the pressure of the high pressure liquid supplied tonozzle192 for forming theliquid cutting jet296 depends on the particular design ofnozzle192 and the hardness/toughness of tissue or material to be cut or ablated. Typically, the liquid at high pressure is supplied tojet opening192 at a pressure of at least 500 psig, in other embodiments at a pressure of at least about 5,000 psig, and still other embodiments at a pressure of at least about 15,000 psig, and still other embodiments at a pressure of at least 30,000 psig, and in yet still other embodiments at a pressure of at least about 50,000 psig. Also as discussed previously, for embodiments where a collimated jet is desired,nozzle192 preferably has a length to minimum internal diameter ratio of at least about four, more preferably at least about six, and in other embodiments at least about ten.Jet opening294 typically has a circular cross-sectional area, but may, in other embodiments, have other cross-sectional shapes, such as rectangular, oval, slit-like, etc., for forming jets having different shapes for specific desired purposes. In preferred embodiments, jet opening294 has an internal diameter of between about 0.001 and about 0.02 inches, more preferably between about 0.003 and about 0.01 inches, and most preferably about 0.005 inches.
• Liquid cutting jet296, which is collimated as it exitsjet opening294, tends to create a visible,opaque entrainment region302 surroundingliquid cutting jet296.Entrainment region302 is comprised of rapidly moving liquid, which is entrained and driven by the kinetic energy ofliquid cutting jet296.Liquid cutting jet296, as it rapidly moves throughliquid environment300, also tends to create a zone of low pressure, which is essentially coextensive withentrainment region302. In typical embodiments involving high pressure liquids and rapidly moving liquid jets, the pressure in entrainment region/low pressure zone302 will be lower than the vapor pressure of the surrounding liquid inliquid environment300, thus causing cavitation of the liquid inentrainment region302 and a resulting formation of an abundance of extremely small gas bubbles304 within the liquid in theentrainment region302, making the region visually opaque.
• As discussed previously, it is desired, in preferred embodiments, for safety and performance that the instrument be designed to reduce, and preferably eliminate, undesirable effects, such as blow-by of the liquid jet, plugging of the jet-receiving opening and the evacuation lumen, and inefficient tissue/debris entrainment and removal. Also, as previously mentioned, in preferred embodiments, it is desirable that ablated tissue and debris be evacuated from the surgical site through the evacuation lumen, without the need for a source of external suction to be applied to the proximal end of the evacuation lumen. In order to provide the above-mentioned characteristics, the inventive surgical instruments for use in a liquid environment can include an evacuation lumen having specifically selected predetermined shapes and configurations, which is positionable relative to the jet opening at a specific predetermined distance. Specifically, in preferred embodiments, jet-receivingopening193 is positioned, when the instrument is in operation,opposite jet opening294, at a predetermined distance f therefrom, and provided in anozzle192 having a length to minimum diameter ratio so that essentially all of the fluid inliquid cutting jet296 enters jet-receivingopening193. As discussed above,liquid cutting jet296 will tend to createentrainment region302 surrounding theliquid cutting jet296 when the instrument is in operation.Entrainment region302 will typically be symmetrically deposed aroundliquid cutting jet296 and will tend to diverge in a direction from jet opening294 to jet-receivingopening193. In typical embodiments wherejet opening294 is circular in shape,entrainment region302 will have a truncated cone shape, having a truncated apex atjet opening294 and a base defined as a cross section of the cone at the plane of jet-receivingopening193. In preferred embodiments, the base ofentrainment region302 occupies between about 50% and about 100% of the cross-sectional area of jet-receivingopening193 when the instrument is in operation, more preferably the entrainment region occupies at least about 75%, more preferably still at least about 90%, and most preferably at least about 95% of the cross-sectional area of jet-receivingopening193 when the instrument is in operation.
• As shown inFIG. 6C, the cross-sectional area of the jet-receivingopening193 required to ensure that theentrainment region302 occupies the desired relative fraction of the cross-sectional area of the jet-receivingopening193, as discussed above, is functionally related to the chosen predetermined distance l between thejet opening294 and the jet-receivingopening193 and the degree of divergence characterizing the entrainment zone (represented by angle φ inFIG. 6C). Specifically, the desired cross-sectional radius b of the base of theentrainment region302 at the jet-receivingopening193 is related to predetermined distance l and the degree of divergence of the entrainment region by b=l tan φ. Predetermined distance l is typically selected based on the desired use of the surgical instrument, dictating a required fluid path cutting/ablating length. Based upon this desired predetermined distance l, the required size of the jet-receivingopening193 is typically determined experimentally by submersing thepressure lumen118 andnozzle192 in aliquid environment300, forming aliquid cutting jet296 by supplying a liquid to thenozzle192 at a desired predetermined pressure, and visually observing the size of theentrainment region302 or cavitation cone created around theliquid cutting jet296, and estimating angle φ from the observations.
• As mentioned above, the predetermined separation distance l between thejet opening294 and the jet-receivingopening193 depends upon the requirements of the particular surgical procedure for which the surgical instrument is used; however, for some typical embodiments, the predetermined distance will have a maximum value of about 1 cm, for other typical embodiments, about 5 mm, and for yet other typical embodiments, about 1 mm. The jet-receivingopening193 typically will have a diameter of between about 0.01 and about 0.2 inches, in other embodiments between about 0.03 and about 0.1 inches, and in some preferred embodiments a diameter of about 0.06 inches.
• Referring again toFIG. 6A, a preferred configuration forevacuation lumen120 will now be described. Preferred embodiments ofevacuation lumen120 for use in surgical instruments intended to be operated in a liquid environment include amaceration region306 within and/or downstream and in close proximity to the inlet toevacuation lumen120 at jet-receivingopening193.Maceration region306 is defined as a region that contains a liquid undergoing intensely turbulent flow and impacting an internal surface of the evacuation lumen at an acute angle, thus creating significant impacting forces capable of macerating entrained material/tissue, when the instrument is in operation. The combination of the intensely turbulent flow of the liquid inmaceration region306 and the impacting forces ofliquid cutting jet296 and the liquid inentrainment region302 against the wall ofevacuation lumen120 enable the liquid within the maceration region to macerate at least a portion of any tissue or material entrained by the liquid inentrainment region302 into a plurality of small particles. In preferred embodiments, the maceration region is able to macerate a substantial fraction (i.e., the majority of) the entrained tissue into a plurality of small particles. In most preferred embodiments, the plurality of particles at least partially comprises a plurality of microscopic particles too small to be seen unaided with the human eye. In all cases, the particles should be small enough to pass throughevacuation lumen120 without plugging the evacuation lumen, when the instrument is in operation.
• In order to provide a maceration region,evacuation lumen120 preferably includes a jet-deflectingportion308 that is located adjacent to and downstream of jet-receivingopening193. Jet-deflectingregion308 may be either a straight surface that is angled with respect to the direction of at least a central portion ofliquid cutting jet296, or in preferred embodiments, jet-deflectingregion308 comprises a smoothly curved surface upon which at least a portion ofliquid cutting jet296 impinges, where the curved surface is shaped to deflect at least a portion, and preferably all of theliquid cutting jet296 and liquid comprisingentrainment region302 in a direction that is essentially parallel to thelongitudinal axis312 ofevacuation lumen120 in the region proximal to the jet-deflectingregion308. In preferred embodiments, the radius of curvature of the curved surface defining jet-deflectingregion308 is essentially constant, having a value of between about 0.5 and about 20 times the internal diameter ofevacuation lumen120. In one preferred embodiment, the radius of curvature of the curved surface defining jet-deflectingregion308 is essentially equal to the internal diameter ofevacuation lumen120 at jet-deflectingregion308, so that essentially no portion of jet-receivingopening193 projects radially beyond a perimeter defined by anouter surface314 of a portion of the evacuation lumen located proximal and adjacent to jet-deflectingregion308. It is also generally preferable for the surgical instruments provided by the invention that the liquid cutting jet be directed into the jet-receiving opening so that a direction of at least a central portion of the liquid cutting jet forms an angle of no greater than about 20 degrees, and more preferably no greater than about 10 degrees, with respect to a line normal (i.e., perpendicular) to a plane defining (i.e., co-planar to) the jet-receiving opening. In the most preferred embodiments, the central portion of the liquid jet is essentially parallel to a line that is normal to the plane defining the jet-receiving opening.
• In order to provide effective eductor pump action ofevacuation lumen120, in some embodiments,evacuation lumen120 will have an essentially constant internal cross-sectional area from jet-receivingopening193 to a position that is proximal to the distal end of the surgical instrument where the proximal end of the evacuation lumen is located. In other embodiments, eductor pump action can be enhanced by providing an evacuation lumen having an essentially constant cross-sectional area and having a jet-receiving opening, which has a cross-sectional area that is less than the cross-sectional area of the evacuation lumen (i.e., the internal cross-sectional area of the evacuation lumen has a minimum value at the jet-receiving opening). In yet other embodiments, eductor pump action can be enhanced by providing an evacuation lumen having an internal cross-sectional area which increases continuously from a minimum value at the jet-receiving opening to a maximum value at a predetermined position located proximal to the jet-receiving opening. In such embodiments, this maximum value of the internal cross-sectional area should be essentially constant for positions within the evacuation lumen that are proximal to the above-mentioned predetermined position. In each of the above-mentioned embodiments, there are preferably essentially no reductions in the internal cross-sectional area of the evacuation lumen at any position proximal and/or downstream of the maceration region described above.
• FIG. 6B shows an alternative design embodiment for the construction of the evacuation lumen for surgical instruments designed for use in a liquid surgical environment.Evacuation lumen320 includes aconstriction322 in the internal cross-sectional area of the evacuation lumen. Theconstriction322 is located proximal to jet-receivingopening324, and is preferably positioned immediately proximal and adjacent to macerationregion326. In operation, theconstriction322 in theevacuation lumen320 will act as a venturi as liquid within the evacuation lumen flows through the constriction, thus enhancing the eductor pump action ofevacuation lumen320. In the illustrated embodiment,constriction322 comprises apinch328 in the sidewall of the tubing conduit comprisingevacuation lumen320. In preferred embodiments, the cross-sectional area ofconstriction322 should be between about three and about eight times the cross-sectional area of jet-opening294 innozzle192.
• Referring again toFIG. 6A,evacuation lumen120 is shaped and positioned relative topressure lumen118 so that at least a central portion ofliquid cutting jet296 is directed into jet-receivingopening193 in a direction forming a non-zero angle with respect to (i.e. non-parallel with) thelongitudinal axis312 ofevacuation lumen120 in a region proximal to jet-deflectingregion308. In some embodiments, this angle can be between about 45 degrees and about 115 degrees, in other embodiments between about 80 degrees and about 100 degrees, and in some preferred embodiments, as illustrated, the angle can be about 90 degrees.
• As described above, in some embodiments of the invention involving surgical instruments including rotatable shafts, liquid and debris surrounding a grinding burr, or other tissue contacting component at a distal end of the rotatable shaft, can be evacuated by coupling a sheath of the instrument surrounding the rotatable shaft to a source of external vacuum or suction. In other embodiments, also as mentioned above, rotation of the rotatable shaft itself may be utilized to generate an evacuating force for removing liquid and debris from an area surrounding the distal end of the rotatable shaft.FIG. 7A shows a partial section of a distal region ofrotatable shaft400 that is constructed and arranged to generate an evacuation force tending to drive liquid and debris from the distal end of asheath surrounding shaft400, when it is assembled within a surgical instrument according to the invention, to the proximal end of such sheath. “Constructed and arranged to generate an evacuation force” as used herein in the present context refers to the ability of a rotatable shaft, rotating either within a surrounding sheath or without a surrounding sheath, to be able to drive liquid from a region near the distal end of the rotatable shaft towards the proximal end of the rotatable shaft and out of a surgical field into which a distal end of the rotatable shaft is placed, without the need for an external source of suction.
• In operation,rotatable shaft400 rotates in a direction shown byarrow402.Rotatable shaft400 includes aportion404 of increased cross sectional dimension, preferably having a cross sectional dimension only slightly less than an internal cross sectional dimension of a surrounding sheath in whichrotatable shaft400 is disposed when assembled into a surgical instrument.Region404 includes a helically groovedchannel406 machined therein. Bothregion404 andchannel406 are positioned onshaft400 so that they are surrounded by a sheath when assembled into a surgical instrument. Rotation ofshaft400 in the direction ofarrow402 during operation creates a driving force tending to move fluid and debris from the distal end ofshaft400, in proximity to grindingburr408, to a proximal end of the shaft and out of the surgical field in whichburr408 is operating.
• FIG. 7B shows a partial view of a distal region of an alternative embodiment of arotatable shaft410 that is constructed and arranged to generate an evacuation force upon rotation in the direction ofarrow412.Shaft410 includes grindingburr414 at a distal end thereof, and further includesimpellers416, which are disposed within a surrounding sheath whenshaft410 is assembled into a surgical instrument, according to the invention. Upon rotation within the surrounding sheath,impellers416 generate an evacuation force tending to drive liquid and debris towards the proximal end of the shaft during operation of the instrument.
• FIG. 7C shows yet another embodiment of a rotatable shaft constructed and arranged to generate an evacuation force upon rotation.Rotatable shaft416, having grinding burr418 at a distal end thereof, has an interior that is hollow forming achannel420, which extends distally up to atleast aperture422 in scoop424 (scoop424 together withaperture422 will be hereinafter collectively referred to as a “scoop-shaped aperture”425).Aperture422 is in fluid communication withchannel420 formed along the hollow shaft ofrotatable shaft416. Upon rotation ofshaft416 in the direction ofarrow426 scoop-shapedaperture425 scoops fluid and debris intoaperture422 and creates a driving force tending to move the fluid and debris in the direction ofarrow428 towards the proximal end ofshaft416. In preferred embodiments, the scoop-shapedaperture425 is disposed within a surrounding sheath whenshaft416 is assembled into a surgical instrument, according to the invention, and the scoop-shapedaperture425 is shaped and positioned to be able drive liquid and debris throughchannel420 toward the proximal end of the surgical instrument upon rotation ofshaft416 during operation of the instrument. “Shaped and positioned to drive liquid and debris” when used in the context of the scoop-shapedaperture425 refers to a projectingscoop424 having anaperture422 therein that is in fluid communication with acentral channel420 of ashaft416 that rotates in a givendirection426, where theaperture422 within thescoop424 faces in a direction with respect to the rotation of the shaft such that upon rotation of the shaft, liquid and debris tends to be forced through the aperture and into and along the channel defined by the hollow shaft. As will be discussed in greater detail in the context ofFIGS. 11A-11B, for embodiments including rotatable shafts that generate their own evacuation force, in addition to evacuating a region of a surgical field surrounding the distal end of the rotatable shaft, the evacuation force created by the rotating shaft may also be used to create an evacuation force tending to evacuate other regions of the surgical instrument, for example regions of the housing containing the drive mechanism for the rotatable shaft.
• FIG. 8A shows an exploded perspective view of one preferred embodiment for rotatableshaft drive mechanism152. Rotatableshaft drive mechanism152 includes a liquid jet-drivenrotatable rotor450, which in the embodiment illustrated inFIG. 8A comprises a saw-tooth rotor. Upon assembly of the three subcomponents of rotor housing154 (i.e.,rotor cap158,rotor housing block160 and rotor housing bottom162),rotatable rotor450 is contained and rotates within arotor slot452 included inrotor housing block160 androtor housing cap158.Rotatable rotor assembly454 includes, in addition torotatable rotor450,rotor bearings172 and456 disposed at each end of acentral shaft458, upon which the assembly rotates.Bearings172 and456 are held withinflanges460 and462 upon assembly of the rotor housing.
• Rotor assembly454, in the illustrated embodiment, also includes aworm gear464 which mates with acomplementary worm wheel466 located on rotatable shaft drive assembly468 (shown more clearly in an assembled state inFIG. 8B). Gear reduction mechanisms utilizing worm gears, such as illustrated inFIG. 8A, are preferred for some embodiments because they provide relatively high gear reduction ratios for their size. In other embodiments, where a lower degree of gear reduction and a lower difference in rotational speed betweenrotatable rotor450 and driveshaft470 of rotatableshaft drive assembly468 is required or desired, other means of gear reduction, for example spur gears, helical gears, or any other suitable gear reduction mechanisms apparent to those of ordinary skill in the art can be utilized. In addition, for embodiments where high speeds are required or desired or only low torques are necessary during operation, the gear reduction mechanism may be eliminated entirely and therotatable rotor assembly454 may be utilized to driverotatable shaft124 directly. In such an embodiment, rotatableshaft drive mechanism152 could dispense entirely with rotatableshaft drive assembly468, and instead couple therotatable shaft124 directly torotatable rotor assembly454. Of course, in such embodiments, it is desirable to positionrotatable rotor assembly454 so that itslongitudinal axis472 is aligned parallel to longitudinal axis of rotatable shaft124 (i.e., it would be desirable to orientrotatable rotor assembly452 in the orientation currently shown for rotatableshaft drive assembly468 inFIG. 8A).
• Rotatableshaft drive assembly468, as illustrated, is comprised ofdrive shaft470 to which is attachedworm wheel466. The assembly also includes twoshaft drive bearings230 and474 which permit rotation ofdrive shaft470 upon assembly of rotatableshaft drive mechanism152.Bearings230 and474 are held by flanges (e.g.,476) provided in the housing components, upon assembly of the mechanism.Bearings172,456,230, and474, as illustrated, comprise ball bearings; however, in alternative embodiments the bearings may comprise journal bearings, hydrodynamic bearings, or any other suitable bearings as apparent to those of ordinary skill in the art.
• The components comprising rotatableshaft drive mechanism152 are preferably formed from a rigid, durable material, such as a variety of metals, for example surgical grade stainless steel. Becauserotatable rotor assembly454 and rotatableshaft drive assembly468 rotate at high velocity during operation of the instruments, it will be apparent to those of ordinary skill in the art that therotatable rotor450,worm wheel466, and other components comprising the assemblies should be properly balanced so that they can rotate at high rotational speeds without undue vibration of the instrument. Rotatableshaft drive assembly468 further includes attached to its distal end rotatableshaft mounting component480 having adistal surface482 including a rotatableshaft mounting slot484 that is sized and shaped to surround and couple tocoupling region200 ofrotatable shaft124, when the instrument is fully assembled.
• Rotatableshaft drive mechanism152 includespressure lumen164 which supplies high pressure liquid tonozzle490 having jet opening492 therein for forming a liquid jet that is directed to impinge uponrotatable rotor450, thus driving rotation of the rotor and the rotatable shaft, when rotatableshaft drive mechanism152 is assembled and operated. Upon assembly, as previously illustrated inFIG. 4,pressure lumen164 is held in position torotor housing block160 by means of rotor jet pressurelumen mounting blocks264,266. Upon assembly and attachment ofpressure lumen164 torotor housing block160,nozzle490 passes intorotor housing block160 throughorifice494 so thatjet opening492 is oriented to properly direct a liquid jet at rotatable rotor450 (shown more clearly inFIGS. 8C and 8D and discussed below). In addition, and not shown in the current figure, rotorjet evacuation lumen166, rotor housingcap evacuation conduit168, and rotor housingbottom evacuation conduit170 are connected to the various components of rotatableshaft drive mechanism152, as shown and discussed previously, to enable essentially complete evacuation of liquid from the internal spaces surrounding the rotatable components of the mechanism, upon assembly of the mechanism, to prevent submersion of rotatable rotor or the rotatable components in liquid, when the instrument is in operation.
• FIG. 8B is a perspective view ofrotatable rotor assembly454 and rotatableshaft drive assembly468 as they are coupled upon assembly of rotatableshaft drive mechanism152. As shown inFIG. 8B, the various housing components have been eliminated to showassemblies454 and468 with greater clarity. As is shown in the figure, for embodiments having a drive mechanism including gear reduction (e.g., provided byworm gear464 andworm wheel466 as illustrated) it is preferred to alignrotatable rotor assembly452 such that itslongitudinal axis472 is essentially perpendicular tolongitudinal axis496 of rotatableshaft drive assembly468.
• As will be apparent to those of ordinary skill in the art, the particular rotational speeds ofrotor450,rotor drive assembly454, and driveshaft470 of rotatablerotor drive assembly468 must be selected based upon the needs of the particular surgical application and on the characteristics of the particular rotatable component being utilized for tissue contact and being rotated by the rotatable shaft. For typical applications utilizing the inventive surgical instruments, the rotational speed ofrotatable rotor450 will be at least about 16,000 RPM, in other embodiments at least about 65,000 RPM, in yet other embodiments at least about 130,000 RPM, in yet other embodiments at least about 250,000 RPM, and in still other embodiments at least about 500,000 RPM. The diameter ofrotatable rotor450 is typically at least about 0.5 inch, in other embodiments at least about 1 inch, in other embodiments at least about 2 inches, in other embodiments at least about 5 inches, and in yet other embodiments at least about 10 inches. The gear reduction mechanism is selected and configured in preferred embodiments, so that the rotational speed ofrotatable rotor450 will exceed the rotational speed ofdrive shaft470 of rotatablerotor drive assembly468. In typical embodiments, the rotational speed ofrotatable rotor450 will exceed that ofdrive shaft470 by at least about a factor of 2, in other embodiments by at least about a factor of 5, in other embodiments by at least about a factor of 10, in other embodiments by at least about a factor of 20, and in yet other embodiments by at least about a factor of 30. In one particularly preferred embodiment involving a surgical instrument including a rotatable shaft having a 5 mm diameter fluted burr at a distal end thereof, which is utilized for bone grinding in a surgical operating field,rotatable rotor450 comprises a 1 inch diameter saw-tooth rotor having between about 10 and 200 teeth, and in one preferred embodiment about 80 teeth, which is driven at a rotational speed during operation of about 130,000 RPM and is coupled to driveshaft470 via a worm-gear reduction mechanism such that the rotational speed ofdrive shaft470 is about 1/10th that ofrotatable rotor450 during operation.
• For embodiments utilizing a rotatable rotor which is a saw-tooth rotor, depending on the diameter of the saw-tooth rotor and the size of the teeth when compared to the diameter of the rotor, the number of teeth provided on the rotor can range from about 10 to about 200. As discussed immediately above, one particularly preferred saw-tooth rotor embodiment comprises a 1 inch diameter rotor having a thickness of about 0.040 inch and having about 80 teeth therein, each tooth providing a jet impacting surface about 0.040 inch wide by 0.040 inch in height.
• FIGS. 8C-8E are detailed views ofrotatable rotor450 androtatable rotor assembly454 showing the configuration of the rotatable rotor with relation to liquidjet forming nozzle490 and rotorjet evacuation lumen166, when rotatableshaft drive mechanism152 is assembled. For clarity, components other than the rotatable rotor assembly, pressure lumen and evacuation lumen are not shown in the figures. Referring toFIG. 8C,rotatable rotor450 comprises a saw-tooth rotor including a plurality ofteeth498 each including an essentially planar impactingsurface500 upon whichliquid jet502 impacts, when the instrument is in operation.Nozzle490 ofpressure lumen164 is preferably configured to create an essentially collimated liquid jet as a high pressure liquid streams therethrough. The particular configuration ofnozzle490 can be essentially equivalent to that discussed previously with respect to preferred nozzles for forming liquid cutting jets at the distal end of the surgical instrument. Specifically,nozzle490, in preferred embodiments, has a length to minimum internal diameter ratio of between about 2 and about 10 with a preferred length to minimum internal diameter ratio of about 6.Jet opening492 is positioned at a selected predetermined distance from the impactingsurface500 upon whichliquid jet502 impacts, when the instrument is in operation. This predetermined distance, in preferred embodiments, is the minimum distance possible, without havingteeth498 of therotor impacting nozzle490 upon rotation of the rotor. For example, when utilizing a 1 inch diameter saw-toothrotor having teeth498 with a height of about 0.040 inch, the distance between jet opening492 and the impacting surface of the saw tooth upon which the liquid jet impacts, is preferably less than about 1 cm, and more preferably less than about 1 mm.
• In preferred embodiments, predetermined distance, nozzle length to minimum internal diameter ratio, and the size of each impactingsurface500 are chosen so that essentially the entirety ofliquid jet502 impacts an impactingsurface500 of the rotor during operation. In other words, the above parameters are preferably selected so that at the point ofimpact506 ofliquid jet502 with an impactingsurface500, the cross-section ofliquid jet502, within the plane of impactingsurface500, is essentially entirely incident on impactingsurface500 so that essentially no part of the liquid jet “misses” or “blows by” the impacting surface. In such a situation, the momentum of the entire liquid jet can potentially be imparted torotatable rotor450 to create rotational motion of the rotor.
• The distal end of rotorjet evacuation lumen166 is shown partially cutaway inFIG. 8C to more clearly shownozzle490,liquid jet502, androtatable rotor450, as positioned within the distal end of the lumen. As shown more clearly inFIGS. 8D and 8E, the distal end ofevacuation lumen166, which is disposed withinrotor housing block160 upon assembly of rotatableshaft drive mechanism152, includes aslit504 in which a portion ofrotatable rotor450 is located during operation. Furthermore, the distal end ofpressure lumen164 includingnozzle490 is also positioned within and essentially completely surrounded by the distal end ofevacuation lumen166 when the drive mechanism is assembled. This configuration serves to maximize the containment of any spray that is created upon the impacting ofliquid jet502 with an impactingsurface500 ofrotatable rotor450. This is especially important for periods of operation of the instrument where the rotatable shaft of the instrument is subjected to significant torque tending to inhibit its rotation. During such periods of operation,rotatable rotor450 will tend to rotate at a speed that is less than the velocity ofliquid jet502. Under such conditions,liquid jet502 can have a tendency to form spray or mist upon impacting an impactingsurface500. By contrast, under conditions of free rotation,rotatable rotor500 rotates at a speed essentially equal to the speed ofliquid jet502, so that the trajectory ofliquid jet502 remains essentially constant even after impacting an impactingsurface500, and minimal spray is created. In an alternative embodiment, the evacuation lumen can be configured and positioned so that it does not surround and enclose any portion of the distal end of pressure lumen but, instead, is positioned distally of the nozzle in the pressure lumen, preferably with a jet-receiving opening positioned within about 0.01 inch of the jet opening in the nozzle.
• The design ofevacuation lumen166 as illustrated enables effective evacuation of essentially all of the liquid comprisingliquid jet502 from the housing enclosing the rotatable rotor assembly during operation of the device under a wide range of loads and resistances applied to the rotatable shaft of the instrument. In certain embodiments, the proximal end ofevacuation lumen166 can be placed in fluid communication with a source of external suction in order to effect evacuation of liquid comprisingliquid jet502. In some preferred embodiments,liquid jet502, via eductor pump action, described previously, is able to create its own evacuation force tending to evacuate the liquid comprisingliquid jet502, together with any spray formed upon impacting with a surface of the rotor, from the distal end ofevacuation lumen166 without the need for an external source of suction.
• In typical embodiments, jet opening492 innozzle490 has a diameter of between about 0.001 and about 0.02 inch, more preferably between about 0.003 and 0.01 inch, and in one preferred embodiment has a diameter of about 0.005 inches. In typical embodiments, liquid is supplied tonozzle490 to form a liquid jet at a pressure of at least about 1,000 psig, in other embodiments at least about 5,000 psig, in another embodiments at least about 15,000 psig, and yet in other embodiments, at least about 30,000 psig. In one preferred embodiment, liquid is supplied tonozzle490 to form a liquid jet at a pressure of about 8,000 psig.Evacuation lumen166, in typical embodiments, has ajet receiving opening508 having a diameter of between about 0.01 and about 0.3 inches, more preferably between about 0.05 and about 0.2 inches and in one preferred embodiment about 0.12 inches. As will be discussed below in more detail in the context ofFIGS. 11A-11B, for embodiments whereinliquid jet502 is directed into anevacuation lumen166 creating an evacuation force by eductor pump action without the need for an external source of suction, this evacuation force can be utilized not only to evacuate liquid comprisingliquid jet502, but also to evacuate or assist in evacuating other components of the surgical liquid jet instrument.
• Rotatable rotor450 is shown schematically and in greater detail inFIGS. 9A and 9B.FIG. 9A showsrotatable rotor450 as viewed from the same orientation as shown inFIG. 8C above.FIG. 9A illustrates a preferred embodiment for orientating and directingliquid jet502 at an impactingsurface500 ofsaw teeth498 onrotatable rotor450.FIG. 9B showsrotatable rotor450 as viewed from above, more clearly showing the orientation of the fluid jet within the plane of the rotor. The direction of the liquid jet is shown byarrows510 and512 in the figures. As shown in the figures, it is preferred to direct the liquid jet towardssurface500 ofrotatable rotor450 so that it impacts the surface at a non zero angle (i.e., the liquid jet is not directed tangentially to the surface). Even more preferably, as shown inFIG. 9B, the liquid jet is directed towards impactingsurface500 ofrotatable rotor450 such that the direction of theliquid jet510,512 is essentially perpendicular to the surface, at least as measured in the x-z plane as illustrated inFIG. 9B. As shown inFIG. 9A, in some embodiments, for example those having a liquid jet directed alongdirection510, the liquid jet can be directed atsurface500 so that it is also essentially perpendicular to the surface as measured in the y-z plane, illustrated inFIG. 9A. In other embodiments, the liquid jet can be directed alongliquid jet direction510, such that the liquid jet is directed towardsurface500 at a relatively small angle as measured within the y-z plane so that the liquid jet is angled somewhat to impinge closer to thebase514 ofsaw tooth498. The term “essentially perpendicular,” when used in the context of describing the direction of a liquid jet with respect to an impacting surface of a rotatable rotor, refers to the liquid jet being directed towards the impacting surface of the rotatable rotor such that it is essentially perpendicular to the surface in at least the x-z plane as illustrated inFIG. 9B.
• Preferred saw tooth rotors have liquid jet impacting surfaces that are essentially planar. Furthermore, as described above in the preceding paragraph, the surfaces are preferably oriented with respect to the rotor such that each impacting surface is oriented essentially perpendicularly (or is essentially perpendicular to) a liquid jet impacting thereon at at least one rotational position of the rotatable rotor. Furthermore, in preferred embodiments, each liquidjet impacting surface500 ofrotatable rotor450 is also oriented at an angle of between about 75 degrees and about 105 degrees with respect to aline516 tangent to the circle circumscribed by the outermost perimeter of the rotor as it rotates about its axis ofrotation518. In some especially preferred embodiments, each liquidjet impacting surface500 ofrotatable rotor450 is oriented essentially perpendicularly toline516 In alternative embodiments, a rotor having liquid jet impacting surfaces that are curved may be utilized in place of a saw tooth rotor having planar impacting surfaces, as previously described.FIG. 10A shows a perspective view of a curved-vane rotor520 having curved liquid jet impacting surfaces522. Curved impacting surfaces522 are defined by a series ofcurved vanes524 positioned along the periphery ofrotor520. As illustrated, preferred curved-vane rotors have impactingsurfaces522 that are oriented to provide an impacting surface that is concave with respect to the direction of an incoming liquid jet, shown byarrow526. In the illustrated embodiment, curved impactingsurfaces522 comprise semi-cylindrical surfaces. For embodiments utilizing rotors having smoothly curved liquidjet impacting surfaces522, it is preferred for the liquid jet to be oriented in adirection526 such that it is directed towardsurface522 essentially tangentially to the surface.
• FIG. 10B illustrates a particularly preferred configuration for orienting and positioningcurved vanes524 around the periphery ofrotor520. As illustrated inFIG. 10B, in a preferred embodiment, angle a formed between the line523 tangent to impactingsurface522 of the curved vane and theline525 defining the edge ofrotor520 should be between about 5 degrees and about 30 degrees, and in a preferred embodiment is about 17 degrees. In addition, channel width h betweencurved vanes524, through which the liquid comprising an impacting liquid jet flows when the rotor is in operation, is preferably between about the diameter of the impacting liquid jet at the point of impact and a value of about twice the diameter of the liquid jet. In addition, the width of curved vanes524 (C) is preferably chosen with respect to the inter-vanes spacing (S) such that the ratio (C/S) is between about 1.0 and about 1.5. In yet other embodiments, a smoothly curved jet impacting surface may be provided by utilizing a Terry rotor for driving the rotatable shaft of the surgical instrument. Terry rotors are known in the mechanical arts and are described in greater detail in, for example, Balje, O. E.Turbomachines: A Guide to Design, Selection, and Theory,John Wiley & Sons, New York, N.Y., 1981, pp. 252-256.
• FIGS. 11A and 11B show two potential configurations for supplying evacuation to the various evacuation lumen and conduits ofsurgical instrument100. In another embodiment, not illustrated, an external source of suction is coupled in fluid communication to each of the evacuation lumen and evacuation conduits ofsurgical instrument100 in order to provide a suction force to each that is generated by the external source of suction. In alternative embodiments, suction created by the eductor pump action of cuttingjet evacuation lumen120, rotorjet evacuation lumen164, and/or the suction force created by any of the self-evacuating rotatable shaft designs shown previously inFIGS. 7A-7C can instead be utilized to supply a source of suction for evacuating various other evacuation conduits ofinstrument100.
• FIG. 11A illustrates one embodiment for evacuating the various evacuation lumen and conduits ofinstrument100. For the illustrated embodiment, the rotatable shaft of the surgical instrument would not be configured to provide self-evacuation. Accordingly, an external source ofsuction530 is coupled in fluid communication toevacuation conduit532, which in turn, is in fluid communication with thesheath132 surrounding the rotatable shaft. By contrast, the remaining evacuation lines of the instrument are each connected to a manifold534 configured as shown. Fluid momentum supplied by the eductor pump action of the rotorjet evacuation lumen166 in combination with liquid cuttingjet evacuation lumen120 is utilized to create a suction force withinmanifold534 sufficient to evacuate theevacuation conduit168 connected torotor housing base162 and theevacuation conduit170 connected torotor housing cap158. It should be understood thatmanifold534 may be formed by connecting the exhaust lumen/conduits in the manner shown inFIG. 11A outside of the body of the surgical instrument (as would be the case if usingsurgical instrument100 as illustrated inFIG. 1 above); however, in other embodiments, manifold534 can be configured to and contained within the body of the surgical instrument.
• FIG. 11B shows an alternative embodiment for a surgical fluid jet instrument that includes a rotatable shaft configured to create an evacuation force upon rotation of the shaft, as previously described inFIGS. 7A-7C. With such a configuration, the external source of suction can be eliminated entirely, and the entire surgical instrument can be configured to be self-evacuating without the need for an external source of suction. In the illustrated embodiment, the various evacuation lumen and conduits are connected to amanifold542. In the illustrated embodiment, the liquid momentum supplied by the eductor pump action of rotorjet evacuation lumen166 and liquid cuttingjet evacuation lumen120 are utilized in combination with the liquid motive force supplied by the rotatable shaft throughsheath132 to create a sufficient suction inmanifold542 to evacuateevacuation conduit168 connected torotor housing block160 andevacuation conduit170 connected to therotor housing base162 of the surgical instrument.
• A cross-sectional view showing the internal details of liquidflow directing valve180 is illustrated inFIG. 12. Liquidflow directing valve180 includes avalve body550 formed of a rigid sturdy material, for example surgical grade stainless steel, having a centrally disposed bore therein forming acylinder552 internal tovalve body550.Valve180 is configured as a slidable three-way valve.Valve body550 further includes aninlet182 comprising a bore having threaded walls configured to mate with a high pressure tubing coupling186 (shown inFIG. 1). Similarly,valve body550 further includes a first188 and a second194 outlet configured with internally threaded surfaces for coupling tohigh pressure connectors190 and196 respectively.
• Disposed within centrally disposedcylinder552 is ashaft554, preferably comprised of a rigid, durable metal such as surgical grade stainless steel, connected bythreads555 at each end to user actuatedknobs197. Also disposed onshaft554 are twoelements556 comprising pressure tight sealing components for preventing leakage of high pressure liquid from and withinvalve180.Elements556 comprising the pressure tight sealing components are described in greater detail below in the context ofFIGS. 13A and 13B.Elements556, while shown for use within the context of liquidflow directing valve180, can also be used for a wide variety of other applications where a high pressure, slidable sealing component is needed to form a high pressure seal between a shaft or piston and the walls of a cylinder. Pressuretight sealing components556 are separated alongshaft554 by acylindrical spacer sleeve558 surroundingshaft554 and disposed between the pressure tight sealing components. Pressuretight sealing components556 are forced againstspacer558 to prevent relative motion betweenshaft554 and the pressure tight sealing components by tighteningknobs197 onto the threaded ends ofshaft554 to provide a biasing force pushing the pressuretight sealing components556 againstspacer558.
• Spacer558 has an external diameter less than that of the internal diameter ofinner surface560 ofcylinder552. Thus, a space provided between theouter surface562 ofspacer558 and theinner surface560 ofcylinder552 defines aflow channel564 through which high pressure liquid flows frominlet182 to either or both ofoutlets188 and194, when the instrument is in operation. In some preferred embodiments,valve180 can be adjusted by the user, by manipulating the position ofshaft554 withknobs197, to provide three user-selectable positions. In especially preferred embodiments, the three user-selectable positions can be defined by discreet stops along the direction of movement ofshaft554 withincylinder552. For example, in one particular embodiment, the shaft and cylinder sliding mechanism can be configured, upon a force applied to one or both ofknobs197 to move between three discreet positions along the length of travel of the shaft within the cylinder, each position defining a particular flow path and requiring a force applied toknobs197 to dislodge the shaft from the discreet position. A variety of mechanisms for providing such discreet sliding action between predefined positions are well known to those of ordinary skill in the art. In other embodiments, where liquid flow exiting both outlets simultaneously is not desired,shaft554 ofvalve180 may be configured, for example with a bistable mechanism, to permitvalve180 to be adjusted by the user to one of two discreet positions, one for directing flow tooutlet188 and the other for directing flow tooutlet194.
• As illustrated inFIG. 12,shaft554 has been moved to the far right of its permissible range of motion. This position defines a first user-selectable position directing a high pressure liquid frominlet182 throughflow channel564 and out of the valve throughoutlet188, which is fluid communication withpressure lumen118 supplying high pressure liquid to liquid cuttingjet nozzle192 shown inFIG. 1. Such position would be selected by the user of the surgical jet instrument in order to create a liquid cutting jet with the surgical instrument without creating rotation of the liquid jet-driven rotatable shaft of the surgical instrument. A second user-selectable position would be the position obtained by slidingshaft554 to its leftmost range of travel. In this configuration, high pressure liquid would flow frominlet182 throughflow channel564 and out of the valve throughoutlet194, which is in fluid communication with rotordrive pressure lumen164. This configuration can be utilized for driving a liquid jet-driven rotatable shaft of the instrument without simultaneously creating a liquid cutting jet with the instrument. Yet a third user-selectable position, in some embodiments, can be achieved by positioningshaft554 at a position roughly equidistant between its rightmost and leftmost ranges of travel. In this third user-selectable position, high pressure liquid will flow frominlet182 throughflow channel564 and out of the valve through bothoutlets188 and194. In this configuration, the user may create a liquid cutting jet with the instrument while simultaneously powering a liquid jet-driven rotational shaft of the instrument.
• Elements556 are shown in greater detail inFIG. 13.Element556 is configured as a pressure-tight sealing component. A “pressure-tight sealing component” as used herein refers to a component that is able to form a pressure-tight seal between two regions of a cylinder, each containing a fluid therein, wherein the fluids contained in the two regions are at different hydrostatic fluid pressures. A “fluid” when in the present context can comprise a liquid, gas, supercritical fluid, slurry, suspension, or any mixture of the above, and refers to the thermodynamic state of the material present in the regions of the cylinder at the temperature and pressure at which the component is used in operation. In the context of use of the pressure-tight sealing component within liquidflow control valve180, the fluid contained in at least one of the above-mentioned regions of the cylinder will comprise a liquid; however, as apparent to those of ordinary skill in the art,element556 can also be used for a wide variety of other pressure sealing applications not necessarily involving pressurized liquids.
• Element556 is shown in cross section ofFIG. 13 together with a portion ofspacer558.Shaft554 has been removed in the figure to show the illustrated components with greater clarity.Element556 may be comprised of a wide variety of materials capable of withstanding the pressures contemplated, such as, for example, a variety of metals, ceramics, plastics, etc.Element556 is, in preferred embodiments, comprised of a non-elastomeric, semi-rigid plastic that is dimensionally stable within the range of operating pressures contemplated. Preferred plastics include crystalline polymers or semi-crystalline polymers, or amorphous polymers having a glass transition temperature higher than the operating temperature of theapparatus utilizing element556 as a sealing component.Element556 can be constructed from a wide variety of engineering plastics, for example, polytetrafluorethylene (PTFE), polypropylene, polyethylene, polyvinylchloride, polyamides, polysulfone, polystyrene, mixtures thereof, etc., as apparent to those of ordinary skill in the art. In one particular preferred embodiment,element556 is formed from an acetal polymer, for example, polyoxymethylene (Delrin™).
• Element556 includes an integral, flared sealingflange portion559 that is constructed and arranged to make sealing contact with theinternal surface560 ofcylinder552 withinvalve180, while preventing contact betweeninternal surface560 and bothshaft554 and betweeninternal surface560 and any other portion ofelement556 outside offlange region559. “Constructed and arranged to make sealing contact” as used herein in reference to flared sealingflange portion559 refers to at least anouter surface561 of the flange portion being sized and shaped to form an essentially continuous contact withinner surface560 of cylinder552 (i.e., having an outer perimeter with a shape essentially conforming to the shape of cylinder552). It should be emphasized, that while, in the illustrated embodiment, the shape ofcylinder552 and the outer perimeter ofouter surface561 is essentially circular in cross-section (i.e.cylinder552 as illustrated comprises a circular cylinder), in other embodiments, the shape of the cylinder and the outer perimeter of outer surface may be other than circular in cross-section, for example, the cylinder may comprise a cylindrical channel with a rectangular, elliptical, triangular, polygonal, or other cross-sectional shape, with the integral, flared sealing flange portion of the sealing element being similarly shaped so that that is constructed and arranged to make sealing contact with the internal surface of the cylinder. Flared sealingflange portion559 ofelement556, when in sealing contact withinner surface560 ofcylinder552, provides a leak-tight seal at the point of contact between the flared sealing flange portion of the element and the internal surface of the cylinder that is able to withstand a differential in liquid pressure of at least about 1,000 psi without leakage of liquid through the seal. A “differential in liquid pressure” as used herein in the present context refers to a difference in hydrostatic pressure between a liquid contained withinflow channel564 ofcylinder552 and a pressure outside of the region of flow channel564 (e.g., atmospheric pressure) withincylinder552. In more preferred embodiments, the seal formed betweenflange region559 andsurface560 ofcylinder552 is capable of withstanding a differential in liquid pressure of at least 8,000 psi, more preferably at least 25,000 psi, and most preferably at least 50,000 psi without leakage of liquid through the seal.
• In the illustrated embodiment,element556 is shaped to include amain body portion563 having a cylindrical shape with an outer diameter D_I. As illustrated,flange portion559 ofelement556 is formed integral to surface565 abuttingspacer558.Surface565 also includes aridge566 for seating against angledinternal surface568 ofspacer558. In other embodiments, flared sealingflange portion559 may be located alongmain body portion563 at a position intermediatespacer abutting surface565 andknob abutting surface570. It should also be understood that inother applications element556 may be configured as acap having surface565 extending completely across the centrally disposed bore572 within the interior of the element. Such a configuration could potentially be useful for use as a pressure sealing cap on the end of a shaft.
• As configured for use inliquid directing valve180,element556 has amain body portion563 configured with a tube-like annular shape, wherein centrally disposed bore572 is disposed entirely through the central region of the element, permitting the element to be mounted toshaft554, which shaft passes through centrally disposed bore572, when the element is mounted to the shaft.
• Flared sealingflange portion559 ofelement556 has apredefined length574 and is angled to extend away fromouter surface576 ofmain body portion563 and towardinner surface560 ofcylinder552 ofvalve180 when the valve is assembled. The flared sealingflange portion559 extends away fromsurface576 ofmain body portion563, as shown, to form a cantilevered circumferential flange around the periphery ofelement556. A “cantilevered circumferential flange” refers to a flange that circumscribes the entire outer perimeter of the main body portion of the element and is attached to the main body portion along one of its sides, while having at least two additional sides or faces (e.g., surfaces561,577, and578) not attached to or integral with the main body portion of the element (i.e., having a triangular cross-sectional shape or a trapezoidal or rectangular cross-sectional shape).
• Predefined length574 andminimum thickness580 of sealingflange portion559 tend to vary approximately linearly with the size ofcylinder552 in which sealingelement556 is disposed during operation. In one exemplary embodiment utilizing a Delrin plastic element having a main body portion with an external diameter D_Iof about 0.182 inch that is used as a pressure-tight sealing component within a cylinder having an internal diameter of about 0.1875 inch,length574 is about 0.025 inch andthickness580 is about 0.003 inch.
• Sealing element556 has a second outer diameter D_Odefined by anoutermost periphery582 offlange portion559 that exceeds the outer diameter D_Iofmain body portion562. Whenelement556 is disassembled fromcylinder552 ofvalve180, outer diameter D_Oof theoutermost periphery582 offlange portion559 exceeds outer diameter D_Iofmain body portion563 by at least about 1%, in other embodiments by at least about 3%, in other embodiments by at least about 5%, and in yet other embodiments by at least about 10%. In one preferred embodiment, outer diameter D_Oexceeds diameter D_Iby about 5%.Cylinder552 ofvalve180, containingelement556 upon assembly of the valve, has an internal diameter that exceeds outer diameter D_Iofmain body portion563 but that is somewhat less than outer diameter D_Oofoutermost periphery582 offlange portion559 ofelement556. It should be emphasized that outer diameter D_Oofoutermost periphery582 offlange portion559 as described herein refers to the diameter as measured withelement556 disassembled fromvalve180 and not contained withincylinder552. Whenelement556 is inserted intocylinder552,flange portion559, which is pivotally flexible with respect tomain body portion563, will tend to have a maximum outer diameter ofoutermost periphery582 offlange portion559 that is essentially equal to the inner diameter ofcylinder552. Referring now to the maximum outer diameter D_Oofoutermost periphery582 offlange portion559, as measured withelement556 not assembled intocylinder552,cylinder552 typically has an internal diameter less than diameter D_Oby at least about 0.5%, and in other embodiments at least about 1%, and in yet other embodiments by at least about 2%. In a preferred embodiment, the internal diameter ofcylinder552 is less than external diameter D_Oby about 1%.
• Flange portion559 ofelement556, in preferred embodiments, has anouter surface561 extending away fromsurface576 ofmain body portion563 at an angle γ, with respect to the direction oflongitudinal axis590 ofmain body portion563, of between about 1 degree and about 11 degrees. Furthermore, in preferred embodiments,flange portion559 has aninner surface578 extending away fromsurface565 ofmain body portion563 at an angle β, with respect to the direction oflongitudinal axis590, of between about 15 degrees and about 30 degrees. In preferred embodiments, the absolute value of the difference between angles γ and β varies from between about 5 degrees and about 20 degrees. In one preferred embodiment, angle γ is about 8 degrees and angle β is about 20 degrees.
• Another aspect of the present invention provides a series of liquid jet surgical instruments including integrated electrocautery for cauterizing blood vessels or other tissue in a surgical field with an electric current. The term “integrated electrocautery” as used herein to refer to certain embodiments of surgical instruments provided by the invention, refers to the inventive surgical liquid jet instruments including one or more electrodes, preferably located at the distal end of the instrument for placement in the surgical field during operation, which electrodes comprise an integral or attached component of the surgical instrument, such that electrocautery can be performed with the surgical instrument without the need for insertion into the surgical field of any additional instrumentation, and without the need for removal and replacement of the surgical instrument from the surgical field. Integrated electrocautery capability in certain embodiments of the inventive surgical instruments can be configured with a single positive electrode located near the distal end of the surgical instrument and can be operated in a monopolar mode. For such embodiments, the electrode provided by the instrument acts as the positive electrode and the body of a patient acts as a source of ground potential, for example via contact with a grounding pad in electrical communication with an external power supply. A “positive electrode” or “positive terminal” as used herein refers to an electrode or terminal of a surgical instrument or external power supply having an electrical potential differing from that of ground potential (0 volts). A “source of ground potential” as used herein refers to an electrode, surface, terminal, etc., that is maintained at essentially ground potential during performance of electrocautery with a surgical instrument.
• Preferred surgical instruments, according to the invention, including integrated electrocautery further include at least one lumen therein able to conduct an electrically conductive liquid to the distal end of the instrument for insertion into a surgical field. Such a lumen is able to add conductive liquid to the surgical field in order to maintain an electrocautery electrode at the distal end of the instrument submerged in an electrically conductive liquid so as to enable current flow from a positive electrocautery electrode to a source of ground potential within the environment of the surgical field during electrocautery. Especially preferred instruments including integrated electrocautery include a pressure lumen therein able to conduct a high pressure liquid to the distal end of the instrument and able to form a liquid cutting jet within the surgical field. Some preferred surgical instruments will also include an exhaust lumen with a jet-receiving opening, positioned opposite a jet opening in a nozzle region of the above-mentioned pressure lumen, for evacuation of liquid and debris from the surgical field. Some preferred embodiments of surgical instruments including integrated electrocautery can also include a rotatable shaft therein for powering a tissue contacting component, for example a grinding burr. Such an instrument was described previously in the context ofFIG. 1 and is shown and described, as configured with integrated electrocautery below in the context ofFIGS. 16A and 16B.
• In general, the inventive configurations for providing integrated electrocautery described below may be utilized in a wide variety of surgical instruments capable of delivering a conductive fluid, such as physiological saline or lactated Ringer's solution, to a surgical field of a patient, as would be apparent to those of ordinary skill in the art. In other embodiments, where the distal end of the surgical instrument is utilized in surgical fields that are naturally submersed in conductive fluids or are perfused by other means with conductive fluids, the instruments provided by the invention including integrated electrocautery can lack lumen for delivering conductive fluid to the surgical field, but may instead comprise, for example, a surgical instrument providing only a rotatable shaft that is powered by a liquid jet-driven rotatable rotor positioned within the body of the instrument and drivingly coupled to the rotatable shaft, such that rotation of the liquid jet-driven rotatable rotor causes a corresponding rotation of the rotatable shaft of the instrument as well as rotation of a component at the distal end of the rotatable shaft, such as a grinding burr, etc., which is able to perform a desired surgical task within the surgical operating field.
• Some preferred embodiments for providing integrated electrocautery provide surgical instruments having at least two electrodes positioned at the distal end of the instrument and within a surgical operating field during operation of the instrument. Such instruments can be operated in a bipolar mode, where each of the electrodes is maintained at a differing electrical potential, such that there exist a difference in electrical potential between different electrodes of the instrument, tending to drive electrical current along a conducting path within a surgical operating field from one electrode to another. In preferred embodiments of instruments configured with at least two electrodes, at least one of the distal electrodes comprises a positive electrode and at least one other of the distal electrodes comprises a ground potential electrode, such that a complete current path between the positive electrode and the ground electrode at the distal end of the instrument is provided within the surgical field during operation of the instrument.
• As discussed above, integrated electrocautery, as provided by the invention, may be configured to be utilized with a wide variety of surgical instruments both described herein and available in the prior art. For example, a particular embodiment of a deployable liquid jet surgical cutting instrument previously disclosed and described in detail in commonly owned U.S. patent application Ser. No. 09/313,679 configured with the inventive system of integrated electrocautery is described below in the current text ofFIGS. 14A-14D. It should be understood that in addition to the embodiment illustrated inFIGS. 14A-14D, any of the other embodiments of surgical liquid jet cutting instruments described in U.S. patent application Ser. No. 09/313,679 could be similarly configured with integrated electrocautery as provided by the current invention. As described below, in some preferred embodiments, the at least one integrated electrocautery electrode provided at the distal ends of surgical instruments according to the invention comprises at least a portion of a distal end of a lumen of the surgical instrument configured to either supply liquid to a surgical field (e.g., a pressure lumen) or withdraw liquid from a surgical field (e.g., an evacuation lumen). In some such preferred embodiments, as discussed in more detail below, electrodes are provided at the distal end of one or more lumen of the surgical instruments by selectively coating the external surface of such lumens with an essentially continuous layer of an electrical insulator, while leaving certain regions the lumen uncoated, which uncoated regions providing an electrode surface. An “essentially continuous layer” of electrical insulation as used herein for describing certain coated regions of conductive lumen or other surfaces of the surgical instrument according to the invention refers to such surfaces being coated with an electrical insulator such that there is essentially no, or an acceptably low level of, electrical conduction between the coated region of the surface and another surface or medium through the electrically insulating layer at any electrical potentials up to the maximum electrical potential rating of the surgical instrument (about 1500 volts for typical electrocautery instruments as described herein). In other embodiments, the electrode(s) may comprise probes or conductive elements that are separate or separable from the fluid conducting lumen of the instruments.
• An illustrative embodiment for a rotatably deployed surgical liquid jet instrument is shown inFIGS. 14A-14F. Referring toFIG. 14A,surgical instrument600 includes abody602 having agrasping region604 configured to be held within the hand of an operator and anactuating element606 that comprises a slidable sleeve or collar, which is used to deploy thedistal end608 ofsurgical instrument600.Slidable sleeve606 is positioned to be easily actuated by a single hand of an operator ofinstrument600.Slidable sleeve606 can enable the operator to holdbody602 in at least two different hand/graspingregion604 orientations, so that the operator can actuateslidable sleeve606 while holdingbody602 in either of the at least two hand/graspingregion604 orientations. For example, an operator can gripbody602 in a hand position where the thumb of the operator is located near the distal end of grippingregion604. In such position, the operator can actuateslidable sleeve606 by moving the slidable sleeve with her thumb. In a second hand/grasping region orientation, the operator can gripbody602, for example, with her thumb positioned toward the proximal end ofbody602, while actuatingslidable sleeve606 via one or more of the other four fingers of her hand.
• Surgical instrument600 also includes acollar610 that is rotatably mounted withinbody602. Rotatably mountedcollar610 is typically a cylindrically-shaped sleeve, which may be attached to, or form part of,sheath612.Distal end608 ofsurgical instrument600 is shown inFIG. 14A in an undeployed configuration. Slidingsleeve606 in the direction ofarrows614 causes a rotational motion of rotatably mountedcollar610 in the direction shown byarrows616, which, in turn, causes a rotation ofevacuation lumen618 about a longitudinal axis ofsheath612, which is essentially parallel to the longitudinal axis ofbody602 and the longitudinal axis of the portion ofevacuation lumen618 withinsheath612. In other embodiments, upon deployment,evacuation lumen618 may rotate about the longitudinal axis ofsheath612, which is essentially collinear to the longitudinal axis to of the portion ofevacuation lumen618 withinsheath612, both of which axes are essentially parallel to the longitudinal axis ofbody602. In yet alternative embodiments, instead ofevacuation lumen618 rotating upon deployment ofinstrument600,evacuation lumen618 may instead be immobile with respect tobody602 andpressure lumen620 may rotate upon actuation ofslidable sleeve606.
• Surgical instrument600 as shown is also configured with integrated bipolar electrocautery capability. In the illustrated embodiment,pressure lumen620 is configured to include apositive electrocautery electrode622 at its distal end, andevacuation lumen618 includes aconductive portion624 of its outer surface, located withinsurgical field626 during operation, which act as a ground electrode.Pressure lumen620 is coated with an essentially continuous layer626 (shaded region) of an electrical insulator along essentially its entire length, except in aregion622 at its distalend surrounding nozzle628, which is uncoated and has a conductive surface providing a positive electrode. In preferred embodiments, as shown,evacuation lumen618 is uncoated along its length, except in a region630 (shaded region) at its distal end, which region, surrounding the jet-receiving opening, is coated with an essentially continuous layer of electrical insulation. In other embodiments, the roles ofpressure lumen620 andevacuation lumen618 may be reversed so thatevacuation lumen618 is coated along its length except at its distal end and acts as the positive electrode, andpressure lumen620 has an outer surface that is conductive along its length, except at its distal end which is coated, and provides a ground electrode. In yet other embodiments, both the positive and ground electrodes may be positioned on the same lumen (i.e. on the pressure lumen or the evacuation lumen). For example, in one such alternative embodiment, the pressure lumen can be configured as described above (i.e. having an essentially continuous layer of an electrical insulator disposed along essentially its entire length, except in a region at its distal end surrounding the nozzle, which is uncoated and has a conductive surface providing a positive electrode) except also including a ground electrode disposed along or wrapped around the outer, insulated surface of the pressure lumen, where the ground electrode has a distal end that is disposed proximal to the conductive region of the outer surface of the lumen that provides the positive electrode. In such an alternative embodiment, the other lumen, which does not provide an electrode (e.g. the evacuation lumen in the above-described configuration), can be, if desired, constructed from an electrically non-conductive material, such as plastic.
• FIG. 14A shows the distal end ofinstrument600 submersed in an electrically conductive fluid in asurgical field626.Pressure lumen620 is coated with insulatinglayer626 except at its distal tip. The uncoated, uninsulateddistal tip622 forms the positive integrated electrocautery electrode.Evacuation lumen618, in the illustrated embodiment, is uninsulated except atdistal tip630. In the illustrated embodiment,distal tip630 ofevacuation lumen618 is insulated in order to increase the minimum length of theconductive path632 that electrocautery current travels along withinsurgical field626 to prevent burning of tissue at the surface of theground electrode624 and to reduce any arcing, shorting, or burning of tissue that may be caused by providing a conductive path length that is too short. This can be especially important when performing electrocautery withsurgical instrument600 in an undeployed configuration, as shown, where the distal ends ofpressure lumen620 andevacuation lumen618 are in very close proximity.
• Upon operation of electrocautery, current will flow fromelectrode622 and through the target tissue and electrically conductive fluid insurgical field626 to a conducting surface at ground potential, for example theuninsulated surface624 ofevacuation lumen618 andsheath612, which is in electrical communication withlumen618.Positive electrode622 andground electrode surface624 ofevacuation lumen618 within the surgical field are preferably sized, based on the power rating of the power supply supplying power to the positive electrode, to focus electrical energy at the positive electrode and disperse the energy at the ground electrode. In typical prior art electrocautery instruments for performing bipolar electrocautery, the positive and ground electrodes are of essentially equal size. In such prior art instruments, essentially all of the tissue located between the electrodes gets desiccated by electric current during operation of the instrument. In the inventive configuration, it is preferred that the surface area of the ground electrode surfaces that are submerged in conductive liquid withinsurgical field626 exceed the surface area ofpositive electrode622 by at least a factor of 2, more preferably by at least a factor of 5, and most preferably by at least about a factor of 10. In all cases, the ground electrode should be sized, with respect to the size of the positive electrode and the power supplied to the positive electrode, so that it is large enough to prevent boiling of any of the liquid contained withinsurgical field626, when performing electrocautery with the instrument. For example, in the embodiment illustrated,positive electrode622 comprises a positive electrode surface area of about 0.2 cm², while theinsulated surface630 of the distal end ofevacuation lumen618 comprises the distal-most about 0.20 inch of the lumen, providing aconductive surface624 ofevacuation lumen618 insurgical field626 comprising a ground electrode that has a surface area of at least about 2 cm².
• Pressure lumen620 andevacuation lumen618, are connected in electrical communication withpositive terminal632 andground terminal634 ofexternal power supply636 respectively.External power supply636 preferably comprises a radio frequency (RF) generator. For embodiments where the surgical instrument is configured to provide bipolar electrocautery,surgical instrument600 can potentially be used with the bipolar output of essentially any commercially available RF generators for use in electrocautery. Such generator are typically configured to supply frequencies of between about 500 KHz and about 2 MHz at power supply levels up to about 80 watts.Positive terminal632 ofpower supply636 is in electrical communication withbody602 ofinstrument600 viaelectrical connector638 andjack640.Ground terminal634 of power supply is in electrical communication withbody602 ofinstrument600 viaelectrical connector642 andjack644.Jack640 is, in turn, in electrical communication withpressure lumen620 withinbody602 andjack644 is, in turn, in electrical communication withevacuation lumen618 withinbody602 by connections best illustrated inFIG. 14D and described below.Jacks640 and644 andconnections638 and642 can be any of a wide variety of electrical connection means readily apparent to those of ordinary skill in the art. In one particular example, electrical connections betweenbody602 ofinstrument600 are made through standard “banana” jacks that are mounted to the instrument. In some preferred embodiments,jacks640 and644 are eliminated, andconnectors638 and642 are connected directly topressure lumen620 andevacuation lumen618, respectively, withinbody602, similar to the connection ofconnectors668 and669 to the lumen, as described below in the context ofFIG. 14D. In an alternative embodiment, the inventive electrocautery instruments can also be operated in a bipolar mode by connecting the instrument to the monopolar output of a commercially available monopolar power supply for use in electrocautery. In such embodiments,pressure lumen620, providing the positive electrode can be connected in electrical communication with the positive monopolar terminal of the power supply, whileevacuation lumen618, providing an electrode at ground potential, can be connected in electrical communication with the power supply's grounding connection. Also power supplied to the instrument from, for example,power supply636 for performing electrocautery may, in some embodiments, be user controllable via a switch or other means provided onpower supply636,body602, or via a remote switch, for example a foot operated switch, etc., as apparent to those of ordinary skill in the art.
• In the illustrated embodiment, the pressure and evacuation lumen are constructed from a conductive material, such as stainless steel, that has a relatively low resistance to electrical current flow. The insulating coating provided on the outer surfaces of the lumen as described can comprise any insulating coating known to those of ordinary skill in the art. In one preferred embodiment, the coating comprises a polymeric coating formed on the surfaces of the lumen as shown using commercially available shrink-wrap tubing, for example polyvinylidene fluoride (PVDF) shrink wrap tubing. In another embodiment, the insulating coating comprises a polymeric coating (e.g. PVDF) formed on the outer surface by a variety of well known coating methods, for example spray coating, brush coating. dip coating, etc. with a variety of commercially available polymer layer forming solutions as known in the art. In one preferred embodiment, the insulating layer formed onpressure lumen620 comprises a polymeric coating formed on the surface of the lumen using PVDF shrink-wrap tubing, while the insulating layer formed on the distal end ofevacuation lumen620 is formed by spray coating with a PVDF layer forming solution.
• The thickness of the electrical insulating layer should be chosen to prevent electrical conduction through the layer during operation at maximum expected operating potentials of the instrument. The thickness will depend upon the well known electrical properties of the particular type of commercially available electrical insulation chosen and can be readily determined by those of ordinary skill in the art. In one embodiment, PVDF shrink-wrap tubing having a thickness of between about 0.004 inch and about 0.006 inch is used as the electrical coating for an instrument having a 1,500 volt peak-to-peak rating.
• The distal end ofsurgical instrument600 is shown in greater detail inFIGS. 14B and 14C.FIGS. 14B and 14C also showsheath612 and rotatably mountedcollar610 in greater detail.Distal end608 ofsurgical instrument600 is shown inFIG. 14B in the undeployed position and inFIG. 14C in the deployed position. In the undeployed position,distal end608 has a cross-sectional dimension, length, and angular orientation θ with respect to the longitudinal axis of thesheath612 and the longitudinal axis of thebody602 ofinstrument600, which are selected to facilitate insertion ofdistal end608 into a confined surgical operating space, for example a joint capsule, for a particular surgical procedure. For example, for arthroscopy, at least one cross-sectional dimension ofdistal end608, when in the undeployed configuration, should be no greater than about 2.8 mm, the length ofdistal end608 is preferably between 10 and 15 mm, and angle θ is preferably about 15 degrees.Pressure lumen620 is fixably mounted withinbody602, so that it is essentially immobile with respect tobody602, and is rotatably mounted withinsheath612 and rotatably mountedcollar610 so that the sheath can rotate around the outer surface of the pressure lumen upon deployment ofdistal end608. By contrast,evacuation lumen618 is fixably mounted tosheath612 and/or rotatably mountedcollar610, but is rotatably moveable withinbody602 upon rotation of rotatably mountedcomponent610, so that rotation of rotatably mountedcollar610 andsheath612 causes a corresponding rotation ofevacuation lumen618 resulting in deployment ofdistal end608. Rotatably mountedcollar610 includes a slot or groove650 having alongitudinal axis652 that is non-parallel with respect to the longitudinal axis of rotatablymounted collar610 and the longitudinal axis ofbody602 ofinstrument600.Slot650 is used to create rotation of rotatably mountedcollar610 upon movement ofslidable sleeve606, as described in more detail below. Rotatably mountedcollar610 also includes a bearingflange654 which is mounted withinbody602 ofinstrument600 to allow for rotation ofcollar610, as described in more detail below. Deployment ofdistal end608, as shown inFIG. 14C, establishes a separation distance l between jet opening656 innozzle628 and jet-receivingopening658 at the distal end ofevacuation lumen618. Separation distance l defines a liquid jet path length, when the instrument is in operation. In certain preferred embodiments,axis660 which defines the direction of a central region of the liquid jet emitted from jet opening656 when the instrument is in operation, is non-parallel with respect to the longitudinal axes ofsheath612 andbody602 ofinstrument600. Typically, for such embodiments,axis660 forms an angle with respect to the longitudinal axis ofbody602 that is between about 45 and 115 degrees, more typically between about 80 and about 100 degrees, and most typically about 90 degrees.
• FIG. 14D shows a partially cutaway view ofsurgical instrument600 showing more clearly the proximal end ofbody602 and the connection ofpressure lumen620 to high pressureliquid supply conduit662 andevacuation lumen618 toevacuation conduit664.Pressure lumen620 can be connected to high pressureliquid supply conduit662 via any of a wide variety of highpressure tubing connectors667 well known in the art.Pressure lumen620 and/or high pressureliquid conduit662 are fixably mounted withinbody602 to prevent movement ofpressure lumen620 with respect tobody602 during deployment.Evacuation lumen618 rotates withinbody602 upon movement ofactuating element606.Evacuation lumen618 is connected toevacuation conduit664, which is flexible and/or twistable withinbody602, to allowevacuation lumen618 to rotate.
• FIG. 14D also illustrates one embodiment for providing electrical connections betweenpressure lumen620 andpositive jack640 and betweenevacuation lumen618 andground jack644 withinbody602.Positive jack640 is electrically connected to pressurelumen620 via a wire or otherelectrical connector668, andground jack644 is electrically connected toevacuation lumen618 via a wire or otherelectrical connector669. Wire/connector668 is, in turn, crimped to, soldered to, or otherwise connected in electrical contact (by any suitable means known to those of ordinary skill in the art) to an electrically conductive surface ofpressure lumen620 atpoint670; likewise, wire/connector669 is, in turn, crimped to, soldered to, or otherwise connected in electrical contact to an electrically conductive surface ofpressure lumen618 atpoint672. Either or both ofhigh pressure conduit662 andhigh pressure connector667 should be constructed from, or coated with, an electrically insulating material (e.g. a plastic material) to prevent exposure of an operator to electrical shock via contact with theregion674 of the high pressure conduit extending outside ofbody602.
• The actuating mechanism by which actuatingelement606 causes rotation of rotatably mountedcollar610 andsheath612, in order to deploydistal end608 ofinstrument600, is shown more clearly inFIGS. 14E and 14F. Referring toFIG. 14E, a cut away view ofactuating element606 is shown. Actuatingelement606 can be generally cylindrical in shape and includes twoapertures676 and678.Aperture676 is located on the proximal surface of actuatingelement606 and allows actuatingelement606 to accommodatebody602 ofinstrument600.Aperture678 is located on the distal surface of actuatingelement606 and has a circumference that is nearly equal or slightly greater than the outer circumference of rotatably mountedcollar610, thus allowing rotatably mountedcollar610 to pass through, and rotate within,aperture678.Bearing flange654 of rotatablymounted collar610 is rotatably mounted within bearingslots680 ofbody602. Shown inFIG. 14F, actuatingelement606 includes apin682 mounted withinaperture678. As shown more clearly inFIG. 14E, when assembled, pin682 fits withinslot650 of rotatablymounted collar610 so that as an operator slidesactuating element606 in the direction ofarrow684, pin682 slides forward inslot650 causing rotation of rotatably mountedcollar610 in the direction shown byarrow686, thus causing deployment of the distal end ofinstrument600.
• FIG. 15 illustrates a preferred method, according to the invention, for forming the nozzle shown above inFIGS. 14A and 14B for deployable liquid jet instruments having adjustable liquid jet cutting path lengths. Such instruments and nozzles are described in greater detail in commonly owned U.S. patent application Ser. No. 09/313,679.Step1 ofFIG. 15 entails providing atubular conduit700 for use in forming a pressure lumen. The tubular conduit is typically formed of a biocompatible metal such as surgical stainless steel and is selected to have a burst strength sufficient to withstand the contemplated liquid pressures (e.g., a burst strength of at least 50,000 psig).
• Step2 of the method comprises necking down an end ofconduit700 to form anecked region702 having a reduced cross-sectional area, which necked region tapers into ajet nozzle region704 having an essentially constant internal cross-sectional area.Jet nozzle region704 terminates at its distal end injet opening706.Necked region702 can be formed inconduit700 by a variety of means known in the art, for example by swaging, crimping, or hot-drawing the distal end ofconduit700 to formnecked region702 andjet nozzle region704. At the end ofStep2,pressure lumen conduit700 has an internal radius R,jet nozzle region704 has a minimum internal radius r, andjet nozzle region704 is essentially co-linear with theaxial center line706 of the tube comprising thepressure lumen700 outside ofnecked region702.
• Step3 of the method involves offsettingjet nozzle region704 with respect totube700 so that theaxial center line708 ofnozzle region704 is offset from theaxial center line710 oftube700 outside ofnecked region702, by a distance D=R−r, so that thejet nozzle region704 and thetubular conduit700 abut each other along at least oneline712 co-linear to an external surface oftubular conduit700.
• For embodiments where it is desired that at least a central region of the liquid jet emitted from jet opening706 be directed in an orientation that is not parallel withaxis710,jet nozzle region704 may be bent with respect toaxis710 as shown inoptional Step4. In typical embodiments,nozzle region704 is bent so that theaxial center line708 ofjet nozzle region704 forms an angle with respect toaxis710 that is between 45 degrees and 115 degrees, more typically between about 80 degrees and 100 degrees, and most typically about 90 degrees. Also preferablynozzle region704 is bent with respect totube700 so that essentially no portion ofjet nozzle region704 projects radially beyond a perimeter that is defined by an outer surface oftube700 outside ofnecked region702. In addition to providing a method for forming liquid jet nozzles that have a relatively large length to minimum diameter ratio and that are relatively easy and inexpensive to manufacture, the inventive method also provides a pressure lumen having a maximum cross-sectional profile that does not exceed the diameter of the tubing comprising the pressure lumen. In addition, the nozzles formed by the method outlined inFIG. 15 also advantageously provide improved efficiency for forming a liquid jet as a high pressure liquid streams through the nozzle. The efficiency of forming the liquid jet is improved over nozzle designs comprising, for example, a hole bored in the side of a lumen, due to the fact thatnecked region702 provides a smooth tapering flow path for the liquid flowing intonozzle region704, thus reducing turbulence, recirculating flow patterns, and friction at the jet nozzle inlet. This effect is known in the fluid mechanical arts as the “vena contracta” effect and can improve fluid flow efficiencies through nozzles by as much as 30%.
• FIGS. 16A and 16B illustrate asurgical instrument1000 including integrated bipolar electrocautery that is similar in configuration withsurgical instrument100 previously shown inFIG. 1 above. The integrated electrocautery configuration forinstrument1000 is similar to that described above forinstrument600 ofFIGS. 14A-14F, except that forinstrument1000, which includes a grindingburr122 located at thedistal end116 and including a liquid jet-driven rotatable rotor and rotatable shaft for rotating the grinding burr, it is preferable to utilize the liquid cuttingjet evacuation lumen120 as the lumen providingpositive electrode1002 at the distal end of the surgical instrument. It is preferred to utilizeevacuation lumen120 as the positive electrode insurgical instrument1000 becauseevacuation lumen120 is connected withinbody104 of the instrument to evacuationconduit connecting block176 which, in turn, is connected toevacuation conduits178, which extend from the proximal end of the surgical instrument. Evacuationconduit connecting block176 andconduits178 are constructed of electrically non-conductive polymeric materials that do not conduct electricity fromevacuation lumen120 to any surface of the instrument in contact with the user during operation. Conversely, cuttingjet pressure lumen118, which is connected withinbody104 in electrical communication withground terminal1004 ofexternal power supply1006, is connected viahigh pressure connector190 to liquidflow directing valve180. The high pressure connector and liquid flow directing valve, as well as highpressure tubing coupler186 and, in some embodiments,knobs197, may be constructed of conducting materials and could come in contact with an operator of the device during operation. Thus, it is important that such surfaces be maintained at ground potential during operation of the electrocautery electrodes of the device.
• External power supply1006 preferably comprises a radio frequency generator as previously described in the context ofFIG. 14A above.Positive terminal1008 ofpower supply1006 is in electrical communication withevacuation lumen120 viaelectrical connector1010,jack1012, andelectrical connector1014 withinbody104 of the instrument. Liquid cuttingjet pressure lumen118 is connected in electrical communication withground terminal1004 viaelectrical connector1016,jack1018, andelectrical connector1020 withinbody104 of the instrument.Jacks1012 and1018 as well asconnections1022 and1024 of the electrical conductors withinbody104 to the lumen can be essentially identical to those described above in the context ofsurgical instrument600 ofFIGS. 14A-14F. In some preferred embodiments,jacks1012 and1018 are eliminated, andconnectors1016 and1020 are connected directly topressure lumen118 andevacuation lumen120, respectively, withinbody104. Also, as described above, power supplied to the instrument frompower supply1006 for performing electrocautery may, in some embodiments, be user controllable via a switch or other means provided onpower supply1006,body104, or via a remote switch, for example a foot operated switch, etc., as apparent to those of ordinary skill in the art.
• Evacuation lumen120, in electrical communication withpositive terminal1008 ofexternal power supply1006, is preferably insulated with an essentiallycontinuous layer1009 of electrical insulation (shaded region) along its entire length except atdistal tip1002 which forms a positive electrocautery electrode, as was previously described above in the context ofpressure lumen620 ofinstrument600. In contrast toinstrument600 above, and as previously described, instead of the pressure lumen that forms a liquid cutting jet being configured to form the positive electrode, insystem1000, it is preferred thatevacuation lumen120 be so configured. The relative size of the integrated electrocautery electrodes insurgical instrument1000 and the electrically insulating coating used for insulating the lumen of the instrument are, in preferred embodiments, essentially the same as that previously described forinstrument600 shown inFIGS. 14A-14F.
• FIG. 16B shows thedistal end116 ofinstrument1000 submersed in an electrically conductive fluid in asurgical field1032.Evacuation lumen120 is coated with electrically insulatinglayer1009 except at its distal tip. The uncoated, uninsulateddistal tip1002 forms the positive integrated electrocautery electrode.Pressure lumen118, in the illustrated embodiment, is uninsulated except atdistal tip1030. In the illustrated embodiment,distal tip1030 ofpressure lumen118 is insulated (shaded region), as previously described above forevacuation lumen618 ofsurgical instrument600, in order to reduce any arcing, shorting, or burning of tissue that may be caused by providing a conductive path length that is too short. Upon operation of theelectrocautery electrode1002 current flows fromelectrode1002 and through the target tissue and electrically conductive fluid insurgical field1032 to a conducting surface at ground potential that is in electrical communication with the ground terminal of the power supply, for example theuninsulated surface1031 ofpressure lumen118, as well as other conducting surfaces withinsurgical field1032 that are in electrical communication with the pressure lumen, such as grindingburr122,burr tip support136,sheath132, etc.Instrument1000 could, in alternative embodiments, be connected to a power supply providing monopolar output for performing electrocautery, as was previously described forinstrument600. Also, in other embodiments, because the distal ends ofevacuation lumen120 andpressure lumen118 are maintained at an essentially constant separation distance during operation of the device, unlikedeployable device600 shown previously inFIGS. 14A-14F, insulatedtip1030 ofpressure lumen118 can be eliminated (i.e., the entirety of the external surface ofpressure lumen118 may be electrically conductive) without unduly affecting performance of electrocautery with the instrument.
• The inventive surgical instruments described herein enable the performance of a number of inventive surgical methods. For example, by utilizing the surgical instruments provided according to the invention, which provide both a liquid cutting jet and a rotatable component at the distal end of the instrument, surgical procedures may be performed involving both liquid jet cutting/ablating and other tasks that utilize or require rotation of a rotatable component in a surgical field, without the need for exchanging surgical instruments within the surgical field or providing multiple instruments to the surgical field. For example, the invention enables an operator of such an instrument to insert the surgical instrument into a surgical field of a patient, create a liquid cutting jet with the surgical instrument to cut or ablate a tissue or other material within the surgical field and also cause rotation of a rotatable component of the same surgical instrument within the surgical field to perform a desired surgical task, for example contacting the rotatable component with a tissue within the surgical field (e.g., bone tissue) and grinding, cutting, or ablating the tissue with a rotating surface of the rotatable component.
• In some preferred embodiments, a surgical instrument provided according to the invention, for examplesurgical instrument100 shown inFIG. 1, can be inserted into a surgical field endoscopically, for example via use of a trocar. In one particularly preferred embodiment, the surgical instruments are utilized within the joint capsule of a patient, for example in the knee or shoulder joint of a patient, for performing an arthroscopic surgical procedure. Utilizingsurgical instrument100, for example, further enables an operator of the instrument to perform surgical liquid jet cutting/ablating while evacuating debris and liquid created by the liquid cutting jet from the surgical field with the surgical instrument without the need for applying a source of external suction in fluid communication with the liquid cutting jet evacuation lumen of the instrument. Also, as discussed above, liquidflow directing valve180 enables a user ofsurgical instrument100 to selectively direct high pressure fluid to either perform liquid jet cutting with the instrument or to utilize the liquid jet-drive rotatable component of the instrument via manipulation of the valve. Alternatively, in some embodiments, the operator can also direct high pressure liquid to both create a liquid cutting jet and drive the liquid jet-drive rotatable component simultaneously in order to perform both liquid jet cutting and, for example grinding etc. with the rotatable component, at the same time.
• Furthermore, surgical instruments provided according to the invention that include integrated electrocautery also permit an operator of the instrument, in addition to the surgical tasks described above, to apply an electrical signal to an electrode of the same surgical instrument used for liquid jet cutting in order to cauterize tissue within the surgical field. In some embodiments, electrocautery may be performed as a separate and distinct step from either liquid jet cutting or utilization of a rotatable component of the instrument, or, in other embodiments, electrocautery may be performed simultaneously with the operation of the liquid cutting jet and/or rotatable component capabilities of the instrument. For example, by performing electrocautery while simultaneously controllably evacuating a portion of the liquid from a surgical field with an evacuation lumen of the surgical instrument, for example by applying suction to a sheath surrounding the rotatable shaft of the instrument or by operating a liquid cutting jet to create an evacuation via eductor pump action, an operator with visual access to the surgical field can be able to visualize a trail of blood (i.e., a blood stream flowing along a stream line from the site of a bleed to the inlet of the source of evacuation provided by the surgical instrument) and can stop the bleeding with the instrument before visualization of the entire surgical field is compromised (i.e., before the entire surgical field is rendered opaque due to the presence of blood therein). Upon visualizing the trail of blood during the operation of the instrument, the user can move the surgical instrument within the surgical field along the trail of blood towards the bleeding vessel, while continuously providing evacuation to the instrument. Upon reaching the site of bleeding, the operator can place an electrocautery electrode provided on the surgical instrument in proximity to the bleeding vessel and apply an electrical signal to the electrode to electrocauterize the bleeding vessel to stop the bleeding therefrom. Such a method is particularly useful for endoscopic surgical procedures, for example arthroscopy procedures in the joint capsule of a patient, where the surgical field is visually monitored with an endoscopic camera.
• While several embodiments of the invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and structures for performing the functions and/or obtaining the results or advantages described herein, and each of such variations or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art would readily appreciate that all parameters, dimensions, materials, configurations, etc. described herein are meant to be exemplary and that actual parameters, dimensions, materials, configurations, etc. will depend upon specific applications for which the teachings of the present invention are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described. The present invention is directed to each individual feature, system, material and/or method described herein. In addition, any combination of two or more such features, systems, materials and/or methods, provided that such features, systems, materials and/or methods are not mutually inconsistent, is included within the scope of the present invention. In the claims (as well as in the specification above), all transitional phrases or phrases of inclusion, such as “comprising,” “including,” “carrying,” “having” “containing,” “composed of,” “made of,” “formed of” and the like shall be interpreted to be open-ended, i.e. to mean “including but not limited to.” Only the transitional phrases or phrases of inclusion “consisting of” and “consisting essentially of” are to be interpreted as closed or semi-closed phrases, respectively.

Claims (20)

1-22. (canceled)

23. A device comprising:

a surgical instrument having a distal end adapted to perform a surgical procedure on a patient and a proximal end adapted to be controllable by an operator, the instrument including:

a first lumen constructed of an electrically conducting material providing a first liquid passageway between the distal end and the proximal end of the instrument; and

a second lumen constructed of an electrically conducting material providing a second liquid passageway between the distal end and the proximal end of the instrument,

the first lumen being connectable in electrical communication with a first electrical potential, and having an external surface, at at least the distal end of the instrument, which is inserted into a surgical field of a patient when the instrument is utilized for a surgical procedure, that is coated with an essentially continuous layer of electrical insulation and includes an uninsulated region at a distal end of the first lumen, which region at a distal end of the first lumen forms a first electrocautery electrode, and

the second lumen being connectable in electrical communication with a second electrical potential different from the first electrical potential, and having an external surface, at at least the distal end of the instrument, which is inserted into a surgical field of a patient when the instrument is utilized for a surgical procedure, that is electrically conductive, forming a second electrocautery electrode, except in a region at a distal end of the second lumen, which region at a distal end of the second lumen is coated with an essentially continuous layer of electrical insulation

24. The device as inclaim 23, wherein the first electrical potential is provided by a positive terminal of an external power supply and the second electrical potential is provided by a source of ground potential, so that the first electrocautery electrode acts as a positive electrocautery electrode and the second electrocautery electrode acts as a ground electrocautery electrode, when the instrument is in operation.

25. The device as inclaim 23, wherein at least one layer of electrical insulation is formed from poly(vinylidene fluoride) shrink-wrap tubing.

26. The device as inclaim 25, wherein the thickness of the layers of electrical insulation is between about 0.004 inch and between about 0.006 inch.

27. The device as inclaim 23, wherein the distal end of the second lumen is insulated from a distal-most end of the lumen to a distance, measured proximally from the distal-most end, of about 0.2 inch.

28. The device as inclaim 24, wherein the total surface area of the distal end of the instrument which is inserted into a surgical field and which is maintained at ground potential exceeds the total surface area of the positive electrocautery electrode formed on the first lumen by at least a factor of about 2.

29. The device as inclaim 28, wherein the total surface area of the distal end of the instrument which is inserted into a surgical field and which is maintained at ground potential exceeds the total surface area of the positive electrocautery electrode formed on the first lumen by at least a factor of about 5.

30. The device as inclaim 29, wherein the total surface area of the distal end of the instrument which is inserted into a surgical field and which is maintained at ground potential exceeds the total surface area of the positive electrocautery electrode formed on the first lumen by at least a factor of about 10.

31. The device as inclaim 24, wherein the positive electrocautery electrode formed on the first lumen has a total surface area of about 0.2 cm².

32. The device as inclaim 24, wherein the total surface area of the ground electrocautery electrode formed on the second lumen is sufficient to prevent boiling of any liquid contained in the surgical field of the patient, when the instrument is in operation.

33. The device as inclaim 32, wherein the ground electrocautery electrode formed on the second lumen has a total surface area of at least about 2 cm².

34. A method comprising:

inserting a surgical instrument into a surgical field of a patient;

creating a liquid cutting jet with the surgical instrument;

cutting or ablating a selected tissue of the patient with the liquid cutting jet;

applying an electrical signal to at least one electrode of the surgical instrument; and

cauterizing a tissue of the patient.

35. The method as inclaim 34, further comprising after the creating step, the step of:

directing the liquid cutting jet towards a jet-receiving opening in an evacuation lumen of the surgical instrument.

36. The method as inclaim 35, wherein at least one electrode comprises a distal surface of at least one of a pressure lumen and the evacuation lumen of the surgical instrument.

37. The method as inclaim 36, wherein in the applying step, a bipolar electrical signal is applied to two electrodes of the surgical instrument.

38. The method as inclaim 34, further comprising the steps of:

rotating a rotatable component of the surgical instrument;

contacting a rotating surface of the rotatable component with a second selected tissue; and

grinding, cutting, or abrading the second selected tissue with the rotating surface.

39. The method as inclaim 34, wherein the creating step is performed independently of the cauterizing step.

40. The method as inclaim 34, wherein the creating step and the cauterizing step are performed concurrently.

41-45. (canceled)

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