US20170258519A1

Movatterモバイル変換

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Publication number: US20170258519A1
Application number: US15/454,342
Authority: US
Inventors: Aaron GERMAIN; Kyle Klein; Steffan BENAMOU; Jeffrey Norton; Jacob Tonkel
Original assignee: Relign Corp
Current assignee: Relign Corp
Priority date: 2016-03-10
Filing date: 2017-03-09
Publication date: 2017-09-14
Also published as: US12167888B2; WO2017156335A1; US20210113262A1

Abstract

An electrosurgical probe can be detachably secured to a handpiece having a motor drive unit and an RF current contact. The electrosurgical probe includes an elongate shaft having a longitudinal axis, a distal dielectric tip, and a proximal hub which is detachably securable to the handpiece. A hook electrode is reciprocatably mounted in the distal dielectric tip, and an RF connector on the hub is couplable to the RF current contact in the handpiece when the hub is secured to the handpiece. A drive mechanism in the hub mechanically couples to the hook electrode, and drive mechanism engages a rotational component in the motor drive unit when the hub is secured to the handpiece. The drive mechanism converts rotational motion from the rotational component into axial reciprocation and transmits the axial reciprocation to the hook electrode to axially displace the hook electrode between a non-extended position and an extended position relative to the dielectric tip.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional application No. 62/306,516 (Attorney Docket No. 41879-715.101), filed on Mar. 10, 2016, provisional application No. 62/309,324 (Attorney Docket No. 41879-719.101), filed on Mar. 16, 2016, and provisional application No. 62/325,025 (Attorney Docket No. 41879-719.102), filed on Apr. 20, 2016, the full disclosures of which are incorporated herein by reference.

The disclosure of the present application is related to that of application Ser. No. 15/421,264 (Attorney Docket No. 41879-714.201), filed on Jan. 31, 2017, the full disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to arthroscopic tissue cutting and ablation devices by which anatomical tissues may be resected, ablated and removed from a joint or other site. More specifically, this invention relates to electrosurgical probes and methods for ablating and removing soft tissue.

In many arthroscopic procedures including subacromial decompression, anterior cruciate ligament reconstruction, and resection of the acromioclavicular joint, there is a need for cutting and removing and soft tissue. Currently, surgeons use arthroscopic shavers having rotational cutting surfaces to remove soft tissue in such procedures.

The need exists for arthroscopic instrument that remove soft tissue rapidly. Recently, arthroscopic surgical cutters capable of selectively removing both hard tissues and soft tissues have been developed. Such cutters are described in the following US Patent Publications which are commonly assigned with the present application: US20130253498; US20160113706; US20160346036 US20160157916; and US20160081737, the full disclosures of which are incorporated herein by reference.

While very effective, it would be desirable to provide arthroscopic surgical cutters and cutter systems as “reposable” devices with disposable cutting components and reusable, sterilizable handles. Preferably, the handles would incorporate as many of the high value system components as possible. Further preferably, the handle designs would have a minimum number of external connections to simplify sterilization and set-up. Still more preferably, the cutters and systems would allow for bipolar cutting as well as monopolar and mechanical (cutting blade) resection. In particular, it would be desirable to provide arthroscopic cutters having non-rotational cutters, such as axially reciprocating cutters and RF cutting wires, and cutters that can also operate in an ablation mode. At least some of these objectives will be met by the inventions described herein.

2. Description of the Background Art

U.S. Pat. No. 6,149,620 and U.S. Pat. No. 7,678,069 describe tools for the volumetric removal of soft tissue in the knee and elsewhere. Co-pending, commonly owned U.S. patent application Ser. No. 15/421,264 (Attorney Docket No. 41879-714.201), filed on Jan. 31, 2017, describes a tissue removal device which can remove tissue by cutting (resection) and/or by radiofrequency (RF) ablation. US 2008/0188848 describes an electrosurgical cutter with a handpiece and a removable cutter instrument. Other commonly assigned published US Patent Applications have been listed above, including US20130253498; US20160113706; US20160346036; US20160157916; and US20160081737.

SUMMARY OF THE INVENTION

The present invention provides apparatus such as electrosurgical probes. In exemplary embodiments, an electrosurgical probe comprises an elongated shaft assembly having a proximal end, a distal end, and a longitudinal axis. A distal housing is mounted on the distal end of the shaft and in one embodiment has a laterally open window, that is, a plane of the window is generally perpendicular to the longitudinal axis of the shaft. An interior channel extends axially through the shaft and extends through an interior of the housing to a window in the housing. An electrode member with an elongated edge which may be serrated extends longitudinally across the window and is configured to reciprocate the elongated edge longitudinally relative to the window.

In specific embodiments, the shaft may comprise an outer sleeve and an inner sleeve, and the distal housing may be a ceramic and is mounted on a distal end of the outer sleeve. The electrode member is mounted on a distal end of the inner sleeve, and the inner sleeve may be reciprocatably mounted in the outer sleeve. A proximal hub is attached to a proximal end of the outer sleeve and a sliding collar is coupled to a proximal end of the inner sleeve, the sliding collar being mounted and configured to axially reciprocate within the proximal hub while being restrained from rotation relative to the proximal hub. In particular examples, a rotating drive coupling is mounted to rotate in the proximal hub while being restrained from axially translating relative to the proximal hub. The rotating drive coupling can have a distal surface which engages a proximal surface on the sliding collar, and the distal and proximal surfaces may have cam surfaces or otherwise shaped so that rotation and/or rotational oscillation of the rotating coupling causes the sliding collar to axially reciprocate within the proximal hub which in turn will cause the elongate edge of the electrode member to axially reciprocate relative to the window in the distal housing.

While the dimensions and geometries of the probe are usually not critical, in specific designs, the electrode member may reciprocate with a stroke in a range from 0.01 mm and 10 mm, often being in a range between 0.1 mm and 5 mm. The elongate edge may be substantially flush with the circumference of the distance housing. Further, the electrode edges may be configured to extend over edges or the window during reciprocation.

The electrosurgical probes of the present invention may further comprise a handpiece and motor drive operatively coupled to the shaft and configured to axially reciprocate the electrode at high speed relative to the window to provide a method of dynamic ablation. Usually, a proximal hub is connected to the proximal end of the elongated shaft, and the handpiece and motor drive are detachably coupled to the proximal hub. A negative pressure source is provided for coupling through the handpiece and proximal hub to an interior channel of the shaft which communicates with the window in the distal housing. The motor drive is typically configured to axially reciprocate the electrode edge at a rate in a range from 1 Hz and 1,000 Hz.

The distal housing or tip is a ceramic and may have a variety of specific geometries, and in one embodiment is attached to the distal end of the shaft. The ceramic tip has an opening therein that typically defines a circular or flower-shaped window that communicates with an interior channel in the tip and the shaft. In specific embodiments, the reciprocating component carries an electrode member that has a L-shaped or hook geometry with an axial region extending through ceramic tip and is coupled to an elongate member disposed in the shaft and configured for reciprocation through the opening. The ceramic tip or housing may be mounted on a distal end of the outer sleeve and the hook electrode may be mounted or crimped to the distal end of the elongate member which is reciprocatably mounted in the outer

In a broad aspect, the present invention provides a method for ablating and/or resecting, cutting or slicing tissue. The method comprises engaging an electrode protruding from the housing against a surface of the tissue. An elongate edge of an electrode member may be reciprocated longitudinally to the window in a plane perpendicular to the plane of the window, and a radiofrequency current with a cutting waveform may be applied to the electrode member to dynamically ablate tissue and generate tissue debris. A vacuum may be applied to the interior channel in the housing to aspirate the tissue debris through window.

In some embodiments, the elongate edge of the electrode member may protrude beyond the plane of the housing, while in other embodiments the edge may be flushed with or recessed into the housing circumference. The electrode member is typically reciprocated at a rate in a range from 1 Hz and 1,000 Hz, usually between 1 Hz and 500 Hz.

In a first specific aspect, the present invention provides an electrosurgical probe for use with a handpiece having a motor drive unit and a radiofrequency (RF) current contact. The probe comprises an elongate shaft having a longitudinal axis, a distal dielectric tip, and a proximal hub configured to be detachably secured to the handpiece. An RF hook electrode may be reciprocatably mounted on or in the distal dielectric tip of the elongate shaft, and an RF connector on the hub is configured to couple to the RF current contact in the handpiece when the hub is secured to the handpiece. The hub of the probe further includes a drive mechanism which is mechanically coupled to the hook electrode. The drive mechanism is configured to engage a rotational component which is part of the motor drive unit when the hub is secured to the handpiece. Typically, the rotational component will be a rotating spindle of the type commonly found on electric motors, where the spindle drives or includes a mechanical coupler configured to releasably or detachably engage and mechanically couple to the drive mechanism of the probe. The drive mechanism in the hub of the probe is configured to convert rotational motion from the rotational component of the handpiece into axial reciprocation or translation (e.g., being a rotating cam assembly) and to transmit the axial reciprocation or translation to the hook electrode, resulting in axial displacement or shifting of the hook electrode between a non-extended position and an extended position relative to the dielectric tip of the elongate shaft.

In exemplary embodiments, the drive mechanism comprises a rod, tube, or other elongate member disposed in, on, or through the elongate shaft and has a distal end attached to the hook electrode. The drive mechanism includes a device or assembly, such as a rotatable cam assembly, located in the hub to receive rotational motion from the spindle or other rotational component of the motor drive unit. The cam or other assembly converts the rotational motion into axial reciprocation which is delivered to the elongate member and subsequently transmitted through the shaft.

In further exemplary embodiments of the electrosurgical probe, the elongate member may be electrically conductive and connected to deliver RF current from the RF connector in the hub to the RF electrode. For example, the elongate member may be an electrically conductive metal rod or tube which extends the entire length of the elongate shaft to provide an electrically conductive path from the RF connector on the hub to the hook electrode. In particular embodiments, a proximal portion of the elongate member extends through a central opening in the hub and an intermediate portion of the elongate member extends through a central lumen in the shaft. The hook electrode is then reciprocatably disposed in an opening in the dielectric tip. Typically, the central lumen in the shaft is configured to be connected to a negative pressure (vacuum or suction) source, and the hub is configured to connect the central lumen to the negative pressure source.

In more specific exemplary embodiments, the shaft comprises an outer tube having a longitudinal lumen and an inner member reciprocatably received in the longitudinal lumen of the outer tube. The distal dielectric tip is typically attached to a distal end of the outer tube and will have an opening which is contiguous with the longitudinal lumen of the outer tube. The hook electrode is attached to a distal end of the inner member so that the electrode can reciprocate within the inner member relative to the outer tube.

In some embodiments, the inner member may comprise a rod, and the hook electrode may comprise a bent wire attached to a distal end of the rod. In such cases, the longitudinal lumen of the outer member is configured to be connected to a negative pressure source. Often, a distal face of the dielectric distal tip may have a recess and a notch so that a lateral end of the bent wire of the hook electrode can be retracted into the recess and notch when the hook electrode is in its non-extended position.

In still further exemplary embodiments, the shaft may have at least one interior channel, and the dielectric distal tip may have at least one flow channel. Usually, the at least one interior channel and at least one flow channel are contiguous and configured to be connected to a negative pressure source to provide a continuous suction or vacuum path therethrough. Usually, at least one flow channel will have a cross-sectional area of at least 0.001 in². The cross-sectional area of the at least one flow channel is typically configured to accommodate fluid outflows of at least 50 ml/min when the at least one interior channel and the at least one flow channel are connected to the negative pressure source. In certain embodiments, the at least one flow channel comprises a portion of an opening in the dielectric distal tip which receives the hook electrode. In other embodiments, the distal electric tip may have at least one opening to receive the hook electrode and in additional have one flow channel.

In still further exemplary embodiments, the distal electrode tip includes at least one opening to receive the hook electrode. The at least one opening which receives the hook electrode is usually (i) shaped with a plurality of support elements adapted or configured to support elongate member and/or (ii) includes a plurality of flow channels adapted or configured to provide fluid flow in response to suction from the negative pressure source. In such embodiments, there will typically be at least three support elements, sometimes being four or more support elements, and the dielectric tip typically comprises a ceramic material.

In a second specific aspect, the present invention provides an electrosurgical system comprising an electrosurgical probe and a handpiece configured to be detachably connected to the electrosurgical probe. The electrosurgical probe may have any of the configurations, components, and designs described previously and elsewhere herein. The handpiece will be configured to detachably connect to the hub on the electrosurgical probe, and the handpiece will include a motor drive unit which is configured to mechanically couple to the drive mechanism of the electrosurgical probe in order to longitudinally reciprocate the elongate member and hook electrode between non-extended positions and extended positions when the hub is secured to the handpiece.

In exemplary embodiments, the systems of the present invention may further comprise a controller configured to activate and de-activate (energize and de-energize), the motor drive unit in order to shift the elongate member and hook electrode between the non-extended position and the extended position relative to the dielectric trip. Usually, the controller will be further configured to deliver RF current to the electrode. The RF current may be delivered only when the electrode is in its extended position or may be delivered only when it's in the retracted condition, or still further at all times while the electrode is being reciprocated. The RF current may have a waveform selected for any known surgical purpose, for example cutting wave forms, coagulation wave forms, and the like.

In still further specific embodiments, the controller may be configured to longitudinally reciprocate the elongate member while simultaneously delivering RF current to the hook electrode. In other embodiments, the hook electrode may be further optionally configured to rotate or rotationally oscillate the hook electrode, either with or without the simultaneous delivery of RF current. More usually, however, the hook electrodes will be axially reciprocated with no rotational and/or oscillational motion.

The drive mechanism, motor drive unit, controller, and other components of the systems in the present invention may be configured to reciprocate the hook electrode over a distance in the range from 0.01 mm to 5 mm, usually between 0.1 mm and 4 mm. The controller and motor drive unit may be further configured to reciprocate the hook electrode at a rate in the range from 5 Hz to 500 Hz, usually at a rate in the range from 10 Hz to 100 Hz.

In a third specific aspect, the present invention provides methods for assembling an electrosurgical probe system. The methods comprise providing a first electrosurgical probe, providing a handpiece, and removably attaching a hub on the first electrosurgical probe to the handpiece. Attaching the hub to the probe causes mechanical attachment of a motor drive unit in the handpiece to a drive mechanism in the electrosurgical probe. The drive mechanism in the probe longitudinally reciprocates the elongate member in the probe to in turn reciprocate an RF electrode located at a distal end of the elongate member between a non-extended position and an extended position.

Removably attaching the hub on the electrosurgical probe to the first handpiece will usually also couple or otherwise connect an RF connector on the hub to the RF current contact on the first handpiece. The assembly methods may further comprise detaching the first electrosurgical probe from the handpiece after the electrosurgical probe system has been used to treat a patient. In some cases, after the first electrosurgical probe has been removed, the hub on a second different probe can then be removably attached to the handpiece and used to treat the patient.

In a fourth aspect, the present invention provides a method for electrosurgically resecting tissue. The method comprises positioning a distal tip of a shaft having a longitudinal axis at a tissue target site. By placing the distal tip of the shaft adjacent to the target tissue and rotating a motor in the handpiece, the hook electrode can be axially reciprocated at the distal tip of the shaft. The hook electrode typically is shifted between an axially non-extended or partially extended position and an axially extended position relative to the dielectric tip. By engaging the hook electrode against the target tissue, and delivering RF current through the hook electrode to the target tissue engaged by the electrode, the tissue may be resected, ablated, coagulated, or the like.

In some specific embodiments, the motor is driven only enough to move the hook electrode to a stationary position, typically either a fully extended position or a fully retracted position. Alternatively, the motor and handpiece may be run continuously in order to effect tissue resection as the RF electrode acts as a cutting blade when the probe is advanced through tissue. In all cases, a negative pressure will usually be drawn through an interior lumen of the shaft to aspirate a region around the target tissue where the resection, ablation, or the like is being effected.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be discussed with reference to the appended drawings. It should be appreciated that the drawings depict only typical embodiments of the invention and are therefore not to be considered limiting in scope.

FIG. 1 is a perspective view of a disposable arthroscopic cutter or burr assembly with a ceramic cutting member carried at the distal end of a rotatable inner sleeve with a window in the cutting member proximal to the cutting edges of the burr.

FIG. 2 is an enlarged perspective view of the ceramic cutting member of the arthroscopic cutter or burr assembly ofFIG. 1.

FIG. 3 is a perspective view of a handle body with a motor drive unit to which the burr assembly ofFIG. 1 can be coupled, with the handle body including an LCD screen for displaying operating parameters of device during use together with a joystick and mode control actuators on the handle.

FIG. 4 is an enlarged perspective view of the ceramic cutting member showing a manner of coupling the cutter to a distal end of the inner sleeve of the burr assembly.

FIG. 5A is a cross-sectional taken along line5A-5A ofFIG. 2 showing the close tolerance between sharp cutting edges of a window in a ceramic cutting member and sharp lateral edges of the outer sleeve which provides a scissor-like cutting effect in soft tissue.

FIG. 5B is a cross-sectional view similar toFIG. 5A with the ceramic cutting member in a different rotational position than inFIG. 5A.

FIG. 6 is a perspective view of another ceramic cutting member carried at the distal end of an inner sleeve with a somewhat rounded distal nose and deeper flutes than the cutting member ofFIGS. 2 and 4, and with aspiration openings or ports formed in the flutes.

FIG. 7 is a perspective view of another ceramic cutting member with cutting edges that extend around a distal nose of the cutter together with an aspiration window in the shaft portion and aspiration openings in the flutes.

FIG. 8 is a perspective view of a ceramic housing carried at the distal end of the outer sleeve.

FIG. 9 is a perspective of another variation of a ceramic member with cutting edges that includes an aspiration window and an electrode arrangement positioned distal to the window.

FIG. 10 is an elevational view of a ceramic member and shaft ofFIG. 9 showing the width and position of the electrode arrangement in relation to the window.

FIG. 11 is an end view of the ceramic member ofFIGS. 9-10 the outward periphery of the electrode arrangement in relation to the rotational periphery of the cutting edges of the ceramic member.

FIG. 12A is a schematic view of the working end and ceramic cutting member ofFIGS. 9-11 illustrating a step in a method of use.

FIG. 12B is another view of the working end ofFIG. 12A illustrating a subsequent step in a method of use to ablate a tissue surface.

FIG. 12C is a view of the working end ofFIG. 12A illustrating a method of tissue resection and aspiration of tissue chips to rapidly remove volumes of tissue.

FIG. 13A is an elevational view of an alternative ceramic member and shaft similar to that ofFIG. 9 illustrating an electrode variation.

FIG. 13B is an elevational view of another ceramic member similar to that ofFIG. 12A illustrating another electrode variation.

FIG. 13C is an elevational view of another ceramic member similar to that ofFIGS. 12A-12B illustrating another electrode variation.

FIG. 14 is a perspective view of an alternative working end and ceramic cutting member with an electrode partly encircling a distal portion of an aspiration window.

FIG. 15A is an elevational view of a working end variation with an electrode arrangement partly encircling a distal end of the aspiration window.

FIG. 15B is an elevational view of another working end variation with an electrode positioned adjacent a distal end of the aspiration window.

FIG. 16 is a perspective view of a variation of a working end and ceramic member with an electrode adjacent a distal end of an aspiration window having a sharp lateral edge for cutting tissue.

FIG. 17 is a perspective view of a variation of a working end and ceramic member with four cutting edges and an electrode adjacent a distal end of an aspiration window.

FIG. 18 is a perspective view of a variation of another type of electrosurgical ablation device that can be detachably coupled to a handpiece as shown inFIG. 23.

FIG. 19A is a perspective view of the working end and ceramic housing of the device ofFIG. 18 showing an electrode in a first position relative to a side-facing window.

FIG. 19B is a perspective view of the working end ofFIG. 19A showing the electrode in a second position relative to the window.

FIG. 20A is a sectional view of the working end and electrode ofFIG. 19A.

FIG. 20B is a sectional view of the working end and electrode ofFIG. 19B.

FIG. 21A is a sectional view of the hub of the probe ofFIG. 18 taken along line21A-21A ofFIG. 18 showing an actuation mechanism in a first position.

FIG. 21B is a sectional view of the hub ofFIG. 21A showing the actuation mechanism in a second position.

FIG. 22 is a sectional view of the hub ofFIG. 21A rotated 90° to illustrate electrical contacts and pathways in the hub.

FIG. 23 is a schematic diagram of as RF system that includes a controller console, handpiece with a motor drive and a footswitch.

FIG. 24 is a perspective view of the RF probe ofFIG. 18 from a different angle showing the drive coupling.

FIG. 25 is a perspective view is a perspective view of a variation of another type of electrosurgical ablation device that can be detachably coupled to a handpiece as shown inFIG. 23, which has a hook type electrode that is moveable with a motor drive.

FIG. 26A is a perspective view of the working end of the probeFIG. 25 with the hook electrode in a non-extended position relative to a dielectric distal tip.

FIG. 26B is a view of the working end ofFIG. 26A with the hook electrode in an extended position.

FIG. 27 is a sectional view of the working end ofFIG. 26B with the hook electrode in an extended position.

FIG. 28 is a sectional view of the dielectric tip ofFIGS. 26A-27 with the hook electrode removed to show the fluid flow channels therein.

FIG. 29 is an end view of an alternative dielectric tip similar to that ofFIGS. 26A-28 with a different configuration of fluid flow channels therein.

FIG. 30 is an end view of another dielectric tip with a different configuration of fluid flow channels.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to devices for cutting, ablating and removing bone and soft tissue and related methods of use. Several variations of the invention will now be described to provide an overall understanding of the principles of the form, function and methods of use of the devices disclosed herein. In one variation, the present disclosure provides for an arthroscopic cutter or burr assembly for cutting or abrading bone that is disposable and is configured for detachable coupling to a non-disposable handle and motor drive component. This description of the general principles of this invention is not meant to limit the inventive concepts in the appended claims.

In general, one embodiment provides a high-speed rotating ceramic cutter or burr that is configured for use in many arthroscopic surgical applications, including but not limited to treating bone in shoulders, knees, hips, wrists, ankles and the spine. More in particular, the device includes a cutting member that is fabricated entirely of a ceramic material that is extremely hard and durable, as described in detail below. A motor drive is operatively coupled to the ceramic cutter to rotate the burr edges at speeds ranging from 3,000 RPM to 20,000 RPM.

In one variation shown inFIGS. 1-2, an arthroscopic cutter orburr assembly100 is provided for cutting and removing hard tissue, which operates in a manner similar to commercially available metals shavers and burrs.FIG. 1 showsdisposable burr assembly100 that is adapted for detachable coupling to ahandle104 andmotor drive unit105 therein as shown inFIG. 3.

Thecutter assembly100 has ashaft110 extending alonglongitudinal axis115 that comprises anouter sleeve120 and aninner sleeve122 rotatably disposed therein with theinner sleeve122 carrying a distalceramic cutting member125. Theshaft110 extends from aproximal hub assembly128 wherein theouter sleeve120 is coupled in a fixed manner to anouter hub140A which can be an injection molded plastic, for example, with theouter sleeve120 insert molded therein. Theinner sleeve122 is coupled to an inner hub140B (phantom view) that is configured for coupling to the motor drive unit105 (FIG. 3). The outer andinner sleeves120

ands

122 typically can be a thin wall stainless steel tube, but other materials can be used such as ceramics, metals, plastics or combinations thereof.

Referring toFIG. 2, theouter sleeve120 extends todistal sleeve region142 that has an open end and cut-out144 that is adapted to expose awindow145 in theceramic cutting member125 during a portion of the inner sleeve's rotation. Referring toFIGS. 1 and 3, theproximal hub128 of theburr assembly100 is configured with a J-lock, snap-fit feature, screw thread or other suitable feature for detachably locking thehub assembly128 into thehandle104. As can be seen inFIG. 1, theouter hub140A includes a projecting key146 that is adapted to mate with a receiving J-lock slot148 in the handle104 (seeFIG. 3).

InFIG. 3, it can be seen that thehandle104 is operatively coupled byelectrical cable152 to acontroller155 which controls themotor drive unit105. Actuator buttons156a,156bor156con thehandle104 can be used to select operating modes, such as various rotational modes for the ceramic cutting member. In one variation, a joystick158 may be moved forward and backward to adjust the rotational speed of theceramic cutting member125. The rotational speed of the cutter can continuously adjustable, or can be adjusted in increments up to 20,000 RPM.FIG. 3 further shows thatnegative pressure source160 is coupled to aspiration tubing162 which communicates with a flow channel in thehandle104 andlumen165 ininner sleeve122 which extends towindow145 in the ceramic cutting member125 (FIG. 2).

Now referring toFIGS. 2 and 4, the cuttingmember125 comprises a ceramic body or monolith that is fabricated entirely of a technical ceramic material that has a very high hardness rating and a high fracture toughness rating, where “hardness” is measured on a Vickers scale and “fracture toughness” is measured in MPam^1/2. Fracture toughness refers to a property which describes the ability of a material containing a flaw or crack to resist further fracture and expresses a material's resistance to brittle fracture. The occurrence of flaws is not completely avoidable in the fabrication and processing of any components.

The authors evaluated technical ceramic materials and tested prototypes to determine which ceramics are best suited for thenon-metal cutting member125. When comparing the material hardness of the ceramic cutters of the invention to prior art metal cutters, it can easily be understood why typical stainless steel bone burrs are not optimal. Types 304 and 316 stainless steel have hardness ratings of 1.7 and 2.1, respectively, which is low and a fracture toughness ratings of 228 and 278, respectively, which is very high. Human bone has a hardness rating of 0.8, so a stainless steel cutter is only about 2.5 times harder than bone. The high fracture toughness of stainless steel provides ductile behavior which results in rapid cleaving and wear on sharp edges of a stainless steel cutting member. In contrast, technical ceramic materials have a hardness ranging from approximately 10 to 15, which is five to six times greater than stainless steel and which is 10 to 15 times harder than cortical bone. As a result, the sharp cutting edges of a ceramic remain sharp and will not become dull when cutting bone. The fracture toughness of suitable ceramics ranges from about 5 to 13 which is sufficient to prevent any fracturing or chipping of the ceramic cutting edges. The authors determined that a hardness-to-fracture toughness ratio (“hardness-toughness ratio”) is a useful term for characterizing ceramic materials that are suitable for the invention as can be understood form the Chart A below, which lists hardness and fracture toughness of cortical bone, a 304 stainless steel, and several technical ceramic materials.

CHART A

Hard-	Fracture	Ratio Hard-
ness	Toughness	ness to Frac-
(GPa)	(MPam^1/2)	ture Toughness

Cortical bone	0.8	12	.07:1
Stainless steel 304	2.1	228	.01:1
Yttria-stabilized zirconia (YTZP)
YTZP 2000	12.5	10	1.25:1
(Superior Technical Ceramics)
YTZP 4000	12.5	10	1.25:1
(Superior Technical Ceramics)
YTZP (CoorsTek)	13.0	13	1.00:1
Magnesia stabilized zirconia (MSZ)
Dura-Z ®	12.0	11	1.09:1
(Superior Technical Ceramics)
MSZ 200 (CoorsTek)	11.7	12	0.98:1
Zirconia toughened alumina (ZTA)
YTA-14	14.0	5	2.80:1
(Superior Technical Ceramics)
ZTA (CoorsTek)	14.8	6	2.47:1
Ceria stabilized zirconia
CSZ (Superior Technical Ceramics)	11.7	12	0.98:1
Silicon Nitride
SiN (Superior Technical Ceramics)	15.0	6	2.50:1

As can be seen in Chart A, the hardness-toughness ratio for the listed ceramic materials ranges from 98× to 250× greater than the hardness-toughness ratio for stainless steel 304. In one aspect of the invention, a ceramic cutter for cutting hard tissue is provided that has a hardness-toughness ratio of at least 0.5:1, 0.8:1 or 1:1.

In one variation, theceramic cutting member125 is a form of zirconia. Zirconia-based ceramics have been widely used in dentistry and such materials were derived from structural ceramics used in aerospace and military armor. Such ceramics were modified to meet the additional requirements of biocompatibility and are doped with stabilizers to achieve high strength and fracture toughness. The types of ceramics used in the current invention have been used in dental implants, and technical details of such zirconia-based ceramics can be found in Volpato, et al., “Application of Zirconia in Dentistry: Biological, Mechanical and Optical Considerations”, Chapter 17 inAdvances in Ceramics—Electric and Magnetic Ceramics, Bioceramics, Ceramics and Environment(2011).

In one variation, theceramic cutting member125 is fabricated of an yttria-stabilized zirconia as is known in the field of technical ceramics, and can be provided by CoorsTek Inc., 16000 Table Mountain Pkwy., Golden, Colo. 80403 or Superior Technical Ceramics Corp., 600 Industrial Park Rd., St. Albans City, Vt. 05478. Other technical ceramics that may be used consist of magnesia-stabilized zirconia, ceria-stabilized zirconia, zirconia toughened alumina and silicon nitride. In general, in one aspect of the invention, the monolithicceramic cutting member125 has a hardness rating of at least 8 Gpa (kg/mm²). In another aspect of the invention, theceramic cutting member125 has a fracture toughness of at least 2 MPam^1/2.

The fabrication of such ceramics or monoblock components are known in the art of technical ceramics, but have not been used in the field of arthroscopic or endoscopic cutting or resecting devices. Ceramic part fabrication includes molding, sintering and then heating the molded part at high temperatures over precise time intervals to transform a compressed ceramic powder into a ceramic monoblock which can provide the hardness range and fracture toughness range as described above. In one variation, the molded ceramic member part can have additional strengthening through hot isostatic pressing of the part. Following the ceramic fabrication process, a subsequent grinding process optionally may be used to sharpen the cutting edges175 of the burr (seeFIGS. 2 and 4).

InFIG. 4, it can be seen that in one variation, theproximal shaft portion176 of cuttingmember125 includes projectingelements177 which are engaged by receivingopenings178 in a stainless steel split collar180 shown in phantom view. The split collar180 can be attached around theshaft portion176 and projectingelements177 and then laser welded alongweld line182. Thereafter,proximal end184 of collar180 can be laser welded to thedistal end186 of stainless steelinner sleeve122 to mechanically couple theceramic body125 to the metalinner sleeve122. In another aspect of the invention, the ceramic material is selected to have a coefficient of thermal expansion between is less than 10 (1×10⁶/° C.) which can be close enough to the coefficient of thermal expansion of themetal sleeve122 so that thermal stresses will be reduced in the mechanical coupling of theceramic member125 andsleeve122 as just described. In another variation, a ceramic cutting member can be coupled tometal sleeve122 by brazing, adhesives, threads or a combination thereof.

Referring toFIGS. 1 and 4, theceramic cutting member125 haswindow145 therein which can extend over a radial angle of about 10° to 90° of the cutting member's shaft. In the variation ofFIG. 1, the window is positioned proximally to the cutting edges175, but in other variations, one or more windows or openings can be provided and such openings can extend in the flutes190 (seeFIG. 6) intermediate the cutting edges175 or around a rounded distal nose of theceramic cutting member125. The length L ofwindow145 can range from 2 mm to 10 mm depending on the diameter and design of theceramic member125, with a width W of 1 mm to 10 mm.

FIGS. 1 and 4 shows the ceramic burr or cuttingmember125 with a plurality ofsharp cutting edges175 which can extend helically, axially, longitudinally or in a cross-hatched configuration around the cutting member, or any combination thereof. The number of cuttingedges175 andsintermediate flutes190 can range from 2 to 100 with a flute depth ranging from 0.10 mm to 2.5 mm. In the variation shown inFIGS. 2 and 4, the outer surface or periphery of the cutting edges175 is cylindrical, but such a surface or periphery can be angled relative toaxis115 or rounded as shown inFIGS. 6 and 7. The axial length AL of the cutting edges can range between 1 mm and 10 mm. While the cuttingedges175 as depicted inFIG. 4 are configured for optimal bone cutting or abrading in a single direction of rotation, it should be appreciated the that thecontroller155 andmotor drive105 can be adapted to rotate theceramic cutting member125 in either rotational direction, or oscillate the cutting member back and forth in opposing rotational directions.

FIGS. 5A-5B illustrate a sectional view of thewindow145 andshaft portion176 of aceramic cutting member125′ that is very similar to theceramic member125 ofFIGS. 2 and 4. In this variation, the ceramic cutting member haswindow145 with one or both lateral sides configured with sharp cutting edges202aand202bwhich are adapted to resect tissue when rotated or oscillated within close proximity, or in scissor-like contact with, the lateral edges204aand204bof the sleeve walls in the cut-outportion144 of the distal end of outer sleeve120 (seeFIG. 2). Thus, in general, the sharp edges ofwindow145 can function as a cutter or shaver for resecting soft tissue rather than hard tissue or bone. In this variation, there is effectively no open gap G between the sharp edges202aand202bof theceramic cutting member125′ and the sharp lateral edges204a,204bof thesleeve120. In another variation, the gap G between the window cutting edges202a,202band the sleeve edges204a,204bis less than about 0.020″, or less than 0.010″.

FIG. 6 illustrates another variation of ceramic cuttingmember225 coupled to aninner sleeve122 in phantom view. The ceramic cutting member again has a plurality ofsharp cutting edges175 andflutes190 therebetween. Theouter sleeve120 and its distal opening and cut-outshape144 are also shown in phantom view. In this variation, a plurality of windows oropening245 are formed within theflutes190 and communicate with theinterior aspiration channel165 in the ceramic member as described previously.

FIG. 7 illustrates another variation of ceramic cutting member250 coupled to an inner sleeve122 (phantom view) with the outer sleeve not shown. The ceramic cutting member250 is very similar to theceramic cutter125 ofFIGS. 1, 2 and 4, and again has a plurality ofsharp cutting edges175 andflutes190 therebetween. In this variation, a plurality of windows or opening255 are formed in theflutes190 intermediate the cutting edges175 and anotherwindow145 is provided in ashaft portion176 ofceramic member225 as described previously. The openings255 andwindow145 communicate with theinterior aspiration channel165 in the ceramic member as described above.

It can be understood that the ceramic cutting members can eliminate the possibility of leaving metal particles in a treatment site. In one aspect of the invention, a method of preventing foreign particle induced inflammation in a bone treatment site comprises providing a rotatable cutter fabricated of a ceramic material having a hardness of at least 8 Gpa (kg/mm²) and/or a fracture toughness of at least 2 MPam^1/2and rotating the cutter to cut bone without leaving any foreign particles in the treatment site. The method includes removing the cut bone tissue from the treatment site through an aspiration channel in a cutting assembly.

FIG. 8 illustrates variation of an outer sleeve assembly with the rotating ceramic cutter and inner sleeve not shown. In the previous variations, such as inFIGS. 1, 2 and 6,shaft portion176 of theceramic cutter125 rotates in a metalouter sleeve120.FIG. 8 illustrates another variation in which a ceramic cutter (not shown) would rotate in a ceramic housing280. In this variation, the shaft or a ceramic cutter would thus rotate is a similar ceramic body which may be advantageous when operating a ceramic cutter at high rotational speeds. As can be seen inFIG. 8, a metal distal metal housing282 is welded to theouter sleeve120 along weld line288. The distal metal housing282 is shaped to support and provide strength to the inner ceramic housing282.

FIGS. 9-11 are views of an alternative tissue resecting assembly or workingend400 that includes aceramic member405 with cuttingedges410 in a form similar to that described previously.FIG. 9 illustrates the monolithicceramic member405 carried as a distal tip of a shaft orinner sleeve412 as described in previous embodiments. Theceramic member405 again has awindow415 that communicates withaspiration channel420 inshaft412 that is connected tonegative pressure source160 as described previously. Theinner sleeve412 is operatively coupled to amotor drive105 and rotates in anouter sleeve422 of the type shown inFIG. 2. Theouter sleeve422 is shown inFIG. 10.

In the variation illustrated inFIG. 9, theceramic member405 carries anelectrode arrangement425, or active electrode, having a single polarity that is operatively connected to anRF source440. A return electrode, orsecond polarity electrode430, is provided on theouter sleeve422 as shown inFIG. 10. In one variation, theouter sleeve422 can comprise an electrically conductive material such as stainless steel to thereby function as return electrode445, with a distal portion ofouter sleeve422 is optionally covered by athin insulative layer448 such as parylene, to space apart theactive electrode425 from thereturn electrode430.

Theactive electrode arrangement425 can consist of a single conductive metal element or a plurality of metal elements as shown inFIGS. 9 and 10. In one variation shown inFIG. 9, the plurality of electrode elements450a,450band450cextend transverse to thelongitudinal axis115 ofceramic member405 andinner sleeve412 and are slightly spaced apart in the ceramic member. In one variation shown inFIGS. 9 and 10, theactive electrode425 is spaced distance D from the distal edge452 ofwindow415 which is less than 5 mm and often less than 2 mm for reasons described below. The width W and length L ofwindow415 can be the same as described in a previous embodiment with reference toFIG. 4.

As can be seen inFIGS. 9 and 11, theelectrode arrangement425 is carried intermediate the cutting edges410 of theceramic member405 in a flattenedregion454 where the cuttingedges410 have been removed. As can be best understood fromFIG. 11, theouter periphery455 ofactive electrode425 is within the cylindrical or rotational periphery of the cuttingedges410 when they rotate. InFIG. 11, the rotational periphery of the cutting edges is indicated at460. The purpose of the electrode'souter periphery455 being equal to, or inward from, the cuttingedge periphery460 during rotation is to allow the cutting edges410 to rotate at high RPMs to engage and cut bone or other hard tissue without the surface or theelectrode425 contacting the targeted tissue.

FIG. 9 further illustrates a method of fabricating theceramic member405 with theelectrode arrangement425 carried therein. The moldedceramic member405 is fabricated withslots462 that receive theelectrode elements450a-450c, with the electrode elements fabricated from stainless steel, tungsten or a similar conductive material. Eachelectrode element450a-450chas abore464 extending therethrough for receiving an elongatedwire electrode element465. As can be seen inFIG. 9, and theelongated wire electrode465 can be inserted from the distal end of theceramic member405 through a channel in theceramic member405 and through thebores464 in theelectrode elements450a-450c. Thewire electrode465 can extend through theshaft412 and is coupled to theRF source440. Thewire electrode element465 thus can be used as a means of mechanically locking theelectrode elements450a-450cinslots462 and also as a means to deliver RF energy to theelectrode425.

Another aspect of the invention is illustrated inFIGS. 9-10 wherein it can be seen that theelectrode arrangement425 has a transverse dimension TD relative toaxis115 that is substantial in comparison to the window width W as depicted inFIG. 10. In one variation, the electrode's transverse dimension TD is at least 50% of the window width W, or the transverse dimension TD is at least 80% of the window width W. In the variation ofFIGS. 9-10, the electrode transverse dimension TD is 100% or more of the window width W. It has been found that tissue debris and byproducts from RF ablation are better captured and extracted by awindow415 that is wide when compared to the width of the RF plasma ablation being performed.

In general, the tissue resecting system comprises an elongated shaft with a distal tip comprising a ceramic member, a window in the ceramic member connected to an interior channel in the shaft and an electrode arrangement in the ceramic member positioned distal to the window and having a width that is at 50% of the width of the window, at 80% of the width of the window or at 100% of the width of the window. Further, the system includes anegative pressure source160 in communication with theinterior channel420.

Now turning toFIGS. 12A-12C, a method of use of the resectingassembly400 ofFIG. 9 can be explained. InFIG. 12A, the system and a controller is operated to stop rotation of theceramic member405 in a selected position were thewindow415 is exposed in the cut-out482 of the open end ofouter sleeve422 shown in phantom view. In one variation, a controller algorithm can be adapted to stop the rotation of the ceramic405 that uses a Hall sensor484ain the handle104 (seeFIG. 3) that senses the rotation of a magnet484bcarried by inner sleeve hub140B as shown inFIG. 2. The controller algorithm can receive signals from the Hall sensor which indicated the rotational position of theinner sleeve412 and ceramic member relative to theouter sleeve422. The magnet484bcan be positioned in the hub140B (FIG. 2) so that when sensed by the Hall sensor, the controller algorithm can de-activate themotor drive105 so as to stop the rotation of the inner sleeve in the selected position.

Under endoscopic vision, referring toFIG. 12B, the physician then can position theelectrode arrangement425 in contact with tissue targeted T for ablation and removal in a working space filled withfluid486, such as a saline solution which enables RF plasma creation about the electrode. Thenegative pressure source160 is activated prior to or contemporaneously with the step of delivering RF energy toelectrode425. Still referring toFIG. 12B, when theceramic member405 is positioned in contact with tissue and translated in the direction of arrow Z, thenegative pressure source160 suctions the targeted tissue into thewindow415. At the same time, RF energy delivered toelectrode arrangement425 creates a plasma P as is known in the art to thereby ablate tissue. The ablation then will be very close to thewindow415 so that tissue debris, fragments, detritus and byproducts will be aspirated along withfluid486 through thewindow415 and outwardly through theinterior extraction channel420 to a collection reservoir. In one method shown schematically inFIG. 12B, a light movement or translation ofelectrode arrangement425 over the targeted tissue will ablate a surface layer of the tissue and aspirate away the tissue detritus.

FIG. 12C schematically illustrates a variation of a method which is of particular interest. It has been found if suitable downward pressure on the workingend400 is provided, then axial translation of workingend400 in the direction arrow Z inFIG. 12C, together with suitable negative pressure and the RF energy delivery will cause the plasma P to undercut the targeted tissue along line L that is suctioned intowindow415 and then cut and scoop out a tissue chips indicated at488. In effect, the workingend400 then can function more as a high volume tissue resecting device instead of, or in addition to, its ability to function as a surface ablation tool. In this method, the cutting or scooping ofsuch tissue chips488 would allow the chips to be entrained in outflows offluid486 and aspirated through theextraction channel420. It has been found that this system with an outer shaft diameter of 7.5 mm, can perform a method of the invention can ablate, resect and remove tissue greater than 15 grams/min, greater than 20 grams/min, and greater than 25 grams/min.

In general, a method corresponding to the invention includes providing an elongated shaft with a workingend400 comprising anactive electrode425 carried adjacent to awindow415 that opens to an interior channel in the shaft which is connected to a negative pressure source, positioning the active electrode and window in contact with targeted tissue in a fluid-filled space, activating the negative pressure source to thereby suction targeted tissue into the window and delivering RF energy to the active electrode to ablate tissue while translating the working end across the targeted tissue. The method further comprises aspirating tissue debris through theinterior channel420. In a method, the workingend400 is translated to remove a surface portion of the targeted tissue. In a variation of the method, the workingend400 is translated to undercut the targeted tissue to thereby removechips488 of tissue.

Now turning toFIGS. 13A-13C, other distal ceramic tips of cutting assemblies are illustrated that are similar to that ofFIGS. 9-11, except the electrode configurations carried by theceramic members405 are varied. InFIG. 13A, the electrode490A comprises one or more electrode elements extending generally axially distally from thewindow415.FIG. 13B illustrates an electrode490B that comprises a plurality of wire-like elements492 projecting outwardly fromsurface454.FIG. 13C shows electrode490C that comprises a ring-like element that is partly recessed in agroove494 in the ceramic body. All of these variations can produce an RF plasma that is effective for surface ablation of tissue, and are positioned adjacent towindow415 to allow aspiration of tissue detritus from the site.

FIG. 14 illustrates another variation of a distalceramic tip500 of aninner sleeve512 that is similar to that ofFIG. 9 except that thewindow515 has adistal portion518 that extends distally between the cuttingedges520, which is useful for aspirating tissue debris cut by high speed rotation of the cutting edges520. Further, in the variation ofFIG. 14, theelectrode525 encircles adistal portion518 ofwindow515 which may be useful for removing tissue debris that is ablated by the electrode when theceramic tip500 is not rotated but translated over the targeted tissue as described above in relation toFIG. 12B. In another variation, adistal tip500 as shown inFIG. 14 can be energized for RF ablation at the same time that the motor drive rotates back and forth (or oscillates) theceramic member500 in a radial arc ranging from 1° to 180° and more often from 10° to 90°.

FIGS. 15A-15B illustrate other distal

ceramic tips

540 and540′ that are similar to that ofFIG. 14 except the electrode configurations differ. InFIG. 15A, thewindow515 has adistal portion518 that again extends distally between the cuttingedges520, withelectrode530 comprising a plurality of projecting electrode elements that extend partly around thewindow515.FIG. 15B shows aceramic tip540′ withwindow515 having adistal portion518 that again extends distally between the cutting edges520. In this variation, theelectrode545 comprises a single blade element that extends transverse toaxis115 and is in close proximity to thedistal end548 ofwindow515.

FIG. 16 illustrates another variation of distal ceramic tip550 of aninner sleeve552 that is configured without thesharp cutting edges410 of the embodiment ofFIGS. 9-11. In other respects, the arrangement of the window555 and the electrode560 is the same as described previously. Further, the outer periphery of the electrode is similar to the outward surface of the ceramic tip550. In the variation ofFIG. 16, the window555 has at least onesharp edge565 for cutting soft tissue when the assembly is rotated at a suitable speed from 500 to 5,000 RPM. When the ceramic tip member550 is maintained in a stationary position and translated over targeted tissue, the electrode560 can be used to ablate surface layers of tissue as described above.

FIG. 17 depicts another variation of distal ceramic tip580 coupled to aninner sleeve582 that again has sharp burr edges or cuttingedges590 as in the embodiment ofFIGS. 9-11. In this variation, the ceramic monolith has only 4sharp edges590 which has been found to work well for cutting bone at high RPMs, for example from 8,000 RPM to 20,000 RPM. In this variation, the arrangement of window595 and electrode600 is the same as described previously. Again, the outer periphery of electrode595 is similar to the outward surface of the cutting edges590.

FIGS. 18-24 illustrate another electrosurgical RF ablation device or probe700 (FIG. 18) that is adapted for use with ahandpiece702 and motor drive unit105 (seeFIG. 23). InFIG. 23, theconsole704 carriesRF source705A and a negative pressure source oroutflow pump705B which can comprise a peristaltic pump and cassette to provide suction though tubing706 coupled to thehandpiece702 as is known in the art. Theconsole704 further can carry acontroller705C that operates the motor drive as well as actuation and/or modulation of theRF source705A andnegative pressure source705B. A footswitch707ais provided for operation ofRF source705A,negative pressure source705B and optionally the motor drive. In addition, themotor drive105, RF source and negative pressure source can be operated by control buttons707bin the handpiece702 (FIG. 23). In the RF probe ofFIGS. 18 to 22, themotor drive105 does not rotate a cutting blade or electrode but instead moves or reciprocates an RF electrode axially at a selected reciprocation rate (which may be a high or low reciprocation rate or a single reciprocation) to dynamically ablate, resect and remove tissue.

More in particular, referring toFIG. 18, the detachableRF ablation probe700 has a proximal housing portion orhub708 that is coupled to an elongated shaft orextension portion710 that has an outer diameter ranging from about 2 mm to 7 mm, and in one variation is from 5 mm to 6 mm in diameter. Theshaft710 extends aboutlongitudinal axis712 to a working end including a housing orbody715 that comprises a dielectric material such as a ceramic as described above, referred to hereinbelow asceramic housing715. Referring toFIGS. 18, 19A-19B and 20A-20B, it can be seen thatelongated shaft710 comprises anouter sleeve716 and aninner sleeve718. Both

sleeves

716 and718 may comprise a thin wall stainless steel tube or another similar material or composite that is electrically conductive. Theouter sleeve716 has adistal end719 that is coupled to theceramic housing715. Aninterior channel720 extends through thehousing715 to adistal channel opening722 inhousing715. In this variation or embodiment, thechannel opening722 in part faces sideways or laterally in thehousing715 relative toaxis712 and also faces in the distal direction. That is, thedistal opening722 extends over both distal and lateral faces of theceramic housing715.

Referring toFIGS. 19A-19B, a moveableactive electrode725 is configured to extend laterally across awindow726 which has a planar surface and is a section of opening722 inhousing715. As can be seen inFIGS. 20A-20B, theelectrode725 is carried at the distal end of reciprocatinginner sleeve718. Theelectrode725 is adapted to be driven bymotor drive unit105 in handpiece702 (seeFIG. 23) so that proximal-facing edge728aand side-facing edges728bofelectrode725 move axially relative to thewindow726.FIG. 19A and the corresponding sectional view ofFIG. 20A show theinner sleeve718 andelectrode725 moved bymotor drive105 to an extended or distal axial position relative towindow726.FIGS. 19B and 20B show theinner sleeve718 andelectrode725 moved by the motor drive to a non-extended or retracted position relative towindow726. InFIGS. 19A and 20A, thewindow726 has an open window length WL that can be defined as the dimension between theproximal window edge730 and the proximal-facingelectrode edge728. The movingelectrode725 moves through a stroke between a distally extended position (FIGS. 19A and 20A) and a distally retracted position (FIGS. 19B and 20B) wherein the electrode edge728ain the retracted position (FIGS. 19B and 20B) is adapted to extend over theproximal window edge730 to shear tissue and clean the electrode surface. Likewise, referring toFIGS. 19A-19B, the side-facing edges728bofelectrode725 extend over thelateral edges731 ofwindow726 to shear tissue engaged by suction in the window.

As can be seen inFIGS. 20A-20B, theinner sleeve718 comprises a thin-wall tube of stainless steel or another conductive material, and is coupled toRF source705A (FIG. 23) to carry RF current to theelectrode725. Theinner sleeve718 has adistal end732 that coupled by a weld to a conductive metal rod orelement734 that extends transversely through adielectric body735 carried by the inner sleeve. Theconductive element734 is welded toelectrode725 that extends laterally across thewindow726. Thedielectric body735 can be a ceramic, polymer or combination thereof and is in part configured to provide an insulator layer around to electrical conductive components (inner sleeve718 and transverse rod734) to define the “active electrode” as the limited surface area ofelectrode725 which enhances RF energy delivery to the electrode edges728aand728bfor tissue cutting. Theinner sleeve718 also has side-facingwindow736 therein that cooperates or aligns withwindow726 inhousing715 to provide suction through the

windows

736 and726 fromnegative pressure source705B (seeFIGS. 20A and 23) to draw tissue into thewindow726.

Now turning toFIGS. 18, 21A-21B, 22 and 23, the mechanism that axially translates theelectrode725 inwindow726 is described in more detail. As can be understood fromFIGS. 18, 21A and 23, theRF ablation probe700 can be locked intohandpiece702 ofFIG. 22 by inserting tabs737aand737bon flex arms738aand738b(FIGS. 18 and 21A) into receiving openings740aand740bin handpiece702 (FIG. 23). O-rings742aand742bare provided in hub708 (FIG. 21A-21B) to seal thehub708 into the receivingchannel741 in the handpiece702 (FIG. 23).

Referring now toFIGS. 21A-21B, thehub708 is fixed toouter sleeve716 that has a bore orchannel720 therein in which theinner sleeve718 is slidably disposed. Aproximal end744 ofinner sleeve718 has anactuator collar745 of an electrically conductive material attached thereto with a proximal-facingsurface746 that has a bump orcam surface747 thereon. Theactuator collar745 is adapted to reciprocate withinbore748 in thehub708.FIG. 21A shows theactuator collar745 in an extended position which corresponds to the extended electrode position ofFIGS. 19A and 20A.FIG. 21B shows theactuator collar745 in a non-extended or retracted position which corresponds to the retracted electrode position ofFIGS. 19B and 20B.

Theactuator collar745 andhub708 include slot and key features described further below to allow for axial reciprocation of the slidingactuator collar745 andinner sleeve718 while preventing rotation of thecollar745 andsleeve718. Aspring748 between adistal surface750 ofactuator collar745 and a proximally facinginternal surface752 ofhub708 urges the slidingactuator collar745 and the moveableactive electrode725 toward the retracted or proximal-most position as shown inFIGS. 19B, 20B and 21B.

Themotor drive105 of handpiece702 (FIG. 23) couples to arotating drive coupling760 fabricated of a non-conductive material that rotates inhub708 as shown inFIGS. 18 and 21A-21B. Thedrive coupling760 has adistal cam surface762 that engages the proximal-facingcam surface747 on theactuator collar745 so that rotation ofdrive coupling760 will reciprocate the slidingactuator collar745 through a forward and backward stroke AA, as schematically shown inFIGS. 21A-21B. While the cam surfaces762 and747 are illustrated schematically as bumps or cams, one of skill in the art will appreciate that the surfaces can be undulating or “wavy” or alternately comprise multiple facets to provide a ratchet-like mechanism wherein rotation of the rotating drive coupling in 360° will reciprocate the slidingactuator collar745 through a selected length stroke multiple times, for example from 1 to 100 times per rotation of thedrive coupling760. It should also be appreciated that while full and continuous rotation of therotating coupling760 will usually be preferred, it would also be possible to rotationally oscillate (periodically reverse the direction of rotation between clockwise and counter-clockwise) therotating drive coupling760, for example to control a length of travel of the moveableactive electrode725 in thewindow726 where a rotation of less than 360° will result in a shortened length of travel. The stroke of the slidingactuator collar745 andelectrode725 can be between 0.01 mm and 10 mm, and in one variation is between 0.10 mm and 5 mm. The selected RPM of the motor determines the reciprocation rate, and in one variation acontroller705C can select a motor operating RPM to provide a reciprocation rate between 1 Hz and 1,000 Hz, usually between 1 Hz and 500 Hz. In another variation, theRF ablation probe700 can be selectively operated in different reciprocation modes (bycontroller705C) to provide different reciprocation rates to provide different RF effects when treating tissue. In an additional variation, the length of the electrode stroke can be selected for different modes, wherein thehousing708 can be provided with a slidable adjustment (not shown) to adjust the distance between the cam surfaces747 and762 of the slidingcollar745 androtating coupling760, respectively.

The RF probe ofFIGS. 18-22 also can be operated in different RF modes. As described above, a typical RF mode for dynamic RF ablation reciprocates theelectrode725 at a selected high speed while delivering RF current in a cutting waveform to thereby create a plasma that ablates tissue. In another RF mode, thecontroller705C can include an algorithm that stops the reciprocation ofelectrode725 in the extended position ofFIGS. 19A and 20A and then RF RF current in a coagulation waveform can be delivered to theelectrode725. The operator can then move the stationary electrode over a targeted site for coagulation of tissue. In yet another RF mode, thecontroller705C can reciprocate theelectrode725 as at slow rate (e.g., 1 Hz to 500 Hz) while delivering a coagulation waveform to coagulate tissue.

Referring toFIGS. 18, 21A-21B and 24, the rotatingcoupling760 is rotationally maintained inhub708 by aflange770 that projects intoannular groove772 in thehub708. Therotating drive coupling760 is configured for coupling with thedrive shaft775 andtransverse pin776 ofmotor drive unit105 as shown inFIG. 24. As in previous embodiments of cutting or shaver assemblies, thenegative pressure source705B is coupled to apassageway778 in handpiece702 (FIG. 23) that further communicates through the interior of the handpiece withopening780 in the drive coupling760 (seeFIGS. 21A-21B) andlumen782 ininner sleeve718 to suction tissue intowindow726, as can be understood fromFIGS. 19A-21B.

FIG. 22 is a longitudinal sectional view of thedevice hub708 rotated 90° from the sectional views ofFIGS. 21A-21B.FIG. 22 shows the means provided for connecting theRF source705A to theprobe700 and electrodes. InFIG. 23, first and second electrical leads790aand790bare shown schematically extending fromRF source705A throughhandpiece702 to electrical contact surfaces792aand792bin the receivingchannel741 in thehandpiece702.FIG. 22 shows electrical contacts795aand795binhub708 as described previously which engage the contact surfaces792aand792bin the handpiece. InFIG. 22, the first electrical lead790aand contact surface792adelivers RF electrical current to contact795ainhub708 which provides at least one ball andspring contact assembly796 to deliver current to theconductive actuator collar745 andinner sleeve718 which is connected toactive electrode725 as described above. It can be understood that the ball andspring contact assembly796 will allow theactuator collar745 to reciprocate while engaging thecontact assembly796. In one variation, two ball andspring contact assemblies796 are provided on opposing sides of thehub708 for assuring RF current delivery to theactuator collar745. The inward portions of the two ball andspring contact assemblies796 also are disposed in axial channels or slots798aand798bin theactuator collar745 and thus function as a slot and key features to allow theactuator collar745 to reciprocate but not rotate.

Referring again toFIG. 22, the second electrical lead790bconnects to contact surface792binhandpiece receiving channel741 which engages the electrical contact795binhub708 of theRF probe700. It can be seen that anelectrical path802 extends from electrical contact795bin thehub708 toouter sleeve716 wherein and an exposed portion of theouter sleeve716 comprises areturn electrode815 as shown inFIGS. 18, 19A-19B and 24. It should be appreciated that theouter sleeve716 can be covered on the inside and outside with a thin electrically insulating cover or coating (not shown) except for the exposed portion which comprises thereturn electrode815. Theinner sleeve718 has aninsulative exterior layer820 such as a heat shrink polymer shown inFIGS. 19A-19B and 20A-20B. Theinsulative exterior layer820 on theinner sleeve718 is provided to electrically insulate theinner sleeve718 from theouter sleeve716.

In a method of operation, it can be understood that the device can be introduced into a patient's joint that is distended with saline solution together with an endoscope for viewing the working space. Under endoscopic vision, the device working end is oriented to place theelectrode725 against a targeted tissue surface in the patient's joint, and thereafter theRF source705A andnegative pressure source705B can be actuated contemporaneously to thereby suction tissue into thewindow726 at the same time that an RF plasma is formed about thereciprocating electrode725 which then ablates tissue. The ablated tissue debris is suctioned through the

windows

726 and736 intolumen782 ofinner sleeve718 to the fluid outflow pathway in thehandpiece702. Ultimately, the tissue debris is carried though the outflow pump system to the collection reservoir830 (FIG. 23). The device and system can be actuated by the footswitch707aor a button707bin the control panel of thehandpiece702 as described previously.

FIG. 24 shows the RF ablation probe or assembly700 from a different angle where it can be seen that therotating drive coupling760 has a bore822 and at least one slot824 therein to receive thatmotor drive shaft775 andtransverse pin776. In another aspect of the invention, thedrive coupling760 has a smoothexterior surface825 in 360° around the coupling to provide an enclosure that surrounds andenclosed shaft775 andtransverse pin776. Theexterior surface825 and 360° enclosure is configured to prevent a fluid outflow indicated by arrow832 (which carries resected tissue debris) from clogging the system. It can be understood that resected tissue may include elongated, sinewy tissue strips that can wrap around thedrive coupling760 which is spinning at 5,000-15,000 RPM after being suctioned with fluid throughopening780 in thedrive coupling760. Prior art devices typically have a drive shaft and pin arrangement that is exposed which then is susceptible to “catching” tissue debris that may wrap around the coupling and eventually clog the flow pathway. For this reason, the rotatingdrive coupling760 has a continuous, smoothexterior surface825. In an aspect of the present invention, a disposable arthroscopic cutting or ablation device is provided that includes a rotating drive coupling that is adapted to couple to a motor drive shaft in a handpiece, wherein the rotating drive coupling has a continuous 360° enclosing surface that encloses the drive shaft and shaft-engaging features of the drive coupling. In other words, thedrive coupling760 of the invention has motor shaft-engaging features that are within an interior receiving channel of the drive coupling. In another aspect of the invention, referring toFIG. 24, thedrive collar760 of a shaver blade includes enclosing features838aand838bthat are configured to carry magnets840aand840b. Such magnets are adapted to cooperate with at least oneHall sensor845 in thehandpiece702. The at least oneHall sensor845 can be used for multiple purposes, including (i) calculating shaft RPM, (ii) stopping shaft rotation and thuselectrode725 and theinner sleeve window736 in a selected axial position, and (iii) identifying the type of shaver blade out of a catalog of different shaver blades wherein thecontroller704 that operates theRF source705A,negative pressure source705B andmotor controller705C then can select different operating parameters for different shaver blades based on identifying the blade type.

FIGS. 25-28 illustrate another electrosurgical RF ablation assembly orprobe1000 that is adapted for use with the handle orhandpiece702 andmotor drive unit105 ofFIG. 23. In this variation, themotor drive105 again does not rotate a cutting blade but is configured only for moving a hook shape electrode1005 (FIG. 25) between a first non-extended position and a second extended position as can be seen inFIGS. 26A and 26B.

As can be seen inFIG. 25, theRF probe1000 again has a proximal housing or hub1006 that is coupled to an elongated extension portion orshaft1010 with an outer diameter ranging from about 2 mm to 7 mm, and in one variation is 3 mm to 5 mm in diameter. Theshaft1010 extends aboutlongitudinal axis1012 to a workingend1015 that includes a ceramic or other dielectric tip orbody1018 which can be a ceramic or glass material as described above. Referring toFIGS. 25 and 27, it can be understood that theelongated shaft1010 includes athin wall sleeve1020 having an interior channel or lumen121 therein and is fabricated of a conductive material such as stainless steel. An optional insulator layer1022 is disposed around a proximal and medial portion of thesleeve1020. The ceramic tip orbody1018 is coupled to the distal end ofsleeve1020 by adhesives or other suitable means. In a variation, as shown inFIGS. 26A and 26B, theceramic body1018 has adistal surface1024 the defines a distal plane DP that is flat and orthogonal to thesleeve1020, i.e., theaxis1012 of the sleeve is angled at 90° relative to plane DP. In another variation, thedistal surface1024 and distal plane DP can be sloped or inclined at an angle between 45° to 90° relative to theaxis1012. Alternatively, such a distal surface can be curved in a concave or convex shape, or in other cases could have combinations of planar and curved segments.

Referring toFIGS. 26A-26B and 27, themoveable hook electrode1005 extends throughopening1025 in adistal face1026 of thedielectric tip1018. Anelectrode shaft1028 that extends entirely throughsleeve1020 which is connected to proximal drive mechanism1030 (FIG. 25) in the interior of hub1006 for moving theelectrode1005 between the non-extended position ofFIG. 26A and the extended position ofFIG. 26B. In the fully extended position ofelectrode1005 shown isFIG. 26B, the surface of the hook portion of the electrode can extend from 0.05″ to 0.50″ from thedistal surface1024 of thedielectric tip1018. As can be seen inFIGS. 26A-26B, thedielectric tip1018 has arecess1030 in its distal surface and anotch1033 to receive thetransverse portion1035 of theelectrode1005 when in the non-extended position ofFIG. 26A. Thus, in the configuration shown inFIG. 26A, the distalmost surface of the workingend1015 comprises only therounded edge1036 of thedielectric member1018 which is suited for introduction through an access incision or an introducer sleeve into a treatment site.

In this variation, the drive mechanism that moves theelectrode1005 axially can be the same mechanism as described above in the previous embodiment and shown inFIGS. 21A, 21B and 22. That is, themotor drive105 in thehandpiece702 detachably couples to adrive coupling1032 in the hub1006 and the motor's rotation is converted to linear motion as described previously (FIG. 25). InFIGS. 26A, 26B and 27, it can be seen that interior channel or lumen121 insleeve120 is connected to thenegative pressure source705B for aspirating fluid and tissue debris from a treatment site.FIGS. 21A-22 illustrate theproximal end1038 of the elongated member1028 (phantom view) that carrieshook electrode1005 can be coupled to an shortenedinner sleeve718 to allow for fluid outflows indicated at arrows AR through thehub708.

In the variation shown inFIGS. 26A-26B, the controller704 (FIG. 23) includes control algorithms that slow down the motor speed and can be adapted to only move the electrode between the non-extended electrode position (FIG. 26A) and the extended electrode position (FIG. 26B). The controller can use the Hall sensor signals as described above to indicate the rotational position of the drive coupling1032 (FIG. 25), that again carries magnets840aand840bwherein control algorithms can determine or confirm the linear position of theelectrode1005. AHall sensor845 is shown in FIG.23 that is proximate the magnets840aand840b. A joystick or button707bon the handpiece702 (FIG. 23) can be actuated by the physician to move theelectrode1005 between the non-extended and extended electrode positions (FIGS. 26A-26B).

Referring toFIG. 27, it can be seen that theelectrode1005 can comprise a tungsten wire or other similar material, and in one variation, the electrode is a tungsten wire with a diameter of 0.020″, although other diameters are suitable depending on the overall dimensions of the device. As can be seen inFIG. 27, the elongated member orelectrode shaft portion1028 comprises aconductive hypotube1040 with thelongitudinal portion1042 of theelectrode1005 extending into and fixed in the lumen1044 ofhypotube1040, which is one variation can be a 0.032″ OD stainless steel hypotube. Thelongitudinal portion1042 ofelectrode1005 can be fixed to thehypotube1040 by crimping, welding, press fitting or other suitable means.FIG. 27 further shows aninsulator layer1045 around thehypotube1040 which can be a heat-shrink sleeve which is used to electrically insulate the hytotube1040 (which carries RF current to active electrode1005) from theouter sleeve1020 which comprises areturn electrode1050.

In another aspect of the invention, the dielectricdistal tip1018 includes at least one fluid flow passageway therethrough that can comprise theopening1025 indistal face1026 which receives thetranslatable electrode1005. Such a flow passageway communicates with thenegative pressure source705B (i.e., outflow pump) for removing fluid and tissue debris from a treatment site. In the variation ofFIGS. 26A-27, such a flow passageway includes a plurality of channel portions1055a-1055dprojecting radially outwardly from opening1025 through which theelectrode1005 extends.FIGS. 29-30 illustrate otherdielectric tips1018′ and1018″ with other configurations offlow channels1060A and1060B that may be used. The electrode shaft may extend throughopening1025 in the center of thedielectric tip1018 or any off-center position.

Still referring toFIGS. 26A-27, thedistal tip1018 and flow channels1055a-1055dhave certain characteristics and features to perform optimally for removing fluids and tissue debris from a treatment site. In one aspect, the flow channels1055a-1005dare provided with a sufficient cross-section to allow for fluid flows of at least 50 ml/min, and more often at least 100 ml/min or at least 200 ml/min. As a reference, the negative pressure source oroutflow pump705B used in one variation of the invention is capable of fluid outflows of 1,250 ml/min when there are no restrictions to such fluid outflows.

In order to accommodate the fluid outflows described above, the total cross-sectional area of the flow channels1055-1055din the variation shown inFIGS. 26A-27 indicated at CA is least 0.001 square inches and often greater than 0.002 square inches.

In another aspect, referring toFIGS. 27 and 28, thedistal tip1018 is configured with a plurality oflongitudinal elements1065 intermediate the flow channels1055a-1055dthat support the electrode'slongitudinal portion1042. The sectional view ofFIG. 28 shows thedielectric tip1018 without the electrode to better view thelongitudinal elements1065. As shown inFIG. 28, theelements1065 only contact the electrodelongitudinal portion1042 at a single point or over a short longitudinal dimension Z, for example, less than 2 mm or less than 1 mm. In another aspect, the channels1055a-1055dtransition from the first distal cross-sectional area described above tochannels1075 that have a much larger cross-sectional area in the proximal direction as shown inFIGS. 27 and 28. It has been found that tissue debris can get entangled in elongate flow channels, therefore it is useful to provide such flow channels1055a-1055dwith a cross-section that increases tolarger channels1075 in the proximal direction, that is, in the direction of fluid outflow indicated by arrows AR inFIG. 27.

FIG. 28 is a slightly off-center sectional view of thedielectric tip1018 without showing theelectrode1005. It can be seen that the cross-sectional area of the channels1055a-1055dincrease in the proximal direction from channel area CA inopening1025 to channel area CA′ in theproximal portion1077 of thedielectric tip1018, ignoring the area of theelectrode1005 orshaft1028. In the variation shown inFIG. 28, it can be seen that more proximal longitudinal rails or features1080 are dimensioned to support thehypotube1040 that carries theelectrode1005 as described above.

In a method of use, the single-use probe1000 ofFIGS. 25-26B is assembled withhandpiece702 and the default position of theelectrode1005 is the non-extended or retracted position ofFIG. 267A. After assembling thedisposable probe1000 and handpiece, thecontroller704 and control algorithms therein can recognize the type of probe, which can be accomplished with Hall sensors that recognize the strength one ormore magnets1072 inhub708 as shown in the probe variation ofFIG. 22. It can be understood that amagnet1072 inFIG. 22 could be provided with from 2 to 10 different strengths that can be distinguished by a Hall sensor1075 (FIG. 22), then a corresponding 2 to 10 different probe types can be identified. If two magnets are disposed on opposing sides of thehub708 as shown inFIG. 22, each having from 2 to 10 different strengths, then the large number of permutations would allow for identification of a larger number of probe types. It should also be appreciated that the rotating magnets840aand840bin thedrive coupling760 ofFIG. 24 can have different strengths in different probe types and then can be used for acquiring Hall sensor signals for (i) rotating operating parameters as well as being used for (ii) device recognition or probe type identification. Thecontroller704 is configured with a control algorithm to activate and de-activate the motor drive unit to thereby stop movement of the elongate member orshaft1028 andelectrode1005 in both the non-extended position (FIG. 26A) and the extended position (FIG. 26B). In one variation, the control algorithm is further configured to deliver RF current to theelectrode1005 only in the electrode-extended position ofFIG. 26B. The system further is configured to selectively deliver RF current to the electrode in a cutting waveform or a coagulation waveform.

In a method of use, after theprobe1000 has been recognized and identified, the controller optionally can be configured to actuate themotor drive unit105 to then move and stopelectrode1005 in the non-extended position ofFIG. 26A. Thereafter, the physician can introduce the workingend1015 through an incision into a treatment site in a patient's joint. The physician then can use control button707bon thehandpiece702 to actuate themotor drive105 which moves and stops theelectrode1005 in the extended position as shown inFIG. 26B. Thereafter, the physician can engage targeted tissue with thehook electrode1005 and activate RF energy delivery with either an actuator button707bon thehandpiece702 or a foot pedal770a(FIG. 23). Thecontroller704 can be configured to activate thenegative pressure source705B contemporaneous with the activation of RF delivery. Alternatively, thenegative pressure source705B can be operating at a first aspiration level as the physician prepares to use RF, and then a second increase aspiration level when the RF is activated. Then, with the RF activated, the physician can move or translate theelectrode1005 to cut and ablate tissue. When the treatment is completed, the physician then can use an actuator button or joystick to move the electrode to the non-extended position ofFIG. 26A and withdraw theprobe1000 from the treatment site.

The method of usingprobe100 as described above contemplates thatelectrode1000 being static in the extended position shown inFIG. 26B with the physician manually translating thehook electrode1005 against targeted tissue, for example, to cut a ligament. In another method of use, herein called a “dynamic ablation mode”, thecontroller704 can be provided with control algorithms that rotate themotor drive105 to rapidly reciprocate thewire electrode1005 during RF energy delivery to the electrode. It has been found that such a rapid reciprocation of theelectrode1005 over a relatively short stroke can facilitate RF cutting of tissue, which is similar to the RF cutting effect with the probe variations ofFIGS. 18-22 above. In one variation, the stroke ofelectrode1005 in the dynamic ablation mode can range from 0.01 mm and 5 mm, often being in a range between 0.1 mm and 4 mm. The rate of reciprocation can range from 5 Hz to 500 Hz, and often in the range from 10 Hz to 100 Hz.

Although particular embodiments of the present invention have been described above in detail, it will be understood that this description is merely for purposes of illustration and the above description of the invention is not exhaustive. Specific features of the invention are shown in some drawings and not in others, and this is for convenience only and any feature may be combined with another in accordance with the invention. A number of variations and alternatives will be apparent to one having ordinary skills in the art. Such alternatives and variations are intended to be included within the scope of the claims. Particular features that are presented in dependent claims can be combined and fall within the scope of the invention. The invention also encompasses embodiments as if dependent claims were alternatively written in a multiple dependent claim format with reference to other independent claims.

Other variations are within the spirit of the present invention. Thus, while the invention is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.