US20070179525A1 - Multifunctional tool and method for minimally invasive surgery - Google Patents

Abstract

An apparatus and method for minimally invasive surgery. The apparatus can comprise a tool which includes a multi-functioning end effector for insertion into a patient, a user control adapted for use by the surgeon external of the patient, and an intermediate section between the end effector and the user control to translate control instructions from the user control through an actuating mechanism to operate the end effector in one of at least two different functioning states. No instrument exchange is necessary to change between states. The actuation mechanism could be a manually operated mechanical mechanism. Alternatively, it could be partially or fully electromechanical or electrical or electronic. According to one aspect, the end effector is a rigid link mechanism. According to another aspect, the end effector could be a compliant mechanism, at least in part. Another aspect of the invention includes the ability of the end effector to have at least some articulation in addition to grasping and cutting functions.

Description

REFERENCE TO RELATED APPLICATIONS
• This application is a Continuation of Ser. No. 10/213,645 filed Aug. 5, 2002, which is based upon U.S. Provisional Application Ser. No. 60/310,314, filed Aug. 6, 2001, and Ser. No. 60/310,315, filed Aug. 6, 2001, all are incorporated by reference herein.
I. BACKGROUND OF THE INVENTION
• 1. A. Field of the Invention
• This invention relates to Minimally Invasive Surgery tools and methods, and in particular, to multifunction tools and methods.
• 2. B. Problems in the Art
• Recent advances in the medical sciences have lead to the continued acceptance of Minimally Invasive Surgery (“MIS”). Originally envisioned as far back as about 1900, MIS is today being considered as a replacement to traditional “open” surgeries throughout the body including the chest, spine, abdomen, and pelvis. The major difference between MIS and traditional surgery is the surgeon's access to the patient. During MIS, the surgeon makes several small incisions (under one centimeter) in the patient's skin to gain access to the patient's body. Through one of these incisions is placed the endoscope—a narrow cylindrical scope attached to a camera. The remaining ports allow a variety of specially designed surgical instruments to enter the operating area.
• MIS offers many significant advantages to conventional surgery. Traditionally, most postoperative problems have been a result of the large wounds left from open surgery. This leads to long hospital stays, lengthy aberration from normal life, high health care costs, and great personal pain and discomfort. MIS has the potential to reduce recovery time from weeks to days. Furthermore, MIS reduces bowel handling and serosal drying—the two major causes of recovery irritation (Cuschieri, Alfred, 1992. Laparoscopic Biliary Surgery. Oxford: Blackwell Scientific, 1992, pp. 26-98.)
• While MIS offers many potential benefits to the patient, there are a number of obstacles standing in the way of more widespread use. First, the surgeon cannot view the operating area in three dimensions. This is a result of the endoscope's image being displayed on a television monitor. Second, the perception of distances within the body is a function of their orientation with respect to the endoscope. Objects that are closer to the endoscope will appear much larger than objects that are further away (Cuschieri, 1992. Id.). Finally, the surgical instruments themselves continue to be a limiting factor in the advancement of MIS because of limited mobility and lack of multifunctionality. While the first two of these obstacles can be overcome with practice and proficiency on the surgeon's part, the third suggests the need for the development of new and innovative tools for MIS.
• There is a need in the art for more versatile tools for MIS that have the potential to expand the capability of MIS surgical instruments currently commercially available. To meet this goal, a number of current limitations have been identified.
• First, most conventional tools possess only four degrees of freedom. These include translation along the longitudinal axis of the instrument, rotation around the longitudinal axis of the instrument, relative rotation around the entry point of the instrument to the body, and the opening and closing of the gripper's jaws (Melzer, A Q., G. Buess, and A. Cuschieri, 1992. Operative Manual of Endoscopic Surgery. Berlin: Springer Varlag, 1992, pp. 14-36.) Due to the kinetic qualities of the human hand and arm, during open surgery the surgeon can perform movements of approximately twenty degrees of freedom (Melzer, 1996. “Endoscopic Instruments—Conventional and Intelligent.”,Endosurgery, New York: Churchill Livingstone, 1996, pp. 69-95.) Because the conventional surgeon's motion is virtually unimpeded by external constraints, the minimally invasive surgeon looses a significant amount of control due to limited degrees of freedom.
• Second, there is a need for multifunctional MIS tools. Multifunctional tools could provide several advantages over standard single function tools. Studies have shown that 10-30% of total operating time is used for changing between tools with single functions (Metzler 1996, Id.). Multifunctional tools have the potential to reduce tool changeover time by having the ability to perform two or more previously distinct functions in one. Besides increasing operative time, tool changeover can lead to uncontrollable bleeding. During a tool switch the tissue being worked on needs to be subsequently grasped, coagulated and transected before a new tool can be inserted. Bleeding may occur at any point during this process immediately impeding the view of the surgeon (Melzer 1996, Id.). Studies have shown that the primary reason for converting from a minimally invasive technique to open surgery is uncontrollable bleeding (Cuschieri, A., F. Dubois, J. Mouiel, P. Mouret, H. Becker, G, Buess, M. Trede, H. Troild, 1991. “The European Experience with Laparscopic Cholecystectomy.”American Journal of Surgery, Vol. 161, pp. 385-387.) Exchange time, disruption of process flow for the surgical procedure, risk of tissue injury, and other issues regarding tool utilization in MIS are discussed in more detail at Mehta, N., Haluck R., Frecker M., Snyder, A. (2002)Sequence and Task Analysis of Instrument Use in Common Laprascopic Procedures. Surgical Endoscopy, 16, 280-285.
• Third, minimally invasive surgical tools are only mobile around the fixed access point of entry into the operating area. Once an initial insertion is made into a patient, a fixed trocar sleeve is put in place through which tools can then be slid in and out. The trocar sleeve defines a conical section in the operative cavity that will be accessible with the surgical instrument. The limitations of this conical section require significant manual dexterity on the part of the operating surgeon (Cuschieri, 1992, supra).
• Fourth, conventional tools lack the ability to reach behind obstructions. There are a number of instances during surgery that the surgeon needs to access a point behind a vessel or tissue. Presently available tools make this motion impossible and require the surgeon to find a different, less optimal, line of approach.
• There are a number of issues that must be dealt with when developing a new minimally invasive tool. The first of these issues is reposability. A reposable instrument is one that can be re-used. If an instrument is to be reposable then it must have the ability to be completely sterilized. In order to be sterilized, the instrument must have the ability to withstand autoclave temperature of 15 to 120° C. or gas sterilization temperature of 127° F. with 100% humidity (Cappelleri, D., M. Frecker, T. Simpson, and A. Snyder. 1999. “A Metamodel-Based Approach for Optimal Design of a PZT Bimorph Actuator for Minimally Invasive Surgery.” ASME Journal of Mechanical Design, 24, 2, pp. 354-357.) Alternatives to reposable instruments are disposable instruments. Disposable instruments greatly reduce preparation time by eliminating the need for sterilization. However, using disposable instruments is approximately ten times most costly than using reposable instruments. Furthermore, disposable instruments tend to be less precise than reposable ones and raise ecological concerns (Melzer, 1996, Id.).
• Another issue is the ergonomics of the instrument. It has been suggested that an MIS instrument handle has to function independently of the rotation of the instrument tip. Expanding this axiom to a multi-degree of freedom design, preferably all degrees of freedom must function independently of one and other. Additionally, all functions of the instrument preferably must be capable of being carried out with one hand.
• There are a number of present design preferences for a MIS grasping tool including but not limited to opening width of jaws, length of jaws, t response time of jaws, and force required to clamp a suture needle.
• The maximum diameter of the tool is limited by the inner diameter of the trocar sleeve being used in surgery. Presently trocar sleeve inner diameters of twelve, nine, seven, five, and three millimeters are in common use. The trend in MIS is towards instruments of smaller and smaller diameters. This trend places more emphasis on the development of instruments at the smallest end of the available spectrum.
• Therefore, a need in the art has been identified, namely the need for a new tool for MIS that responds to the current limitations and the general requirements of minimally invasive instruments.
• There have been several attempts at creating a multi-degree of freedom gripper prior to this paper. An example of a commercially available multi-degree of freedom gripper is called the Roticulator™ available from USSC, Norwalk, conn., USA. The Roticulator achieves its fifth degree of freedom with the addition of a semi-rigid link between the handle and the jaws of the instrument. As the link is extended beyond the confinement of the handle, the stresses causes by the handle are released allowing the link to return to its naturally curved shape. When the link is fully extended, the gripper is at approximately a 63.5-degree angle with the centerline of the instrument. One issue is the Roticulator's inability to resist a force perpendicular to its jaws when extended. To combat this problem, surgeons have taken to placing a clamp on the instrument such that the tool cannot rotate along the long axis of the instrument. This allows the tool to resist a perpendicular force however it also eliminates a degree of freedom from the instrument. This returns the tool's capabilities to the standard three degrees of freedom.
• Furthermore, as the instrument is rotated around its long axis, the tip sweeps out a circle. This is substantially different from the traditional gripper who exhibits simple rotation about its axis during the same action. As a result, the axial orientation of the tip cannot be changed in the extended position without considerable experience on the part of the surgeon (Melzer, 1996, supra.).
• A. Melzer et. al. has proposed meeting the need for instruments with increased degrees of freedom by introducing a controllable ball-and-socket joint into the shaft of a gripper (Melzer, 1992, supra.). Every movement of the handle at the outer joint would be translated to a similar movement of the inner ball-and-socket. Such an instrument would be based on the mechanical remote-control grasper currently used in advanced industrial applications (Melzer, 1992, Id.). Presently, it is not believed that such a design has advanced beyond the conceptual phase for use in MIS.
• In order to allow a gripper's tip to both pivot and rotate, the axis of pivot preferably should lie along the centerline of the instrument. A need has been identified in the art to achieve this criterion.
II. SUMMARY OF THE INVENTION
• A. Brief Summary of the Invention
• The present invention includes apparatus and methods for MIS. One apparatus comprises a tool which includes a multi-functioning end effector for insertion into a patient, a user control adapted for use by the surgeon externally of the patient, and an intermediate section between the end effector and the user control to translate control instructions from the user control through an actuating mechanism to operate the end effector in one of at least two different functioning states. No instrument exchange is necessary to change between states. The actuation mechanism could be a manually operated mechanical mechanism. Alternatively, it could be partially or fully electromechanical or electrical or electronic. According to one aspect, the end effector is a rigid link mechanism. According to another aspect, the end effector could be a compliant mechanism, at least in part. Another aspect of the invention includes the ability of the end effector to have at least some articulation in addition to other functions.
• In one aspect of an apparatus according to the invention, the end effector includes first and second jaws. The jaws include surfaces that can effectuate grasping or dissecting, or surfaces that can effectuate cutting by scissors action. Compliant or non-compliant structure between the jaws and actuating mechanism facilitates translation of actuation movement to movement of cutting edges or blades on jaws in a scissors action. Another aspect utilizes compliant structure to enable not only movement of jaws relative to one another in a first plane, but conversion between operation of the tool in such a first state, where the jaws move towards and away from each other in response to a first actuation or input force, but also operation in a second mode or state where jaws move towards and away from each other in response to a second actuation or input force. In one aspect, the device automatically switches from state to state dependent on the input force or the selection of actuation. In one aspect, the device automatically switches from state to state dependent on the input force or the selection of actuation.
• In a further aspect of an apparatus according to the invention, each jaw is along a longitudinal axis between a proximal end and a distal end, and has a grasping surface along at least a portion of it. A cutting surface or blade is formed in or positioned on or in the margin of one side of the grasping surface of each jaw. In one embodiment, when the grasping surfaces of the jaws are brought together, the cutting blades are on opposite sides for each jaw, but near or in the same plane as the grasping surface of its jaw. When in the first state, the jaws are aligned with the grasping surface of each jaw facing each other and the jaws are moveable generally in a first plane relative to one another between a closed position, where grasping surfaces of the jaws come in close proximity, or into abutment at least at some points, and an open position where there is separation between grasping surfaces. Actuation pivots the jaws between open and closed positions in the first functional state for the tool. When in the second functional state, the blades of the jaws are aligned and moveable by actuation generally in a second plane relative to one another between a closed position, where cutting blades come into close proximity or overlap one another, and an open position where there is separation between cutting blades. Actuation pivots the cutting blades, generally in the second plane in a scissors action between open and closed positions. Actuation forces can be translated to the blades by compliant or non-compliant mechanism(s), or combinations thereof.
• In one aspect of the invention, at least one jaw has a distal section that is mechanically linked to a proximal section. The distal section can move in the second plane when the tool is in the second functional state (the cutting state), but moves in the first plane in the first functional state (the grasping state).
• In another aspect of the invention, both jaws have distal sections that are mechanically linked to their respective proximal sections. The distal sections can move in the second plane when the tool is in the second functional state, but move in a first plane in the first functional state.
• In a still further aspect of the invention, if both jaws have mechanically linked distal sections, those sections can be articulated in the second plane. The articulation can either be in the same direction; to create articulated grasping jaws to either side of the first plane. When the jaws are moved in the first plane, the articulated distal sections function as articulated grasping or dissecting jaws. If the articulation of the distal sections is in opposite directions and the jaws are in a closed position, the distal sections can be moved relative to one another to create two moving scissors blades.
• In a method according to one aspect of the invention, multiple functions from an end effector can be performed without tool exchange by actuating jaws inside the patient to bring grasping surfaces towards and away from one another in a fist functional state, and actuating the jaws so that at least portions of the jaws having cutting surfaces can be brought towards and away from one another in a second functional state. In a further aspect of a method according to the invention, the movement of the jaws in first and second states could be by mechanical linkage or by compliant mechanism. In another aspect, articulation of a section of the jaws adds another function to the end effector.
• B. Objects, Features, or Advantages of the Invention
• Multi-functionality in minimally invasive surgery tools and methods is expected to benefit both surgeons and patients by decreasing the number of tool exchanges required, shortening operation time, reducing risk of inadvertent tissue trauma during instrument exchanges, and minimizing disruption of the surgeon's train of thought during a procedure. Having a multifunctional instrument may result in improved surgical techniques since the surgeon will be less likely to use a single function tool for purposes other then its intended purpose. The articulating feature will also add to the versatility of the instrument allowing the surgeon to have non-linear access, which is currently unavailable from existing single function tools.
• It is therefore a principle aspect, object, feature, or advantage of the present invention to provide an apparatus and method for MIS, which improves over and/or solves problems and deficiencies in the state of the art.
• Further aspects, objects, features, or advantages of the present invention include an apparatus and method for MIS which:
• (a) is flexible and versatile, including the capability of multifunction and substantial degree of freedom of movement.
• (b) Easily, efficiently, and effectively changes between functions;
• (c) Does not substantially increase size or cost of the apparatus, and may be amenable to miniaturization or automation;
• (d) Reduces time needed for operative procedures;
• (e) Reduces disruption of the process flow of the operation;
• (f) Reduces risk of injury during operations;
• (g) May be implemented in resposibles and disposibles;
• (h) Retains most or all needed functional requirements of MIS;
• (i) Is durable;
• (j) Is economical;
• (k) Increases the effectiveness of the surgeon and the surgery.
• These and other aspects, objects, features, or advantages of the invention will become more apparent with reference to the accompanying specification and claims.
III. BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is an elevational view of a MIS tool with a multi-functional end effector according to one embodiment of the invention.
• FIG. 2 is an enlarged perspective view of an end effector according to an embodiment of the present invention that could be used with the tool ofFIG. 1 showing, for generally a side view, the end effector in a first or grasping state (jaws open).
• FIG. 3 an enlarged view of the end effector ofFIG. 2 but in top plan view and in a second or scissors state (jaws open).
• FIG. 4A is an enlarged view of an embodiment of an actuating handle that could be used with the tool ofFIG. 1, with portions exposed to show the inner working components of the handle.
• FIG. 4B is an enlarged sectional view taken from the perspective ofline4B-4B ofFIG. 4A.
• FIGS.5 and 6 show diagrammatically how selection between multiple functions for the end-effector is accomplished at the handle ofFIG. 4A.
• FIG. 7 is an enlarged perspective view of an end effector for an alternative embodiment according to the present invention.FIG. 7 shows a compliant mechanism end effector with its jaws in a normal, neutral or unactuated state, where the jaws have grasping surfaces which are separated less than a maximum amount.
• FIG. 8 is an enlarged end view of the end effector ofFIG. 7.
• FIG. 9 is similar toFIG. 7 but shows the grasping jaws actuated to an open position greater than the neutral position ofFIG. 7.
• FIG. 10 is similar toFIG. 9, but showing the end effector in a grasping state with the jaws in a closed position.
• FIG. 11 is similar toFIGS. 7, but shows the end effector in a second, different function state, a scissors state with the distal end of the end effector in an open scissors position.
• FIG. 12 is a set of diagrams relating to design of the compliant end effector ofFIGS. 7-11 by topology optimization.
• FIG. 13 is a perspective diagram of the initial solid model based on the solution ofFIG. 12.
• FIG. 14 is a simplified perspective view of a handle design for the compliant end effector ofFIG. 7, showing in a cut-away or exposed fashion the inner-actuating components.
• FIG. 15 is a diagrammatic illustration of a system for a semi-robotic use of the compliant end effector such as that shown inFIG. 7 and an electroactive actuator.
• FIGS. 16A and 16B are graphs showing experimental data of a simulated operation of the compliant end effector ofFIG. 7.
• FIG. 17A is an isolated perspective view of a third embodiment according to the present invention, showing a multi-functional end effector comprising grasping and cutting jaws, shown in a grasping state (closed position). The jaws are also articulatible.
• FIG. 17B is similar toFIG. 17A but shows the end effector in a grasping state (open position).
• FIG. 17C shows the end effectorFIG. 17A converted to a scissors state or mode with the scissoring sections of the jaws in an open position.
• FIG. 17D shows the end effector ofFIG. 17A in a third functional position, where distal sections of the jaws are articulated to the side of the centerline of the end effector and the jaws are open in a grasping mode such that the articulated distal sections of the jaws can function as articulated grasping jaws.
• FIG. 17E is similar toFIG. 17D but shows the jaws in a closed articulated grasping position.
• FIGS.18A-B are simplified diagrams illustrating how the end effector ofFIG. 17A-E can function as straight grasping jaws, as scissors, or as articulated grasping jaws.
• FIG. 18C is a further illustration of articulation.
• FIG. 19A is a more detailed, enlarged, isolated view of an end effector of the style of the embodiment ofFIG. 17A-E, further showing structure for allowing mechanical linkage mechanism grasping actuation of the end effector jaws, illustrating the jaws in a grasping state, closed position.
• FIG. 19B is similar toFIG. 19A, but shows actuation of the jaws to an open grasping position.
• FIG. 19C is similar toFIG. 19B showing actuation of the jaws to an open grasping position with the distal sections of the jaws articulated to the left of the centerline of the end effector.
• FIGS.20A-C are simplified diagrams illustrating how side to side articulation of distal sections of jaws through a cabling arrangement can be produced.
• FIG. 20D is a top plan view of the end effector of FIGS.17A-D illustrating how cabling or wires to the articulatable distal sections of each jaw would be connected.
• FIG. 20E is similar toFIG. 20D, but shows an alternative cabling connection.
• FIG. 21A is an isolated simplified perspective view of handle for the embodiment ofFIG. 17A-E, with an exposed view of the interior working components of the handle.
• FIG. 21B is an exploded perspective view of some of the interior working components of the handle ofFIG. 21A.
• FIG. 21C is an enlarged simplified diagrammatic illustration of some assembled interior working components of the handle ofFIG. 21A, and the relationship of such components to other interior working components ofFIGS. 21A and B.
• FIGS.22A-E are diagrammatic illustrations of the parts of the inside of the handle ofFIG. 21A, illustrating the different configurable modes selectable by the surgeon for different functional modes or states of the end effector of FIGS.17A-E.
IV. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION
• A. Overview
• To provide additional understanding of the invention, exemplary embodiments according to the invention will now be described in detail. Some of the exemplary embodiments and the principles related to these embodiments are illustrated in the appended drawings. Frequent reference will be made to the drawings in this detailed description. The same reference numbers will be used to indicate the same or similar parts or locations throughout the drawings unless otherwise indicated.
• It is to be understood that these exemplary embodiments are provided for illustration of some of the forms the invention can take, and not by way of limitation.
• B. General Apparatus Features and Methods
• The general context of the exemplary embodiments will be made with reference to MIS surgery, such as laparoscopy. Most of the embodiments will have at least a multi-function end effector that can grasp or cut by scissors action. These are exemplary of functions of the tool. These functions, as well as additional functions or variations of the functions obvious to those skilled in the art, will be included within the scope of the invention.
• Additionally, certain basic design choices are preferred for the exemplary embodiments, but are not limiting to the general invention. For example, for these exemplary embodiments, an outer diameter of five millimeters is chosen such that the tool can fit through a five-millimeter trocar sleeve. Other outer diameters, many bigger than this, are currently in use in the state of the art. This choice was made in response to the trend towards smaller minimally invasive tools. The articulating tip has been chosen to reach a maximum angle of at least sixty degrees. At the fully rotated positions, the tip preferably can be at least five millimeters from the centerline of the tool. The tool preferably meets the general requirement of a total length of between one and half and three centimeters in total length. It preferably grasps a 0.5 mm suture needle or tissue, opens at least 8-15 mm and closes completely. It is preferably between 1 and 3 cm in length, opens or closes in under two hundred ms, and imposes a force sufficient to grasp tissue or a needle. As can be appreciated, these design choices for the exemplary embodiments are not limiting to the invention, and can vary according to design needs and choices.
• C. Exemplary Embodiment One (Non-compliant multi-function cutting and grasping)
• 1. Structure
• By referring toFIGS. 1-3, a first exemplary embodiment designed for use as a minimally invasive surgical instrument is shown and will be referred to as mechanism ortool10. As generally illustrated inFIG. 1,mechanism10 consists of ahandle12 with mechanical controls, connected to a 32.5 cmlong shaft14 withproximal end16 anddistal end18, and 5 mm diameter end-effector20 (shown in open state) at the end of adistal shaft18. In this embodiment, a surgeon inserts one or more fingers in fixedgrip22, and thumb of the same hand in pivotinggrip24. Relative movement betweengrips22 and24 (here by rotation ofmoveable handle24 in either direction indicated by arrow25) by manual hand movement of the surgeon causes movement of the jaws ofend effector20. These general features are similar to existing MIS tools.
• As is also conventional,tool10 includes a control wheel (rotation knob)28, also manually manipulatable (rotatable in either direction indicated by arrow29) by the surgeon with the same hand (e.g. index finger), which in turn causes like rotation ofshaft14 and/or other connecting structure. This allows 360 degrees rotation of the orientation of the jaws ofend effector20.
• However,tool10 is multi-functional in the sense that, depending on the surgeon's positioning of manuallyselectable switch26, the jaws ofend effector20 either grasp (or dissect) or cut (by scissors action). The selection, or change in selection, between those two functions or states, can be done quickly and easily by the surgeon, on the fly, and with the same hand as is used to move the jaws ofend effector20.
• 2. End-Effector
• FIGS. 2 and 3 illustrate anend effector20 in accordance with an aspect of the present invention, and illustrate how grasping and scissors functions can be effectuated from thesame end effector20.First jaw30 is elongated between aproximal end32 and adistal end34, and has a grasping surface36 (which could have portions serrated), anopposite side38 from the grasping surface, andopposite side walls40 and42 between graspingsurface36 andside38.Jaw30 is pivotable aboutpivot axis52 defined bypivot pin46, which is insertable and held in place as shown indistal end18 ofshaft14.Pivot axis52 crosses at or close to, and is orthogonal with, central orlongitudinal axis50.
• Proximal end32 ofjaw30, on the opposite side ofpivot axis52 from graspingsurface36 ofjaw30, is a pin-in-slot joint connected by apin48 to thedistal end58 of a tube or sub-shaft56 extending from aproximal end57 inhandle12 through the interior ofshaft14. Movement ofsub-shaft56 alonglongitudinal axis50 ofshaft14 causesproximal end32 ofjaw30 to displace fromaxis50, but also change relative fore or aft position alongaxis50, which in turn causesjaw30 to pivot aboutaxis52 aligned withaxis50, and thus move between a closed position, such as shown inFIG. 3 (near and in alignment with axis50), and an open position shown inFIG. 2, extending at an angle from axis50 (seearrow100 ofFIG. 2). Movement ofjaw30 from closed towards open position is effectuated by movingsub-shaft56 in a proximal to distal direction. Movement ofsub-shaft56 in an opposite direction movesjaw30 from open towards closed.
• Second jaw60 has two pieces or sections. A fixedsection62 has aproximal end64 fixed to the end of shaft14 (e.g. welded, pinned, set screw, etc.) and adistal end66 that extends parallel toaxis50. Amoveable section68 is pivotally connected bypivot pin70 to fixedsection62 and can pivot aboutaxis54.Pivot axis54 crosses at or near, and is generally orthogonal to,axis50, but is also generally orthogonal toaxis52.
• Moveable section68 has aproximal end72 that is pivotally connected bypin74 to linkarm76, which is itself pivotally connected bypin78 to the distal end84 of a second tube or sub-shaft80 extending from its proximal end82 inhandle12 through the interior ofshaft14.Pin74 is on an opposite side ofpivot axis54 fromdistal end73 ofsection68, and is also to one side of the longitudinal axis ofsection68. As can be appreciated, longitudinal movement ofsub-shaft80 causesmoveable section68 ofjaw60 to move between a position generally aligned with axis50 (seeFIG. 2) to a position pivoted angularly to axis50 (seeFIG. 3). Ifsection68 is in the position ofFIG. 2, movement ofsub-shaft80 in a proximal-to-distal direction inshaft14 causes linkarm76 to pushproximal end72 ofsection68 out to the side of axis50 (seeFIG. 3), which causesdistal end73 ofsection68 to swing away fromaxis50 in an opposite direction (seeFIG. 3).Section68 can be moved back to alignment overjaw30 by reverse movement ofsub-shaft80.
• As can be seen,sections62 and68 ofjaw60, when aligned, approximate the length and shape ofjaw30, and have grasping surfaces that align with similar surfaces onjaw30. But further,jaw30 has a sharp edge orblade90 along a portion of a side margin of its graspingsurface36.Blade90 is in alignment with a sharp edge or blade92 (whenjaws30 and60 are brought together) on an opposite side margin of the grasping surface ofjaw60; in particular, along a side margin ofmoveable section68 ofjaw60. Thus, by appropriate design,blades90 and92 can pass one another in very close proximity, or even in frictional abutment, to provide cutting by scissors or shearing action, by closingjaws30 and60 (by pullingsub-shaft56 proximally) and reciprocatingsub-shaft80.
• Components forend effector20 are preferably surgical quality metal (e.g. stainless steel, titanium, etc.). Wire electrical discharge machine (EDM) or metal injection molding processes are attractive fabrication methods, because of the small feature sizes involved. Some exemplary dimensions and specifications for one example oftool10 are as follows:

  	Component	Length
  	Jaws (Total length, non-articulated)	15 mm
  	Jaws opening distance at distal ends for	15 mm
  	grasping
  	Scissors blade length	7 mm
  	Scissors opening distance atdistal ends	10 mm

• 3. Handle
• End effector20 could be actuated through traditional mechanical means such as tendon wires or push rods, which could be used with linkages similar to those in existing MIS tools. Many current tools have the surgeon manually open or close a handle that applies tension to a tendon wire. The wire then actuates a slider/crank mechanism that opens or closes the jaws. A tension spring could render the jaws normally closed or normally open. Other actuation mechanisms are possible.
• Therefore, there are many available choices as to ways to create and translate or transfer movement or force generated at a position away from the end effector, out to the end effector. In the case oftool10 ofFIGS. 1-3, linear push-pull force is used to actuate theend effector20; in particular, linear push pull force to movejaw30 in a first plane, and linear push-pull force to movetip68 ofjaw60 in a second plane.
• Alternatively to mechanical actuation, electrical actuation could be used by replacing the tendon wire with, e.g., a piezoceramic actuator, shape memory alloy actuator, or electroactive polymer embedded in or connected to the tool's end effector. A handle similar to those on contemporary MIS tools would then control the amount of voltage applied to the actuation device, which would in turn control the position of the tool's jaws. The latter type of actuation system would also allow for amplified force feedback with the incorporation of a force sensor.
• Other types of actuators possible include, but are not limited to, pneumatic, hydraulic, electroactive or combinations of the same, or combined with mechanical and/or electrical components. Therefore, the precise type of actuation can be selected according to design choice or need. One specific example of a mechanical actuator mechanism is shown inFIGS. 1-4, and is now described in more detail.
• Referring toFIGS. 1-4, and assuming, in a first case, thatjaw60 is in the longitudinally aligned position ofFIG. 2 and thatswitch26 is set for clamping action, rotatinghandle24 toward fixedhandle22closes jaws30 and60 of end effector20 (generally in the direction shown byarrow100 inFIG. 2, in a plane defined byaxes50 and54). Rotatinghandle24 away fromhandle22opens jaws30 and60 (in that same plane of arrow100). The shaft rotation wheel28 (FIG. 1) is used to change the rotational position of the end-effector about itsaxis50. Thus, in this case (the “clamping” state or mode of tool10), the surgeon setstool10 for clamping withthumb switch26, and can open andclose jaws30/60 for clamping action by changing the relationship ofhandles22 and24 to each other.Jaw60 is essentially fixed andjaw30 moves towards and away from it to clamp or dissect. Of course, handle12 can be moved in three spaces, to the extent possible given the constraints of MIS, to positionend effector20 inside the patient.
• In a second case, assumingjaw30 is in a closed position (FIG. 3) andswitch26 is set for scissors action, rotatinghandle24 away fromhandle22 would causemoveable section68 ofjaw60 to rotate out fromaxis50 towards the position inFIG. 3 (generally in the direction shown byarrow102 inFIG. 3, in a plane defined by axes50and52). Rotatinghandle24 towardhandle22 brings moveable section back to jaw30 (in that same plane of arrow100). Thus, in this case (the scissors state or mode of tool10), the surgeon setstool10 for clamping withfinger switch26, and can open andclose jaws30/60 for clamping action by changing the relationship ofhandles22 and24 to each other. Herejaw30 is essentially fixed in place, andjaw60 moved towards and away from it (although in a different plane than when in clamping mode), to give scissors or shearing action.
• As previously explained, multi-function is controlled by which sub-shaft56 or80 is movedrelative end effector20. Ifsub-shaft56 is moved,jaw30 pivots and endeffector20 can be used in grasping mode. Ifsub-shaft80 is moved,moveable section68 ofjaw60 pivots, enabling a cutting mode by scissors action. There are a wide variety of ways selective linear actuation of one of two sub-shafts can be accomplished. In this embodiment, rotational movement ofmoveable handle24 is translated to linear movement to actuate one or the other ofsub-shafts56 or80. One example is described with respect to FIGS.4A-C, which are highly diagrammatical illustrations of the structure and its operation, as opposed to precise, scaled mechanical views.
• Each sub-shaft56 and80 is a half circular push rod (half-moon shaped in cross-section and oriented throughshaft14 as shown inFIG. 4B). Their proximal ends57 and82 are fixed to collars which connect with U shapedbrackets94 and96 respectively. A set screw, eccentric clamp, or other releasable connector fixes proximal ends57 and82 to its respective collar andbracket94 or96, which are slideable withinhandle12, for example along a track or other retaining structure (shown diagrammatically at ref. no.98). Thus, ifbracket94 is slid alongtrack98, only sub-shaft80 will move linearly. Conversely, ifbracket96 is slid ontrack98, only sub-shaft56 will move.
• Thetoggle switch26 on top ofhandle12 controls whether the tool is in cutting or grasping, i.e. selects between translating rotational movement ofhandle24 tobracket96 or94.Mechanical links104 and105 extend frombrackets94 and96 rearwardly inhandle12 throughchannels114A and B respectively intoggle switch26, and terminate in free ends that include a transverse pin extending through and outwardly on opposite sides of each free end oflinks104 and105 (see pin ends106 and107 for the free end oflink14, and pin ends108 and109 for the free end of link105). A through-hole110 in the end ofhandle24 on the opposite side ofhandle pivot112 aligns along anaxis119 whenhandle14 is brought to a reference position (e.g. end of travel away from handle22).Holes113A and B, in the interior sides of opposite side walls13A and B ofhandle12, also are alongaxis119.
• Switch26 is slideable laterally relative to the top ofhandle12 between two opposite extremes (here called “right” and “left” relative to the top views ofFIGS. 5 and 6). Slidingswitch26 to the right (as shown atarrow115 inFIG. 5), shifts bothlinks104 and105 to the right. In turn, pin107 oflink104 enters bore110 ofhandle24 and pin108 oflink105 entershole113A of wall13. Mechanical connection is accomplished betweenhandle24 andbracket94, whilehandle24 is disengaged from connection to bracket96 (and, in fact,bracket96 is locked against movement bylink105 being held fixed to wall113 by pin108). Rotational movement ofhandle24 would be translated into linear movement (seearrow116 ofFIG. 5) byhandle24's pivotal connection to link104 by pin107, which would slide bracket94 (seearrow117 inFIG. 5) and thus linearly move half shaft80 (seearrow118 inFIG. 5) to operate cutting action fortool10.
• On the other hand, clamping mode is shown inFIG. 6. Slidingswitch26 to the left (arrow115 inFIG. 6) causeslinks104 and105 to follow to the left and move pin109 oflink105 intohole110 inhandle24, and pin106 oflink104 intohole113B inopposite handle wall13B. This locks link105 to move with movement ofhandle14, and locks outlink104 from movement. Movement ofhandle24 would be translated to linear movement of link105 (arrow116,FIG. 6), which causes linear sliding of bracket96 (arrow117,FIG. 6), which causes linear movement of half-shaft56 (arrow118 ofFIG. 6), which effectuates clamping action ofend effector20. Essentially, one of the U-brackets is locked into place while the other is free to move and is actuated by rotating the movinghandle24. When thetoggle26 is switched, the other set of linkages is locked and the second set is connected to the moving handle. Thus,tool10 is given multi-function by simple toggle switching between modes or states athandle12.
• The components ofhandle12 can be fabricated using standard and CNC milling machines, such as are well known, or by other methods.
• 4. Lumen orShaft14
• In this embodiment, bothshaft14 and end effector20 (whenjaws30 and60 are closed and aligned along axis50) are designed to fit in a 5 mm port. But, of course, it can be designed for other sizes of trocars (e.g. 3-12 mm) likewise. Still further sizes are possible.
• Sub-shafts56 and80 could be adjacent or in abutment throughshaft14. Alternatively, they could be concentric (one or both being tubular). Other configurations are possible.
• 5. Method of Use
• FIGS. 2 and 3 display end-effector20 ofinstrument10 in its various opened positions. The jaw length, opening dimensions, handle control style and location were determined through collaboration with a practicing surgeon.FIGS. 2 and 3 also display the mating surface finishes of the jaws. A textured surface is desirable for grasping; but a smooth, sharp edged surface is needed for cutting. For this reason the front 7 mm section of the jaws are smooth while the rear portion is textured. A small amount of texture was also added at the very distal ends of the jaws to allow for improved grasping ability at the tip.
• In one embodiment of the tool ofFIGS. 1-3, the following performance features were realized:

  	Function	Force
  	Grasping force	1.34 lb.
  	Maximum Handle force	9.0 lb.
  	Pull-Off Force	2.5 lb. (using red rubber tubing)
  	Cutting Force	2.0 lb.

• D. Exemplary Embodiment Two (Compliant multi-function cutting and grasping)
• 1. Structure
• A “mechanism” has been defined as a mechanical device used to transfer or transform motion, force, or energy. A “compliant” mechanism also transfers or transforms motion, force, or energy, but, unlike rigid-link mechanisms, compliant mechanisms gain at least some of their mobility from the deflection of flexible members rather than from movable joints only. Compliant mechanisms are single piece flexible structures that utilize elastic deformation to achieve motion transmission. The rigid-linked mechanism oftool10 ofFIGS. 1-3 could alternatively by implemented in a compliant mechanism. There are a vast number of ways theend effector20 could be implemented in a compliant mechanism. A variety of methods of design and manufacture of compliant mechanisms are known. Commercially available software exists to assist in design of passive structures. Software has been developed at for the design of compliant mechanisms. A discussion of the same can be found at Dziedzic, R., Frecker, M., Haluck, R. 2002. Design of Multifunctional Compliant Mechanisms for Minimally Invasive Surgery. Minimally Invasive Therapy and Allied Technologies, incorporated by reference herein.
• FIGS. 7-16 illustrate an alternative exemplary embodiment of the invention utilizing a compliant mechanism end effector for multi-function clamping or scissors cutting. This second embodiment, referred to herein as tool10B, includes generally a handle12 (e.g.FIG. 14) with actuating mechanism, anend effector20 withjaws30 and60, and ashaft14 connectinghandle12 withend effector20.
• The general principles of tool10B are similar totool10 ofFIGS. 1-3. A user can select between states or modes (clamp or scissors) by finger-operatedswitch26 extending out of the housing forhandle12. If clamp mode is selected, rotation ofhandle24 towards or away fromhandle22 moves facing clamping surfaces ofjaws30 and60 towards or away from each other. If scissors mode is selected, rotation ofhandle24 towards or away fromhandle22moves blades90 and92 in the sides ofjaws30 and60 towards or away from each other. A rotation control orwheel28, fixed toshaft14, allows the surgeon to rotate the end effector aboutaxis50 of tool10B. Differences fromtool10 ofFIGS. 1-4 include the following.
• 2. End-Effector
• End effector20 of tool10B is a compliant mechanism. It includes what will be called acompliant web120 of flexible members between anattachment end122 adapted for attachment toshaft14, and adistal end124 which forms an integral junction withjaws30 and60.
• One difference fromtool10 is that thecompliant end effector20 of tool10B has what is called a “neutral” position (FIG. 7) for clamping mode, which exists when no forces are applied toproximal end122. As shown inFIG. 7, the neutral position comprisesjaws30 and60 spread apart less than (e.g. approximately ½) their maximum distance. The spread is in the plane ofaxes50and54.
• Web120 here is comprised of multipleflexible members130A-D betweenproximal end122 anddistal end124. The material could be titanium or other surgical grade metal.
• In this version, clamping and scissors modes of tool10B could be produced as follows:
• (a) for clamping action:
• • 1) A sub-shaft throughshaft14 which is connected to the proximal end ofend effector20B, can be actuated to apply a predetermined amount of linear pushing force against a point on portion132 (seeFIG. 8) ofproximal end122 ofend effector20B. The portion of20B including point132, which is substantially concentric to the portion134 (FIG. 8), can move relative toportion134. As a result of such force and movement, the flexible members130, in combination with a c-shapedmember138, move in such a manner to spreadjaws30 and60 atdistal end124 ofend effector20B farther apart (seeFIG. 9) than in the neutral position (FIG. 7), but in the plane ofaxes50/54.
  • 2) A predetermined amount of linear pulling force atpoint132 ofproximal end122 would cause flexible members130 to closejaws30 and60 inplane50/54 (seeFIG. 10).
  • 3) Subsequent opening and closing ofjaws30 and60 could be effected by repeated those steps.
• (b) for scissors action:
• • 1) First,portion132 is pulled to bring the jaws together as inFIG. 10.
• While holding that position, a sub-shaft throughshaft14 applies predetermined linear pushing force against a point onportion134 ofproximal end122 ofend effector20B. As a result of such force and movement, flexible members130 and C-member138 move in a manner which reconfigurejaws30/60 into a scissors mode. The scissors neutral position is closed. Instead of further wideningjaws30/60 in the50/54 plane, such force at that different position would movejaws30/60 from the closed position ofFIG. 10, to a spread position but in the plane ofaxes50/52 (seeFIG. 11), whereblades90 and92 formed in opposite side margins of the grasping surfaces ofjaws30 and60 would be substantially in the same plane.
• • 2) Application of a predetermined linear pulling force against a point onportion134 ofproximal end122, would then cause convergence ofblades90 and92 in or nearplane50/52, such thatblades90 and92 could converge and slightly overlap for cutting action.
  • 3) Release of pulling force would allowjaws30 and60 to return to the position ofFIG. 11, ready for another cutting stroke or strokes, if desired.
• Conversion back to clamping mode could be accomplished by:
• • 1) Applying a predetermined force to point132 ofproximal end122, which would movejaws30 and60 theplane50/54.
• In this example of tool10B ofFIGS. 7-11, the following dimensions exist:

  	Component	Length
  	Jaws (Total length)	36 mm
  	Jaws opening distance at distal ends for grasping	12 mm
  	Scissors blade length	12.5 mm
  	Scissors opening distance at distal ends in	7 mm
  	maximum open position

• Thus,web120 andend effector20 could essentially be manufactured from one integral piece of material, and utilize the design and compliant features to perform the multiple functions performed by the fixed link mechanism oftool10.
• 3. Handle
• As indicated by the functional description ofcompliant end effector20B, above, certain linear forces can be translated to the end effector to actuate the end effector in at least two different functional modes or states. A variety of methods could be used to translate linear forces, including linear forces of varying magnitude and direction, to the end effector. One example is shown and described with respect toFIGS. 1-4. Two sub-shafts56 and80 provide push and pull linear force to two different points or locations at the end effector. The actuating force fromhandle12 ofFIG. 4 could be used to change direction between push and pull for either sub-shaft, but further, manual actuation throughhandle24 can provide variable force to either sub-shaft by the amount of rotational force imparted to handle24 by the amount of squeezing pressure or separation force exerted by the hand of the surgeon relative tohandles22 and24.
• Another example of an actuation mechanism to supply linear force to the end effector is shown in simplified form atFIG. 14.FIG. 14 illustrates handle12 with the interior exposed.Handle12 for tool10B could be similar to handle12 described with respect totool10. It could deliver linear movement via sub-shafts inshaft14 which could be used to operatecompliant end effector20 of tool10B.
• Atoggle switch26, like described with respect totool10, could determine alignment of the rotational output of handle24 (could be from agear arrangement151,152 betweenpoints150 and link142) with respect to one of two linear movement transmission paths throughdouble slider148. A first transmission path would translate rotational movement ofhandle24 viagears151,152, to link144, which would push the top end ofslider148 fore and aft, depending on direction of movement ofhandle14. The bottom ofslider148 would be connected to a push rod that sends one source of linear movement to the compliant mechanism. A similar transmission path comprises of asecond link144 andsecond slider148 could be connected to a second push rod to a second source of linear movement to the compliant mechanism. The precise arrangement and components to accomplish can vary according to design choice.
• According to another aspect of the invention, what is called a static balance mechanism could optionally be included with the actuation system. In the case of a compliant end effector made out of titanium, for example, the compliant design will translate external forces into bending movement determined by the configuration of the flexible members in the compliant mechanism to generate the clamping or scissors actions. Application of a force to overcome the inherent stiffness in the compliant mechanism itself is required, before additional force to generate force at the grasping or scissors jaws. A static balance mechanism equalizing the potential energy due to the inherent stiffness of the end effector, so that the surgeon does not feel or have to overcome the inherent stiffness of material when operating the tool. Springs158 (and another spring on the other side) shown inFIG. 14 are part of one type of static balance mechanism. By selection of their spring constant, position, and the link lengths and orientations of the transmission path of forces between handle24 (the input) and the linear output ofhandle12, static balance can be achieved.
• In the above-described manner, manually actuatable linear forces could be transmitted throughshaft14 to endeffector20 to power the clamping/dissecting or scissors actions ofjaws30 and60. The conversion between clamp and scissors in accomplished by actuating thetoggle switch26 Thus,FIGS. 7-14 illustrate another exemplary embodiment of a multi-function MIS tool. Static balance could also be added, as described.
• a) Piezoelectric Inchworm Actuator for the Compliant Embodiment
• The compliant embodiment of the present invention can be actuated by means other than a manual actuator as discussed above. A piezoelectric inchworm may be used as an alternative means of actuation for the compliant grasper-scissors. One possible example is a commercially available inchworm actuator from Burleigh, for example. (See, e.g., http:H/www.exfo.com/en/products/gf_Family104.asp., Inchworm 800 series).
• The compliant tool10B requires a high actuation force. For instance, the gripper manufactured from titanium requires an actuation force of 10N over a stroke of approximately 0.31 mm to completely close the jaws. In addition, the means of actuation must be small enough to be inserted in tubes currently used in minimally invasive surgery (current tubes often have a diameter of 8 mm). These restrictions make piezoelectric inchworms a candidate for use in actuation of the compliant tool.
• The piezoelectric inchworm actuator can be controlled by acomputerized control system220.FIG. 15 shows a schematic of the entire control system for the compliant gripper The position of the instrumented forceps (jaws30/60), X_h, and the force measured at the end-effector (20), F_g, are sensed and used to control both theinchworm actuator200, V_ic, and the force generation mechanism (not shown) in theuser input handle12, F_r. The end-affector20 anduser input device12 are instrumented with LVDT displacement sensors to measure their position. Through active computer control, the motion of thegripper20 is precisely scaled-down from the input motion provided by the pair of instrumentedforceps30/60. Local force measurements are obtained through the use of a single piezoelectric element present in the actuator, which is wired separately from the rest of the piezoelectric stacks. In this way, the element may be used continuously as a force transducer. The resulting signal must be filtered to remove unwanted high frequency content and scaled so that the reflected force falls within the range of forces sensible to a human operator.
• 4. Shaft/Lumen114
• Like with the embodiment ofFIGS. 1-3,shaft14 could utilize sub-shaft(s) slideable in a bore throughshaft14. If more than one sub-shaft, they could be side-by-side, or concentric (tubular). Tendons with or without sliders could also be used.
• 5. Method of Design
• There are a variety of ways the structure of a compliant end effector could be designed and implemented. The basic functions of a grasping/cutting end effector have been shown and described herein. And, as described above, one way to implement a compliant mechanism is to build structure that effects grasping (jaws converge in a first plane) if pushed with a linear force at one location and effects scissors cutting (blades on sides of jaws and jaws converge in a second plane) if pushed at a different location (or pulled from the same location). Such a structure could be designed through trial and error or empirical methods.
• Optimization of such structure could be accomplished through a variety of methods or through using any of a variety of design tools, including software programming that allows the functions to be entered, along with other basic design constraints or parameters, and the program would design an optimized configuration. One such method is discussed below.
• a) Optimization Routine Used to Design Compliant Tools
• The optimization routine is based on a topology design method for compliant mechanisms with multiple input and output requirements. Topology design refers to the design of the connectivity of the elements in the mechanism. To design a compliant mechanism that will produce a specific output displacement with a certain input force, a mechanism having minimal stiffness (i.e. maximum compliance) in the direction of the desired output is optimal. Simply using optimization to design for a structure with minimal stiffness will result in a solution that has members of zero or minimal area, i.e., the least stiff structure is one with minimum volume. This degenerate solution results from neglecting the requirement that the mechanism must have sufficient stiffness to supply the force at the output point, as well as not fracture or buckle as the motion is executed. Thus, the desired solution may be thought of as a mechanism that is both compliant enough to execute the opening and closing of the jaws of a grasper and stiff enough to grip with sufficient force, or, similarly, a device with sufficient compliance to perform the shearing motion of scissors while also supplying sufficient cutting force. The design requirement then becomes one of maximum compliance in the path of motion plus sufficient stiffness in the direction of the output force.
• The analysis may be divided into two separate loading cases: case C for cutting and case G for grasping. The analyses of the two load cases essentially are identical, thus the following equations will initially only consider only case C. To generate a structure having both the necessary compliance and stiffness, both loading cases C and G will be further divided into a flexibility condition and a stiffness condition. For the flexibility condition, force f_cis applied producing displacement field u_C1, and a dummy load f_dCis applied at the output point producing virtual displacement field v_C. The mutual potential energy (MPE) is used as a measure of flexibility, where maximizing MPE results in a compliant solution with the deflection at the point of interest maximized in the desired direction. Note that simply designing for minimum strain energy will result in a solution with maximum stiffness where all element areas are at the upper bound, thus it is desirable to design for a compromise solution of minimum strain energy and maximum mutual potential energy. MPE is a function of the stiffness matrix K₁, the actual displacement u_C1and the virtual displacement v_C, and it is defined as in (1):$\begin{array}{cc}\begin{array}{c}{\mathrm{MPE}}_C={\left(f_{\mathrm{dC}}\right)}^T·u_{C1}\\ ={\left(K_1{v}_C\right)}^T·u_{C1}\\ =v_C^T{K}_1{u}_{C1}\end{array}& \left(1\right)\end{array}$
• To analyze the stiffness condition, the same force fc is applied at the input point, but, in order to model the tool's resistance at the point where the output force is applied, the output point is now held fixed. Strain energy (SE) can be used as a measure of stiffness of the design, as is often done in structural optimization, where minimizing strain energy results in a solution with maximum resistance. Strain energy is defined as in (2), where u_C2is the actual displacement due to f_Cwhen the output point is fixed, and K_C2is the new stiffness matrix, which differs from K₁because of the additional fixed degrees of freedom.
  SE_C=(U_C2)^TK_C2u_C2  (2)
• The strain energy and mutual potential energy now represent two competing design objectives and must be combined into a single objective function using a method such as a weighted sum of SE and MPE. The weighted sum approach has its difficulties because SE and MPE may differ by orders of magnitude and thus present a scaling problem. This difficulty may be eliminated by defining the objective function, F, as a ratio of MPE to SE, which results in the objective function given by (3) (note that minimizing SE is analogous to maximizing its reciprocal 1/SE).$\begin{array}{cc}F=\mathrm{Max}\left(\frac{{\mathrm{MPE}}_C}{{\mathrm{SE}}_C}\right)=\mathrm{Max}\left(\frac{v_C^T{K}_1{u}_{C1}}{{\left(u_{C2}\right)}^T{K}_{C2}{u}_{C2}}\right)& \left(3\right)\end{array}$
• Equation (3) is the objective function for optimizing load case C, and an analogous equation is used for optimizing load case G. For a single tool to perform both C and G, we combine the functions into a single objective function using a weighted sum technique as in (4):$\begin{array}{cc}\begin{array}{c}F=\mathrm{Max}\left[\alpha \left(\frac{{\mathrm{MPE}}_C}{{\mathrm{SE}}_C}\right)+\left(1-\alpha \right)\left(\frac{{\mathrm{MPE}}_G}{{\mathrm{SE}}_G}\right)\right]\\ =\mathrm{Max}\left[\alpha \left(\frac{v_C^T{K}_1{u}_{C1}}{{\left(u_{C2}\right)}^T{K}_{C2}{u}_{C2}}\right)+\left(1-\alpha \right)\left(\frac{v_G^T{K}_1{u}_{G1}}{{\left(u_{G2}\right)}^T{K}_{G2}{u}_{G2}}\right)\right]\end{array}& \left(4\right)\end{array}$
• The scalar weighting variable Δ may then be adjusted to tweak the solution or to give more weight to a particular load case. The constraint equations for the optimization problem come from the equilibrium equations for each displacement variable (5), the limits on the design variables (6), and the maximum volume constraint (7).
• The solution procedure follows that of ground structure based topology optimization; hence, the procedure begins with a ground structure or dense web of elements. The elements' cross-sectional areas, A₁, are the optimization design variables and are assumed circular. This type of topology optimization is a special case of sizing optimization, such that the process adjusts the cross-sectional area of each element in the ground structure to obtain a solution with optimal performance. Ultimately, many of the elements' cross-sectional areas will diminish or decrease to the lower bound and the remaining elements will define the structure's topology. The formal optimization problem is now given by the objective function F in (4) and the following set of constraint equations, where l_iis element length, V* is the maximum volume of material, and N is the number of design variables.$\begin{array}{cc}\begin{array}{cc}{K}_1{u}_{C1}=f_C& K_1{u}_{G1}=f_G\\ K_1{v}_C=f_{\mathrm{dC}}& K_1{v}_G=f_{\mathrm{dG}}\\ K_{C2}{u}_{C2}=f_C& K_{G2}{u}_{G2}=f_G\end{array}& \left(5\right)\\ A_{\mathrm{lower}}\le A\le A_{\mathrm{upper}}& \left(6\right)\\ \mathrm{Vol}=\sum _{i=1}^N{A}_i{l}_i\le V^{*}& \left(7\right)\end{array}$
• A three-dimensional ground structure of frame elements is desirable as the basis for the optimization problem to allow for motions in different planes, such as multiple input and output forces and displacements that lie in orthogonal planes. The 3-D model can be set up with a ground structure of “unit cubes.” In contrast to the full ground structure that connects each node to every other node, the unit cube structure consists of a mesh of 1×1×1 cubes connected at the cube faces where each node in the cube is connected to every other node in the cube. The unit cube arrangement significantly decreases the total number of elements, which decreases computation time, while still providing acceptable solutions. The sequential linear programming technique for constrained minimization, as provided by MATLAB and similar finite element analysis programs, is desirable for solving the optimization problem. Using MATLAB's linear programming function, linprog, the linear program can be solved and used to update the values of the element areas. The step size, or maximum amount by which the areas may change for each iteration, must be limited to provide a move limit on the approximation of the linearized objective function. Convergence occurs when either the change in the objective function or the change in each design variable decreases to a critical value.
• The following example illustrates the optimization analysis used for designing the compliant multifunctional scissors-grasper tool. The setup for this problem is a 7×3×2 node design domain shown inFIG. 12 where the problem is symmetric about both the y=2 and z=0 planes, thus the figure shows only a fourth of the problem. InFIG. 12, f_Cand f_G=input forces, ΔC and ΔG=output deflections, both relative to two unique functions (e.g. cutting and grasping). The starting point (set of initial areas) was randomly generated, the areas were bounded between 0.001 and 1 cm², the maximum step size for each element in an iteration was 10% of its previous value, and unit forces were used. The weighting factor was set to 0.5 (i.e. both cases weighted equally), and essentially the same solution was obtained for all values of the volume constraint with at least a 25% volume fraction.FIG. 12 displays the result from the MATLAB program, along with the full 7×5×3 node solution (where all four symmetric sections are displayed).
• Solid modeling software, such as PTC's Pro/Engineer, can be used to generate a model that exhibits the same characteristics as the unit cube model analyzed through the MATLAB software.FIG. 13 shows a model generated by Pro/Engineer that behaves in the same manner as the unit cube model (the “full solution”) ofFIG. 12. As can be seen, the input forces fc and fG can be applied to the back side of the solid model shown inFIG. 13, and the opposite ends deflect by output displacements ΔC and ΔG (i.e. the two different output functions). It should be noted, however, that the solid model shown inFIG. 13 is made of solid titanium. As such, this solid model does not exhibit the characteristics that would be desirable for a MIS tool. In order to achieve the output displacements ΔC and ΔG desired, the input forces forces f_Cand f_Gwould have to be tremendously high. This is simply not practicable for a MIS tool. Therefore, it is desirable to have a solid model that behaves like the unit cube model ofFIG. 12, but does not require the high input forces, like the solid model ofFIG. 13, in order to achieve the output displacements necessary for MIS.
• FIG. 7 shows a second solid model generated through Pro/Engineer that behaves exactly like the models shown inFIGS. 12 and 13, but requires less input force to achieve a required output displacement. Essentially, the solid model ofFIG. 13 has been elongated to create the model ofFIG. 7. Elongating the model creates lever arms. These lever arms allow a smaller input force f_Cor f_Gto produce a greater output displacement ΔC and ΔG. The key to understanding this is realizing that the moments necessary to create the output displacements in the solid model ofFIG. 13 are generally equal to the moments created in the solid model ofFIG. 7. Because the moments are the same, the input forces necessary to achieve the desired output displacements in the solid model ofFIG. 7 are far less than the input forces in the solid model ofFIG. 13. By laws of mechanics, the greater the lever arm (moment arm or radius), the less the input force to create the same moment and resulting output displacement.
• 6. Method of Use

  	Function	Force
  	Grasping force	0.4 lb. Closing
  		0.21 lb spreading (opening)
  	Handle force	1.95 lb. Opening-cutting
  		0.5 lb closing-cutting
  		1.75 opening-grasping
  		1.5 lb. Closing-grasping
  	Pull-Off Force	0.34 lb. (using red rubber tubing)
  	Cutting Force	0.08 lb.

• The method of using tool10B has been described above. The compliant nature of tool10B provides the ability to obtain some mobility from deflection of the flexible member. Energy is stored in the flexible members of the compliant web. This can be advantageously utilized to effectuate the functions of the end effector, while the mechanism is designed so that of the user can select between multiple functions, if desired.FIGS. 16A and B illustrate the forces in the pushrods that can be used with the compliant end effector of tool10B to effect tip displacement in a simulation based on the design of tool10B. This type of use of compliant structures appear to be promising for miniaturization of MIS end effectors, because of lack of need for rigid link assembly and the potential for binding or malfunction over time when made very small. Compliant surgical instruments also tend to be easier to clean and sterilize for resposible use than traditional mechanically linked or hinged mechanisms.
• E. Exemplary Embodiment Three (Non-compliant multi-function cutting and grasping and articulating)
• 1. Structure
• FIGS. 17-22 illustrate a third exemplary embodiment according to the present invention. This tool, referred to astool10C to differentiate it fromtools10 and10B, operates similarly to the fixedlink mechanism tool10 ofFIGS. 1-3 with the following differences.
• 2. End-Effector
• Tool10C adds what will be considered a third function, namely articulation of the distal ends of both end-effector jaws. This allows the additional function of being able to articulate (in either direction from axis50) the clamping action of the end effector for greater dexterity in clamping and dissecting. Articulation of distal tips can be done independently of the clamping action or can be selectively enabled.
• Below are parameters for an example of tool20C:

  	Component	Length
  	Jaws (Total length, non-articulated)	15 mm
  	Jaws opening distance at distal ends for grasping	15 mm
  	Scissors blade length	7 mm
  	Scissors opening distance atdistal ends	10 mm
  	Articulated end maximum offset from	90 degrees
  	longitudinal axis of instrument

• Component Length
• The design of the end effector oftool10C is illustrated conceptually in FIGS.17A-E. The jaws are essentially mirror images of each other. Therefore, forembodiment10C, the top jaw inFIG. 17A will be generally indicated byreference number60, and the bottom jaw byreference number60′.
• FIGS. 17A and B show howjaws60 and60′ operate in a first mode; a clamping mode where thedistal tips68 and68′ of each jaw are straight. Eachjaw60 and60′ has abase section62 or62′ pivotally mounted alongaxis52 todistal end18 ofshaft14.Base sections62 and62′ are adapted to pivot in a plane defined by axes50and52 in response to actuation, e.g. linear movement from a sub-shaft, such as will be described later. As shown inFIGS. 17A and B, this allows jaws to function as clamping members when base and moveable sections of each jaw are aligned alongaxis50. By linear action of a sub-shaft or other member extending from ahandle12 to proximal ends ofjaws60 and60′,jaws60 and60′ can be moved between closed clamping position (FIG. 17A) and opened clamping (or dissecting) position (FIG. 17B).
• FIGS.19A-C illustrate generally one way of generating clamping movement ofjaws60 and60′ with a linearly moving sub-shaft or tube (alternatively called slider230). Eachjaw60 and60′ has aproximal end232 that extends proximally ofpivot axis52 and includes anelongated slot234 or234′. Theelongated slots234 and234′ are angularly disposed relative toaxis50 and further, are in opposite directions to one another (as seen in FIGS.19A-C).
• Acommon pin236 has opposite ends which extend laterally out of the distal end ofslider230 intoslots234 and234′. Whenpin236 is in the position ofFIG. 19A (withpin236 in the proximal ends ofslots234 and234′), the distal ends ofbase sections62 and62′ ofjaws60 and60′ would be pulled into alignment withaxis50. This would closejaws60 and60′ (seeFIG. 19A). Whenslider230 moves to pushpin236 to the distal ends ofslots234 and234′,jaws60 and60′ would open (FIG. 19B).
• But further, like themoveable section68 described with respect totool10 inFIGS. 1-3, bothjaws60 and60′ have a moveable section,68 and68′ respectively, that can pivot around apivot pin70 or70′ (defining pivot axes54 and54′). The structure of thesejaws60 and60′ is such, however, thatmoveable sections68 and68′ can pivot in both directions relative to axis50 (on either side of the same). The basic principle of articulation of thetips68 of the jaw is shown by the diagrams ofFIGS. 18A and B. The two parts of the jaw (base section62 and moveable section68) are connected by a simple pin joint located on the instrument's centerline.FIG. 18C illustrates exemplary dimensions for thecombination62 and68. Therefore, independent of the opening ofjaws60 and60′ as shown inFIGS. 17D and E andFIG. 19C,sections68 and68′ could be articulated away from alignment withaxis50. As illustrated inFIGS. 17D and E andFIG. 19C, they could form an articulated clamp on either side ofaxis50, over a range of off-axis angles.
• This articulation of tips of thejaws60 and60′ is another functional mode for a MIS tool.Slider230 could be operated to close oropen jaws60 and60′ with the moveable sections articulated together in either direction to increase the flexibility and versatility of clamping action oftool10C.FIG. 18C provides an example of additional dimensional and functional parameters for one design ofarticulatable sections68 and68′.
• The articulation or rotation of the tips of the jaws may be accomplished in various ways. Two examples are mechanical actuation, or by an electromechanical interface. Others are possible. FIGS.20A-C illustrate the general principle of one example of a mechanical actuation of the articulation function.
• Attached to the tip are two tendon lines,250A and250B, that extend down the long axis of the instrument. In a normal or reference position (FIG. 20A),tip68 is extended straight from base section62 (distally along axis50). Appropriate tension on bothlines250A and B would essentially hold or locktip68 in that position. In the orientation shown in FIGS.20A-C, pulling online250A (and releasing tension online250B) will pivot thetip68 to the left around pivot pin70 (or axis54) (seeFIG. 20C). By pulling online250B (and releasing tension online250A), the tip will pivot to the right (seeFIG. 20B). Thus, be this relatively simple method, control over articulation of thetip60 or60′ of eachjaw60 and60′, in either direction, can be actuated by linear forces (e.g. fromhandle12 or otherwise).
• It is to be understood that several discrete intermediate angles could be achieved for the tip articulation. To achieve locking in intermediate pivot positions, a ratchet-type mechanism can be used. In a prototype embodiment, a standard socket wrench was used. The two tendons were attached on either side of the socket wrench such that the two connection points and the pivot point of the wrench are in line. When the wrench was turned to one side it simultaneously released tension of one line while applying tension to the other. This resulted in required force to pivot the tip being supplied, while still maintaining tension in both tendons. In practice, such an optional locking mechanism would be integrated into the device.
• FIG. 20D illustrates in more detail how the distal ends of the tendon lines could be attached to atip68.Steel cables250A and250B could be soldered or otherwise attached (seepoints251 and253 respectively) to opposite sides of the distal end of amoveable section68 of ajaw60.Cables250A and250B could extend proximally back fromend effector20, throughshaft14, to handle12. As illustrated in FIGS.20A-D,cables250A and250B act as tendon lines. By pulling online250B,tip68 will move to the right from the viewpoint ofFIG. 20B. Pulling online250A will movetip68 to the left (FIG. 20C). If bothlines250A and250B are maintained at relatively equal lengths, and in tension,tip68 will align withaxis50.
• The same structure could be used with the other jaw,60′, such that eachjaw60 and60′ would have two cables,250A and B, and250A′ and250B′ respectively, that extend back throughshaft14 to an actuator mechanism.FIG. 20E shows that instead of having two cable ends and two solder points pertip68, a single cable could simply be formed in a U-shape at its middle and soldered at asingle point251B, and with opposite free ends extended to handle12, and connected to appropriate concentric tubes. Thus, by suitable user controls (preferably in or around handle12), the articulation of thedistal tip68 of bothjaws30 and60 can be controlled.
• By appropriate control and actuating mechanisms, the user could closejaws60 and60′ together (as inFIG. 17A), and by concurrently pullingcable250A of onejaw60 or60′, andcable250B of theother jaw60′ or60,tips68 and68′ would articulate in opposite angular directions (as inFIG. 17C). Reversing the process, i.e. pullingcable250B ofjaw60 andcable250A ofjaw60′, would movetips68 and68′ back to the position ofFIG. 17A. Thus, scissors action can be accomplished.
• Alternatively, to simplify a scissors function, onetip68 or68′ could be maintained in a straight position aligned withaxis50, and theother tip68′ or68 articulated angularly outward, by pulling on theappropriate cable250A or250A′, and then bringing the tip back by pulling theother cable250B or250B′.
• 3. Handle
• Manually actuated operation of the grasp (straight ends) mode, grasp (articulated ends) mode, or cutting mode could be accomplished by various ways. The linear push rod actuation of grasping movement forjaws60 and60′ could be as shown and described with respect to FIGS.19A-C, the common pin in slots arrangement. Rotational motion fromhandle14 could be translated to linear motion in a number of ways, including ways previously discussed.
• Articulation of tips left or right, and the cutting action could be actuated by appropriate linkage to convert rotational motion ofhandle24 to pulling forces on any of the four cables ortendon lines250A,250B,250A′ or250B′, either alone or in combination. Additionally, a variety of ways exist for holding a tendon line in tension when a companion tendon line is being pulled.
• One specific example of a system for actuating the three functions discussed above is illustrated with reference to FIGS.21A-C and22A-E, which illustrate a control and manual actuation mechanism to provide both clamping action according to linear movement of a push rod orslider230 such as shown in FIGS.19A-B, articulation oftips68 and68′ for articulated clamping as shown inFIG. 19C by manipulation of cables attached totips68, and scissors action by manipulation of cables attached to onetip68 or68′.
• As described, a notable feature ofmechanism10C is the combination of cutting, grasping and articulating into a single multi-functional instrument. The end-effector20 shown inFIGS. 17-22 is comprised of anupper jaw60 andlower jaw60′, each having a front ortip section68 or68′ andrear section62 or62′. The front and rear sections are connected with a pin joint (along axis52) to allow for rotation in the orthogonal plane to the grasping motion. The front and rear sections together form15 mm grasping jaws, while the front7mm section68 or68′ alone can be articulated to introduce articulated grasping or cutting features to the device. The grasping motion is operated by a push rod and pin in slot mechanism connected in the rear of the end-effector jaws as shown in FIGS.19A-C. The cutting and articulation motions are operated using four steel cables (250A and B,252A and B) soldered to the front portions of the end-effector jaws (two for eachjaw60/60′).
• Thehandle12 also contains some notable mechanisms. As further described below, the four cables from the end-effector connect to the front end of fourconcentric tubes350A and B, and352A and B, placed around the grasping push rod orslider230. The top notch of vertical fork(s) of sliding links mates with the disk at the rear of each tube and pull or free the cable(s) or push rod required for each function to operate. The concentric tubes were designed to allow the end-effector shaft to rotate freely without twisting the cables around the shaft itself. This type of connection provides a mechanical coupling between the rotational motion of the shaft and the linear motion of the sliding links to actuate the cables and push rod at any angular position of the end-effector.
• More specifically, handle12 ofFIG. 21 includes the following primary parts.
• A sub-shaft (or push rod or slider)230 that is rotatably supported inhollow shaft14 between a proximal end near the rear ofhandle housing12 and a distal end that is connected tojaws60 and60′ in the manner of FIGS.19A-C. Sub-shaft230 extends out ofhandle12 and throughshaft14 to endeffector20. Like the configuration of FIGS.19A-C, atransverse pin236 in the distal end ofsub-shaft230 cooperates withslots234 and234′ in the proximal ends ofjaws60 and60′ so that linear movement ofsub-shaft230 causes opening and closing ofjaws60 and60′ in clamping mode. Awheel control28, fixedly mounted onsub-shaft230, allows the surgeon to rotateend effector20 three hundred sixty degrees relative toaxis50.
• Fourtubes350A,350B,352A and352B are concentrically mounted aroundsub-shaft230 and are slideable alongsub-shaft230. At the proximal end of eachtube350A,350B,352A and352B is fixed adisc341,343,345, and347, respectively, each of which is rigid to and moves with its respective tube. At the distal end of eachtube350A,350B,352A and352B is aflange342,344,346, and348 respectively, which is rigid to and moves with its respective tube.Cables250A,250B,252A and252B, are fixed (e.g. by soldering or clamped by a screw) toflanges342,344,346, and348 respectively.Flanges342,344,346, and348 are preferably rotationally offset or radially offset relative to centerline50 so that there is open space between each cables exit from the proximal end ofshaft14 to its respective flange.
• As can be appreciated, this arrangement provides each cable a terminating structure inhandle12 that is moveable only linearly and generally parallel toaxis50. Therefore, any of the four cables can be pulled by sliding the appropriate concentric tube alongsub-shaft230. Thus, articulation control, in both directions, for eithertip68 or68′ is available at handle, and articulate can be effected through linear motion.
• Moreover, each tube is independently slideable. Therefore, any combination of articulation oftips68 and/or68′ is possible through the movement of any one or more of the tubes, alone or in combination. Still further,wheel control26 allows rotation of the orientation ofjaws60 and60′, and thus theirtips68 and68′ at the end effector over a complete360 degrees range, Without any tangling of the cables because the tubes can freely move along with subshaft when rotated.
• Actuation of a grasping action forjaws60 and60′ can be effectuated by linear movement ofsub-shaft230 alongaxis50. One way is by movingcontrol wheel26 alongaxis50, or otherwise applying forces that cause sub-shaft230 to move alongaxis50. This action could be accomplished by a wide variety of methods, including those previously discussed herein, both manual and motor or actuator driven.
• Control of actuation oftips68 and/or68′ can similarly be achieved through a wide variety of methods, manual or automated. The specifics and complexity can be left to the designer based on considerations deemed relevant.
• One example of a system for providing actuation of grasping (straight ends), grasping (articulated end(s)), and cutting, is illustrated atFIGS. 21A-22E, with particular reference to FIGS.21A-C.
• Handle22 is fixed to thehandle housing12.Handle24 is rotatably mounted tohousing12, and rotates towardshandle22 aroundpivot axis25.Handle24 includes akey slot410 which receives and retains thekey head412 at one end ofhandle link402. Theother end414 oflink402 is T-shaped.
• A set of three what will be called slidinglinks370,380 and390 fit side by side incage406.
• A combination articulation and cut/grasp switch400 has opposite heads420 and422 joined by a reduced size intermediate section424. Twotongues426,428 extend from the top side of intermediate section424.Tongue426 is the width of a single sliding links andtongue428 is the width of2 sliding links. There is a gap between these2 tongues the width of on sliding link.
• The geometry of each slidinglink360,370, and380 is illustrated inFIGS. 21B and C.
• Shortest link360 includes avertical fork361 with aslot362 sized to slideable receive the thickness ofcontrol wheel26, aproximal arm363 with a T-slot364 sized to sliceable receive T-head414 ofhandle link402; and adistal arm365 including a cut-out366 sized to sliceable receivetongue426 ofswitch400. The length oflink360 betweenends363 and365 is much shorter than the length ofcage406, so thatlink360 can slide independently oflinks370 and380, and withincage406.
• Middle slidinglink370 is similar to link360 relative to its vertical fork and slot371/372, its proximal arm and t-slot373/374, and a middle section with bottom cut-out375/376. The main differences are thatfork371 is farther distally thanfork361, and adistal leg377 extends farther distally and includes asecond fork378 having aslot379.Fork378 is also pivotally connected atpivot393 toarm377, and pivots aroundpoint392 in a parallel plane to the plane defined byfork371arm373 andarm377. Furthermore,fork378 is pivotally pinned to handlehousing12 at its middle (see pivot pin hole393). Thus,fork378 can not move as a whole with slidinglink370, but pivots when slidinglink370 slides.
• Slidinglink380 is similar to link370 relative to its vertical fork and slot381/382, its proximal arm and t-slot383/384, and a middle section with bottom cut-out385/386, and adistal leg387 extending distally and including asecond fork388 having aslot378 withfork388 being pivotally connected atpivot394; andfork388 is pivotally pinned at395 tohousing12, likefork378. The main differences are thatfork381 is farther distally thanfork371.Fork388 is spaced the same distance fromfork381 asfork378 is from fork271.
• When assembled, intermediate portion424 ofswitch400 is positioned laterally incage406 in alignment with the longitudinal slots along the sides ofcage406, with opposite heads420 and422 ofswitch400 positioned outside on opposite sides ofcage406. Therefore, any movement ofswitch406 lateral toaxis50 will cause following movement ofcage406. Slidinglinks360,370, and380 are placed side-by side through the open top ofcage406 in the order shown inFIG. 21B, and with cut-outs366,376, and386 aligned with intermediate section424 ofswitch400. In such position, eachproximal end363,373,383 oflinks360,370, and380 are laterally aligned at the rear end ofcage406.
• End guide405 is installed in the rear end ofcage406 as shown inFIG. 21. It has an opening through which can pass T-head414 oflink412, but serves to support and guide the middle oflink402, which would extend generally straight back to its connection to slot410 inhandle24. End guide does not allow lateral movement of T-head414 relative tocage406. Cover404 would be installed overcage406, which has a longitudinal slot through whichforks361,371,379,381, and388 extend. Also, cover would be fixed against movement by connection to the body ofhandle12.
• This sub-assembly of cage, sliding links, and switch is supported inside handlehousing12 in a manner that allow it to move laterally somewhat, but not along its longitudinal axis, which would be parallel to sub-shaft230 andaxis50 oftool10C. But further, slidinglinks360,370, and380 can slide longitudinally withincage406; link360 substantially, link370 less, and link380 less, as their opposite ends limit such travel.
• Still further, switch400 can slide transversely of the longitudinal axis ofcage406, but when atongue426,428, or230 is aligned with a cut-out366,376, or386, the respective sliding link(s) can not slide longitudinally ifswitch400 is held against longitudinal movement, or the respective sliding link(s) move is correspondence with longitudinal movement ofswitch400. Conversely, if a tongue is not aligned with such a cut-out, that sliding link can slide longitudinally relative to switch400. The respective link(s) simply slide over the middle section ofswitch400 as no tongue impedes such movement.
• FIGS. 21A and C show the relationship of the slidinglinks360,370, and380 withconcentric tubes350A,350B,352A, and352B whentool10C is assembled. When assembled,notches362,372,382,379 and389 are positioned to receive the edge ofcontrol wheel26,disc345,disc343,disc347, anddisc341, respectively, allowing rotation but not longitudinal movement of the same, unless the sliding link of the respective notch is moved along its allowed path of travel. This arrangement puts control over grasping action of the tool jaws by control of movement of slidinglink360, because such movement controls longitudinal movement ofsub-shaft320. It puts control over articulation oftips68 and68′ by control of movement of slidinglinks370 and/or380 because such movement controls pulling ofcables350A and B and352A and B, which control left and right concurrently articulation oftips68 and68′. It puts control over cutting action by control of movement of slidinglink370, because such movement controls pulling ofcables350A and B which controls articulation movement of onetip68 away from and back to fixedtip68′ to effectuate scissors action.
• The logical organization of thismulti-functional tool10C can be shown with reference to the state diagrams of FIGS.22A-E.
• Straight end grasping mode: Handle24 is moved to its end limit closed to fixedhandle22.Switch400 is moved laterally so that slidinglink370 is positioned in the gap betweentongues426 and428 and cut-outs376 and386 are aligned withtongue428. This lateral motion ofswitch440 also pulls end414 oflink402 into t-slot364 oflink370 therefore providing a linkage fromlink370 throughlink402 to410 the moving handle., Thus,tips68 and68′ would be straight (aligned along axis50).Switch400 is pulled all the way out. The geometries are configured so that this action will pullcage406, and thus all oflinks360,370, and380, to a position that aligns T-head414 with T-slot364 inlink360. This also hascontrol wheel26 to its rearmost position, and thus, likewise, sub-shaft230. As indicated inFIG. 22A,tips68/68′ would therefore be straight, aligned and closed (gripping action--jaws closed).
• Thus, switch400 can slide back and forth alongslot410 which lengthens and shortens the cables, but the tongues in the cut-outs make both slidinglinks370 and380 slide together, the same direction and the same distance. This therefore causes any articulation oftips68 and68′ to be concurrent and in the same direction. Articulation can be either to the left or right, and over a range from straight to maximum angle. But further, sincelink360 is linked to handle24,jaws60 and60′ can be opened and closed, even whentips68/68′ are articulated, by movement ofhandle24. SeeFIG. 22B.
• Compare then the scissors mode:Switch400 is moved front or back to an intermediate position between fully forward and fully backward.Cage406 is moved laterally by pushingswitch400 laterally such that T-head414 is now in T-slot374 of slidinglink370. During cutting mode,tongue426 is located inslot366 oflink370, link380 is located in the gap betweentongues426 and428, andtongue428 is located inslots376 and386 oflinks380 and390. and head420 ofswitch400 is captured against longitudinal movement inslot440; effectively lockinglinks360 and380 from sliding or moving (and thus locking out grasping or articulation oftip68′). Therefore, rotational movement ofhandle24 would translate into linear movement oflink402, which would slide slidinglink370, which slidesconcentric tubes352A and352B, which are connected tocables252A and252B (both sides oftip68′). Forward movement ofhandle24 towardshandle22, causes rearward movement oflink402 and slidinglink370, causes rearward sliding oftubes352A and due to the reversing pivoting motion of378, forward motion of352B is produced Slidinglinks360 and380 are locked in place, so tip68 stays in a straight position. Opposite movement ofhandle24 produces an opposite action. This process can be repeated to repeat scissors action. SeeFIG. 22C.
• The preferred feature of disallowing articulation when cutting is accomplished by the fact that a section of400 is rigidly captured in opening442 preventing any forward or rearward sliding motion of thearticulation switch400. On the other hand, the functionality ofswitch400, in combination with the sliding links, allows articulation (if desired), during clamping action, by allowing slidinglinks370 and380 to move (in unison) while slidinglink360 is connected to handlelink402. The surgeon merely adjustsswitch400 forward/rearwardly alongslot440, and slides switch400 one way alongslot440 for articulation oftips68/68′ in one direction relative toaxis50, and the other way for articulation the other way.
• Thus, actuation ofmulti-function tool10C is accomplished by manual manipulation ofmulti-action switch400 andmoveable handle24. Switching of articulation/function toggle switch400 between2 lateral positions sets whethertool10C is in grasping or cutting mode. While in cutting mode, articulation is not allowed by the physically blocking of the forward/rearward motion of the articulation switch by400's position inslot442. Articulation is possible during grasping mode when400 is not engaged inslot442 and forward motion of400 inslot440 is allowed. Sliding400 forward and rearward operates articulation. Pivotinghandle24 operates cutting or grasping.
• 4.Shaft14
• Shaft14 can be similar or the same to those previously discussed, or some other way of translating appropriate motion to the end effector can be used.
• 5. Method of Use
• While in grasping mode,end effector20 can also be articulated to the left or right by sliding the articulation switch forward or backward. During cutting, the articulation feature is disabled. To avoid accidental switching between functions, the toggle switch can only be switched between cutting and grasping when the jaws of the instrument are in the closed, unarticulated position.
• A prototype oftool10C accomplished the following:

  	Function	Force
  	Grasping force	1.1 lb
  	Force Input at Handle	9.0 lb
  	Pull-Off Force	2.3 lb. (using red rubber tubing)
  	Cutting Force	1.4 lb

• F. Options and Alternatives
• It will be appreciated that the present invention can take many forms and embodiment. The included exemplary embodiments are given by way of example only, and not by way of limitation to the invention, which is solely described by the claims herein. Variations obvious to one skilled in the art will be included within the invention defined by the claims.
• For example, the concepts of the invention are applicable to laparoscopy, but can also be applied to other MIS techniques and/or procedures requiring similar advantages. Examples include, but are not limited to, gynecology, urology, thoracic, arthroscopy, ENT, pediatric, neurosurgery.
• Furthermore, the invention can be applicable to developing procedures. A few examples include robotic, flexible scopes, and catheter-based surgeries.
• The exemplary embodiments have been described in the context of a grasper and/or cutter. Other functions are possible. Examples are dissection (moving ends outwardly against tissue instead of grasping by closing, or using the blunt end with both jaws closed to scrape or separate tissue).
• Further, other adjunct functions can be added to the tool. One example is cauterization (by electrification of at least one tip end). Others include such things as irrigation, suction, or other functions, which could be delivered to the internal surgical site with the device (e.g. by attaching the distal end of an irrigation or other tube or delivery conduit to an articulatable jaw member).
• In-between maximum rotation and the straight position of the articulating tips, structure could be used to allow the tool to lock into a plurality of intermediate positions. Some type of ratcheting system (operating like a ratchet wrench), might be used to accomplish this. Or there could be some infinitely variably adjustable mechanism to allow the surgeon the ability to lock the tip at any angle between end limits.
• Other means of actuating the articulation and opening/closing of jaws themselves may be employed. For example, the tendon wire/ratchet mechanism discussed could be replaced with a more compact mechanism for mechanical actuation. The articulation and jaw opening/closing might also be accomplished by small electromechanical actuators controlled by the surgeon using a trigger or other input device on the tool handle.
• Any of the embodiments, pin-jointed or compliant, could utilize mechanical link joint and/or compliant actuation.

Claims (35)

1. An end-effector for utilization at a surgical site on or in a patient comprising:

(a) a working end adapted for surgical functioning and including an interface adapted for operative connection to an actuating mechanism;

(b) said working end being configurable to

(1) a first state capable of a first surgical function by translation of one portion of the working end towards another portion of the working end in a first direction;

(2) a second state capable of a second surgical function by translation of the one portion of the working end towards another portion of the working end in a second direction;

(3) wherein selection of said first or second state is effected through said interface.

2. The end-effector ofclaim 1 wherein said interface comprises a non-compliant mechanism.

3. The end-effector ofclaim 1 wherein said interface comprises a compliant mechanism.

4. The end-effector ofclaim 1 wherein said one portion comprises a first grasping surface moveable in a first plane.

5. The end-effector ofclaim 4 wherein said another portion is a second grasping surface having a section in said first plane and having a section that is moveable outside of said first plane.

6. The end-effector ofclaim 1 wherein said one portion is a first jaw pivotable in a first plane and said another portion is a second jaw positionable in said first plane.

7. The end-effector ofclaim 6 wherein said portion of said second jaw is pivotable in a second plane.

8. The end-effector ofclaim 1 wherein said first surgical function is grasping and said second surgical function is cutting action.

9. The end-effector ofclaim 1 further comprising a third state for a third surgical function.

10. The end-effector ofclaim 9 wherein the third surgical function is articulation of the working end.

11. The end-effector ofclaim 1 in combination with an actuating mechanism.

12. The end-effector ofclaim 9 wherein said first surgical function comprises grasping and said third state comprises articulation of said grasping function relative to a reference position.

13. The end-effector ofclaim 1 wherein the end-effector is adapted for minimally invasive surgery.

14. A method of providing multiple surgical functioning at a surgical site on or in a patient comprising:

(a) configuring a working end of a surgical tool for a first surgical function by translation of the one portion of the working end towards another portion of the working end in a first direction;

(b) reconfiguring the working end for a second surgical function without exchange of said working end by translation of the one portion of the working end towards another portion of the working end in a second direction.

15. The method ofclaim 14 wherein selection of said first or second surgical functions is effected through an interface.

16. The method ofclaim 14 wherein said interface comprises a non-compliant mechanism.

17. The method ofclaim 14 further comprising a third surgical function.

18. The method ofclaim 17 wherein the third surgical function is articulation of the working end.

19. A multifunction end-effector tool for use in minimally invasive surgery, comprising:

(a) a mechanism adapted to be inserted through an incision in a patient's body, the mechanism comprising;

(b) a tool head, the tool head including a pair of jaws pivotal about a first axis so as to provide a first function and pivotal about a second axis so as to provide a second function; and

(c) an interface adapted for operative communication with a control external of the patient's body and to an actuator operatively connected to the tool head to move the jaws in response to user input from a control.

20. The tool ofclaim 19 wherein the jaws each have a grasping surface and a cutting edge.

21. The tool ofclaim 19 wherein each jaw includes an inner end pivotal about the first axis and an outer end pivotal about the second axis.

22. The tool ofclaim 21 wherein the outer ends of the jaws are pivotable in opposite directions for the cutting action.

23. The tool ofclaim 21 wherein the outer ends of the jaws are pivotable in the same direction about the second axis to provide for articulated grasping and cutting.

24. The tool ofclaim 19 further comprising an actuator which comprises a non-compliant mechanism.

25. A surgical instrument for performing multiple surgical tasks comprising:

(a) a shaft having a proximal portion and a distal portion;

(b) a handle positioned on the proximal portion of the shaft;

(c) jaws pivotable relative to each other, positioned on the distal portion of the shaft; and

(d) an actuation system for imparting articulation motion to the jaws.

26. The surgical instrument ofclaim 25 wherein the pivotable jaws comprise multifunctional scissors, a grasper, a dissector, a cauterizer, or an irrigator.

27. The surgical instrument ofclaim 25 wherein the actuation system comprises a mechanical actuator, an electrical actuator, a pneumatic actuator, a hydraulic actuator, an electroactive material, or a combination thereof.

28. The surgical instrument ofclaim 25 wherein said instrument is configured for minimally invasive surgical tasks.

29. The surgical instrument ofclaim 25 wherein multifunctionality of the pivotable jaws is enabled by a non-compliant mechanism.

30. The surgical instrument ofclaim 25 further comprising two-part jaws pivotable relative to each other, mounted on the distal portion of the shaft, said jaws having a proximal portion and a distal tip, wherein the tips of said jaws are able to articulate in a plane perpendicular to a plane of jaw opening and closing.

31. The surgical instrument ofclaim 30 wherein the jaw actuation system is electrically linked to an electroactive material embedded within, bonded to, or connected to the two-part jaws for effecting movement of the jaws from a closed position to an actuated position; for retaining the jaws in the actuated position; and for enabling the jaws to return to the closed position.

32. The surgical instrument ofclaim 25 wherein the actuated system comprises a cutting, dissecting, or grasping configuration.

33. The surgical instrument ofclaim 26 wherein the jaws are able to be articulated simultaneously or independently.

34. The surgical instrument ofclaim 26 wherein multifunctionality of the pivotable jaws is enabled by a compliant mechanism.

35. The surgical instrument ofclaim 34 further comprising a static balance mechanism to the actuating mechanism for the compliant mechanism.

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