Abstract:
A medical instrument having a proximal control handle and a distal tool that are intercoupled by an elongated instrument shaft that is meant to pass internally of an anatomic body, proximal and distal movable members that respectively intercouple the proximal control handle and the distal tool with the instrument shaft, cable control means disposed between the movable members, an actuation member at the handle for controlling the distal tool through the movable members, and a coupler for selectively engaging or disengaging the shaft portion of the instrument from the handle portion. The handle has a distal receiver portion, and a shaft connector on said proximal motion member is selectively engageable with and releaseable from the receiver portion.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates in general to medical instruments, and more particularly to manually-operated surgical instruments that are intended for use in minimally invasive surgery or other forms of surgical or medical procedures or techniques. The instrument described herein is primarily for a laparoscopic procedure, however, it is to be understood that the instrument of the present invention can be used for a wide variety of other procedures, including intraluminal procedures. 
       BACKGROUND OF THE INVENTION 
       [0002]    Endoscopic and laparoscopic instruments currently available in the market are extremely difficult to learn to operate and use, mainly due to a lack of dexterity in their use. For instance, when using a typical laparoscopic instrument during surgery, the orientation of the tool of the instrument is solely dictated by the location of the target and the incision. These instruments generally function with a fulcrum effect using the patients own incision area as the fulcrum. As a result, common tasks such as suturing, knotting and fine dissection have become challenging to master. Various laparoscopic instruments have been developed over the years to overcome this deficiency, usually by providing an extra articulation often controlled by a separately disposed control member for added control. However, even so these instruments still do not provide enough dexterity to allow the surgeon to perform common tasks such as suturing, particularly at any arbitrarily selected orientation. Also, existing instruments of this type do not provide an effective way to hold the instrument in a particular position. Moreover, existing instruments require the use of both hands in order to effectively control the instrument. 
         [0003]    An improved instrument is shown in U.S. Pat. No. 7,147,650 having enhanced dexterity and including, inter alia, a rotation feature with proximal and distal bendable members. Even though this instrument has improved features there remains the need for a more economically feasible instrument, and one in which the handle can be re-used while the tip of the instrument is disposable or reposable. 
         [0004]    Accordingly, an object of the present invention is to provide an improved laparoscopic or endoscopic instrument in which a portion of the instrument is re-useable and a portion is disposable. In embodiments described herein the handle end of the instrument is re-useable and the distal portion or tip of the instrument is disposable. By being able to re-use the handle portion, the instrument is more economically feasible. 
         [0005]    A further object of the present invention is to provide an improved laparoscopic or endoscopic surgical instrument that allows the surgeon to manipulate the tool end of the surgical instrument with greater dexterity. 
         [0006]    Another object of the present invention is to provide an improved surgical or medical instrument that has a wide variety of applications, through incisions, through natural body orifices or intraluminally. 
         [0007]    Another object of the present invention is to provide a locking feature that is an important adjunct to the other controls of the instrument enabling the surgeon to lock the instrument once in the desired position. This makes it easier for the surgeon to thereafter perform surgical procedures without having to, at the same time, hold the instrument in a particular bent configuration. 
         [0008]    Still another object of the present invention is to provide an improved medical instrument that is characterized by the ability to lock the position of the instrument in a pre-selected position while enabling rotation of the tip of the instrument while locked. 
         [0009]    Still another object of the present invention is to provide an improved medical instrument that can be effectively controlled with a single hand of the user. 
       SUMMARY OF THE INVENTION 
       [0010]    In accordance with the present invention there is provided a surgical instrument that includes: an instrument shaft having proximal and distal ends; a tool disposed from the distal end of the instrument shaft; a control handle coupled from the proximal end of the instrument shaft; a distal motion member for coupling the distal end of the instrument shaft to the tool; a proximal motion member for coupling the proximal end of the instrument shaft to the handle; actuation means extending between the distal and proximal motion members for coupling motion of the proximal motion member to the distal motion member for controlling the positioning of the tool; the handle having a distal receiver portion; a shaft connector on the proximal motion member selectively engageable with and releaseable from the receiver portion; and an actuation cable extending from the shaft connector to the tool for controlling the actuation of the tool. 
         [0011]    In accordance with other aspects of the present invention the surgical instrument further includes a rotation means disposed adjacent the control handle and rotatable relative to the control handle for causing a corresponding rotation of the instrument shaft and tool; at least the proximal motion member comprises a proximal bendable member, the rotation means comprises a rotation knob that is adapted to rotate the tool about a distal tool roll axis and the rotation knob is disposed between the control handle and proximal bendable member; an actuation lever may be supported from the handle at a pivot point on the handle, a linkage mechanism controlled from the actuation lever and a cable engagement member controlled from the linkage mechanism for capturing a lug at the proximal end of the actuation cable for controlling the actuation cable and, in turn, the tool; the linkage mechanism may include a ratchet and pawl mechanism that provides successive lever positions for controlling the force applied at the tool and a plurality of connected links one of which includes a split link having a biasing spring therebetween; the cable engagement member may comprise a carriage that supports a gate that is movable transverse to the longitudinal axis of the carriage so as to capture the cable lug; a spring for biasing the gate and a cam block that is engageable with the gate to open the gate to enable the cable lug to be released; a locking mechanism for fixing the position of the tool at a selected position and having locked and unlocked states, the locking mechanism including a ball and socket arrangement disposed about the proximal motion member and a cinch member for locking the ball and socket arrangement; the socket member may comprises a split socket and the cinch member closes the split socket to lock the socket on the ball; a set of clamping blocks, the cable having distal of the lug a flange that is captured by the clamping blocks, the clamping blocks operated from a release member at the proximal end of the handle; including a sleeve member, a linkage member for controlling the transition of the sleeve member from the release member, the sleeve member controlling the clamping blocks to move toward and away from each other in providing the clamping action at the cable flange; including an actuation lever supported from the handle at a pivot point on the handle, the actuation cable having separable proximal and distal cable portions, the proximal cable portion controlled from the actuation lever, the distal cable portion selectively engageable or releaseable with respect to the proximal cable portion; including a cable locking mechanism for engaging the cable portions and a shaft locking mechanism for retaining the shaft connector; wherein the cable locking mechanism may include a sleeve and a release button mounted on the handle, and a connector at the distal end of the proximal cable portion that has multiple fingers for selective engagement with a lug on the distal cable portion so as to capture the cable lug, and wherein the shaft locking mechanism includes a gate and a release lever mounted on the handle, the gate for capturing a post on the distal cable portion; wherein the tool may include a collet, a removable tool member that is received in the collet and a set of jaws for holding the tool member; wherein the tool member may be a cautery tool and further including a voltage source at the handle for coupling energy to the actuation cable and an actuation lever for controlling the actuation cable which, in turn, controls the set of jaws for grasping the tool member; and wherein the tool may comprise a rotary cutter and further including a motor on the handle for controlling the rotary cutter via the actuation cable, and an actuation lever for controlling the actuation cable. 
         [0012]    In accordance with the present invention there is also provided a medical instrument having a proximal control handle and a distal tool that are intercoupled by an elongated instrument shaft that is meant to pass internally of an anatomic body, proximal and distal movable members that respectively intercouple the proximal control handle and the distal tool with the instrument shaft, cable control means disposed between the movable members, an actuation member at the handle for controlling the distal tool through the movable members, a tool coupler for selectively engaging or disengaging the distal tool and a control member mounted at the handle for controlling the tool coupler. 
         [0013]    In accordance with still other aspects of the present invention the medical instrument the tool coupler may includes a collet and a jaw member that transitions relative to the collet for receiving the distal tool and the collet may be attached to the proximal movable member, the proximal movable member comprises a proximal bendable member and the jaw member comprises a set of fingers extending from a base. 
         [0014]    In still another embodiment there is provided a method of controlling a medical instrument that has a proximal end including a control handle and a distal end including a distal tool, the control handle and distal tool being intercoupled by an elongated instrument shaft and the tool actuated from a tool control cable that is operated from an actuation lever at the handle, the method including providing proximal and distal movable members that respectively intercouple the proximal control handle and the distal tool with the instrument shaft, the proximal and distal movable members being intercoupled so that a motion at the proximal movable member controls the distal movable member, and supporting the proximal movable member for removable interlock with a receiver portion at the handle. 
         [0015]    In accord with other aspects the method may include dividing the tool control cable into separate cable segments and interlocking the separate cable segments so that the tool control cable is operable or manually controlling, from the proximal end of the instrument, the rotation of the distal tool about its longitudinal distal tool axis. 
         [0016]    In still another embodiment the instrument has a proximal control handle and a distal tool that are intercoupled by an elongated instrument shaft, proximal and distal movable members that respectively intercouple the proximal control handle and the distal tool with the instrument shaft, means disposed between the movable members so that a motion at the proximal movable member controls the distal movable member and, in turn, the distal tool, means supported at the handle for controlling the distal tool including a tool control cable that extends between the proximal movable member and the distal tool and an actuation lever mounted at the handle, the handle having a distal receiver portion, and a shaft connector on the proximal movable member selectively engageable with and releaseable from the receiver portion. 
         [0017]    In accordance with other aspects the tool control cable may include separate control cable segments that are adapted to have one of an engaged state and a disengaged state and a control member may be included at the control handle and manipulable by a user to control, via the proximal and distal movable members, the rotation of the distal tool about its distal tool axis. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0018]    Numerous other advantages can be realized in accordance with the present invention by referring to the accompanying drawings, in which: 
           [0019]      FIG. 1  is a perspective view of a first embodiment of a surgical instrument constructed in accordance with the present invention with a disposable shaft portion and a reusable handle portion, and illustrating the instrument in use; 
           [0020]      FIG. 2  is a cross-sectional side view of the instrument of  FIG. 1  with the actuation lever at rest and showing the jaws open; 
           [0021]      FIG. 3  is an enlarged cross-sectional side view of the instrument of  FIG. 1  and showing the instrument in use with the jaws at least partially closed; 
           [0022]      FIG. 4  is an exploded fragmentary cross-sectional view illustrating the shaft removed from the handle; 
           [0023]      FIG. 5  is a somewhat schematic cross-sectional detail view of the shaft locking means of the handle engaging the end of the shaft and with the cable engagement means at rest or unengaged; 
           [0024]      FIG. 5A  is a fragmentary detail view of the cable engagement means of  FIG. 5  illustrating the cable lug being engaged; 
           [0025]      FIG. 6  is a cross-sectional view similar to that shown in  FIG. 5  but illustrating the cable lug being pulled proximally; 
           [0026]      FIG. 7  is a fragmentary cross-sectional view showing the cable lug released and the shaft locking means disengaged from the shaft; 
           [0027]      FIG. 8  is an exploded cross-sectional view similar to  FIG. 7  but showing the instrument shaft removed from the handle; 
           [0028]      FIG. 9  is an exploded perspective view of the shaft locking means and the cable engagement means disengaged; 
           [0029]      FIG. 10  is a partially broken-away perspective view of the shaft and cable engagement means; 
           [0030]      FIG. 11  is a partially broken-away perspective view of the cable engagement means by itself and in use; 
           [0031]      FIG. 12  is a schematic side view of an alternate embodiment of the instrument adapted for use as a cauterization tool and employing a removable tip; 
           [0032]      FIG. 12A  is an end view of the tool clamping or holding means of  FIG. 12 ; 
           [0033]      FIG. 12B  is a cross-sectional side view taken along line  12 B- 12 B of  FIG. 12A ; 
           [0034]      FIG. 13  is a fragmentary cross-sectional side view of the shaft and cable engagement means of  FIG. 12 ; 
           [0035]      FIG. 14  is a cross-sectional view taken along line  14 - 14  of  FIG. 13  and illustrating the shaft locked; 
           [0036]      FIG. 15  is an exploded cross-sectional view of the instrument of  FIG. 12  showing the shaft removed from the handle; 
           [0037]      FIG. 16  is a partially broken-away perspective view of the alternate instrument showing the cable engagement means by itself and in an engaged position; 
           [0038]      FIG. 17  is an exploded perspective view similar to that shown in  FIG. 16  but showing the cable engagement means released; 
           [0039]      FIG. 18  is a schematic side view of a further alternate embodiment of the instrument adapted for use as a rotary cutting tool; 
           [0040]      FIG. 18A  is an end view of the tool clamping means of  FIG. 18 ; 
           [0041]      FIG. 18B  is a cross-sectional view taken along line  18 B- 18 B of  FIG. 18A ; 
           [0042]      FIG. 18C  is a fragmentary cross-sectional side view of the cable engagement means of  FIG. 18 ; 
           [0043]      FIG. 19  is a partially broken-away perspective view of the cable engagement means of  FIG. 18  by itself and in an engaged position; and 
           [0044]      FIG. 20  is an exploded perspective view showing the cable engagement means of  FIG. 19  released. 
       
    
    
     DETAILED DESCRIPTION 
       [0045]    The present invention is illustrated in the drawings as a surgical instrument that has two portions such that a detachable instrument shaft portion may be disposable and a re-usable handle portion may be sterilized and reused numerous times. This allows for a higher quality instrument handle portion while keeping the overall price of the instrument reasonable. 
         [0046]    The instrument of the present invention may be used to perform minimally invasive procedures. “Minimally invasive procedure,” refers herein to a surgical procedure in which a surgeon operates through a small cut or incision, the small incision being used to access the operative site. In one embodiment, the incision length ranges from 1 mm to 20 mm in diameter, preferably from 5 mm to 10 mm in diameter. This procedure contrasts those procedures requiring a large cut to access the operative site. Thus, the flexible instrument is preferably used for insertion through such small incisions and/or through a natural body lumen or cavity, so as to locate the instrument at an internal target site for a particular surgical or medical procedure. The introduction of the surgical instrument into the anatomy may also be by percutaneous or surgical access to a lumen, vessel or cavity, or by introduction through a natural orifice in the anatomy. 
         [0047]    In addition to use in a laparoscopic procedure, the instrument of the present invention may be used in a variety of other medical or surgical procedures including, but not limited to, colonoscopic, upper GI, arthroscopic, sinus, thorasic, prostate, transvaginal, orthopedic and cardiac procedures. Depending upon the particular procedure, the instrument shaft may be rigid, semi-rigid or flexible. 
         [0048]    Although reference is made herein to a “surgical instrument,” it is contemplated that the principles of this invention also apply to other medical instruments, not necessarily for surgery, and including, but not limited to, such other implements as catheters, as well as diagnostic and therapeutic instruments and implements. 
         [0049]    There are a number of unique features embodied in the instrument that is described herein. For example, there is provided a locking mechanism that is constructed using a ball and socket arrangement disposed about the proximal motion member that follows the bending action and in which an annular cinch ring is used to retain the ball and socket arrangement in a fixed particular position, and thus also maintain the proximal and distal bendable members in a particular bent condition, or in other words locked in that position. The cinch ring includes a locking lever that is conveniently located adjacent to the instrument handle and that is easily manipulated to lock and unlock the cinch ring and, in turn, the position of the end effector. The cinch ring is also preferably rotatable to that the locking lever can be positioned conveniently or can be switched (rotated) between left and right handed users. This lock control allows the surgeon one less degree of freedom to concentrate on when performing certain tasks. By locking the bendable sections at a particular position, this enables the surgeon to be more hands-free for controlling other degrees of freedom of the instrument such as manipulation of the rotation knob to, in turn, control the orientation of the end effector. 
         [0050]    A main feature of the present invention relates to the ability of the instrument to be partially disposable and partially re-useable. In that way the instrument cost can be substantially reduced as it is not necessary to replace the entire instrument for each procedure. In previous instrument constructions, the proximal bending member has been mounted directly to the rotation knob but now a connector and associated receiver allow the bending member to be removed from the rotation knob. In one embodiment a disconnect means is provided at the handle where the distal motion member, tool, instrument shaft and proximal motion member are separable from the handle of the instrument. This enables the distal components to be engageable and dis-engageable or releasable from the handle. The handle portion of the instrument is re-useable and thus the cost of that part of the instrument is essentially spread over several instrument uses. 
         [0051]      FIG. 1  is a perspective view of one embodiment of the surgical instrument  10  of the present invention.  FIGS. 2-11  provide further details of this embodiment.  FIGS. 12-17  illustrate a second embodiment of the present invention in which the instrument is adapted for use as a cauterization tool and employs a removable tip.  FIGS. 18-20  illustrate a third embodiment of the present invention in which the instrument is adapted for use as a rotary cutting tool. 
         [0052]    In the embodiment of  FIG. 1  both the tool and handle motion members or bendable members are capable of bending in any direction. They are interconnected via cables (preferably four cables) in such a way that a bending action at the proximal member provides a related bending at the distal member. The proximal bending is controlled by a motion or deflection of the control handle by a user of the instrument. In other words the surgeon grasps the handle and once the instrument is in position any motion (deflection) at the handle immediately controls the proximal bendable member which, in turn, via cabling controls a corresponding bending or deflection at the distal bendable member. This action, in turn, controls the positioning of the distal tool. 
         [0053]    The proximal member is preferably generally larger than the distal member so as to provide enhanced ergonomic control. In the illustrated embodiment the ratio of proximal to distal bendable member diameters may be on the order of three to one. In one version in accordance with the invention there may be provided a bending action in which the distal bendable member bends in the same direction as the proximal bendable member. In an alternate embodiment the bendable, turnable or flexible members may be arranged to bend in opposite directions by rotating the actuation cables through 180 degrees, or could be controlled to bend in virtually any other direction depending upon the relationship between the distal and proximal support points for the cables. 
         [0054]    As has been noted, the amount of bending motion produced at the distal bending member is determined by the dimension of the proximal bendable member in comparison to that of the distal bendable member. In the embodiment described the proximal bendable member is generally larger than the distal bendable member, and as a result, the magnitude of the motion produced at the distal bendable member is greater than the magnitude of the motion at the proximal bendable member. The proximal bendable member can be bent in any direction (about 360 degrees) controlling the distal bendable member to bend in either the same or an opposite direction, but in the same plane at the same time. Also, as depicted in  FIG. 1 , the surgeon is able to bend and roll the instrument&#39;s tool about its longitudinal axis to any orientation simply by rolling the axial rotation knob  24  about a rotation direction indicated in  FIG. 1  by the rotation arrow R 1 . 
         [0055]    In this description reference is made to bendable members. These members may also be referred to as turnable members, bendable sections or flexible members. In the descriptions set out herein, terms such as “bendable section,” “bendable segment,” “bendable member,” or “turnable member” refer to an element of the instrument that is controllably bendable in comparison to an element that is pivoted at a joint. The term “movable member” is considered as generic to bendable sections and joints. The bendable elements of the present invention enable the fabrication of an instrument that can bend in any direction without any singularity and that is further characterized by a ready capability to bend in any direction, all preferably with a single unitary or uni-body structure. A definition of a “unitary’ or “uni-body” structure is—a structure that is constructed only of a single integral member and not one that is formed of multiple assembled or mated components—. 
         [0056]    A definition of these bendable members is—an instrument element, formed either as a controlling means or a controlled means, and that is capable of being constrained by tension or compression forces to deviate from a straight line to a curved configuration without any sharp breaks or angularity—. Bendable members may be in the form of unitary structures, such as of the type shown herein in  FIG. 3  for the proximal bendable member, may be constructed of engageable discs, or the like, may include bellows arrangements or may comprise a movable ring assembly. In  FIG. 2  herein the unitary bendable structure includes a series of alternating flexible discs  130  that define therebetween slots  132 . A “unitary” or “uni-body” structure may be defined as one that is constructed for use in a single piece and does not require assembly of parts. Connecting ribs  131  are illustrated as extending between adjacent discs  130 . Both of the bendable members preferably have a rib pattern in which the ribs are disposed at a preferred 60 degree variance from one rib to an adjacent rib. For several forms of bendable members refer to co-pending applications Ser. No. 11/185,911 filed on Jul. 20, 2005; Ser. No. 11/505,003 filed on Aug. 16, 2006 and Ser. No. 11/523,103 filed on Sep. 19, 2006 all of which are hereby incorporated by reference herein in their entirety. 
         [0057]      FIG. 1  shows one embodiment of the instrument of the present invention. Further details are illustrated in  FIGS. 2 through 11 .  FIG. 1  depicts the surgical instrument  10  in a perspective view, as may occur during a surgical procedure. For example, the instrument may be used for laparoscopic surgery through the abdominal wall  4 . For this purpose there is provided an insertion site at which there is disposed a cannula or trocar. The shaft  14  of the instrument  10  is adapted to pass through the cannula or trocar, that is schematically illustrated at  6 , so as to dispose the distal end of the instrument at the operative site. The end effector  16  is depicted in  FIG. 1 . The embodiment of the instrument shown in  FIG. 1  is typically used with a sheath  98  covering the distal member  20  to keep bodily fluids from entering the distal bending member  20 . 
         [0058]    A separate sheath (not shown) may be temporarily used to cover the entire distal bendable member and end effector. Such a sheath is only used for shipping the instrument and may be discarded once the instrument is in place on the handle. The sheath keeps the jaws in an open position, as illustrated in  FIG. 2 , and also keeps the distal bendable member in a substantially straight position. See related application Ser. No. 11/900,417 filed on Sep. 11, 2007, which is hereby incorporated by reference in its entirety, for further details of the temporary sheath construction. By doing that the actuation cable is maintained in a particular aligned position and ready for engagement with the handle portion of the instrument. Instead of using a pre-formed sheath one may alternatively use a biasing means in the instrument to maintain a predetermined position of the instrument cable, usually one in which the jaws are maintained open. 
         [0059]    A rolling motion can be carried out with the instrument of the present invention. This can occur by virtue of the rotation of the rotation knob  24  relative to the handle  12  about a longitudinal shaft axis. This is represented in  FIG. 1  by the rotation arrow R 1 . When the rotation knob  24  is rotated, in either direction, this causes a corresponding rotation of the instrument shaft  14 . This is depicted in  FIG. 1  by the rotational arrow R 2 . This same motion also causes a rotation of the distal bendable member and end effector  16  about an axis that corresponds to the instrument tip, depicted in  FIG. 1  as about the longitudinal tip or tool axis P. In  FIG. 1  refer to the rotational arrow R 3  at the tip of the instrument. 
         [0060]    Any rotation of the rotation knob  24  while the instrument is locked (or unlocked) maintains the instrument tip at the same angular position, but rotates the orientation of the tip (tool). For a further explanation of the tip rotational feature refer to co-pending application Ser. No. 11/302,654, filed on Dec. 14, 2005, particularly  FIGS. 25-28 , which is hereby incorporated by reference in its entirety. 
         [0061]    The handle  12 , via proximal bendable member  18 , may be tilted at an angle to the instrument shaft longitudinal center axis. This tilting, deflecting or bending is in three dimensions. By means of the cabling this action causes a corresponding bend at the distal bendable member  20  to a position wherein the tip is directed along an axis and at a corresponding angle to the instrument shaft longitudinal center axis. The bending at the proximal bendable member  18  is controlled by the surgeon from the handle  12  by manipulating the handle in essentially any direction including in and out of the plane of the paper in  FIG. 1 . This manipulation directly controls the bending at the proximal bendable member. For further descriptions relating to the bending and locking features refer to co-pending application Ser. No. 11/528,134 filed on Sep. 27, 2006 and Ser. No. 11/649,352 filed on Jan. 2, 2007, both of which are hereby incorporated by reference in their entirety. 
         [0062]    Thus, the control at the handle is used to bend the instrument at the proximal motion member to, in turn, control the positioning of the distal motion member and tool. The “position” of the tool is determined primarily by this bending or motion action and may be considered as the coordinate location at the distal end of the distal motion member. Actually, one may consider a coordinate axis at both the proximal and distal motion members as well as at the instrument tip. This positioning is in three dimensions. Of course, the instrument positioning is also controlled to a certain degree by the ability of the surgeon to pivot the instrument at the incision point or at the cannula or trocar. The “orientation” of the tool, on the other hand, relates to the rotational positioning of the tool, from the proximal rotation control member (knob  24 ), about the illustrated distal tip or tool axis P. 
         [0063]    In the drawings a set of jaws is depicted, however, other tools or devices may be readily adapted for use with the instrument of the present invention. These include, but are not limited to, cameras, detectors, optics, scope, fluid delivery devices, syringes, etc. The tool may include a variety of articulated tools such as: jaws, scissors, graspers, needle holders, micro dissectors, staple appliers, tackers, suction irrigation tools and clip appliers. In addition, the tool may include a non-articulated tool such as: a cutting blade, probe, irrigator, catheter or suction orifice. 
         [0064]    The surgical instrument of  FIG. 1  shows one embodiment of a surgical instrument  10  according to the invention in use and may be inserted through a cannula at an insertion site through a patient&#39;s skin. Many of the components shown herein, such as the instrument shaft  14 , end effector  16 , distal bending member  20 , and proximal bending member  18  may be similar to and interact in the same manner as the instrument components described in the co-pending U.S. application Ser. No. 11/185,911 filed on Jul. 20, 2005 and hereby incorporated by reference herein in its entirety. Some other components shown herein, particularly at the handle end of the instrument may be similar to components described in the co-pending U.S. application Ser. No. 11/528,134 filed on Sep. 27, 2006 and hereby incorporated by reference herein in its entirety. Also incorporated by reference in their entirety are U.S. application Ser. No. 10/822,081 filed on Apr. 12, 2004; U.S. application Ser. No. 11/242,642 filed on Oct. 3, 2005 and U.S. application Ser. No. 11/302,654 filed on Dec. 14, 2005, all commonly owned by the present assignee. 
         [0065]    As illustrated in, for example,  FIGS. 1-3 , the control between the proximal bendable member  18  and distal bendable member  20  is provided by means of the bend control cables  100 . In the illustrated embodiment four such control cables  100  may be provided in order to provide the desired all direction bending. However, in other embodiments of the present invention fewer or less numbers of bend control cables may be used. The bend control cables  100  extend through the instrument shaft  14  and through the proximal and distal bendable members. The bend control cables  100  may be constrained along substantially their entire length so as to facilitate both “pushing” and “pulling” action as discussed in further detail in the aforementioned co-pending application Ser. No. 11/649,352 filed on Jan. 2, 2007. The cables  100  are preferably constrained as they pass over the conical cable guide portion of the proximal bendable member, and through the proximal bendable member itself. 
         [0066]    The locking means interacts with the ball and socket arrangement to lock and unlock the positioning of the cables which in turn control the angle of the proximal bending member and thus the angle of the distal bendable member and end effector. This lock control allows the surgeon one less degree of freedom to concentrate on when performing certain tasks. By locking the bendable sections at a particular position, this enables the surgeon to be more hands-free for controlling other degrees of freedom of the instrument such as manipulation of the rotation knob  24  and, in turn, orientation of the end effector. 
         [0067]    The instrument shown in  FIG. 1  is considered as of a pistol grip type. However, the principles of the present invention may also apply to other forms of handles such as a straight in-line handle. In  FIG. 1  there is shown a jaw clamping or actuation means  30  that is comprised mainly of the lever  22  which may have a single finger hole in a gimbaled ball  27 . The ball  27  is mounted at the free end of the lever  22 . The surgeon uses the ball  27  for controlling the lever  22 . In an alternate embodiment, the ball  27  is optional and in its place is a simple through or blind hole at the free end of the lever  22 . There may also be provided a related release function controlled either directly by the lever  22  or a separate release button. The release function is used to release the tip of the instrument for interchange. 
         [0068]    In the instrument that is illustrated the handle end of the instrument may be tipped or deflected in any direction as the proximal bendable member is constructed and arranged to preferably enable full 360 degree bending. This movement of the handle relative to the instrument shaft bends the instrument at the proximal bendable member  18 . This action, in turn, via the bend control cables  100 , bends the distal bendable member in the same direction. As mentioned before, opposite direction bending can be used by rotating or twisting the control cables through 180 degrees from one end to the other end thereof. 
         [0069]    In the main embodiment described herein, the handle  12  is in the form of a pistol grip and includes a horn  13  to facilitate a comfortable interface between the action of the surgeon&#39;s hand and the instrument. The tool actuation lever  22  is shown in  FIG. 1  pivotally attached at the base of the handle. The lever  22  actuates a linkage mechanism (see  FIGS. 2 and 3 ) that controls the tool actuation cable  38 . The cable  38  controls the opening and closing of the jaws, and different positions of the lever control the force applied at the jaws. 
         [0070]    The instrument  10  has a handle portion  12  and a detachable shaft portion  14 , as shown in  FIG. 1 . Many of the components of the instrument may be like that shown in Ser. No. 11/649,352 filed on Jan. 2, 2007, particularly as to the construction of the bendable members, instrument shaft, end effector, rotation member and locking mechanism. This includes means for enabling rotation of the shaft and proximal bendable member within bearings or bearing surfaces  208  and  210  ( FIG. 3 ). The bearing  208  interfaces between the adaptor  26  and the ball  120 , while the bearing surface  210  is between the neck portion  206  and the instrument shaft. The separate portions  12  and  14 , or alternatively the assembled instrument, may be sealed in a sterile package or packages prior to storage or shipping. 
         [0071]    Reference is also now made to co-pending application Ser. No. 11/900,417 filed on Sep. 11, 2007 (which is hereby incorporated by reference in its entirety) for a description of a related instrument structure that includes a releasable shaft. The present invention is directed to further features particularly relating to the locking means for the shaft and for the cable lug. The locking means for the cable is actuation lever driven, and includes a spring loaded compensation means or member  152  (see  FIG. 5 ) for constant jaw pressure applied to different thicknesses of tools or tissue, as well as a ratcheting means  154  to maintain the applied pressure. The members  152  and  154  are discussed in further detail hereinafter. 
         [0072]      FIG. 2  shows the instrument in its rest position with the distal part of the instrument including the instrument shaft  14  engaged with the proximal part of the instrument including the control handle  12 .  FIG. 3 , on the other hand shows, shows the instrument in a used position in which the lever  22  is at least partially depressed (moved toward the handle in the direction of the arrow  22 A). In both of these views the distal part of the instrument is engaged with the proximal part of the instrument and the actuation cable is considered as interlocked or engaged so that operation of the lever  22  controls the movement of the actuation cable and in turn the actuation of the end effector  16 .  FIG. 4  is an exploded fragmentary cross-sectional view that depicts the distal part of the instrument (instrument shaft portion) having been removed from the control handle (instrument handle portion). 
         [0073]    As shown in  FIGS. 4 and 8 , the shaft portion  14  can be easily separated from the handle portion  12  by releasing the cinch ring  200 . For further details of the shaft portion release refer to co-pending application Ser. No. 11.900,417 filed on Sep. 11, 2007. The shaft portion  14  includes a shaft connector  212  (see  FIG. 4 ). The shaft portion  14  is captured at the proximal flange  210  in the shaft receiver portion  34  of the rotation knob  24 . Clamping blocks  182  capture the proximal flange  210 . The shaft connector  212  is locked linearly but the shaft locking means or member  150  allows rotation of the shaft portion relative to the handle portion. The cable lug  40  is captured by means of the engagement thereof with the cable engagement means  84 . 
         [0074]    The instrument includes an angle locking means  140  as shown in  FIGS. 1-4 . This angle locking means includes a split hub  202  which is constructed and arranged to allow the ball  120 , and the entire distal shaft portion, to be pulled out of the split hub  202 . The cinch ring  200  is used to lock and unlock the split hub  202 , as described in more detail later, and as further described in co-pending application Ser. No. 11/900,417 filed on Sep. 11, 2007. 
         [0075]    The split hub  202  includes portions or petals that each preferably have a tapered face so as to function as a ramp to force the petals apart when the ball  120  is pushed proximally against them during an insertion of the shaft portion into the handle portion. These inward faces or edges of the portions are beveled or tapered to allow easier passage of the ball. The split hub  202  is supported from the handle by means of struts  230  which are thinned so as to function as flexible living hinges to thus allow more ready expansion of the hub petals. This structure assists in the engagement and disengagement between the shaft portion and handle portion. 
         [0076]    The cinch ring  200  may have two flanges that ride in respective circumferential grooves that are disposed on the outer surface of the split hub  202 . This interface captures the cinch ring while allowing the split hub to be separated linearly. The cinch ring  200  is basically controlled from the angle locking member or means  140 . The angle locking member  140  is pivotally attached with the cinch ring  200 . The angle locking member  140  is comprised primarily of the release/lock lever  220  which controls the length or outer circumference of the cinch ring  200 . The angle locking member  140  is constructed and arranged to allow the cinch ring  200  to, not only be loosened enough to adjust the angle of the shaft relative to the handle, but to also expand to a size that is sufficient to allow enough expansion of the split hub portions to thus allow the ball  120  (and the entire distal shaft portion) to be removed or inserted in the split hub  202 . This enables the shaft portion to be readily dis-engaged from the handle portion. For other details of the cinch ring construction refer to co-pending application Ser. Nos. 11/649,352 filed on Jan. 2, 2007 and Ser. No. 11/900,417 filed on Sep. 11, 2007. 
         [0077]    The cinch ring  200  is operated by means of the over-center locking lever  220  that is connected to ends of the cinch ring  200  by means of the respective pins. The cinch ring  200  is free to rotate around the split hub  202  when lever  220  is released. This allows for left or right handed operation of the instrument. When the locking lever  220  is moved to its locked position this compresses the cinch ring  200  closing the hub against the spherical outer surface  204  of the ball member  120 . This locks the handle against the ball member  120  holding the ball member in whatever position it is in when the locking occurs. By holding the ball member in a fixed position this, likewise, holds the proximal bendable member in a particular position and fixed in that position. This, in turn, maintains the distal bendable member and tool at a fixed position, but the instrument orientation can be controlled via the control of the rotation knob which controls the orientation of the instrument tip by enabling rotation of the distal bendable member and tool about the tip axis P (see  FIG. 3 ). 
         [0078]    Another feature of the instrument shown in the first embodiment is the use of a separate shaft release lever  160  shown in  FIGS. 2 and 3 . The lever  160  operates a linkage mechanism that, in turn, controls the shaft locking member  150 . A sleeve  176  is controlled from the linkage mechanism and controls the opening and closing of clamping blocks  182 . These blocks  182  capture the post  214  and the entire shaft portion. In an alternate embodiment the clamping blocks may capture the cable in a different way such as by having a projection on each block engage a slot or hole in the cable. 
         [0079]    The instrument of the present invention provides the ability to re-use the handle portion of the instrument while the distal portion or shaft portion is disposable or resposable. This is enabled by providing a disconnection essentially at the proximal bendable member. As shown, for example, in  FIG. 4  the shaft portion  14  includes a shaft connector  212  attached to the proximal bendable member  18 . It is the shaft connector  212  that is engageable with or releasable from the receiver portion  34  of the rotation knob  24 . The shaft connector  212  may be seated in the receiver portion  34  of the rotation knob and is keyed to the rotation knob  24  by means of splines  238  of the connector  212  and grooves  240  in the seat  246  of the receiver portion  34 . Refer also to  FIGS. 8 and 9  for further details. A reduced diameter portion  242  of the shaft connector  212  passes through a clearance hole  244  in the seat  246  of the receiver portion  34  and abuts the clamping blocks  182  (see  FIG. 6 ) which when closed, loosely fit about a post  214  extending proximally through the semicircular bores  184 . The proximal flange  210  at the end of the post  214  is relatively loosely captured by the clamping blocks allowing rotational but not axial movement of the shaft connector  212 . Refer to  FIGS. 7 and 9 . 
         [0080]    The proximal end of the push/pull cable  38  is bonded to a tube  39  that is free to slide in bore  41  of the post  214 , as depicted in  FIG. 5 . The tube  39  maybe attached to the cable  38  in any one of a number of different ways such as by using an adhesive, soldering or crimping. The tube  39  is not illustrated as biased in any particular direction (proximally or distally), but may be spring-loaded proximally or distally to bias the jaws (or other end effector) into a desired “at rest” position. For example, a spring may be provided in the bore  41 , as in  FIG. 5 . The tube  39  has a lug  40  that is adapted to be captured by the cable engagement means  84 . The cable engagement member  84  is comprised primarily of the gate  260 . The gate  260  at the handle portion is controlled from the actuation lever  22 . The lug  40  has a taper  42  to aid in inserting the shaft into the handle and to provide clearance for the gate  260 . The gate  260  grabs the lug  40  as the lever  22  is initially squeezed and the carriage  82  is pulled proximally as best seen in  FIG. 5A  where the gate  260  has its slot  271  engage the lug  40 . The gate  260  moves up and down in a guide slot  262  in the carriage  82 . The gate is biased to a closed position as best seen in  FIG. 11  by a spring  264 . The spring is retained by an arm  266  that is screwed down to the top of carriage  82 . The lower end of the spring seats in a well  268  in the gate. When the gate is in the closed position the two semi-circular flanges  270  with a gap  271  between them extend into the central bore  272  in the carriage  82  to capture the cable lug  40  in the gap between the flanges. 
         [0081]    As shown in  FIG. 11 , the bore  272  has a taper  274  at its distal end to guide the lug  40  into position when inserting the shaft into the handle. The gate  260  bottoms out at  276  which corresponds to the end of the guide slot  262  to allow a radial clearance between the flanges  270  and the tube  39  to allow free rotation of the lug and tube within the carriage  82 . A ramp  278  on the gate  260  interacts with cam block  86  at the distal end of carriage travel to urge the gate open for release of the lug  40  when the lever  22  is at rest. This means that the cable lug  40  is normally free for shaft removal whenever the lever  22  is released or at rest, such as at the position shown in  FIG. 4 . 
         [0082]    When the lever  22  is squeezed the carriage  82  is pulled proximally in the direction of arrow  279  (See  FIGS. 3 ,  5 A,  6  and  11 ), the ramp  278  slides down the cam block  86  and the proximal flange  270  passes over the tapered edge  42  of the lug  40  while the distal flange  270  contacts the distal face of the lug  40 . This action initiates the pulling of the lug  40  in direction  279 . When the stroke reaches approximately the position of  FIG. 11 , the ramp  278  drops off the cam block  86  and the cable lug  40  is fully captured. The further squeezing of the lever  22  toward the handle results in the operation of the ratcheting means  154 . The lever  22  can then be fully squeezed to release the ratcheting member  154  and the cable engagement means  84 . This action returns the carriage  82  under bias from the spring  71  until the taper  274  of the carriage nests on the taper  216  of the flange  210  which aligns the engagement means  84  with the lug  40 . 
         [0083]    The compensation means  152  as best seen in  FIGS. 5 and 6  is now described. The compensation member  152  provides a bias force while at the same time accommodating different size needles or other objects at the end effector. For simplicity, the compensation means is not shown in  FIGS. 1-4 . The compensation means or member is comprised primarily of a link  79  that is constructed of two relative sliding portions  79   a  and  79 B. The link  79  is supported in a guide  290  on portion  79 A allowing portion  79 A to be biased proximally toward portion  79 A by means of the spring  292 . A shoulder  294  on portion  79 B acts as a stop. As shown in  FIGS. 2 and 3 , one end of the link  79  is supported from crank  76  at pin  80  while the opposite end is supported from carriage  82  at pin  81 . Crank  76  pivots at pin  78 . Link  74  is attached to crank  76  at pin  77 , and intermediate pins  77  and  78 . Pin  80  supports link  79  from crank  76 . When the lever  22  is squeezed the jaws  44 ,  46  of the end effector  16  close on needle  45 . After contacting the needle the link portion  79 A stops movement and portion  79 B continues to be pulled in a proximal direction under tension from spring  292  thus compensating for needle thickness while exerting a constant grabbing force to the jaws. 
         [0084]    The ratchet mechanism  154  is comprised of a spring loaded pawl  156  acting in a one way ratcheting action on rack  158 . The rack  158  is secured to an inner surface of the handle. In  FIGS. 2 and 5  it is noted that the pawl  156  is not yet engaged with the rack  158 .  FIG. 3  illustrates the lever substantially depressed with the pawl  156  near the end of its travel. The pawl moves along the rack until it clears the rack which would be just past the position shown in  FIG. 6 . The pawl  156  is then free to pivot past the teeth of the rack  158  and thus release the crank  76  to be returned to the start position of  FIG. 5  by lever return spring  71 . Once the pawl passes the end of its travel it automatically returns to the position of  FIG. 5  under control of the return spring  71 . This action also opens the gate  260  enabling release of the more distal shaft portion. 
       Shaft Portion Release 
       [0085]    The cinch ring  200  is released so the ball  120  of the shaft portion  14  can be pulled from the split hub  202 . The cinch ring is released by means of operation of the lever  220 . The shaft locking means or member  150  is released by pushing the lever  160  at the base of the handle in the direction of arrow  161  as shown in  FIG. 3  resulting in the pivoting of lever  160  in a clockwise direction about the pivot post  162 . This action is transmitted through linkage  164  which is connected at one end to lever  160  by means of pin  166 , and at the opposite end to the bell crank  168  which is connected to link  164  by pin  169  (see  FIG. 5 ). When the lever  160  is actuated the bellcrank  168  pivots counterclockwise about pin  170  and the slot  171  in the bellcrank drives pin  172  and, in turn, brackets  174  in the distal direction of arrow  163  as shown in  FIGS. 4 ,  5 ,  7  and  9 . The brackets  174  (see also  FIG. 10 ) are mounted to the rectangular sleeve  176  by screws or rivets  175 . The sleeve  176  has ramped slots  178  (see  FIGS. 9 and 10 ) that act against pins  180  mounted in clamping blocks  182 . This action urges the blocks  182  apart (open) in the direction of arrows  165  as illustrated in  FIGS. 7 and 9 . The clamping blocks  182  are prevented from lateral movement by guide pins  186  which ride in bores  188  in the blocks. The guide pins  186  are supported on arms  90  (see  FIGS. 5 and 6 ) which are fastened to the support tube  94  in a fixed position by means of locating pins  91  and screws  92 . The guide pins  186  pass through slots  190  in sleeve  176 , as illustrated in  FIG. 11 . 
         [0086]    The top arm  90  also supports post  88  on which cam block  86  is mounted. The post  86  also passes through the slot  190  in the sleeve  176 . The opening of the clamping blocks  182  leaves a clearance for the proximal flange  210  of the shaft connector  212  to be withdrawn through the passage created by the semi-circular bores  184  in the blocks ( FIGS. 7 and 9 ). The shaft connector  212  can then be removed from the shaft receiver portion  34  of rotation knob  24  and, at the same time, the ball portion  120  of the shaft is pulled out of the split hub  202 , as illustrated in FIGS.  4  and  7 - 9 . 
       Shaft Portion Insertion 
       [0087]    The following description relates to the insertion sequence of the shaft portion  14 . As the shaft portion is inserted, the ball  120  passes through the distal edge of split hub  202 . This distal edge may be tapered as shown in  FIG. 4  to assist in the insertion and to provide some guidance. The shaft connector  212  is guided into position at least by way of the taper  36  on the shaft receiver portion  34  and also by means of the tapers  239  on the splines  238  of the shaft connector  212 .  FIGS. 6 and 8  also show how the taper  216  of the proximal flange  210  assists in the insertion by engagement with the taper  274 . Moreover, the clamping blocks  182  are each provided with a taper  183  to assist in alignment of the shaft portion  14 , and as illustrated in  FIG. 9 . These various tapers assist in centering of the cable lug  40  as it passes into the carriage  82 , such as depicted in  FIG. 7 . 
         [0088]    When the ends of the splines  238  contact the seat  246  (see  FIG. 9 ), the shaft portion  14  can then be rotated until the splines  238  align with the grooves  240 . The shaft connector  212  can be inserted all the way into receiver portion  34  until the seat  246  prevents further proximal movement by contacting the shoulder  248  of the connector  212 . The shoulder  250  of shaft connector  212  simultaneously contacts the face  252  of the clamping blocks  182 . The shaft release lever  160  may then be pulled proximally (in a direction opposite to that of arrow  161  in  FIG. 3 ) resulting in the proximal movement of sleeve  176  in the direction of arrow  167  in  FIG. 10  which, in turn, closes the clamping blocks  182  about the post  214 , capturing the annular flange  210 . The arrows  173  shown in  FIGS. 10 and 11  illustrate this closure and the capture of the flange  210 . The release lever  160  may be provided with detents so as to keep it in either of the clamped or released positions, so that the shaft portion would not be mistakenly released. Once the shaft portion  14  is captured in the handle portion  12 , then the lever  22  is used to control the actuation of the end effector. For example, FIG.  3  shows the lever at least partially depressed with the carriage  82  moved proximally and with the jaws  44 ,  46  closed for grasping a needle  45 . 
       Cautery Tool Embodiment 
       [0089]    An alternate embodiment of the present invention is shown in  FIG. 12  in which the instrument  310  is particularly adapted for cauterization performed in surgery. Further details are illustrated in  FIGS. 13-17 . This embodiment also provides for a replaceable shaft with a different release mechanism, as described hereinafter. In the previous embodiment described herein a set of jaws are depicted. In this embodiment the end effector has been replaced with a collet mechanism  316  that releasably grasps a cautery tool  320  and provides an electrical connection to the electrical contact  322  (see  FIG. 12B ) of the tool for enabling selective activation of the cautery tool. The cable  38  is used to clamp the collet  316  as well as provide an electrical current to heat the cautery tool. The cable is divided into two portions, one portion  38 A is integral with the shaft  314  and is electrically insulated by a sheath  315  (see  FIG. 12B ) which also is preferably constructed of a low friction material to allow the cable to readily slide within the sheath  315 . The cable portion  38 B also has an insulating sheath  317  (see  FIG. 13 ). The cable portion  38 B passes through the sheath  317  and is connected at its more proximal end to a slider  28  at barrel  66 . 
         [0090]    The internal portion of the handle is not shown in detail herein but earlier applications that have been incorporated by reference herein disclose more details of the slider and barrel arrangement that may be used for actuating the cable  38 . Refer, for example, to application Ser. No. 11/185,911 filed on Jul. 20, 2005; Ser. No. 11/302,654, filed on Dec. 14, 2005; Ser. No. 11/505,003 filed on Aug. 16, 2006; Ser. No. 11/528,134 filed on Sep. 27, 2006 and Ser. No. 11/649,352 filed on Jan. 2, 2007. In an alternate embodiment the barrel  66  may not be needed and the cable may be clamped directly to the slider since the cable  38 A is free to rotate independently at the connector  384 . The proximal end of the cable  38 B then passes into a handle extension  324  that is attached to the end of the handle  12 . The handle extension  324  contains a tubular electrical contact  326  that allows the cable to slide proximally and distally while maintaining electrical connection to a variable voltage source  328  that is, in turn, connected to the contact  326  at node  330  by means of the flexible cable  332 . A switch (not shown) may be supported conveniently at or adjacent to the extension or variable voltage source so that the voltage can be selectively applied to the tool  320 . 
         [0091]    The collet mechanism  316  is illustrated in  FIGS. 12A and 12B  and is used to accept different sizes, shapes, styles, etc. of tools  320 . Depending upon the particular surgical procedure, the tool is typically provided in bent configurations. In accordance with the present invention, rather than having to use different overall instruments corresponding to each type, a single instrument can be used and the different tool tips are simply replaced at the tip of the instrument in order to change tool types, sizes or shapes. The collet  360  is made of electrically insulating material such as a hard plastic and is attached to the distal end of the distal bendable member  20  and cables  100 . Jaws  364  are activated to grasp and release the tool  320 . In the disclosed embodiment four such jaws are used, however, it is understood that different numbers of jaws maybe employed. The base  362  of the jaws  364  contain an electrical contact  366  that may be soldered onto the distal end of cable  38 A. The contact  366  mates with the contact  322  on the cautery tool. The base  362  may be constructed of metal material and it may be soldered at  368 , as illustrated in  FIG. 12B , to provide further electrical contact between cable  38 A and the contact  322  of the cautery tool. 
         [0092]    The cautery tool is adapted for grasping and release by the collet and jaw structure shown in  FIGS. 12A and 12B . This grasping or release is controlled from the actuation cable  38 . Because the cautery tool is an non-articulating tool the main cable is not needed for tool actuation and is instead used for the selective capture of the cautery tool itself. The cautery tool  320  is pushed into the relaxed jaws until contact  322  of the tool bottoms out against contact  366  in the base  362 . The lever  22  may then be squeezed (depressed inwardly toward the handle) thus causing the cable  38 A to pull the jaws  364  into the collet  360 . This relative motion between the jaws and collet essentially closes the jaws against the tool. This is illustrated in  FIG. 12B  by the direction of arrows  369 . The cautery tool is thus secured in the collet  360  and is electrically connected to the voltage source  328 . The electrically energized jaws  364  and contact  322  are recessed from the distal end of the insulated collet  360  in order to prevent shock to the patient. The lever  22  may be provided with one or more detents so that the lever can be maintained in the particular desired position, either locked or released. 
         [0093]    This embodiment of the invention also discloses an alternate way of engaging the shaft portion of the instrument. An alternate cable engagement means or member  284  is shown in  FIGS. 13-17 . This embodiment also is illustrated with a proximal bendable member  18  that has ribs defining adjacent slots as in previous instruments shown in applications incorporated herein. Many of the components in this embodiment may be the same as shown in the first embodiment herein such as the shaft connector  212 , the ball  120 , the rotation knob  24  and the proximal flange  210 . Mainly, the alternate cable engagement member  384  is discussed in further detail herein. In the first embodiment described herein the capture of the shaft portion involved action at the release lever  160  that was located at the very proximal end of the handle. In this second embodiment separate members are used including the cable release button  388  and the release lever  430 . The button  388  is for engaging the contact between the cable sections while the lever  430  is used to lock the shaft portion  314  in place relative to the handle. 
         [0094]    A slidable sleeve  386  is supported in the handle support tube  394  as shown in  FIGS. 13 and 15 . The sleeve  386  functions as a collet controlling the grasping fingers  392 , and is connected to and operated from the release button  388 . The sleeve  386  is slidable proximally and distally in the support tube  394  which is formed as part of the handle. The taper  387  at the distal end of the sleeve  386  (see also  FIGS. 16 and 17 ) opens or closes fingers  392  about the lug  340 . The sleeve  386  functions as a slideway for the connector  390  when the cable  38 B is pulled or released by lever  22  in the process of engaging or releasing the cautery tool. The fingers  392  may be made of a metal material for electrical conduction purposes with the lug  340 . The base  393  of the fingers  392  may be soldered, as illustrated at  395  in  FIG. 13 , to a metal core  396  that, in turn, is soldered at  397  to the bare end of the cable  38 B. An electrical contact in the form of a spring  398  may be attached to the core  396  to ensure good electrical contact with the metal lug  340  which may be soldered to the cable  38 A or attached in any other suitable manner. A plastic insert  400 , with slots  402  for accommodating the fingers  392 , includes a seat  404  (see  FIG. 17 ) for engaging the taper  342  on the lug  340 . 
         [0095]    The insert  400  also has a taper  406  (see  FIG. 17 ) at the distal end to aid in alignment of the lug  340  with the connector  390  when inserting the shaft into the instrument. As can be seen in  FIG. 16 , the cable lug  340  is free to rotate within the connector  390  but maintains electrical contact with cable  38 B. The release button  388  is attached to the sleeve  386  by means of a narrow neck  408  (FIG.  15 ) that protrudes through a slot  410  in the handle. The release button  388  slides in and out of a recess  412  in the top of the handle just behind the horn  13 . The button  388  has a nub  413  that snaps into detents  414  in the recess  412  in both locked and unlocked positions. When the button  388  is pulled in the direction  389  depicted in  FIG. 15 , that action pulls the sleeve  386  back from the fingers  392 , letting the fingers spread open for clearance for the lug  340  to be removed or inserted. When it is in this outer or extended position the button  388  protrudes noticeably above the surface of the handle, as shown in solid outline in  FIG. 15 , as a clear indicator that the cable is not locked in place. If the button  388  is moved distally that action slides the sleeve  386  against the connector  390  and thus locks the cable at the fingers  392 , as is depicted in solid outline in  FIG. 13 . 
         [0096]    An alternate embodiment of shaft locking means is illustrated at  350 , and is now described as shown in  FIGS. 12-15 . Instead of clamping blocks closing around the neck  214  as in the first embodiment described herein, a gate  420  with a semi-circular rim  422  (see  FIG. 14 ) captures the flange  210  on the shaft connector  212 . The gate  420  rides in a guide slot  424  formed in the support tube  394 . A stop  426  (see  FIG. 15 ) at the bottom of the slot keeps the rim  422  from contacting the post  214 . A boss  428  on the top of the gate  420  is connected to release lever  430  by means of the pin  432 . The lever  430  sits in a slot  434  on the underside of the horn  13  and pivots on pin  436 . A nub  438  on the lever  430  snaps into detents  440  on the side of the slot  434  in both unlocked and locked positions. The lever  430  may be accessed by inserting a thumbnail at the top of the slot and pushing down. When the lever is in the unlocked position as shown in phantom line in  FIG. 13  and in solid line in  FIG. 15 , it is a noticeable indicator that the shaft is not locked in place. The instrument is ready for use when both the button  388  and lever  430  are in their recessed positions. 
       Rotary Cutting Tool Embodiment 
       [0097]    An alternate embodiment of the surgical instrument for use as a rotary cutting tool is shown in  FIG. 18 . Additional details are found in  FIGS. 18A ,  18 B,  18 C,  19  and  20 . The end effector  516  has a collet clamping mechanism  516  that holds a tool such as a rotary cutter  520  in this particular embodiment. It is understood that other forms of rotary tools may also be used, as well as other forms of stationary tools. The collet clamping mechanism  516  allows the collet  560  and cable portion  38 A to rotate freely. The cable portion  38 A passes through a low friction sheath  515  (see FIG.  18 B) in the main instrument shaft and connects to cable portion  38 B by means of the cable engagement means or member  584 . The mechanism  584  keys the two cable portions together rotationally as well as laterally. The cable portion  38 B then passes through a low friction sheath  517  (see  FIG. 18 ) in stiffening tube  64  to the slider  28  where the stiffener tube and sheath end just short of the barrel  66 . The exposed cable is then clamped to barrel  66 . Barrel  66  is made of a low friction material in order to be able to rotate freely within the slider  28  when the cable  38 B is driven by motor  526 . The cable  38 B then passes through another short section of sheath (not shown), through the end of the handle to a splined chuck  522  on motor shaft  524  of the motor  526 . The cable is connected to the chuck  522 . The splined chuck  522  allows limited lateral motion of the cable while transferring rotational force from the motor which can be battery driven or externally connected to a power source and controlled by a switch  528 . The motor  526 , switch  528  and batteries and/or external power connector are contained in housing extension  530 . 
         [0098]    The collet mechanism  516 , shown in  FIGS. 18A-18C , is now described. This mechanism is for locking and/or releasing the tool at the distal tip of the instrument. For this purpose a collet  560  is supported in bearings  562  within the outer housing  564  which, in turn, is connected to the distal bendable member  20  and the cables  100 , as shown in  FIG. 18B . Four jaws  566  clamp the tool  520  when the cable  38 A, which is secured to the base  568  of the jaws by square lug  570 , is pulled by squeezing the lever  22 . This action pulls the tool into the collet holding the tool securely. The lever  22  may be provided with one or more detents so that the lever can be maintained in the particular desired position, either locked or released. The tool  520  which is shown as a rasp can then be rotated at high speed by the motor  526 . 
         [0099]      FIGS. 18-20  show the cable locking means or member  584  which is similar to the cable locking means  384  but modified to transmit rotational force from cable portion  38 A to cable portion  38 B instead of an electrical current. The connector  590  is supported and operated by a slidable sleeve  586  and taper  587  similar to the sleeve  386  and taper  387  as shown in the previous embodiment of  FIGS. 12-17 . Fingers  592  are supported from the base  593 . These fingers  592  have slightly raised rims  594  and  595  that act as bearing surfaces against the sleeve  586 . They are mainly used to reduce rotational friction as the connector spins inside the sleeve when the motor is running. They may be made of metal or plastic since they do not have to pass a current through them. 
         [0100]    The fingers and base are mounted on a core  596  of metal or plastic that is secured to the end of cable portion  38 B. The core  596  has slots  602  for the respective fingers  592  that allow the fingers to pass through and grab the lug piece  540 . The core  596  has a seat  604  for receiving the lug piece  540  and a taper  606  to aid in guiding the lug upon insertion. The core has open ended slots  608  with tapers  610 . The slots and tapers guide and capture the four lugs  544  with their tapers  546  that are on the circumference of each of the cable lug  544 .  FIG. 19  shows the fug member  540  captured with each of the lugs  544  in a corresponding slot  608  and with the fingers  592  compressed capturing the lug member  540 . The rims  594  form a bearing means against the inner surface of the sleeve  586 .  FIG. 20 , on the other hand, shows the mechanism  584  released with the fingers  592  spread and the fug member  540  out of engagement with the fingers. The mechanism  584  is partially extending out of the sleeve  586 . 
         [0101]    Having now described a limited number of embodiments relating to the principles of the present invention, it should now be apparent to one skilled in the art that numerous other embodiments and modifications thereof are contemplated as falling within the scope of the present invention, as defined by the appended claims. For example, in the first embodiment disclosed herein the cable is engaged by means of the engagement between the cable lug  40  and gate  260 . In an alternate embodiment instead of a lug, a recess can be provided in the cable and instead of the slot or gap in the gate, a projection can be used for engaging with the recess. Also, the respective linkage and slider mechanisms can be interchanged between the various embodiments that are described herein.