Abstract:
A surgical instrument for use in laparoscopy is provided, comprising a tubular member having a proximal end and a distal end, a first end effector piece pivotably mounted to the tubular member near the distal end of the tubular member, a second end effector piece disposed near the distal end of the tubular member and being slidable relative to the tubular member, wherein a surgical item, such as a suture needle, may be received between the first end effector piece and the second end effector piece and may be rolled substantially axially by axial translation of the second end effector piece with respect to the first end effector piece. In one embodiment, the end effector pieces may be provided with depressions in their face surfaces. In another embodiment, the surgical instrument may also include a handle assembly having a control lever and a rotation actuator. The tubular member may also be rotatably mounted on the handle. In another embodiment, the handle assembly may comprise a number of servomotors for effecting motion in the tubular barrel and the end effector pieces.

Description:
RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Application Ser. No. 60/105,594, filed Oct. 26, 1998. 
    
    
     The present invention relates generally to the field of surgical instruments. In particular, it relates to an end effector of a surgical instrument for use in endoscopic surgical procedures. 
     BACKGROUND OF THE INVENTION 
     Endoscopy is a minimally invasive surgical procedure and includes, among other procedures, laparoscopy, thoracoscopy, and arthroscopy. Endoscopic procedures involve viewing the interior of the body using an illuminated optical instrument, referred to as an endoscope. The endoscope and other surgical instruments for operating on tissue inside the body enter the body through ports placed in small incisions in the skin. 
     Endoscopic procedures are typically conducted using specialized surgical instruments that have been adapted to perform general surgical procedures endoscopically. Endoscopic surgical instrument end effectors often take the form of a scissors, dissectors, or scissoring jaws, attached to the distal end of a rigid shaft. A handle attached to the proximal end of the shaft has a mechanism for operating the end effector. An operating linkage inside the shaft connects the handle to the end effector. The handle may also have a second mechanism for rotating the shaft and end effector. 
     Suturing is the preferred method of tissue approximation in endoscopic procedures. Suture needles are typically curvilinear in shape to facilitate stitching. One end of a suture needle is sharpened, and suture thread is attached to the other end of the needle. Because of restrictions on space and on instrument orientation, suture placement and tying of the suture thread involve difficult and awkward movements, making the process of suturing both lengthy and tedious. Surgical needle holders and needle drivers designed for endoscopic procedures generally have taken the form of an elongated tool designed to hold the suture needle rigidly and immovably in the surgical instrument. These holders and drivers enable the surgeon to hold and push the needle through tissue, but do not give the surgeon good needle mobility. 
     While the holders or drivers are typically comprised of a pair of jaws, they can take other forms, such as a gripper and anvil. A needle is typically grasped by the jaws midway between the tip of the needle and its tail. When a needle is first grasped in the jaws of a traditional needle holder, the needle may curve in any direction, whether upward, downward, distally, or proximally. In practice, the surgeon uses a second instrument, such as a forceps, a dissector, or another needle holder, to grasp and help orient the needle before suturing. This practice can be awkward and slow, and can also result in errors. 
     As surgeons become more proficient in conducting minimally invasive surgery, they are attempting to conduct more difficult and complex procedures laparoscopically. These newer procedures often require accurate suture placement. Present laparoscopic needle holders hold the needle firmly, but do not allow the operator to reorient the needle easily. In open surgery, where access is not restricted, this is not a problem. However, where access becomes restricted, such as in endoscopic procedures, needle re-orientation by the needle holder becomes more important. 
     SUMMARY OF THE INVENTION 
     In general, an end effector in accordance with the present invention includes a needle roller attached to a handle portion of a surgical instrument by an elongated tubular barrel. A handle on the handle portion may provide for holding the instrument and may also provide natural and precise control for grasping, rotating, and rolling a needle. The tubular barrel may be rotatably connected to the handle, and the needle roller may be disposed at the distal end of the tubular barrel. The handle may be configured to give full independence between the actions of rolling the needle, gripping the needle, and rotating the needle about the axis of the tubular barrel. Two linkage members may be disposed along the inner length of the tubular barrel and connect the end effector pieces with controls in the handle. In one embodiment, the end effector is plier-like and includes two jaws. The first jaw is pivotably attached to a pin affixed to the distal end of the tubular barrel. The first jaw is also coupled to the distal end of the first linkage member so that axial motion of the first linkage member causes the jaw to pivot open or closed. 
     In operation, the needle is grasped between the two jaws by pivoting the first jaw toward the second jaw. The first jaw is pivoted by pulling the first linkage member in a proximal direction. The first linkage member is coupled, at its proximal end, to a control actuator, in the form of a thumb trigger lever, mounted on the handle. When the thumb trigger lever is squeezed toward the handle, the first linkage member slides proximally inside the tubular barrel and thereby closes the first jaw. A trigger lock may also be provided to lock the thumb trigger lever to the handle and thus allow the surgeon to grasp and lock the jaws onto a needle. 
     The second jaw is a sliding jaw and is attached to the distal end of the second linkage member. The second jaw slides axially along with the second linkage member. Such axial motion of the second jaw causes a needle held between the jaws to roll. The second linkage member may be moved by operating a fingerwheel, a fingerloop, or a fingertrigger, in the handle, to which the second linkage member may be operably connected. The fingerwheel, when rotated by the surgeon&#39;s index finger, or the fingerloop or fingertrigger, when pushed or pulled by the surgeon&#39;s index finger, thus translates the second jaw. 
     The handle assembly may also take the form of a servomotor-powered set of actuators. Servomotors may be coupled to the tubular barrel and to each of the linkage members. The servomotors may be mounted transversely to the longitudinal axis of the tubular barrel or may be mounted parallel to the rotational axis of the tubular barrel. 
     The jaw surfaces may be coated with a high friction or abrasive surface to better hold the needle. The coating serves both to permit the jaws to grip the outside of the needle to facilitate rolling of the needle, and also to hold the needle securely in place to permit the surgeon to push the needle without it sliding in the jaws. 
     Suturing may also be aided by axial rotation of both jaws, i.e., rotation about the longitudinal axis of the tubular barrel. The tubular barrel is rotatably attached to the handle but is restrained from moving axially. Rotation is accomplished by, for example, applying rotational force with the index finger to a rotation knob attached to the tubular barrel, or by operating a servomotor coupled to the tubular barrel. Because the first jaw pivots on a pin that is attached to the tubular barrel and the second jaw extends from the tubular barrel, both jaws rotate when the tubular barrel rotates. 
     The jaws may also be provided with opposing internal pockets on their faces. Flat jaws often cause excess stress on a curvilinear needle because they force the portion of the needle that is between the jaws to straighten. In a disclosed embodiment, small recesses, or pockets, are formed on the interior surfaces of the jaws. A needle is allowed to curve slightly into these pockets and therefore undergoes less overall stress than if there were no pockets. 
     A device in accordance with the present invention can be capable of positioning a needle within the limited space provided by an endoscopic procedure. The device may also provide a simple, robust mechanism for achieving the needle-rolling function. The device may be reusable utilizing standard sterilization means, such as steam, gas, or soaking. The device is simple, yet it may provide precise and intuitive one-handled controls for changing the direction of curve of a needle, for rotating the needle, and for rigidly grasping the needle. 
     In one embodiment, a surgical instrument used in laparoscopy is provided, comprising a tubular member having a proximal end and a distal end, a first end effector piece pivotably mounted to the tubular member near the distal end of the tubular member, and a second end effector piece disposed near the distal end of the tubular member and being slidable relative to the tubular member and the first end effector piece, wherein a surgical item may be received between the first end effector piece and the second end effector piece and may be rolled substantially axially by axial translation of the second end effector piece with respect to the first end effector piece. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a left-side elevational view of the surgical instrument on which the needle roller end effector is mounted. 
     FIG. 2 is a sectioned isometric view of the end effector jaws. 
     FIGS. 3A-3C are left-side elevation views of the end effector mechanism showing the grasping and rolling of a needle. 
     FIGS. 4A-4E are isometric views of the end effector mechanism showing the jaws grasping, rolling, rotating, and releasing a suture needle. 
     FIGS. 5A and 5B show a particular geometry of the end effector jaws. 
     FIG. 6 is a left-side elevational view, partly in cross-section, of a handle assembly that may be used to operate the end effector. 
     FIG. 7 is an isometric view of the handle assembly of FIG.  6 . 
     FIG. 8 is an isometric view of a fingerwheel and hub rack inside the handle shown in FIG.  6 . 
     FIG. 9A is a section view showing the top portion of the fingerwheel of FIG.  8 . 
     FIG. 9B is a top-end view of the fingerwheel of FIG.  8 . 
     FIG. 10A is a view of the top side of the hub rack of FIG.  8 . 
     FIG. 10B is a side view of the hub rack of FIG.  8 . 
     FIG. 11 is an elevational view showing an alternate handle assembly in accordance with the present invention. 
     FIG. 12 is an elevational view, partially in section, showing the internal mechanisms of the handle assembly of FIG.  11 . 
     FIG. 13 is an elevational showing another handle assembly. 
     FIG. 14 is an elevational view, partially in section, showing the internal mechanisms of the handle assembly of FIG.  13 . 
     FIG. 15 is an elevational view, partially in section, showing an alternative embodiment of the internal mechanisms of the handle assembly of FIG.  13 . 
     FIG. 16 is an isometric view of a motor-powered handle assembly. 
     FIG. 17 is a perspective view of the handle assembly shown in FIG. 16 with the external housing removed for clarity. 
     FIG. 18 is an isometric view of another motor-powered handle assembly. 
     FIG. 19 is a perspective view of the handle assembly shown in FIG. 18 with the external housing removed for clarity. 
     FIG. 20 shows a detachable end effector in accordance with the present invention. 
     FIG. 21A is a left-side section view of another embodiment of the end effector mechanism showing the pivoting of the jaw. 
     FIG. 21B is a left-side section view of the end effector shown in FIG. 21A, showing the rolling of a needle. 
     FIGS. 22A and 22B are left-side section views of another embodiment of the nd effector mechanism showing pivoting of the jaw. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a left-side elevational view of a surgical instrument in accordance with the present invention. As shown in FIG. 1, the surgical instrument has a handle assembly  2  having a handle body  6  on which a trigger lever  4  is mounted. A rotation actuator, in the form of a rotation knob  12  and a rolling actuator, in the form of a pivoting fingerwheel  8 , may also be provided on handle body  6 . Generally, handle body  6  is held by a surgeon in either hand with a thumb through trigger lever  4 , leaving the index finger to operate rotation knob  12  and fingerwheel  8 . A tubular barrel  10  extends forward from handle assembly  2 , with rotation knob  12  at its proximal end. The tubular barrel  10  also has disposed at its distal end an end effector  1  which consists of a pair of end effector pieces, shown in the figures as jaws  40 ,  44 . A pin  42  pivotally attaches jaw  40  to the distal end of tubular barrel  10 . 
     Handle assembly  2  may be configured to produce three separate motions in the end effector. First, rotation knob  12  may be turned to rotate tubular barrel  10  and thereby rotate end effector  1 , as shown by rotation arcs C 1  and C 2 . Second, trigger lever  4  may be squeezed toward handle assembly  2 , as indicated by rotation arc A 1 , to cause jaw  40  to conduct a “grasping” motion relative to jaw  44 , as indicated by rotation arc A 2 . Third, fingerwheel  8  may be rotated, as shown by rotation arc B 1 , to cause axial motion of jaw  44 , as shown by arrow B 2 , so that a suture needle held laterally between jaw  40  and jaw  44  is caused to roll axially. 
     FIG. 2 is an oblique view showing jaws  40 ,  44  holding a needle  54 . Tubular barrel  10  is generally immovable and functions as a base and housing for end effector  1 . clamping of needle  54  is accomplished through pivoting of jaw  40 . Jaw  40  is pivotably mounted in an opening at the distal end of tubular barrel  10  on pin  42 , which is positioned transverse to the longitudinal axis of tubular barrel  10 . Pin  42  is mounted at each end in the wall of tubular barrel  10 . Jaw  40  is connected by way of link  34  and link  31  to a linkage member, in the form of control rod  30 , which is located coaxially with, and inside of, tubular barrel  10 . Axial motion of control rod in the proximal direction, i.e., toward the handle assembly, draws link  31  and link  34  in the proximal direction, causing jaw  40  to pivot toward jaw  44 . Axial motion of control rod  30  in the distal direction pushes link  31  and link  34 , causing jaw  40  to pivot away from jaw  44 . 
     Rolling of needle  54  is accomplished through axial motion of jaw  44 . Jaw  44  extends from the distal end of tubular barrel  10  and is attached at its proximal end  45  to control tube  32 . In the pictured embodiment, control tube  32  is coaxial with, and external to, control rod  30 . In addition, control tube  32  is coaxial with, and internal to, tubular barrel  10 . Control tube  32  and control rod  30  could also be positioned side-by-side. Axial motion of control tube  32  in the proximal direction causes axial motion of jaw  44  in the proximal direction, and axial motion of control tube  32  in the distal direction causes axial motion of control tube  32  in the distal direction. The position of jaw  44  is independent of the degree of closure of jaw  40 . 
     In FIG. 3A, the end effector mechanism is shown with the tubular barrel removed. A box-like cutout  43  is shown in the bottom of jaw  44  and a slot  46  is shown in the sides of jaw  44 . Slot  46  allows free axial translation of jaw  44  relative to pivot pin  42 . Pivot pin  42  is fixed to tubular barrel  10  and is pivotably connected to jaw  40 . 
     FIGS. 3B and 3C show the end effector assembly in operation in side cross-section. In FIG. 3B, needle  54  is shown firmly grasped in jaws  40 ,  44  and pinched between jaw  40  and jaw  44 . Control rod  30  is shown pulled in the proximal direction so that jaw  40  clamps tightly against jaw  44 . In FIG. 3C, control tube  32  is shown sliding in the distal direction relative to control rod  30  and pin  42 . As jaw  44  is forced in the distal direction by control tube  32 , the relative “shearing” between the surface of jaw  40  and the surface of jaw  44  causes needle  54  to roll axially in the distal direction and also to rotate clockwise. During rolling, jaw  40  is held closed against jaw  44  by control rod  30  in order to maintain friction between the surfaces of jaws  40 ,  44  and the outside of needle  54 . 
     FIGS. 4A-4E show the various ways in which the end effector assembly may manipulate a needle. Tubular barrel  10 , which provides support for pin  42 , has been removed to better illustrate the components of the mechanism. FIG. 4A shows grasping of needle  54 . Control rod  30  is pulled in a proximal direction shown by arrow A 1 , and thereby causes jaw  40  to pivot toward jaw  44  about pin  42 , as shown by arrow A 2 . As jaw  44  pivots downward, it clamps down on needle  54 . 
     FIG. 4B shows rotation of needle  54  about the longitudinal axis of the tubular barrel (not shown). Rotation of tubular barrel  10  (not shown in FIG.  4 B), as shown by rotation arc C 1 , causes rotation of all the components of the end effector  10  mechanism, as shown by rotation arc C 2 . Rotation of needle  54  during grasping helps to produce a suturing motion. 
     FIG. 4C shows rolling of needle  54  with its axis perpendicular to the longitudinal axis of the tubular barrel (not shown). Control tube  32  is moved axially in the proximal direction, as shown by arrow B 1 , and thereby causes jaw  44  to slide in the proximal direction. Sliding of jaw  44  relative to jaw  40  with needle  54  clamped tightly between the jaws, causes rolling of needle  54  in the counter-clockwise direction as shown by rotation arc B 2  and causes needle  54  to roll along the surface of jaw  40  in the proximal direction. During sliding of jaw  44 , pin  42  slides freely inside slot  46 . 
     FIG. 4D shows rolling of needle  54  in a direction opposite of that shown in FIG.  4 C. Axial translation of control tube  32  in the distal direction causes axial translation of jaw  44  in the distal direction. Translation of jaw  44  relative to jaw  40  with needle  54  clamped tightly between jaws  40 ,  44  causes rotation of needle  54  in the clockwise direction, as shown by rotation arc B 2 , and causes needle  54  to move axially in the distal direction. 
     FIG. 4E shows release of needle  54 . Axial motion of control rod  30  in the distal direction, as shown by arrow A 1 , causes jaw  40  to pivot upward away from jaw  44 , as shown by arc A 2 . 
     FIGS. 5A and 5B illustrate configurations in jaw geometry to facilitate rolling of a curved needle. FIG. 5A shows a pocket  50  formed in the face of jaw  44 . A similar pocket  48  is formed in the surface of jaw  40 , as shown in the end sectional view of FIG.  5 B. Because only the edges of the jaw surfaces contact needle  54 , the grasping surfaces of jaw  40  and jaw  44  are reduced to pairs of line contact, resulting in smoother and easier needle roll from 0 degrees through 180 degrees. As a result, needle  54  is forced to distort less, and jaws  40 ,  44  are required to open less to accommodate the curvature of needle  54  as it passes through an angle roughly normal to jaws  40 ,  44 . 
     Smooth and consistent rolling of needle  54 , which is normally of a circular cross section or other geometric form with rounded corners, is aided by good contact between the needle surface and jaws  40 ,  44 . Higher friction results in more positive rolling action and a firmer grip for suturing. Several materials traditionally have been used to surface jaws  40 ,  44  to improve needle gripping. Tungsten-carbide pads with a fine diagonal hatch may be brazed to the jaws. Alternatively, the jaw surfaces can be plated with diamond grit to achieve similar performance. To function effectively, the jaws ordinarily should hold the needle immovably. For a tight hold, the jaws should have a hard surface coating, and also be made of a material which is tough, high-strength, and corrosion resistant. The sliding jaw  44 , in particular, is exposed to extremely high bending stresses when it is slid in the extreme distal position and then closed fully on a large needle. One exemplary material having such characteristics is a precipitation hardenable stainless alloy such as 17-4 PH or one of the 400-series alloys. 
     In general, the materials from which the other metallic parts of the present invention are formed are selected from appropriate materials such as stainless steel, and other high strength metallic alloys. The tubular barrel may be fabricated of stainless steel and the handle may also be fabricated of stainless steel, or molded of high strength engineering plastics or the like. Components and materials for this instrument may be selected from commercially available items, which those skilled in the art will be able to recognize and select as equivalent. 
     FIG. 6 shows a handle assembly  2  that may be used with an end effector  1  in accordance with the present invention. Other controllers that are capable of imparting motion to end effector  1 , eg., different handle designs or servo-motor mechanisms, could also be used. Generally, handle body  6  is held by either hand and with a thumb through trigger lever  4 , leaving the index finger free to operate and rotate fingerwheel  8  and rotation knob  12 . Trigger lever  4  may be moved toward handle body  6  to effect a grasping operation of end effector  1  by squeezing the thumb toward the other fingers. This squeezing motion causes trigger lever  4  to pivot about pin  52 , so that the top of trigger lever  4  moves backward away from the rest of handle body  6 . 
     Transverse pin  22  pivotably attaches cylinder  16  to thumb lever  4  so that cylinder  16  moves proximally when thumb lever  4  is squeezed. Control rod  30  has an enlarged head disposed inside cylinder  16  so that proximal motion of cylinder  16  is transferred to control rod  30 . Motion of thumb lever  4  thereby results in motion of jaw  40  by way of transverse pin  22 , cylinder  16 , and control rod  30 . Motion of thumb lever  4  toward handle  6  (i.e., squeezing motion) causes jaw  40  to clamp down against jaw  44  (see FIG.  2 ). Spring  18  is located inside cylinder  16  and rests between the enlarged head of control rod  30  and the end wall of cylinder  16 . Spring  16  thereby serves as a force-limiting member that controls the maximum force that may be applied to control rod  30  so as to protect the jaws. Locking mechanisms, in the form of ratchet-type catches  56 ,  58 , may be provided so that the surgeon may lock the jaws in a closed position. 
     A rotation actuator, in the form of rotation knob  12 , may be provided to rotate the end effector mechanism. Rotation knob  12  is restrained from moving axially by spring clip or retaining ring  38  engaged in a cylindrical groove on handle housing  6 . Although rotation knob  12  does not move axially with respect to handle body  6 , it may rotate with respect to handle body  6 . Rotation knob  12  is rigidly attached to tubular barrel  10  so that rotation of rotation knob  12  is transferred to tubular barrel  10 . 
     Rotation may occur by application of force by the index finger to the outside of rotation knob  12 . When rotation knob  12  rotates, the rotational force is transferred to tubular barrel  10 . The rotational force is then passed to jaw  40  by pin  42  (see FIG. 2) and on to jaw  44 , and control rod  30 . Control rod  30  is free to rotate at its proximal end in cylinder  16 . 
     Control tube  32  may be moved axially by barrel sleeve  26 , which is a separate component from control tube  32  for manufacturing reasons, but is attached to control tube  32 . Barrel sleeve  26  in turn extends through an interior channel of a control member, in the form of cylindrical hub rack  24 . Barrel sleeve  26  is rotatably connected to hub rack  24  by retaining ring  14 . Hub rack  24  and barrel sleeve  26  thus move axially together but are able to rotate independently. Therefore, when rotation knob  12  is rotated, hub rack  24  does not rotate even though barrel sleeve  26  may rotate. In addition, control rod  30  is free to slide axially inside barrel sleeve  26  and control tube  32 . 
     To move jaw  44  axially and thereby roll a needle, hub rack  24  is moved axially, thereby moving barrel sleeve  26  and control tube  32  axially. Hub rack  24  is moved axially by rotating fingerwheel  8 . Fingerwheel  8  is mounted on handle body  6  and has an axle  36 . The axis of fingerwheel  8  may be tilted at an angle of approximately 80 degrees to the longitudinal axis of tubular barrel  10 . Fingerwheel  8  has spiral gear teeth cut in its end face that mesh with gear teeth in the side of hub rack  24 . Because the longitudinal axis of fingerwheel  8  is tilted, the gear teeth on fingerwheel  8  only mesh with the gear teeth on hub rack  24  on one side of fingerwheel  8  and do not interfere on the opposite side of fingerwheel  8 . 
     In operation, rotation of fingerwheel  8  results in axial translation of hub rack  24 , barrel sleeve  26 , and control tube  32 . Counter-clockwise rotation of fingerwheel  8  (as viewed from above) draws the elements proximally and thereby rolls the needle back toward the handle. Clockwise rotation of fingerwheel  8  pushes the elements distally and rolls the needle away from the handle (or clockwise when viewed from the left side). 
     FIG. 7 shows handle assembly  2  isometrically with rotation knob  12  partially cut away. The components of the barrel are shown connected together. Tubular barrel  10  is rigidly fixed to rotation knob  12 , which is free to rotate relative to handle body  6  but is restrained from moving axially. Barrel sleeve  26  (see FIG. 6) is attached to the proximal end of control tube  32 . The distal end of barrel sleeve  26  has a hexagonal section  28  which engages a hexagonal surface on the inside of rotation knob  12 . Rotation of rotation knob  12  thereby rotates tubular barrel  10  and control tube  32 . The rigid connections between these components helps prevent torsional windup. 
     FIG. 8 is an isometric view of fingerwheel  8  and hub rack  24  showing the mating of the gear teeth  9 ,  25 . Spiral-tooth gear  9  on the end of fingerwheel  8  engages curved-tooth rack  25  on hub rack  24  such that rotation of fingerwheel  8  causes axial translation of hub rack  24 . A longitudinal key  23  may be provided for engagement with a reciprocal groove in the handle body (not shown) to prevent hub rack  24  from twisting or rotating during axial translation. Hub rack  24  may also beformed in an elengated geometric form, such as a hexagon, to resist rotation. The axis of fingerwheel  8  may be slightly inclined so that spiral-tooth gear  9  meshes with curve-tooth rack  25  on one side of fingerwheel  8  but does not interfere on the opposite side. 
     FIGS. 9A and 9B show spiral-tooth gear  9  in side cross section and end view, respectively. Spiral-tooth gear  9  is cut on a cone with an inclined angle, forming a three-dimensional spiral-helix. The cone may be at an 80 degree angle to the longitudinal axis of fingerwheel  8 , as shown by the symbol theta. The angle could, however, range from 0 degrees to 90 degrees. The conical surface into which spiral-tooth gear  9  is cut is defined by an inside radius  31  of removed material and an outside radius  33 . Spiral-tooth gear  9  may be cut as a “double start,” meaning that there are two interleaved passes along the conical section, each 180 degrees out of phase with the other, as shown by S 1  and S 2  in the end view of fingerwheel  8  in FIG.  9 B. 
     FIGS. 10A and 10B show hub rack  24  in greater detail. To achieve more accurate engagement of the gear tooth surfaces, a curved-tooth profile  25  may be formed by standard tooth cut along two radii. The first radius  35  corresponds to the inside radius  31  of spiral-tooth gear  9 , and the second radius  37  corresponds to the outside radius  33  of spiral-tooth gear  9 . The paths of the two radial cuts making up the curved-tooth profile  25  may be tangent to one another and meet slightly offset from the projection of the center line upon the plane of the cut as shown in FIG.  10 A. First radius  35  may be equal to inside radius  31 , slightly greater than inside radius  31 , or slightly less than inside radius  31 . Second radius  37  is typically larger than outside radius  33 . 
     FIG. 11 shows another handle assembly wherein a fingerloop  60  controls axial motion of jaw  44 . As with the handle shown in FIG. 1, the surgical instrument has a handle assembly  2  on which is mounted a trigger lever  4 . A rotation actuator, in the form of a rotation knob  12  may also be provided on handle assembly  2 . Generally, handle body  6  may be held by a surgeon in either hand with a thumb through trigger lever  4 , leaving the index finger to operate rotation knob  12  and fingerloop  60 . A tubular barrel  10  may extend forward from handle assembly  2 , with rotation knob  12  at its proximal end. Tubular barrel  10  also has at its distal end an end effector  1  which consists of a pair of end effector pieces, shown in the figures as jaws  40 ,  44 . A pin  42  pivotably attaches jaw  40  to the distal end of tubular barrel  10 . 
     Handle assembly  2  may be configured to produce three separate motions in end effector  1 . First, rotation knob  12  may be turned to rotate tubular barrel  10  and thereby rotate end effector  1 , as shown by rotation arcs C 1  and C 2 . Second, trigger lever  4  may be squeezed toward handle assembly  2 , as indicated by rotation arc A 1 , to cause jaw  40  to conduct a “grasping” motion relative to jaw  44 , as indicated by rotation arc A 2 . Third, fingerloop  60  may be pulled in the proximal direction, as shown by arc B 1 , to make jaw  44  move proximally, as shown by arrow B 2 , and finger loop  60  may be pushed distally, as shown by arc B 1 , to make jaw  44  move distally, as shown by arrow B 2 . Axial sliding motion of jaw  44  may effect a rolling motion in a suture needle held between jaw  40  and jaw  44 . Another form of a thumb lever lock is also shown by locking surfaces  56 ,  58 . 
     FIG. 12 shows the internal mechanism of the handle assembly shown in FIG.  11 . Fingerloop  60  is pivotably mounted on pin  62 . Fingerloop  60  has a camming surface  64  on its proximal side internal to handle body  6 . Camming surface  64  contacts a proximal portion of collar  70 . Camming surface  63  on the side of fingerloop  60  opposite cam  64  contacts a distal portion of collar  70 . Collar  70  may be attached to control tube  32  so that pivoting of fingerloop  60  counter-clockwise (i.e., pulling fingerloop  60  proximally) draws collar  70  proximally, thereby drawing control tube  32  and jaw  44  proximally. Likewise, pivoting of fingerloop  60  clockwise (i.e., pushing finger loop  60  distally) causes camming surface  63  to push against the distal portion of collar  70  and effect distal motion in collar  70 , control tube  32 , and jaw  44 . Compression spring  66  bears against collar  70  on one end and against an interior surface of handle body  6  on its other end. Compression spring  68  bears against the end of rotation knob  12  on one end and against the distal portion of collar  70  on its other end. Together, compression springs  66 ,  68  provide counteracting biasing forces that cause fingerloop  60  to self-center when a surgeon releases pressure on fingerloop  60 . FIG. 12 also shows rotation knob  12  rotatably attached to handle body  6  by a retaining ring  72  and fixedly attached to tubular barrel  10 . 
     FIG. 13 shows another alternative handle assembly. Again, thumb trigger loop  4  is pivotably attached to handle body  6 . Rotation knob  12  is rotatably attached to handle body  6  and is rigidly attached to tubular barrel  10 . End effector  1 , comprising pivoting jaw  40  and sliding jaw  44 , is located at the distal end of tubular barrel  10 . Sliding of jaw  44  is effected by finger trigger  74 . Finger trigger  74  is operated by a pulling motion with an index finger, but is not normally moved by a pushing motion. 
     FIG. 14 shows the mechanism of FIG. 13 in partial section and in more detail. Finger trigger  74  is pivotably mounted on pin  62 , which is anchored in handle body  6  transverse to the longitudinal axis of tubular barrel  10 . Upper pawl  80  and lower pawl  82  are pivotably mounted on pins  78 ,  76  which are attached to finger trigger  74  at distances roughly equidistant above and below the centerline of a rack  84  that is attached to control tube  32 . Ratchet surfaces are cut into the perimeter of rack  84 . The surfaces may be wholly around rack  84  or may be flat surfaces on two sides of rack  84 . Pawls  80 ,  82  engage the ratchet surfaces of rack  84  under the biasing force of bias springs (not shown) which bias pawls  80 ,  82  into either engaged or disengaged position relative to rack  84 . The action of pawls  80 ,  82  may be synchronized so that only one pawl is engaged at a time. The bias springs are disposed to toggle over center upon each movement of finger trigger  74 . The springs thereby alternate which pawl is engaged, and also alter the direction of movement of rack  84 . Rack  84  is rotatably attached to control tube  32  by a shoulder and retaining ring (not shown) so that control tube  32  is not fixed to rack  84 , but instead may rotate with tubular barrel  10 , and control rod  30 , and rotation knob  12 . 
     In operation, pulling finger trigger  74  in the proximal direction engages either upper pawl  80  or lower pawl  82 , causing rack  84  to move either distally or proximally depending on which pawl is engaged. Finger trigger  74  may be return to its distal position under biasing force of spring  86 , which bears against an inside wall of handle body  6  and against a proximal edge of finger trigger  74 . 
     Successive pulls of finger trigger  74  cause alternating movement of sliding jaw  44 . For example, a first proximal pull on finger trigger  74  moves sliding jaw  44  proximally, with movement of sliding jaw  44  proportional to movement of finger trigger  74 . Releasing finger trigger  74  permits the bias springs on pawls  80 ,  82  to flip over center so that pawls  80 ,  82  are biased in the opposite direction. A second proximal pull on finger trigger  74  moves sliding jaw  44  distally a distance proportional to the amount of movement of finger trigger  74 . Releasing finger trigger  74  again flips the bias springs so that pawls  80 ,  82  are back to their original positions. By pulling finger trigger  74  only to the point of pawl engagement, a surgeon can produce successive movements of jaw  44  in the same direction. In this manner, a surgeon could roll a suture needle a few degrees in one direction without either releasing or grabbing the needle, or rolling it in the wrong direction. 
     As an alternative design, pawls  80 ,  82  could be replaced with hardened metallic or non-metallic balls contained in specially-shaped cavities. The cavities could be shaped as narrowing raceways or pockets against which the balls would rest. Springs bearing directly on the balls could force the balls into engagement with ratchet  84 . The balls could also be located in raceways or channels and contained in simple cages against which the bias springs could apply force. 
     FIG. 14 also shows a spherical ball  88  for transferring pivoting motion of thumb lever  4  into axial motion of control rod  30 . Ball  88  is mounted at the proximal end of control rod  30  and engages a cylindrical pocket  90  on the top of thumb lever  4 . Ball  88  permits control rod  30  to rotate with rotation knob  12  irrespective of the pivoted angle of thumb lever  4 . 
     FIG. 15 shows another alternative handle assembly. The assembly includes a thumb lever  4  pivotably attached to a handle body  6 , and a rotation knob  12  rotatably attached to handle body  6 . Finger trigger  74  extends downward from handle body  6 . Finger trigger  74  is pivotably mounted to handle body  6  by transverse pin  62 . A collar  70  is biased against the distal side of finger trigger  74  below pin  62  by spring  66 . Biasing force from spring  66  keeps finger trigger  74  biased in the distal direction and thereby keeps sliding jaw  44  (see FIG.  13 ), which is attached to finger trigger  74  by control tube  32 , biased in the distal direction. 
     Finger trigger  74  may be pulled proximally by an index finger, as shown by arc B 1 , and may cause collar  70  to move proximally, drawing control tube  32  and sliding jaw  44  proximally. Position of finger trigger  74  and jaw  44  may directly correlate with each other. Fully pulling finger trigger  74  in the proximal direction causes jaw  44  to move to its fully proximal position. 
     In operation, a needle may be rolled between jaws  40 ,  44  by first grasping the needle (by squeezing thumb lever  4 ) and then pulling on finger trigger  74  to cause jaw  44  to move proximally. Rolling a needle in the opposite direction may be accomplished by first pulling on finger trigger  74 , and then grasping the needle (by squeezing thumb lever  4 ) and releasing finger trigger  74  to cause jaw  44  to move distally. Increased pressure on thumb lever  4  results in a firmer grasp by jaw  40  on the needle. Increased force by jaw  40  increases the frictional force on the needle, locking sliding jaw  44  into position and decreasing the tendancy of the needle to roll. 
     FIGS. 16 and 18 show perspective views of two embodiments in which tubular barrel  10  and end effector assembly  1  may be coupled to a series of servomotors to enable surgery by a surgical robot. The device may be mounted on the end of a robot arm, which is not shown. The servomotors may be connected to the end effector assembly by force transducers and position encoders under microprocessor control. In FIGS. 16 and 18, tubular barrel  10  and the control members have been shortened to show the entire device. 
     FIG. 16 shows the housing  98  with servomotors  100 ,  102  having longitudinal axes which are transverse to the longitudinal axis of tubular barrel  10 . In FIG. 17, end effector assembly  1  is captured by a disconnecting mechanism in hub  114  which is attached to spur gear  112 . Spur gear  112  meshes with pinion  110 , which is driven by rotation servomotor  104 . Thus, operation of rotation servomotor  104  causes rotation of tubular barrel  10  and end effector assembly  1 . 
     Sliding jaw  44  (see FIG. 1) may be moved by control tube  32  (shown in FIGS. 2-4) which may be rotatably attached to rack member  108 . Control tube  32  thus moves axially with rack member  108  but may rotate with respect to rack member  108 . Rack member  108  may alternatively be cylindrical and may be rigidly attached to control tube  32 , so that rack member  108  rotates with tubular barrel  10  and disconnect hub  114 . Rack member  108  may translate in the axial direction under force from pinion  106  attached to gearmotor  100 . Thus, rotational force from gearmotor  100  may be translated through rack member  108  and control tube  32  to cause axial translation of slidable jaw  44 . 
     Pivoting jaw  40  (see FIG. 1) may be moved by control rod  30  (shown in FIGS. 2-4) which may be rotatably attached to rack member  107 . Control rod  30  thus moves axially with rack member  107  but may rotate with respect to rack member  107 . Rack member  107  may alternatively be cylindrical and may be rigidly attached to control rod  30 , so that rack member  107  rotates with tubular barrel  10  and disconnect hub  114 . Rack member  107  may translate in the axial direction under force from pinion  109  attached to gearmotor  102 . Thus, rotational force from gearmotor  102  may be translated through rack member  107  and control rod  30  to cause pivoting of pivoting jaw  40 . Servomotors  100 ,  102 ,  104  may be anchored by mounts attached to the housing (not shown), such as mount  111 . 
     FIG. 18 shows a handle assembly in which the longitudinal axes of the servomotors  100 ,  102  lie parallel to the longitudinal axis of tubular barrel  10 . In FIG. 19, end effector  1  is captured by a disconnecting mechanism in hub  114  which is attached to spur gear  112 . Spur gear  112  meshes with pinion  110 , which is driven by rotation servomotor  104 . Thus, operation of rotation servomotor  104  causes rotation of tubular barrel  10  and end effector assembly  1 . 
     Sliding jaw  44  may be moved by control tube  32  (shown in FIGS.  2 - 4 ), which may have a helical screw  116  cut about its proximal end. The helical screw on control tube  32  may mate with helical screw  118  on a shaft or gear mesh extending from servomotor  100 . The longitudinal axis of servomotor  100  is parallel to the longitudinal axis of control tube  32  so that the helical screws  116 ,  118  mate cleanly. Rotational force from servomotor  100  is transferred into axial motion by the helical screws  116 ,  118  and causes control tube  32  and sliding jaw  44  to move axially. 
     Likewise, pivoting jaw  40  may be moved by control rod  30  (shown in FIGS. 2-4) which may have a helical screw (not shown) cut about its proximal end. The helical screw on control rod  30  may mate with a helical screw (not shown) on a shaft or gear mesh extending from servomotor  102 . The longitudinal axis of servomotor  102  is parallel to the longitudinal axis of control rod  30  so that the helical screws mate cleanly. Rotational force from servomotor  102  is thus transferred into axial motion by the helical screws and causes control rod  30  to move axially and jaw  40  to pivot. On either servomotor  100  or servomotor  102 , the screws may take the form of male screws (as shown) mating with female screws on control tube  32  and control  30 . Alternatively, the forms could be female screws mating with male screws. 
     FIG. 20 shows a detachable end effector unit that may be used with a motorized handle. End effector assembly  1  consists of jaw  40  pivotably attached to tubular barrel  10 , and jaw  44  slidably disposed at the distal end of tubular barrel  10 . Disconnect coupling  92  is located at the proximal end of tubular barrel  10 . Disconnect coupling  92  may snap into hub  114 , as shown in FIGS. 17 and 19. Control tube  32  has a coupling  94  at its proximal end. Control rod  30  has a coupling  96  at its proximal end. Coupling  94  may be rigidly attached to control tube  32  so that both axial and rotational motion may be imparted to control tube  32  by coupling  94 . Likewise, coupling  96  may be rigidly attached to control rod  30  so that both axial and rotational motion may be imparted to control rod  30  by coupling  96 . Couplings  94 ,  96  may be comprised of, or may be attached to, hub racks, cylinders or collars, or any other structure that may impart appropriate motion to jaws  40 ,  44 . Couplings  94 ,  96  are shown in FIG. 20 having rack-tooth profiles, but they could also have helical screw threads, bayonet-style fittings, ball-and-detent snap fittings, or other conventional or quick-connect attachment mechanisms. 
     FIGS. 21A and 21B show another embodiment of the end effector mechanism, showing the pivoting of the jaw. Control rod  30  extends through the interior of control tube  32  and has link  31  connected to its distal end. Link  31  has a pin  39  connected transversely to the longitudinal axis of control rod  30 . Pin  39  is inserted into slot  41 . Slot  41  is cut in jaw  40 , which pivots on pin  42 . Pin  42  is attached to tubular barrel (not shown). Slot  41  is located proximally to pin  42 , while the clamping portion of jaw  40  is located distally to pin  42 . When control rod  30  is pushed distally with respect to the tubular barrel (not shown) in which pin  42  is mounted, pin  39  rides up slot  40 , which is cut at an angle relative to the motion of pin  39 . As pin  39  moves distally in slot  41 , it causes jaw  40  to open away from jaw  44 . When control rod  30  is pulled proximally with respect to the tubular barrel, pin  39  moves proximally is slot  41  and causes jaw  40  to close toward jaw  44 , as shown in FIG.  21 B. In this manner, jaw  40  can be closed to hold a needle  54  against jaw  44 . 
     Rolling of needle  54  is also shown in FIG.  21 B. With jaw  40  closed against jaw  44  so as to hold needle  54  tightly, control tube  32  may be moved in the distal direction, as shown by arrow A 1 . Axial motion of control tube  32  is translated into axial motion of jaw  44 . When jaw  44  moves, a shearing force is applied to needle  54  by jaw  40  and jaw  44 . The needle therefore rotates in the clockwise direction, as shown by rotation arc A 2 . Axial motion of control tube  32  in the proximal direction may likewise produce rolling of needle  54  in the counter-clockwise direction. 
     FIGS. 22A and 22B show another embodiment of the end effector. Control rod  30  and control tube  32  are disposed within tubular barrel  10 . Jaw  44  is attached to the distal end of control tube  32 . Jaw  40  is attached to the distal end of cantilever spring  29  which is in turn attached to the distal end of control rod  30 . Cantilever spring  29  is normally biased outward so that jaw  40  moves away from jaw  44 . The distal edge of tubular barrel  10  contacts the upper edge of cantilever spring  29  and limits the opening motion of cantilever spring  29 . Cantilever spring  29  increases in thickness from its proximal end to its distal end. Therefore, as cantilever spring  29  is drawn into tubular barrel  10  by distal motion of tubular barrel  10 , as shown by arrow A 6 , cantilever spring  29  pivots counter-clockwise and jaw  40  is forced downward toward jaw  44 , as shown by rotation arc A 3 . When tubular barrel  10  is drawn proximally with respect to control rod  30 , as shown by arrow A 6 , cantilever spring  29  forces jaw  40  away from jaw  44  under the natural outward bias of cantilever spring  29 . 
     A number of embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. As one example, the end effector could be attached to any device that is capable of transmitting motion to the end effector pieces. Accordingly, other embodiments are within the scope of the following claims.