Abstract:
A device is disclosed for introducing a flexible elongated element through at least two portions of a subject. In an embodiment, the device includes a proximal end and a distal end, as well as an advancement unit for longitudinally advancing the flexible elongated element toward the distal end such that a proximal end of the elongated element may pass from the distal end of said device with sufficient force to pass through the portions of the subject. The device also includes a securing unit for variably adjusting a securing force applied by the flexible elongated element to secure together the portions of the subject.

Description:
REFERENCE TO EARLIER APPLICATIONS 
     The present application claims the benefit of pending prior U.S. Provisional Patent Application Serial No. 60/118,039, filed Feb. 1, 1999 by Gregory E. Sancoff et al. for ENDOSCOPIC WIRE SUTURING DEVICE, and pending prior U.S. patent application Ser. No. 09/368,273, filed Aug. 3, 1999 by Gregory E. Sancoff et al. for SURGICAL SUTURING INSTRUMENT AND METHOD OF USE. 
     The two above-identified documents are hereby incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to medical instruments and procedures in general, and more particularly to suturing instruments and methods for suturing. 
     BACKGROUND OF THE INVENTION 
     Suturing instruments are typically used to draw together two or more portions of a subject patient (e.g., tissue such as muscle or skin) or to attach an object to the patient (e.g., to attach a piece of surgical mesh to the abdominal wall of the patient during hernia repair surgery). 
     Certain suturing instruments employ a needle that precedes a length of suture material through a subject. 
     For example, U.S. Pat. Nos. 3,470,875; 4,027,608; 4,747,358; 5,308,353; 5,674,230; 5,690,653; 5,759,188; and 5,766,186 generally disclose suturing instruments in which a needle, with trailing suture material, is passed through a subject. 
     U.S. Pat. Nos. 4,890,615; 4,935,027; 5,417,700; and 5,728,112 generally disclose suturing instruments in which suture material is passed through the end of a hollow needle after that needle has passed through a subject. 
     With all of the foregoing devices, a needle must be passed through the subject in order to deploy the suture. This is generally undesirable, since the needle typically leaves a larger hole in the subject than is necessary to accommodate only the suture material. In this respect it should be appreciated that it is generally desirable to alter each portion of the material being sutured as little as possible. 
     A suturing instrument has been devised which permits the suture material itself to pierce the subject without the use of a needle. However, this device does not permit sufficient flexibility with regard to the amount of tension that may be applied to the suture and tissue. 
     More particularly, U.S. Pat. No. 5,499,990 discloses a suturing instrument in which a 0.25 mm stainless steel suturing wire is advanced to the distal end of a suturing instrument, whereupon the distal end of the suturing wire is caused to travel in a spiral direction so as to effect stitches joining together two portions of a subject. After the spiral is formed, the beginning and end portions of the suture may be bent toward the tissue in order to inhibit retraction of the suture wire into the tissue upon removal of the suturing instrument. The stainless steel wire is sufficiently firm to hold this locking set. In addition, after the spiral is formed, the radius of the deployed suture spiral may then be decreased by advancing an outer tube over a portion of the distal end of the instrument. Again, the stainless steel wire is sufficiently firm to hold this reducing set. 
     Unfortunately, however, such a system does not permit sufficient flexibility in all situations with regard to the appropriate amount of tension to be applied to the subject, since the wire is relatively firm (i.e., firm enough to hold its sets). Such a system also does not provide sufficient flexibility with regard to the appropriate type of suture stitch to be applied, since the device is specifically configured to provide only a spiral suture stitch. 
     In contrast to the aforementioned limitations of the suturing instrument of U.S. Pat. No. 5,499,990, it is desirable that a suturing instrument approximate the portions of the material which is to be joined in the correct physiological relationship, and to urge the portions together with an appropriate amount of force. If too much force (or tension) is applied to the suture material, then the subject portions may become necrotic or the sutures may cut through the subject. If too little tension is applied to the suture material, then the healing process may be impaired. 
     U.S. Pat. No. 4,453,661 discloses a surgical instrument for applying staples. The staples are formed from the distal end of a length of wire. The distal end of the wire is passed through a subject, and thereafter contacts a die that causes the wire to bend, thereby forming the staple. The wire is sufficiently firm to take the set imposed by the die. The staple portion is then cut from the wire by a knife. Again, such a system suffers from the fact that it does not permit sufficient flexibility in all situations with regard to the appropriate tension to be applied to the subject, since the attachment is made by a staple which has a predefined geometry and is formed with relatively firm wire. In addition, the system is limited as to the type of fastening which may be applied, since the surgical instrument is limited to only applying wire staples. 
     There is a need, therefore, for a new suturing device that permits minimally disruptive suturing and permits flexibility in the placement, application, and tensioning of the suture material. 
     SUMMARY OF THE INVENTION 
     The invention provides a device for introducing a flexible elongated element through a subject. In one embodiment, the device includes a proximal end and a distal end, as well as an advancement unit for longitudinally advancing the flexible elongated element toward the distal end of the device such that a distal end of the flexible elongated element may pass from the distal end of the device with sufficient force to pass through the subject. The device also includes a securing unit for variably adjusting a securing force applied by the flexible elongated element so as to provide the desired securement to the subject. 
     In further embodiments, the device includes a guide tube for guiding the flexible elongated element through the device, toward the distal end of the device, as well as a rotation unit for rotating the distal end of the device so as to cause the flexible elongated element to wrap around itself, whereby to adjustably apply the securing force to the flexible elongated element. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiment of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein: 
     FIG. 1 is a side view of a suturing instrument formed in accordance with the present invention; 
     FIG. 2 is a partial side view, partially in section, of the suturing instrument shown in FIG. 1; 
     FIG. 3 is a partial top view, partially in section, of the suturing instrument shown in FIG. 1; 
     FIG. 4 is a schematic partial side view showing some of the internal components of the suturing instrument shown in FIG. 1; 
     FIG. 4A is a perspective view of a drive barrel assembly incorporated in the suturing instrument shown in FIG. 1; 
     FIG. 5 is a perspective view of a wire guide support unit incorporated in the suturing instrument shown in FIG. 1; 
     FIG. 6 is a perspective view of the suturing instrument&#39;s wire supply cartridge, which includes the wire guide support unit shown in FIG. 5; 
     FIG. 7 is a perspective view, partially in section, of the wire supply cartridge shown in FIG. 6; 
     FIG. 8 is a perspective rear view of the drive barrel assembly incorporated in the suturing instrument shown in FIG. 1, with the drive barrel assembly&#39;s release lever being shown in its closed position; 
     FIG. 9 is a perspective view of the proximal (i.e., rear) end of the drive barrel assembly shown in FIG. 8, with the release lever being shown in its open position; 
     FIG. 10 is a perspective view of the proximal (i.e., rear) end of the same drive barrel assembly, with the release lever being shown in its closed position, and with the wire guide and wire guide support unit being advanced relative to the drive barrel assembly (but with the remainder of the wire supply cartridge being removed from view); 
     FIG. 11 is a schematic view taken along the line  11 — 11  of FIG. 4; 
     FIG. 12 is a side view of a shaft and an end effector portion of the suturing instrument shown in FIG. 1; 
     FIG. 13 is a side view of the end effector portion of the suturing instrument shown in FIG. 1; 
     FIG. 14 is a side view, partially in section, of the end effector portion shown in FIG. 13, with the end effector portion being shown with its cutting bar in its forward (i.e., non-cutting) position; 
     FIG. 15 is a side view, partially in section, of the end effector portion shown in FIG. 14, but with the end effector portion being shown with its cutting bar in its retracted (i.e., cutting) position; 
     FIG. 16 is a perspective view of the end effector portion of the suturing instrument shown in FIG. 1; 
     FIGS. 17A-17J show various steps in a suturing operation conducted with the suturing instrument shown in FIG. 1; 
     FIG. 18 is a sectional view showing one possible construction for the suturing instrument&#39;s fixed jaw portion and its associated cutting bar; 
     FIG. 19 is a side view showing a piece of wire cut with the apparatus shown in FIG. 18; 
     FIG. 20 is a sectional view showing another possible fixed construction for the suturing instrument&#39;s fixed jaw portion and its associated cutting bar; 
     FIG. 21 is a side view showing a piece of wire cut with the apparatus shown in FIG. 20; 
     FIG. 22 is a side view, partially in section, of the end effector portion of the device, wherein the end effector portion includes a piezoelectric element to aid in wire penetration; 
     FIG. 23A is a schematic diagram of the device&#39;s fixed jaw portion, illustrating how the suture wire may sometimes curve as it exits the fixed jaw portion; 
     FIG. 23B is a schematic diagram of a modified form of the device&#39;s fixed jaw portion, illustrating how the profile of the device can be modified so as to counteract the aforementioned wire curvature; 
     FIG. 23C is a schematic diagram of a modified form of the device&#39;s movable jaw portion, illustrating how the mouth of the movable jaw portion&#39;s opening may be enlarged so as to facilitate suture capture; 
     FIG. 24 is a schematic diagram of a modified form of the device, wherein one or more legs have been provided to help stabilize the tissue during suturing; and 
     FIG. 25 is a schematic diagram of another modified form of the device, wherein a second set of jaws have been added to the device to help stabilize the tissue during suturing. 
     FIGS. 26A-45F show additional constructions of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Overview 
     Looking first at FIG. 1, there is shown a suturing instrument  10  which comprises a preferred embodiment of the present invention. Suturing instrument  10  includes a housing  12 , a handle  14 , a shaft  16  and an end effector  18 . Suturing instrument  10  also includes a wire advance button  20 , a jaw closing actuator  22 , a wire cutting actuator  24 , a left-thumb-actuated rotation button  26 , and a right-thumb-actuated rotation button  28  (FIG.  3 ). Suturing instrument  10  also includes a wire supply cartridge  30 , as well as a shaft retaining nut  32 . Shaft retaining nut  32  allows shaft  16  to be dismounted from the remainder of the device for cleaning purposes. 
     As will be discussed in further detail below, generally during use, suture wire (comprising wire formed of metal or any other suitable material having the required flexibility and stiffness) is drawn from a winding in wire supply cartridge  30  and is pushed through housing  12  and shaft  16  to end effector  18 , which includes a pair of opposing jaw portions. The jaw portions may be brought together around the material which is to be sutured by actuating jaw closing actuator  22  when the jaw portions are positioned at an appropriate surgical location. The suture wire is driven through housing  12  and shaft  16  to end effector  18  by actuating wire advance button  20 . The suture wire is driven from one jaw portion to the other jaw portion with sufficient force to penetrate the tissue placed between the jaw portions, and the suture wire is permitted to pass through the second jaw portion. The jaw portions are then permitted to separate and move away from the tissue, leaving the suture wire extending from the subject tissue to each of the two jaw portions. Shaft  16  and end effector  18  (together with wire supply cartridge  30 ) may then be rotated with respect to housing  12  and handle  14  by actuating either left-thumb-actuated rotation button  26  or right-thumb-actuated rotation button  28 . This causes the portions of the suture wire that extend from the tissue to be twisted about one another so as to form a closed loop extending through the tissue. It will be appreciated that the size of this closed loop may be adjustably reduced by increasing the degree of twisting in the wire. The twisted loop of suture wire may then be cut off, at end effector  18 , from the remaining portion of the suture wire that extends back through the suturing instrument. Such cutting may be effected by actuating wire cutting actuator  24 . 
     As will be discussed in further detail below, wire supply cartridge  30  may be supplied separately from suturing instrument  10 , with the wire supply cartridge  30  being loaded into suturing instrument  10  prior to commencing a suturing operation. As will also be discussed in further detail below, wire supply cartridge  30  may be disposable, such that the cartridge may be discarded after all of its wire has been used up. 
     Construction Details 
     As shown in FIGS. 2 and 4, handle  14  provides a cavity that may receive batteries  34 . In other embodiments, the unit may be powered remotely via a power transmission cord or any other source of suitable power. 
     Batteries  34  supply a ground (or negative) potential to a ground connector post  36  (FIG.  2 ), which in turn communicates with a rotary ground communicator  38 . Rotary ground communicator  38  permits electrical contact to be maintained with ground connector post  36  when rotary ground communicator  38  is rotated with respect to ground connector post  36 , as occurs when shaft  16  and end effector  18  are rotated so as to twist closed suture wire extending through the tissue. 
     Batteries  34  supply a positive potential to wire advance button  20 , and to a first connector post  40 , which in turn communicates with a first rotary electrical communicator  42 . First rotary electrical communicator  42  permits electrical contact to be maintained with first connector post  40  when first rotary electrical communicator  42  is rotated with respect to first connector post  40 . The positive potential from batteries  34  is also supplied (in parallel) to each thumb-activated rotation button  26 ,  28  (FIG.  3 ), and to a second connector post  44  (FIG.  2 ), which in turn communicates with a second rotary electrical communicator  46 . Again, second rotary electrical communicator  46  permits electrical contact to be maintained with second connector post  44  when second rotary electrical communicator  46  is rotated with respect to second connector post  44 . Each of the connector posts  36 ,  40  and  44  may be spring-biased so as to remain in contact with its respective rotary communicator. In view of the foregoing construction, the positive potentials may be switched on by depressing the respective actuator button  20 ,  26 ,  28 . Handle  14  also includes a cap  48  which may be removed so as to permit insertion of batteries  34 . 
     First rotary electrical communicator  42  is in electrical communication with a wire advance motor  50  shown in FIGS. 2 and 4. The output shaft of wire advance motor  50  is coupled to a miter drive gear  52 , which is in turn coupled to a miter follower gear  54 . Miter follower gear  54  is coupled to a drive wheel  56  which contacts the suture wire  58 , as will be described in further detail below with reference to FIGS. 5-10. 
     Second rotary electrical communicator  46  is in electrical communication with a shaft rotation motor  60  (FIGS.  3  and  4 ), the output of which is coupled to a pinion gear  62  (FIGS. 4,  4 A and  11 ) that rotates along an internal gear  64  (FIGS.  4  and  11 ). As shown in FIG. 3, left-thumb-actuated rotation button  26  and right-thumb-activated rotation button  28  may be provided to permit the user to use the thumb of either their left hand or their right hand, respectively, so as to actuate shaft rotation motor  60 . In this respect it will be appreciated that, inasmuch as left-thumb-actuated rotation button  26  and right-thumb-actuated rotation button  28  are wired in parallel, shaft rotation motor  60  will rotate in the same direction regardless of which button (i.e., button  26  or button  28 ) may be actuated. 
     Jaw closing actuator  22  (FIGS. 2 and 4) is coupled to a jaw linkage coupler  66 , which in turn contacts a jaw linkage  68  (FIGS.  2  and  14 ). When jaw closing actuator  22  is pulled toward handle  14  (FIG.  2 ), jaw closing actuator  22  pivots on its pivot pin  67  (FIG. 4) so as to drive jaw linkage coupler  66  distally, against the force of biasing spring  69 , and so as to cause the jaw linkage  68  to move forward toward the distal end of suturing instrument  10 . This action will in turn cause movable jaw portion  98  to close on fixed jaw portion  96  (FIG.  17 A), as will hereinafter be discussed in further detail. When jaw closing actuator  22  is subsequently released, biasing spring  69  (FIG. 4) drives jaw linkage coupler  66  proximally, so as to cause jaw linkage  68  to move proximally. This action will cause movable jaw portion  98  to open relative to fixed jaw portion  96  (FIG.  14 ), as will hereinafter be discussed in further detail. The action of jaw linkage  68  at the distal end of the device is discussed further below with reference to FIGS. 13 and 14. 
     Wire cutting actuator  24  is coupled to a wire cutting linkage coupler  70  (FIGS.  2  and  4 ), which in turn contacts a wire cutting linkage  72  (FIGS. 2,  14  and  15 ). When wire cutting actuator  24  is pulled toward handle  14  (FIG.  2 ), wire cutting actuator  24  pivots on its pivot pin  73  (FIG. 4) so as to drive wire cutting linkage coupler  70  proximally, against the force of biasing spring  69 , and so as to cause wire cutting linkage  72  to move proximally, away from the distal end of suturing instrument  10 . This action will in turn cause cutting bar  104  (FIG. 14) to move proximally (FIG. 15) so as to effect wire cutting, as will hereinafter be discussed in further detail. When wire cutting actuator  24  is subsequently released, biasing spring  69  drives wire cutting linkage coupler  70  distally, so as to cause wire cutting linkage  72  to move distally. This action causes cutting bar  104  to move distally, so as to assume the position shown in FIG.  14 . Wire cutting linkage  72  moves adjacent to, and independent of, jaw linkage  68  discussed above. The action of wire cutting linkage  72  at the distal end of the device is discussed further below with reference to FIGS. 14 and 15. 
     The wire supply cartridge  30  shown in FIG. 1 includes a wire guide support unit  74 , as shown in FIGS. 5-7. A supply coil of suture wire  58  (comprising wire formed of metal or any other suitable material having the required flexibility and stiffness) may be supplied in the base of cartridge  30  and is fed into the support unit  74  as shown in FIG. 7. A wire guide  76  surrounds suture wire  58 , from support unit  74  to the distal end of suturing instrument  10 , adjacent to end effector  18  (FIGS. 5-7,  14  and  15 ). Wire guide  76  ensures that suture wire  58  does not bend or buckle as the suture wire is pushed through housing  12  and shaft  16 . More particularly, wire guide  76  preferably forms a sufficiently close sliding fit with suture wire  58  such that suture wire  58  cannot bend or buckle as the suture wire is advanced through suturing instrument  10 . At the same time, wire guide  76  is also formed so as to present a minimum of friction to suture wire  58  as the suture wire is advanced through the instrument. The foregoing characteristics are important, inasmuch as suture wire  58  is extremely thin and flexible and highly susceptible to bending or buckling in the absence of some sort of lateral support. 
     By way of example but not limitation, where suture wire  58  is formed out of stainless steel and has a diameter of 0.005 inch, wire guide  76  might have an inside diameter of 0.008 inch and an outside diameter of 0.016 inch. In addition, wire guide  76  is preferably formed out of polytetrafluoroethylene (PTFE) or some other relatively lubricious material. Alternatively, the interior of wire guide  76  may be coated with a lubricant so as to facilitate closely-supported, low-friction passage of the suture wire through the wire guide. 
     Further by way of example but not limitation, in one preferred form of the invention, suture wire  58  may comprise 316 LVM stainless steel having a tensile strength of 170 kpsi. 
     Although wire guide  76  extends through support unit  74  (FIG.  7 ), wire guide  76  has two openings  78  (one on either side of wire guide  76 , only one of which is shown in FIG. 5) in the center of support unit  74 . Openings  78  expose a portion of suture wire  58  so that wire drive wheel  56  (FIG. 8) may contact suture wire  58  and urge the suture wire forward toward the distal end of suturing instrument  10 , as will be discussed in detail below with reference to FIGS. 8-10. 
     As shown in FIGS. 2,  3 ,  4 A and  8 , housing  12  receives a drive barrel assembly  80  that contains the aforementioned motors  50  and  60 , and provides a distally-extending barrel shaft  81  (FIGS.  4 A and  8 ), on the outside of which are located the rotary communicators  38 ,  42  and  46 ′. A recess  82  (FIG. 4A) is provided on the distal end of barrel shaft  81  for receiving a coupling pin  84  (FIGS. 2 and 4) which is located on the proximal end of shaft  16 , such that rotation of drive barrel assembly  80  causes rotation of coupling pin  84  and hence shaft  16 . Drive barrel assembly  80  is rotationally held within housing  12  by bearings  86 , as shown in FIGS. 2 and 3. 
     Looking next at FIGS. 7-10, wire supply cartridge  30  may be attached to drive barrel assembly  80  by rotating a release lever  87  away from the center of drive barrel assembly  80  (FIGS.  8  and  9 ), so as to move a carriage  88  relative to drive barrel assembly  80 . Most particularly, release lever  87  rides on a pin  90 , and rotation of release lever  87  from the position shown in FIG. 8 to the position shown in FIG. 9 draws carriage  88 , as well as a wire follower wheel  92 , away from the center of drive barrel assembly  80 . Once wire follower wheel  92  is separated from wire drive wheel  56  by a sufficient distance to expose the drive barrel assembly&#39;s central passageway  93  (FIG.  9 ), wire guide  76  (overlying suture wire  58 ) may be inserted into passageway  93  (FIG.  10 ), and wire guide support unit  74  (FIGS. 6,  7  and  10 ) may be inserted between wheels  56  and  92  (FIG.  10 ), such that wheels  56  and  92  contact either side of suture wire  58  through openings  78  formed in either side of wire guide  76 . A biasing spring  94  (FIGS. 8-10) is provided on carriage  88  to urge wire follower wheel  92  into close contact with suture wire  58 . In other embodiments, wire follower wheel  92  may also be driven indirectly by wire drive wheel  56  in order to provide additional forces to move suture wire  58  distally (i.e., forward, toward the tool&#39;s end effector  18 ). 
     Pinion gear  62  (FIGS. 4,  4 A and  11 ) extends distally from drive barrel assembly  80  and engages the housing&#39;s internal gear  64 , as shown in FIGS. 4 and 11. As a result of this construction, when shaft rotation motor  60  is actuated, pinion gear  62  rotates around internal gear  64 , bringing with it the entire drive barrel assembly  80 . This in turn causes shaft  16  to rotate, since shaft  16  is coupled to drive barrel assembly  80 . More particularly, the rotation of drive barrel assembly  80  is transferred to shaft  16  through the shaft&#39;s coupling pin  84  (FIGS. 2,  4  and  12 ), which is seated in recess  82  (FIG. 8) of drive barrel assembly  80 . 
     End effector  18  (FIGS.  1  and  13 - 16 ) includes a fixed jaw portion  96  and a movable jaw portion  98 . Movable jaw portion  98  is coupled to the aforementioned jaw linkage  68  (FIG. 14) via a jaw linkage pin  100 , such that when jaw linkage  68  is moved distally (i.e., by pulling jaw closing actuator  22  toward handle  14 ), jaw portion  98  is rotated about a pivot pin  102  (FIG. 13) and closes onto fixed jaw portion  96 . Conversely, when jaw linkage  68  is moved proximally (i.e., by the power of biasing spring  69  acting on jaw linkage coupler  66  and hence jaw linkage  68 ), movable jaw portion  98  will open away from fixed jaw portion  96 . It will be appreciated that the force of biasing spring  69  will normally keep movable jaw portion  98  open relative fixed jaw portion  98  (FIGS. 1,  13  and  14 ), unless and until jaw closing actuator  22  is activated so as to overcome the bias of spring  69 . 
     Wire cutting linkage  72  (FIGS. 2,  3 ,  14  and  15 ) is coupled to a cutting bar  104  (FIGS. 14 and 15) that includes a small opening  106  through which suture wire  58  may pass, as will hereinafter be discussed in further detail. Preferably cutting bar  104  is slidably received in a passageway  107  (FIGS. 14,  15 ,  16  and  17 H) formed in fixed jaw portion  96 . In one position (FIG.  14 ), cutting bar  104  is positioned in fixed jaw portion  96  such that the cutting bar&#39;s opening  106  is aligned with a channel  108  formed in fixed jaw portion  96 , whereby suture wire may be passed from the distal end of wire guide  76 , through channel  108  formed in fixed jaw portion  96  (where it undergoes an approximately  90  degree change of direction), through opening  106  in cutting bar  104 , through a channel extension  108 A formed in fixed jaw portion  96 , and across to movable jaw portion  98 , as will hereinafter be discussed in further detail. However, when wire cutting linkage  72  is moved proximally by pulling wire cutting actuator  24  toward handle  14 , cutting bar  104  is also moved proximally (FIG. 15) so as to cut any suture wire extending from channel  108  (in fixed portion  96 ) into opening  106  (in cutting bar  104 ). In this respect it will be appreciated that it is desirable to form channel extension  108 A with a length greater than channel  108  (see FIGS. 14 and 15) so as to prevent the suture wire from being cut in two places (i.e., at channel  108  and again at channel extension  108 A) when cutting bar  104  is moved proximally by pulling on wire cutting actuator  24 . At the same time, however, it should also be appreciated that the fixed jaw portion&#39;s channel  108  and channel extension  108 A, and the cutting bar&#39;s opening  106 , are all sized, relative to suture wire  58 , so as to provide as much support as possible to the suture wire as it passes through, and out of, fixed jaw portion  96 . 
     It will be appreciated that the force of biasing spring  69  will normally keep cutting bar  104  in its distal position (i.e., with the cutting bar&#39;s opening  106  aligned with the fixed jaw portion&#39;s channel  108 ), unless and until wire cutting actuator  24  is activated so as to overcome the bias of spring  69 . 
     In view of the foregoing construction, it will be seen that: (1) release lever  87  (FIGS. 8-10) may be activated so as to move wire follower wheel  92  away from, and toward, wire drive wheel  56  so as to permit a full wire supply cartridge  30  (FIGS.  1  and  5 - 7 ) to be loaded into suturing instrument  10 ; (2) activating jaw closing actuator  22  will cause movable jaw portion  98  to close on fixed jaw portion  96 ; (3) activating wire advance button  20  will cause wire drive wheel  56  to advance suture wire  58  through housing  12  and shaft  16 ; (4) activating rotation button  26  and/or rotation button  28  will cause shaft  16  to rotate relative to housing  12 ; and (5) activating wire cutting actuator  24  will cause cutting bar  104  to move proximally so as to sever any suture wire extending from fixed jaw portion  96 . 
     Operation 
     Suturing instrument  10  may be used to apply wire suture  58  to a subject so as to effect a desired suturing operation. 
     By way of example but not limitation, and looking now at FIGS. 17A-17J, suturing instrument  10  may be used to suture together two portions  110 ,  112  of a subject which is to be sutured. In a typical case, portions  110 ,  112  might comprise two sections of severed tissue which need to be reattached to one another, or two pieces of previously unattached tissue which need to be attached to one another. However, one or the other of the portions  110 ,  112  might also comprise artificial mesh or some other object being attached to tissue, etc. In addition, in a typical case, portions  110 ,  112  might be located relatively deep within a patient, and might be accessed during a so-called “minimally invasive”, or a so-called “closed surgery”, procedure; however, in other circumstances, portions  110 ,  112  might be accessed during a conventional, or so-called “open surgery”, procedure. This later situation might include procedures done at the outer surface of the patient&#39;s body, i.e., where portions  110 ,  112  comprise surface subjects. 
     In any case, suturing instrument  10  is initially prepared for use by installing batteries  34  into handle  14 , if batteries  34  are not already installed, and by installing wire supply cartridge  30  into the suturing instrument, if a cartridge  30  is not yet installed. As noted above, wire supply cartridge  30  is installed in suturing instrument  10  by (1) moving the drive barrel assembly&#39;s release lever  87  to its open position (FIG.  9 ), so as to move wire follower wheel  92  away from wire drive wheel  56  and thereby expose the barrel assembly&#39;s central passageway  93 ; (2) passing the distal end of the cartridge (i.e., the distal end of wire guide  76 ) through drive barrel assembly  80  and shaft  16  until the distal end of wire guide  76  is in communication with the channel  108  formed in fixed jaw portion  96  (FIG.  14 ), at which point the cartridge&#39;s wire guide support unit  74  will be positioned intermediate wire drive wheel  56  and wire follower wheel  92  (FIG.  2 ); and (3) moving the drive barrel assembly&#39;s release lever  87  back to its closed position (FIG.  8 ), so as to cause wire drive wheel  56  and wire follower wheel  92  to extend through the wire guide&#39;s openings  78  and engage suture wire  58 . 
     At this point suturing instrument  10  will be ready for use, with its movable jaw portion  98  being opened away from its fixed jaw portion  96 , and with its cutting bar  104  being in its forward (FIG. 14) position. 
     Next, suturing instrument  10  has its movable jaw portion  98  moved into engagement with its fixed jaw portion  96  (i.e., the jaws  96 ,  98  are placed in their “closed” position) by pulling jaw closing actuator  22  toward handle  14 , and then the distal end of suturing instrument  10  is moved adjacent to subject portions  110 ,  112  (FIG.  17 A). 
     In the case of a so-called closed surgical procedure, such positioning will generally involve moving the distal end of the suturing instrument through a cannula and into an interior body cavity; however, it is also envisioned that one might move the distal end of the suturing instrument directly into an otherwise-accessible body cavity, e.g., directly into the colon or esophagus, etc. In the case of a so-called open surgical procedure, such positioning might involve positioning the distal end of the suturing instrument adjacent to more readily accessible subject portions  110 ,  112 . 
     In any case, once the distal end of suturing instrument  10  has been placed adjacent to subject portions  110 ,  112 , jaw closing actuator  22  is released, such that biasing spring  69  (FIG. 4) will cause movable jaw portion  98  to open away from fixed jaw portion  96  (FIG.  17 B). Then the distal end of suturing instrument  10  is moved so that its jaws  96 ,  98  straddle subject portions  110 ,  112 , and then jaw closing actuator  22  is actuated again, by pulling jaw closing actuator  22  toward handle  14 , so as to close movable jaw portion  98  against fixed jaw portion  96 , whereby to capture subject portions  110 ,  112  (FIG.  17 C). 
     Next, wire advance button  20  is activated so as to cause suture wire  58  to be driven forward, out of the distal end of wire guide  76 , through the fixed jaw portion&#39;s channel  108 , through opening  106  in cutting bar  104 , through the fixed jaw portion&#39;s channel extension  108 A, through subject portions  110 ,  112 , and finally through an opening  113  (FIGS. 14,  15  and  17 C) formed in movable jaw portion  98 . Suture wire  58  is preferably advanced so that a length  58 A of wire  58  extends approximately 1 centimeter out of the bottom end of movable jaw portion  98  (FIG.  17 C). In this respect it will be appreciated that, as suture wire  58  leaves fixed jaw portion  96  and engages subject portions  110 ,  112 , the fixed jaw portion&#39;s channel  108 , the cutting bar&#39;s opening  106  and the fixed jaw portion&#39;s channel extension  108 A will support the thin suture wire so as to enable the suture wire to penetrate subject portions  110 ,  112 . 
     Once this has been done, jaw closing actuator  22  is released so as to permit movable jaw portion  98  to return to its “open” position relative to fixed jaw portion  96 , and then wire advance button  20  is used to pay out additional suture wire  58  as the distal end of suturing instrument  10  is stepped back (e.g., by about a centimeter or so) from subject portions  110 ,  112  (FIG.  17 D). 
     Then jaw closing actuator  22  is used to move jaw portion  98  back into engagement with fixed jaw portion  96  once more (FIG.  17 E). 
     Next, left-thumb-actuated rotation button  26 , or right-thumb-actuated rotation button  28 , is used to rotate shaft  16  and hence end effector  18 . This causes suture wire  58  to twist on itself, initially creating a relatively large loop  116  (FIG. 17F) of suture wire  58  extending from subject portions  110 ,  112  toward suturing instrument  10 . However, as rotation button  26  and/or rotation button  28  is used to rotate shaft  16  (and hence end effector  18 ) more and more, the loop  116  of suture material will progressively close down (FIG. 17G) so as to form a tight binder for subject portions  110 ,  112 . In this respect it will be appreciated that the longer the period of time that end effector  18  is rotated, the greater the amount of twisting of suture wire  58 , and the greater the force holding subject portions  110 ,  112 . In this respect it will also be appreciated that suture wire  58  is preferably carefully selected with respect to its flexibility relative to the strength of subject portions  110 ,  112 . In particular, suture wire  58  is chosen so as to have a flexibility such that the suture wire will twist, and loop  116  will close down, before subject portions  110 ,  112  will undergo substantial deformation and/or tearing. By way of example but not limitation, in practice, it has been found that 0.005 inch diameter stainless steel wire can be used with most types of mammalian tissue such that the suture wire can be twisted closed without causing substantial deformation and/or tearing of the tissue. 
     Once suture wire  58  has been tightened to the desired degree, rotation of shaft  16  and end effector  18  is stopped, i.e., by releasing button  26  or button  28 . Then wire cutting actuator  24  is depressed (e.g., it is pulled back toward handle  14 ) so as to pull cutting bar  104  proximally and thereby sever the suture wire  58  as the suture wire emerges from the fixed jaw portion&#39;s channel  108  and enters the cutting bar&#39;s opening  106  (FIG.  17 H and FIG.  16 ). This action separates the deployed suture wire extending through subject portions  110 ,  112  from the suture wire remaining in wire supply cartridge  30 , wire guide  76  and the fixed jaw portion&#39;s channel  108 . 
     Then wire cutting actuator  24  is released, allowing biasing spring  69  to return cutting bar  104  to return to its distal position, and then jaw closing actuator  22  is released, allowing movable jaw portion  98  to move away from fixed jaw portion  96 . Suturing instrument  10  may then be removed from subject portions  110 ,  112 , which action will pull wire length  58 A from movable jaw portion  98  (FIG.  17 I). 
     The deployed suture wire  58  may then be pressed down flat against subject portions  110 ,  112 , or rounded into a ball, or otherwise operated upon, so as to reduce the profile of, or reduce the tendency to snag on, the deployed suture wire (FIG.  17 J). 
     It will be appreciated that suturing instrument  10  will have application in a broad range of different suturing operations. More particularly, it will be appreciated that suturing instrument  10  will have application in both “open” and “closed” surgical procedures, with the former including, but not limited to, large entry procedures, relatively shallow procedures, and surface procedures; and with the latter including, but not limited to, surgical procedures where access is gained to an interior structure through the use of a cannula, and surgical procedures where access is gained directly to an internal body cavity without the use of a cannula, e.g., such as a procedure conducted within the colon or the esophagus. 
     It will also be appreciated that suturing instrument  10  will have application where two portions of tissue must be attached to one another (e.g., where two severed pieces of tissue must be re-attached to one another, or where two separate pieces of tissue must be attached to one another, or where two sections of a single piece of tissue must be approximated to one another), and where an object must be attached to the patient (e.g., where surgical mesh must be attached to the patient&#39;s abdominal wall during hernia repair surgery, etc.). 
     Among other things, it is believed that suturing instrument  10  will have particular application in the areas of general laparoscopic surgery, general thoracic surgery, cardiac surgery, general intestinal surgery, vascular surgery, skin surgery and plastic surgery. 
     Looking next at FIGS. 18 and 19, it will be seen that where the fixed jaw portion&#39;s channel  108  is disposed so as to be substantially aligned with the center of cutting bar  104  (FIG.  18 ), suture wire  58  will be cut with a relatively flat leading end  58 B (FIG.  19 ). However, it has sometimes been found helpful to provide suture wire  58  with a relatively sharp leading point. Such a leading point can help open the subject for the following portion of the suture wire. In addition, such a leading point can help the suture wire penetrate the subject with a substantially straight path, so that the suture wire will reliably enter the movable jaw portion&#39;s opening  113 . To this end, it has been found that moving the fixed jaw portion&#39;s channel  108  off-center relative to cutting bar  104  (FIG. 20) will cause the leading end  58 B of suture wire  58  to be formed with a relatively sharp tip  58 C (FIG.  21 ). 
     It is also possible to use suturing instrument  10  to ligate a subject rather than to pass a suture through the subject. For example, suturing instrument  10  might be used to ligate a blood vessel with suture wire  58 . In this case, suturing instrument  10  is deployed so that suture wire  58  will pass around the far side of the subject, rather than through the subject as in the case of the suturing operation of the type described above. 
     By way of example but not limitation, in a typical ligating operation, movable jaw portion  98  is first opened relative to fixed jaw portion  96 . Then suturing instrument  10  is positioned about the subject so that when movable jaw portion  98  is thereafter closed toward fixed jaw portion  96 , the fixed jaw portion&#39;s channel  108  and the movable jaw portion&#39;s opening  113  will both lie on the far side of the subject. The movable jaw portion  98  is then closed against the fixed jaw portion  96 , and suture wire  58  is passed from fixed jaw portion  96  to movable jaw portion  98 , i.e., around the far side of the subject. The movable jaw portion  98  is then opened, and suture wire  58  is payed out as the instrument is stepped back from the subject. Then the movable jaw portion  98  is again closed against the fixed jaw portion  96 . The shaft of the instrument is then rotated so as to form, and then close down, the ligating loop. Then cutting bar  104  is activated so as to cut the ligating loop from the remainder of the suture wire still in the tool, the movable jaw member  98  is opened, and the instrument is withdrawn from the surgical site. The deployed suture wire  58  may then be pressed down flat against the subject, or rounded into a ball, or otherwise operated upon, so as to reduce the profile of, or reduce the tendency to snag on, the deployed suture wire. As will be appreciated by a person skilled in the art, where instrument  10  is to be used for ligating purposes, fixed jaw portion  96  and movable jaw portion  98  might be formed with a greater longitudinal length so as to facilitate passing the suture wire around the far side of the subject. Furthermore, movable jaw member  98  might be formed with a recess, intermediate its jaw linkage pin  100  (FIG. 15) and its opening  113 , for accommodating the subject, whereby to prevent compressing the subject when movable jaw member  98  is moved into engagement with fixed jaw member  96 . 
     Suture wire  58  may comprise a wire formed out of a metal or any other suitable material having the required flexibility and stiffness. By way of example but not limitation, suture wire  58  may comprise stainless steel, titanium, tantalum, etc. 
     If desired, suture wire  58  may also be coated with various active agents. For example, suture wire  58  may be coated with an anti-inflammatory agent, or an anti-coagulant agent, or an antibiotic, or a radioactive agent, etc. 
     Looking next at FIG. 22, it is also possible to impart ultrasound energy to the wire in order to make tissue penetration easier. More particularly, because of the small cross-sectional area of the wire and the propensity for the wire to buckle when axially loaded, it is beneficial to be able to advance the wire into tissue with a minimum of load. This can be achieved by appropriately applying ultrasound energy to the wire. 
     A piezoelectric element  200  is placed at the outside radius of the wire guide path  108  at the right angle bend in the fixed jaw portion  96  just before where the wire enters the tissue. The piezoelectric element  200  vibrates at a position along this bend such that it supports the wire in completing the turn but also imparts a component of displacement in the direction of the tissue. Displacement of this kind at ultrasonic frequencies, in addition to the existing wire driving means, would cause the tip of the wire to penetrate the tissue using less force. In addition to reducing the tendency for outright wire buckling, lowering the wire loads will also allow the wire penetration to proceed in a straighter path. 
     Looking next at FIG. 23A, it will be seen that, in some circumstances, the suture wire  58  may exit fixed jaw portion  96  with a curvature, due to the fact that suture wire  58  follows a curved channel  108  in fixed jaw portion  96 . In some cases this curvature in the suture wire  58  may be quite modest, so that it may be effectively ignored. However, in other circumstances, this curvature might be large enough to cause the suture wire advancing out of fixed jaw portion  96  to miss the target opening  113  in movable jaw portion  98 . In this case the curvature in suture wire  58  can present a significant problem. However, and looking now at FIG. 23B, it has been found that the profile of the cutting bar&#39;s opening  106  may be modified so as to provide a deflecting die which will counteract undesirable curvature in the suture wire and return the suture wire to a straight path as the suture wire exits fixed jaw portion  96 . Alternatively, the profile of the fixed jaw portion&#39;s channel  108  may be modified, adjacent to cutting bar  104 , so as to provide a similar deflecting die which will counteract undesirable curvature in the suture wire and return the suture wire to a straight path as the suture wire exits fixed jaw portion  96 . Furthermore, and looking now at FIG. 23C, the mouth of the movable jaw portion&#39;s opening  113  may be enlarged to help capture a suture wire deviating from a straight path. 
     Looking next at FIG. 24, it will be seen that one ore more legs  300  may be provided on suturing instrument  10 , wherein legs  300  help stabilize the tissue during suturing. 
     And looking next at FIG. 25, it will be seen that a grasper  400 , comprising jaws  405  and  410 , may be added to suturing instrument  10  to help stabilize the tissue during suturing. 
     If desired, the end effector  18  of suturing instrument  10  may be constructed so as to have two movable, opposing jaws, rather than one fixed jaw and one movable jaw as described above. 
     Also, if desired, shaft rotation motor  60  and thumb buttons  26 ,  28  may be configured so that depressing one button (e.g., button  26 ) will cause end effector  18  to rotate in one direction (e.g., clockwise), and depressing the other button (e.g., button  28 ) will cause end effector  18  to rotate in the opposite direction (e.g., counterclockwise). 
     Further Constructions for the Wire Suturing Device 
     Other Suture Materials 
     It is possible to use other suture wire materials provided they are stiff enough to penetrate the tissue. Other medical grade metals such as ASTM 1341 titanium and ASTM F 1091 cobalt-chromium alloy. Plastic materials that are sufficiently stiff could also be used such as polymide thermoplastics, Nylon, and polypropylene. 
     Collet Wire Drive Mechanism 
     Pushing the wire forward could also be done using a collet system such as sometimes used to drive lead in a mechanical pencil. The collet system could be smaller than the drive wheel mechanism and would allow it to be placed near the end of the instrument shaft. The collet would hold the wire and a mechanism would then push the collet and wire forward. An example of a collet wire drive mechanism  500  is shown in FIGS. 26A-26E. A spring  505  presses a collet collar  510  onto collet  515  which causes collet  515  to squeeze and hold wire  520 . The taper of collet  515  is such that collet collar  510  is now stuck on the collar and no longer needs spring force bias to maintain the hold on wire  520 . As the collet assembly  500  is moved forward by a force against the push collar  510 , wire  520  is also moved forward until the collet collar  510  hits a collet collar stop  525  at the end of the advance stroke. At this point collet collar  510  is pushed off the collet  515  thereby releasing the hold on wire  520  so that as the collet assembly  500  moves backwards wire  520  remains in its advanced position. As the collet assembly  505  moves all the way back, collet collar  510  encounters the collet collar backstop  530  which pushes collar  510  back onto the collet  515  with the force of spring  505  so that wire  520  is held again and ready for another thrust forward. Various methods can be used to advance push collar  535  such as a pivoting manual lever mechanism  540  and a motorized cam system  545 , both shown in FIGS. 26A-26E. 
     As the collet  515  advances, wire  520  in front of collet  515  needs to be supported to prevent wire  515  from buckling, yet the support must shrink and expand with the motion of the collet movement. As shown in FIGS. 27A-27D, methods for providing this support are to place wire  520  inside a small coil spring  550 , a tube  555  of an elastomeric material, or a telescoping tubes  560 . 
     Because collets for very small wires can be difficult to manufacture, small pieces of plastic tubing  565  with a small internal diameter sufficient to accommodate the wire with some clearance, can be placed in collet  515  as an interface between collet  515  and the wire. The deformability of the plastic tubing will allow collet  515  to collapse plastic tube  565  enough to press and hold the wire (see FIGS.  28 A and  28 B). The plastic can be chosen such that the coefficient of friction between the plastic and wire is very high, thereby reducing the forces required to hold the wire. When collet  515  is released the plastic tube has sufficient resilience to open the internal diameter and provide clearance between the wire and the inside of the plastic tube. As collet  515  moves backwards after advancing the wire, the wire will remain in the incrementally forwarded position. 
     Wire Cutting 
     It is advantageous to cut wire  520  with a minimum of force since the mechanism for cutting wire  520  has to be at the end of a small shaft. Providing the cutting surfaces with stress concentrators  570 ,  575  can substantially reduce the load required to cut the wire (see FIGS. 29-29D,  30 ). 
     It is also advantageous to provide wire  520  with a sharp tip  580  after cutting so that when it is pushed through tissue during the next suture placement it can be done with a minimum of force. Forcing a symmetric wedge-shaped cutting surface  570  into wire  520  from both sides will cause wire  520  to have a tip  585  with sloped sides making it sharper for tissue penetration (see FIGS.  29 - 29 D). A cutting bar  590  that shears wire  520  at an angle to the length of wire  520  will create a correspondingly angled tip  595 . This could be done for example if the wire path  600  traversed a circular cutting bar nearer one side of the bar rather than the middle (see FIGS.  31  and  31 A). 
     Wire Feed Stop 
     The moveable side of the jaw that accommodates the distal end of wire  520  as it passes through tissue  605  may include a stop to prevent excess wire advancement into surrounding tissues in surgical settings where it is difficult to see. The stop can be as simple as a physical end  610  to the hole in the jaw that the wire moves into after it has passed through the tissue. Alternatively, the wire end could be sensed as it passes into the moveable side of the jaw with devices such as an optical interrupter  615 , pressure switch  620 , or the like that would be used to provide an audible, tactile, or visual feedback to the surgeon indicating that they should stop advancing wire (see FIGS.  32 A- 32 H). 
     Jaw Surfaces That Enhance Tissue Grasping 
     A large function of the jaw is to bring together the two pieces of tissue that are to be sutured. To facilitate this, the jaw surface may have undulations  625 , abrasive surfaces  630 , or concave areas  635  that create a ridge at the tip of the jaw. The jaw may also be tapered to a pointed tip  640  to increase its ability to pinch or isolate smaller sections of tissue. During hernia repairs, it is often necessary to attach a tightly woven mesh to the inside of the abdominal wall. The mesh can be anchored by using sutures placed through the mesh and into the tissue on the other side. In order for this to be feasible with the present device, the jaws must be able to grab a substantially flat section of mesh overlying tissue and pinch them in order to position them in the jaw. Once the mesh and tissue is properly positioned in the jaw, the wire can be passed through the tissue and twisted as is normally done (see FIGS.  33 A- 33 G). 
     Jaw Feature That Facilitates Wire Penetration 
     A raised portion  645  on the jaw surface where wire  520  exits and also on the opposite jaw surface through which wire  520  passes after penetrating tissue  605 , can reduce the travel distance of the wire. This reduces the chances that the wire will deviate from the intended path through the tissue (see FIGS.  34 A and  34 B). 
     Tubular Ligation 
     It is often necessary to surgically occlude a tubular structure  650  by tying a suture  655  tightly around the circumference so that the lumen is collapsed and closed. By placing a space  660  in the jaw proximal to where wire  520  emanates, tubular structure  650  can be held in the closed jaw while wire is passed around the distal side of the structure. The jaw is then opened and pulled back while wire is being advanced. When wire is completely around it, the jaws are closed and the wire is twisted until the structure is occluded (see FIGS.  34 A- 35 D). 
     Wire Coloring 
     The wire may be colored to make it easier to see in the video monitors used for minimally invasive surgery. The colorings may also be striped so that wire advance can more easily be seen. The wire may also be made with a matte finish to reduce glare and enhance visibility. 
     Wire Coatings 
     The wire can be coated with anti-coagulant materials so that when it is used in vascular procedures it will not promote the formation of clots. To decrease the chances of infection, the wire can be coated with antibiotics. In order to reduce damage and inflammation to the vessel wall due to the presence of the wire, the wire can be coated with an anti-inflammatory agent. The wire may also be coated with a lubricant to facilitate its penetration through tissue. 
     To increase the outer diameter of the wire without making it more stiff, the wire can be coated with a biologically inert material such as Teflon. This would be useful when suturing tissue that is weak or thin because the larger diameter would decrease the stress that the suture places on those tissues. It would also require less torque to twist the ends together than a solid metal wire of comparable size. 
     Shaft That Allows Angled Orientation of Jaw 
     The surgical field often requires that the device access an area that is not in a straight line from the entrance point of the Instrument  662 . One method for doing this with the present device is to give the outer tube  665  of the device shaft a permanent bend θ and allow all the inner tubes  670  (e.g. those that control the jaw, wire cutting, jaw rotation, etc.) to flex through this region. The outer tube of the shaft must be rigid so that the jaw maintains its orientation when it is rotated during wire twisting (see FIGS. 36A-36C and  37 A- 37 C). Another method would be to have the outer tube of the instrument shaft selectively and controllingly flex by additional mechanisms in the instrument such as push/pull elements  675  in a wall  680  of the outer tube of the shaft (see FIGS.  38 A and  38 B). 
     Wire Disposable Details 
     The instrument will use single-use quantities of wire  520  that are sterile and disposable. The disposable consists of a plastic container  685  that contains the wire and a tube  690  that supports wire  520 . Tube  690  projects from the middle of container  685  and is open to the wire reservoir at the proximal end. The disposable is manufactured with wire coiled in the container and fed through the distal end of the tube (see FIGS.  39  and  40 ). To install the disposable, a lever  695  on the instrument is moved displacing one of the drive wheels  700  so that a gap is formed for the insertion of the wire tube. The tube emanating from the container is fed into the back of the instrument so that tube  690  passes between the wheels and all the way up to the jaw where it interfaces with another tube  705  that leads the wire to the jaw surface. The container snaps onto the back end of the instrument. The lever is moved back to the drive position causing the drive wheel to return to the driving position against the wire. 
     The wire tube has a section  710  at the position of the drive wheels that is cut away on both sides to expose the wire to the drive wheel surfaces  700  (see FIGS.  40  and  41 ). This geometric arrangement allows wire  520  to be supported laterally when it is between drive wheels  700 . It also allows the wire to be aligned as it approaches the drive wheels and as it leaves. If the wire entered the mouth of the wire tube after leaving the drive wheels without this lateral support and positioning, slight misalignment between the wire and the wire tube would cause the wire to bend and to potentially buckle. Because the drive wheels hold the wire tightly, misalignment of the wire as it enters the drive wheels will also result in a misalignment between the wire and the tube as the wire is driven to the other side of the drive wheels. The present configuration prevents both of these. 
     Because the wire tube is weak at the cutaway section for the wire, a structure that is connected to the container supports this section of the tube (see FIGS.  39 - 41 ). 
     Lubricious Wire Pathways 
     In order to reduce the forces needed to drive the wire and to increase the amount of force reaching the tip of the wire during tissue penetration, the frictional resistance of the wire moving against the walls of the wire tube can be reduced by using a material with a low coefficient of friction. This is especially important where the wire makes a 90 degree turn from a longitudinal direction along the instrument shaft to a direction that is perpendicular to the jaw surface. Teflon is very lubricious and it can easily be made into tubes with small internal diameters. 
     Wire Drive Wheels With Enhanced Frictional Force Against the Wire 
     Because the contact area of the drive wheel to the wire is very small and a normal force is required to develop a frictional force to thrust the wire, the stresses in the wire can become large enough to permanently deform the wire. If the wire encounters a very hard material that stops its advance, the drive wheel can skid along the surface causing more stresses that can cause further permanent deformations, principally on one side of the wire. These permanent deformations can cause the drive wheel to become stuck in a section of reduced wire diameter such that the wire cannot advance. Also, sections of wire can be created that have unilateral and bilateral radii that can promote premature buckling of the wire either within the instrument or at the site of tissue penetration. To decrease the normal force of the drive wheel against the wire, the coefficient of friction between the two can be increased by treating the surface  715  of the drive wheel  700 A. Examples of such treatments are machining small scratches on the drive wheel surface perpendicular to the direction of wire travel or bead blasting a rough surface onto the drive wheel. Material coatings can also be added to the surface of the drive wheel such as deposition of diamond particles (see FIG.  42 ). 
     Another means of increasing the frictional force is to increase the area of contact between drive wheel  700 A and wire  520 . This could be accomplished by placing a groove  720  into the drive wheel surface that wire  520  can partially fit into so that the drive wheel  700 A also contacts the sides of wire  520 . Also, both wheels  700 A,  700 B could be driven to increase the driving force. Yet another method to increase the surface area between the drive wheel and the wire, is to have multiple drive wheels  725  in series driven by a common or separate linkage (see FIGS.  43 A- 43 C). 
     Jaw Rotational Symmetry 
     After the wire has been passed through the tissue and the wire ends are to be twisted together, it is important that the jaws have rotational symmetry so that while they are rotating they do not scrape or catch the surrounding tissue. 
     Means to Grab Separated Pieces of Tissue 
     Because the tissue pieces  730 A,  730 B to be approximated are often not near each other in the surgical field, it is beneficial for the instrument to bring them together. One or more of the jaw surfaces may have a small tooth or fang  740  that catches the tissue so that the jaw can be left open and moved to the other piece of tissue and positioned such that when the jaw is closed it has grasped both pieces of tissue in an optimized approximation. Wire suturing and twisting proceeds as normal thereafter (see FIGS.  44 A- 44 C). It is also possible for the two sides of the jaw to close independently against a central anvil  745 . Each side of the jaw would grasp a piece of tissue between it and anvil  745  allowing the pieces  730 A,  730 B to be grabbed separately and brought together. The tip of the anvil would have a slit  750  in the middle of the end, open to the distal edge that would allow wire  520  to pass through tissue  730 A,  730 B. After wire  520  had been thus passed, the jaws would be released and pulled away for the steps of grabbing wire  520  and twisting them. Slit  750  in central anvil  745  would allow wire  520  to exit the front end during this step (see FIGS.  45 A- 45 F). 
     Further Modifications 
     It will be appreciated by those skilled in the art that numerous modifications and variations may be made to the above-disclosed embodiments without departing from the spirit and scope of the present invention.