Abstract:
Various forms of a cable fixation device, instrumentation, kit, and methods useful for repairing the skeletal system are introduced. The system utilizes a clamp housing fixing a butt end of a surgical cable therein. In an operative configuration the cable is looped around a damaged bone segment and reentered through a lock aperture in the clamp housing then through a collet and lock cap residing within the lock aperture. The cable loop and each aforementioned component comprise a central axis aligned within a single plane. A sliding interface situated between the lock cap and collet prevent twisting of the surgical cable. The locking mechanism is non-destructive to the cable despite repeated unlocking and relocking of the fixation device. The axis for tensioning of the cable is coincident with the locking axis. A counter torque instrument has a torsional input shaft generally perpendicular to the elongated axis of the instrument.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Provisional Patent Application No. 61/801,837 filed Mar. 15, 2013, the entire disclosure of which is hereby incorporated by reference and relied upon. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to implants and instruments utilized for the fixation of the skeleton, and more particularly to implants and instruments utilizing surgical cable. 
     2. Description of Related Art 
     Surgical wires and cable has a history of use for the repair of the skeletal system. Their usefulness has suffered due to various deficiencies in their function. 
     For example, Kilpela et al. in U.S. Pat. No. 5,415,658 discloses a cable loop connector. When utilizing this connector, the instruments required to tension the cable and lock the cable are situated along two axis&#39;s more than 90 degrees apart. This excessively wide spread between instruments requires a larger incision and increases difficulty in handling. In addition, the locking portion of the connector utilizes an internal crimp making it unuseable for a plurality of locking and unlocking cycles when cable re-adjustments are needed. 
     Mattchen et al. in U.S. Pat. No. 7,207,090 discloses another form of cable retaining device for retaining flexible cables under tension. The device includes a body with an internal tapered void. A wedge shaped plug with recessed edges for containment of a cable is slidable into the void therein locking the cable between the body and plug. During clamping the slidable plug creates friction against the cable member potentially damaging the cable. Due to this, this system is also unsuitable for a plurality of locking and unlocking cycles. 
     Allen et al. discloses in U.S. Pat. No. 7,255,701 various forms of looped cable locking mechanisms. Most embodiments suffer from having each end of the cable loop spaced from each other along the long axis of the bone under repair. The cable within the loop fails to lay in the same plane therein causing a torsional force on the locking mechanism and improper seating on the bone. In addition, the disclosed embodiments have a tensioning axis that is not aligned with the locking axis causing difficulties using instrumentation within a small surgical access space. 
     Justin el al. discloses in U.S. Pat. No. 8,241,288 a collet fixation system for a cable loop and a cable locking instrument. In this bone fixation element, a cable passes through a pair of passageways in which the cable is secured. These passageways are separated by a space along the length of the bone therein once again imparting a torsional force on the fixation element as the cable is tensioned and causing it to not seat properly on the bone. An additional shortcoming is that the collet in this device is threaded. The collet will collapse down and bind the cable as the collet is advanced in rotation causing the cable to be twisted therein imparting unnecessary torsional forces on the cable that could lead to failure. An instrument is disclosed for advancing the collet while stabilizing the fixation element from rotation. Integrated within the C-shaped frame of the instrument is a handle of a collet driver co-aligned with the longitudinal axis of the collet. The positioning of the handle within the frame makes the drive handle both difficult to reach by hand and difficult to impart a hand torsional force. Also, the instrument utilizes a plurality of prongs (6) spaced in a radial pattern to interface with the fixation element. The quantity of prongs and their rounded profile is not well suited for firm control over the fixation element. 
     Several other cabling systems utilize crimps to lock the cable loop in a predetermined cable tension. These systems generally cannot be repeatedly “unlocked” then “relocked” when further adjustments by the surgeon need to be made. 
     BRIEF SUMMARY OF THE INVENTION 
     Disclosed herein is a cable fixation device useful for repairing the skeletal system while overcoming the short comings identified in the surgical cable implant and instrument prior art. The system utilizes a clamp housing that fixes a butt end of a surgical cable within a drum channel located in the clamp housing. In the operative configuration the cable is looped around the bone segment and reentered through a lock aperture in the clamp housing then through a collet and lock cap residing within the lock aperture. The cable loop and each of these forementioned components comprise a central axis situated within a single plane therein preventing any torsion forces on the clamp body that may cause it to cant on the bone. A sliding interface is situated between the lock cap and collet wherein advancing the lock cap does not impart rotation on the collet and twisting of the surgical cable that could otherwise lead to cable failure. In addition, the collet locking mechanism is non-abrasive and otherwise non-destructive to the cable providing the capability to repeatedly unlock and relock the cable without damage to the cable. The axis for tensioning of the cable is generally coincident with the axis on which the lock cap is advanced for locking. This feature simplifies the surgical procedure by eliminating the need for use of a cable tensioner on one axis and the use of a cap locking instrument on a different axis. This reduces the size of incision required to operate the instrumentation therein enabling the surgery to be performed minimally invasively The cable fixation device is also configured for optional assembly during surgery in preferred embodiments. With this feature the cable may be passed in either direction through the cable passer. A specialized counter torque instrument is disclosed having a torsional input shaft at a position 90 degrees to the elongated axis of the instrument. This arrangement offers a tremendous ergonomic improvement to the surgeon attempting lock the cable construct within a surgical site. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       These and other features and advantages of the present invention will become more readily appreciated when considered in connection with the following detailed description and appended drawings, wherein: 
         FIG. 1  is top perspective view of a cable fixation device illustrating only a portion of the cable that will be utilized in the construct; 
         FIG. 2  is cross-sectional view of the cable fixation device illustrated in claim  1  again showing only a portion of the cable; 
         FIG. 3  is a top perspective view of a clamp housing; 
         FIG. 4  is an end view of the clamp housing illustrated in  FIG. 3 ; 
         FIG. 5  is a side view of a clamp housing illustrated in  FIG. 3 ; 
         FIG. 6  is top view of a clamp housing illustrated in  FIG. 3 ; 
         FIG. 7  is an opposing end view of a clamp housing illustrated in  FIG. 3 ; 
         FIG. 8  is a top perspective view of a cable collet; 
         FIG. 9  is a side perspective view of a cable collet illustrated in  FIG. 8 ; 
         FIG. 10  is a bottom perspective view of a cable collet illustrated in  FIG. 8 ; 
         FIG. 11  is a bottom perspective view of a lock cap; 
         FIG. 12  is a top perspective view of a lock cap illustrated in  FIG. 11 . 
         FIG. 13  is a side perspective view of a cannulated driver. 
         FIG. 14  is a side perspective exploded view of a cannulated driver illustrated in  FIG. 13 . 
         FIG. 15  is a close up view of the drive faces of a cannulated driver illustrated in  FIG. 13 . 
         FIG. 16  is a top perspective view of a preferred embodiment of a clamp housing. 
         FIG. 17  is a side view of a preferred embodiment of a clamp housing illustrated in  FIG. 16 . 
         FIG. 18  is a bottom perspective view of a preferred embodiment of a clamp housing illustrated in  FIG. 16 . 
         FIG. 19  is an exploded view of a preferred embodiment of a clamp housing, collet, and lock cap. 
         FIG. 20  is bottom perspective view of a preferred embodiment of a cable collet. 
         FIG. 21  is a side perspective view of a surgical cable assembly. 
         FIG. 22  is a perspective view of a cable drum. 
         FIG. 23  is a close-up perspective view of the butt of the cable and cable drum illustrated in  FIG. 21 . 
         FIG. 24  is a close-up perspective view of the lead of the cable illustrated in  FIG. 21 . 
         FIG. 25  is a perspective view of a preferred embodiment of cable fixation device in a looped configuration. 
         FIG. 25A  is an upper surface view of a preferred embodiment a cable fixation device in a looped configuration. 
         FIG. 26  is a cross sectional view through plane F of a preferred embodiment of the cable fixation device in a looped configuration. 
         FIG. 27  is an exploded perspective view of a preferred embodiment of a counter torque locker instrument. 
         FIG. 27A  is a close-up perspective view of control arms of the counter torque locker illustrated in  FIG. 27 . 
         FIG. 27B  is a cross-sectional view of the clamp base illustrated in  FIG. 27 . 
         FIG. 28  illustrates two perspective views of the internal gear and shaft mechanisms of the counter torque locker illustrated in  FIG. 27 . 
         FIG. 29  is a perspective view of a counter-torque locker mated to a cable fixation device in a looped operative configuration. 
         FIG. 30  is a perspective view of a human femur with a cable passer in position to loop a cable around the bone from a surgical incision site. 
         FIG. 31  is a perspective view of one form of a cable tensioner found in the prior art for tensioning surgical cable prior to locking the implant construct. 
         FIG. 32  is a perspective view of a human femur bone with a cable fixation device in a looped configuration encircling a damaged bone with an attached counter torque locker. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the figures, wherein like numerals indicates like or corresponding parts throughout the several views, numerals of different embodiments are separated by 1000. Similarly, corresponding axes of different embodiments are indicated with a repeated letter. 
     An embodiment of a cable fixation device  100  is illustrated in  FIG. 1 . The device comprises a clamp housing  200 , a cable collet  300 , a lock cap  400 , and a cerclage cable assembly  500 . 
     As illustrated in  FIG. 32 , the cable fixation device  100  is useful during surgery to secure segments of bone together by encircling the cerclage cable assembly  500  around the bone then tensioning and securing the cable. The long axis of the bone is situated generally coaxial with axis E of the loop as illustrated in  FIG. 25 . 
     In one embodiment, cerclage cable assembly  500  ( FIGS. 1 and 2 ) comprises a cable  502  ( FIG. 21 ), a butt  102 , a cable drum  501  ( FIGS. 22 and 23 ), and a cable lead generally indicated at  101  ( FIG. 24 ). The word ‘cable’ used herein may refer to many different elongate tensioning forms. For example, in alternative embodiments cable  502  may be in the form of a wire or line. Each component of the cable fixation device and instruments is made of biocompatible materials typically titanium or stainless steel alloys although polymers such as PEEK may be utilized as well. Cable  502  in preferred embodiments is approximately 1.8 mm in diameter and woven from a blend of titanium or titanium alloy strands for a predetermined blend of flexibility and strength. Cable lead  101  is preferably tapered and formed with a smooth surface to keep all cable strands tightly wound for eased entry into cable apertures or channels of housing  200  and through instruments and to prevent injury to the patient or surgeon. For example, lead  101  may be swaged. 
     The butt  102  opposes lead  101  ( FIG. 21 ) on cable  502  and comprises the cable end configured for anchoring within clamp housing  200 . In preferred embodiments the butt  102  ( FIG. 23 ) comprises an enlarged terminal portion illustrated here in the form of a cable drum  501  pressed on the cable. The drum  501  comprises a cylindrical sleeve with one or more entry faces  103  that are tapered or radiused. The clamp wall  104  diameter of drum  501  is sized to impart sufficient friction at the cable surface to prevent being pulled off due to tensioning of cable  502  or due to other forces imparted by the patient&#39;s skeletal system. Other methods may be used to secure drum  501  on cable  502  and may include for example welding, crimping, or molding. In alternate embodiments the butt may take other forms such as simply the cut end of the cable wherein a portion of the clamp housing is crimped on the cable. 
     Each component of the cable fixation device  100  partially resides within clamp housing  200 . As seen in  FIGS. 3-7 , the housing  200  comprises a block body generally indicated at  218 . Formed on body  218  is a pair of opposing side surfaces  208 , a front end or leading surface  209 , a rear end surface or trailing surface  211 , an upper surface  207 , and a bottom surface  216 . 
     To assist in proper fit of housing  200  on the bone surface, the bottom surface  216  is concave as generally indicated at  217  of  FIG. 5 . In this embodiment, the radius of the concave is less than the radius of the bone surface onto which it will be seated. Further in this embodiment, bottom surface  216  is concave between opposing side surfaces  208  as generally indicated at  214  of  FIG. 4 . 
     Together, the concave surface at  217  and  214  define feet  215  at each corner of bottom surface  216  of body  218 . These feet  215  may be sharpened or extended into the form of teeth in some embodiments and may penetrate the bone surface to prevent slippage of the clamp housing  200  across the outer surface of the bone when cable fixation device is in an operative configuration wherein cable  502  is secured in a loop around the bone segments with cable tensioned and secured to a pre-determined tension utilizing lock cap  400  advanced on cable collet  300 . 
     Extending into the trailing surface  211  of body  218  along axis ‘A’ is a drum channel generally shown at  212 . Drum channel  212  defines drum wall  205 . Drum channel  212  is shaped and sized to house cable drum  501  ( FIG. 2, 22 ) of cerclage cable assembly  500 . Cable shelf  219  with drum stop surface  220  ( FIG. 6 ) contain drum  501  in drum channel  212  preventing it from being pulled out of housing  200  when the cable  502  is tensioned. Cable slot generally indicated at  213  provides for the loading of cable  502  into drum channel  212  then provides for seating of the cable drum  501  into the drum channel  212  upon pulling of the free end of cable  502 . In alternative embodiments, the butt  102  of cable  502  is secured in housing  200  by way of methods described earlier. 
     A lock aperture generally shown at  203  ( FIGS. 2 &amp; 3 ) is defined by a series of walls with various diameters. Passage wall  201  is sized in diameter to freely pass cable  502 , the cable collet  300 , and the lock cap  400 . Step  210  transitions between passage wall  201  and fixation wall  202 . Fixation wall  202  comprises features to fix the lock cap  400  in place. In this embodiment these fixation features are in the form of threads (not shown) formed in the surface of fixation wall  202  for co-engagement with threads (not shown) formed in fixation face  406  of lock cap  400  ( FIG. 11 ). Alternatively, other co-engagement configurations may be utilized for fixation between the lock cap and clamp housing such as for example a bayonet connection. 
     Compression wall  204  ( FIG. 2, 3,7 ) is tapered and complements lock wall  305  ( FIG. 8-9 ) of cable collet  300  wherein when lock cap  400  is advanced along axis B, lock wall  305  is also driven causing collet  300  to compress and clamp on cable  502  thereby fixing cable in place. Inlet wall  206  ( FIG. 4 ) is sized sufficiently large to freely pass cable  502  while small enough to prevent passage of collet  300 . In alternative embodiments, compression wall  204  may assume other forms such as a smaller diameter step to serve a similar function of compressing collet. 
     Cable collet  300  is illustrated in  FIGS. 8-10 . In this embodiment, the collet  300  comprises a curved body  311  with clamp surface  301  extending therethrough along axis ‘C’. Clamp surface  301  defines central aperture  306  sized sufficient in diameter to pass cable  502 . Formed in curved body  311  is a bottom face  307 , a top face  303 , a lock wall  305 , and a head face  302 . The curved body  311  may comprise one or more tapered face  304 . Extending from the top face  303  are a plurality of top compression gaps  309  and extending from the bottom face  307  are bottom compression gaps  308 . These gaps  308  and  309  are defined by gap walls  310 . In this embodiment the gaps are cut linear along axis C and the gaps  308  radially alternate with gaps  309 . In alternate embodiments these gaps may take other forms such as a spiral. At the bottom of each gap is a resilient wall  312  which flexes therein providing for central aperture  306  to reduce in diameter for cable clamping. In alternative embodiments collet  300  may be spherical. 
     Lock cap  400  ( FIG. 11-12 ) comprises a cylindrical body  410  with central aperture  401  extending along axis D. Drive surfaces  407  define drive pocket  408  which extend into cylindrical body  410  from top surface  411 . Drive pocket  408  is configured in shape to receive cannulated driver tip  602  ( FIG. 15 ). At the bottom of drive pocket  408  is pocket base  409 . Cable wall  402  defines central aperture  401 . Aperture  401  has sufficient diameter to pass cable  502  through drive wall  412 . Fixation face  406  engages fixation wall  202  of clamp housing  200  for locking. In this embodiment, fixation face  406  is threaded as is wall  202  (threads not shown). Threads on face  406  may include a lead in taper  405  to ease starting of threads. Step  404  decreases diameter of drive wall  412  to prevent interference with threads during assembly. 
     In preferred embodiments, drive wall  412  drives with sliding engagement against top face  303  of collet  300  during locking. Due to this sliding engagement, a rotation of the lock cap  400  does not cause rotation of the collet  300  and therefore cannot induce rotation between clamp surface  1301  and cable  1502 . In addition, the sliding engagement between lock cap  400  and collet  300  provides for pushing of the collet  300  linearly along axis C such that clamp surface  301  slides along the cable until the collet collapses down therein locking cable  1502  in place. In the preferred embodiments illustrated in  FIGS. 8, 9, and 11 , top face  303  and drive wall  412  are orientated generally perpendicular to the central apertures  306 ,  401  which extend through the collet  300  and lock cap  400 . As illustrated in  FIGS. 19 and 26 , the long axis of the cable passes through these central apertures along Axis BB. Therefore, in these embodiments the sliding engagement between top face  303  and drive wall  412  occurs in a plane generally perpendicular to the long axis of the cable. 
     As an alternative, lock cap  400  and collet  300  may be unitary wherein rotation of lock cap  400  will cause 1:1 rotation of the collet  300 . This approach is less preferred and is noted in the prior art. Here, the clamp surfaces within the collet induce a twist on the cable  502  as the collet  300  tightens around it that can lead to abrasion and fraying of the cable. In addition, the cable surface has inherent irregularities which become bound in the collet prematurely therein causing the cable to be pushed distally during locking and leading to an undesired reduction in cable cerclage tension. 
       FIGS. 13-15  illustrate cannulated driver  600 . This instrument is used to advance lock cap  400 . The driver  600  comprises a drive shaft  603  with central cable aperture  601  extending the length of the instrument for passage of cable  502 . At the distal end of drive shaft  603  is driver tip  602  with drive faces  609  configured to be received in drive pocket  408 . Drive faces  609  will transmit torsional forces applied by the user at the handle  605  into drive surfaces  407  in the lock cap for advancement toward collet  300  for locking or away from collet for unlocking. Distal stop surface  608  and proximal stop surface  610  are advanced in to drive pocket  408  until seated against top surface  411  or pocket base  409 . Drive shaft  603  may be configured as a singular shaft extending through handle  605  or as illustrated may be configured in segments to include proximal shaft  612 . In this configuration, each shaft comprises fixation bosses  604  and  606  to seat within and assemble within handle  605 . One or more fixation holes  613  may house pins or screws holding handle to drive shaft  603 . Located at the proximal end of proximal shaft  612  is tensioner face  611  for interfacing with a tensioner instrument. 
       FIGS. 16-18  illustrates a preferred alternative clamp housing  1200  comprising many of the same features of clamp housing  200 . Again, corresponding parts are offset by 1000. For example, opposing side surfaces  208  on clamp housing  200  are identified as opposing side surfaces  1208  on the clamp housing  1200 . 
     Extending into each opposing side surface  1208  is a pair of opposed control slots  1228  traveling parallel yet offset from axis BB. Control slots  1228  house control tabs  708  extending from clamp base  701  ( FIG. 27 ). Control slots  1228  are bounded by opposed upper tilt wall  1225  and lower tilt wall  1226  and medially by steering wall  1227 . Projecting from bottom surface  1216  are a plurality of teeth  1229  illustrated here in the form of elongated sharps  1230  extending between opposing side surfaces  1208 . The concave curvature shown at  1217  of bottom surface  1216  remains in this embodiment, however concave surface  214  illustrated in  FIG. 4  is absent. The elongate sharps  1230  and bottom surface  1216  are generally linear between opposing side surfaces  1208  as illustrated in  FIG. 18 . 
       FIG. 20  illustrates an alternative collet  1300  having ⅓ rd  less bottom compression gaps  1308  and top compression gaps  1309 . In this embodiment, rather than terminating in a squared corner, each compression gap terminates in a rounded corner to improve flexibility and prevent stress concentrations. In some embodiments these rounded corners are formed by EDM machining. 
       FIG. 25  illustrates cable fixation device  1100  with cerclage cable assembly  1500  formed into a loop as if wrapped around bone segments. As in previous embodiments, the cerclage cable assembly  1500  resides in a single plane here shown as plane F and generally perpendicular to axis E. This single plane alignment is further illustrated in  FIG. 25A  and is responsible for the absence of torsional forces on the clamp housing  200  that may cause it to cant on the bone when cable  1502  is tensioned and locked in the operative configuration. On competing devices wherein the cable loop is not aligned in a single plane, the instrumentation utilized to hold the clamp housing during insertion to the surgical site and during tensioning and locking will counteract torsional forces on the clamp housing to keep the housing aligned. However, the clamp housing will cant on the bone causing a loss in cable tension as soon as the instrumentation is removed. This leads to a reduction in the stability provided by the cable and clamp construct. Illustrated in  FIG. 26  is a cross section of cable fixation device  1100  through plane F also illustrating the internal components of the assembly having a co-planar elongate axis. 
     As noted earlier, some embodiments of the clamp housing include control slots for attachment of a counter torque locker. A preferred embodiment of a counter torque locker  700  is illustrated in  FIG. 29  with attached cerclage cable assembly  1500 .  FIG. 27  illustrates an exploded view of counter torque locker  700  for viewing of internal parts. Clamp base  701  serves to contain several parts of the assembly. Worm rod  702  is situated generally perpendicular within the proximal end of clamp base  701  and is generally co-axial with axis H. Worm shaft  703  is situated generally co-axial with axis G within clamp base  701 . Hat  704  is situated within the proximal portion of clamp base  701  and is also generally co-axial with axis G. Worm retainer  705  is generally co-axial with axis H as is drive bar  706 . 
     A cross sectional view of clamp base  701  is illustrated in  FIG. 27B . Control arm  715  extends from base  701  at the distal end. Opposing containment walls  707  are spaced to house opposing side surfaces  208  of clamp housing  200  therebetween. Control tabs  708  extend parallel to axis G and are sized and positioned to fit in control slots  1228  of clamp housing  1200 . The control tabs  708  comprise mating walls positioned to mirror with the upper tilt wall  1225 , lower tilt wall  1226  and steering wall  1227  of clamp housing  1200 . These mating walls are the upper mirror  709 , lower mirror  710 , and steering mirror  711 . Proximal to control arms  715  is stop wall  712  situated to abut clamp housing  200  when the clamp base  701  is fully engaged with it and lock cap  1400  is fully advanced to locking. 
     Clamp base  701  comprises an internally positioned shaft guide  713  extending down the length of base  701  sized to house worm shaft  703  therein. Along axis H, worm guide  714  extends through a proximal portion of clamp base  701 . At the proximal end of clamp base  701  resides hat seat  717  for seating hat  704  thereagainst. Inset the proximal end of clamp base  701  is hat guide  716  sized and shaped to house hat  704  therein. 
       FIG. 28  illustrates the internal gear mechanisms. Worm rod  702  resides within worm guide  714  and rotates freely therein. Worm shaft  703  resides within shaft guide  713  and also rotates freely therein. The worm rod  702  comprises a worm helix  721  (shown in location only) on its outer surface for functioning as a worm drive. The worm rod  702  comprises a worm shoulder  725  for securing the worm drive against one of the worm walls  718 . A worm retainer  705  is removably positioned on worm rod  702  opposite the worm shoulder  725  to secure the worm rod  702  in a predetermined position within clamp base  701 . Interior to worm shaft  703  is cannula  724  which extends the entire length along axis G and is sized to pass cable  502 . At the distal end of worm shaft  703  is drive boss  723  with complementing surfaces for residing within drive pocket  1408  and transmitting torsional forces to drive surfaces  407  to advance lock cap  400 . Alternatively, worm shaft  703  may be configured with a drive bit detachable from worm shaft  703  such that the drive bit is replaceable as it wears. In one form this drive bit will be backed by a spring biasing the drive bit distally such that as lock cap  1400  is advanced distally the drive bit will stay entirely engaged in the drive pocket  408 . At the proximal end of worm shaft  703  are radially placed worm teeth  722  (shown in location only) shaped to inter-digitate or otherwise mesh with the worm helix  721  formed on worm rod  702  to provide a worm and worm gear relationship. 
     Hat  704  comprises a hat base  726  sized for secure fit within hat guide  716  of clamp base  701  and positioned by hat lip  728  abutting hat seat  717 . Hat tunnel  727  extends through hat  704  along axis G and is sized for passing cable  502  therethrough. Hat pod  720  provides a proximal surface against which a distal end of a cable tensioning instrument ( FIG. 31 ) may be placed. 
     Drive bar  706  comprises internal drive surfaces (not shown) for acting on complementing worm drive  719  surfaces of worm rod  702 . Torsional forces imparted by the user on drive bar  706  causes rotation of the worm rod  702 . These forces are imparted through the worm helix  721  to worm teeth  722  therein causing the drive boss  723  to advance lock cap  1400  in a direction that will cause either tightening or loosening of collet  1300  around cable  1502 . 
     The instruments disclosed for tensioning cable  1502  and advancing lock cap  1400  are generally co-aligned along axis B during operation. This feature simplifies the surgical procedure by eliminating the need for handling of a cable tensioner positioned on one axis and the use of a cap locking instrument on a different axis. This co-alignment also provides a minimally invasive approach for completing the surgery as it reduces the size of incision required to operate the instrumentation. In addition, the cable fixation device  100  disclosed herein utilizing the collet  300  and lock cap  400  fixes the cable  502  at the tension applied by the tensioner without loss of tension. 
     The cable fixation device  100  will preferably be packaged pre-assembled with collet  300  loosely seated within compression walls  204  and lock cap  400  loosely threaded within fixation wall  202 . The cable drum  501  is pre-seated within drum walls  205 . A surgical kit may be provided for use in the surgical suite comprising the cable fixation device, the cannulated driver, the counter torque locker, a cable passer, and a cable tensioner. 
     The cable fixation device  100  is utilized by passing the free end of the cable around the bone or bone segments to be stabilized. A cable passer  800  ( FIG. 30 ) may be utilized for this purpose. The passer typically comprises a passer handle  802  connected to a passer shaft  803  for guiding a semi-circular passer tube  801  around the outer surface of the bone. The surgical cable is fed into the passer tube  801  until exposed out the other side. The passer  800  may then be removed leaving the cable  1502  encircled around the bone. The lead  1101  of cable  1502  is then fed through inlet wall  1206  of clamp housing  1200 , through the central aperture  1306  of the collet  1300 , and through the cable wall  1402  of lock cap  1400 . In an optional provisional locking step, the surgeon may choose to use cannulated driver  600  ( FIG. 13 ) to temporarily secure the cable. In this event, the cable lead  1100  is fed through central cable aperture  601  of driver tip  602  until the lead  1101  exits tensioner face  611 . The driver tip  602  is then seated in drive pocket  1408 . Grasping the cable lead, the surgeon snugs the cable to a desired cable tension then applies hand torque on handle  605  to advance lock  1400  until cable collet  1300  compresses around cable  1502  to secure the loop. The surgeon may choose to move on to secure other cables before returning to perform final locking. In preferred methods, driver  600  is then removed and replaced with counter torque locker  700 . The cable lead  1100  is fed though cannula  724  of worm shaft  703  until lead  1101  exits hat tunnel  727 . Drive boss  723  of counter torque locker  700  is seated in drive pocket  1408  and control tabs  708  are seated within control slots  1228  of clamp housing  1200 . The lead  1101  of the cable  1502  is then fed into a standard surgical cable tensioner ( FIG. 31 ). The counter torque locker  700  is used to loosen lock cap  1400  and the cable is tensioned to a predetermined tension therein causing the cerclage loop around the bone to tighten and elongated sharps  1230  to engage the bone surface. The surgeon then applies torque to drive bar  706  therein causing rotation of worm rod  702 , worm shaft  703 , and final advancement of lock cap  1400  therein forcing collet  1300  to collapse about cable  1502  securing the cable fixation device  100  at a predetermined cable tension. If the surgeon chooses, drive bar  706  or handle  605  may be derotated to loosen and remove the cable fixation device  100 ,  1100  or to retension to an alternative tension level before relocking without damage to cable  502 ,  1502 . The tensioner and counter torque locker  700  may then be removed and excess cable lead trimmed. 
     In an alternative method, portions of the cable fixation device  100  may be assembled during surgery. In preferred embodiments the butt of the cable is configured in size to be passable through the cable passer then assembled with the clamp housing  200  after the passer instrument is removed. This feature provides for the cable  1502  to be passed in either direction through passer tube  801 . In cases where introducing the passer instrument from one side of the bone is easier than the other, the surgeon may be forced with prior art systems to introduce the passer from the more difficult side to assure the clamp housing  200  is positioned in a convenient direction for tensioning and locking. This assembled in surgery feature ensures the surgeon will be able to enjoy the convenience of introducing the passer instrument around the bone from either entry position while also being assured the clamp housing will be directed in a convenient direction for tensioning and locking. Assembly in preferred embodiments is completed by passing the cable around the bone then dropping cable  1502  through cable slot  1213 . Cable  1502  is pulled until cable drum  1501  is seated in drum channel  1212  and against drum stop surface  1220 . This assembly during surgery feature is made possible by cable slot  1213  as it provides a path for cable drum  1501  to be seated in drum channel  1212  without requiring the cable lead  1101  to pass through the drum channel  1212  first. 
     In an alternative method, the provisional lock step using driver  600  is not performed. Once the cable is passed around the bone and through the clamp housing, the surgeon may immediately use the counter torque locker  700 , with cable tensioner if she so chooses, to perform provisional or final locking. 
     In another alternative method, the surgeon may choose not to use a counter torque locker  700  when it is believed sufficient final locking can be achieved without it. In this method the surgeon may choose to use driver  600  with clamp housing  200  or  1200  to achieve final locking. Driver  600  may also be used with a cable tensioning device. 
     The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and fall within the scope of the invention.