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 head 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 multi-part collet and lock cap residing within a 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 cerclage inserter instrument is disclosed.

Description:
[0001]    This application is a Continuation-In-Part application claiming priority to pending Non-Provisional patent application Ser. No. 14/216,913 filed on Mar. 17, 2014 which claims the benefit to now expired Provisional Patent Application No. 61/801,837 filed on Mar. 15, 2013. This application also claims priority to pending Provisional Patent Application No. 62/192,301 filed on Jul. 14, 2015. This application is also related to PCT Application No. WO2014145979, filed Mar. 17, 2014, pending European Application 14763374.7 filed Oct. 14, 2015, and pending Canadian Application No. 2,907,345 filed Sep. 15, 2015. The entire disclosure of each of these applications is hereby incorporated by reference and relied upon. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The invention relates generally to surgical implants and instruments, and more particularly to surgical tensioning lines such as surgical cable, devices for fixation of surgical cable during surgery, and related instruments and methods. 
         [0004]    Surgical cable is used by orthopedic surgeons in a variety of surgical applications but primarily for the stabilization of bone and bone segments. For example, in an open heart surgery procedure, the sternum is cut into two halves and each half is retracted to access the heart. Following the surgical repairs to the heart, the sternum is often rejoined using surgical cable looped around the two halves of the sternum, the loop is tensioned then fixated therein providing the stability required for the two halves of the bone to fuse. 
         [0005]    Surgical cable may also be used to secure individual vertebral body segments to an elongated spinous rod for stabilization after spinal fracture or in an effort to correct a spinal deformity. Surgical cable is also effective at stabilizing fractures in long bones of the extremities such as in the femur. In these cases the cable is looped, also known as cerclaged, around the bone through a bone plate or a crimp, tightened to a specified tension with a tensioner tool, and then locked with a cable crimp or screw biting down on a crimp to clamp the cable. 
         [0006]    Although effective in many cases, these methods can be improved. Commonly the cable tensioner and the screw that locks down on the crimp are separated by an angle thereby necessitating the operation of two spaced instruments at once in a small surgical space. Also, repairing a fracture may require sequentially tensioning several different cables at a provisional tension and then returning for a final tensioning. This method typically requires the use of a ‘retensioner’ instrument on each cable used at the front of a tensioning instrument to maintain tension in the cable while the tensioning instrument is moved to the cable to be tightened. This method, albeit cumbersome, eliminates the need to deform the crimp during a provisional step which may cause damage to the cable or crimp. 
         [0007]    Description of Related Art 
         [0008]    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. 
         [0009]    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. 
         [0010]    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. 
         [0011]    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. 
         [0012]    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. 
         [0013]    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. 
         [0014]    What is needed are improved cerclage cable implants and corresponding instruments configured for eased insertion and robust performance. The needed improvements include a reduction of the number of instruments required to complete the surgical procedure, a reduction in the number of instruments used within the incision at the same time, and providing easy provisional cable locking and unlocking to provide the surgeon repeated cable adjustment without detrimental surgical consequences. It is also desirable that provisional cable locking and unlocking systems fully lock and unlock. In the unlocked position the cable must move freely without binding through the locking component providing for easy readjustment of tension and implant position. It is also desirable that the locking component on the cable applies generally uniform force across the cable to improve fixation while reducing the potential for cable damage. Also desirable are instruments that restrain implants to the instruments without fear of unintended fall off in the surgical corridor while providing prompt release of the implant at the completion of the surgical procedure. 
       SUMMARY OF THE INVENTION 
       [0015]    Disclosed herein are improved implants, instruments, and methods of use of novel cable fixation devices and associated cerclage insertion instruments useful for repairing the skeletal system while overcoming the short comings identified in the surgical cable implant and instrument prior art. In accordance with one form of the article of invention, the clamping mechanism of the implant utilizes a multi-part (segmented) tapered collet that encircles the cable and is driven into a clamp body by a cannulated lock cap once a predetermined cable tension is established through the cable. 
         [0016]    In some forms a multi-part collet is tapered on opposed ends of a collet to facilitate well distributed clamping pressure on a surgical cable through the entire length of a collet. Utilizing a cable fixation device with multi-part collet, a cable can be repeatedly locked and unlocked without damaging the cable or other portions of the cable fixation device. 
         [0017]    In some forms, a system utilizes a clamp housing that fixes an enlarged head of a surgical cable within a head aperture located in the clamp housing. 
         [0018]    In some forms, in an operative configuration the cable is looped around a bone segment using a surgical cable passer and reentered through a lock aperture in a clamp housing then through a collet and lock cap residing within the lock aperture. The cable cerclage loop and each of these aforementioned components share a collinear central axis situated within a single plane within a clamp housing therein preventing any torsion forces on the clamp body that may cause clamp housing to cant on a bone during tensioning and eliminating instrument handling difficulties and larger footprint associated with using a plurality of non-aligned instruments concurrently within a surgical corridor. 
         [0019]    In some forms, sliding engagement is imparted between opposed faces on a lock cap and collets wherein advancing the lock cap does not impart rotation on the collet nor twist a surgical cable that could otherwise lead to cable failure. 
         [0020]    In some forms a 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. 
         [0021]    In some forms a cable fixation device is also configured for optional assembly during surgery in preferred embodiments. With this feature a cable may be passed in either direction through a cable passer. 
         [0022]    In some forms a lock cap and housing of a cable fixation device comprise complementing frictional engagment features to prevent unintended back out and loosening of the locking cap. In preferred embodiments these complementing features are in the form of interfering features disposed on the lock cap and in some forms also on the housing of a fixation device. 
         [0023]    Disclosed further are various embodiments of a cerclage insertion instrument. 
         [0024]    In some forms, a cable fixation assembly may be loaded into or released from a clasp portion of a cerclage insertion instrument from a direction angled or preferably normal to the long axis of the instrument. 
         [0025]    In some forms a clasp activator mechanism causes deflectable frame legs to deflect outward in a release configuration to provide for loading or release of a clamp housing in a clamp window. 
         [0026]    In some forms a clasp activator mechanism causes deflectable frame legs to be locked to a predetermined clamp window width therein restraining a clamp housing between a pair of clamp arms. 
         [0027]    In some forms restraint ribs (control arms) extending from opposing arm faces occupy control slots on a clamp housing. 
         [0028]    In some forms restraint ribs are orientated perpendicular to a long axis of a frame body of a cerclage inserter instrument. 
         [0029]    In some forms a clasp activator mechanism activates movement of a ram to cause deflection of frame legs. 
         [0030]    In some forms a ram rides against a deflection cam to cause deflection of frame legs. 
         [0031]    In some forms a ram comprises a pod channel for capture of a pod associated with frame legs to limit deflection thereof. 
         [0032]    In some forms a ram is capable of linear axial movement when seated within an inserter frame of a cerclage inserter instrument. 
         [0033]    In some forms a lock driver is disposed in a ram and the ram is disposed within an inserter frame wherein each component share a common elongate axis. 
         [0034]    In some forms a ram component comprises a pivot bore at a proximal end for axial control of the ram. 
         [0035]    In some forms a clasp activator mechanism comprises a lever mechanism articulating from a fixed pivot pin extending from an inserter frame. 
         [0036]    In some forms a clasp activator comprises a lever mechanism articulating from a fixed pivot pin to drive a lever pin disposed in a ram. 
         [0037]    In some forms a ram component comprises one or more ram horns extending from a distal end for control of a pair of deflectable frame legs. 
         [0038]    In some forms, a ram component comprises a central aperture for occupation by a lock driver component. 
         [0039]    In some forms, an inserter frame component comprises a near window for housing a provisional lock cap driver portion. 
         [0040]    In some forms, an inserter frame component comprises a control mount on a proximal end for securing a control portion thereto. 
         [0041]    In some forms a biased button or lever may be used to release the axial position of a lock driver. 
         [0042]    In some forms a thumb wheel or cup may be used by a user to provide provisional locking of a lock cap in a cable fixation construct. 
         [0043]    In some forms a control handle is releasably connected at a distal end of an inserter frame. 
         [0044]    In some forms a control handle comprises a primary bevel gear and a complementing secondary bevel gear housed within. 
         [0045]    In some forms said primary bevel gear is coupled to a lock driver. 
         [0046]    In some forms said secondary bevel gear is coupled to a drive coupler. 
         [0047]    In some forms said secondary bevel gear resides in a secondary bevel gear pocket of said control handle. 
         [0048]    In some forms said primary bevel gear resides in a distal portion of a control pocket formed within said control handle. 
         [0049]    In some forms a distal portion of said control pocket is threaded. 
         [0050]    In some forms said control portion comprises a bearing and bearing race. 
         [0051]    In some forms an outer radial wall of said bearing race is threaded. 
         [0052]    In some forms threads on said bearing race complement said threads in distal portion of said control pocket for threaded engagment. 
         [0053]    In some forms a torsion wrench engaged generally perpendicular to the long axis of a cerclage inserter instrument is used to impart torsional forces through a drive coupler, a bevel gear set, a lock driver, to a locking cap of a surgical cable fixation device. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0054]    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: 
           [0055]      FIG. 1  is a perspective view of one form of a cable fixation device ; 
           [0056]      FIG. 2  is a close up perspective view of the locking portion of one form of a cable fixation device; 
           [0057]      FIG. 3  is a perspective view of a cable fixation device illustrated in  FIG. 2  with clamp housing removed; 
           [0058]      FIG. 4  is a side view of one form of a cable fixation device as illustrated in  FIG. 2  with exploded locking cap and collet; 
           [0059]      FIG. 5  is a top perspective view of a cable fixation device illustrated in  FIG. 2  with exploded locking cap and collet; 
           [0060]      FIG. 6  is a bottom perspective view of a cable fixation device illustrated in  FIG. 2 ; 
           [0061]      FIG. 7  is a side semitransparent view of a cable fixation device illustrated in  2 ; 
           [0062]      FIG. 8  is a top perspective view of a cable fixation device illustrated in  FIG. 2  with locking cap removed; 
           [0063]      FIG. 9  is a front perspective view of a cable fixation device illustrated in  FIG. 2  with cable removed; 
           [0064]      FIG. 10  is a top perspective view of a housing of the cable fixation device illustrated in  FIG. 2 ; 
           [0065]      FIG. 11  is a top view of a housing of a cable fixation device illustrated in  FIG. 2 ; 
           [0066]      FIG. 12  is front perspective view of a housing of the cable fixation device illustrated in  FIG. 2 ; 
           [0067]      FIG. 13  is top perspective view of a housing of the cable fixation device illustrated in  FIG. 2 ; 
           [0068]      FIG. 14  is a side view of one form of a locking cap to illustrate threads; 
           [0069]      FIG. 15  is a top perspective view of a locking cap illustrated in  FIG. 9 ; 
           [0070]      FIG. 15A  is a top perspective view of an alternative form of a locking cap; 
           [0071]      FIG. 16  is a bottom perspective view of a locking cap illustrated in  FIG. 9 ; 
           [0072]      FIG. 17  is a top view of a locking cap illustrated in  FIG. 9 ; 
           [0073]      FIG. 18  is a perspective view of one form of a multipart collet; 
           [0074]      FIG. 19  is a side view of one form of a multipart collet; 
           [0075]      FIG. 19A  is a top perspective view of one form of one section of a multipart collet; 
           [0076]      FIG. 20  is a top perspective view of one form of a locking cap pre-assembled with a housing of a cable fixation device; 
           [0077]      FIG. 21  is a cross-sectional view across plane E-E of one form of cable fixation device in an operative configuration; 
           [0078]      FIG. 22  is a cross-sectional view across plane F-F of one form of a cable fixation device as a locking cap is partially advanced into a housing; 
           [0079]      FIG. 23  is a cross-sectional view across plane F-F of one form of a cable fixation device as a locking cap is nearly fully advanced into a housing and illustrating an interference fit between to lock cap and housing to prevent lock cap backout; 
           [0080]      FIG. 24  is a top perspective view of a cerclage insertion device clasping a cable lock and a portion of a cable implant; 
           [0081]      FIG. 25  is side perspective view of a cerclage insertion device clasping a cable lock and a portion of a cable implant; 
           [0082]      FIG. 25A  is a close up perspective view of a cable fixation device preparing to be clasped by a cerclage insertion device; 
           [0083]      FIG. 26  is a top perspective view of one embodiment of a cable implant inserter construct illustrating a torsion wrench engaged for advancing lock driver  702 ; 
           [0084]      FIG. 26A  is a side view of a distal end portion of a cerclage inserter instrument illustrating the interaction between a ram and inserter frame portion; 
           [0085]      FIG. 27  is an exploded view of a preferred embodiment of a cerclage inserter instrument; 
           [0086]      FIG. 27A  is a top perspective view of a preferred embodiment of a clasp activator; 
           [0087]      FIG. 27B  is a side view of the cerclage inserter of  FIG. 27  with internal components exposed by displacement of outer components; 
           [0088]      FIG. 27C  is a perspective view of a preferred embodiment of a thumb cup; 
           [0089]      FIG. 27D  is a cross sectional view through a mid-plane of a drive coupler; 
           [0090]      FIG. 28  is a perspective view of a preferred embodiment of a lock driver; 
           [0091]      FIG. 29  is a side view of a preferred embodiment of a ram; 
           [0092]      FIG. 30  is a perspective view of ram illustrated in  FIG. 29 ; 
           [0093]      FIG. 31  is a side view of a preferred embodiment of a inserter frame; 
           [0094]      FIG. 32  is a perspective view of an inserter frame illustrated in  FIG. 31 ; 
           [0095]      FIG. 32A  is a proximal end view of an inserter frame illustrated in  FIG. 31 ; 
           [0096]      FIG. 33  is a proximal perspective view of a preferred embodiment of a control handle which houses internally several components of a control portion; 
           [0097]      FIG. 34  is a distal perspective view of a control handle illustrated in  FIG. 33 ; 
           [0098]      FIG. 35  is a distal view of a control handle illustrated in  FIG. 33 ; 
           [0099]      FIG. 36  is a proximal view of a control handle illustrated in  FIG. 33 ; 
           [0100]      FIG. 37  is perspective view of a partially disassembled cerclage inserter instrument for cleaning purposes; 
           [0101]      FIG. 38  is a perspective view of a portion of an instrument disassembly button with parts removed 
           [0102]      FIG. 39  is a cross-sectional view through plane E of a surgical cable cerclage encircling a long bone, passing through a fixation assembly in preparation for tensioning by a cable tensioner and fixation by action of a cerclage inserter instrument. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0103]    Referring to the Figures and written description, several exemplary embodiments of cable fixation devices, related instruments, and of methods of use thereof are disclosed herein. 
         [0104]    In a preferred embodiment, one form of a cable fixation device  100  is illustrated in  FIGS. 1-7 . A cable fixation device  100  comprises a fixation assembly portion  102  and a cerclage cable  500  portion. A fixation assembly portion  102  comprises a clamp housing  200  portion, a cable collet  300  portion, and a lock cap  400  portion also referred to as a lock. 
         [0105]    Each component of a cable fixation device  100  partially or fully resides within clamp housing  200 . One end of cerclage cable  500  is enlarged as a cable head  504  and resides within clamp housing  200  in an operative configuration. In preferred embodiments, the cable head  504  is removable from clamp housing  200 . In this embodiment ( FIG. 3 , shown without clamp housing), enlarged cable head  504  is in the form of a drum  501  fixed to the cable  502  end by friction, crimping, weld, or other methods. 
         [0106]    As illustrated in  FIGS. 4-13 , clamp housing  200  comprises a block body  218  having a concave shaped  217  bottom surface  216  extending from a first side surface  208 A to an opposed second side surface  208 B. Concave shape  217  preferably has a concave radius slightly smaller than a bone surface it will be seated on. In alternative embodiments, concave shape  217  may be a generally flat surface extending between elevated opposing feet. Block body  218  comprises a front end surface  211  and a rear end surface  209 . Protruding adjacent the junction of front end surface  211  and bottom surface  216  is one or more first feet  215 A. Protruding adjacent the junction of the rear end surface  209  and bottom surface  216  is one or more second feet  215 B. In some embodiments, first and second feet may be sharpened or extended into the form of teeth and serve to prevent slippage across the surface of a bone once implanted on bone and cable tensioned. 
         [0107]    Extending towards front surface  211  of body  218  along axis ‘A’ ( FIG. 9, 11 ) is head aperture  212  defining head walls  205  sized to house cable head  504  which here is in the form of a cable drum  501  of cable  500 . Cable shelf  219  with head stop surface  220  contain drum  501  in head aperture  212  and prevent it from being pulled out of the housing when the cable  502  is tensioned. Cable slot  213  is sufficiently wide for the loading of cable  502  into head aperture  212  wherein the cable drum  501  is then seated in head aperture  212  upon pulling of the free end of cable  500 . 
         [0108]    Lock aperture  203  defines a series of walls with surfaces having various diameters as illustrated in  FIGS. 5 and 10 . Passage wall  201  is sized of sufficient diameter to freely pass cable  502 , cable collet  300 , and lock cap  400 . A step  210  draws in to fixation wall  202 . Fixation wall  202  comprises features to fix lock cap  400  in place and in this embodiment is in the form of threads for engagement with threads on opposed cap fixation wall  406  of lock cap  400 . Compression wall  204  is tapered or may be stepped and complements second lock wall  305 B ( FIG. 18 ) of collet  300  wherein when lock cap  400  is threadably advanced, lock wall  305 B is driven along axis C therein causing each component of collet  300  to move towards each other to clamp against and fix cable  502  in place within clamp housing  200 . Formed within block body  218  is inlet wall  206 . It is sized sufficiently large to freely pass cable  502  while small enough to prevent passage of collet  300 . The portion of inlet wall  206  adjacent rear end surface  209  may be tapered as illustrated in the embodiment of  FIG. 12  to assist loading of cable  502  therethrough. 
         [0109]    In body  218  of housing  200  is one or more control features for use by an instrument for control of body  218  during implantation. In this embodiment ( FIG. 6-7 ) a control feature is in the form of control slots  230  inscribed in opposing first and second side surfaces  208 A and  208 B. Portions of an instrument occupy these slots during insertion of the implant. In alternative embodiments, control slots  230  may be open at one end. The slot may be internally rounded to ease insertion and release of the instrument. In preferred forms the elongate side of the slot is perpendicular to the locking cap drive axis (Axis B) for improved functionality in minimally invasive procedures. In this manner, loading and unloading of housing  200  in and out of an insertion instrument is performed generally perpendicular to the surgical axis thereby providing the surgeon capability to advance or retract the insertion instrument and implant along the surgical axis with little fear of an implant unintentionally releasing from an instrument. 
         [0110]    In this embodiment, a preferred axis of implant insertion is generally coincident to axis B. In preferred forms, an insertion instrument used to insert a fixation assembly portion  102  will also have an elongate axis generally parallel if not coincident with Axis B. This arrangement between instrument and implant minimizes the necessary diametrical profile of the implant and instrument during insertion and consequently minimizes the diameter of incision required resulting in reduced surgical tissue damage. Despite these advantages, in other forms the elongate side of the slot may be positioned parallel or at a different predetermined angle to the locking cap drive axis. In other forms, a control feature may take the form of a boss or ridge. 
         [0111]    Cable collet  300  is illustrated in  FIGS. 18-19 . The collet  300  in this embodiment comprises two or more collet sections  314  as illustrated in  FIG. 19A . Each collet section  314  is preferably a duplicate of each other and when assembled substantially from a 360 degree cable collet  300 . Each collet section  314  comprises a curved body  311  with central aperture  306  extending therethrough along axis ‘C’ defining cable surface  301 . When cable collet  300  is in an uncompressed configuration (unlocked) central aperture  306  is sufficient in diameter to pass cable  502 . In a compressed configuration (locked) central aperture  306  is reduced wherein cable lock surface  301  binds against cable  502  preventing the cerclage loop from loosening. The body  311  comprises a bottom face  307 , a top face  303 , a first lock wall  305 A, a second lock wall  305 B, and a head face  302 . The body  311  may comprise other tapered surfaces such as assembly taper  304  used to prevent binding by the collet on other structures during assembly or when transitioning between compressed and uncompressed configurations. Each collet section  314  comprises one or more gap walls  310 . Gap walls of opposing collet sections are spaced by a gap that reduces in width as the collet is compressed about the cable  502  during locking. 
         [0112]    Lock cap  400  ( FIG. 14-17 ) comprises a cylindrical body  410  with axis aperture  401  extending along axis D. Extending from top surface  411  is drive pocket  408  configured to receive a driver tip from an instrument. Drive pocket  408  defines drive surfaces  407 . At the bottom of drive pocket  408  is pocket base  409 . Axis aperture  401  is sufficient in diameter to pass cable  502  through compression wall  403  and defines cable wall  402 . Compression wall  403  is configured to complement first lock wall  305 A of collet  300  to cause each collet section to move toward central axis C as lock cap  400  is advanced. For example compression wall  403  may be stepped or sloped as illustrated in  FIG. 16 . Cap fix wall  406  of lock cap  400  engages fixation wall  202  of clamp housing  200  for locking. In this embodiment, fix wall  406  and fixation wall  202  have complementing threads. Threads on fix wall  406  may include a lead-in taper  405  to ease starting of threads. Drive lead  412  comprises a plurality of sloped surfaces drafted downward from top surface  411  to a predetermined depth within drive pocket  408 . The drive lead  412  eases alignment and insertion between the head of a driver instrument as the user attempts to insert it into drive pocket  408 . Drive lead  412  is absent in alternative embodiments such as illustrated in  FIG. 15A . 
         [0113]    Cerclage cable  500  comprises a cable  502 , a cable drum  501  at cable head  504 , and a cable lead ( FIG. 1 ). The cable lead is the free end of the cable and comprises a swaged rounded tip to keep all cable strands tightly wound for eased entry into cable apertures. 
         [0114]      FIGS. 21-23  illustrate various cross-sectional views of one form of a cable fixation device illustrated in  FIG. 20 . In addition, these views illustrate preferred forms of a cable fixation device having a locking cap anti-back out feature. Surfaces formed on a friction wall  221  (previously passage wall  201 ) of housing  200  and on interference boss  413  of lock cap  400  are configured for frictional interfere with each other as lock cap  400  approaches full advancement to a locked configuration. Frictional forces created between the interference boss  413  and frictional wall  221  are sufficient to prevent unintended back out of lock cap  400  yet requires minimal additional advancement force to overcome the friction during locking and unlocking. As illustrated in the embodiment of  FIG. 20 , interference boss  413  is in the form of a protruded ring shaped ridge having a diameter slightly larger than the major diameter of fix wall  406  on locking cap  400 . Also in  FIG. 20  is friction wall  221  illustrated in the form of a flat annular surface having a diameter slightly smaller than the surface of interference boss  413 . 
         [0115]      FIG. 21  is a cross-sectional view through plane E-E illustrating a locking cap  400  as it is advanced down fixation wall  202 .  FIG. 22  is a cross-section view through plane F-F along axis B illustrating advancement of lock cap  400  prior to interference occurring between friction wall  221  and interference boss  413 .  FIG. 23  illustrates further advancement of the lock cap  400  just as interference begins to occur between interference boss  413  and friction wall  221 . Advancement of lock cap  400  will continue until fully compressed against collet  300  to fix position of cable  502  and thus preventing release of cable tension. 
         [0116]    The cable fixation device  100  is preferably pre-assembled for surgery with collet  300  loosely seated within compression walls  204  and lock cap  400  partially threaded within fixation wall  202 . The cable drum  501  is pre-seated within drum walls  205 . A cable fixation device  100  is utilized by wrapping a free end of a cable around the bone or bone segments to be stabilized. A cable passer may be utilized for this purpose. Free cable lead  506  end of cable  502  is fed through inlet wall  206  of clamp housing  200 , through the central aperture  306  of the collet, through an axis aperture  401  of cable wall  402  of lock cap  400 , through a central cable aperture of a driver tip, and finally into adjacent cable tensioner tool (not shown) abutting tensioner face of a cannulated driver. 
         [0117]    Slack in cable  502  is removed and the tensioner is clamped on the cable. The cable is tightened to a predetermined amount therein causing the cerclage loop around the bone to tighten and feet  215  to engage the bone surface. At this point the surgeon rotates handle to drive lock cap  400  into threaded housing therein compressing collet  300  against cable  502  and locking construct at specified tension. If the surgeon chooses, driver handle may be derotated to loosen and remove the cable fixation device  100  or to retension to an alternative tension level before relocking. 
         [0118]    One embodiment of a cable implant inserter construct  106  is illustrated in  FIG. 24 . The construct  106  is illustrated comprising a cerclage inserter  108  instrument portion engaged with a cable fixation device  100  implant. In this embodiment cerclage inserter  108  comprises an implant clasp portion  600 , an engagement activator  700  portion, a provisional  800 A and final  800 B locking cap driver portion, and a control portion  900 . Cerclage inserter frame  120  houses many of the inserter  108  components. 
         [0119]    Clasp portion  600  in this embodiment is in the form of a deflectable clamp operable to secure or release a clamp housing  200  therein. Clasp portion  600  is driven by a clasp activator  700  illustrated here in the form a lever  770  ( FIG. 27 ) extending from a side of inserter instrument  108 . Proximal directed forces by a user on lever  770  causes inserter  108  to operate in a release configuration whereby fixation assembly portion  102  is free to release from inserter instrument  108 . Distally directed forces by a user on lever  770  causes inserter  108  to operate in a hold configuration whereby clasp portion  600  restrains fixation assembly  102  to inserter instrument  108 . 
         [0120]    Cerclage inserter frame  120  is illustrated in  FIGS. 31 and 32 . Frame  120  comprises a frame body  122 . Extending from a distal end of body  122  are a pair of opposed elongate clasp arms  124  (also referred to as a clamp base) defining a pair of opposed arm faces  128  which in turn define a clamp window  126 . Clasp window  126  has size and profile to fit clamp housing  200  therein. Extending from arm faces  128  are one or more opposed restraint ribs  130  (also known as control arms) also with size and profile for fit within control slot  230 . In this embodiment, arm faces  128  comprise a plurality of restraint ribs  130  that are generally rectangular in shape and orientated perpendicular to elongate axis-F that extends through inserter frame  120 . Restraint ribs  130  may comprise a lead-in taper at one or more ends of the rib  130  to ease loading or removing a fixation assembly portion  102  from clamp window. In some embodiments, two or more restraint ribs  130  are aligned and extend from an arm face  128 . Clasp arm  124  may also be distally tapered, rounded, or both to ease movement of inserter instrument  108  through soft tissue during surgery. 
         [0121]    Extending from opposed frame legs  132  is pod  148  just proximal clamp window  126 . Relief channel  134  divides pod  148  serving to facilitate opposed frame legs  132  to deflect inward or away from Axis-F. Extending through pod  148  along Axis-F is pod passage face  152  which defines a pod aperture  154  therein. 
         [0122]    Proximal to pod  148  are opposed long faces  156  defining long aperture  146 . Long face  156  continues proximal and merges with slide face  158  to define slide aperture  144 . Adjacent slide aperture  144  within one of frame legs  132  is pivot recess  142  configured for receiving a threaded or pressed pin. Disposed on a lateral surface of an opposed frame leg  132  is a distal lever notch  140  and spaced proximal a proximal lever notch  138 . Intermediate face  160  defines intermediate aperture  164  and proximal face  162  defines proximal aperture  166 . Extending through frame body  122  between intermediate face  160  and proximal face  162  is provisional face  170  defining provisional aperture  172 . 
         [0123]    Disposed on the proximal end of frame body  122  are features to secure and orientate a control portion  900  to frame body  122 . Control positioner  174  is raised into control  900  and orientates the rotational and center position of control portion  900  along Axis F. Control face  176  abuts control portion  900 . Pin pocket  178  houses a race pin  911 extending proximally for alignment of a control race  908 . Bearing face  180  situated normal to Axis F provides a flat surface for rolling of bearings.  FIG. 32A  also illustrates a variety of apertures as defined earlier extending along Axis-F through frame body  122 . 
         [0124]    A clasp activator  700  of cerclage inserter  108  comprises a series of components that work together to engage and disengage a lock driver  702  with a lock or locking cap of a cable fixation device  100 . One embodiment of a lock driver  702  is illustrated in  FIG. 28 . Driver  702  comprises a cannulated rod  704  with central axis-G and with a driver head  706  at a distal end. Driver head  706  comprises drive faces  708  configured to engage complementing drive surfaces  407  in drive pocket  408  of lock cap  400 . In a preferred embodiment, drive faces  708  form a multi-lobe profile. Cannulated rod  704  is perforated along its length with cleaning apertures  710  extending from an outer surface to an inner cannula  712  which extends end to end. A finger wheel  714  portion is provided for a user to adjust the axial position or radially adjust driver  702  to ease insertion into a lock cap. First crank faces  724  are configured for sliding engagement with a bevel gear that is part of a final locking cap driver portion  800 B. In this embodiment, first crank faces  724  are in the form of a hex profile as are second crank faces  718  which are spaced distally from first crank faces  724  by mid groove  720 . First crank faces  724  and second crank faces  718  are aligned. Proximal to first crank faces  724  is proximal axial surface  722 . Mid axial surface  728  is positioned between finger wheel  714  and second crank faces  718 . Butt face  726  resides on the proximal end of driver  702 . 
         [0125]    A ram  740  is housed within a long aperture  146  and slide aperture  144  of frame body  122 . One embodiment of a ram  740  is illustrated in  FIG. 29-30 . Ram  740  comprises a ram body  742 . A bore  744  of various diameters extends down the length of ram  740  along axis-H forming a first aperture  746  at a distal end, a second aperture  748  offset from a proximal end, and a third aperture  750  at a proximal end. Pod channel  752  extends into a distal end of ram body  742  and is defined by opposing channel faces  754 . Pod channel  752  is sized and shaped for fit over pod  148  of inserter frame  120  in a hold configuration therein causing channel faces  754  to bind against opposing outer sides of pod  148  thereby limiting outward deflection of frame legs  132  such that clamp housing  200  may be held firmly within clamp window  126 . Entry taper  760  is used along with tapers on pod  148  to ease movement of ram  740  as it is forced distally against pod  148 . 
         [0126]    First aperture  746  is sufficient in diameter to slidingly house main rod  730  portion of cannulated rod  704 . Second aperture  748  and third aperture  750  are sufficient in diameter to slidingly house mid axial surface portion  728 . A view aperture  756  extends through ram body  742  and is defined by opposing view faces  762 . Pivot face  764  defines pivot bore  766  which extends through ram body  742  at a proximal end. 
         [0127]    A clasp activator  700  of cerclage inserter  108  comprises a series of members cooperating to control ram  740  causing clasp  600  to transition between hold and release configurations. Clasp activator  700  comprises in one embodiment a lever  770  extending from a cerclage inserter  108 . In preferred forms the lever is saddle shaped as illustrated in  FIGS. 27 and 27A . Lever  770  comprises a lever handle  772  portion extending from a pair of opposed pivot rings  774 . Lever handle  772  may be covered by lever cap  776 . Each pivot ring  774  comprises a pivot bore  778  of a diameter sufficient to house lever pin  780 . Extending generally perpendicular through lever pin  780  is drive bore  784  defined by drive bore walls  786  having diameter sufficient to pass mid axial surface  728  of lock driver  702 . Lever spring  782  cooperates with spring pin  790  and spring clip  792  to form a functional spring pin. Spring pin head  794  engages proximal and distal lever notch  138  and  140  to releasably hold in one position or other as lever  770  is moved therebetween to activate a release or hold configuration. Fixed pivot channel  788  extends across both pivot rings  774  and is sized to pivot about fixed pivot pin  761  extending from pivot recess  142  in frame body  122 . 
         [0128]      FIG. 26A  illustrates the distal end of cerclage inserter  108  when in a hold configuration. Ram horns  758  enclose pod  148  therein preventing separation of frame legs  132  and consequently firmly holding clamp housing  200  (not shown) within clamp window  126 . Deflection cams  136  are resting within the respective cam pockets  759 . Activation of lever handle  772  to release configuration will cause ram  740  to move proximally and away from pod  148 . Deflection cams  136  are forced out of cam pockets  759  causing a consequent outward deflection of frame legs  132  therein widening clamp window  126  for removal of cable fixation device  100 . In this release configuration, clamp housing  200  and remaining members of cable fixation device  100  may also be loaded into clamp window  126  ( FIG. 25A ) by aligning restraint ribs  130  with control slots  230  and moving housing  200  to a position of alignment between axis-F and axis-B as illustrated in  FIG. 25 . Housing  200  is then firmly held in this position by activation of lever  770  to a hold configuration. 
         [0129]    A provisional locking cap driver portion  800 A may be utilized to provide provisional locking of a lock cap  400 . One embodiment of this assembly is illustrated in  FIGS. 26, 27, 27B, and 27C . Provisional lock driver portion  800 A comprises a thumb cup  802  having an engagement bore  808  extending through the middle of cup  802  along a central axis-J with distal engagement face  817  configured to engage second crank face  718  and proximal crank face  818  configured to engage first crank face  724  on lock driver  702 . Disassembly button  806  and springs  807  reside in button receiver  813 . Restraint pin  814  disposed in restraint pin aperture  816  holds button  806  within button receiver  813 . Springs  807  bias button  806  away from receiver wall  815  which defines the three enclosed radial sides of button receiver  813 . As a consequence, button wall  809  is forced against mid groove  720  of lock driver  702  keeping driver head  706  of lock driver  702  extended in drive pocket  408  of lock cap  400 .  FIG. 38  illustrates button  806  operation with benefit of several components removed. 
         [0130]    When assembled and in an operational mode, imparting a rotary force by the user on thumb face  810  will result consequential rotation of lock driver  702  and advancement of lock cap  400 . Distal bearing  803  is sandwiched between inner floor  811  of thumb cup  802  and distal bearing race  804 . Thumb restraint  805  snapped into cup rim  812  holds this assembly together. (Distal bearing  803  is erroneously shown below thumb cup instead of inside adjacent inner floor—see  FIG. 27B ). 
         [0131]    Depressing button  806  against the biasing spring force moves button wall  809  out of mid groove  720  thus permitting lock driver  702  to be retracted out of drive pocket  408  of lock cap  400  typically by manual distraction on finger wheel  714 . Similarly, bias button  806  may be used to disassemble cerclage inserter  108  such that individual components can be cleaned. For example, control portion  900  may be removed, then bias button  806  depressed for removal of lock driver  702  as illustrated in  FIG. 37 . Upon removal of lock driver  702 , other components such as provisional lock cap driver portion  800 A may also be removed for cleaning. 
         [0132]      FIG. 27  illustrates an exploded view of a preferred embodiment of cerclage inserter  108  including a control portion  900  and internal components. Control portion  900  comprises control handle  902  formed from control body  901  and is further illustrated in  FIGS. 33-36 . Grip surface  903  is available to the user to grip and control cerclage inserter instrument  108 . One or more grip apertures  914  extend through grip surface  903  to provide additional user grip friction when handling instrument, reduce weight, to access components located inside control handle  902 , and for cleaning access. One or more grip grooves  920  may also extend in control body for gripping purposes and weight reduction. End pocket walls  933  radially define an open end pocket  917  at proximal end of control handle  902 . Floor  934  is generally perpendicular to axis-M and divides end pocket  917  from distal pockets  928  and  922 . Extending proximally along axis-M from floor  934  is drive shaft  918  terminating with tensioner platform  915  for abutting a tensioner device and wherein drive shaft  918  is further defined by radially placed drive faces  919  here in the form of a hex which may be used to impart rotation during assembly of components. Inside control body  901  and extending generally parallel to axis M is inter-pocket wall  927  defining boundary of control pocket  928  and secondary bevel gear pocket  922 . Gear pocket wall  929  also defines pocket  922 . Inner gear shaft face  924  formed in inner-pocket wall  927  and outer gearshaft face  925  formed in gear pocket wall  929  define gearshaft aperture  923 . Control aperture  916  is sized to pass a surgical cable  502  as are other central axis apertures defined earlier such that cable may be extended through instrument  108  to cable fixation device  100 . 
         [0133]    Primary bevel gear  909  and secondary bevel gear  910  cooperate to transit forces applied by a user through a torsion wrench  935  to rotate lock driver  702  and advance lock cap  400 . Torsion wrench  935  comprises a wrench handle  936  for grasping by a user and a wrench drive  937 , such as a hex for example, configured to transmit forces through complementing inner coupler drive faces  938  to outer coupler drive faces  943  of drive coupler  912  to secondary drive face  945  on secondary bevel gear  910 . As illustrated in the section view of  FIG. 27D , drive coupler  912  comprises an extended coupler boss  939  with coupler groove  940  configured to seat secondary bevel clip  913  therein. Coupler taper  942  may be used to assist entry of wrench drive  937  and snap groove  941  may be used to prevent unintended release of torsion wrench  935 . Coupler  912  resides in gearshaft aperture  923  and extends through secondary bevel gear  910  which is housed within secondary bevel gear pocket  922  and held in position by coupler rim  944  and secondary bevel clip  913  of drive coupler  912 . 
         [0134]    Primary bevel gear  909  comprises primary drive faces  946  configured to complement and rotably engage first crank faces  724  of lock driver  702  and wherein lock driver  702  is free to slide against drive faces  946  relative to axis G.  FIG. 27B  illustrates internal components of cerclage inserter  108  with components  902 ,  802 , and  122  displaced to the side. Primary bevel gear  909  is housed distally within control pocket  928  rotating above proximal bearing  906  and proximal race  908 . 
         [0135]    Control restraint clip  904  spans spring groove  182  on frame body  122  and control groove  926  to releasably secure control portion  900  to frame body  122 . Wave spring  905  tightens gaps between interfacing components. Proximal bearings  906  are partially disposed in proximal race  908 . The outer perimeter of proximal race  908  comprises race threads  931  to complement handle threads  921  of control handle  902  for threaded engagement therebetween. Proximal race  908  comprises a plurality of race holes  932  in which proximal bearing  906  is housed. Race pin  911  extends from race pin hole  184  through one of race holes  932  to maintain threaded position of proximal race  908  after fully threaded into control handle  902 . Control restraint ring  907  maintains position of components. 
         [0136]    A 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 . A cable drum  501  is pre-seated within head walls  205 . A surgical kit may be provided for use in the surgical suite comprising the cable fixation device, a cerclage inserter, a cable passer, and a cable tensioner. 
         [0137]    In one embodiment, a surgical method for utilizing a cable fixation device  100  begins with the step of passing a free end of a surgical cable though an incision and around a bone or bone segments to be stabilized ( FIG. 39 ). A surgical cable passer known in the art (not shown) may be utilized for this purpose. The passer typically comprises a passer handle connected to a passer shaft for guiding a semi-circular passer tube around the outer surface of the bone. A surgical cable is fed into the passer tube until exposed out the other side. The passer may then be removed leaving surgical cable encircled around the bone. 
         [0138]    The user activates clasp activator  700  assuring ram is distracted proximally causing ram  740  to deflect frame legs  132  outward causing a consequent widening of clamp window  126 . Control slots  230  on cable fixation device  100  are then aligned with restraint ribs  130  within clamp window  126  of cerclage inserter  108 . Clamp housing  200  is moved generally perpendicular within clamp window  126  until restraint ribs  130  seat in control slots  230  wherein driver head  706  is aligned with drive pocket  408 . The user activates clasp activator  700  by moving lever handle  772  distally causing ram  740  to also move distally. Ram horns  758  pinch sides of pod  148  together resulting in a consequent narrowing of clamp window  126  therein firmly holding clamp housing  200  therebetween opposing arm faces  128 . 
         [0139]    The user then advances distally by hand lock driver  702  wherein driver head  706  occupies drive pocket  408  of lock cap  400 . Button  806  may move against lock driver rod  702  causing it to be restrained from axial movement. 
         [0140]    A lead  506  of cable  500  is then fed through inlet wall  206  of clamp housing  200 , through a central aperture  306  of collet  300 , through a cable wall  402  of lock cap  400  and through inner cannula  712  of lock driver  702 . The surgeon may continue to thread cable lead  506  into a surgical cable tensioning device. Alternatively, the surgeon may immediately apply a provisional tension on cable  500  by hand and provisionally fix cable  500  within fixation assembly  102  by finger advancing thumb cup  802  by hand until lock cap  400  is sufficiently snug thereby retaining cable tension in cerclage  500 . 
         [0141]    For final tensioning and locking, a surgical cable tensioner (common in the prior art) may be used. Cable lead  506  is threaded into the cable tensioner until all cable slack is removed and cable tensioner abuts tensioner platform  915  on control handle  902 . The cable is restrained in the cable tensioner and thumb cup or wheel  802  is advanced in an opposite direction by hand until lock cap  400  is loosened thereby freeing cable  500  in cerclage to be retensioned. The surgeon then tensions the cable to a predetermined level using the tensioner. 
         [0142]    The surgeon then uses a torsion wrench  935  to advance drive coupler  912  causing consequent rotation of secondary bevel gear  910  and primary bevel gear  909  which causes consequent rotational advancement of lock driver  702 . This causes lock cap  400  to advance and restrain cable  500  at desired tension within tightened collet  300 . This process of loosening lock cap, retensioning, then retightening lock cap may be repeated without damage to the surgical cable. 
         [0143]    The user then retracts lock driver  702  proximally to remove driver head  706  from drive pocket  408  which may require simultaneous depression of button  806 . The user again activates clasp activator  700  assuring ram  740  is distracted proximally causing ram  740  to deflect frame legs  132  outward causing a consequent widening of clamp window  126 . Cerclage inserter instrument  108  is moved in a direction generally parallel to control slots  230  thereby causing release of clamp housing  200  from instrument  108 . The cerclage inserter instrument  108  is then retracted proximally and removed from the surgical site. Wound closure may ensue. 
         [0144]    In an alternative method, portions of the cable fixation device  100  may be assembled during surgery. In preferred embodiments head of cable  502  is configured in size to be passable through the cable passer then assembled with clamp housing  200  after the passer instrument is removed. This feature provides for the cable  502  to be passed in either direction through the passer tube. 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 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  502  through cable slot  213 . Cable  502  is pulled until cable drum  501  is seated in head aperture  212  and against head stop surface  1220 . This assembly during surgery feature is made possible by cable slot  213  as it provides a path for cable drum  501  to be seated in head aperture  212  without requiring cable lead  506  to pass through head aperture  212  first. 
         [0145]    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.