Abstract:
A device for treating bone fractures, comprises an actuating mechanism removably coupleable to a clamping mechanism including a clamp defining a cable receiving channel extending therethrough and a compression member coupled to the clamp for movement relative thereto, movement of the compression member relative to the clamp in a first direction moving the clamping mechanism into a clamping configuration in which at least a portion of the clamp is compressed into the channel to fix a cable received therein relative to the clamping mechanism. The actuating mechanism includes a first member and a second member removably engagable with a clamping mechanism so that, when engaged, relative movement between the first and second members causes relative movement between the clamp and the compression member to move the clamping member between the clamping configuration and a release configuration, the actuating mechanism further including a tensioning mechanism.

Description:
PRIORITY CLAIM 
     This application is a National Phase application of PCT Patent Application Serial No. PCT/US2009/033404 filed on Feb. 6, 2009 which claims priority to the U.S. Provisional Application Ser. No. 61/026,807, entitled, “PELVIC CABLE SOLUTION” filed on Feb. 7, 2008. The specifications of the above-identified applications are incorporated herewith by reference. 
    
    
     BACKGROUND 
     Acetabular (hip socket) fractures are serious orthopedic injuries usually resulting from significant trauma. Surgery to realign and stabilize the displaced joint surfaces (e.g., using plates and screws), allows the patient to avoid traction and prolonged bedrest and accurate fracture realignment promotes improved bone and cartilage healing, which in turn improves long-term results. Early fracture stability allows comfortable hip movement which improves joint cartilage healing. Additionally, this allows patients to be out of bed and ambulatory. 
     However, acetabular fractures with medial displacement patterns, particularly those with medial displacement of the quadrilateral surface, may be technically challenging to treat. The location of the affected area deep in the pelvic part of the abdominal cavity, minimal bone stock and difficulty obtaining stable internal fixation in the true pelvis contribute to the surgical challenge of open reduction and internal fixation of such fractures. Applying a medial buttress plate across the quadrilateral surface may assist in preventing the femur head from penetrating into the pelvic cavity. However, because of the limited access to the quadrilateral surface and the thin bone structures around the acetabulum, it is often difficult to treat such fractures with standard plates and screws. Although procedures have previously been described for treating quadrilateral surface fractures, there is still no optimal mechanical solution. Most of the techniques involve fixations with forces acting at 90° to a screw axis, which may, when bone thickness is limited, result in a cut out of the screws. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a device for treating bone fractures, comprising an actuating mechanism removably coupleable to a clamping mechanism including a clamp defining a cable receiving channel extending therethrough and a compression member coupled to the clamp for movement relative thereto, movement of the compression member relative to the clamp in a first direction moving the clamping mechanism into a clamping configuration in which at least a portion of the clamp is compressed into the channel to fix a cable received therein relative to the clamping mechanism. The actuating mechanism includes a first member removably engagable with a clamping mechanism so that, when engaged, the first member prevents relative movement between the clamp and the first member, a second member removably engagable with a clamping mechanism and movably coupled to the first member so that, when engaged, the second member prevents relative movement between the compression member and the second member, relative movement between the first and second members causing relative movement between the clamp and the compression member to move the clamping member between the clamping configuration and a release configuration in which the cable is permitted to move through the clamping mechanism and a tensioning mechanism for drawing the cable through the clamping mechanism and applying a desired degree of tension thereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a system of an exemplary embodiment of the present invention, with all its components fully assembled; 
         FIG. 2  shows a perspective view of a handle of an exemplary system of the present invention; 
         FIG. 3  shows a perspective view of longitudinal member of an exemplary system of the present invention; 
         FIG. 4   a  shows a perspective view of a clamping mechanism according to an exemplary system of the present invention; 
         FIG. 4   b  shows a first perspective view of a clamping mechanism according to an exemplary system of the present invention; 
         FIG. 5   a  shows a second perspective view of a clamp according to an exemplary embodiment of a system according to the present invention; 
         FIG. 5   b  shows a front plan view of the clamp of  FIG. 5   a;    
         FIG. 6   a  shows a perspective view of a clamping ring according to an exemplary embodiment of a system of the present invention; 
         FIG. 6   b  shows a front plan view of the clamping ring of  FIG. 6   a;    
         FIG. 7   a  shows a first perspective view of a longitudinal member assembled with a clamping mechanism according to an exemplary embodiment of a system of the present invention; 
         FIG. 7   b  shows a second perspective view of a longitudinal member engaging a clamping mechanism according to an exemplary embodiment of a system of the present invention; 
         FIG. 7   c  shows a third perspective view of a longitudinal member engaging a clamping mechanism according to an exemplary embodiment of a system of the present invention; 
         FIG. 8  shows an anatomically repositioning a fractured bone, according to an exemplary embodiment of a method of the present invention; 
         FIG. 9  shows the insertion of a cable (e.g., a Kirschner wire) from a dorso-lateral side of a pelvic bone through the repositioned quadrilateral surface of a bone fragment, according to an exemplary embodiment of the present invention; 
         FIG. 10  shows holding a repositioned bone fragment, according to an exemplary embodiment of the present invention; 
         FIG. 11  shows drilling a hole through the fractured bone, according to an exemplary embodiment of the present invention; 
         FIG. 12  shows assembling a component of an exemplary system, according to an exemplary embodiment of the present invention; 
         FIG. 13  shows inserting a cable into the drilled hole in the fractured bone, according to an exemplary embodiment of the present invention; 
         FIG. 14  shows the buttress plate abutting the surface of the bone, according to an exemplary embodiment of the present invention; 
         FIG. 15  shows inserting a cable into the drilled hole in the fractured bone, according to an alternate exemplary method of the present invention; 
         FIG. 16  shows positioning a buttress plate, according to the alternate exemplary method of  FIG. 15 ; 
         FIG. 17  shows assembling components of an exemplary system, according to an exemplary method of the present invention; 
         FIG. 18  shows other components of an exemplary system, according to an exemplary method of the present invention; 
         FIG. 19  shows assembled components of an exemplary system, according to an exemplary embodiment of the present invention; 
         FIG. 20  shows the components of the present invention, fully assembled, according to an exemplary embodiment of the present invention; 
         FIG. 21  shows tensioning and crimping a cable, according to an exemplary embodiment of the present invention; 
         FIG. 22  shows implanted components of an exemplary system, according to an exemplary embodiment of the present invention; 
         FIG. 23  shows inserting additional screws through a plate, according to an exemplary embodiment of the present invention; and 
         FIG. 24  shows a perspective view of a clamping mechanism according to an alternate embodiment of the present invention, in a first configuration; 
         FIG. 25  shows a perspective view of the clamping mechanism of  FIG. 24 , in a second configuration; 
         FIG. 26  shows a side view of the clamping mechanism of  FIG. 24 , in the first configuration; 
         FIG. 27  shows a side view of the clamping mechanism of  FIG. 24 , in the second configuration; 
         FIG. 28  shows a bottom view of the clamping mechanism of  FIG. 24 , in the first configuration; and 
         FIG. 29  shows a bottom view of the clamping mechanism of  FIG. 24 , in the second configuration. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention, which may be further understood with reference to the following description and the appended drawings, relates to a system and method for treating fractures, and in particular relates to internal fixation devices for treating fractures. Specifically, exemplary embodiments of the present invention describe a system and method for securing a cable or wire through the fractured quadrilateral surface of the acetabulum. It should be noted however, that although the embodiments of the present invention are described in regard to the application of a buttress plate to the quadrilateral surface of the acetabulum using surgical cable or wire, the present invention is relevant to the use of cable or wire to secure any bone fixation device to any bone. 
     As shown in  FIGS. 1-6 , a system according to an exemplary embodiment of the present invention includes a handle  6  for tensioning a cable  56  and a longitudinal member  4  for operating a clamping mechanism  2  to secure a clamp  8  about the cable  56  fixing the cable  56  at a desired location and tension as will be described in more detail below. The longitudinal member  4  is coupled to the handle  6  so that the cable  56  may be passed into the longitudinal member  4  and therethrough into the handle  6 . As will be described in more detail below, the cable  56  is first inserted through and coupled to a bone plate  50  passed through a fractured bone and then fed through a clamping mechanism  2  into the longitudinal member  4  and from there into the handle  6 . The longitudinal member  4  engages the clamping mechanism  2  which includes a clamping ring  10  screwed over a threaded, proximal end of a clamp  8  such that rotation of the longitudinal member  4  rotates the clamping ring  10  over the clamp  8 , crushing the clamp  8  and securing it over the cable  56  maintaining a position of the clamp  8  on the cable  56 . Thus, any tension on the cable  56  at this point is maintained by the clamp  8  securing the bone plate  50  against the fractured bone. 
     As shown in  FIG. 2 , the handle  6  is preferably longitudinally shaped to facilitate handling by a user with a channel  76  extending therethrough for slidably receiving the cable  56 . However, those skilled in the art will understand that the shape of the handle is not critical to the invention and may be any selected shape. The channel  76  extends to a tensioning mechanism operated by a knob  72  formed, for example, at a proximal end of the handle  6 . As would be understood by those skilled in the art, the tensioning mechanism may, for example, include a spool coupled to the knob  72 . The cable  56  is coupled to the spool and a ratchet mechanism (or other suitable device) maintains tension on the cable  56  as the cable  56  is wound up on the spool by rotation of the knob  72 . As would be understood by those skilled in the art, the tensioning mechanism may further include a manual release disengaging the ratchet mechanism to release tension from the cable  56  as desired. The handle  6  may further include an indicator or scale allowing a user to determine a current level of tension on the cable  56 . A distal end  66  of the handle  6  is adapted to be coupled to the longitudinal member  4  as will be described in more detail below. In an exemplary embodiment, the distal end  66  may includes a recess adapted to receive a complimentarily shaped proximal end of an inner sleeve  32  of the longitudinal member  4  to prevent rotation of the end of internal sleeve  32  relative to the handle  6 . 
     As shown in  FIG. 3  and mentioned above, the longitudinal member  4  comprises an outer sleeve  30  and an inner sleeve  32  rotatably housed therewithin. A distal end of the outer sleeve  30  includes a recess  34  shaped to engage a proximal end of the clamping ring  10  preventing the clamping ring  10  from rotating relative thereto. In a preferred embodiment, for example, the recess  34  and the proximal end of the clamping ring  10  are hexagonally shaped. However, those skilled in the art will understand that any of a variety of shapes may be selected for the clamping ring  10  and the recess  34  so long as the two elements are non-rotatable relative to one another when coupled together. A proximal end  36  of the outer sleeve  30  may be shaped to facilitate engagement with a wrench, or other tool for applying torque thereto to rotate the outer sleeve  30  about a longitudinal axis thereof while the handle  6  is held stationary. A distal end  38  of the inner sleeve  32  includes a mating feature sized and shaped to non-rotatably engage a proximal end of the clamp  8  (e.g., via a hole in the proximal end of the clamping ring  10 ). Thus, the rotation of the outer sleeve  30  relative to the handle  6  and, consequently, the inner sleeve  32 , causes the clamping ring  10  to rotate relative to the clamp  8 , screwing the clamping ring  10  over the clamp  8 . In a preferred embodiment the distal end  38  may be crown-shaped. As indicated above, a proximal end  40  of the inner sleeve  32  extends through the outer sleeve  30  to non-rotatably engage a distal end  66  of the handle  6  with a channel  74  extending through the inner sleeve  32  being in communication with the channel  76  of the handle  6 . Thus, as shown in  FIGS. 4   a  and  4   b , the cable  56  may pass through the longitudinal member  4  via channel  74  into the handle  6  and pass therethrough to the tensioning mechanism via the cannel  76 . In an exemplary embodiment, the proximal end  40  may be hexagonally shaped to be received within a hexagonal recess of the distal end  66  of the handle  6 . 
     As shown in  FIGS. 5   a  and  5   b , the clamp  8  includes a head  12  and a body  14  extending proximally from the head  12  to a proximal end  18 . The head  12  of the clamp  8  may be spherically shaped to adapt to the bone surface. However, it will be understood by those of skill in the art that the head  12  may be of a variety of shapes. The body  14  may be tapered with a diameter of a distal end  16  thereof slightly greater than that of the proximal end  18 . The clamp  8  may further include a channel  20  extending therethrough so that the cable  56  may pass through the entire length of the clamp  8 . The channel  20  may be substantially cylindrical and extend along a longitudinal axis of the clamp  8 . Alternatively, the channel  20  may taper with the shape of the body  14 . The body  14  may include threading  24  along all or a portion of its length and includes at least one slot  22  extending substantially longitudinally therethrough from the proximal end  18  toward the distal end  16 . The longitudinal slots  22  may be parallel to the longitudinal axis of the clamp  8  along at least a portion of a length of the body  14  at its proximal end  18 . The longitudinal slots  22  may, for example, be positioned substantially symmetrically about the longitudinal axis such that separated portions  62  of the proximal end  18  created by the longitudinal slots  22  are free to flex radially into the channel  20  against the cable  56 . For example, in an exemplary embodiment, two longitudinal slots  22  substantially orthogonal to one another divide the proximal end  18  of the body  14  into four substantially equally sized and spaced portions  62 . 
     As indicated above, the body  14  is threaded to engage a threading of a channel  26  of extending through a clamping ring  10  formed, for example, as a nut. A distal end of the channel  26  is sized and shaped to receive larger distal end  16  of the body  14  while a chamfer  29  necks down a proximal portion of the channel  26  so that, as the clamping ring  10  is threaded further distally over the body  14 , the reduced diameter proximal portion of the channel  26  engages the portions  62  of the clamp  8  and forces them radially into the channel  20  against the cable  56 . In a preferred embodiment, an outer surface  64  of the clamping ring  10  is hexagonally shaped to engage a corresponding recess  34  in the outer sleeve  30  as shown in  FIGS. 7   a - 7   c . It will be understood by those in the art however, that the outer surface  64  of the clamping ring  10  may take any shape so long as the outer surface  64  of the clamping ring  10  is non-rotatably engaged by the outer sleeve  30 . As the clamping ring  10  is rotated relative to the clamp  8 , the threads  28  engage the threads  24  of the clamp  8  to draw the clamping ring  10  distally relative to the body  14  compressing the portions  62  against the cable  56 . Furthermore, as indicated above, the distal end  38  of the inner sleeve  32  engages the longitudinal slots  22  or any other feature of the clamp  8  to non-rotatably couple thereto. For example, in a preferred embodiment, the distal end  38  include projections (e.g., in the shape of an X or a cross) to extend into the longitudinal slots  22  to prevent relative rotation between the inner sleeve  32  and the clamp  8 . 
     As shown in  FIGS. 8-21 , a method according to an exemplary embodiment of the present invention provides improved mechanical buttressing of a fractured pelvis by fixing a plate over the quadrilateral surface of the acetabulum via a cable  56  and clamp  8  as described above. As shown in  FIG. 8 , to prepare for the surgical reduction of the fracture, the fractured bone  42  is anatomically repositioned (e.g., using clamps, forceps or any other surgical tool for holding the fractured bone  42  in place) and held in place as a wire is fixed to a target location on a dorso-lateral side  46  of the bone  42 , as shown in  FIG. 9 . Those skilled in the art will understand that the wire may be any thin wire that can act as a guidewire for surgical tools such as, a K-wire, which is a sterilized, sharpened, smooth stainless steel pin that may be driven into the bone using a power or hand drill. The wire may be inserted into the bone  42  until an end is within the center of a target area of the quadrilateral surface of the bone  42 , as shown in  FIG. 10 . A cannulated drill bit may then be mounted over the wire so that the wire functions as a guidewire aiming the drill to create a channel  48  through the quadrilateral surface, as shown in  FIG. 11 . Once the channel  48  has been drilled through the bone, the wire is removed from the body, while a physician continues to hold the fractured bone  42  in place. 
     As shown in  FIG. 12 , a plate  50  may be pre-assembled for implantation into the body. The plate  50  may be selected according to the type of fracture of the bone and the support required to reduce the fracture. For example, the plate  50  may include one or more buttressing wings  52  and a brim fixation wing  54 . The buttressing wings  52  may be pre-bent to adapt to the curve and shape of the quadrilateral surface. Additionally, the brim fixation wing  54  may be pre-bent to fit the curve if the pelvic brim. Alternatively, a user of the plate  50  may shape the plate  50  as desired to accommodate the anatomy of the target area as would be understood by those skilled in the art. Thus, the plate  50  is preferably formed of a material sufficiently strong to withstand the forces to which it will be exposed when implanted but which is sufficiently flexible to adapt to the shape of the bone  42  and to receive any bending required by a user. The plate  50  may be assembled with a cable  56  inserted through a hole  58  formed, for example, at or near a center thereof so that tension applied to the cable  56  draws the entire plate  50  snugly against the bone  42 . The cable  56  may be fixed to the plate  50  by any known mechanism (e.g., by an enlarged distal end  68  sized to prevent the cable  56  from slipping through the plate  50 ). Thus, if the end  68  is rounded, a diameter of the rounded end  68  is selected to be greater than the diameter of the hole  58 . The plate  50  may further include an indentation  70 , or cavity, to accommodate the end  68  of the cable  56 . It will be understood by those of skill in the art that the plate  50  need not be pre-assembled prior to implantation and that the cable  56  may be inserted through the hole  58  after the plate  50  has been positioned on the quadrilateral surface. 
     As shown in  FIGS. 13-14 , the proximal end of the cable  56  is passed through the channel  48  to the dorso-lateral side  46  of the bone  42  and pulled proximally until the plate  50  is held against the quadrilateral surface supporting the fractured bone  42 , as shown in  FIG. 14 . Once the cable  56  is pulled taught, the cable  56  will extend at an angle that is approximately 45° relative to a plane in which the plate  50  rests, minimizing the likelihood of cut-out of the bone while continuing to sufficient support to stabilize the fragments of the bone  42  in the desired position. The plate  50  is preferably positioned such the buttressing wings  52  optimally buttress the quadrilateral surface and so that the fixation wing  54  fits over the pelvic brim. 
     Alternatively, as shown in  FIGS. 15 and 16 , the cable  56  may be passed through the channel  48  from the dorso-lateral side  46  of the bone  42  such that the distal portion of the cable  56  may extend past the quadrilateral surface. The distal end  68  of the cable  56  may be enlarged, but small enough to pass through the hole  58  of the plate  50  and the channel  48  of the bone  42 . Thus, the distal end  68  is passed through the hole  58  and the plate  50  positioned against the quadrilateral surface. It will be understood by those of skill in the art that the plate  50  may have more than one hole  58  such that the distal end  68  of the cable  56  may be inserted through the hole  58  that best positions the plate  50  against the quadrilateral surface. The distal end  68  of the cable  56  may be fixed to the plate  50  via a slotted spherical washer  78 , which is affixed to the distal end  68  of the cable  56 . The cable  56  is passed through a slot of the slotted spherical washer  78 . It will be understood by those of skill in the art that an opening  80  of the spherical washer may be smaller than the distal end  68  such that the distal end  68  may not pass through the opening  80 . It will also be understood by those of skill in the art that the spherical washer  78  may be deformed such that a width of the slot is decreased, preventing the cable  56  from coming loose. Thus, when the cable  56  is pulled taught, the plate  50  is held in position against the quadrilateral surface. 
     As shown in  FIGS. 17-20 , while continuing to hold tension on the cable  56 , the proximal end thereof is threaded through a clamping mechanism  2 , into the inner sleeve  32  and from there into the handle  6  wherein it is engaged with the tensioning mechanism. The proximal end of the clamp  8  is then engaged with the distal end  38  of the inner sleeve  32  while the outer surface  64  of the clamping ring  10  is engaged with the recess  34  at the distal end of the outer sleeve  30  and the entire assembly is slid along the cable  56  until the head  12  of the clamp  8  abuts the dorso-lateral side  46  of the bone  42 . The tension through the cable  56  is then increased by actuating the knob  72  of the handle  6  in the direction of arrow A, as shown in  FIG. 21 . Those skilled in the art will understand that, during this phase, the clamping ring  10  is only screwed over the tapered proximal end of the body  14  so that the portions  62  do not engage the cable  56  and the cable  56  remains slidable through the clamp  8 . 
     It will be understood by those of skill in the art that the clamping mechanism  2  may be clamped over and released from the cable  56  as desired as the clamp  8  may be moveable between a clamping configuration in which the cable  56  is compressed by the radially inward flexing of the portions  62  and a released configuration in which the portions  62  do not compress the cable  56  by biasing the portions  62  toward the released configuration and designing the taper of the portions  62  and the chamfer  30  so that the portions  62  are not plastically deformed when moved to the clamping configuration. 
     Once the desired tension has been placed on the cable  56 , the outer sleeve  30  of the longitudinal member  4  may be rotated in direction B, about the inner sleeve  30 , such that the clamping ring  10 , to which the outer sleeve  30  is engaged, is screwed over the clamp  8  compressing the portions  62  against the cable  56  and fixing the clamping mechanism  2  on the cable  56  as described above. It will be understood by those in the art that rotating the outer sleeve  30  in one direction relative to the inner sleeve  32  (e.g., direction B) tightens the clamping ring  10  about the body  14  of the clamp  8  while rotating the outer sleeve in the opposite direction loosens the clamping ring  10  from the clamp  8  disengaging the portions  62  from the cable  56 . 
     The clamping mechanism  2 , when in the clamped configuration, maintains a desired tension on the cable  56  securing the plate  50  firmly over the quadrilateral surface of the bone  42  while the clamping mechanism  2  is secured firmly against the dorso-lateral side  46  of the bone  42 . The head  12  of the clamp  8  abuts and orients to the surface of the bone  42 , providing optimal mechanical buttressing. Once the clamping mechanism  2  has been fixed in the clamped configuration, the longitudinal member  4  and the handle  6  may be disassembled, as shown in  FIG. 20  by releasing the cable  56  from the tensioning mechanism of the handle  6  and disengaging the distal end  66  of the handle  6  from the proximal end  40  of the inner sleeve  32  of the longitudinal member  4 . The handle  6  may then be slid off of the cable  56  and the longitudinal member  4  may then be disengaged from the clamping mechanism  2  by removing the distal end  38  of the inner sleeve  32  from the slots  22  of the clamp  8  and the recess  34  of the outer sleeve  30  from the clamping ring  10 . The longitudinal member  4  may then be slid off of the cable  56 . 
     As shown in  FIG. 22 , the remaining cable  56  may then be cut as close to the clamping mechanism  2  as desired so that only the clamping mechanism  2  remains, projecting out slightly from the dorso-lateral side  46  of the bone  42 . As shown in  FIG. 23  and as would be understood by those skilled in the art, additional brim screws  74  may be inserted through an additional brim plate  76  to enhance the stability and support of the bone fragments. 
     As shown in  FIGS. 24-29 , an alternate embodiment of a clamping mechanism  100  comprises a clamp  102  and a clamping ring  104 . The clamping mechanism  100  may be used in the system, as described above, to secure the clamp  102  about the cable  56 , at a desired location. The clamp  102  is engagable with the clamping ring  104  to move a mandrel  106  of the clamping ring  104  from a first configuration in which the mandrel  106  permits the cable  56  to slide through the clamping mechanism  100  to a second configuration in which the mandrel  106  crushed against the cable  56  such that the cable  56  is fixed at a desired location. 
     The clamp  102  includes a head  108  and a body  110  extending distally from a distal end  112  of the head  108  to a distal end  114 . The clamp  102  further includes a lumen  116  extending longitudinally therethrough sized to slidably accommodate the cable  56 . The head  108  may be sized and shaped to engage a portion of the longitudinal member  4  such that the longitudinal member  4  may move the clamp  102  relative to the clamping ring  104 . In a preferred embodiment, the head  108  may be hexagonally shaped to mate with a correspondingly shaped distal end  38  of the inner sleeve  32  of the longitudinal member  4 . It will be understood by those of skill in the art that the distal end  38  of the inner sleeve  32  may be a hexagonally shaped recess to accommodate the head  108  of the clamp  102  or any other shaped protrusion or recess so long as the distal end  38  of the inner sleeve  32  mates with the head  108 . The body  110  of the clamp  102  may be sized and shaped to engage with the clamping ring  104 . The body  110  may include a threading (not shown) about an outer surface  118  thereof. It will be understood by those of skill in the art, however, that the body  108  may include any arrangement or mechanism for engaging with the clamping ring  104 . In the embodiment shown, a diameter of the body  110  may be larger than a diameter of the head  108 . However, it will be understood by those of skill in the art, that the body  110  may be any size or shape so long as the body  110  is engagable with the clamping ring  104 . 
     As described above, the clamping ring  104  is engagable with at least a portion of the body  110  of the clamp  102  and may be formed as, for example, a nut. The clamping ring  104  includes a channel  120  extending longitudinally therethrough for accommodating the cable  56 . The channel  120  may include a first portion  122  and a second portion  124  proximal of the first portion  122 . The first portion  122  may be sized and shaped to slidably accommodate the cable  56 . Thus, a size of the first portion  122  may be only slightly larger than a size of the cable  56 . The second portion  124  may be sized and shaped to accommodate at least a portion of the body  110 . Thus, an inner diameter or size of the second portion  124  will be larger than an inner diameter of the first portion  122 . The second portion  124  may include a threading (not shown) along an inner surface  126  thereof for rotatably engaging with the threading of the body  110 . However, it will be understood by those of skill in the art that the clamping ring  104  may include any mechanism or arrangement for engaging with the clamp  102 . An outer surface  128  may be shaped such that the clamping ring  104  may mate with the outer sleeve  30  of the longitudinal member  4 . For example, the outer surface  128  may be hexagonally shaped to mate with the hexagonal recess  34  of the outer sleeve  30 . Thus, it will be understood by those of skill in the art that when the inner sleeve  32  is rotated relative to the outer sleeve  30 , the clamp  102  will rotate relative to the clamping ring  104  such that the clamp  102  engages the clamping ring  104 . 
     The mandrel  106  may be substantially longitudinally shaped and positioned within the clamping ring  104  such that the mandrel  106  is movable from the first configuration, shown in  FIGS. 24 ,  26  and  28 , to the second configuration, shown in  FIGS. 25 ,  27  and  29 . The clamping ring  104  includes a slot  130  extending laterally therethrough for accommodating the mandrel  106  such that a length of the mandrel  106  is housed within the channel  120  of the clamping ring  102 . The slot  130  is elongated such that a proximal end  132  of the slot  130  accommodates the mandrel  106  in the first configuration while a distal end  134  of the slot  130  accommodated the mandrel  106  in the second configuration. The slot  130  is angled such that the proximal end  132  passes through the second portion  124  of the channel  120  and is radially outward of the first portion  122 . Thus, in the first configuration, the mandrel  106  does not interfere with the slidable insertion of the cable  56 . The slot  130  angles radially inward from the proximal end  132  toward the distal end  134  such that the distal end  134  is at least partially within the first portion  122 , interfering with the channel  120 . Thus, the mandrel  106  may slide from the proximal end  132  in the first configuration to the distal end  134  in the second configuration to crush the cable  56  passing through the channel  120 , thereby fixing the cable  56 . 
     The mandrel  106  may be moved from the first configuration to the second configuration as the clamp  102  engages the clamping ring  104 . The distal end  114  of the clamp  102  abuts the mandrel  106  such that as the clamp  102  is moved relative to the clamping ring  104  to engage with the clamping ring  104 , the distal end  114  moves the mandrel  106  distally relative to the clamping ring  104 . Thus, the mandrel  106  slides from the proximal end  132  of the slot to the distal end  134  of the slot  130 , crushing the cable  56  within the first portion  122  of the channel  120 . 
     It will be apparent to those of skill in the art that various modifications and variations can be made in the structure and the methodology of the present invention, without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided that they come within the scope of the appended claims and their equivalents.