Patent Publication Number: US-2021177475-A1

Title: Cable saddle

Description:
PRIORITY CLAIM 
     The present application is a Continuation application of U.S. patent application Ser. No. 15/818,262 filed on Nov. 20, 2017; which claims priority to U.S. Provisional Patent Application Ser. No. 62/431,638 filed on Dec. 8, 2016; the entire disclosure of the above application(s)/patent(s) is expressly incorporated herein by reference. 
    
    
     BACKGROUND 
     Bones are often treated using cerclage techniques in which a wire or other cable is wrapped around a portion of bone to facilitate fixation or repair thereof Cerclage procedures generally involve looping a wire or cable around the bone to be repaired. In some cases, typically in periprosthetic fractures, the cable has a tendency to subside into osteoporotic bone, causing the loosening of the overall construct. In these instances, it may be necessary to replace the wire or cable with a new cable system. Sometimes these procedures have to be repeated with second or third replacement procedures being required. Thus, there is a need for a cable instrument or implant that prevents cerclage cables from subsiding into bone while offering a value-added upgrade to existing customers who may not be willing to undergo replacement of a subsided cable with a completely new cabling system. 
     SUMMARY 
     The present embodiments relate to a cerclage system and method for stabilizing fractures using either a cable saddle or a cable belt in addition to a cerclage cable. 
     In one aspect, a fracture stabilization device according to an exemplary embodiment includes a body extending from a first end to a second end along a longitudinal axis, the body defining an upper surface and a bone facing surface and including a first loop extending from the surface at the first end and a second loop extending from the upper surface a second end. The first and second loops include apertures extending therethrough sized and shaped to receive a cerclage cable therethrough. The upper surface includes a plurality of elongated reliefs extending transverse to the longitudinal axis of the body to facilitate bending of the body along its longitudinal axis to conform to a contour of a target portion of bone over which the fracture stabilization device is to be mounted. In one embodiment, the upper surface includes a groove extending from the first loop to the second loop and open to the apertures. In another embodiment, the bone facing surface includes a plurality of ridges. In a further embodiment the body includes a plurality of holes extending from the bone facing surface to the upper surface. In yet another embodiment, the plurality of reliefs is open to at least one of the plurality of holes. 
     In another aspect, a system for securing a target portion of bone includes an elongated cerclage cable extending from a proximal end to a distal end and configured to circle the target portion of bone. The system also includes a cable link comprising an upper surface and a bone-facing surface and extending from a first end to a second end. The cable link includes a through-hole extending therethrough from the first end to the second end, the through-hole sized and shaped to receive the cerclage cable therethrough. The first end includes a first coupling member and the second end includes a second coupling member such that the first coupling member of a first cable link is configured to couple to the second coupling member of an adjacent second cable link so that the through-holes of the first and second cable links align to form an elongated cerclage cable passageway. In an embodiment, the first coupling member includes a rounded protrusion configured to be slidably received by the second coupling member. In another embodiment, the second coupling member is formed as a C-shaped extension configured to slidably receive the first coupling member therein. In a further embodiment, the bone-facing surface includes a plurality of ridges. In a further embodiment, the system includes an elongated bone plate configured to be attached to a target portion of bone. In another embodiment, the system further includes a third cable link, wherein the first coupling member of the third cable link is configured to couple to the second coupling member of the second cable link such that the first, second and third cable links form a cable belt. In another embodiment, the system further includes a cable crimp coupled to the proximal end of the cerclage cable. In a further embodiment, the first and second coupling members are hooks. In another embodiment, the first and second cable links are pivotable relative to one another. 
     In another aspect, a method for securing a target portion of bone includes making an incision adjacent to the target portion of bone and passing a cerclage device through the incision and around the target portion of bone. The cerclage device includes a cable link including an upper surface and a bone-facing surface and extending from a first end to a second end. The cable link includes a through-hole extending therethrough from the first end to the second end, the through-hole sized and shaped to receive a cerclage cable therethrough. The first end includes a first coupling member and the second end includes a second coupling member. The cerclage device also includes an elongated cerclage cable slidably disposed within the through-hole, the elongated cerclage cable extending from a proximal end to a distal end and configured to circle the target portion of bone. The method also includes applying tension to a distal end of the cerclage cable to pull the cerclage device into a target position about the bone. The method also includes locking the cerclage device in the target position about the target portion of bone. In one embodiment, the first coupling member of a first cable link is configured to couple to the second coupling member of an adjacent second cable link such that the through-holes of the first and second cable links align to form an elongated cerclage cable passageway. In an embodiment, the first and second cable links are pivotable relative to one another. In another embodiment, the cerclage device includes a third cable link, wherein the first coupling member of the third cable link is configured to couple to the second coupling member of the second cable link such that the first, second and third cable links form a cable belt. In a further embodiment, the first coupling member is formed as at least one rounded protrusion configured to be slidably received by the second coupling member. In another embodiment, the second coupling member is formed as at least one C-shaped extension configured to slidably receive the first coupling member therein. 
    
    
     
       BRIEF DESCRIPTION 
         FIG. 1  shows a perspective view of a cable saddle system according to an exemplary embodiment; 
         FIG. 2A  shows a perspective view of a cable saddle according to an exemplary embodiment; 
         FIG. 2B  shows a top view of the cable saddle of  FIG. 2A ; 
         FIG. 2C  shows a bottom view of the cable saddle of  FIG. 2A ; 
         FIG. 2D  shows a side view of the cable saddle of  FIG. 2A ; 
         FIG. 2E  shows a front view of the cable saddle of  FIG. 2A ; 
         FIG. 3  shows another side view of the cable saddle of  FIG. 2A ; 
         FIG. 4  shows a side view of the cable saddle and cable of the cable saddle system of  FIG. 1 ; 
         FIG. 5A  shows a perspective view of a cable saddle according to a second exemplary embodiment; 
         FIG. 5B  shows a side view of the cable saddle of  FIG. 5A ; 
         FIG. 6  shows a perspective view of a cable belt system according to an exemplary embodiment; 
         FIG. 7  shows a perspective view of a cable link of the cable belt system of  FIG. 6 ; 
         FIG. 8  shows a perspective view of a interlocked pair of cable links of the belt system of  FIG. 6 ; 
         FIG. 9  shows a perspective view of a cable belt of the cable belt system of  FIG. 6 ; 
         FIG. 10  shows another perspective view of the cable belt system of  FIG. 6 ; and 
         FIG. 11  shows a perspective view of a cable belt according to another exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The present embodiments may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The present embodiments relate generally to methods and devices for the stabilization and fixation of fractured bones and bone fragments via a minimally invasive cerclage belt system. In particular, the present embodiments relate to methods and devices for securing a bone plate against a target portion of bone using a cerclage cable and cable saddle. The present embodiments also contemplate a cerclage cable belt comprising a plurality of belt links. The present embodiments may also be employed with any of a plurality of treatment procedures involving cerclage. As used in the application, the terms proximal and distal refer to a direction along the cerclage cable with a first end of the cable being identified as the proximal end and a second end of the cable being identified as distal. Components of an exemplary cable saddle according to the present embodiments will be described in relation to the direction which the cable passes therethrough. For example, an opening to a lumen into which a distal end of the cable is inserted and against which a proximal end of the cable is held will be described as the proximal opening of the lumen. The opposite end of the lumen from which the distal end of the cable exits will be described as the distal opening of the lumen and the other elements of the saddle will be similarly identified. 
     As shown in  FIGS. 1-4 , a cable saddle system  100  according to a first exemplary embodiment comprises a saddle  102  for receiving a cable  10  to be looped around a bone plate  104  positioned on a target portion of bone  106 . The saddle  102  comprises a saddle body  108  including a first bone-facing surface  110  which may be flat or contoured to and a second upper surface  112  extending between a first end  114  a second end  116  substantially parallel to one another. The saddle  102  includes a first loop  118  extending from the upper surface  112  at the first end  114  and a second loop  120  extending from the upper surface  112  at the second end  116 . The first and second loops  118 ,  120  define first and second apertures  122 ,  124 , respectively, extending therethrough. The diameters of the first and second apertures  122 ,  124  are substantially equal to one another and are selected to permit slidable insertion of the cable  10  therethrough with minimal lateral movement of the cable  10  therein. Specifically, the diameter of the first and second apertures  122 ,  124  is substantially equal to an outer diameter of the cable  10  plus a small clearance to permit the cable  10  to slide smoothly therethrough. While two loops  118 ,  120  are used in the present embodiment, as would be understood by those skilled in the art that any number of loops may be used so long as the cable  10  is constrained to lie over the saddle  102  so that the portion extending between the apertures does not lie directly on the bone. In an exemplary embodiment, upper surface  112  includes a semi-circular groove  126  extending from the first loop  118  to the second loop  120  and open to apertures  122 ,  124  sized to receive the portion of the cable  10  extending between the apertures  122 ,  124 . The groove  126  holds the cable  10  in place to resist lateral movement of the cable  10  and helps the cable  10  to hold the saddle  102  against the target portion of bone  106  when cable tension is applied. The saddle  102  further includes a plurality of holes  128  extending from the bone-facing surface  110  to the upper surface  112 . The holes  128  allow bony and soft tissue ingrowth into the saddle  102  to enhance long-term fixation and stability of the position of the saddle  102  on the bone while also reducing material mass. In an exemplary embodiment shown in  FIGS. 2A-2C , six circular holes  128  are used. However, as those skilled in the art will understand, any shape and a number of holes  128  may be used so long as the structural integrity of the saddle  102  is maintained. For example, in another exemplary embodiment shown in  FIG. 5A  four elongated holes  128 ′ are shown. The upper surface  112  includes a plurality of cutouts or reliefs  130  extending generally transverse to the groove  126  (i.e., transverse to a longitudinal axis L of the saddle  102 ). The reliefs  130  allow the saddle  102  to bend and flex to more easily conform to the contour of the target bone  106 , as can be seen in  FIGS. 3-4 . In an exemplary embodiment, the reliefs  130  overlap with the holes  128  to further enhance the flexibility of the saddle  102  and to reduce material mass. It will be understood that any number of reliefs  130  may be used. For example, as can be seen in  FIG. 2B , three reliefs  130  are disposed on the upper surface  112  extending transverse to the longitudinal axis L of the saddle  102  and passing over two holes  128  each, one hole  128  on either side of the longitudinal axis L of the saddle body  108 . It will be understood by those skilled in the art that any configuration of reliefs  130  and holes  128  may be used as necessary to achieve the desired flexibility of the saddle  102 . As shown in  FIGS. 2C-2D , the bone-facing first surface  110  includes ribs or ridges  132  extending therefrom to increase a grip of the saddle body  108  on the bone and to prevent undesired movement of the saddle body  108  relative to the target bone  106  after the saddle body  108  has been placed in a desired position. 
     As would be understood by those skilled in the art, the saddle body  108  may be formed to include the loops  118 ,  120 , groove  126 , holes  128 , reliefs  130  and ridges  132  using conventional manufacturing methods such as welding, pressing, electrical discharge machining, casting, machining and/or forging. Saddle  102  may be formed of a metal such as stainless steel or titanium. Additionally, the bone-facing surface  110  may be coated or further roughened to enhance the grip of the saddle  102  on the target bone  106 . 
     In an exemplary method, target portions of bone (not shown) are initially moved relative to one another into a desired corrective position (e.g. by reducing a fracture) prior to insertion of the cable  10  and the saddle  102  to desired positions relative to the target portions of bone. In an exemplary embodiment, once the target portions of bone have been positioned as desired, a bone plate  104  may be inserted (e.g., through a minimally invasive incision adjacent to the target portions of bone  106 ) and fixed to the target portions of bone to maintain the target portions of bone in a desired spatial arrangement. In another exemplary embodiment, no bone plate is used. Once the bone plate  104  has been positioned as desired, the cable  10  may then be inserted through the same minimally invasive incision and wound around the target portions of bone  106  to further stabilize the positions of the target portions of bone. The distal end of the cable  10  is then threaded through the first and second loops  118 ,  120  of the cable saddle  102  and the cable  10  is used to move the saddle  102  over the bone to a desired position. In an exemplary embodiment, the saddle  102  is positioned on a surface of the bone opposite the bone plate  104 , as seen in  FIG. 1 . When the cable  10  is tightened around the target bone  106 , the saddle  102  increases the surface area over which the compressive force from the cable  10  is exerted on the bone reducing the risk that the cable  10  will dig or subside into the bone. The cable  10  is then tensioned to a desired level as would be understood by those skilled in the art so that a desired force is applied to the bone. As the desired force is being applied to the cable  10 , the cable  10  compresses the first and second ends  114 ,  116  of the saddle body  108  against the bone  106 , bending the saddle body  108  to adapt to a contour of the bone  106 . The cable  10  is then locked in place using, for example, a cable crimp  134 . After the cable  10  has been locked in place, any extra length of the cable  10  extending from the crimp  134  is cut. It will be understood by those skilled in the art that multiple cables  10  and cable saddle  102  may be used to treat the fractured bone. 
     As shown in  FIGS. 5A and 5B , a system  100 ′ according to an alternate embodiment is substantially similar to the system  100  described above, comprising a cable saddle  102 ′ including a body  108 ′ having two loops  118 ′,  120 ′ through which a cable (not shown) is slidably received. The configuration of the cable saddle  102 ′ is the same as that of the cable saddle  102  except, rather than having a substantially flat body, saddle body  108 ′ is pre-contoured to conform to a shape of the outer surface of the target bone (not shown). Specifically, the saddle body  108 ′ is curved along its length from a first end  114 ′ to a second end  116 ′ such that first bone-facing surface  110 ′ has a radius of curvature, R, corresponding generally to a contour of a target surface of the bone. Because the saddle  102 ′ is pre-contoured to match a contour of a surface of the bone, the increased flexibility of the saddle body  108  is not as critical to the functioning of the saddle body  108 ′. Thus, the upper surface  112 ′ of the embodiment shown in  FIGS. 5A-5B  does not include the reliefs in upper surface  112 ′ as were present in the saddle body  108 . However, it will be understood that cable saddle  102 ′ may include reliefs if further bending and/or flexibility of the cable saddle  102 ′ is required. 
     As shown in  FIGS. 6-10 , a cable belt system  200  according to an exemplary embodiment comprises a plurality of cable links  240  for receiving an elongated cerclage cable  20  to be looped around a bone plate  204  positioned on a target portion of bone  206 . Each cable link  240  includes a body  208  extending along a longitudinal axis from a first end  214  to a second end  216  and having a first bone-facing surface and a second surface connected by four side-walls  242 ,  244 ,  246 ,  248 . A central longitudinal through-hole  250  extends through the cable link body  208  along the longitudinal axis from a first side wall  242  to a second side wall  246 . The diameter of the through-hole  250  is selected to permit slidable insertion of the cerclage cable  20  therethrough with minimal lateral movement of the cable  20  within. Specifically, the diameter of the through-hole  250  is substantially equal to an outer diameter of the cable  20  plus a small clearance to permit the cable  20  to slide smoothly therethrough. Each cable link  240  is configured to interlock with one or more other cable links  240 ′ through a male connector  252  at first end  214  and a female receiving connector  254  at second end  216 . Specifically, the cable link  240  includes a male connection portion  252  comprising a pair of protrusions  256  extending from a first end  214  of the body  208 . The protrusions  256  are positioned on either side of the central through-hole  250  and extend from a first side wall  242 . Each of the protrusions  256  includes a connecting portion  258  and a rounded head portion  260 . Each head portion  260  in this embodiment is substantially cylindrical and extends along an axis substantially perpendicular to the longitudinal axis of the cable link  240 . Each rounded head portion  260  is sized to laterally slide into a corresponding rounded receiving space  262  of a female connection portion  254 , as shown in  FIG. 8 . That is, the diameters of rounded head portions  260  are selected to permit slidable insertion of the head portions  260  into the female connection portion  254 . 
     The female connection portion  254  comprises a pair of C-shaped extensions  264  extending from the second end  216  of the body  208 . The extensions  264  are positioned on either side of the central through-hole  250  and include an upper curved portion  266  and a lower curved portion  268  extending from second side wall  244  to define the receiving space  262  therebetween. When connected with the protrusions  256  of a second cable link  240 , the upper and lower curved portions  266 ,  268  extend substantially around the head portion  260  of the protrusions  256  such that the protrusions  256  are unable to be pulled out of the receiving space  262 . The diameter of the receiving space  262  is selected to permit slidable insertion of the protrusions  256  of the male connection portion  252  therethrough while also allowing the protrusions  256  to pivot in a plane perpendicular to the longitudinal axis of the cable links  240 . Specifically, the diameter of the receiving space  262  is substantially equal to an outer diameter of the protrusions  256  plus a small clearance to permit the protrusions  256  to slide smoothly therethrough and pivot while held within the extensions  264 . The cable links  240  are configured such that, when two or more links  240  are coupled to one another, the through-holes of each adjacent cable link  240  align with one another to form an elongated passageway for the cable  20 . In an operative configuration, a distal end  22  of the cable  20  is inserted through a proximal end of a first through hole  250  and drawn distally through each of the interlocked cable links  240 . The cable  20 , once threaded through each cable link  240 , further prevents uncoupling of the cable links  240  by limiting lateral movement of the links  240  relative to one another while a series of cable links  240  may then hold the entire circumference of the cable  20  out of contact with the bone. 
     As shown in  FIGS. 7-8 , the bone-facing first surface  210  includes ribs or ridges  232 , similar to the ridges  132 , to increase grip against the bone and to prevent movement when in contact with the target bone  206  while also increasing contact surface area to prevent the links  240  from sinking into the bone  206 . 
     In an exemplary method, a number of cable links  240  selected to extend around a desired portion of a circumference of a target portion of bone are initially linked together by sliding each of the male connector portion  252  through the receiving portions  262  of the female connector portion  254  to create a chain, or belt,  270  of cable links  240 . Once the desired number of cable links  240  has been coupled together, distal end  22  of cable  20  is inserted through each of the adjacent through-holes  250  of the interlocked cable links  240  prior to surgery. In an exemplary embodiment, a proximal end  24  of the cable  20  includes an increased diameter stop member (not shown) at a proximal end to prevent the cable links  240  from sliding off of the cable  20 . In another exemplary embodiment, the proximal end  24  of the cable  20  includes a cable crimp  234  preventing the cable links  240  from sliding off of the cable  20 . During surgery, as those skilled in the art will understand, target portions of bone (not shown) are moved relative to one another into a desired corrective position (e.g., by reducing the fracture) prior to insertion of the cable  20  and cable links  240  into the body. In an exemplary embodiment, once the target portions of bone have been positioned as desired, a bone plate  204  is inserted through a minimally invasive incision adjacent to the target portions of bone  206  and fixed to the target portions of bone to fix these portions of bone in a desired spatial relation to one another. In another exemplary embodiment, no bone plate is used. Once the bone plate  204  is in position, the distal end  22  of the cable  20  is inserted through the same minimally invasive incision and wound around the target portions of bone  206  to hold the bone together. As the cable  20  is wound about the target bone  206 , the cable  20  tows the cable link belt  270  around the target bone  206  so that the further cable  20  is pulled around the bone, the further the cable belt  270  is also pulled about the bone towards a target position encircling a target circumference of the target bone  206 . In an exemplary embodiment, the cable belt  270  extends over a target portion of a surface of the bone (e.g., a portion diametrically opposite the bone plate  204 ) as can be seen in  FIG. 6 . Thus, as the cable  20  is tightened around the target bone  206 , the cable belt  270  holds this portion of the cable  20  out of direct contact with the bone and spreads the compressive force exerted by the cable  20  over a larger surface area preventing the cable  20  from digging or subsiding into the bone. The cable  20  is tensioned to a desired level as would be understood by those skilled in the art to apply a desired compressive force to the bone. As the desired force is being applied to the cable  20 , the cable  20  presses the cable belt  270  against the target bone  206 , causing the male connection portions  252  to pivot within the female connection portions  254  so that the cable belt  270  contours to the shape of the bone  206 . The cable  20  is then locked in place using, for example, a cable crimp  234 . After the cable  20  has been locked in place at the desired tension, any extra length of the cable  20  extending from the crimp  234  is cut. It will be understood by those skilled in the art that multiple cable belts  270  of varying lengths may be used to treat the fractured bone, as shown in  FIG. 10 . 
     As shown in  FIG. 11 , a cable belt system  300  according to a further embodiment is substantially the same as system  200  described above, comprising a cable belt  370  formed of a plurality of cable links  340  coupled together at connection portions  352 ,  354 . However, in this embodiment, the connection portions are configured as interlocking hooks  380 ,  382  extending from each of the first and second side walls  342 ,  344 . A first hook  380  extends from first side wall  342  adjacent to the bone-facing surface  310  towards the upper surface  312  while the second hook  382  extends from the second side wall  344  adjacent to the upper surface  312  toward the bone-facing surface  310  such that, the links  340  are coupled to one another by interlocking the first and second hooks  380 ,  382 , as shown in  FIG. 11 . Each of the hooks  380 ,  382  includes a substantially semi-circular cutout  384  which aligns with a corresponding through-hole  350  of the cable link  340  to allow free passage of the cable  30  through links  340 . Specifically, the cutouts  384  are sized to be equal to an outer diameter of the cable  30  plus a small clearance to permit the cable  30  to slide smoothly therethrough. As would be understood by those skilled in the art, the connection portions  352 ,  354  of the cable links  340  may be configured in any other suitable way to allow free passage of the cable  30  and pivoting movement of the cable links  340  relative to one another so to permit the cable belt  370  to conform to the shape of an outer surface of the target portion of bone when the cable  30  is tightened therearound. 
     It will be apparent to those skilled in the art that various modifications and variations may be made in the structure and the methodology of the present embodiments, without departing form the spirit or scope of the embodiments. Thus, it is intended that the present embodiments cover modifications and variations provided that they come within the scope of the appended claims and their equivalents.