Abstract:
A surgical cable crimp device including a cable with a fixed and a free end and a crimp member for securing the cable. The crimp member has a first leg having a blind hole for receiving the fixed end of the cable, and a second leg with a through bore extending through the second leg for receiving the free end of the cable, the first and second legs connected in the front by a front bridging portion and in the back by a rear bridging portion. The rear bridging portion is longer than the front bridging portion so that the crimp member has a wedge-shape and the second leg is crimpable so that the cable is crimped to the crimp member after the free end is inserted in the through bore.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to an orthopedic instrument in general, and in particular to a fastening or crimping device for use with surgical cables in fixation of bones during surgeries for fractured bone or bone reconstruction. 
     BACKGROUND OF THE INVENTION 
     In surgical and orthopedic operative techniques, it is frequently necessary to fix bone parts, which have been separated surgically or because of fracture, in an exact mutual position and to join them together under pressure. Surgical cable and crimp assemblies are frequently used for this purpose. The cables are used to encircle the bone, or bone and plate, to provide for fixation. In fixation by cable, it is customary to use a fastening device, typically a crimp device which is adapted to be deformed upon the cable for securing the cable in place, encircling the bone in the fracture area. Such assemblies can be subjected to very high tensile forces when, for example, the fractured bone is subjected to a high bending moment. It is therefore important that the cable and crimp assembly have sufficient strength to prevent cable failure under tensile force. 
     Typically, the cable must be used in a subcutaneous confined area. Thus it is important that the cable and crimp assembly be easy to assemble in such a restricted area. For instance it is desirable to have a device which allows the cable to pass easily through the crimp member to prevent kinking and possible fraying of the cable where it enters the crimp member. Also it is advantageous to have easy access to the crimp device to facilitate crimping. Easy cable access is also desirable to provide room for the application of a tension tool to tighten the cable around the bone. Furthermore, it is desirable to maintain the bulk of the cable as well as the joint where the cable is affixed to itself as compact as possible to minimize discomfort to the patient and damage to the surrounding tissue. 
     A wide variety of devices for crimping a surgical wire are known in the art. Examples of such crimp devices include those described in U.S. Pat. No. 5,810,825 issued to Huebner, U.S. Pat. Nos. 5,868,748 and 5,720,747 to Burke. Although these devices are quite successful from a technical point-of-view in achieving the desired crimping of surgical wire, most of existing devices have practical limitations. For example, most crimping devices maintain the surgical wire or cable parallel to itself in the fastening or crimping member which makes it difficult to access the free end of the cable and tighten around the bone. In addition, some crimping devices require that the entire fastening or crimping member be crimped in order to secure the surgical wire thereto, necessitating a larger access area to permit a crimping tool to access the entire fastening or crimping member. 
     Other crimp devices exist which are substantially “L” shaped and maintain the surgical wire or cable at a 90° angle to itself as it leaves the fastening or crimping member. Maintaining the cable at such a steep angle can put a kink in the cable at that location and increase the likelihood that the cable will break. Furthermore, when the crimping member maintains the cable at a 90° angle, it is more difficult to insert the cable through the crimp member. 
     Thus, there exists a need for an improved surgical crimp device that is compact, sufficiently strong, and easy to assemble in a confined area. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a surgical fastener device for fixing bone elements comprising a flexible cable having first and second ends attached to a crimp member. The crimp member has first and second portions extending between front and rear ends. First and second portions are spaced farthest apart at the rear end to form a wedge-shaped. Additionally, a channel extends through the second portion. The first end of the cable is fixedly secured to the first portion at the rear end, and the second end of the cable is insertable through the channel of the second portion for forming a loop of adjustable diameter. 
     In one embodiment, the front and rear ends of the crimp member are rounded and the front end of the crimp member can have a smaller arc length than the rear end. 
     In another embodiment, the front end of the crimp member is solid and the rear end has a longitudinal slot. 
     In yet another embodiment, the crimp member has an open central portion that forms a substantially triangular cutout. 
     In an alternative embodiment, the second end of the cable has a leader to facilitate handling. 
     In an additional embodiment, the cable is multi-stranded. 
     In another embodiment, the first and second portions of the crimp member are coplanar. 
     The present invention is further directed to a surgical fastener device for crimping surgical cable. The device includes a crimp member comprising a wedge-like body having first and second parallel major surfaces vertically interconnected by a peripheral edge. The body has a centrally disposed triangular opening vertically extending through the body from the first major surface to the second major surface. The body also has a pair of channels extending longitudinally through the body. The channels are disposed at a non-parallel angle with respect to each other. 
     In an alternative embodiment, the device further includes a flexible cable secured to one of the channels of the crimp member. The cable has first and second ends and one end is fixedly attached to the crimp member and the other end is insertable through the other channel for forming a loop of adjustable diameter. The cable can be multi-stranded and the insertable end can have a leader to facilitate handling. 
     The present invention is also directed to a surgical fastening device comprising a cable having a free end and a fixed end attached to a crimp member. The crimp member has a first leg with first and second ends. The first end has a blind hole for receiving the fixed end of the cable. The crimp member also has a second leg with first and second ends. The second leg has a through bore extending from the first end to the second end of the second leg. The crimp member also has a front bridging portion connecting the second end of the first leg to the second end of the second leg. The crimp member also has a rear bridging portion connecting the first end of the first leg to the first end of the second leg. The rear bridging portion is longer than the front bridging portion so that the crimp member has a wedge-shape. The second leg is crimpable so that the cable is crimped to the crimp member after the free end is inserted in the through bore. 
     In another embodiment, the cable is multi-stranded and the free end has a leader to facilitate handling. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of a surgical crimp device according to the present invention showing a flexible cable and a crimp member; 
     FIG. 2 is a perspective view of the crimp member of FIG. 1 prior to assembly with the cable; 
     FIG. 3 is a top view of the crimp member of FIG. 2 with a cutaway showing cross sections of internal channels therein; 
     FIG. 4 is a front view of the crimp member of FIG. 2; 
     FIG. 5 is a back view of the crimp member of FIG. 2; 
     FIG. 6 is a magnified view of FIG. 1 with an enlargement of the first end of the cable; 
     FIG. 7 is a side view of the surgical crimp device of FIG. 1 after the device has been crimped around a bone; 
     FIG. 8 is a side view of the surgical crimp device of FIG. 7 showing the crimp member in a low profile position; 
     FIG. 9 is a top view of the surgical crimp device of FIG. 8; 
     FIG. 10 is a side view of the crimp member of FIG. 2; 
     FIG. 11 a top view of an alternative embodiment of the surgical crimp device; 
     FIG. 12 is a perspective view of an alternative embodiment of the crimp member; 
     FIG. 13 is a top view of the crimp member of FIG. 9 with a cutaway showing cross sections of the internal channels therein; and 
     FIG. 14 is a perspective view of the crimp member of FIG. 9 showing a cable extending therethrough; 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in FIG. 1, a surgical crimp device  10  according to the present invention includes a crimp member  20  and a flexible cable  50 . Cable  50  can be either a single strand wire or a multi-wire stranded cable. A first end  51  of the cable is fixedly attached to crimp member  20  and a second end  52  of the cable is a free end. 
     As best seen in FIGS. 2-5, crimp member  20  preferably has a wedge-shape with a generally triangular perimeter. For ease in handling, the corners are rounded or smoothed rather than meeting at sharp points. The crimp member preferably has a planar top surface  31 , a spaced parallel planar bottom surface  32 , and a perimeter surface  30  extending vertically therebetween. Perimeter surface  30  has two sidewall sections  33  and  34 , a front wall section  35 , and a base wall section  36 . Sidewall sections  33  and  34  are displaced at a non-parallel angle with respect to each other. Preferably sidewall sections  33  and  34  are at an acute angle with respect to each other. Sidewall sections  33  and  34  are connected by a rounded front wall section  35  at the front end or vertex. At the back end or base, the two sidewall sections are connected by a rounded base wall section  36 . The rounded base wall section preferably has a larger radius of curvature than front wall section  35 . 
     Crimp member  20  preferably has a vertical cutout  24 . In the preferred embodiment vertical cutout  24  is generally triangular. Preferably cutout perimeter surface  45  is similar to the crimp member perimeter surface  30  such that cutout  24  has side sections  37  and  38  which are parallel to the perimeter sidewall sections  33  and  34  respectively. The cutout side sections are connected at the front end or apex by a rounded front section  39  and at the back end or base by a rounded base section  40 . The rounded base section  40  of the cutout preferably has a larger radius of curvature than the front section  39 . 
     In the embodiment shown in FIGS. 2-5, cutout side section  37  and perimeter sidewall section  33  together define a first leg  25 . Cutout side section  38  and perimeter sidewall section  34  together define a second leg  26 . Cutout front section  39  and perimeter front wall section  35  together define a nose section  41 . Cutout base section  40  and perimeter base wall section  36  together define a bridge section  42 . Nose section  41  at the front end is preferably solid and bridge section  42  at the back end preferably has a longitudinal slot  23  extending therethrough. Thus, crimp member  20  has first leg  25  and second leg  26  which are attached at the front end by nose section  41  and extend longitudinally from the front end of crimp member  20  to the back end or base at a non-parallel, preferably acute, angle. First and second legs  25 ,  26  are spaced farthest apart at the back end. First and second legs  25 ,  26  are horizontally connected at the back end by bridge section  42 . 
     First leg  25  has an internal blind channel  27  extending longitudinally therein for receiving first end  51  of cable  50 . Channel  27  preferably has one opening located at perimeter base wall section  36  located at the back end of crimp member  20 . Preferably blind channel  27  is cylindrical with a longitudinally extending central axis parallel with perimeter sidewall section  33  and cutout side section  37 . Second leg  26  has a through channel  29  for receiving second end  52  of cable  50 , which extends longitudinally through the entire second leg. Through channel  29  has a front opening  21  at perimeter front wall section  35  and a base opening  22  at the perimeter base wall portion  36 . Preferably, through channel  29  is cylindrical with a longitudinally extending central axis disposed parallel to perimeter sidewall section  34  and side section  38  of vertical cutout  24 . In FIG. 3, portions of crimp member  20  are broken away to show the internal channels  27  and  29  of the first leg  25  and second leg  26  respectively. The longitudinally extending central axes of these channels are coplanar. First and second legs  25  and  26  have a thickness slightly larger than the diameter of cable  50  so as to allow cable  50  to be inserted therethrough. 
     Referring to FIG. 6, first end  51  of cable  50  is fixedly attached to crimp member  20 . Any suitable means for securing first end  51  of cable  50  to crimp member  20  can be used, such as gluing, welding, swaging, etc. Preferably, first end  51  of cable  50  is inserted in blind channel  27  of first leg  25  and cable  50  is swaged to the channel to permanently secure first end  51  of cable  50  to crimp member  20 . Second end  52  of cable  50  has a leader portion  53  welded thereto to facilitate handling of cable  50  and entrance of second end  52  into through channel  29  of second leg  26  during operation. 
     In order to use the surgical crimp device to secure a cable around a bone, the surgeon first prepares the area by exposing the patient&#39;s bone. Referring to FIGS. 7-9, the crimp member is placed against a bone  60  to be mended and second end  52  of the cable is wrapped around bone  60 . Second end  52  of cable  50  is then inserted in through channel  29  of crimp member  20 . The cable preferably enters channel  29  through front opening  21  and exits channel  29  through base opening  22 , however, the cable can be inserted in through channel  29  in a reverse manner. Initially sidewall section  33  is preferably placed tangent to bone  60  so that crimp member  20  is resting on first leg  25  and second leg  26  is angled away from bone  60 . When cable  50  is inserted in through channel  29  and second end  52  exits base opening  22 , second end  52  is angled away from bone  60  and toward a surgeon allowing the cable to angle away from the bone is particularly advantageous because second end  52  is easier to access by a tensioning tool. Second end  52  of cable  50  is then pulled to bring cable  50  taut around bone  60  with the aid of a conventional tensioning tool which is not shown in the drawings. When the desired tension is achieved, second leg  26  is crushed with pliers or a similar crimping instrument as are known in the art. It is particularly advantageous that second leg  26  is angled away from bone  60  to allow greater access for a crimping instrument in a confined area. In addition, because only a portion of crimp member  20  is crushed, here second leg  26 , less force is required than crushing the entire crimp member. When second leg  26  is crushed, through channel  29  is deformed or constricted, preventing movement of cable  50  therethrough to secure the cable within through channel  29  under tension. Any excess cable that extends beyond the back end can then be cut and removed. 
     As shown in FIGS. 8 and 9, crimp member  20  can be pushed over to lay flat after crimping second leg  26 , placing either top planar surface  31  or bottom planar surface  32  in contact with bone  60 . As a result, the profile of the crimp device in the body is reduced. For example, after legs  25  and  26  are crimped and crimp member  20  is pushed over to lay flat, the resulting thickness of crimp member  20  is preferably not substantially thicker than the radius of cable  50 . 
     Although cable  50  is shown as a multi-strand wire, the invention can be used with any type of surgical cable, such as a single strand wire. Preferably, the cable used with the proposed crimp is a multi-wire stranded cable. Crimp member  20  and cable  50  are preferably titanium although they may be manufactured from any material suitable for surgical procedures. 
     Referring to FIG. 10, preferably an arrow, symbol or other indicia is etched on the outside of the second leg to illustrate the preferred direction to insert second end  52  of cable  50  in the through channel  29 . 
     Referring to FIG. 11, another embodiment of the present invention includes a cable  80  having a crimp member as previously described attached on each end. A leader portion  81  is welded onto the cable at the longitudinal center of the cable. When a crimp device, cable  80  is cut in the center of leader portion  81  to yield two identical crimp devices according to the present invention. This embodiment of the present invention provides for efficient manufacturing and storage of the crimp devices. 
     Referring now to FIGS. 12-14, an alternative embodiment of the crimp member has two leg members, first leg  61  and second leg  62 , arranged in a generally triangular configuration and attached at the front end or vertex. Leg members  61  and  62  are preferably displaced at a non parallel angle with respect to each other. Preferably leg members  61  and  62  are displaced at an acute angle with respect to one another. Legs  61  and  62  are connected horizontally by a web section  63 . In this embodiment, legs  61  and  62  are substantially cylindrical with concentric channels therein. First leg  61  has a blind concentric channel  64  extending longitudinally therein. Blind channel  64  has one opening at the back end of the crimp member. Second leg  62  has a concentric through channel  65  extending through the entire length of leg  62 . Through channel  65  has one opening at the back end and one opening at the front end. A conical chamfer  66  surrounds the openings of channels  64 ,  65  to guide the entrance of the cable into the channels. 
     While it is apparent that the illustrative embodiments of the invention herein disclosed fulfill the objectives stated above, it will be appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments which come within the spirit and scope of the present invention.