Patent Abstract:
An orthopedic bone plate constructed from shape memory material provides the ability to move from an open shape to a compressed shape and create compression on two bones or bone fragments to encourage healing. The plate may be any umber of shapes, with two or more screws anchoring the plate to bone. The plate is affixed to bone in a sequence of steps that involve first placing the plate on an insertion tool, attaching drill guide tubes, placing the plate over bone, drilling holes in bone, and then attaching the plate to the bone via screws. The insertion tool can then be removed at the surgeon&#39;s convenience allowing compression on the two bones.

Full Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to compressing plates and more particularly but not by way of limitation to a method and apparatus for the use of compressing plates to assist in osteosynthesis. 
         [0003]    2. Description of the Related Art 
         [0004]    Wire, staple, and plate fixation of bone have been used clinically for decades. In the last 20 years or so, nickel-titanium and shape memory materials have been used in orthopedics for their shape changing and superelastic properties. Shape memory devices feature a martensitic and austenitic form, in which the addition of energy in the form of heat transforms the device from a temporary mart site state to a final austenite state at a defined temperature. The heat for transformation generally is categorized as being (1) room temperature activated (i.e. superelastic), (2) body temperature activated (i.e. body temperature), and (3) above body temperature activated (i.e. heated). The use of a shape memory plate, capable of transforming from a preliminary shape to a compressed final shape, presents unique challenges. If the plate is superelastic, then the plate is inclined to immediately transform at room temperature, making implantation and the use of screws difficult for a surgeon. If the plate is body temperature or heated, then the surgeon has to rely on either body heat, which is reduced during surgery due to the open wound, or an external heating source to transform the plate. For various reasons, many surgeons would prefer a superelastic shape memory plate. 
         [0005]    Accordingly, an apparatus and a method of surgical use for a shape memory plate that restrains the plate in an open position while screws are attached and then releases the plate to compress the bones and assist with osteosynthesis would provide an improvement in compressing plate surgeries. 
       SUMMARY OF THE INVENTION 
       [0006]    In accordance with a fixation system of the present invention, a plate is movable between an implantation shape and an insertion shape such that the plate creates compression between a first bone and a second bone. The plate includes a body portion having a central axis. A first body section extends from the body portion and terminates in a first end portion, and a second body section extends from the body portion and terminates in a second end portion. The first body section and the second body section rotate about the central axis of the body portion during movement of the plate between the insertion shape and the implantation shape. The first end portion and the second end portion have a first linear distance when the plate is in the implantation shape and a second linear distance when the plate is in the insertion shape. The first linear distance is less than the second linear distance such that plate creates compression during movement of the plate from the insertion shape toward the implantation shape. First and second screw holes are disposed in the first body section, and third and fourth screw holes disposed in the second body section. 
         [0007]    An insertion tool holds the plate in the insertion shape and allows locating of the plate in the insertion shape for affixing with the first bone and the second bone. Release of the plate from the insertion tool after affixation of the plate with the first bone and the second bone allows the plate to move from its insertion shape to its implantation shape, thereby compressing the first bone with the second bone. The insertion tool includes a platform that mates with the body portion and the first and second body sections of the plate. The platform includes a first slot that aligns with the first and second screw holes of the plate and a second slot that aligns with the third and fourth screw holes of the plate. The insertion tool further includes a shaft secured with the platform. 
         [0008]    First and second drill guide tubes, each including an inner cannulation adapted to receive a locating pin or a drill bit, insert within the first slot of the platform and mate respectively with the first and second screw holes of the plate. Third and fourth drill guide tubes, each including an inner cannulation adapted to receive a locating pin or a drill bit, insert within the second slot of the platform and mate respectively with the third and fourth screw holes of the plate such that the platform holds the plate in the insertion shape. The first, second, third, and fourth screw holes of the plate include threads that engage a respective one of the first, second, third, and fourth drill guide tubes to maintain the first, second, third, and fourth drill guide tubes secured to the plate with the platform therebetween. After removal of the first, second, third, and fourth drill guide tubes, the threads engage a screw inserted into the first or second bones to maintain the plate secured with the first and second bones. 
         [0009]    First and second locating pins temporarily anchor the plate with the first and second bones. The first locating pin inserts through one of the first and second drill guide tubes and one of the first and second screw holes of the plate such that the first locating pin retains the plate at the first bone. The second locating pin inserts through one of the third and fourth drill guide tubes and one of the third and fourth screw holes of the plate such that the second locating pin retains the plate at the second bone. 
         [0010]    A drill bit is used to create a hole in the first and second bone. The drill bit inserts through one of the first, second, third, and fourth drill guide tubes and through one of the first and second screw hole of the plate to produce a drill hole in one of the first and second bones. 
         [0011]    A package may receive therein the plate coupled with the insertion tool such that the insertion tool retains the plate in its insertion position. The package maintains the plate and the insertion tool sterile after sterilization of the fixation system. The package may receive therein the plate coupled with the insertion tool such that the insertion tool retains the plate in its insertion position and the first, second, third, and fourth drill guide tubes coupled with the plate. The package maintains the plate, the insertion tool, and the first, second, third, and fourth drill guide tubes sterile after sterilization of the fixation system. 
         [0012]    In a method for affixing a first bone with a second bone, the fixation system of the present invention is placed onto the first and second bones. A first locating pin is inserted through the first drill guide tube and into the first bone and a second locating pin is inserted through the fourth drill guide tube and into the second bone to retain the fixation system on the first and second bones. A drill bit is inserted through the second drill guide tube to drill a hole into the first bone, and the drill bit is inserted through the third drill guide tube to drill a hole into the second bone. The second drill guide tube is removed from the plate, and a first screw is inserted through the insertion tool to secure the first screw with the plate and the first bone. The third drill guide tube is removed from the plate, and a second screw is inserted through the insertion tool to secure the second screw with the plate and the second bone. The first locating pin is removed from the first drill guide tube, and the second locating pin is removed from the fourth drill guide tube. The drill bit is inserted through the first drill guide tube to drill a hole into the first bone, and the drill bit is inserted through the fourth drill guide tube to drill a hole into the second bone. The first and fourth drill guide tubes are removed from the plate, and the insertion tool is decoupled from the plate. A third screw is secured with the plate and the first bone, and a fourth screw is secured with the plate and the second bone. The plate moves from the insertion shape to the implantation shape, thereby compressing the first bone and the second bone. 
         [0013]    In a method for affixing a first bone with a second bone, a first fixation system is placed onto the first and second bones. A first locating pin is inserted through the first drill guide tube of the first fixation system and into the first bone, and a second locating pin is inserted through the fourth drill guide tube of the first fixation system and into the second bone to retain the first fixation system on the first and second bones. A drill bit is inserted through the second drill guide tube of the first fixation system to drill a hole into the first bone. The drill bit is inserted through the third drill guide tube of the first fixation system to drill a hole into the second bone. The second drill guide tube of the first fixation system is removed from the plate of the first fixation system. A first screw is inserted through the insertion tool of the first fixation system and secured with the plate of the first fixation system and the first bone. The third drill guide tube of the first fixation system is removed from the plate of the first fixation system. A second screw is inserted through the insertion tool of the first fixation system and secured with the plate of the first fixation system and the second bone. The first locating pin is removed from the first drill guide tube of the first fixation system, and the second locating pin is removed from the fourth drill guide tube of the first fixation system. The drill bit is inserted through the first drill guide tube of the first fixation system to drill a hole into the first bone. The drill bit is inserted through the fourth drill guide tube of the first fixation system to drill a hole into the second bone. The first and fourth drill guide tubes of the first fixation system are removed from the plate of the first fixation system. A third screw is secured with the plate of the first fixation system and the first bone, and a fourth screw is secured with the plate of the first fixation system and the second bone. 
         [0014]    The second fixation system is placed onto the first and second bones. A first locating pin is inserted through the first drill guide tube of the second fixation system and into the first bone, and a second locating pill is inserted through the fourth drill guide tube of the second fixation system and into the second bone to retain the second fixation system on the first and second bones. A drill bit is inserted through the second drill guide tube of the second fixation system to drill a hole into the first bone. The drill bit is inserted through the third drill guide tube of the second fixation system to drill a hole into the second bone. The second drill guide tube of the second fixation system is removed from the plate of the second fixation system. A first screw is inserted through the insertion tool of the second fixation system and secured with the plate of the second fixation system and the first bone. The third drill guide tube of the second fixation system is removed from the plate of the second fixation system. A second screw is inserted through the insertion tool of the second fixation system and secured with the plate of the second fixation system and the second bone. The first locating pin is removed from the first drill guide tube of the second fixation system, and the second locating pin is removed from the fourth drill guide tube of the second fixation system. The drill bit is inserted through the first drill guide tube of the second fixation system to drill a hole into the first bone. The drill bit is inserted through the fourth drill guide tube of the second fixation system to drill a hole into the second bone. The first and fourth drill guide tubes of the second fixation system are removed from the plate of the second fixation system. A third screw is secured with the plate of the second fixation system and the first bone, and a fourth screw is secured with the plate of the second fixation system and the second bone. The insertion tool of the first fixation system is decoupled from the plate of the first fixation system, and the insertion tool of the second fixation system is decoupled from the plate of the second fixation system. The plates of the first and second fixation systems move from the insertion shape to the implantation shape, thereby compressing the first bone and the second bone. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a perspective view of a shape memory plate in a first shape according to a first embodiment. 
           [0016]      FIG. 2  is a front view of the shape memory plate in a first shape. 
           [0017]      FIG. 3  is a bottom view of the shape memory plate in a first shape. 
           [0018]      FIG. 4  is a top view of the shape memory plate in a first shape. 
           [0019]      FIG. 5  is a perspective view of the shape memory plate in a second shape. 
           [0020]      FIG. 6  is a front view of the shape memory plate in a second shape. 
           [0021]      FIG. 7  is a perspective view of a drill guide tube. 
           [0022]      FIG. 8  is a front view of the drill guide tube. 
           [0023]      FIG. 9  is a perspective view of a locating pin. 
           [0024]      FIG. 10  is a perspective view of a drill bit. 
           [0025]      FIG. 11  is a front view of a screw. 
           [0026]      FIG. 12  is a perspective view of an insertion tool. 
           [0027]      FIGS. 13 and 14  are side views of the insertion tool. 
           [0028]      FIG. 15  is a front view of the insertion tool and the shape memory plate in the first position 
           [0029]      FIG. 16  is a front view of the insertion tool and the shape memory plate in the second shape secured to the insertion tool using the drill guide tubes. 
           [0030]      FIG. 17  is a perspective view of the insertion tool and the shape memory plate in the second shape secured to the insertion tool using the drill guide tubes. 
           [0031]      FIG. 18  is a bottom view of the insertion tool and the shape memory plate in the second shape secured to the insertion tool using the drill guide tubes. 
           [0032]      FIGS. 19-24  are perspective views illustrating the use of the insertion tool in affixing the shape memory plate to a first bone and a second bone. 
           [0033]      FIGS. 25-26  are perspective views illustrating the affixing of the shape memory plate to the first and second bones once the insertion tool is removed from the shape memory plate. 
           [0034]      FIG. 27  is a perspective view of a shape memory plate in a first shape according to a second embodiment. 
           [0035]      FIG. 28  is a front view of the shape memory plate in a first shape. 
           [0036]      FIG. 29  is a bottom view of the shape memory plate in a first shape. 
           [0037]      FIG. 30  is a top view of the shape memory plate in a first shape. 
           [0038]      FIG. 31  is a perspective view of the shape memory plate in a second shape. 
           [0039]      FIG. 32  is a front view of the shape memory plate in a second shape. 
           [0040]      FIG. 33  is a perspective view of a drill guide tube. 
           [0041]      FIG. 34  is a front view of the drill guide tube. 
           [0042]      FIG. 35  is a perspective view of a locating pin. 
           [0043]      FIG. 36  is a perspective view of a drill bit. 
           [0044]      FIG. 37  is a front view of a screw. 
           [0045]      FIG. 38  is a perspective view of an insertion tool. 
           [0046]      FIGS. 39 and 40  are side views of the insertion tool. 
           [0047]      FIG. 41  is a front view of the insertion tool and the shape memory plate in the first position. 
           [0048]      FIG. 42  is a front f the insertion tool and the shape memory plate in the second shape secured to the insertion tool using the drill guide tubes. 
           [0049]      FIG. 43  is a perspective view of the insertion tool and the shape memory plate in the second shape secured to the insertion tool using the drill guide tubes. 
           [0050]      FIG. 44  is a bottom view of the insertion tool and the shape memory plate in the second shape secured to the insertion tool using the drill guide tubes. 
           [0051]      FIGS. 45-50  are perspective views illustrating the use of the insertion tool in affixing the shape memory plate to a first bone and a second bone. 
           [0052]      FIGS. 51-52  are perspective views illustrating the affixing of the shape memory plate to the first and second bones once the insertion tool is removed from the shape memory plate. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0053]    As required, a detailed embodiment of the present invention is disclosed herein; however, it is to be understood that the disclosed embodiment is merely exemplary of the invention, which may be embodied in various forms. It is further to be understood that the figures are not necessarily to scale, and some features may be exaggerated to show details of particular components or steps. 
         [0054]      FIGS. 1-6  illustrate an orthopedic plate  100  according to a first embodiment. The plate  100  can be fabricated from a shape memory material such as nitinol (nickel-titanium), or any other elastic material capable of deforming and rebounding to an original shape. The plate  100  includes a body portion  160 , screw holes  111 - 114 , a central axis  161 , a first body section  171  terminating in an end portion  116 , and a second body section  1172  terminating in an end portion  117 . One of ordinary skill in the art will recognize that the plate  100  may include more or less screw holes depending upon the type of surgery. The screw holes  111 - 114 , or any number of screw holes, can be smooth, tapered, or threaded as necessary to engage a screw. In the first embodiment, the screw holes  111 - 114  are shown with threads. The plate  100  moves between a first implanted shape  1000  illustrated in  FIGS. 1-4  and a second insertion shape  1001  illustrated in  FIGS. 5 and 6 . The first implanted shape  1000  is the original fabrication shape of the plate  100 . In moving between the first implanted shape  1000  and the second insertion shape  1001 , the end portions  116  and  117  move between a first position  1100  and a second position  1101 . 
         [0055]    In the first embodiment, the plate  100  operates to create compression between first and second bones or bone parts. In the first implanted shape  1000 , the end portions  116  and  117  in their first positions  1100  have a first linear distance therebetween. In the second insertion shape  1001 , the end portions  116  and  117  in their second position  1101  have a second linear distance therebetween. The second linear distance of the second insertion shape  1001  is greater than the first linear distance of the first implanted shape  1000 . 
         [0056]    In moving from the second insertion shape  1001  to the first implanted shape  1000 , the first body section  171  and the second body section  171  pivot about the central axis  161  such that the end portions  116  and  117  move from their second position  1101  to their first position  1100 . As a result, the end portions  116  and  117  move from their second linear distance to their first linear distance thereby creating compression between first and second bones or bone parts. One of ordinary skill in the art will recognize that the linear distance traveled by the end portions  116  and  117  from the second position  1101  to the first position  1100  can be any amount that creates a desired level of compression. 
         [0057]    The plate  100  begins in the first implanted shape  1000  and through application of an external force, the plate is moved from its first implanted shape  1000  to its second insertion shape  1001 . In particular, the application of an external force causes the first body section  171  and the second body section  171  to pivot about the central axis  161  such that the end portions  116  and  117  move from their first position  1100  to their second position  1101 . 
         [0058]    The plate  100  may change shape from the second shape  1001  to the first implanted shape  1000  through the application of energy delivered from an external source such as room temperature, body temperature, or an external energy device. In the first embodiment however, the plate  100  is superelastic in that the plate  100  internally stores mechanical energy in its metallic structure when moved from its original first implanted shape  1000  to its second insertion shape  1100 . The mechanical energy remains stored within the plate  100  as the plate  100  is held in the second shape  1001 . Upon release the mechanical energy is recovered when the plate  100  moves from the second shape  1001  to the first implanted shape  1000 . In moving from the from the second shape  1000  to the first implanted shape  1000 , the end portions  116  and  117  move from the second position  1101  to the first position  1100 . In particular, in moving from the second position  1101  to the first position  1100 , the end portions  116  and  117  move from their second linear distance to their first linear distance, thus reducing the distance between the end portions  116  and  117 . Furthermore, in moving between the second shape  1001  and the first implanted shape  1000 , the screw holes  111 - 114  can remain circular or change shape if it is desired that they bind upon screws. 
         [0059]      FIGS. 7 and 8  illustrate a drill guide tube  200 . The drill guide tube  200  can be made from metal or plate, and has an inner cannulation of diameter  210  and an outer surface  220 . A shoulder  230  is a location where a large outer surface  220  reduces to a new small outer surface  240  of smaller diameter. The screw threads  250  extend from the small outer surface  240 , and are of the same thread characteristics needed to mate with the screw holes  111 - 114  of the plate  100 . 
         [0060]      FIG. 9  illustrates a locating pin  300 . The locating pin  300  can be manufactured of any material; in the first embodiment, it is made from medical grade metal. A shank  320  of the locating pin  300  is of a diameter that will fit into the inner cannulation  210  of the drill guide tube  200 . The locating pin  300  holds the plate  100  in a desired position so that a surgeon can drill holes into the patient&#39;s bone. 
         [0061]      FIG. 10  illustrates a drill bit  350 . The drill bit  350  has cutting flutes  360  for cutting through bone and can be manufactured of any material; in the first embodiment, it is made from medical grade metal. The drill bit  350  is of a diameter that will fit into the inner cannulation  210  of the drill guide tube  200 . The drill bit  350  may include sizing lines to define certain depths for the drilling of a pilot hole. 
         [0062]      FIG. 11  illustrates a screw  400  designed to attach the plate  100  to a bone. In the first embodiment, the screw  400  has two threaded sections, shank threads  410  and head threads  420 . The shank threads  410  are designed to engage bone once inserted into a pilot hole created by the drill bit  350 . There is any number of thread characteristics related to pitch, diameter, and threads per inch that will accomplish this purpose. The head threads  420  are designed to engage the screw holes  111 - 114  of the plate  100 . 
         [0063]      FIGS. 12-14  illustrate an insertion tool  500 . The insertion tool  500  consists of platform  530  that includes drill guide slots  541  and  542 . The platform  530  is a solid material such as metal or plastic, designed to space the drill guide slots  541  and  542  to the proper separation distance, as well as retain the plate  100  in the second shape  1001 . Accordingly, the drill guide slot  541  aligns with the first body section  171  and screws holes  111  and  112  and the drill guide slot  542  aligns with the second body section  172  and the screw holes  113  and  114 . 
         [0064]      FIGS. 15-18  illustrate an assembly showing the plate  100 , the four drill guide tubes  200 , and the insertion tool  500 . The plate  100  begins in the first implanted shape  1000  and ends in the second shape  1001  upon assembly with the insertion tool  500 . The body portion  160  of the plate  100  mates with the platform  530  of the insertion tool  500 . After mating with the platform  530 , the drill guide tubes  200  are used secure the plate  100  to the platform  530  of the insertion tool  500 . In particular, the small outer surface  240  of the drill guide tubes  200  pass through the drill guide slots  541  and  542  that are located on the platform  530  of the insertion tool  500 . The screw threads  250  on the drill guide tubes  200  are screwed into the screw holes  111 - 114  of the plate  100  until the shoulders  230  of the drill guide tubes  200  abut the platform  530  of the insertion tool  500 . In the first embodiment, the drill guide tubes  200  screw into the screw holes  112  and  113  and then into the screw holes  111  and  114  thereby securing the plate  100  to the platform  530  of the insertion tool  500 . Once secured to the platform  530  of the insertion tool  500 , the drill guide tubes  200  maintain the plate  100  in its second shape  1001 . In mating the plate  100  with the platform  530 , it may be necessary to first mechanically deform the plate  100  from the first shape implanted  1000  to the second shape  1001  before securing the plate  100  with the platform  530 . Alternatively, securing the plate  100  with the platform  530  using the drill guide tubes  200  may facilitate the mechanical deformation of the plate  100  from the first implanted shape  1000  to the second shape  1001  without prior mechanical deformation. 
         [0065]      FIGS. 19-26  illustrate a method of use for a shape memory plate  100  to fixate two bones or bone fragments in a surgery. The surgical procedure begins with the surgeon trying to fixate a first bone  710  and a second bone  720 . As illustrated in  FIG. 19 , the plate  100  resides in the second shape  1001  as a result of the securing of the plate  100  to the insertion tool  500  using the drill guide tubes  200  as described above. Using the insertion tool  500 , the plate  100  is positioned on top of a bone fusion interface  730 , which lies between the first bone  710  and the second bone  720 . The screw holes  111 - 114  of the plate  100  are positioned so that the screw holes  111  and  112  are over the first bone  710  and screw holes  113  and  114  are over the second bone  720 . 
         [0066]    After positioning the plate  100 , the surgeon uses two locating pins  300  to temporarily anchor the plate  100  in place. Specifically, the surgeon places the locating pins  300  through the drill guide tubes  200 , through the platform  530  of the insertion tool  500 , through respective screw holes  111  and  114  of the plate  100 , and then into respective first and second bones  710  and  720 . Once the plate  100  is anchored in place, the surgeon drills pilot holes into the first and second bones  710  and  720  using the drill bit  350 . Specifically, the surgeon drills pilot holes through the drill guide tubes  200 , through the platform  530  of the insertion tool  500 , through respective screw holes  112  and  113  of the plate  100 , and then into respective first and second bones  710  and  720 . The surgeon can use any sizing lines located on the drill bit  350  to assess the depth of a screw  400  to anchor the plate  100 . 
         [0067]    At this time, the surgeon is ready to screw the plate  100  to the first and second bones  710  and  720 . As illustrated in  FIG. 20 , the drill guide tubes  200  corresponding to the screw holes  112  and  113  have been removed from the plate  100  and the platform  530  of the insertion tool  500 . Referring to  FIG. 21 , the surgeon then inserts first and second screws  400  into the screw holes  112  and  113  of the plate  100  To reach the screw holes  112  and  113 , the first and second screws  400  pass through the screw slots  541  and  542  of the insertion tool  500 . The head threads  420  of the screws  400  mate with the screw hole  112  and  113  of the plate  100  and the shank threads  410  of the screws  400  are screwed into the first bone  710  and the second bone  720 . 
         [0068]    As illustrated in  FIG. 22 , once the first and second screws  400  have been screwed into the first bone  710  and the second bone  720 , the two locating pins  300  are removed from the drill guide tubes  200 , the platform  530  of the insertion tool  500 , and the plate  100 . The surgeon drills pilot holes through the drill guide tubes  200 , through the platform  530  of the insertion tool  500 , through respective screw holes  111  and  114  of the plate  100 , and then into respective first and second bones  710  and  720  as shown in  FIG. 23 . Referring to  FIG. 24 , the remaining drill tubes  200  corresponding to screw holes  111  and  114  are removed from the plate  100  and the platform  530  of the insertion tool  500 . The insertion tool  500  is then removed from the plate  100  as illustrated in  FIG. 25 . 
         [0069]      FIG. 26  illustrates the final step in the implantation of the plate  100  in the first bone  710  and the second bone  720 . Third and fourth screws  400  respectively are screwed into the screw holes ill and  114  of the plate  100 . The head threads  420  of the third and fourth screw  400  mate with the screw holes  111  and  114  of the plate  100  and the shank threads  410  of the screws  400  are screwed into the first bone  710  and the second bone  720 . With the insertion tool  500  removed and the first, second, third, and fourth screws  400  secured with the plate  100  and the first and second bones  710  and  720 , the shape memory plate  100  transforms from the second shape  1001  to the first implanted shape  1000 . In particular, the end portions  116  and  117  move toward each other from the second position  1101  to the first position  1100  creating an arc in the body portion  160 . Upon the transitioning of the plate  100  to the first implanted shape  1000 , compression is created between the first bone  710  and the second bone  720  at the bone fusion location  730 . 
         [0070]    Summarizing the implantation, the surgeon selects a shape memory plate implant pre-loaded onto an insertion tool. The surgeon positions the plate at the juncture of two bones to be fused or fixated, and uses locating pins to temporarily hold the plate to the bones. The surgeon drills pilot holes into the bone. The surgeon then removes a first and second drill guide tube, replaces them with screws to keep the plate in place. The locating pins are removed and third and fourth pilot holes are drilled through the remaining drill guide tubes and into the bone. The surgeon removes the remaining drill guide tubes and replaces them with screws to secure the plate to the bone. 
         [0071]    The ingenuity of this system is as follows. A shape memory plate that creates compression has to be held in a second insertion position until both sides of the plate are anchored in bone, lest the compressive force be released too early. This can be accomplished initially with an insertion tool that holds the plate in the second insertion position. However, the plate has to be anchored to the bone before the insertion tool can be removed to preserve the compressive force until the surgeon is ready. This then requires that the screws pass through the insertion tool in some way. The aforementioned method for implantation accomplishes these objectives. Furthermore, this method allows the surgeon to select the timing of the application of compressive force. A surgeon could potentially implant more than one plate, and leave the insertion tools in place, only to release them at the appropriate time. This sequence could allow more complex surgeries to take place. Furthermore, since the presence of the insertion tool can hide or obscure the visibility of the plate from the surgeon, the two locating pins insure that the plate remains properly oriented on the bones. 
         [0072]    To use the plate  100 , a medical device company or hospital could pre-load certain elements of the system prior to surgery. The plate  100  is moved from its first implanted shape  1000  shown in  FIG. 1  to its second shape  1001  shown in  FIG. 5 . The plate  100  is held in its second shape  1001  via the drill guides tubes  200  and the insertion tool  500 , which restrains the plate  100  in its second shape  1001 . The plate  100  could be pre-loaded and delivered in a sterile package or, alternatively, the plate  100  shipped and prepared as described above before surgery. 
         [0073]      FIGS. 27-32  illustrate an orthopedic plate  2000 . The plate  2000  can be fabricated from a shape memory material such as nitinol (nickel-titanium), or any other elastic material capable of deforming and rebounding to an original shape. The plate  2000  includes a body portion  2160 , screw holes  2111 - 2114 , a central axis  2161 , a first body section  2171  terminating in an end portion  2116 , and a second body section  2172  terminating in an end portion  2117 . One of ordinary skill in the art will recognize that the plate  2000  may include more or less screw holes depending upon the type of surgery. The screw holes  2111 - 2114 , or a number of screw holes, can be smooth, tapered, or threaded as necessary to engage a screw. In the second embodiment, the screw holes  2111 - 2114  are shown with threads. The plate  2000  moves between a first implanted shape  2001  illustrated in  FIGS. 1-4  and a second insertion shape  2002  illustrated in  FIGS. 5 and 6 . The first shape  2001  is the original fabrication shape of the plate  2000 . In moving between the first implanted shape  2001  and the second insertion shape  2002 , the end portions  2116  and  2117  move between a first position  2100  and a second position  2101 . 
         [0074]    In the second embodiment, the plate  2000  operates to create compression between first and second bones or bone parts. As such, the plate  2000  in the first shape  2001  has an arc in the body portion  2160  such that the end portions  2116  and  2117  in their first positions  2100  create compression between first and second bones or bone parts. In the second embodiment, the body portion  2160  of the plate  2000  in the second shape  2001  is substantially fiat. However, the second shape  2002  of the plate  2000  may include an arc in the body portion  2160 . In moving from the second shape  2002  to the first shape  2001 , the end portions  2116  and  2117  move from the second position  2101  to the first position  2100  creating a more pronounced arc in the body portion  2160  between the second shape  2002  and the first shape  2001 . One of ordinary skill the art will recognize that the amount of arc created in the body portion  2160  can be any amount that creates the desired compression. 
         [0075]    The plate  2000  begins in the first shape  2001  and through application of an external force, the plate  2000  is moved from its first implantation shape  2001  to its second insertion shape  2002 . In particular, the application of an external force causes the end portions  2116  and  2117  to bend away from each other, moving from the first position  2100  to the second position  2101  thereby substantially removing the arc from the body portion  2160  of the plate  2000 . 
         [0076]    The plate  2000  may change shape from the second shape  2002  to the first shape  2001  through the application of energy delivered from an external source such as room temperature, body temperature, or an external energy device. In the second embodiment however, the plate  2000  is superelastic in that the plate  2000  internally stores mechanical energy in its metallic structure when moved from its original first implantation shape  2001  to its second insertion shape  2002 . The mechanical energy remains stored within the plate  2000  as the plate  2000  is held in the second shape  2002 . Upon release the mechanical energy is recovered when the plate  2000  moves from the second shape  2002  to the first shape  2001 . In moving from the from the second shape  2002  to the first shape  2001 , the end portions  2116  and  2117  move from the second position  2101  to the first position  2100 . In particular, in moving from the second position  2101  to the first position  2100 , the end portions  2116  and  2117  contract reducing the distance between the end portions  2116  and  2117  and creating an arc in the body portion  2160  and the first and second body sections  21   71  and  2172 . Furthermore,in moving between the second shape  2002  and the first shape  2001 , the screw holes  2111 - 2114  can remain circular or change shape if it is desired that they bind upon screws. 
         [0077]      FIGS. 33 and 34  illustrate a drill guide tube  2005 . The drill guide tube  2005  can be made from metal or plate, and has an inner cannulation of diameter  2210  and an outer surface  2220 . A shoulder  2230  is a location where a large outer surface  2220  reduces to a new small outer surface  2240  of smaller diameter. The screw threads  2250  extend from the small outer surface  2240 , and are of the same thread characteristics needed to mate with the screw holes  2111 - 2114  of the plate  2000 . 
         [0078]      FIG. 35  illustrates a locating pin  2300 . The locating pin  2300  can be manufactured of any material; in the second embodiment, it is made from medical grade metal. A shank  2320  of the locating pin  2300  is of a diameter that will fit into the inner cannulation  2210  of the drill guide tube  2005 . The locating pin  2300  holds the plate  2000  in a desired position so that a surgeon can drill holes into the patient&#39;s bone. 
         [0079]      FIG. 36  illustrates a drill bit  2350 . The drill bit  2350  has cutting flutes  2360  for cutting through bone and can be manufactured of any material; in the second embodiment, it is made from medical grade metal. The drill bit  2350  is of a diameter that will fit into the inner cannulation  2210  of the drill guide tube  2005 . The drill bit  2350  may include sizing lines to define certain depths for the drilling of a pilot hole. 
         [0080]      FIG. 37  illustrates a screw  2400  designed to attach the plate  2000  to a bone. In the second embodiment, the screw  2400  has two threaded sections, shank threads  2410  and head threads  2420 . The shank threads  2410  are designed to engage bone once inserted into a pilot hole created by the drill bit  2350 . There is any number of thread characteristics related to pitch, diameter, and threads per inch that will accomplish this purpose. The head threads  2420  are designed to engage the screw holes  2111 - 2114  of the plate  2000 . 
         [0081]      FIGS. 38-40  illustrate an insertion tool  2500 . The insertion tool  2500  consists of a handle  2510 , a shaft  2520 , and a platform  2530 . The handle  2510  can be any shape such that it ergonomically fits a surgeon&#39;s hand. The shaft  2520  can be any length or angle as required to position the platform  2530  on a desired bone surface. In some applications, the shaft  2520  might not be needed at all, and could thus be eliminated from the insertion tool  2500 . The platform  2530  is a solid material such as metal or plastic, designed to space drill guide holes  2541 - 2544  to the proper separation distance, as well as retain the plate  2000  in the second shape  2002 . Thus, the drill guide holes  2541 - 2544  of the platform  2530  correspond to the separation distance of the screw holes  2111 - 2114  of the plate  2000  when it is in the second shape  2002 . Although the second embodiment of the platform  2530  includes the drill guide holes  2541 - 2544 , one of ordinary skill in the art will recognize that the screw holes  2541 - 2542  and the screw holes  2541 - 2542  respectively could be replaced with slots similar to the drill guide slot  541  and the drill guide slot  542  of the platform  530  according to the first embodiment. 
         [0082]      FIGS. 41-44  illustrate an assembly showing the plate  2000 , the four drill guide tubes  2005 , and the insertion tool  2500 . The plate  2000  begins in the first shape  2001  and ends in the second shape  2002  upon assembly with the insertion tool  2500 . The body portion  2160  and the first and second body sections  2171  and  2172  of the plate  2000  mate with the platform  2530  of the insertion tool  2500 . After mating with the platform  2530 , the drill guide tubes  2005  are used secure the plate  2000  to the platform  2530  of the insertion tool  2500 . In particular, the small outer surface  2240  of the drill guide tubes  2005  pass through the drill guide holes  2541 - 2544  that are located on the platform  2530  of the insertion tool  2500 . The screw threads  2250  on the drill guide tubes  2200  are screwed into the screw holes  2111 - 2114  of the plate  2000  until the shoulders  2230  of the drill guide tubes  2005  abut the platform  2530  of the insertion tool  2500 . In the second embodiment, the drill guide tubes  2005  screw into the screw holes  2112  and  2113  and then into the screw holes  2111  and  2114  thereby securing the plate  2000  to the platform  2530  of the insertion tool  2500 . Once secured to the platform  2530  of the insertion tool  2500 , the drill guide tubes  2005  maintain the plate  2000  in its second shape  2002 . In mating the plate  2000  with the platform  2530 , it may be necessary to first mechanically deform the plate  2000  from the first shape  2001  to the second shape  2002  before securing the plate  2000  with the platform  2530 . Alternatively, securing the plate  2000  with the platform.  2530  using the drill guide tubes  2005  may facilitate the mechanical deformation of the plate  2005  from the first shape  2001  to the second shape  2002  without prior mechanical deformation. 
         [0083]      FIGS. 45-52  illustrate a method of use for a shape memory plate  2000  to fixate two bones or bone fragments in a surgery. The surgical procedure begins with the surgeon trying to fixate a first bone  2710  and a second bone  2720 . As illustrated in  FIG. 45 , the plate  2000  resides in the second shape  2002  as a result of the securing of the plate  2000  to the insertion tool  2500  using the drill guide tubes  2005  as described above. Using the insertion tool  2500 , the plate  2000  is positioned on top of a bone fusion interface  2730 , which lies between the first bone  2710  and the second bone  2720 . The screw holes  2111 - 114  of the plate  2000  are positioned so that the screw holes  2111  and  2112  are over the first bone  2710  and screw hole  2113  and  2114  are over the second bone  2720 . 
         [0084]    After positioning the plate  2000 , the surgeon uses two locating pins  2300  to temporarily anchor the plate  2000  in place. Specifically, the surgeon places the locating pins  2300  through the drill guide tubes  2005 , through the platform  2530  of the insertion tool  2500 , through respective screw holes  2111  and  2 . 11 . 4  of the plate  2000 , and then into respective first and second bones  2710  and  2720 . Once the plate  2000  is anchored in place, the surgeon drills pilot holes into the first and second bones  2710  and  2720  using the drill bit  2350 . Specifically, the surgeon drills pilot holes through the drill guide tubes  2005 , through the platform  2530  of the insertion tool  2500 , through respective screw holes  2112  and  2113  of the plate  2000 , and then into respective first and second bones  2710  and  2720 . The surgeon can use any sizing lines located on the drill bit  2350  to assess the depth of a screw  2400  to anchor the plate  2000 . 
         [0085]    At this time, the surgeon is ready to screw the plate  2000  to the first and second bones  2710  and  2720 . As illustrated in  FIG. 46 , the drill guide tubes  2005  corresponding to the screw holes  2112  and  2113  have been removed from the plate  2000  and the platform  2530  of the insertion tool  2500 . Referring to  FIG. 47 , the surgeon then inserts first and second screws  2400  into the screw holes  2112  and  2113  of the plate  2000 . To reach the screw holes  2112  and  2113 , the first and second screws  2400  pass through the screw holes  2542  and  2543  of the insertion tool  2500 . The head threads  2420  of the screws  2400  mate with the screw hole  2112  and  2113  of the plate  2000  and the shank threads  2410  of the screws  2400  are screwed into the first bone  2710  and the second bone  2720 . 
         [0086]    As illustrated in  FIG. 48 , once the first and second screws  2400  have been screwed into the first bone  2710  and the second bone  2720 , the two locating pins  2300  are removed from the drill guide tubes  2005 , the platform  2530  of the insertion tool  2500 , and the plate  2000 . The surgeon drills pilot holes through the drill guide tubes  2005 , through the platform  2530  of the insertion tool  2500 , through respective screw holes  2111  and  2114  of the plate  2000 , and then into respective first and second bones  2710  and  2720  as shown in  FIG. 49 . Referring to  FIG. 50 , the remaining drill tubes  2005  corresponding to screw holes  2111  and  2114  are removed from the plate  2000  and the platform  2530  of the insertion tool  2500 . The insertion tool  2500  is then removed from the plate  2000  as illustrated in  FIG. 51 . 
         [0087]      FIG. 52  illustrates the final step in the implantation of the plate  2000  in the first bone  2710  and the second bone  2720 . Third and fourth screws  2400  respectively are screwed into the screw holes  2111  and  2114  of the plate  2000 . To reach the screw holes  2111  and  2114 , the third and fourth screws  2400  pass through the screw holes  2541  and  2544  of the insertion tool  2500 . The head threads  2420  of the third and fourth screw  2400  mate with the screw holes  2111  and  2114  of the plate  2000  and the shank threads  2410  of the screws  2400  are screwed into the first bone  2710  and the second bone  2720 . With the insertion tool  2500  removed and the first, second, third, and fourth screws  2400  secured with the plate  2000  and the first and second bones  2710  and  2720 , the shape memory plate  2000  transforms from the second shape  2002  to the first shape  2001 . In particular, the end portions  2116  and  2117  move toward each other from the second position  2101  to the first position  2100  creating an arc in the body portion  2160 . Upon the transitioning of the plate  2100  to the first shape  2001 , compression is created between the first bone  2710  and the second bone  2720  at the bone fusion location  2730 . 
         [0088]    Summarizing the implantation, the surgeon selects a shape memory plate implant pre-loaded onto an insertion tool. The surgeon positions the plate at the juncture of two bones to be fused or fixated, and uses locating pins to temporarily hold the plate to the bones. The surgeon drills pilot holes into the bone. The surgeon then removes a first and second drill guide tube, replaces them with screws to keep the plate place. The locating pins are removed and third and fourth pilot holes are drilled through the remaining drill guide tubes and into the bone. The surgeon removes the remaining drill guide tubes and replaces them with screws to secure the plate to the bone. 
         [0089]    The ingenuity of this system is as follows. A shape memory plate that creates compression has to be held in a second insertion position until both sides of the plate are anchored in bone, lest the compressive force be released too early. This can be accomplished initially with an insertion tool that holds the plate in the second insertion position. However, the plate has to be anchored to the bone before the insertion tool can be removed to preserve the compressive force until the surgeon is ready. This then requires that the screws pass through the insertion tool in some way. The aforementioned method for implantation accomplishes these objectives. Furthermore, this method allows the surgeon to select the timing of the application of compressive force. A surgeon could potentially implant more than one plate, and leave the insertion tools in place, only to release them at the appropriate time. This sequence could allow more complex surgeries to take place. Furthermore, since the presence of the insertion tool can hide or obscure the visibility of the plate from the surgeon, the two locating pins insure that the plate remains properly oriented on the bones. 
         [0090]    To use the plate  2000 , a medical device company or hospital could pre-load certain elements of the system prior to surgery. The plate  2000  is moved from its first implantation shape  2001  shown in  FIG. 27  to its second insertion shape  2002  shown in  FIG. 31 . The plate  2000  is held in its second shape  2002  via the drill guides tubes  2005  and the insertion tool  2500 , which restrains the plate  2000  in its second shape  2002 . The plate  2000  could be pre-loaded and delivered in a sterile package or, alternatively, the plate  2000  shipped and prepared as described above before surgery. 
         [0091]    Although the present invention has been described in terms of the foregoing preferred embodiments, such description has been fir exemplary purposes only and, as will be apparent to those of ordinary skill in the art, many alternatives, equivalents, and variations of varying degrees will fall within the scope of the present invention. That scope, accordingly, is not to be limited in any respect by the foregoing detailed description; rather,it is defined only by the claims that follow.

Technology Classification (CPC): 0