Abstract:
An apparatus and method of reducing and fixating bone fragments during osteosynthesis is disclosed. An internal fixation plate has first and second arms forming an acute angle. Attachment locations adapted to secure the plate to bone are located at distal portions of the respective arms. A third attachment location is located intermediate the first and second attachment locations. The arms have both a rigid retainer portion to assist in aligning opposing bone fragments and a flexible portion that desirably conforms to the surface of the bone to which it is to be fastened without requiring a surgeon to attempt to bend the plate prior to fastening it to the bone. A method is described for using the plate in combination with a tension-wire method that uses monocortical screws with stainless-steel wire to reduce and fixate a fracture.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Application claims the benefit of U.S. Provisional Application 60/350,785 filed Nov. 9, 2001 entitled V-Plate-Wire Mandible Fixation System. 

   BACKGROUND 
   Mandible fractures are common facial injuries, which can occur following severe impacts such as those experienced in motor vehicle accidents and sports. Repair of mandibular fractures first requires bringing the fragments into their correct anatomical position (reduction) and appropriate alignment of the fracture segments so that they can be immobilized (fixated) during fracture healing. When these two goals can be accomplished efficiently and with minimal tissue disruption, the risk of malunion and infection are reduced. 
   The mandible has an outer surface that is called the outer cortex. Even though this cortical surface is fractured, the bone fragments may not move relative to each other. In general, if the fragments do not move, they are considered stable (or favorable) and are usually managed with conservative techniques, including wiring the upper jaw and the mandible together (intermaxillary fixation or “IMF”) to maintain their pre-existing or normal dental occlusion (the way upper and lower teeth meet). When one of the fragments moves towards the cheek or lips (buccal-labial movement), or towards the tongue (lingual movement), it is unstable (or unfavorable) and surgical methods of open reduction/internal fixation (ORIF) must be considered. Treatment of mandibular fractures using an ORIF technique generally proceeds by first performing IMF and then reducing the fractured bone, and then securing (fixating) the bone in place. 
   Depending upon the anatomic location and the specific characteristics of the fracture site  100 , best seen in  FIG. 1 , fixation is accomplished through a variety of techniques including drilling holes through the bone and wiring them together (interosseous wiring) (not shown) or by using plates. An internal fixation plate  98  is generally a flat, elongated section of rigid metal containing screw holes at various points along its length for receiving screws to fasten the plate to the bone. One or more plates are placed across a fracture line  100  to fix the bone mass on both sides of the fracture to each other. The plates are secured to the bone with fasteners, usually screws. Interosseous wiring is simple, inexpensive, and needs less exposure of the tissue than that required for plate fixation techniques. It can also reduce and fixate the fracture, but this repair is non-rigid and tends to loosen because of the pressure the thin wire threaded through the bone exerts on the comparatively soft cortical bone. Because the forces the patient exerts when chewing (mastication) exceed the elastic limits of the interosseous wires, this technique not only requires the contemporaneous use of IMF during surgery (as is also done with plating) but also for as long as 6 weeks after surgery. Plate systems, however, can often be used without IMF after surgery. 
   To facilitate bone fracture healing (osteosynthesis), these fixation systems typically employ metallic hardware, including plate and screws, formed of biocompatible, corrosion resistant metals such as titanium and stainless steel. Systems utilizing resorbable materials have also recently been introduced. 
   While the main advantage of metallic plates is that they are strong and provide rigid stabilization of the fragments during osteosynthesis, they possess a number of inherent shortcomings. First, in order to accomplish reduction of the fragments, the surgeon must bring the bone fragments into proper alignment. This procedure usually requires the use of a surgical assistant who brings the fragments into alignment and then holds them in position either manually, or with a special tool. Second, because the surface of the mandible is not completely flat, the surgeon typically uses instruments to twist, bend and attempt to conform the conventional flat metal plate to the portion of the mandible onto which it is to be affixed. Shaping and re-shaping the rigid metal plates to conform adequately to bone surfaces is largely accomplished through trial and error. This method, usually conducted while the patient is under anesthesia, increases the requirements for anesthesia and operating room time. If the plate is not shaped correctly to conform to the bone surface, the rigid plate creates an additional problem because during osteosynthesis, bony fragments conform to the plate forcing the bone to heal in an anatomically incorrect position, which may result in dental malocclusion (errors in the way the upper and lower teeth meet to chew food). 
   Some conventional internal fixation plates have a compression feature that uses the force exerted by tightening the screw in the eccentrically shaped hole through the plate to force the fragments together. When this plate is used, a drill bit is used to drill a hole at the outer edge of the (eccentric compression) hole. A screw is then inserted into the hole and tightened enough to hold the plate in approximate position over the fracture site. The surgeon then turns his attention to the opposite fragment and repeats the procedure by drilling another hole to the outside of the opposite (eccentric compression) hole. The two screws are tightened to obtain compression of the fragments. Two additional screws are then placed through the holes in the outer portion of the plate and the system is stabilized. This technique is not very forgiving. Over or under compression of the fragments can cause displacement. If the mandible is inaccurately positioned, malunion or malocclusion may result. To prevent this undesirable, result, the plate may have to be reapplied in a new position. 
   Conventional rigid internal fixation plating techniques can also increase the opportunity for complications. For example, the exposure necessary for insertion of large plates can devascularize cortical (outer layer of) bony fragments. Plating on both sides of the mandible (bicortical), also risks injury to the inferior alveolar neurovascular bundle. While rigid plates may effectively restrain the opposing bone fragments against relative movement, as is required to achieve osteosynthesis, when they are not properly positioned, that same rigidity may contribute to bony deformation and malunion. 
   Rigid fixation of unstable, distracted mandibular fractures is often associated with a “catch-22” problem that requires accurate reduction to fixate while simultaneously needing some method of temporarily fixating the fragments in reduction in order to apply the chosen rigid fixation. 
   A tension-wire method that uses monocortical screws with stainless-steel wire for fracture reduction and fixation in conjunction with intermaxillary fixation has been described in Wang et al., Arch. Otolaryngol. Head Neck Surg. 124 (April 1998)448-452. In Wang, two screw holes for 2.0-mm-diameters self-tapping titanium or stainless-steel screws, 4 or 6 mm in length, are placed perpendicular to and on each side of the fracture line. Monocortical screws are placed approximately 4 to 6 mm from the fracture line. The screws are then tightened down and then reversed 2 turns to allow a 24-gauge stainless-steel wire loop to be passed around them and fit underneath the head of the first screw. The wire loop, which is tightened around the two screws, both reduces and fixates the opposing sides of the fractured bone. Because the head of the screws are conical, tightening the screws results in further reduction of the fragments. 
   While the above described tension-wire method (TWM) was originally devised as a method of temporary reduction for rigid fixation, it has been found to be a stable and effective method of fixation. When compared to methods utilizing miniplates, or dynamic compression plates, the TWM also requires less dissection and exposure of the tissues than that required for plating or lag screw techniques, and it is applicable to most simple fractures of the parasymphysis, body, angle, and ramus without the need for external incisions. TWM reduces and fixates the fracture simultaneously and can also be used to reduce an unstable fracture. The TWM is quite strong when two or more planes of fixation can be achieved. Other screw and wire loops can be added to adjust reduction. Despite its advantages, one disadvantage of the TWM alone, which is not encountered with plate and lag screw rigid fixation devices, is the concurrent need for use of IMF, which precludes immediate oral rehabilitation. Because IMF generally supplements the TWM, it should not be used where IMF is contraindicated, such as elderly, debilitated patients and those with increased nutritional demands for whom early oral rehabilitation is important. 
   Finite element analysis of TWM demonstrates that because the wire is usually plastically deformed while being tightened, it suffers from lack of strength to support biting forces (mastication) during the period of fracture healing. Since IMF must generally supplement TWM, the patient&#39;s jaw is required to remain wired for several weeks after the ORIF. While plating devices could be used in conjunction with TWM to dispense with IMF postoperatively, that technique would not solve the problems associated with the use of rigid metal plates. 
   The TWM is comparatively quick and easy to use because it simultaneously combines reduction and fixation, does not increase the complication rate, and has a low cost. This makes TWM an attractive alternative to current methods of mandibular internal reduction and fixation for simple and/or unstable fractures. In order to meet all the goals of mandibular fracture repair however, and reduce the problems encountered with existing internal fixation techniques using metal plates, utilize the benefits of TWM, and eliminate the need for IMF after surgery, a new device is desirable. 
   SUMMARY 
   An embodiment in accordance with the present invention is disclosed that provides an internal fixation plate having both a rigid retainer portion to assist in aligning opposing bone fragments and a flexible portion that will desirably conform to the cortical surface of the bone to which it is to be fastened without requiring the surgeon to attempt to bend the plate prior to fastening it to the bone. 
   An embodiment in accordance with the present invention includes a base having two non-linear arms, three fastener portions wherein two fastener portions are disposed along each arm and one fastener portion that is intermediate to the two other fastener portions. Each arm of the base contains a flexible portion and a retainer portion. The flexible portion of each arm is designed to allow the base to desirably conform to the surface of the bone. To assist in alignment and fixing the two sides of the fracture, the retainer portion is placed across the fracture line and against the two bone fragments. The intermediate fastener portion is fastened to the bone on one side of the non-comminuted, or simple fracture line and the non-intermediate fastener portions are fastened to the bone on the second side of the fracture line. 
   In particular, some embodiments use screws inserted through an aperture in a fastener portion to fasten the base to the bone. In one embodiment, one of the fastener portions includes a shelf that is adapted to slideably retain a base the surgeon slides under a previously placed screw. This channel eliminates the surgeon&#39;s need to align the base with the hole in the bone and insert a screw through a hole in the base. A base so engaged, may be released by sliding the shelf out from under the screw that is secured to the bone. An embodiment of the base is designed to be subcutaneously implanted and remain affixed to the bone fragments. 
   In some embodiments, the base can be used alone in a manner similar to use of a conventional internal fixation plate, where the surgeon manually reduces and aligns the fracture. Other embodiments are designed to allow the surgeon to use the benefits of the tension wire method to reduce and fixate the bone fragments and to obtain the benefits of the base. In such embodiments, two screw holes are placed normal to the line of the fracture, a screw is inserted into each one of each hole and the screws are tightened and then loosened slightly, to allow the shelf of the base to be slid under a first screw. The screw is tightened, thereby temporarily securing the base to the bone. A wire is then placed around a channel in the base and around the second screw. In this embodiment, the wire channel allows the surgeon to use the benefits of the tension wire method in combination with the benefits of the base by keeping the wire against the bony cortex to minimize undesirable moment forces upon the bony fragments. The wire is then tightened around the channel and around the base until the fracture fragments are properly aligned and apposed, and the second screw tightened. 
   A method in accordance with an embodiment of the present invention for treating a fracture of the mandible generally comprises the following steps: Making an incision to access the repair site; reducing and fixating the fracture using the TWM; drilling additional holes through the apertures in the distal fastener portions of the base and into the bone; inserting screws through the apertures in the base and fastening the flexible arms of the base to the bone. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is described with respect to particular exemplary embodiments thereof and reference is accordingly made to the drawings (which are not necessarily drawn to scale) in which: 
       FIG. 1  is a 3-dimensional view showing a fracture of the body of the mandible, and a typical conventional base; 
       FIG. 2  is a top view of a base according to and embodiment of the invention; 
       FIG. 2A  illustrates a typical bone screw; 
       FIG. 3  is a top perspective (labial side) view of an embodiment of the invention; 
       FIG. 4  is a bottom perspective view of an embodiment of the invention; 
       FIG. 4A  is a side view of an arm of an embodiment of the invention; 
       FIG. 5  is a side view of an embodiment of the invention; 
       FIG. 6  is a top view of an embodiment of the invention shown across a fracture line; 
       FIG. 7  is a top view of an embodiment of the invention shown in combination with a tension wire; 
       FIG. 8  is a bottom view of an embodiment of the invention shown in combination with a tension wire; 
       FIG. 9  a bottom view of an embodiment of the invention shown in combination with a tension wire; 
       FIG. 10  is a 3-dimensional view of a mandible with an embodiment of the invention; 
       FIG. 10A  is a 3-dimensional view of a mandible with an embodiment of the invention shown in combination with a tension wire; 
       FIG. 11  illustrates an embodiment of the invention; 
       FIG. 11A  illustrates an embodiment of the invention; 
       FIG. 11B  illustrates an embodiment of the invention; and 
       FIG. 11C  illustrates an embodiment of the invention. 
   

   DETAILED DESCRIPTION 
   The device of the present invention is discussed herein with reference to an embodiment to be used to fixate fragments of a fracture of the body of the mandible in their anatomically correct positions. It will be apparent however, that such a device is not limited to fractures of the body of the mandible, or to fractures of the mandible generally, but finds general application for internal fixation of fractures of other bones of the skeleton. 
     FIG. 1  illustrates the general anatomical areas of a mandible  112 . A typical conventional plate  98  is shown affixed to a fracture line  100 , here shown in the body of mandible  112 . If a fragment of the fracture moves towards the cheek or lips in the direction of arrow  96 , the fracture fragment is said to have moved in the buccal-labial direction. If a fragment of the fracture moves toward the tongue, i.e., in the direction of arrow  94 , it is said to have moved in the lingual direction. In practice, when a base, e.g.,  100 , is affixed to the surface of a mandible  112  in the manner shown in  FIG. 1 , the surface of the base  100  that is seen in that view faces away from the surface of the bone and towards the soft tissues of the cheeks. Here, we define the surface of a base  100  seen in  FIG. 1  to be the “buccal-labial” surface. 
     FIGS. 2-3 , illustrate an embodiment of the invention, in which a base  10  comprised of two non-linear arms  114 - 1  and  114 - 2 , each of which extends forwardly from an intermediate fastener portion or attachment location  104  and towards the distal fastener portions or attachment locations  106  and  108  respectively. The non-linear arms  114 - 1  and  114 - 2  are disposed about an intermediate fastener portion  104 . Each arm  114 - 1  and  114 - 2 , as shown, is of equal length and the arms  114 - 1  and  114 - 2  are disposed at an angle of 60° with respect to each other. Each arm  114 - 1  and  114 - 2  includes apertures  116 - 1 ,  116 - 2  and  116 - 3 , adapted to engage a screw, e.g.,  118  inserted through each one of apertures  116 - 1  and  116 - 2  respectively, suitable for affixing a base  10  to a portion of a patient&#39;s mandible  112 . In one embodiment, each arm  114 - 1  and  114 - 2  includes a flexible portion  110 . Although the embodiment illustrated in  FIGS. 2-3  show equal length arms  114 - 1  and  114 - 2  at a 60° angle, in other embodiments, the length of arms  114 - 1  and  114 - 2  are not necessarily equal and the angle of the arms  114 - 1  and  114 - 2  relative to each other may be at any acute angle, but would be most effective at a range of 45° to 90° relative to each other. In some embodiments, distal fastener portions  106  and  108  and intermediate fastener portion  104  is secured to the mandible  112  by a fastener such as an internal fixation screw, e.g., screw  118 , inserted through an aperture, e.g.,  116 - 1 ,  116 - 2 , and  116 - 3 , that is drilled or formed therein to receive a fastener such as a screw  118  in  FIG. 2A , to penetrate and attach to the bone. In one embodiment, standard bone screws known to persons skilled in the art, including internal fixation screws having approximate dimensions 2.0 mm by 4 to 6 mm, may be used. It is appreciated by those skilled in the art however that a pin, nail, brad, adhesive, or other fasteners are also suitable. The base  10  may be fastened to the mandible  112  by bio-absorbable material, in which the material selected for the fasteners should be such that the fasteners will take at least as long to be absorbed by the patient&#39;s tissues as the time required for osteosynthesis. In this embodiment, each fastener portion  106  and  108  is equidistant from an intermediate fastener portion  104 . However, it will be apparent to persons skilled in the art, that this is not required in other embodiments and that the fastener portions can be respectively positioned at a variety of positions along the arms  114 - 1  and  114 - 2 . In use, one embodiment is implanted subcutaneously through a small incision in the skin. 
   In one embodiment each aperture,  116 - 1 ,  116 - 2  and  116 - 3 , acts as a drill guide to enable a surgeon to accurately drill a hole into the mandible  112 , and place a fastener through the fastener portions  104 ,  106  and  108 , and into a mandible  112  without repositioning the base  10 . In other embodiments, only one or two of apertures  116 - 1 ,  116 - 2  and  116 - 3  will act as drill guides. 
   In some embodiments, best seen in  FIG. 3 , apertures  116 - 2  and  116 - 3  of each fastener portion  106  and  108 , contain a countersink  120 - 1  and  120 - 2 , respectively, the diameter of each countersink  120 - 1  and  120 - 2  can be adapted to accept screws of any desired shape or gauge. 
   In some embodiments best seen in  FIG. 3 , the intermediate fastener portion  104  contains a shelf  132 , which is sized and shaped to allow a threaded portion  128  of a screw, e.g.,  118 , to be slideably received by the shelf  132  such that the screw head  126  contacts with the buccal-labial surface of the shelf  132  of a base  10 . 
   Referring now to  FIGS. 4 ,  8  and  9 , the surface of an illustrated base  10 , is the bone-contacting, surface because, in practice, this surface faces toward the cortical surface of the bone. These embodiments include a retainer portion  130 , that contains at least one intermediate fastener portion  104 , the retainer portion  130  being continuous about the intermediate fastener portion  104  and along at least a part of each arm  114 - 1  and  114 - 2 . The retainer portion  130  is intended to contact the cortical surface of the mandible  112 . In one embodiment, the retainer portion  130  has a substantially constant thickness over its length. In one embodiment, the thickness of the retainer portion  130  is about 0.77 mm. Those skilled in the art however, will appreciate that the thickness of the retainer portion  130  is limited only by the strength of the materials used to construct the retainer portion  130  and the patient&#39;s acceptance of the base while it remains fastened to the bone. The retainer portion  130  is substantially inflexible and it is intended to cross the fracture line  100  and provide a rigid surface to assist in reducing the opposing fragments. In practice, the surgeon will position the bone-contacting surface of retainer portion  130  such that it crosses each side of the fracture line  100 , best illustrated in  FIG. 10 . Placing the retainer portion  130  across the fracture line  100  so that the retainer portion  130  overlaps the fracture line  100  restrains undesirable movement (displacement) in the lingual direction  94  of the fragment on the side of the fracture line  100  on which the intermediate fastener portion  104  is affixed. As a result of this overlap, the mandible fragments on opposite sides of the fracture  100  are effectively restrained against relative movement. 
     FIG. 9  illustrates a flexible portion  110  of each arm  114 - 1  and  114 - 2 , of an embodiment of the invention. The flexible portion  110  is susceptible to being bent and is intended to bend, during fixation of the base to the mandible  112  and during osteosynthesis. This characteristic is not present in conventional plates. Conventional internal fixation plates have a thickness in the ranges of 1.5 mm to over 2.0 mm. Surgeons using a convention internal fixation plate will use an instrument to bend and twist a conventional plate e.g.  98 , as illustrated in  FIG. 1 . 
   In contrast, the flexible portion  110  of an internal fixation plate in accordance with one embodiment of the present invention has a thickness over its length of about 0.25 mm, preferably in the range of about 0.2 mm to about 1.0 mm, best illustrated along line B-B′ in  FIG. 5 . This difference in thickness results in certain advantages over conventional internal fixation plates. In general, the flexibility, i.e., the amount of deflection or deformation that the flexible portion  110  will undergo as a result of a force (F) placed upon it, can be analyzed in accordance with the following equation: 
           δ   =         F   ⁢           ⁢     L   3         3   ⁢   E   ⁢       wh   3     12         =       4   ⁢   F   ⁢           ⁢     L   3         E   ⁢           ⁢     wh   3                 
is deflection
 
   where 
   δ is the width of the arm, 
   E is the Young&#39;s modulus of elasticity of the material of the flexible portion, 
   F is the amount of normal force exerted when tightening the screw, 
   H is the thickness of the flexible portion (or another lever) and, 
   L is the length of the arm. 
   Comparing the measure of flexibility (deflection) for flexible portion  110  with a conventional internal fixation plate with a thickness of 1.5 mm may be useful. Assuming that internal fixation plates are constructed of the same materials, i.e., stainless steel or titanium, the above equation shows that the flexible portion  110  on one embodiment of the proposed invention will be 216 times more flexible than a base of 1.5 mm thickness. Surgeons using a device in accordance with an embodiment of the present invention will notice this difference between the force required to flex the flexible portion  110  of base  10  and the force required to flex a convention internal fixation plate. 
   The flexible portion  110  of an internal fixation plate in accordance with one embodiment of the present invention has width (w) of about 2.25 mm, best illustrated along line A-A′ in  FIG. 7 , and the length of the arm (L) is in the range of 6 to 15 mm, best illustrated along line C-C′ in  FIG. 2 . Other embodiments will have differing dimensions for the flexible portion  110  such as from about 0.20 to 1.0 mm in thickness. 
   One advantage with some embodiments of the present invention is that little or no bending will occur in the retainer portion  128  relative to the bending that will occur in the flexible portion  110 . The flexibility of flexible portion  110  has the additional advantage in that it eliminates the difficulty encountered with prior metal internal fixation plates when, during surgery, the surgeon attempts to bend and shape a plate, e.g., plate  98  of  FIG. 1 , to conform to the surface of the bone. The increased flexibility of flexible portion  110  is also particularly advantageous in that this, flexibility allows the base  10  to conform to the contours of the mandible  112  during osteosynthesis, thereby ensuring that unwanted bone deformation does not occur. Another advantage of some embodiments, is that its low profile or thickness, as measured from the buccal-labial surface to the bone-contacting surface of about 1.37 mm, allows the plate to be left permanently in the patient. In other embodiments, the thickness range from about 1.1 mm to 1.5 mm. In considering thickness, a primary concern is acceptance by the patient. 
   Turning again to  FIGS. 3 and 4 , in one embodiment, collars  138 - 1  and  138 - 2  are disposed at a distal end of each arm  114 - 1  and  114 - 2  of the flexible portion  110 . The collars  138 - 1  and  138 - 2 , are of about equal thickness 1.37 mm, relative to the retainer portion  130 . In one embodiment, best shown in  FIG. 3 , an end of the flexible portion  110  terminates on the buccal-labial surface of a base  10 . However, persons skilled in the art will appreciate that the flexible portion  110  could also terminate on the cortical contacting surface, best seen in  FIG. 4A , or, at any place along a collar  138 - 1  and  138 - 2 . In still other embodiments, collars  138 - 1  and  138 - 2  are not required. In other embodiments (not shown), arms  114 - 1  and  114 - 2  include a fastener portion  106 ,  108 , along their lengths instead of at the distal end of the arm. 
   In one embodiment, as shown in  FIGS. 4 ,  5 , and  7 , a base  10  contains a wire channel or groove  136  that extends around the periphery of the rear of the base  10  and serves as a tension member receiving means to accept a tension member such as a wire  140 , that is used during a surgical procedure in which a surgeon desires to use the Tension Wire Method (TWM) of fixating the bone fragments. The term “tension wire” is used herein as a matter of convenience only. Any means for reducing the fracture is suitable. In another embodiment, the tension wire  140  is enclosed into base  10  while in other embodiments, the wire channel or groove is shaped in such a manner, e.g., a quarter circle, or by any other means, that forces the tension wire  140  to remain flush with the surface of the bone. The method of using the base  10  in conjunction with the TWM method will be explained in detail below. 
   Conventional linear plates function best when placed normal to the fracture line. In this orientation, the length of the linear plate performs like a beam with fully fixed ends. The finite element analysis of a device in accordance with an embodiment of the invention demonstrated that such a device withstands the stresses, including mastication, exerted during osteosynthesis. That is, stresses on an embodiment of the base, were well below the stresses that would produce deformation or failure in the various components of the device. One advantage, therefore of using a device in accordance with the present invention, is that the surgeon can choose an internal fixation base having flexibility without sacrificing the strength required to fix the fragments against the forces of mastication. 
   A device in accordance with embodiments of the present invention may be made in full or in part from any appropriate bio-compatible material such as titanium or stainless-steel. The fasteners may also be comprised of any bio-compatible material, as long as the material selected for the screws is such that the screws will take at least as long to be absorbed by the patient&#39;s body as the time necessary for healing of the fracture. It will be appreciated by those skilled in the art, however, that other materials having suitable performance and biocompatibility characteristics may be used in other embodiments. Although an embodiment of the invention has been described with respect to a v-shaped base, other embodiments can use bases or plates of other shapes. For instance,  FIG. 11  shows a triangle shaped base, while  FIG. 11A  shows a “U” shaped base,  FIG. 11B  a base with arms of unequal length, and  FIG. 11C  a base with more than three attachment locations. Each shape may be suitable for embodiments of the invention. As will be understood by persons skilled in the art, shapes other than those shown will also be suitable for various embodiments of the invention. 
   A method for treating a fracture of the mandible on a patient according to the present invention comprises the following steps. Referring now to  FIG. 10 , an incision is made and dissection performed (not shown) for access to the fracture line  100 . The side of the fracture line on which there is greater lingual displacement is located and a first hole  142  is drilled normal to, and about 4 to 6 mm from, the fracture line  100 . A first screw, e.g.,  118 , is inserted through an aperture, e.g.,  116 - 1 , in the intermediate fastener portion  104  and into the first hole  142  drilled into the bone. Grasping the base  10 , the surgeon orients each arm  114 - 1  and  114 - 2  in such a manner that the retainer portion  130  of base  10  crosses the fracture line  100 . The first screw is tightened thereby affixing the intermediate fastener portion  104  to one side of a fracture line  100  and reducing the relative buccal-labial displacement of the mandibular bone on the side opposite to intermediate fastener portion  104 . After satisfactory reduction is assured, an aperture, e.g.,  116 - 1 , is used as a guide to drill a second hole into the mandible, and a second screw, e.g.,  118 , is placed into the second hole  144  just drilled with the screw so placed then tightened. This procedure of drilling holes and placing screws is repeated for a third hole  146 . In some embodiments having more than three apertures, the procedure of drilling and placing screw is repeated for as many screws as desired. 
   Turning now to  FIG. 10A , a device according to an embodiment of the present invention may also be used in combination with the tension wire method (TWM). A method for treating a fracture of the mandible on a patient according to an embodiment of the present invention using TWM, comprises the following steps: An incision and exposure (not shown) is made for access to the fracture site. The side of the fracture line on which there is greater lingual displacement is located and a first hole  142  and a second hole  144  are drilled normal to and about 4 to 6 mm from the fracture line  100 . A first screw e.g.,  118  is placed in the first hole  142  in the mandible and a tension post  119 , which may be a second screw, is placed into the second hole  144  in the mandible, both screws are tightened and both screws are reversed about two turns. A bone-contacting surface of the retainer portion  130  of an embodiment containing a wire channel  136 , best seen in  FIGS. 3 ,  4  and  5 , is inserted under the screw head  126  of the screw placed on the side of the fracture with lesser buccal-labial displacement relative to the opposing fragment, thereby slideably engaging the shelf  132  with the screw head  126  of the first screw so that the retainer portion  130  crosses the fracture line  100 . The first screw is then tightened onto the shelf  132  thereby affixing a base  10  to one side of the fracture line  100 . A tension means, which may be a wire  140 , is then placed around wire channel or groove  136  of base  10  and also around the second screw. The surgeon then tightens the tension wire  140  around the wire channel  136  and the second screw. By tightening the tension wire  140 , and the second screw, the surgeon properly reduces and fixates the fragments of the fracture simultaneously and orients base  10  in such a manner that the retainer portion  130  of the base  10  crosses the fracture line  100 . Using apertures  116 - 2  and  116 - 3 , in fastener portions  106  and  108  respectively, that have been placed over the same side of the fracture on which the second screw was placed as guides, the surgeon then drills holes through each of the apertures  116 - 2  and  116 - 3  and inserts, respectively, a third screw and a fourth screw through each one of the apertures  116 - 2  and  116 - 3  and tightens the third and fourth screws to permanently affix a base  10  to the patient&#39;s mandible. The hole for the first fastener portion is drilled and the first screw placed before the next hole is made and the next screw placed. In embodiments having more than three apertures, this procedure of drilling holes and placing screws is repeated for as many screws as is desired. 
   It should be understood that the particular embodiments described above are only illustrative of the principles of the present invention, and various modification could be made by those skilled in the art without departing from the scope and spirit of the invention, thus, the scope of the present invention is limited only by the claims that follow.