Mandibular Border Retractor and Method for Fixating a Fractured Mandible

The present invention relates to a mandibular retractor and method for fixating a fractured mandible. More particularly, the invention relates to a mandibular retractor and fixation method which improves the surgeon's access and visibility of the surgical site and which allows a surgeon to fixate a fractured mandible, reducing or eliminating the need for a surgical assistant.

The treatment of bone fractures in craniomaxillofacial regions generally proceeds by reducing the fractured bone to its anatomically correct position, and thereafter fixing the bone in place. This procedure is known as an open reduction/internal fixation or "ORIF". In an ORIF, the bone may be fixed in place either by interosseous wiring or by the technique of miniplate (or bone plate) osteosynthesis. See Greenberg, A. M., editor Craniomaxillofacial Fractures: Principles of Internal Fixation Using the AO/ASIS Technique, Springer Verlag, New York (1993). In either case, holes must be drilled into the bone for receiving the interosseous wire or screws for holding the bone plates to the bone.

FIG. 1 shows a fractured mandible. The mandible M has a fracture F. The patient's skin S is shown in cutaway view. The mandibular nerve N runs through the mandible M and exits into the skin S at an anterior portion of the mandible, where it becomes the mental nerve ME, which is a delicate structure. The fractured mandible is treated with an ORIF procedure. The present invention is explained with respect to bone plate osteosynthesis, but a person skilled in the art will readily understand that the disclosure is equally applicable to interosseous wiring.

FIGS. 2 and 2A show a greatly enlarged bone plate P useful in the treatment of mandibular fractures. Numerous different configurations of the bone plate may be used depending on the size and shape of the fracture and bone structure to be reduced. The bone plate P is just one example of a suitable bone plate. The bone plate P consists of a chain-like body 41 having holes 42 therein. Each of the holes 42 is countersunk with a beveled edge 43 so that the holes 42 are adapted to receive surgical screws (not shown) and to retain the reduced bone in place until the bone heals. The bone plate holds the bone structure together so that it can heal.

An exemplary prior art intraoral (i.e., through the mouth) mandibular ORIF procedure is described as follows. As shown in FIG. 3A, a mandible M has a fracture F. The patient's skin S and tongue T are also shown. An incision SI is made through the patient's cutaneous region near the fracture F. A second incision, referred to here as the oral incision OI, is made in the buccal vestibule. The oral incision OI is generally V-shaped and runs parallel to the mandible M, as shown in FIG. 3B. Care is taken to locate and preserve the mental nerve. The, presence of the mental nerve at the anterior portion of the mandible M confines the area that the surgeon can access. Thus, the surgeon is confined to a small space in which to operate and accommodate surgical instruments.

As shown in FIG. 3A, two right angle retractors LR retract the mouth so that the fracture may be viewed. As seen in FIG. 3C, the retractors LR pull the oral incision OI anteriorly and posteriorly (indicated by the opposing horizontal arrows on the retractors LR), causing tension in the V-shaped oral incision which tends to pull the lateral aspects towards each other (indicated by the vertical arrows), thus tending to limit the surgeon's access to the incision.

The mandible is reduced to its anatomically correct position. This typically requires a retractor to access the fracture F. After the mandible is successfully reduced, the bone should be fixed in its proper position to heal. This is typically done with either interosseous wiring or bone plate osteosynthesis. This requires drilling holes in the mandible. This typically requires (1) retracting the tissue from the mandible to view the surgical area; (2) holding a bone plate in position across the fracture; (3) holding a drill depth guide to prevent drilling too deeply, or through, the mandible; and (4) operating the drill.

FIG. 3D illustrates how a conventional intraoral mandibular fixation is performed using the miniplate osteosynthesis technique. A trocar or cannula T is inserted into the incision SI. A bone plate P is positioned across the fracture, typically by one of (1) a surgical assistant who introduces the plate P through the patient's mouth and holds the plate in position with a surgical instrument such as a clamp; (2) holding the plate in place on the tissue below; or (3) sitting the plate on the retractor's base. The surgeon then inserts a drill through the trocar T in incisions SI, OI into alignment with a hole in the bone plate P. Once aligned, the surgeon drills a hole into the bone and then screws a screw into the hole in the bone plate P, thus, affixing the bone plate P to the mandible M. Alternatively, a threaded opening may be tapped in the bone prior to the introduction of the screw. In such a case, a tap is applied to the hole drilled into the bone before the screw is applied. At least one screw is placed on each side of the fracture in order to stabilize the bone. No retractor is located behind the mandible during the fixation.

This procedure requires three or more "hands" to perform; that is, two hands are needed to retract the mouth. The surgeon's hands are occupied with the trocar T and the drill, tap, or screwdriver. Additional hands may be needed to hold the plate P in position. This is disadvantageous for several reasons. First, the anterior and posterior retraction limits the surgeon's access to the oral incision, limiting the surgeon's view of and access to the surgical site. Second, the more "hands", instruments, or other obstructions in the area of the surgical site (here, at least two hands are needed to hold the retractors) reduces the surgeon's already limited visibility of the surgical site. There is the additional expense of a surgical assistant. Surgical assistants are relatively costly to the patient. Many insurance companies are searching for ways to reduce the expense of surgical assistants and some have eliminated insurance payments for the assistant altogether for certain procedures, leaving the expense of the assistant on the patient.

The prior art retractors and surgical methods, while useful, are not entirely satisfactory for the procedure described above.

Accordingly, it is an object of the present invention to provide a mandibular border retractor which reduces or eliminates the role of a surgical assistant in mandibular ORIF procedures.

A further object of the invention is to provide a retractor which improves the ease of an intraoral fracture reduction, thus reducing the likelihood of the patient undergoing an extraoral (transcutaneous) approach. The extraoral approach requires longer operating and hospitalization times and increases the likelihood of complications.

It is a further object of the present invention to provide a retractor that allows the surgeon to reduce the mandible, retract and view the surgical site, and hold the bone plate in position with a single hand, leaving the other hand free to operate surgical instruments.

It is yet a further object of the invention to provide a retractor which retracts the lateral aspect of an oral incision, thereby not placing tension on the incision which would limit the surgeon's access to surgical site.

It is yet another object of the present invention to provide a mandible retractor having an aperture through which retracts of the lateral aspect of the oral incision and also permits a drill guide, drill, or other surgical instrument to access the surgical site.

It is yet a further object of the present invention to provide a retractor which includes an integral surgical instrument holder.

It is yet a further object of the present invention to provide a clamp for grasping or reducing a mandible.

These and other objects of the invention are achieved by the present invention. The present invention is a mandibular retractor which is inserted into the patient's mouth and has a curvilinearly-shaped retractor blade to retract the cutaneous region away from the mandible laterally. The retracting blade has an aperture which allows surgical instruments to be inserted through an incision in the cutaneous region, through the aperture, and to the mandible. The retractor also has an arcuate distal portion which may be located under and behind the mandible. The retractor allows a surgeon to retract with one hand and view the surgical site by looking down in to the mouth. The surgeon's other hand is free to operate surgical instruments such as a drill or screwdriver. No additional retractors are necessary, reducing the number of hands in the area of the surgery. The surgical assistant's role is reduced or eliminated.

The retractor may also include a shelf on the retracting blade below the aperture to hold a bone plate. This shelf acts as a carrier so that the bone plate may be positioned across the fracture when the retractor is inserted into the mouth and the tip is located behind the mandible.

The retractor may optionally include tapered side flanges to retract tissue away from a lateral end of the oral incision. The retractor may also optionally include a stabilizing arm which is located outside of the patient's mouth during the operation. The stabilizing arm may have an aperture aligned with the retractor blade aperture to permit surgical instruments to be inserted. The stabilizing arm may also include an adjustable surgical instrument retaining screw for holding surgical instruments in position. The retractor may also optionally include a moveable surgical instrument guide in the retractor blade aperture for holding surgical instruments in position.

The retractor according to the present invention may also be configured as a clamp which may, for example, be used to remove bone fragments. The retractor may also be configured as a reduction clamp which applies pressure on an opposite side of the mandible to reduce the fracture or to firmly hold a bone plate in place.

These and other objects and features of the invention will become apparent from the following drawings, wherein:

FIG. 1 illustrates a fractured mandible;

FIG. 2 illustrates a prior art bone plate for use in securing bone fragments together;

FIG. 2A is a cross sectional view of the bone plate of FIG. 2;

FIGS. 3A-3D illustrate a prior art intraoral ORIF procedure for the fractured mandible of FIG. 1;

FIG. 4 is a perspective view of one embodiment of the retractor according to the invention;

FIG. 5 is a side elevational view of the retractor of FIG. 4;

FIG. 6 is a front view of the retractor of FIG. 4;

FIG. 7 is a back view of the retractor of FIG. 4;

FIG. 8 is a top view of the retractor of FIG. 4;

FIG. 9 is a bottom view of the retractor of FIG. 4;

FIG. 10 is a perspective view of another embodiment of the retractor according to the invention;

FIG. 11 is a side elevational view of the retractor of FIG. 10;

FIG. 12 is a front view of the retractor of FIG. 10;

FIG. 13 is a back view of the retractor of FIG. 10;

FIG. 14 is a top view of the retractor of FIG. 10;

FIG. 15 is a bottom view of the retractor of FIG. 10;

FIG. 16 is a perspective view of the retractor of FIG. 10 with a bone plate inserted on the shelf;

FIG. 17 illustrates a cross sectional view of the proximal end of the retractor of FIG. 10 used during a fixation of a fractured mandible;

FIG. 18 is a perspective view of another embodiment of a retractor according to the present invention;

FIG. 18A illustrates a top view of the retractor of FIG. 18 inserted in an oral incision;

FIG. 19 is a perspective view of another embodiment of a retractor according to the present invention;

FIG. 20 is a perspective view of another embodiment of the retractor according to the present invention;

FIG. 21A is an exploded view of an alternative embodiment of the retractor of FIG. 20 having a surgical instrument retaining screw;

FIG. 21B is a cross sectional view of the embodiment of FIG. 21A;

FIGS. 22A and 22B illustrate an alternative embodiment of the surgical instrument retaining screw of FIG. 21A and 21B;

FIG. 23 illustrates a mandibular retractor having sliding drill sleeve according to one embodiment of the present invention;

FIGS. 24A and 24B illustrate two alternative embodiments of sliding drill sleeves;

FIG. 25A is a cross sectional view of the retractor and sliding drill sleeve of FIG. 22, taken along line 25A--25A;

FIG. 25B is a cross sectional view of the sliding drill sleeve of FIG. 24B in place on a retractor;

FIG. 26 is a side, view of a sliding drill sleeve having a drill guide extending through it;

FIGS. 27A and 27B illustrate alternative embodiments of sliding drill sleeve guides;

FIG. 28 is a cross sectional view of the drill sleeve guide of FIG. 27A and a screwdriver tightening a set screw;

FIG. 29 is a perspective view of a retractor and clamp according to the present invention;

FIG. 30 is a side elevational view of the retractor and clamp of FIG. 29;

FIG. 31 is a side view of the retractor and clamp of FIG. 29 in use;

FIG. 32 is a perspective view of a retractor and reduction clamp according to the present invention;

FIG. 33 is a side elevational view of the retractor and reduction clamp of FIG. 32;

FIG. 33A is a side elevational view of the retractor and reduction clamp of FIG. 32; and

FIG. 34 is a side view of the retractor and reduction clamp of FIG. 32 in use.

A mandibular retractor 50 according to one embodiment of the present invention is shown in FIGS. 4-9. A handle 52 is located at the proximal end of the retractor 50. A retracting blade 54 is connected to the distal end of the handle 52. The retracting blade 54 comprises a curved portion 56 at the proximal end of the retractor blade 54, an arcuate portion 58 having a tip 59 at the distal end of the retractor blade 54, and an aperture 60 defined in the retracting blade 54 located proximally from the tip 59.

The curvature of the retracting blade according to the present invention is designed to be inserted into the patient's mouth and to hold the reduced mandible in place and retract the surgical site. The curved portion 56 has a long, gradual curvilinear shape. This curvature pulls the cheek in a direction away from the mandible sufficiently to allow observation of the surgical site. This shape allows retraction of the lateral aspect of the V-shaped oral incision, that is, in a direction generally perpendicular to the mandible. Retracting in this direction opens the V-shaped oral incision OI (see the arrow in FIG. 17.) The arcuate tip 58 is generally semi-circular and is designed to fit under and behind the mandible. Preferably, the tip does not extend too far upwards, because it may be impeded by soft tissue.

Another embodiment of the present invention is shown in FIGS. 10-16. A mandibular retractor 50' comprises a handle 52 and a retracting blade 54. In this embodiment, the retracting blade comprises a curved portion 56, an arcuate tip 58, an aperture 60 located proximally from the tip 58, and a shelf 64 located distally of the aperture 60. The shelf 64 is shaped to conform snugly to a bone plate P. As shown in FIG. 16, a bone plate P may be inserted into the shelf 64 before the retractor is placed in the patient's mouth. Thus, the shelf 64 operates as a carrier to locate the plate P at the fracture and hold it in place when the retractor 50' is positioned with respect to the mandible. The position of the shelf 64 between the tip 58 and the aperture 60 allows the bone plate holes 32 to align with the aperture 60. Thus, a straight line exists from the skin incision, through the retractor aperture 60 and the bone plate hole 32 to the mandible, as indicated by the arrow in FIG. 16. Also, there is no need for additional assistants or surgical instruments to position or hold the plate against the mandible.

The mandibular retractor according to the present invention is used as illustrated in FIG. 17 and described as follows. A skin incision SI and a V-shaped oral incision OI are made in the region of the fracture F. If the fracture is located anterior to the mental nerve, there may be no need for the skin incision and the procedure may be performed completely intraorally. If, as illustrated in FIG. 17, the fracture is posterior to or in the region of the mental nerve, a skin incision may be necessary. The retractor 50 is inserted into the patient's mouth and the arcuate portion 58 and tip 59 are manipulated through the oral incision OI to be positioned under and behind the fractured mandible M. The retractor is positioned so that the aperture 60 is aligned with the skin incision SI. The retractor is used to reduce the mandible M to its correct anatomical position. The patient's cutaneous region (skin S) may be retracted away from the mandible M in the direction of the arrow so that the surgeon may observe the surgical site by looking down into the patient's mouth. This retractor pulls the oral incision laterally, thus opening the oral incision OI, providing good visibility of the surgical site.

The surgeon places a bone plate P into position across the fracture. This may be done in the conventional fashion by having an assistant hold it in position, having the tissue support it, or having it sit on the retractor's base. Alternatively, the shelf 64 may be used. The surgeon's free hand may be used to operate a drill guide D, drill, screwdriver, or other surgical instrument. As is seen in FIG. 17, the aperture 60 allows the surgical instrument (e.g., the drill guide D) to extend through the retracting blade 54 to contact the bone plate P. A drill or other surgical instrument may then be used to drill a hole, tap a thread, screw in a screw, or otherwise access the mandible M.

FIGS. 18 and 19 show further embodiments of the present invention. Retractors 50"' and 50"" are substantially the same as the retractor illustrated in FIGS. 4-9, except for the addition of FLANGES 65"' and 65"". A retractor having FLANGES 65"', 65"" is used to further retract one side of the oral incision OI, preferably the anterior portions, thus further opening the site. As seen in FIG. 18A, the flange 65"' further opens oral incision OI. When the flange is used to retract the anterior portion of the oral incision OI, the wing also protects the mental nerve, which exits at an anterior portion of the mandible. The flanges 65"', 65"" are preferably tapered for a wide portion near a proximal end of the retracting blade 54 to a narrow portion near a distal end of the retracting blade 54. This taper permits the flanges to get close to the mandible M.

FIG. 20 illustrates another embodiment of a mandible retractor 50""' according to the present invention. The mandible retractor 50""' comprises a handle 52, a retracting blade 54, and a stabilizing arm 70. The stabilizing arm 70 initially extends in a direction generally perpendicular (preferably extending out at an angle between 30 and 100 degrees) to the retracting arm 54, to form roughly an inverted Y shape. The stabilizing arm 70 has a central portion 71 A which is generally parallel to the retracting blade 54 and a curved tip 71 B which curves in a direction opposite the arcuate portion tip 59 of the retractor blade. The stabilizing ann 70 includes a stabilizing arm aperture 72.

In use, the stabilizing arm 70 is located outside the patient's mouth and the stabilizing arm aperture 72 is aligned with the retracting blade aperture 60. The stabilizing arm aperture 72 stabilizes a surgical instrument, such as a drill guide D (shown in broken lines in FIG. 20). The instrument is stabilized by a bottom portion 74 of the stabilizing arm aperture 72. The instrument then extends through an incision in the patient's cutaneous region before extending through the aperture 60 in the retracting blade to contact a bone plate or the mandible.

FIGS. 21A and 21B illustrate another embodiment of the mandibular retractor of FIG. 20. This embodiment includes a stabilizing arm 70' which further includes a retaining screw mechanism 79 for retaining a surgical instrument, such as a drill guide, to be inserted through the apertures 72, 60. The retaining screw mechanism 79 includes a knob 80, a shaft 82, an adjustable retaining sleeve 84, and a surgical instrument retaining frame 86. The frame 86 has an open area 87 through which an instrument may be inserted. As illustrated in FIG. 21B, the shaft 82 includes a first threaded portion 88 that meshes with a second threaded portion 90 within the stabilizing arm 70'. The bottom of the shaft includes a disc 92 which is rotatably held in a slot 94 within the adjustable retaining sleeve 84. The sleeve 84 and disc 92 are free to rotate with respect to each other. The bottom exterior of the retaining sleeve 84 has a third threaded portion 96 that meshes with a fourth threaded portion 98 within the instrument retaining frame 84.

In use, the height of the retaining frame 86 is adjusted by turning knob 80. The intermeshing between the first and second threaded portions 88, 90 raises and lowers the entire shaft assembly comprising shaft 82 and sleeve 84. Because the retaining frame 86 is connected to the sleeve, 14, it is raised and lowered along with the shaft 82. However, because the disc 94 and sleeve 84 are free to rotate with respect to each other, the rotation of the knob is not translated to the third and fourth threaded portions 96, 98. A drill guide or other surgical instrument may be inserted into the opening 87 of the frame 86 and the adjustable sleeve 84 may be raised or lowered to snugly hold the drill guide in the frame 86. This is accomplished by rotating the sleeve 84. The rotation causes the intermeshing between the third and fourth threaded portions 96, 98 to raise and lower the bottom tip of the sleeve 94 within the open area 87. This permits the use of surgical instruments having a variety of diameters. Again, because the disc 94 and the sleeve 84 are free to rotate with respect to each other, the rotation of the sleeve 84 is not translated to the shaft 82.

FIGS. 22A and 22B illustrate an alternative retaining screw mechanism 79'. This alternative mechanism has a knob 80 connected to a first shaft 82. The shaft is fixedly connected to the retaining frame 86. Turning knob 80 raises and lowers the retaining frame 86 as described above. A second knob 100 is connected to second shaft 102 which extends through the stabilizing arm 70' at a direction generally perpendicular to the first shaft 82. The second shaft 102 ends in a fifth threaded portion 104 which meshes with a sixth threaded portion 106 in a side of the retaining frame 86. Turning knob 100 moves a tip 108 of the second shaft 102 within the open area 87 to permit the use of a variety of different diameter surgical instruments.

The mandible retractor 50""' illustrated in FIG. 20 also includes a suction fitting input 110 and a fiber optic input 112. The suction extends through the handle 52 via a channel 114 and down the retracting blade 54 through a tube 116 to supply suction at the surgical site. The suction tube 116 should be positioned to be out of the way of a bone plate mounted on shelf 64. An optical fiber 118 extends through the handle and down the retracting blade 54 to supply light to the surgical site.

FIGS. 23-26 illustrate two embodiments of a moveable surgical instrument guide, for a drill sleeve or other instrument. FIG. 23 illustrates a retractor blade 54' having an aperture 60. A guide 120, having a body 121 defining a hole 122, is slidably mounted in a groove 124 in the retractor blade side wall 125 defining the aperture 60. The guide 120 is shown in broken lines at other positions within the aperture 60.

Two alternative guide configurations 120, 120' are illustrated in FIGS. 24A and 24B. FIG. 24A shows the moveable guide 120 of FIG. 23. The guide 120 comprises a body 121 defining a hole 122 and two side flanges 126 for extending into the grooves 124 in the retractor blade 54'. FIG. 23B shows a second configuration of moveable guide 120' for use with a retractor blade not having a groove. This guide 120 comprises sidewings 130 which extend from the top and bottom of the sides. These sidewings 130 define two channels 128. The channels 128 surround the retractor blade sidewalls 123, so that the sidewalls 123 extend through the channels 128.

The cooperation between the guides 120, 120' and the retractor blades 54, 54' are illustrated in FIGS. 25A and 25B. FIG. 25A is a cross sectional view of the retractor blade of FIG. 23. The guide side flanges 126 are within the grooves 124 in the sidewalls 125. FIG. 25B shows the wings 130 extending beyond the sidewalls to hold the guide 120' in position. Both configurations of the guide 120, 120' are maintained in a selected position by friction between the guide and the retractor blade.

FIG. 26 illustrates a drill sleeve D inserted into a moveable guide 120. The hole 122 has a diameter slightly larger than the diameter of the drill sleeve D, thus allowing the drill sleeve to be manipulated to a variety of angles. The drill sleeve D is shown in several positions within the guide 110 in broken lines.

FIGS. 27A, 27B, and 28 illustrate further alternative embodiments of the moveable guides. FIG. 27A shows a guide 120" having tabs 134 which expand outwardly when screw 136 is screwed down between the tabs 134. The tabs engage an inner wall of groove 124 (shown in FIG. 23) to hold the guide 120" in place. FIG. 27B shows a guide 120"' having curved tabs 138 which expand when screw 136 is screwed down between the tabs 138. The expansion of tabs 138 also causes the body 121 to rock about pivot points 139 causing a gap 140 in the bottom of the guide to narrow the hole 122, thus tightening around any instrument inserted into hole 122. FIG. 28 shows how screw 136 is tightened. A screwdriver 140 is inserted down into the aperture 60 to screw set screw 136. The curvilinear shape of the curved portion 56 allows easy access to the top of the screw 136.

FIGS. 29-31 illustrate a clamp 200 according to the present invention. The clamp comprises a retractor arm 210 and a clamping arm 220. The retractor arm 210 comprises a handle 252 having a finger ring 253, and a retracting blade 254. The retracting blade 254 has a curved portion 256, an arcuate portion 258, and an aperture 260 defined by the retracting blade. The curved portion 256 and arcuate portions 258 have substantially the same shapes as described above in relation to FIGS. 4-9. The retracting arm 210 also has a first set of grasping teeth 270 located proximally of the aperture, and half of a standard hemostat ratchet 272. The clamping arm 220 has a handle 282 with a finger ring 283 and the other half of the hemostat ratchet 274. The distal end of clamping arm 220 is preferably angled with respect to the proximal end to provide better contact with the mandible, as illustrated in FIG. 31. Near the distal end of the clamping arm 220 is a beak 290 having a second set of clamping teeth 291. The beak may be made of stainless steel, nitinol, or tungsten carbide and may optionally be removable. The arms 210, 220 are pivotally connected by a swivel pin 294.

FIG. 31 illustrates the clamp 200 in use. The clamp 200 is particularly useful in removing broken pieces of mandible bone or during a sagittal ramis osteotomy. The arcuate portion 258 of the retracting arm 210 is positioned under and behind a broken piece M' of mandible M. The clamping arm 220 is swung into position by pulling up on ring 283 to cause the second set of clamping teeth 290 to contact a surface of the broken piece M'. The pressure of the teeth 290 pushes the broken piece against the first set of clamping teeth 270 on the retracting arm 210. The clamp may be held in place by locking the hemostat ratchet 272, 274. This provides the surgeon with a firm hold on the piece, which can now be easily removed or held in place to be fixated.

FIGS. 32-34 illustrate a reducing clamp 300 according to the present invention. The reducing clamp 300 comprises a retractor 310 and a reducing clamp arm 320. The retractor is substantially the same as described with respect to FIGS. 4-9, or alternatively may have a shelf 364 for holding a bone plate. The retractor includes a handle 352 and a retracting blade 354. The retracting blade has a curved portion 354, an arcuate portion 358, and an aperture 360 defined in the retracting blade 354. The retractor may also have half of a standard hemostat ratchet 372. The reducing clamp arm 320 has a handle 382 with a finger ring 383 and the other half of the hemostat ratchet 374. The proximal end of the reducing clamp arm 320 has a straight portion 384 and a reducing plate 386 having a set of clamping teeth 390 facing the retracting blade 354. The second set of clamping teeth 390 may be sharp, as shown here, for direct contact with bone, or may be blunt, atraumatic teeth for contact with mucosa. The reducing plate 386 is preferably angled with respect to the straight portion 384. The reducing plate 386 may be narrow or broad. The preferred breadth depends on the nature of the fracture and bone structure. The reducing plate 386 may preferably be made of stainless steel, nitinol, or tungsten carbide and may optionally be removable. The angled joint 385 may be either permanently fixed or adjustably connected at various angles. The arms 310, 320 are pivotally connected by a swivel pin 394.

FIG. 33A shows a reducing plate 386 having blunt, atraumatic teeth 390'. This embodiment also includes a wing nut mechanism 392 capable of retaining the clamping arm 320 in position without the surgeon continuously pulling up on finger ring 383.

FIG. 34 illustrates the reducing clamp 300 in use. The clamp 300 is particularly useful in reducing a fractured mandible. A bone plate P is inserted into the shelf 364. The arcuate portion 358 of the retracting arm 310 is positioned under and behind the mandible M. The reducing clamp arm 320 is swung into position by pulling up on ring 383 to cause the clamping teeth 390 to contact a posterior surface of the mandible M. The pressure of the teeth 390 pushes the mandible against the plate P. This presses the fractured mandible flat against the plate P by clamping the medial aspect of the incision. The reducing clamp 300 may also be used to hold a bone plate firmly in place. The clamp may be held in place by locking the hemostat ratchet 372, 374.

The mandibular retractors described herein are preferably made of stainless steel or other material suitable for surgical use.

While the invention has been described by the reference to specific embodiments, this was for purposes of illustration only and should not be construed to limit the spirit or the scope of the invention. For example, a person of ordinary skill in the art recognizes that the retractor according to the present invention may be used for procedures other than an ORIF and may be used on bones other than the mandible.