PLATING OF MANDIBULAR FRACTURES. T. G. BATTERSBY, F.D.S. Nottingham General Hospital

Transcription

1 PLATING OF MANDIBULAR FRACTURES EXPERIENCES OVER A TWELVE-YEAR PERIOD T. G. BATTERSBY, F.D.S. Nottingham General Hospital OPEN reduction of otherwise irreducible mandibular fractures is now well-established surgical practice (Gibson and Allan, 1956). Ward (1963) advocates open reduction of fractures of the mandible as the treatment of choice. But he goes on to say: 'The use of malleable stainless steel wires to join the fractures bones together has rather superseded the use of bone plates and screws. It is invariably supplemented by intermaxillary fixation... ' Thoma (I963), however, is of the opinion 'that more secure fixation can be obtained by means of bone plates than is possible by trans-osseous wiring. Wiring mainly prevents distraction of the fragments whereas plating also eliminates overriding and vertical displacement.' But he says that a bone plate alone should not be relied upon for the immobilisation of the fracture; the jaws should be immobilised in addition. Our experience with bone plates has shown that in the vast majority of cases no additional intermaxillary fixation is necessary. In x95 o at the International Dental Congress in London, Case, an Australian, demonstrated the use of metacarpal plates and screws adapted for treatment of edentulous fractured mandibles and advocated no additional intra-oral fixation. Reference to the use of Vitallium metacarpal plates and screws as an alternative to inter-osseous wiring where removal of a large fragment of bone from the lower border of the mandible made it impossible to wire the remaining fragments satisfactorily, was made by Rank et al. (1954). Until recently, the use of bone plates and screws in jaw surgery had few advocates because the size and bulkiness of the orthopaedic plates at our disposal provoke a reaction on the part of the host. The bulk of a Sherman plate used for fixation of a mandibular fracture almost invariably leads to sequestration, and the screws are of such a size that they are likely to encroach upon the inferior dental canal (Fig. I). MATERIALS The development of a chrome-cobalt-molybdenum alloy by the Austenal Laboratories of America has provided us with an inert material, well tolerated by the human tissues, and the design of the plates and screws is such that their bulk is reduced to a minimum. The London Splint Company market their drills, plates, screws, etc., and we are indebted to Roberts (r964) for suggesting modification in the design of the original metacarpal plates so that their usefulness is extended. The addition of larger plates to the range permits more width between the two inner screw holes and this plate is of use in very oblique fractures (Fig. 2). The twist drills used to tap the bone prior to insertion of the screws, are mounted for use in a dental handpiece. 194

2 PLATING OF MANDIBULAR FRACTURES 195 It is essential that all materials used, the drill, the screws and plate, and the screw driver, be of compatible material to eliminate the possibility of an electrolytic action causing bone necrosis. FIG. I A and B Sherman plate in situ and sequestration caused by its bulk. INDICATIONS FOR OPEN REDUCTION AND PLATING OF THE MANDIBLE According to Gibson and Allan (1956) these are: (I) Displacement to upset the bite and lead to non-union. (2) Anaesthesia of the lower lip in association with a displaced fracture anywhere in the course of the inferior dental nerve. More specific indications are: (I) Reduction and fixation of a mobile edentulous posterior fragment with interposition of muscle fibres. (2) Bilateral fractures of the body of the mandible, especially edentulous ones which are so unstable. (3) Bilateral fractures of the symphysis mandibularis where the contraction of the mylohyoid muscles causes medial displacement of both fragments with overriding of the bone ends (Ptumpton & Crawford, 1955). (4) Neuro-surgical involvement. In cases of head injury, the absence of obstructing apparatus is desirable to the neuro-surgeon and to the Anaesthetist for ensuing operations (Hayton-Williams, 1958). Nursing of a restless patient is simplified by the absence of intermaxillary fixation, and oral hygiene more easily attained. In a review of results of delayed jaw fracture treatment, Hayton-Williams (196o) found that delaying reduction and fixation of an unfavourably sited mandi-

3 I96 BRITISH JOURNAL OF ORAL SURGERY bular fracture beyond three days may lead to infection and long-delayed union. Our experience confirms this view, and if a mandible is to be reduced and plated, the sooner it is done the better. If there is an alternate choice of treatment necessitating intermaxillary fixation, patients are always asked which method they would prefer. Invariably they elect for open reduction and plating with the prospect of mandibular movement in the immediate post-operative stage. FIG. 2 Showing range of plates employed and screwdrivers made of vitallium. Many of these plates are inserted via an intra-oral approach, including fractures proximal to the mental foramen, thus eliminating a scar. If there is a laceration of the skin and soft tissues overlying the mandible as a result of the trauma, it can be employed to gain access to the fracture site. CONTRA-INDICATIONS (i) Delay in treatment. Particularly cases compound into the mouth, and with large haematomata. (2) Grossly comminuted fractures where extent of damage would necessitate use of a plate too long and bulky. (3) Cases where the outer cortical plate is fractured very obliquely resulting in too thin a portion of mandible for retention of screws. (The horizontally unfavourable, vertically unfavourable fracture.) OPERATIVE TECHNIQUE Teeth in the line of fracture, if carious or loosened, are better extracted. I agree with Plumpton and Crawford (1955) that accurate reduction obtained by

4 PLATING OF MANDIBULAR FRACTURES open operation obliterates the dead space between the bone ends and their immobilisation prevents dispersal of the haematoma which seals the tooth socket. But in young people, unless the pulp is exposed or root fractured, we usually retain these teeth, particularly if they are in the incisor region. Access to the fracture site is gained through a skin laceration if present, or via a submandibular incision, 5 cm. in length, one finger's breadth below the lower border. This ensures adequate soft-tissue cover of the plate at the end of the operation. Care is taken to avoid damage to the mandibular branch of the 7th nerve, but any damage sustained is transient, due to plexus formation between the peripheral branches of the 7th nerve which permits regeneration. It must be borne in mind, however, that the more anterior the incision the fewer the communicating branches of this plexus, and if both the mandibular branch of the 7th nerve and the anterior cutaneous branches of C2 and 3 are severed, there is a possibility of permanent paresis resulting to half the lower lip. After reduction has been cffected, a plate of suitable length is placed across the fracture line, ensuring that the screw holes are placed on sound bone. (It is preferable to use the smallest plates and screws possible.) Efforts should be made to place the plate beneath the inferior dental canal and in some cases it is necessary to place it on the lower border of the mandible. Edentulous cases of good depth can be plated above the canal and this is particularly easy via an intra-oral approach. Using the drill for the 6 mm. screws, it is important first to place the two outer screws in position. This permits adjustments to be made in the plane of occlusion. Once these have been made, the inner screws are inserted and all four tightened. If stripping of the thread is encountered on the 6-ram. screw, the design of the screw hole in the plate is such that it permits the use of a 7-ram. screw. The soft tissues are closed with fine catgut, the skin sutures usually without drainage, but in those cases where a haematoma is present, a Zimmer Redivac continuous suction drain is advisable for 24 to 48 hours. Upon completion of the plating procedure, which may in some cases be bilateral, the mouth is examined and toilet and suture performed when necessary. P0st-operatively, the patient is permitted immediate mandibular movement, but if teeth are present correction of any degree of malocclusion by selective grinding is advisable. I97 RESULTS During the ten-year period from I953 to I963, over 350 fractures of the mandible have been treated by open reduction and plating at the Nottingham General and Cky Hospitals, without additional intermaxillary fixation. Sixty cases treated over a two-year period have recently been reviewed. Half were caused by road accident. The remainder by assaults, mining and sporting accidents. The patients' ages ranged from I6 to 6I years. Forty-two of the patients were male. One hundred per cent. of the cases achieved bony union, with full range of mandibular movement and restoration of the occlusion. Although some patients had transient 7th nerve involvement to the lower lip, only one had permanent

5 198 BRITISH JOURNAL OF ORAL SURGERY weakness. Twenty-four patients out of the 60 reviewed had persisting paraesthesia of the lower lip. This figure is very similar to that in Ditchfield's review (196o) of inter-osseous wiring, where, of the 5 patients seen, 22 had paraesthesia of all or half of the lower lip after one year, attributed to the initial injury. 39 patients had single fractures z5 involving the body z2 involving the angle zz involving the symphysis zz patients had double fractures 3 bilateral fractures of the body 9 involving body and condyle 3 involving body and angle 6 involving symphysis and condyle The majority of incision scars were satisfactory. Six patients had bad scars. Of these, four declined revision. One, an African, developed keloid. COMPLICATIONS Six of our patients developed a discharge of pus through the skin incision post-operatively. One case was confirmed as actinomycosis and it is interesting to note that an unerupted wisdom tooth in the line of fraction had been left in situ (Fig. 3). There was evidence of it communicating with k the mouth. The infection was controlled by drainage and a prolonged course of tetracyclin. Healing and union proceeded uneventfully and the wisdom tooth is still in situ, likewise the plate. In retrospect, this tooth would probably have been better extracted at the time of the initial reduction. Three cases on penicillin became infected with Staph. aureus found to be a penicillinase producer. They were all compound into the mouth. Following drainage and treatment FIG. 3 with tetracyclin, the cases cleared Plating of such a fracture without removal of tooth in line of fracture, invites infection. up satisfactorily. In one case, a Streptococcal infection developed which yielded to drainage, irrigation with polybactrin and systemic anti- biotics. It was thought to be a case of cross-infection in a ward, where at the time there were some filthy burns being treated by the open method. In one case it was necessary to remove a plate due to persistent drainage two months after plating. All four screws were found to be loose and bone adjacent to

6 PLATING OF MANDIBULAR FRACTURES 199 the holes, necrotic, but union had taken place satisfactorily. The predominant organism cultured from this wound was alphahaemolytic streptococcus. OTHER USES OF PLATES Encountered by our experience with the plating of fractured mandibles, we have put Vitallium plates to other uses. Ostectomies in the body of the mandible may be plated and the patient permitted immediate mandibular movement (Fig. 4). It is wise to fit a silver cap splint on the lower teeth if present, for additional post-operative support, to counter any malocclusion disturbing callus formation. If the ostectomy is performed in the premolar region (Fig. 5) then access can be made via an intra-oral FIG. 4 Plate employed for bilateral mandibular ostectomy at the angle. FIG. 5 Plate employed for bilateral mandibular ostectomy/osteotomy in premolar region. bucket handle incision, thus eliminating a scar, and the mental nerve can be dissected out more easily from the canal if it is to be preserved. Ostectomies performed at the angle are reached through a submandibular approach. Also osteotomies in the ascending rami. In all instances, Vitallium plates are inserted and the patients permitted immediate mandibular movement. There is a use for the custom-built Vitallium plates to support fragments between which a block or cancellous chip graft has been inserted. Provided good bone can be found for insertion of the screws, the graft will 'take' without further jaw immobilisation (Fig. 6). Finally, in those cases where a hemi-mandibulectomy has been performed and replacement by means of a prosthesis is indicated, the attachment of the pros-

7 200 BRITISH JOURNAL OF ORAL SURGERY thesis to healthy bone can be accomplished by means of a Vitallium plate held in position by screws or nut and bolt (Fig. 7). FIG. 6 A and B, Custom-built plate employed to bridge gap in horizontal ramus at the time of insertion of bone graft. FIG. 7 Acrylic replacement of resected mandible attached to remaining mandible in symphysis region. CONCLUSIONS Open reduction and fixation by plating is indicated in single and multiple fractures of the mandible. Plates may also be employed for fixation in those cases

8 PLATING OF MANDIBULAR FRACTURES 201 requiring bone grafting and corrective surgery. The method ensures accurate approximation of the bone ends and rapid union. The patient is permitted full mandibular movement in the post-operative stage and is rehabilitated at an early date. ACKNOWLEDGMENTS I am indebted to Mr. Wilfred Roberts of Worcester Royal Infirmary for helpful discussions and modifications to the original metacarpel plates, to Mr. Gardner of the London Splint Company for his readiness to manufacture drills and screwdrivers to my design, to Mr. E. S. McLeod, Clinical Photographer, Nottingham General Hospital, for the illustrations, and to Mrs. Gloria Litchfield for the typescript. REFERENCES DITCHFIELD, A. (1960). Br. J. plast. Surg. I3, 146. GIBSON, T. G. & ALLAN, I. MCD. (1956). Br. J. plast. Surg. 2, 117. HAYTON-WILLIAMS, D. S. (1958). Br. ft. plast. Surg. 4, 378. PLUMI'TON, S. & CRAWFORD, B. S. (1955). Br. J. plast. Surg. 2, 165. RANK, B. K., WAKEFIELD, A. R. & GUNTER, G. S. (I955). Br. J. plast. Surg. 3, 279. ROBERTS, W. R. (1964). Br. J. oral Surg., I, 2oo. THOMA, K. H. (1963). Oral Surgery, 4th ed. London: Keimpton. WARD, T. G. (1963). Int. dent. J. 3, 413.