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Correction of unilateral mandibular prognathism by ostectomy of the mandibular symphysis combined with anterior alveolar surgery
British Journal of Plastic Surgery (x976), 29, 38-40
C O R R E C T I O N OF U N I L A T E R A L M A N D I B U L A R P R O G N A T H I S M BY O S T E C T O M Y OF T H E M A N D I B U L A R S Y M P H Y S I S C O M B I N E D WITH A N T E R I O R A L V E O L A R S U R G E R Y By DERYCK J. EGGLESTON,M.B.B.S., F.D.S.R.C.S., F.R.A.C.D.S.
Royal Perth Hospital, Perth, Western Australia UNILATERAL mandibular prognathism may be caused by excess growth o f the condyle on the affected side or by unilateral macrognathia in which all the osseous elements o f one side of the jaw are enlarged. In the latter the body o f the mandible on the affected side becomes longer, the symphysis shifts across the midline and a unilateral cross bite develops on the normal side o f the jaw (Rowe, 196o). T h e operation ofsymphyseal mandibular ostectomy combined with anterior alveolar ostectomy was first described by Sowray and Haskell (1968) for mild prognathism with severe cross bite. O'Driscoll (1971) has also used it in a case of maxillary hypoplasia with mandibular prognathism where it was inadvisable to alter the maxilla. It may also be successfully used to correct unilateral mandibular prognathism. CASE REPORT A I6-year-old fit young man had a large chin which was obviously deviated to the left (Fig. I). There was an inferior protrusion with a reverse overjet on the left and the midline between the lower incisors was transposed to the left. The right posterior occlusion was normal but on the left there was a cross bite (Fig. 2). The first molars on each side were missing and drifting of the premolar teeth had created spaces on both sides of the arch. X-ray confirmed elongation of the right body of the mandible. It became apparent from study models that it would not be possible to obtain a satisfactory occlusion by rotating and setting back the intact mandible. However a symphyseal ostectomy and alveolar surgery could produce a satisfactory correction of the midline incisal shift. The left posterior cross bite could also be corrected while maintaining the right posterior occlusion in a normal relationship. A premolar on the right side of the arch had to be sacrificed (Fig. 3)Preoperatively a cap splint was constructed for the lower anterior teeth. Arch bars were cast for the posterior teeth and these could be screwed to the cap splint by means of locking plates, only after the final occlusion on each side had been established. The 4/was extracted. At operation a cast arch bar was wired to the maxillary teeth and the cap splint cemented to the lower anteriors. On completion of the alveolar ostectomy the lower anterior teeth and bone were shifted posteriorly and to the right to correct the incisal midline discrepancy. The right side arch bar was locked onto the cap splint and the bar wired to the posterior teeth. Intermaxillary fixation (I.M.F.) was temporarily applied fixing the right posterior occlusion until the symphyseal ostectomy had been completed. The left posterior occlusion was then swung medially into a normal relationship with the maxillary teeth and the left locking plate with arch bar fitted to the teeth and screwed to the cap splint. The I.M.F. was released until the end of the operation. The excess bone on the right side of the symphyseal cut was removed and some contouring of the bone was necessary in the canine region at the left lower border to achieve symmetry. Cancellous bone was packed around the ostectomy sites and a wire inserted across the symphyseal bone ends. Postoperatively the I.M.F. was released at 13 days, and the patient bit easily into the correction position. After 4 weeks the cap splint and arch bar were removed and good union 38
CORRECTION OF UNILATERAL MANDIBULAR PROGNATHISM
FIG. I. FIG. 2.
®
39
Preoperative. Large chin deviated to the left.
Preoperative occlusion shows inferior protrusion, reverse overjet on the left and midline displaced to the left.
i_.._.-J FIG. 3. The planned ostectomies and alveolar segmental shift. FIG. 4. Postoperative occlusion.
was noted at the ostectomy sites. At 6 months the satisfactory postoperative position appears stable (Fig. 4). DISCUSSION
In unilateral mandibular deformities this combined operation is particularly useful. One side of the posterior occlusion can be fixed in relation to the maxilla and the other moved to a desired position. The correction of a co-existing anterior abnormality is
4°
BRITISH JOURNAL OF PLASTIC SURGERY
FIG. 5- Six months postoperatively facial symmetry has been achieved.
readily achieved using alveolar segmental surgery. In the case described the left posterior occlusion was moved medially and the left condyle rotated in the glenoid fossa. The rotation appears to have been well tolerated, and 6 months after the operation there are no clinical signs or symptoms of joint dysfunction (Fig. 5). REFERENCES O'DRISCOLL, P. (1970). Ostectomy at the midline of the mandible. British Journal of Plastic Surgery, 24, 7I: RowE, N.L.(I96O). The aetiology, clinical features and treatment of mandibular deformities. British DentalJournal, lO8, 45. SOWRAY, J. and HASKELL, R. (I968). Ostectomy at the mandibular symphysis. British
Journal of Oral Surgery, 6, 97.
C O R R E C T I O N OF U N I L A T E R A L M A N D I B U L A R P R O G N A T H I S M BY O S T E C T O M Y OF T H E M A N D I B U L A R S Y M P H Y S I S C O M B I N E D WITH A N T E R I O R A L V E O L A R S U R G E R Y By DERYCK J. EGGLESTON,M.B.B.S., F.D.S.R.C.S., F.R.A.C.D.S.
Royal Perth Hospital, Perth, Western Australia UNILATERAL mandibular prognathism may be caused by excess growth o f the condyle on the affected side or by unilateral macrognathia in which all the osseous elements o f one side of the jaw are enlarged. In the latter the body o f the mandible on the affected side becomes longer, the symphysis shifts across the midline and a unilateral cross bite develops on the normal side o f the jaw (Rowe, 196o). T h e operation ofsymphyseal mandibular ostectomy combined with anterior alveolar ostectomy was first described by Sowray and Haskell (1968) for mild prognathism with severe cross bite. O'Driscoll (1971) has also used it in a case of maxillary hypoplasia with mandibular prognathism where it was inadvisable to alter the maxilla. It may also be successfully used to correct unilateral mandibular prognathism. CASE REPORT A I6-year-old fit young man had a large chin which was obviously deviated to the left (Fig. I). There was an inferior protrusion with a reverse overjet on the left and the midline between the lower incisors was transposed to the left. The right posterior occlusion was normal but on the left there was a cross bite (Fig. 2). The first molars on each side were missing and drifting of the premolar teeth had created spaces on both sides of the arch. X-ray confirmed elongation of the right body of the mandible. It became apparent from study models that it would not be possible to obtain a satisfactory occlusion by rotating and setting back the intact mandible. However a symphyseal ostectomy and alveolar surgery could produce a satisfactory correction of the midline incisal shift. The left posterior cross bite could also be corrected while maintaining the right posterior occlusion in a normal relationship. A premolar on the right side of the arch had to be sacrificed (Fig. 3)Preoperatively a cap splint was constructed for the lower anterior teeth. Arch bars were cast for the posterior teeth and these could be screwed to the cap splint by means of locking plates, only after the final occlusion on each side had been established. The 4/was extracted. At operation a cast arch bar was wired to the maxillary teeth and the cap splint cemented to the lower anteriors. On completion of the alveolar ostectomy the lower anterior teeth and bone were shifted posteriorly and to the right to correct the incisal midline discrepancy. The right side arch bar was locked onto the cap splint and the bar wired to the posterior teeth. Intermaxillary fixation (I.M.F.) was temporarily applied fixing the right posterior occlusion until the symphyseal ostectomy had been completed. The left posterior occlusion was then swung medially into a normal relationship with the maxillary teeth and the left locking plate with arch bar fitted to the teeth and screwed to the cap splint. The I.M.F. was released until the end of the operation. The excess bone on the right side of the symphyseal cut was removed and some contouring of the bone was necessary in the canine region at the left lower border to achieve symmetry. Cancellous bone was packed around the ostectomy sites and a wire inserted across the symphyseal bone ends. Postoperatively the I.M.F. was released at 13 days, and the patient bit easily into the correction position. After 4 weeks the cap splint and arch bar were removed and good union 38
CORRECTION OF UNILATERAL MANDIBULAR PROGNATHISM
FIG. I. FIG. 2.
®
39
Preoperative. Large chin deviated to the left.
Preoperative occlusion shows inferior protrusion, reverse overjet on the left and midline displaced to the left.
i_.._.-J FIG. 3. The planned ostectomies and alveolar segmental shift. FIG. 4. Postoperative occlusion.
was noted at the ostectomy sites. At 6 months the satisfactory postoperative position appears stable (Fig. 4). DISCUSSION
In unilateral mandibular deformities this combined operation is particularly useful. One side of the posterior occlusion can be fixed in relation to the maxilla and the other moved to a desired position. The correction of a co-existing anterior abnormality is
4°
BRITISH JOURNAL OF PLASTIC SURGERY
FIG. 5- Six months postoperatively facial symmetry has been achieved.
readily achieved using alveolar segmental surgery. In the case described the left posterior occlusion was moved medially and the left condyle rotated in the glenoid fossa. The rotation appears to have been well tolerated, and 6 months after the operation there are no clinical signs or symptoms of joint dysfunction (Fig. 5). REFERENCES O'DRISCOLL, P. (1970). Ostectomy at the midline of the mandible. British Journal of Plastic Surgery, 24, 7I: RowE, N.L.(I96O). The aetiology, clinical features and treatment of mandibular deformities. British DentalJournal, lO8, 45. SOWRAY, J. and HASKELL, R. (I968). Ostectomy at the mandibular symphysis. British
Journal of Oral Surgery, 6, 97.