SURGICAL TREATMENT OF MANDIBULAR ASYMMETRY By MARIAN GORSKI, M.D., 1 and IRENA HALINA TARCZYNSKA, M.D. Maxillo-Facial Clinic, Warsaw Medical Academy

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1 SURGICL TRETMENT OF MNDIULR SYMMETRY y MRIN GORSKI, M.D., 1 and IREN HLIN TRCZYNSK, M.D. Maxillo-Facial Clinic, Warsaw Medical cademy UNILTERL mandibular deformities may be due to either overgrowth or underdevelopment of part of the mandible. The whole half-mandible or only its ramus, body, or even the condyloid process alone may be affected. Usually underdevelopment affects the entire half of the mandible without any apparent cause and the patient or his relatives first become aware of it around puberty. The deformity may accompany malformations of the ear and pinna, seventh nerve paresis and other anomalies belonging to first and second branchial arch syndromes (Dingman and Grabb, 1963). In addition to congenital deformities, acquired facial asymmetry may be due to unilateral sequestration in mandibular osteitis or damage to the cartilaginous growth centre in the condyle due to an inflammatory process or trauma, a condition often accompanied by ankylosis of the joint. When the deformity is due to underdevelopment of part of the mandible the condition may be described as hemimicrognathia. The affected side of the mandible is shorter than the normal and the chin with the central point of the mandible is displaced towards the affected side. The mandibular body may be also considerably shortened and the chin displaced backwards. The mandibular ramus is shorter than that on the normal side. In unilateral mandibular overgrowth reverse conditions are found. The chin is displaced towards the normal, non-affected side and the mandibular body is larger than that of the normal side. This has been defined as" unilateral prognathism " (Plumpton, 1967). Overgrowth of the condyle only, with asymmetry of the mandible, was described by Thoma (195o). Clinical Material.--Six patients with unilateral asymmetrical mandibular deformities have been treated. Three had unilateral prognathism of unknown but presumably congenital origin, two had unilateral underdevelopment due to osteitis and one had hemimicrognathia associated with a temporo-mandibular ankylosis. Teclmique.mTreatment consisted in bilateral osteotomy of the mandibular rami. On the sound side a vertical osteotomy posterior to the mandibular foramen was performed ; on the abnormal side, on the other hand, the osteotomy was horizontal above the foramen. The mandibular body thus mobilised could be shifted in the required direction so that proper occlusion could be established, or at least made as near to normal as possible. In cases of overgrowth, the mandibular body was shifted towards the abnormal side where overlapping of the divided halves of the ramus indicated how much bone had to be excised to reduce the length of the ramus to a normal size. When the excess bone was resected the fragments were fixed together with a wire suture. In cases of underdevelopment, the mandibular body had to be shifted to the sound side so establishing a bone defect of the ramus which was filled with spongy bone chips from the iliac crest. Intermaxillary fixation was applied in all cases for four weeks. 1 Professor, chief of Clinic. 370

2 SURGICL TRETMENT OF MNDIULR SYMMETRY 371 CSE REPORTS Case I.--(Fig. I, and ).--The patient, aged 3 I, had a marked facial deformity due to overgrowth of the right half of the mandible involving both length and width of the body and the ramus. The chin was pushed forward and towards the sound side and there was no occlusion on the abnormal side and anteriorly. The patient first noticed her deformity when she was aged x3. fter bilateral osteotomy of the rami as described above, the excessively long ramus was shortened and the mandibular body placed in position, in harmony with the facial outline and with normal occlusion. FIG. I Case i.--facial asymmetry caused by overgrowth of the right mandibular ramus and body., efore operation., Post-operative result. Case 2.~(Fig. 2,,, C and D).--The facial deformity in this man of 3I was the result of overgrowth of the right half of the mandible in all dimensions, displacing the chin towards the sound side. The surgical treatment was similar to that described in Case I. Case 3.re(Fig. 3,,, C and D).mThe deformity in this girl of x 7 was similar to that in Case 2. In addition to a vertical osteotomy of the ramus on the abnormal side, a vertical osteotomy of the body at the junction of the normal and deformed segments was performed. Case 4.--(Fig. 4,,, C and D).--This boy, now aged 14, suffered from mandibular osteitis with sequestration in his early childhood. The mandibular body was short and displaced to the right with irregular occlusion. Surgical treatment consisted, as before, in vertical osteotomy of the mandibular ramus on the sound side and horizontal osteotomy of the right ramus. The mobilised mandibular body was shifted forward and to the left, thereby achieving better occlusion. bone defect on the right was filled with bone chips from the iliac crest (Gorski, I958). Case 5.--(Fig. 5, and ).--The patient, aged I6, had a similar deformity to Case 4 and the surgical treatment was essentially the same.

3 372 RITISH JOURNL OF PLSTIC SURGERY C FIG. 2 Case 2.--Facial asymmetry due to overgrowth of mandibular ramus and body~ right side., efore operation. e Post-operative result. C~ Pre-operative X-ray. D, Post-operative X-ray. D

4 SURGICL TRETMENT OF MNDIULR SYMMETRY 373 C D FIG. 3 Case 3. Facial asymmetry caused by right mandibular hypertrophy., Pre-operatlve appearance., Post-operative result ; in addition to a vertical osteotomy of the left ramus, a segment of the left mandibular body including two teeth was excised. C and D, rticulation before and after operation. 4F

5 374 RITISH JOURNL OF PLSTIC SURGERY C D Fro. 4 Case 4.--Facial asymmetry due to underdevelopment of the right mandibular body following osteitis in childhood., Pre-operative appearance., Post-operative result. C and D, Pre- and post-operative occlusion. Case 6.--(Fig. 6, to 6).raThe patient, aged 24, was admitted because of a right temporomandibular ankylosis with considerable facial deformity ; the mandible was pushed backwards, the chin displaced to the right side and the mandibular ramus and symphysis shortened on the right side. horizontal osteotorny was performed below the ankylosed joint, the defect being enlarged to provide good mobility, and a vertical osteotomy on the sound ramus. Intermaxillary fixation for four weeks did not affect the mobility of the new articulation. The surgical treatments described were supplemented when necessary by small corrective operations, such as trimming the mandibular border in unilateral prognathism or adding bone chips in order to augment the flattened segment of the underdeveloped mandible.

6 SURGICL TRETMENT OF MNDIULR SYMMETRY 375 FIG. 5 Case 5.---Facial asymmetry caused by underdevelopment of the right mandibular body., Pre-olberative appearance., Post-operative result. DISCUSSION Ramon and uchner (I965) advise condylectomy for surgical treatment of unilateral mandibular overgrowth. Other authors recommend bilateral subcondyloid osteotomy (Reid, Hinds and Mohnac, 1966) or operations on the mandibular body (Dingman and Grabb, 1963 ; Plumpton, 1967) The method here presented is simpler and since the osteotomy involves the mandibular ramus and not the body, infection of the bone wounds and bone grafts with saliva is avoided. The horizontal osteotomy on the abnormal side allows the surgeon to shorten the overgrown ramus by excising the excess bone, or to lengthen the underdeveloped ramus by inserting a bone graft. The vertical osteotomy on the sound side completes the mobilisation of the body by allowing the ramus to rotate around its vertical axis without change in shape and without leaving any gap. The vertical osteotomy also compares favourably with subcondylar osteotomy, since the difficulty of controlling the smaller fragment is avoided. s in Case 3, the technique described may also be combined with an excision of bone from the body, particularly when this is required to produce good occlusion. In Case 6 the technique was combined with mobilisation of the ankylosed temporomandibular joint. SUMMRY I. In most cases mandibular asymmetry may be corrected by a vertical osteotomy of the normal ramus combined with a horizontal section of the ramus on the affected side.

7 376 RITISH JOURNL OF PLSTIC SURGERY C D E F FIG. 6 Case 6.--Facial asymmetry due to right temporo-mandibular ankylosis., Pre-operative appearance., Post-operative result. C, Profile before operation. D, Profile after operation. E and F~ Pre- and post-operative occlusion.

8 SURGICL TRETMENT OF MNDIULR SYMMETRY 377 FIG. 6, G Mobility of the mandible. 2. In cases of asymmetry due to unilateral overgrowth, the excessive length of the affected ramus may be reduced by excising bone at the site of the horizontal osteotomy. 3. Conversely, if the deformity is due to unilateral underdevelopment, bone chips may be added to the horizontal osteotomy to increase length. 4. In a case of underdevelopment accompanied by ankylosis, the joint was successfully mobilised by widening the defect at the site of the horizontal osteotomy. REFERENCES DINGMN, R. O. and GR, W. C. (I963). Plastic reconstr. Surg. 6, 563. GoRsKI, M. (r958). nnls Chit. plast. 6, I43. PLUraPTON, S. (I967). r. J. plast. Surg. I, 7 o. RMON, Y. and UCHNER,. (I965). r. J. plast. Surg. 4, 428. RID, R., HINDS, E. C, and MOHNC,. M. (I966). J. oral Surg. 5, 527 THOM, K. H. (r95o). "Oral Pathology." St Louis : Mosby.