비대칭 하악전돌증 환자에서의 구내 하악골 상행지 수직 골절단술(IVRO) 시행후 우각부 비대칭 개선의 평가

Evaluation of gonial angle asymmetry after IVRO in facial asymmetry with mandibular prognathism

We treated 14 cases of facial asymmetry with mandibular prognathism from January 1993 to December 1994. In deviation prognathism cases, bilateral IVRO was performed in 11 patients, and 3 patients recevied SSRO on one side and IVRO on the contralateral side. Difference between Rt. gonial angle and Lt. gonial angle measurement from the midsagittal plane was calculated on Cephalograms and facial photos. Furthermore changes between preoperative and postoperative were evaluated three months later. The following results were obtained. 1. The patients with deviation prognathism who were opertated by bilateral IVRO can be classified as cases with unilateral overlapping and bilateral overlapping between osteotomized bony segments. 2. There are two kinds of deviation prognathism. One kind is composed of patients who had bulky angle on the ipsilateral side of chin devation, and the other kind is composed of patients who had bulky angle on the contralateral side of chin deviation. 3. In case of the overlapping between the osteotomized bony segments, more bulky angle is induced. 4. In bilateral IVRO cases, the side which has larger amount of setback shows less increase of prominence in gonial angle area. 5. Because the change of prominence in soft tissue is not proportionate to the change in bone structure, accurate preop. prediction of the soft tissue change on gonial angle area is difficult.