하악전돌증 환자의 구내 하악골상행지 수직골절단술 후 골편들의 장기 형태개조에 관한 임상적 연구

Abstract

Intraoral vertical ramus osteotomy(IVRO) is one of the most common procedures for surgically correcting mandibular prognathism. It has many advantages such as a safe and easily performed surgical technique, less temporomandibular joint dysfunction and less damage to the inferior alveolar nerve, etc. Its good clinical results and relative stability are also well-documented. In IVRO, bony healing undergoes in a stage of cortex-to-cortex contact, i.e. the proximal segments placed lateral to the distal segment without any fixations. This was different from the traditional bony healing of fractures. Although many studies on the displacement of the mandibular condyle have been reported, long-term evaluations on skeletal remodeling and its amount of the osteotomized segments after IVRO are lacking. The aim of this investigation was to study the radiographic time of a long-term morphologic change and its amount of the osteotomized segments after IVRO in mandibular prognathism, evaluated by panoramic, posterior-anterior cephalometric and lateral cephalometric recordings. Radiographs were taken immediately after surgery, 1 month, 3 months, 6 months and 1 year postoperatively. To study this, radioraphic analysis was done on 21 patients(male 8, female 13) who were diagnosed as having mandibular prognathism and treated with IVRO from October 1992 to September 1993 and followed up over 1 year. the following results were obtained: 1. Between 3 months and 6 months postoperatively, continuity of sigmoid notch and mandibular angle and disappearance of osteotomy line were most frequently observed. 2. There were continuous decrease in vertical length of the proximal segments and horizontal length between proximal segments, Continuous increase of mandibular angle and also disappearance of osteotomy line in overlapping area in all case were observed. 3. There were no significant difference of linear and angular changes according to the timetable between the vertical length of proximal segment and the gap of the proximal and distal segment, horizontal length of proximal segment and mandibular angle. 4. According to results of correlation analysis between corresponding parameters, the vertical change of the proximal segment showed a high positive correlation(r>0.8) until 1year postoperatively and the gap change between the proximal and the distal segments showed a moderated change(0.6>r>0.5) until 3 months postoperatively(p<0.01) and a low positive change(r<0.3) from 3 months to 1 year after surgery. 5. In all 21 cases, there were no complications such as bone necrosis of proximal segments or nonurion between proximal and distal segments From the above results, the following conclusion was obtined. Radiographic skeletal remodeling was mostly observed between 3 months and 6 months after IVRO and this may be due to the positional change of the proximal segment and due to broad dissection of the proximal and distal segment. And also broad dissection of the proximal segment resulted in promoting skeletal remodeling but there was no evidence of complications such as nonunion or necrosis of osteotomized segments. Under the circumstances of early mandibular movement and broad periosteal dissection more detailed study on long-term skeletal remodeling may be needed in the future.