Sagittal Split Ramus Osteotomy Without Segmental Fixation in Skeletal Class II

The new orthognathic treatment strategy of non-segmental fixation (non-fix) sagittal split ramus osteotomy (SSRO) with jaw exercise initiation on the second postoperative day, the so-called physiological positioning strategy (PPS), induces good skeletal stability with few temporomandibular joint (TMJ) symptoms after surgery in skeletal class III. This study aimed to clarify whether non-fix SSRO with modified PPS can be applied to skeletal class II. This retrospective study included skeletal class II patients who underwent non-fix SSRO to correct mandibular retrognathia. Jaw exercise was initiated within 10 postoperative days. Cephalometric analyses were performed before (T1), immediately after (T2), and more than 6 months after (T3) surgery. Skeletal and dental stability, and TMJ symptoms were evaluated. Twelve patients (2 men, 10 women; mean age 22.9±7.1 y) were included. The mean mandibular advancement was 6.8±1.8 mm. angle between S-N and N-B. was 73.6±4.5, 77.1±3.9, and 75.1±4.4 degrees at T1, T2, and T3, meaning 60.5% relapse. The Menton moved forward by 6.3 mm from T1 to T2 and relapsed by 4.6 mm at T3. The duration of intermaxillary traction showed a moderate negative correlation with angle between S-N and N-B. relapse (r=-0.42, P =0.1787). Only 2 TMJ symptoms (2/24, 8.3%) developed postoperatively. This study suggests that non-fix SSRO with modified PPS is a suitable method for skeletal class II malocclusion. Further research with a larger sample size and detailed analysis of the effect of intermaxillary traction on skeletal stability after surgery is needed.