Application of digital planning in goniolpasty

Abstract

Objective To design the aesthetic new gonion and osteotomy line for patients with prominent mandibular angle patients using computer-aided techniques, and to investigate the application of three-dimensional digital planning in gonioplasty. Methods From April 2016 to April 2017, 14 female patients with prominent mandibular angle underwent preoperative surgical design and surgical simulation using digital technology. Gonioplasty was performed under the guide of surgical templates, preoperative, surgical simulation and postoperative data were measured including bilateral mandibular angles, the height of ramus(Co-Go) and the length of mandibular body(Go-Me). Paired t test was used to compare the differences between surgical simulation and postoperative measurements. Results Gonioplasty was performed in 14 patients successfully, and all were satisfied with their facial outcomes. The mandibular angle was improved from 113.86°±4.11° to 124.52°±1.26° on the left side, and 114.30°±4.01° to 124.29°±1.24° on the right side respectively. The average ratio of Go-Me/Co-Go was 2.011 on both sides after operation, which was very close to surgical planning. No significant differences were found between surgical planning and postoperative measurements with respect to mandibular angle or the ratio of Go-Me/Co-Go on both sides(P>0.05). The deviations between them were 1.00°±0.68° and 0.058±0.038 on the left side, and 0.85°±0.63° and 0.072±0.053 on the right side respectively. Conclusions Computer-assisted gonioplasty could improve the efficiency and accuracy of surgery, reduce the risk of surgical complications, and attain higher patients′ satisfaction. Key words: Three-dimensional digitization; Prominent mandibular angle; Gonioplast; Surgical template