Accuracy of computer-simulated mandibular autorotation following single-jaw maxillary repositioning surgery using customized surgical cutting guides and fixation plates.

Abstract

The literature on computer-aided surgical simulation (CASS) has focused extensively on the precision and accuracy of maxillary and mandibular repositioning surgery. However, the predictability of mandibular autorotation remains understudied. The aim of this study was to evaluate the accuracy of CASS-planned mandibular autorotation in 50 consecutive patients undergoing maxillary repositioning surgery with customized titanium surgical cutting guides and fixation plates. The study patients (32 male and 18 female, mean age 25 years for both sexes) underwent Le Fort I osteotomy, with or without simultaneous genioplasty were performed by one experienced maxillofacial surgeon. Preoperative and postoperative multi-slice computed tomography scans were superimposed and contrasted with the surgical plan to evaluate any discrepancies between the planned and observed mandibular positions after surgery. The translational movements of the maxilla were a median 0.38 mm transversely, mean -5.29 mm anteroposteriorly, and median -1.00 mm vertically. Using a computed mandibular centroid, the absolute linear and angular discrepancies between the planned and observed mandibular autorotation movements were found to be within the clinically significant thresholds of 1 mm and 2°, respectively. It is concluded that CASS-planned mandibular autorotation is predictable when maxillary down-grafting and impaction does not exceed 5 mm and 4 mm, respectively.