Computer-aided Surgical Planning and Osteosynthesis Plates for Bimaxillary Orthognathic Surgery: A Study of 14...

Computer-aided surgical planning has become popular for planning orthognathic surgery (OS) as it saves surgeons' time and effort. A recent advancement has been the utilization of patient-specific cutting guides and osteosynthesis. The purpose of this study is to report the postoperative bimaxillary position utilizing custom plates for both jaws versus custom plates used in the maxilla only in 23 consecutive patients.

All patients who underwent bimaxillary OS in 2017-2018 with preoperative computed tomography (CT) scan, postoperative day 1 CT scan, and at least 6 months follow-up were included in the study. Group 1 utilized maxillary preprinted plates (maxilla only). Group 2 utilized bimaxillary preprinted plates (maxillomandibular). Eight cephalometric landmarks to evaluate the movements were chosen. The ranges of the angle between the sella/nasion plane and the nasion/A plane (SNA), the angle between the sella/nasion plane and the nasion/B plane (SNB), and the angle created by the A point' nasion' and B point' which measures the relative position of maxilla to mandible, were analyzed to assess the angular change. Mean-squared displacement and the SD of the distances were used to assess movement in space.

Twenty-three patients (nine in group 1 and 14 in group 2) met the inclusion criteria. Results showed interarch relationships using custom plates for both jaws with ANB 0.4 compared to ANB 1.4 for maxillary custom plates only. Mandibular landmarks showed greater variation, and the t test study revealed the right mandibular first molar landmark showing the greatest variation (P = 0.03).

Custom osteosynthesis plates for OS show good accuracy for the maxilla and higher variation in the mandible. Further studies will determine the margin of error that cannot be corrected with postoperative orthodontics.