Application of mixed reality bone registration and positioning technology in orthognathic surgery.

In orthognathic surgery, the positioning of the bone segments has a significant impact on the postoperative occlusion, temporomandibular joint, and facial morphology. Within the field of digital surgical planning, the placement of these bone segments represents the transfer of the virtual surgical plan (VSP). Computer-aided design/computer-aided manufacturing-assisted bone segment positioning devices have demonstrated high localization accuracy, but they require complex guide systems. The mixed reality technique described here, based on pre-bent titanium plates, facilitates the transfer of the VSP without the need for complex guide systems and enables dynamic intraoperative navigation under direct vision. This technique could replace 3D-printed tooth-supported guide plates for surgical navigation. The observed registration error was approximately 1 mm and the registration delay was 0.3 s. Application of this technique in the clinical case demonstrated good accuracy, and postoperative stability was achieved.