Mixed Reality in the Operating Room: An Initial Use in Frontal Sinus Setback in Gender-affirming Facial Surgery.

Demand for gender-affirming facial surgery is growing rapidly. Frontal sinus setback, one of the key procedures used in gender-affirming facial surgery, has a particularly high impact on gender perception. Mixed reality (MR) allows a user to view and virtually overlay three-dimensional imaging on the patient and interact with it in real time. We used the Medivis's SurgicalAR system in conjunction with the Microsoft HoloLens Lucille2 (Microsoft). Computed tomography imaging was uploaded to SurgicalAR, and a three-dimensional (3D) hologram was projected onto the display of the HoloLens. The hologram was registered and matched to the patient, allowing the surgeon to view bony anatomy and underlying structures in real time on the patient. The surgeon was able to outline the patient's frontal sinuses using the hologram as guidance. A 3D printed cutting guide was used for comparison. Negligible difference between the mixed reality-based outline and 3D-printed outline was seen. The process of loading the hologram and marking the frontal sinus outline lasted less than 10 minutes. The workflow and usage described here demonstrate significant promise for the use of mixed reality as imaging and surgical guidance technology in gender-affirming facial surgery.