PURPOSE: Of the procedures that make up facial feminization surgery, frontal sinus setback has a particularly high impact on gender perception. Mixed reality (MR) is a nascent technology that holds significant promise in plastic and reconstructive surgery. MR allows a user to view and manipulate three-dimensional patient images while superimposing them on the patient. This method allows for direct visualization of deep structures, improving a surgeons understanding of vital patient anatomy in real time. To the best of our knowledge, this is the first usage and evaluation of this technology inside of a plastic surgery operating room in the United States.
METHODS: The Medivis SurgicalAR system was used in conjunction with the Microsoft HoloLens, an MR headset with a see-through visor. CT imaging was uploaded to the SurgicalAR system and a three-dimensional hologram was projected onto the display of the HoloLens. The CT was registered to the patient using a point-to-point framework that relied on bony fiducials identified intra-operatively, namely the supraorbital notches, nasion, and glabella, matched to virtual counterparts. The system relies on a localizing wand with an affixed optical code that the 2D RGB camera on the headset tracks. Time measures and discrepancy from our standard-of-care 3D cutting guide were measured along with survey of the operating surgeon.
RESULTS: Qualitative descriptions demonstrated that 3-dimensional visualization of deep structures improved surgeon confidence and operative decision making. The process of matching the hologram to the patient and cropping to see intended structures took three minutes and twelve seconds. Tracing of the frontal sinuses based on the hologram took 61 seconds. Maximum discrepancy from the 3D cutting guide was 5mm and minimum was exactly the same. In addition, the workflow that was established was both efficient and intuitive.
CONCLUSION: Mixed reality was shown to be accurate in superimposing a patient’s CT on top of their actual skull during surgery, allowing for a tracing of the frontal sinuses. This rapidly developing technology demonstrates promise for being a viable intraoperative image guidance technology and may provide a faster and more effective method of anatomical identification than the current standard of care.