The Use of Augmented Reality to Improve Safety of Anterior Petrosectomy: Two-Dimensional Operative Video.

An anterior petrosectomy (AP) provides access to the upper petroclival region, but approach-related complications include seizures and temporal lobe hematomas. Moreover, the floor of the middle fossa contains multiple critical neurovascular structures, and drilling Kawase's quadrilateral must be performed carefully to avoid iatrogenic injury. In particular, the cochlea, carotid artery, and the contents of the internal acoustic canal are vulnerable because there are no locational cues to help the surgeon define their borders. In this video, we demonstrate the use of an augmented reality (AR) to protect critical structures during drilling of an AP. The illustrative case involves a 70-year-old woman with difficulty walking caused by a petrotentorial meningioma. The 3-dimensional, virtual reality rendering (Surgical Theater SRP7.4.0, Cleveland, Ohio, USA) of her patient-specific anatomy was enhanced by "painting" the cochlea, petrous carotid, labyrinthine, and the plane of the internal acoustic canal. This process takes 30-60 minutes, and the resulting rendering was used for surgical rehearsal to optimize the AP for tumor exposure. At surgery, our unique AR technique projects the painted anatomic landmarks into the eye-piece of the navigation-tracked microscope (Surgical Theater Sync AR v.3.8.0). Drilling is performed while the critical structures are visible in AR, superimposed on the patient's anatomy in real-time. The AP in surgery mimicked the one practiced during rehearsal and provided exposure to our patient's tumor. After surgery, the patient awoke without injury to her hearing, balance, or facial movements. By providing visual locational cues to the surgeon, we believe that AR improves the safety to the critical neurovascular structures during AP.