Integration of Trackerless Surface Reconstruction-Based Surgical Navigation With Exoscopic Trans-Mastoid Surgery.

Abstract

A trackerless approach to surgical navigation employing simultaneous localization and mapping (SLAM) algorithms based on surface reconstruction from 3D endoscopy fused with preoperative imaging has been demonstrated to have approximately 1 mm mean surgical navigation errors in the anterior and lateral skull base. This study evaluates the feasibility of a SLAM-based surgical navigation system during combined exoscopic-endoscopic trans-mastoid surgery. Interventional deceased donor cohort study. Tertiary care hospital. Trans-mastoid exoscopic dissections were performed in deceased donor temporal bones. At two operative steps, surface models were reconstructed from stereoscopic exoscopy or endoscopy video, and volumetric computed tomography (CT) models were segmented to generate anatomic models. The surface reconstructions and CT-generated models were coregistered using corresponding features, and accuracy was quantified using four metrics: reconstruction, registration, and exoscope-exoscope or endoscope-exoscope surface-surface (S-S) registration errors. High-fidelity exoscopic surface model reconstruction with coregistration to CT or endoscope surface models was performed after mastoid bone exposure and mastoidectomy in 10 deceased donor temporal bones. The mean (SD) reconstruction, registration, exoscope-exoscope S-S registration, and endoscope-exoscope S-S registration errors in millimeters, respectively, were 0.72 (0.32), 1.43 (0.49), 1.72 (0.59), and 1.49 (0.61). A SLAM-based surgical navigation system can enable accurate localization of anatomic points of interest, which is maintained throughout exoscopic surgical dissection and between alternating use of exoscopy and endoscopy. With further development, this approach to navigation has the potential to provide accurate and continuous navigation data during lateral skull base surgery without compromising surgical efficiency and economy of motion.