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Multiportal Robotic Access to the Anterior Cranial Fossa: An Engineering and Surgical Feasibility Study

Objectives: Use of robotic surgical technology in skull base surgery has been limited due to the need for 3 non-disruptive surgical portals; adequate working space between the large robotic arms; and the steep approach angle to the skull base. The objectives were to determine the minimum space requirements between robotic arms, systematically analyze surgical approach portals in a computer model, and assess task performance capability of the derived approaches. Methods: A computer analysis on 10 computed tomography scans computed approach trajectory angles and distances to specified skull base target locations for multiportal surgical approaches. The optimal combinations of portals were tested using the da Vinci and Raven robotic systems to perform tasks, both in dry lab and cadaver settings. Results: Two robotic tools required an angle of at least 20 degrees between them to function effectively at the skull base targets. In the computer analysis, the angle between two transnasal robotic tools was 14.7, and combining with transorbital portals yielded angles much larger (up to 46.0 degrees). Additionally, the skull base trajectory angle was improved by greater than 28 degrees. Conclusions: Computer analysis and cadaver testing demonstrated that the optimal multiportal combination to access sella and parasellar target locations was using 1 transnasal and 2 transorbital portals. This technique addresses the 2 major challenges of 1) the narrow funnel effect generated from portals in close proximity and 2) the steep angle of approach to the skull base, reported in studies evaluating transoral, transcervical, transmaxillary, and transhyoid portals.