Skull Base Virtual Reality Surgical Simulator Integrating Multilayered 3D Photorealistic Anatomic Models With 3D Imaging and Segmentations: Transpetrosal Approaches

BACKGROUND AND OBJECTIVES: Lesions within the petrous bone pose significant surgical challenges and necessitate a detailed 3-dimensional (3D) understanding of the skull base anatomy. Microsurgical dissections are gold standard to acquire such knowledge in combination with patient-specific anatomy derived from diagnostic imaging. Therefore, we developed a virtual reality (VR)-based surgical simulator that fuses and stacks stepwise, photorealistic 3D models of anatomic dissections and 3D angiographies. We sought to demonstrate how VR-based simulation can improve 3D understanding of the skull base anatomy and the surgical anatomy in tumor resections, using transpetrosal approaches as proof-of-concept, with simulated tumor renderings according to the Fisch classification. METHODS: One body donor head, ethanol-fixed and arterially injected with a red latex-contrast medium mixture, underwent rotational angiography and stepwise microsurgical dissection following trans- (posterior and combined) petrosal approaches. 3D data consisted of Digital Imaging and Communications in Medicine-based 3D angiographic renderings and photogrammetric 3D models showing each step of the approaches. The 3D models were automatically stacked using a 3D modeling software. The resulting 3D data were imported into a VR-environment. Tumor simulations were placed within the virtual 3D space to improve 3D depth understanding of the petrous anatomy during stepwise surgery. RESULTS: Twenty 3D models created by photogrammetry were automatically stacked in VR to simulate transpetrosal and jugular foramen approaches with parallel 3D angiographic data. This allowed for a stepwise visualization of the surgical stages correlated to angiographic anatomy in an immersive environment. Incorporated tumor simulations were useful to mimic pathological anatomy from tumor propagation. CONCLUSION: Automatic alignment of 3D models created by photogrammetry and 3D renderings of diagnostic imaging in a VR environment illustrates the surgical steps of complex transpetrosal approaches. The proposed algorithm to create a surgical simulator is not technically demanding, features a semiautomated workflow, and can be used to present complex surgical approaches that require 3D understanding.