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.