The Sellar Region as Seen from Transcranial and Endonasal Perspectives: Exploring Bony Landmarks Through New Surface Photorealistic Three-Dimensional Model Reconstruction for Neurosurgical Anatomy Training

- BACKGROUND: Virtual realityebased learning of neuroanatomy is a new feasible method to explore, visu- alize, and dissect interactively complex anatomic regions. We provide a new interactive photorealistic three- dimensional (3D) model of sellar region microsurgical anatomy that allows side-by-side views of exocranial and endocranial surfaces to be explored, with the aim of assisting young neurosurgery residents in learning micro- surgical anatomy of this complex region. - METHODS: Four head specimens underwent an endo- scopic endonasal approach extended to the anterior and pos- terior skull base to expose the main bony anatomic landmarks of the sellar region. The same bony structures were exposed from a transcranial perspective. By using a photogrammetry method, multiple photographs from both endocranial and exocranial perspectives, different for angulations and depth, were captured, fused, and processed through dedicated software. - RESULTS: All relevant bony structures were clearly distinguishable in the 3D model reconstruction, which pro- vides several benefits in neuroanatomy learning: first, it replicates bony structures with high degrees of realism, ac- curacy, and fidelity; in addition, it provides realistic spatial perception of the depth of the visualized structures and their anatomic relationships; again, the 3D model is interactive and allows a 360 self-guided tour of the reconstructed object, so that the learner can read the bones and their anatomic relationship from all desired points of view. - CONCLUSIONS: Detailed knowledge of key surgical landmarks representing keyholes and/or anatomic struc- tures to not violate is mandatory for safer surgery, especially for a complex region such as the skull base. Highly accurate virtual and functional neurosurgical models, such as photogrammetry, can generate a realistic appearance to further improve surgical simulators and learn neuroanatomy.