Skull Base Anatomy Presented in 360° Photogrammetry 3-Dimensional Models.

Abstract

Background and objectives: Realistic 3-dimensional (3D) anatomical models may enhance three-dimensional comprehension of the complex anatomy of the skull base. Such models may be generated by photogrammetry, a technical algorithm for photorealistic surface scanning. This study presents a 360° visualization of key neuroanatomical landmarks of the central skull base.

Methods: One formaldehyde-fixed head specimen with polymer-injected vessels underwent extensive exocranial and endocranial dissections on the right side after a sagittal cut. Initially, the dissection of the orbital region, cavernous sinus, and paranasal sinuses identified cranial nerves II, III, IV, and VI; their branches; extraocular muscles; and major vessels. Subsequently, the 5 terminal branches of the VII were exposed, along with cranial nerves IX, X, XI, and XII. A retrolabyrinthine approach and neck dissection revealed the entire course of cranial nerve VII, sigmoid sinus, the jugular bulb, and the intracranial and extracranial segments of nerves IX, X, XI, and XII. In addition, the infratemporal fossa, pterygopalatine fossa, and middle ear structures were presented. Finally, the vertebral artery segments (v2-v4) and the internal carotid artery, including the petrosal and cavernous segments, were dissected and documented. The specimen was 3D scanned by photogrammetry 3D, refined with 3D modeling software, and uploaded to virtual reality and web visualization.

Results: Seven photorealistic models were created and virtual reality videos demonstrating the relevant anatomy in an immersive environment. The courses of intracranial nerves and the associated vascular and soft tissue anatomy were systematically captured from both intracranial and exocranial viewpoints, creating an accurate 360° virtual depiction of the pertinent anatomy.

Conclusion: The 3D 360° photogrammetric models developed in this study may allow a better understanding of essential intracranial and extracranial structures of the skull base. These models facilitate customizable views and represent a valuable, freely accessible resource that complements traditional dissections, photographic atlases, and conventional 3D models.