The Course of the Trochlear Nerve Presented via a 3-Dimensional Photorealistic Anatomic Model

Abstract

Several factors contribute to the anatomical complexity of the trochlear nerve including small diameter, complex and longest intracranial course, deep location, and numerous neurovascular relationships. 3-D photorealistic model of cranial nerves provides detailed and immersive representation of the anatomy, enabling to improve surgical planning, advanced surgical research and training. The purpose of this paper is to present a 3-dimentional photogrammetric study for a more intuitive and interactive way to explore and describe the entire course of trochlear nerve. Two injected-fixed head human specimens (4 sides) were examined. The dissection protocol was divided into: step 1) brain hemisphere exposure, step 2) hemispherectomy dissecting all cranial nerves and partial removal of the free edge of the tentorium, step 3) middle fossa and lateral wall of cavernous sinus exposure, step 4) orbital exposure. A detailed 3-D photogrammetric model was generated for each dissection step. Four main volumetric models were generated during a step-by-step layered dissection of the entire nerve pathway highlighting its different segments. Finally, a full and integrated model of the entire course of the nerve was created. The models are available for visualization on monoscopic display, virtual, and augmented reality environment. The present photogrammetric model provides a more comprehensive understanding of the nerve's anatomy in its different segments, allows for customizable views thus simulating different perspectives, and can be a valuable alternative to traditional dissections. It is an advanced tool for surgical planning and surgical simulation as well as virtual reality representation of the anatomy.