Foundations of Advanced Neuroanatomy: Preparation, Dissection, and 3D Photography of Specimens for Skull Base Pedagogy

Introduction: The dissection laboratory lies at the very core of skull base training; however, transitioning from a neophyte to a skilled anatomist and beyond is challenging ordeal, with no clear pedagogical pathway. In parallel, an oft-overlooked aspect of anatomy training is engagement with the processes surrounding the dissection—specimen preparation, and documentation of completed dissections. Our objective was to design and test a technical curriculum focused on these techniques, and to assess their impact on resident neuroanatomy knowledge and skill.

Methods: Under the guidance of a clinical skull base fellow with 2 years of anatomical dissection experience in the Rhoton laboratory (M.P-C.) and two senior staff with more than 15 years of experience each as dissection course faculty (C.L.D., M.J.L.), three neurosurgery residents were instructed in detailed techniques for specimen preparation and dissection documentation. Four consecutive human head specimens underwent bilateral carotid artery cannulation for infusion with an aqueous, formalin-based embalming solution. Bilateral vertebral arteries and veins were cannulated, and test flushes identified and small- to medium-sized cervical vessels, which were suture ligated until fluid egress was only observed from the other cannulas. A 48-hour cycle of intermittent flushing every 8 to 12 hours with interval drainage was then completed. Red and blue thinned latex solutions were injected into the cannulated arteries and veins respectively, using large-bore manual syringes under moderate continuous pressure until latex egress was noted at a contralateral vessel. Specimens were refrigerated at 34F during dissection. Approach-based dissections were conducted including orbitozygomatic, middle fossa, and posterior petrosectomy.

Results: At key steps during each dissection, 3D photographs were acquired using a DSLR camera equipped with a macro lens mounted to a tripod-based sliding plate for stereoscopic capture. Images were selected and prepared for presentation by the dissecting resident, and companion instructional text describing the anatomy and technique was composed. Materials for each step were reviewed with the supervising fellow; once satisfactory results were achieved, dissection proceeded, with definitive images and text marked for publication. Resident participants and supervising staff were surveyed prior to and following the curriculum regarding resident neuroanatomy knowledge and the relative value they assigned each component of the curriculum as a tool for improving operative skills. All study participants and staff reported dramatic improvement in resident knowledge and skill in association with the curriculum. On postcurriculum assessment, photo-documentation was associated with the largest increase in relative educational value, as compared with precurriculum predictions by the same individual.

Conclusion: Advanced neuroanatomy skills include specimen preparation and dissection documentation, in addition to traditional cadaver techniques. Participation in all dissection phases may enhance the educational yield for residents—in particular, documentation of dissections using both photographic and written media, ideally under expert supervision and with a goal of generating publication-quality figures.