Histology of the vertebral artery-dural junction: relevance to posterolateral approaches to the skull base

Far lateral craniotomy for disconnection of vertebral dural arteriovenous fistula: how I do it

BACKGROUND

Craniocervical junction (CCJ) vascular abnormalities can be challenging to treat because of the surrounding density of critical neurovascular anatomy. Although most dural arteriovenous fistulas (dAVFs) are now treated with endovascular surgery, dAVFs near the CCJ are often better suited for microsurgical obliteration with precise vascular control.

METHODS

We describe our microsurgical approach to treating dAVFs at the CCJ. This includes a far-lateral approach with a small incision centered over the transverse process of the atlas and circumferential skeletonization of the vertebral artery in addition to clipping the fistula to limit lesion recurrence.

CONCLUSIONS

Definitive microsurgical treatment of CCJ dAVFs can be accomplished using a minimally invasive approach.

Histology of the Porous Oculomotorius: Relevance to Anterior Skull Base Approaches

Objective: Mobilization of cranial nerve III (CNIII) at its dural entry site is commonly described to avoid damage from stretching during approaches to the parasellar, infrachiasmatic, posterior clinoid, and cavernous sinus regions. The histologic relationships of CNIII as it traverses the dura, and the associated surgical implications are nonetheless poorly described. We herein assess the histology of the CNIII-dura interface as it relates to surgical mobilization of the nerve. Methods: A fronto-orbitozygomatic temporopolar approach was performed on six adult cadaveric specimens. The CNIII-dural entry site was resected and histologically processed. The nerve-tissue planes were assessed by a neuropathologist. Results: Histologic analysis demonstrated that CNIII remained separate from the dura within the oculomotor cistern (porous oculomotorius up to the oculomotor foramen). Fusion of the epineurium of CNIII and the connective tissue of the dura was seen at the level of the foramen, with no clear histologic plane identified between these structures. Conclusion: CNIII may be directly mobilized within the oculomotor cistern, while dissections of CNIII distal to the oculomotor foramen should maintain a thin layer of connective tissue on the nerve.