Comparative analysis of surgical exposure and freedom between the subtonsillar, endoscope-assisted subtonsillar, and far-lateral approaches to the lower clivus: A cadaveric study

Glossopharyngeal Neuralgia

Glossopharyngeal neuralgia (GPN) is a rare disease that must be differentiated from trigeminal neuralgia. The purpose of this article is to provide a comprehensive review of anatomy, pathophysiology, diagnostic criteria, and several options of treatment for GPN. Lessons learned through our experience of treating GPN are presented in detail, as well as cases of misdiagnosis and diagnostic pitfalls. Microvascular decompression (MVD) should be primarily considered for medically intractable GPN. Techniques employed in MVD for GPN are categorized and described. Especially, we underscore the advantages of the 'transposition' technique where insulating material is positioned 'off' the root entry zone (REZ), instead of 'on' it. We believe this 'off-the-REZ' technique can fundamentally prevent recurrence, if applicable. In addition, Gamma Knife radiosurgery can be an alternative option when a patient is ineligible for MVD, though it is categorized as a destructive procedure.

Posterior fossa endoscopic-assisted surgery: A systematization of its surgical corridors

INTRODUCTION

The use of endoscopic-assisted techniques in neurosurgery has been implemented to improve better visualization and predict extent of resection. We aim to systematize the posterior fossa surgical regions and the endoscopic surgical corridors providing a quick reference of the anatomy and surgical nuances.

METHODS

A retrospective review of patients undergoing endoscopic-assisted surgery of the posterior fossa at a single institution between 2019 and 2020 was conducted along with a description of the microsurgical anatomy from cadaveric specimens and surgical cases.

RESULTS

The posterior fossa was segmented into three topographic regions, (upper, middle and lower), with three surgical corridors within each of these. Upper region is accessed through a supracerebellar infratentorial approach and comprises the pineal and pericuadrigeminal region constituted by the median corridor, the lateral corridor, and the extreme lateral corridor. Middle region is accessed through a retrosigmoid approach and comprises the cerebellopontine angle region constituted by the supralateral corridor containing the upper neurovascular complex (NVC), the median corridor containing the median NVC, and the infralateral corridor containing the lower NVC. The lower region is accessed through a far-lateral approach and contains the craniocervical junction region constituted by the upper corridor in between the VII-VIII and IX cranial nerves (CNs), the median corridor between the X and XI CNs, and the lower corridor between the cranial and spinal rootlets of the XI CN.

CONCLUSION

We propose a simple and concise systematization, dividing the area into three regions with predefined corridors.