Adjunctive use of endoscopy during posterior fossa surgery to treat cranial neuropathies

OBJECTIVE: The objective of this study was to determine the utility and saf ety of rigid endoscopy as an adjunct during posterior fossa surgery to trea t cranial neuropathies. METHODS: A suboccipital craniotomy was performed for 19 patients with non-n eoplastic processes involving the Vth, VIIth, and/or VIIIth cranial nerves. Ten patients with trigeminal neuralgia (n = 8), hemifacial spasm (n = 1), or intractable tinnitus (n = 1) underwent primarily microvascular decompres sion procedures. One patient with geniculate neuralgia underwent nervus int ermedius sectioning combined with microvascular decompression. Eight patien ts underwent unilateral vestibular nerve neurectomies for treatment of Meni ere's disease. A 0- or 30-degree rigid endoscope was used in conjunction wi th the standard microscopic approach for all procedures. RESULTS: All patients experienced resolution or significant improvement of their preoperative symptoms after posterior fossa surgery. The endoscope al lowed improved definition of anatomic neurovascular relationships without t he need for significant cerebellar or brainstem retraction. Cleavage planes between the cochlear and vestibular nerves entering the internal auditory canal and sites of vascular compression could not be microscopically observ ed for several patients; however, endoscopic identification was possible fo r all patients. There were no complications related to the use of the endos cope. CONCLUSION: The rigid endoscope can be used safely during posterior fossa s urgery to treat cranial neuropathies, and it allows improved observation of the cranial nerves, nerve cleavage planes, and vascular anatomic features without significant cerebellar or brainstem retraction.