Selective retromastoid vestibular neurectomy for intractable Ménière's disease: a technical note.

Background: Retrosigmoid vestibular neurectomy is considered to be the most effective and safe procedure to control intractable vertigo associated with Ménière's disease while preserving hearing. The surgical procedure of retrosigmoid vestibular neurectomy at the cerebellopontine angle has been well established. Here, we provide for otologic surgeons additional details about the procedure, with special attention to the anatomic features to emphasize our technique, which enables an adequate sectioning of the vestibular fibers on the cochlear nerve close to the overlapping zone containing large-caliber vestibular fibers and small-caliber cochlear fibers.

Methods: We used the lateral decubitus position to enter the cerebellopontine angle. The cerebellum was gently retracted to expose the cerebellomedullary cistern, which was then opened to drain the cerebrospinal fluid for slacking of the cerebellum. The underlying lower cranial nerves IX, X, and XI were identified. The retractor was then moved upward to locate the internal acoustic meatus and the complexes VIII-VII. Adjacent to the internal auditory canal, a longitudinal incision, about 3 mm long and 0.5 mm away from the landmarks of arteriole or cochleovestibular cleavage plane, was made on the cochlear nerve. A surgical separation plane was bluntly created using a microdissector between the two components, and the vestibular nerve was sharply sectioned with microscissors.

Results: We re-examined the patients' hearing status, word recognition (speech discrimination) skill, functional levels, and frequency of vertiginous episodes 1 month and at all 6-month intervals after the surgery. At 2 years after surgery, vertigo was completely controlled, indicating a 100% cure rate.

Conclusion: Sectioning of vestibular fibers was performed along the cochleovestibular cleavage landmark on the cochlear nerve where the overlapping zone was located, allowing for a safe and adequate vestibular neurectomy, while most of the cochlear fibers were spared.