Журнал фонетики и аудиологии
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Indication and Timing of Surgery for Cochleovestibular Neurovascular Compression Syndrome

Tomomi Okamura, Takafumi Nishizaki, Norio Ikeda, Shigeki Nakano, Makoto Ideguchi, Natsumi Fujii and Takeshi Okuda

Objective: Optimal surgical indications for cochleovestibular neurovascular compression syndrome (CNVC) remain controversial. We examined the surgical indications and timing of surgery for CNVC.
Methods: The surgical outcomes of 30 patients (32 sides) with vertigo, tinnitus and hearing loss were evaluated. CNVC was diagnosed according to five items for clinical features with a scoring system of 1 or 0 based on the following features: a history, neurological and otological findings, an ABR evaluation, and vascular contact with the eighth cranial nerve on MR or air CT imaging. Patients with scores of 4-5 were diagnosed with CNVC. In addition, three modulation types of tinnitus using median nerve stimulation were evaluated in CNVC (28 sides) and other diseases (12 sides), and classified as suppression (S-type), no change (N-type), and excitation (E-type).
Results: At early time, results of 16 sides evaluated using the modulation test before surgery for CNVC, the relationship between modulation of tinnitus and surgical results was evaluated. The ratio of the tinnitus intensity early after the surgery to that before the surgery was significantly lower for the S-type than for the other two types (P<0.01). At one year follow-up, the results of 32 sides were excellent in 8 sides, good in 19 sides, fair in 2 sides and poor in 3 sides. The duration of preoperative symptoms in the excellent group (1.9 ± 6.7 years) was shorter than that in the good group (5.8 ± 5.8 years). Results of CNVC with a chief complaint of vertigo and the duration of symptoms over 15 years and CNVC with a chief complaint of tinnitus and the duration of symptoms over 3 years was not always satisfactory.
Conclusion: Indications for good outcomes are limited and need to consider not only the duration of symptoms, but also the modulation of tinnitus. Our findings suggest that the timing of surgery for CNVC with a complaint of vertigo should be within about 15 years, but that for CNVC with tinnitus should be within 3 years of onset of symptoms. Furthermore, some patients with S-type of less than 6 years are good candidates for surgery.