Prognosis of Tinnitus After Acoustic Neuroma Surgery-Surgical Management of Postoperative Tinnitus

OBJECTIVE: Tinnitus is a bothersome symptom for patients with acoustic neuroma. We studied the possibility of surgical control of postoperative tinnitus associated with acoustic neuroma. METHODS: Postoperative changes and prognosis of tinnitus were studied in 367 patients treated surgically via a lateral suboccipital retrosigmoid approach. RESULTS: Postoperative prognosis of tinnitus was as follows: resolved in 20%, improved in 22%, unchanged in 35%, changed in 10%, and worsened in 14% of 290 patients who had preoperative tinnitus, and no tinnitus in 78% and appeared in 22% of 77 patients without preoperative tinnitus. Prognosis of postoperative tinnitus was influenced by age, tumor size, preoperative hearing acuity, types of preoperative hearing disturbance, and conditions of the cochlear nerve after tumor resection. Worse prognosis of postoperative tinnitus in the preoperative tinnitus group was found in younger patients, smaller tumor size, better preoperative hearing function, and normal or retrocochlear type of hearing disturbance. Regarding the conditions of the cochlear nerve after tumor resection, prognosis of tinnitus was significantly worse in the group of anatomically preserved cochlear nerve without useful hearing than in the group of cut cochlear nerve. CONCLUSIONS: Deciding whether to cut the cochlear nerve during acoustic neuroma surgery by referring to a flowchart, we proposed in cases where hearing preservation is not intended or judged less possible contributes to controlling postoperative tinnitus. However, regardless of whether the cochlear nerve was cut intraoperatively, tinnitus remained unchanged in 37% of patients, suggesting that their tinnitus originates in the brainstem or post-brainstem pathways before surgery, and it is considered difficult to control postoperative tinnitus in these cases.