Vestibular dysfunction and compensation after removal of acoustic neuroma.

OBJECTIVE

To evaluate vestibular function after unilateral acoustic neuroma surgery via a retrosigmoid approach.

METHODS

Thirty-eight patients were tested using caloric irrigation, static posturography, and the Dizziness Handicap Inventory (DHI) before, and one week to nine months after surgery.

RESULTS

Twenty-six patients were categorized as a response group and 12 as a no-response group on the basis of preoperative caloric irrigation findings. The posturographic parameters and DHI scores at one week after surgery showed significant deterioration in the response group, but not in the no-response group. However, they recovered to the preoperative baseline at 3 months after surgery. The posturographic parameters and DHI scores for older patients tended to be worse than those for younger patients at 6 and 9 months after surgery.

CONCLUSION

Patients in whom caloric responses are retained preoperatively show a temporary disturbance of balance after removal of acoustic neuroma. Disequilibrium after surgery ameliorates to the preoperative baseline within three months due to vestibular compensation, regardless of preoperative vestibular function. It is possible that poorer vestibular compensation may facilitate incomplete recovery in older patients after surgery.