Intraoperative electrocochleography during endolymphatic sac surgery: clinical results

Thirty-eight patients who underwent endolymphatic shunt surgery with intraoperative electrocochleography were questioned regarding control of symptoms. The average follow-up period was 2 years (range, 7 to 40 months). Sixteen (42%) patients showed improvement in the intraoperative electrocochleography potential, 12 (32%) showed worsening, and 10 (26%) showed no change. Complete or substantial control of dizziness was achieved in 36 (95%) patients, and insignificant control in only 2 (5%) patients. Hearing improvement was noted in 4 (11%) patients, and hearing loss in 13 (34%). No correlation was found between intraoperative electrocochleography improvement and dizziness control. However, three of the four patients who had hearing improvement also had the greatest improvement in intraoperative electrocochleography recording. Intraoperative electrocochleography may help the surgeon more accurately identity the true endolymphatic sac and duct.