Evaluation of three intraoperative auditory monitoring techniques in acoustic neuroma surgery

Objective: To assess the efficacy of three intraoperative auditory monitori ng techniques: auditory brainstem response (ABR), electrocochleography (ECo G), and direct eight nerve monitoring (DENM). Study Design: A retrospective review of the intraoperative recordings of AB R, ECoG, and DENM was performed. Setting: A private, neurotologic practice. Patients: Sixty-six patients with usable preoperative hearing underwent int raoperative auditory monitoring with ABR, ECoG, or DENM. Interventions: Intraoperative auditory monitoring. Main Outcome Measures: Postoperative pure-tone hearing threshold and word r ecognition scores. Results: OC the 66 patients, 16 (24%) had postoperative serviceable hearing . Five (18%) of the 28 with ABR monitoring, 3 (17%) of the 18 with ECoG mon itoring, and 8 (40%) of the 20 with DENM monitoring had serviceable hearing after surgery. Conclusions: This study suggests that DENM may be more effective than ABR o r ECoG, although the differences in hearing preservation rates are not stat istically significant.