Evaluation of three intraoperative auditory monitoring techniques in acoustic neuroma surgery.

OBJECTIVE

To assess the efficacy of three intraoperative auditory monitoring techniques: auditory brainstem response (ABR), electrocochleography (ECoG), and direct eight nerve monitoring (DENM).

STUDY

DESIGN

A retrospective review of the intraoperative recordings of ABR, ECoG, and DENM was performed.

SETTING

A private, neurotologic practice.

PATIENTS: Sixty-six patients with usable preoperative hearing underwent intraoperative auditory monitoring with ABR, ECoG, or DENM.

INTERVENTIONS: Intraoperative auditory monitoring.

MAIN OUTCOME MEASURES: Postoperative pure-tone hearing threshold and word recognition scores.

RESULTS

Of the 66 patients, 16 (24%) had postoperative serviceable hearing. Five (18%) of the 28 with ABR monitoring, 3 (17%) of the 18 with ECoG monitoring, 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 or ECoG, although the differences in hearing preservation rates are not statistically significant.