Intra-operative electrocochleography in stapedectomy and ossicular reconstruction.

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of intraoperative electrocochleography (ECOG) in predicating the postoperative hearing improvement in surgery for conductive hearing loss.

STUDY

DESIGN

This study was a prospective study of 22 patients undergoing intraoperative electrocochleography during a stapedectomy.

SETTING

The study was performed in a tertiary referral center.

PATIENTS: Intraoperative electrocochleography was performed in 22 patients 27-73 years of age undergoing a stapedectomy for otosclerosis under general anesthesia.

INTERVENTION: For each patient, the N1 threshold to click stimulation was measured intraoperatively, before and after the reconstruction.

MAIN OUTCOME MEASURES: The intraoperative ECOG thresholds were compared with the pre and postoperative audiograms.

RESULTS

Postreconstruction ECOG's demonstrated improvements in the N1 threshold in 19 cases, and were unchanged in 1 case. In each of these cases, improvement in the intraoperative N1 threshold corresponded with improvement in the postoperative audiogram compared with the preoperative studies. In two other cases the postreconstruction ECOG was nearly unobtainable, despite improved hearing postoperatively.

CONCLUSION

Intraoperative ECOG appears to be an effective tool for verifying the functional integrity of ossicular reconstructions as in stapedectomies. We speculate that intraoperative ECOG may allow the surgeon to "fine tune" the reconstruction to optimize the hearing results.