Mastoid cavity obliteration and Vibrant Soundbridge implantation for patients with mixed hearing loss.

OBJECTIVES/HYPOTHESIS: To review the results of obliteration of a preexisting mastoid cavity with abdominal fat and Vibrant Soundbridge implantation in patients with mixed hearing loss (MHL) and to compare the data with results of Vibrant Soundbridge implantation in patients with MHL without mastoid cavity and with pure sensorineural hearing loss (SNHL).

STUDY DESIGN

Retrospective chart analysis of 10 patients (10 ears) with MHL and preexisting mastoid cavity, 18 patients (19 ears) with MHL alone and nine patients (10 ears) with SNHL treated in one tertiary referral center.

METHODS

Vibrant Soundbridge implantation and obliteration in case a mastoid cavity existed previously. Pure tone audiometry (average air-bone gap, average functional gain), speech audiometry (Freiburg Monosyllabic Test) and complication rate were main outcome measures.

RESULTS

Postoperative average air-bone gap was -15.1 ± 21.2 dB in patients with MHL with mastoid cavity obliteration, -7.2 ± 11.4 dB in patients with MHL without mastoid cavity, and -5.7 ± 11.2 dB in patients with SNHL. Average functional gain was 40.0 ± 23.5 dB, 39.7 ± 12.1 dB, and 9.5 ± 10.6 dB. Postoperative speech discrimination rate was 77.9 ± 20.8%, 83.3 ± 13.6%, and 83.6 ± 6.3%. No severe intraoperative or postoperative complications were noted.

CONCLUSIONS

Mastoid cavity obliteration during Vibrant Soundbridge implantation in patients with MHL and preexisting mastoid cavity is a safe procedure. The audiometric results are satisfying and comparable to those of other patient groups implanted with the same device.

LEVEL OF EVIDENCE