Revision stapes surgery: the "lateralized piston syndrome".

OBJECTIVE

The need for revision stapes surgery has many causes, and among these, we describe a particular displacement of the piston: the "lateralized piston syndrome". The goal of this study is to define criteria and surgical management of this syndrome.

STUDY DESIGN

Retrospective study over 13 years.

SETTING

Tertiary reference center.

PATIENTS

A review of 1,289 consecutive stapes operations revealed 119 revisions (9%) from which 22 cases (18.5%) could be classified under the lateralized piston syndrome.

INTERVENTION

Revision stapedotomy.

MAIN OUTCOME MEASURES

Medical files, preoperative and postoperative audiograms, computed tomographic scans, and operative reports.

RESULTS

The 22 cases presented as a delayed conductive hearing loss in 95.5% of cases. Preoperative computed tomographic scans showed a lateralized piston out of the stapedotomy in 81% of cases and touching the tympanic membrane in 54.5% of cases. Revisions revealed a lateral displacement of the piston out of the entire oval window in 86% of cases, with closure of the stapedotomy in all cases and incus necrosis in 77% of cases. Conventional pistons were fitted in 12 cases. In case of a significantly eroded incus, total prostheses (TORPs) in 6 cases and offset pistons in 4 cases were placed. Air-bone gap (ABG) was closed to within 20 dB in 82% of cases. Air-conduction puretone audiometry improvement was 17.2 dB (standard deviation [SD], 19.2), with a mean postoperative ABG of 16.2 dB (SD, 12.7). Only 1 ear, operated with TORP, had a sensorineural deterioration of 20 dB. With offset pistons, ABG was closed to within 20 dB in 100% of cases with a mean postoperative ABG of 8.8 dB (SD, 7.2).

CONCLUSION

The lateralized piston syndrome was found in 18.5% of stapes surgery revisions. Surgical management was effective in correcting the conductive hearing loss. In the event of significant eroded incus, we observed better results with offset pistons than with TORPs.