FP03-2. LONG TERM HEARING RESULTS OF STAPES SURGERY FOR OTOSCLEROSIS

Wilko Grolman, Rinze Tange (University of Amsterdam, Netherlands)

Introduction: Stapes surgery for otosclerosis is a rather succesfull treatment for patients with a large air-bone gap due to this disease. Most of the publication on the postoperative hearing results deal with the results an one to five years of follow-up period. There are conflicting statements on the long term results of stapes surgery for otosclerosis in literature. Some authors describe high tone sensorineural  hearing loss (SNHL) while others describe air-bone gap changes during long term follow-up.The objective of our retrospective study was to determine whether the hearing function stays stable after more then 10 years of  follow up and to distinguish the type of hearing reduction.

 Design: A retrospective case controlled study of 147 patients (av.age 36.4 years) with otosclerosis who had stapes surgery during the period 1983-1989. The surgery was performed at Otology department of the ORL clinic of the Academic Medical Centre of University of Amsterdam in the Netherlands.

Measurements: From all subjects a complete history examination was performed and stored in a database. From patients at least three audiographical data (1 preoperative and 2 postoperative) were present. A distinction was made in clinical and mixed type otosclerosis. Bone conduction and air conduction data were compared with ISO 7029-2000 data for age related normal hearing data. 

Results:  Four hundred twenty seven audiograms were evaluated. Averaging these data we found that the reconstruction of the chain by stapes surgery stays stable after more than 10 years. We compared the results with the international standard of statistical distribution of hearing thresholds as function of age (ISO 7029-2000) and found that SNHL occurs during long term follow up and that it is more pronounced especially in cases of mixed type otosclerosis. SNHL is found in the high as well as in the low tones.

Conclusion: Long term follow up of the hearing results after stapes surgery for otosclerosis is important. The reconstruction of the ossicular chain by stapes surgery remains stable during the follow up of more than ten years. When compared with the international standard of statistical distribution of hearing thresholds as function of age hearing loss can be distinguished in long term follow up in cases of stapes surgery for otosclerosis. This loss is more pronounced in older patients with mixed type of otosclerosis.