How Often Does Stapedectomy for Otosclerosis Result in Endolymphatic Hydrops?

Objectives: 1) To evaluate the long-term (>= 10 year) clinical incidence of endolymphatic hydrops (EH) after stapedectomy for otosclerosis, using low-frequency sensorineural hearing loss (LFSNHL) as a marker for EH. 2) To determine the histologic incidence of EH in human temporal bone specimens (TBS) with a history of stapedectomy for otosclerosis. 3) To determine the histologic incidence of EH in a control group of human TBS. Study Design: Retrospective review and temporal bone study. Setting: Tertiary medical center and temporal bone pathology laboratory. Patients: Patients with otosclerosis, human TBS with otosclerosis, and human TBS with presbycusis as the control group. Intervention: Pure-tone audiometry, temporal bone pathology. Main Outcome Measures: 1) LFSNHL, defined as >10 decibel elevation of bone conduction thresholds at 250 and 500 Hz, after correcting for age-related hearing loss (per ISO 7029). 2) Histologic assessment of EH. Results: In patients with otosclerosis, 8 of 110 (7.3%) operated patients versus 3 of 123 (2.4%) nonoperated patients developed LFSNHL (p = 0.08). No patients with LFSNHL had other symptoms of EH. In TBS with otosclerosis, 11 of 93 (11.8%) operated TBS versus 3 of 156 (1.9%) nonoperated TBS had evidence of EH (p<0.001). In the control group of TBS with presbycusis, 9 of 253 (3.5%) had EH. Conclusion: The long-term incidence of LFSNHL, a marker for EH, in patients with otosclerosis was not significantly higher in those who underwent stapedectomy. The histologic incidence of EH, however, was significantly higher in TBS that had undergone stapedectomy compared with nonoperated TBS or a control group of TBS.