Tympanosclerosis involving the ossicular chain: mobility of the stapes in association with hearing results.

Conclusion: The preoperative bone conduction level provides not only prognostic information but also information on the mobility of the stapes in tympanosclerosis. The surgical results depend upon the stapes mobility.

Objectives: We aimed to evaluate operative findings and hearing results of tympanosclerosis involving the ossicular chain, in order to understand the pathophysiology and to establish better surgical treatment of tympanosclerosis.

Patients And Methods: Between January 1998 and March 2004, 29 patients (29 ears) with tympanosclerosis involving the ossicular chain underwent tympanoplasty at our hospital. Patients with myringosclerosis only, or with an associated cholesteatoma, were excluded from this study. The clinical and operational records and pre- and postoperative pure tone audiograms were reviewed retrospectively.

Results: Intact canal wall tympanoplasty was applied to all 29 patients. A non-staged operation was performed on 21 patients, and a staged operation was performed on the remaining 8 patients. In 25 patients (86.2%), the sclerotic lesion of the ossicles was located in the epitympanum. In the remaining four, the sclerotic lamella coated only the ossicular chain. On average, the preoperative air conduction hearing level of 57.9 dB was significantly improved to 46.3 dB after tympanoplasty. The success rate of middle ear surgery was 65.5% (19 of 29 patients), according to the criteria of the Otological Society of Japan. In 16 patients (55.2%), the mobility of the stapes was preserved (group A), while in the remaining 13 patients (44.8%), the stapes was fixed (group B). The mean preoperative bone conduction of 25.5 dB in group A was significantly better than that of 37.2 dB in group B. The hearing result significantly improved in group A but not in group B. The success rates were 75% (12 of 16 patients) in group A and 53.8% (7 of 13 patients) in group B.