[Tympanosclerosis incidence among patients with chronic suppurative otitis media].

Objective: To study the general incidence of tympanosclerosis among patients with chronic suppurative otitis media(CSOM), and to explore the type of hearing loss and the relationship between the hearing loss and the degree and site of tympanosclerosis in CSOM patients.

Method: One hundred and one patients with CSOM were studied retrospectively. A full history was taken and thorough ENT examinations were carried out. Pure tone audiograms(PTA) of all patients were measured and analysed. The operative findings of tympanosclerosis were also inspected and analysed.

Result: The incidence of tympanosclerosis was found to be 35. 64 percent. Most tympanosclerosis cases had dry ear (77. 78 per cent). The majority of hearing loss associated with tympanosclerosis was of the conductive type. Of the 92. 56 percent who had myringosclerosis, the PTA showed an AB gap <40 dB. When sclerosis affected both tympanic membrane and middle ear, 45. 45 per cent of patients had an AB gap >40 dB.

Conclusion: The exact aetiology and pathogenesis of tympanosclerosis is as yet not well known. There is a direct relationship between the degree of hearing loss and the degree and site of tympanosclerosis.