Middle Ear Cholesteatoma : Surgical Treatment, Follow-up and Hearing Restoration

Abstract: Although middle-ear cholesteatoma is a major topic in otological research, its etiology and pathogenesis remain unclear. Pediatric cholesteatoma is considered more aggressive than adult cholesteatoma, as it has a higher rate of growth, is more often infected and exhibits wider extension. Higher incidence of residual and recurrent disease after surgical treatment of pediatric cholesteatoma has been observed in most studies. In this study, the results are presented from a canal wall down (CWD) obliteration technique used in 330 adult patients (Paper I) with cholesteatoma, evaluated at 1, 3 and 6 years following surgery. Additionally, results are offered from 57 pediatric patients (Paper II) using identical surgical technique and compared with adults. The surgical and hearing outcomes in both groups showed a low incidence of residual and recurrent disease and a high rate of ear water resistance without infection. The results were unrelated to the severity and extension of disease, as well as to age and previous surgery. No differences were found in outcomes between adult and pediatric cholesteatoma patients.The thesis also describes the use of diffusion-weighted magnetic resonance imaging (DW-MRI) (Paper III) in follow-up examinations of adult cholesteatoma patients undergoing surgical treatment. Non-echo planar diffusion-weighted imaging (Non-EPI DW-MRI)increased the accuracy of clinical examinations. It is concluded that the use of non-EPI DW-MRI should be mandatory in clinical follow-ups after cholesteatoma surgery. In Paper IV a relatively new mode of hearing rehabilitation was investigated, with an active middle ear implant (AMEI), in patients with chronically disabled ears. Functional hearing results were compared with the previous use of conventional hearing aids before and after AMEI implantation. Moreover, the consequences of positioning of the implant in the middle ear were evaluated using cone beam computed tomography (CBCT), a modification of conventional computed tomography. The hearing results, assessed with AMEI, were found to be less dependent on the precise positioning of the floating mass transducer(FMT) against the round window membrane (RWM) than was anticipated. Further, the hearing results were noted to be comparable with those with conventional hearing aids and even superior at high frequencies.