Cochlear implantation in patients afflicted with inner ear malformations – the Pécs experience

Abstract

Purpose: To successfully analyze the surgical and audiological results of cochlear implantation in patients afflicted with inner ear malformations. This study briefly presents our surgical strategies, the selected implants and the audiological results.Method: Objective hearing threshold was measured using an auditory brainstem response and middle latency response audiometry. Structural imaging of high resolution temporal bone computer tomography and inner ear MR scan was performed in support of all patients. Images revealed bilateral cochlear malformation in seven patients. Three ears with common cavity deformity, two ears with incomplete partition type I and three ears suffering from cochlear hypoplasia were all rehabilitated using cochlear implantation. The type of the electrode and the surgical technique were individually determined reflective of the type of malformation. The success of the surgery and potential postoperative complications were duly noted and fully registered. Postoperative audiological measurements were performed and the results were analyzed.Results: The average audiological follow-up was 40.3 months. The average free field, pure-tone threshold of speech frequencies (0.5–3 kHz) gained postoperatively were within the range of 32.5–41.6 dB. In two of the procedures, a cerebrospinal fluid gusher did occur and was successfully managed intraoperatively, all without any postoperative complications.Conclusion: Temporal bone high resolution CT and inner ear MRI imaging are mandatory to detect and characterize the inner ear malformation. Early implantation of malformed cochlea is crucial towards achieving ideal postoperative audiological results. Notably, an intraoperative gusher is not regarded as a contraindication of the cochlear implantation.