Abstract

Cochlear implantation is a very effective therapy for deafness. However, aberrant cochlear anatomy poses technological obstacles, with varying results observed. This study aimed to comprehensively evaluate and compare the varied results of cochlear implantation in abnormal cochlear anatomy. A comprehensive search of electronic databases was conducted from January 2014 to 4 May 2024. Studies reporting outcomes of cochlear implantation in patients with anomalous cochlear/vestibular anatomy were included. Primary outcomes were hearing, speech perception, and quality of life. The quality of the included studies was evaluated using the Newcastle-Ottawa Scale and the Cochrane tool. A total of 24 studies comprising 1,123 patients out of 29 included studies. Common anomalies were Mondini dysplasia (30 studies), common cavity (12 studies), and cochlear hypoplasia (8 studies). Short-term (3 years) follow-up showed no significant differences. Complication rates were higher with anomalous anatomy (OR 1.78, 95% CI 1.27-2.48, and p-value = 0.001). Outcomes were better with electrode designs suitable for an anomalous cochlea. In individuals with abnormal cochlear anatomy, cochlear implantation results were poor in the short term but similar to normal cochleae in the medium-to-long term for speech perception. Careful patient selection, improved imaging, tailored electrode arrays, and surgical competence all improved results. Larger multicenter prospective trials using standardized methodologies are required.

Key words: Cochlear implantation, anomalous cochlear anatomy, Mondini dysplasia, speech perception, systematic review