Comparison of the Outcome between Lateral, Perimodilar and Midscalar Electrodes in Cochlear Implantation Surgery: A Systematic Review

Abstract Background Cochlear Implants are neuroprosthetic devices that are surgically implanted receiver-stimulator package and electrode array, which when used with external sound processor can produce a sensation of sound in the recipient in people who are deaf and can't benefit from acoustic hearing aids or middle ear implants or bone conduction devices. Objective To compare Lateral, Midscalar, and Perimodiolar electrodes, by using a systematic review as regards: trauma to the cochlea, hearing preservation (if there is a residual hearing). Material and Methods The search on Google Scholar, Scopus and PubMed using the following keywords (lateral wall electrode, Midscalar electrode, perimodiolar electrode, cochlear implant, hearing preservation, cochlear trauma). The inclusion criteria: randomized control, case control, retrospective studies, human living patients, patients with profound sensory neural hearing loss (SNHL). The quality of relevant studies was assessed by NIH quality assessment tool for the type of study (“Study Quality Assessment Tools/National Heart, Lung and Blood Institute (NHLBI),”2019). 186 articles were yielded, from which 77 articles met our criteria. After duplicates removal and restricted to English language, 67 articles were screened in title/Abstract screening, while 31 articles were screened in full text screening were included. Results Our study showed that hearing preservation rate with lateral electrode was 53%. Also, hearing preservation with Mid-Scala electrode was 58%. Ratio of cochlear trauma with Perimodiolar electrode was 29% (7%, 55%). Hearing preservation with Lateral electrode versus Perimodiolar electrode odds ratio was 2.20 favoring lateral electrode over Perimodiolar electrode. Hearing preservation with Lateral electrode versus Mid-Scala odd ratio was 0.79 favoring no electrode type over the other. Preserving functional residual hearing in cochlear implant is higher in lateral electrode and Midscalar than in Perimodiolar electrode. Conclusion Preserving functional residual hearing in cochlear implant is higher in lateral electrode and Midscalar than in Perimodiolar electrode.