Investigating Additional Cochlear Parameters: A follow-up systematic review and meta-analysis

Objectives: The movement towards personalization of cochlear implantation has continued to generate interest about variabilities in cochlear size. In a recent meta-analysis, Atalay et al. (2022) examined organ of corti length, cochlear lateral wall, and “A” value and found that most covariates, other than congenital sensorineural hearing loss, did not impact cochlear size via these measurements. However, no meta-analysis exists on how patient-specific variables could impact other cochlear size measurements, such as cochlear height (CH), and “B” value (defined as the distance between opposite lateral walls and perpendicular to “A” value). The purpose of this systematic review and meta-analysis is to examine how patient-specific variables impact additional cochlear size measurements to assist clinical decision-making. Databases reviewed: A systematic review for cochlear size measurements using PRISMA methodology was performed using PubMed, CINAHL, and MEDLINE from database inception to October 1st, 2022. Methods: Search terms used included English, cochlea, size, histology, anatomy, and human. Inclusion criteria were measurements for human cochlea, full-text articles, and articles in English. Primary measurements were “B” value and CH, as these measurements differ from the recent meta-analysis on this topic. Cochlear duct length (CDL) was also included. A random-effects continuous model for meta-analysis was performed. Measurements were stratified by gender (male/female) and disease type (sensorineural hearing loss (SNHL)/conductive hearing loss (CHL)). Results: A total of 7 articles met final inclusion criteria from a total of 674 articles received on initial search, resulting in 2263 total human cochleae. There was a statistical difference between male CDL (n = 681 cochlea) compared to female CDL (n = 657) from four articles (p