Cochlear Implantation in Children with Anomalous Cochleovestibular Anatomy: A Systematic Review

Objective. To determine the influence of inner ear dysplasia on both surgical and audiologic outcomes following pediatric cochlear implant (CI) surgery. Data Sources. MEDLINE (1982-2009) and data from Massachusetts Eye and Ear Infirmary. Review Methods. A systematic review of the literature was performed. Variables assessed included age at implantation, duration of CI use, radiologic and operative findings, and speech perception outcome data. Results. The initial search yielded 1326 articles. Including data from our own study, twenty-two fulfilled criteria for inclusion, representing 311 patients. Data for bilateral implants were recorded only for the first implant. Data on simultaneous bilateral implants were not recorded. The most common anomaly seen was large vestibular aqueduct (89/311 or 29%). When comparing patients with mild-moderate or severe dysplasia, rates of cerebrospinal fluid gusher were 31% versus 35% (odds ratio [OR] = 0.50), anomalous facial nerve anatomy was seen in 11% versus 51% (OR = 0.15), and postoperative speech perception abilities were found in 84% versus 54% (OR = 1.93), respectively. A large heterogeneity was found among studies regarding all outcome measures. Conclusion. Although we found that severe inner ear dysplasia was associated with increased surgical difficulty and lower speech perception, the lack of uniformity in published clinical data limited the strength of these results. Standardization of surgical and radiologic reporting as well as more consistent speech perception testing is needed to better determine the association between anomalous cochleovestibular anatomy and clinical outcomes.