Surgical Outcomes With Cochlear Implantation in Patients With Enlarged Cochlear Aperture: A Systematic Review.

Objective: Evaluate surgical outcomes in patients with enlarged cochlear aperture (ECA) after cochlear implantation.

Databases Reviewed: PubMed, EMBASE, and Scopus.

Methods: A systematic review was performed using standardized methodology. Studies were included if they included subjects with ECA who underwent cochlear implantation. Exclusion criteria included non-English articles, abstracts, letters/commentaries, case reports, and reviews. Bias was assessed using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool.

Results: Out of 1,688 identified articles, 7 articles representing 23 subjects with ECA were included. Publication rates increased between the period of study from 2009 to 2018. Four studies were level 4 evidence and three studies were level 3 evidence. In total, 20 subjects underwent cochlear implantation. Cerebrospinal fluid gushers were encountered in the majority of cases that reported complications (16/17, 94.1%); one patient developed postoperative meningitis, and another experienced postimplantation facial nerve stimulation. No study provided measurements on cochlear aperture size or defined size criteria used to identify ECA. Four studies recognized X-linked deafness to be associated with ECA, and the most common mutation was in POU3F4 gene.

Conclusion: An association exists between ECA and cerebrospinal fluid gusher, underscoring the importance of reviewing preoperative imaging. Size criteria are not well defined, and there is a paucity of data with respect to normative measurements. Many cases of ECA may give a genetic link. Although level of evidence of current studies remains modest, ECA reports have increased and will likely continue to expand with advancements in imaging and genetic testing.