Middle Ear Implants for Rehabilitation of Sensorineural Hearing Loss: A Systematic Review of FDA Approved Devices

Objective: To systematically review the safety and efficacy of the 3 Food and Drug Administration-approved middle ear implant (MEI) systems currently in use for the rehabilitation of sensorineural hearing loss. Data Sources: MEDLINE and Cochrane Library databases were systematically searched by 2 independent reviewers. Study Selection: An initial search yielded 3,020 articles that were screened based on title and abstract. A full manuscript review of the remaining 80 articles was performed, of which 17 unique studies satisfied inclusion criteria and were evaluated. Data Extraction: Variables including functional gain, speech recognition score improvement, audiometric threshold shift following surgery, adverse events, and patient reported outcome measures were recorded. Study quality was appraised according to author conflict of interest, prospective or retrospective study design, inclusion criteria, number of patients, proper use of study controls, outcome measures reported, length of follow-up, and level of evidence. Data Synthesis: Heterogeneous outcome reporting precluded meta-analysis; instead a structured review was performed using best available data. Conclusion: The majority of studies evaluating the safety and efficacy of MEIs are retrospective in nature with limited follow-up. To date, no prospective randomized controlled trial exists comparing contemporary air conduction hearing aid performance and MEI outcomes. Based on available data for patients with sensorineural hearing loss, functional gain and word recognition improvement seems similar between conventional hearing aids and MEIs, whereas patient-perceived outcome measures suggest that MEIs provide enhanced sound quality and eliminate occlusion effect.