A Systematic Review of the Safety and Effectiveness of Fully Implantable Middle Ear Hearing Devices: The Carina and Esteem Systems

Objective: To examine the safety and effectiveness of fully implantable middle ear devices in the treatment of hearing loss. Data Sources: MEDLINE, EMBASE, The Cochrane Library, Web of Science, CINAHL, PsycINFO, and the Centre for Reviews and Dissemination were searched without date or language limits. Study Selection: Titles and abstracts of 7,700 citations were screened, and 30 articles were selected for full review, of which, 7 articles on the Esteem and 13 on the Carina met the study's eligibility criteria. Data Extraction: Information was extracted using a pretested data abstraction form, and study quality was assessed using the Oxford Centre for Evidence-Based Medicine Levels of Evidence. Data Synthesis: Because of heterogeneity across studies, meta-analysis was not performed, and comparisons were made by structured review. Conclusion: The majority of studies were quasi-experimental, prepost comparisons of aided and unaided conditions. Complication rates with the Esteem were higher than with the Carina, and most commonly included taste disturbance. However, device failure was common with the Carina, predominately related to charging difficulties. For both devices, clinically significant improvements in functional gain, speech reception, and speech recognition over the unaided condition were found. In studies comparing the Esteem or Carina to hearing aids, findings were mixed. Although improvements in functional gain were similar to those for hearing aids, speech recognition and quality of life were greater with the implants. Despite limited evidence, these devices seem to offer a relatively safe and effective treatment option, particularly for patients who are medically unable to wear conventional hearing aids.