Middle-Ear Implants: 2012
Klein, Nardelli, Stafinski (2012) report that there are two fully implantable middle-ear devices available. The Esteem Hearing System is manufactured by Envoy and FDA approval was granted in 2010. The Carina Fully Implantable Hearing Device (also known as the Fully Implantable MET) is manufactured by Otologics, and is not yet FDA approved.
The authors report there is no (known) systematic review of fully implantable hearing systems published, to date. Therefore, they "screened" some 7,700 citations from which they selected 30 articles for review. Only 20 of the selected articles met eligibility requirements for the purpose of their review. Thus, the articles gathered on the Esteem (likely) reflect some 105 patients (mostly males) across five countries. The articles gathered on the Carina (likely) reflect some 68 patients (roughly equal numbers of males and females) across seven countries.
Klein, Nardelli, and Stafinski report that the Esteem has an estimated battery life of four and half years (when used 24 hours daily) to nine years (when used eight hours daily) and the estimated cost is $30,000. The Carina system is rechargeable and takes approximately 60 to 90 minutes to charge daily, the estimated cost is $15,000. With regard to Esteem and the 105 patients reported, the most common adverse effects noted were chorda tympani nerve damage or taste disturbance, occurring in some 30 percent of patients. Facial weakness was also reported in eight percent of the patients and was permanent in two patients. Seven explants and five revision surgeries were reported. With regard to Carina and the 68 patients reported, the most common negative issue was device failure or malfunction (occurred in 18 percent). One failure was due to head trauma and in nine cases the device failed to charge properly. Four units were explanted due to device malfunction and three were revised.
The authors note that despite limitations, middle-ear implants (MEIs) seem to generally provide functional gain comparable to traditional hearing aids and (successful) MEIs generally provide greater improvements in speech recognition and quality of life for patients able to wear traditional hearing aids. For patients unable to wear traditional hearing aids, MEIs offer improvements as compared to no treatment. The authors state, "However, patients should be informed of the relatively high risk of surgical complications involved with device implantation, particularly with the Esteem device…"
For More Information, References and Recommendations
Briggs RJS, Eder HC, Seligman PM, Cowan RSC, Plant KL, Dalton J, Money DK, Patrick JF. (2008) Initial Clinical Experience with a Totally Implantable Cochlear Implant Research Device. Otology & Neurotology 29(2):114-119.
Haynes DS, Young JA, Wanna GB. (2010) Middle-Ear Devices from Past to Present. ENT & Audiology News 19(1):82-84.
Klein K, Nardelli A, Stafinski T. (2012) A Systematic Review of the Safety and Effectiveness of Fully Implantable Middle Ear Hearing Devices: The Carina and Esteem Systems. Otology & Neurotology 33:916-921.
Tysome JR, Moorthy R, Lee A, Jiang D, O'Connor AF.(2010) Systematic Review of Middle Ear Implants: Do They Improve Hearing as Much as Conventional Hearing Aids? Otology & Neurotology 31(9):1369-1375.