Authors' objectives:

This review of the evidence assess the effectiveness and cost-efffectiveness of bone-anchored hearing aids (BAHAs) in improving the hearing of people with conduction or mixed hearing loss.

Authors' results and conclusions: Safety: - BAHA has been implanted safely in adults and children with success rates of 90 per cent or higher in most studies. No mortality or life-threatening complications have been reported. - Re-operation rates for tissue reduction or repositioning of the fixture were generally under 10 per cent for adults, but were as high as 25 per cent for children. - Adverse skin reaction around the skin-penetration site was the most common complication reported. Occurring in 7.5 per cent to 30 per cent of patients. Most of these conditions were successfully treated with antibiotics, and only 1 per cent to 2 per cent required surgical revision with less than 1 per cent requiring removal of the fixture. - Other complications included failure of the titanium fixture to integrate with the bone and loss of fixture and/or the connector due to trauma or infection. Effectiveness: - Studies confirmed that the BAHA is appropriate for people who have conduction or mixed hearing loss, missing ear canal, or discharging middle ear infection and who are not candidates for surgical repair. - Objective hearing measurements and patient satisfaction surveys showed that the BAHA significantly improved the hearing threshold and speech discrimination in environments with or without background noise for former users of conventional bone conduction hearing aids. The outcomes were ambiguous for former users of air conduction hearing aids. - The BAHA has been shown to reduce the frequency of ear infection and reduce discharge from the ear among patients with severe discharging middle ear infection. - Patients have reported that the BAHA improved their quality of life. The manufacturer of this device and experts in this field recommend that the minimum age for BAHA implant is five years old. Although there are challenges associated with the implantation of BAHA in children, the overall outcomes are comparable to those of adults, and the benefits of BAHA, such as improved speech development, outweigh the disadvantages. - Screening according to strict eligibility criteria, preoperative counselling, close monitoring by a physician with BAHA expertise, and ongoing follow-up were identified as critical factors for long-term implant survival.

Authors' recommendations: - Level 4 evidence showed that the BAHA is safe; exit site infection and loss of fixture are the most common complications. - Improved hearing ability can be achieved for a small subset of patients with conduction or mixed hearing loss that cannot undergo surgical repair or wear a conventional bone conduction hearing aid. - For those with chronic discharging middle ear infection or congenital conduction hearing loss, the BAHA is likely the only available alternative to the conventional bone conduction hearing aid, and would improve hearing without aggravating the ear infection. - Given the nature of this technology, the indications for its use, and absence of alternative technologies for the target population, it is highly unlikely that Level 1 or 2 evidence will ever be forthcoming.

Authors' methods: Systematic review

Project Status: Completed

Year Published: 2002

URL for published report: http://www.health.gov.on.ca/english/providers/program/mas/tech/reviews/pdf/rev_baha_090102.pdf

URL for additional information: http://www.hqontario.ca/evidence/publications-and-ohtac-recommendations/ohtas-reports-and-ohtac-recommendations/bone-anchored-hearing-aid-baha

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Canada

Organisation Name: Medical Advisory Secretariat

Contact Address: Medical Advisory Secretariat, 20 Dundas Street West, 10th Floor, Toronto, ON M5G 2N6 CANADA. Tel: 416-314-1092l; Fax: 416-325-2364;

Contact Name: MASinfo.moh@ontario.ca

Contact Email: MASinfo.moh@ontario.ca

Copyright: Medical Advisory Secretariat, Ontario Ministry of Health and Long-Term Care