What is a Bone-Anchored Implant?
A Bone-Anchored Implant, or Baha, is surgically implanted. It is usually used for less severe hearing losses that are conductive, mixed, or unilateral. Bahas work by transmitting sound through the bone.A Baha is not to be confused with a cochlear implant. Unlike a cochlear implant, the Baha is implanted behind the ear instead of in the ear. The Baha has three parts:
- An implanted titanium part (screw) surgically implanted behind the ear.
- A button-like holder (abutment) screwed into the implanted titanium part. This abutment is visible.
- An external sound processor (the hearing aid).
Although it is also sometimes referred to as a bone-anchored hearing aid, a Baha is considered a prosthesis because it "replaces" a function, making it eligible for Medicare coverage. According to the Medicare Benefit Policy Manual, payable prosthetic devices include "Osseointegrated implants, i.e., devices implanted in the skull that replace the function of the middle ear and provide mechanical energy to the cochlea via a mechanical transducer."
Candidates for Bone-Anchored Implants
Typical Baha candidates can not use regular hearing aids. They may have malformed ears due to conditions such as Treacher Collins Syndrome, microtia, or atresia, persistent ear infections, otosclerosis, or even serious otitis media. Children whose skulls are thick enough, and adults can both use Bahas.Makers of Bone-Anchored Implants
Cochlear corporation bought Entific (www.entific.com), the previous maker of the Baha.Bone-Anchored Implant Community
Yahoo Groups has the discussion list BAHA_PPL. Another list is the AtresiaMicrotia list.Websites About Bone-Anchored Implants
There is an illustrated page on Bahas on the University of Maryland Medical Center website.Research and Articles on Bone-Anchored Implants
The Baha is a relatively recent development, in use only since 1977. Articles have been published and clinical research done into Baha:Articles
These are some of the available articles, in reverse chronological order:
- "Taking the Ear Out of the Equation" is an article from Hearing Health, volume 20, number 3, Fall 2004.
- "Bone-anchored hearing aids: current status in adults and children," and "The bone-anchored hearing aid: a solution for prevously unresolved otologic problems" - articles in Implantable electronic otologic devices : state of the art, the theme of Otolaryngologic clinics of North America, v. 34, no. 2, a series published in 2001.
- "Semi-implantable Bone-anchored Hearing Aid for Patients with Sensorineural Hearing Loss" is the title of a presentation at the Second Biennial Hearing Aid Research and Development Conference, September 22-24, 1997, , National Institutes of Health, Bethesda, Maryland.
- Developments in research and technology: "Implantable hearing aids." Hearing Loss , Volume 22(1) , Pgs. 34-35. This 2001 article discusses Bahas.
- "Update on implants: Bone-anchored devices and middle ear implants." The Hearing Journal, July 1, 1999.
"Efficacy of the Bone-Anchored Hearing Aid for Unilateral Deafness" is the subject of a clinical trial conducted by The New York Eye & Ear Infirmary. Details available through clinicaltrials.gov (NCT00201617). Study examining effectiveness of the Baha in adults with unilateral hearing loss.
