Bone-Anchored Hearing Implants

What are Bone-Anchored Hearing implants?

Bone-anchored hearing implants are not hearing aids. Instead, bone-anchored implant systems are a combination of a sound processor (worn behind the ear), a small connecting abutment (that comes through the skin) and a small titanium fixture implanted in the bone behind the ear. The system allows sound to be conducted through the bone of the skull directly to the inner ear (cochlea) rather than through the middle ear -- a process known as direct bone conduction. No component of bone-anchored implants fit inside the ear or ear canal. The bone-anchored hearing systems are approved by the Food and Drug Administration (FDA) as class II devices.

Ponto Power System

Oticon Medical Ponto 3 Power Bone-Anchored Implant System (1 = Sound processor. 2 = Abutment. 3 = Fixture) (Photo courtesy Oticon Medical)

Parts of Bone-Anchored Implant Systems

The bone-anchored implant system is comprised of three parts -- a detachable sound processor (#1 above), a connecting abutment (#2 above), and a titanium fixture (#3 above). Unlike hearing aids, the bone-anchored systems includes an implant -- the titanium fixture -- that osseointegrates (i.e. grows into bone) with living tissue to form a permanent, functional bond with the bone of the skull. During a minor outpatient surgical procedure, the titanium fixture is placed in the mastoid bone behind the ear.

Ponto sound processor side view

Side view of Ponto sound processor attached to abutment. (Photo courtesy Oticon Medical)

How Many Bone-Anchored Implant Systems are Available?

There are currently two companies that make the bone-anchored implants. The Baha 5® is made by the Cochlear Corporation and the Ponto Pro is made by Oticon Medical.

How Does the Bone-Anchored Implant Work?

1. A sound processor picks up sound vibrations.

2. The sound processor is attached to an abutment, which sits above the skin. The abutment transfers the sound vibrations from the processor to the titanium implant in the bone.

3. Since the small titanium implant is fused with the bone of the skull, the implant transfers the sound vibrations to the functioning inner ear (cochlea).

Who Can Benefit From a Bone-Anchored Implant?

Bone-anchored implants are approved for anyone over the age 5 years old for the the treatment of conductive or mixed hearing loss, as well as for unilateral sensorineural hearing loss, also known as Single Sided Deafness (SSD).

Prior to bone-anchored implants, patients with SSD had only one available treatment -- the CROS (contralateral routing of signal) hearing aid, a treatment with limited performance due to its placement inside the only functioning ear. For those with SSD, the bone-anchored implant gives patients the opportunity to perceive hearing as if the sound were coming from the deaf side.

For those under age five years old, there is a specially designed headband that holds the bone-anchored sound processor. The headband uses an adjustable elastic band to hold the sound processor comfortably against the skin without the abutment and fixture.

Examples of Specific Conditions Helped by Bone-Anchored Implants

  • Congenital absence of the ear canal (microtia)
  • Chronic ear drainage from outer or middle ear infection (since the bone-anchored device does not block the outer ear canal, as is true for hearing aids, which may be a cause for aggravation of chronic ear drainage)
  • Otosclerosis in an only hearing ear
  • Single-sided deafness, regardless of the cause of hearing loss