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 and a small implanted 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.
Parts of Bone-Anchored Implant Systems
The bone-anchored implant system is comprised of three parts -- a titanium fixture, a connecting abutment, and a detachable sound processor. 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, usually performed under local or "twilight" anesthesia, the titanium fixture is placed in the mastoid bone behind the ear.
How Many Bone-Anchored Implant Systems are Available?
There are currently two companies that make the bone-anchored implants. The BP 100 (now called the Baha 3) is made by the Cochlear Corporation and the Ponto Pro is made by Oticon Medical.
 |
 |
| BP 100 (Now called the Baha 3) Bone-Anchored Implant System | Ponto Pro Bone-Anchored Hearing System |
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 aggrevation of chronic ear drainage)
- Otosclerosis in an only hearing ear
- Single-sided deafness, regardless of the cause of hearing loss
For patients with Single-Sided Deafness AND a hearing loss in the opposite ear, a more powerful bone-anchored hearing device is recommended. The following table is summary of the Cochlear Corporation and Oticon Medical power options:
|
BAHA 3 Power |
Ponto Pro Power |
Manufacturer |
Cochlear Americas |
Oticon Medical |
Fitting Range |
Up to 55dBHL |
Up to 55dBHL |
Number of Channels |
12 |
15 |
Number of Memories |
3 |
4 |
Feedback Cancellation |
Yes |
Yes |
Noise Reduction |
Yes |
Yes |
Multiband Adaptive Directionality |
Yes |
Yes |
Bone Conduction Measurement available in software |
Yes |
Yes |
Tamper-Resistant Battery Door Available |
Yes |
Yes |
T-coil Available |
Yes |
Yes |
FM Compatible |
Yes |
Yes |
Controls on Processor |
Program Button and Volume Buttons |
Program Button and Volume Wheel |
Battery Size |
675 Disposable |
675 Disposable |
Weight |
19 grams with battery |
17 grams without battery |
Dimensions |
36x22x12mm |
34x21x11mm |
Warranty |
2 years |
2 years |
|
Baha 3 Power |
Ponto Pro Power |
Manufacturer |
Cochlear Americas |
Oticon Medical |
Fitting Range |
Up to 55 dB HL |
Up to 55 dB HL |
Number of Channels |
12 |
15 |
Number of Memories |
3 |
4 |
Feedback Cancellation |
Yes |
Yes |
Noise Reduction |
Yes |
Yes |
Multiband Adaptive Directionality |
Yes |
Yes |
Bone Conduction Measurement Available in Software |
Yes |
Yes |
Tamper-Resistant Battery Door Available |
Yes |
Yes |
T-Coil Available |
Yes |
Yes |
FM Compatible |
Yes |
Yes |
Controls on Processor |
Program Button and Volume Buttons |
Program Button and Volume Wheel |
Battery Size |
675 Disposable |
675 Disposable |
Weight |
19 grams with battery |
17 grams without battery |
