Information for Parents
The Bone Bridge is a hearing aid system well suited to children with Microtia-Atresia who have a conductive hearing loss but with normal or near normal inner ear hearing. It can restore excellent quality hearing in some cases where an ordinary hearing aid or other corrective surgery is not suitable. It has two parts; internal and external.
The internal part, also known as a “receiver stimulator” is inserted during a short operation. It is placed under the skin and attached to the bone just behind where the ear would normally be positioned. It houses a magnet, which allows the external part to be held in place. The external part, also known as a “processor,” looks like a large button. It picks up sound signals and transmits these across the skin to the internal device, which converts these into sound vibrations, detected by the inner ear.
Various colour options for processors
Bone Bridge Position
Bone Bridge Position
Once in place, the internal part of the BoneBridge is expected to last indefinitely. The external part is worn during the day, and is removed at night and for swimming and bathing. Like other types of hearing aids, the external part of the BoneBridge is powered by batteries. These usually last 3-5 days, and the batteries are supplied by your audiologist.
The Bone Bridge is available free for children up to 18 years of age (and up to 21 years of age for those who remain in full time education) who are assessed by a specialist ENT surgeon and audiologist and who meet eligbility criteria. The external device costs $6,500 (in 2020), and after 18 years of age the child or family must cover the costs of any replacements and also batteries. Your or your child’s BoneBridge must be insured against loss, theft or breakage.
Assessment for suitability for BoneBridge
In general, the BoneBridge is the best available way to ensure normal or close to normal hearing in the affected ear/s.
For children who live out of the Auckland Area, Dr Brown can often consult via Facetime/What's App or Skype.
A hearing assessment is made by an audiologist (this can be your local audiologist) to determine whether the inner ear works sufficiently well to detect the sound vibrations made by the BoneBridge. Dr Brown would perform an examination and will request a CT scan of the ears to ensure that there is sufficient room to fit the internal part of the device. This may suit children as young as 4 years of age. The "Soundbridge" ( a very similar device but with a slightly more complex insertion) may suit even younger children, perhaps as young as two years of age.
The BoneBridge Operation
Dr Brown has the most experience of this device in New Zealand. Insertion of the internal part of the BoneBridge is performed during a 90-120 minute general anaesthetic (asleep), on a day stay basis. There is usually no need to stay in hospital overnight. A head bandage is worn overnight and removed the next morning by the parent. There is mild discomfort afterwards for a week. Sports and physical activities should be avoided for a month afterwards. A week off school is required.
Dr Brown and Dr Glenn Bartlett (the consultant Plastic Surgeon with by far the most experience in Microtia Surgery in NZ) have together performed pinna reconstruction in combination with BoneBridge implant surgery. This could suit older children who have been well aided until then by other means, such as a headband aid or "AdHear" device.
While the device is intended to function well for many years, and is durable and highly reliable,in a small percentage, the device may need to be replaced. There are also very small risks of infection around the internal device, which may have to be removed (and later replaced) if an infection occurs. There are also very small risks associated with the surgery including a very small risk of damage to the sigmoid sinus (a large vein within the bone) or to the dural lining around the brain.
Using the BoneBridge
The Bone Bridge may be used two weeks after the surgery to insert the internal part. An audiologist will program the external device to make the most of the sounds your child will be able to hear.
The external device has an adjustable magnet to ensure it stays on securely. In some circumstances, a specially designed bandana or head-band can be used for extra security for some sports.
Head protection (headgear) is recommended for those considering contact sports such as rugby and possibly also Netball. Water sports can begin again (without the external processor on) two weeks after the surgery. Some sunhats may need modification to enable use of the BoneBridge and a hat at the same time.
Airports- We suggest you advise security about the presence of a Bone Bridge implant, so that hand scanning can be done. The implant will not be harmed by going through airport security.
The BoneBridge has limited compatibility with MRI scanning (It can be safely used with the weaker magnet 1.5 T scanners, but not the stronger and generally newer 3 T scanners). It may sometimes need to be removed if an MRI scan of the brain is required in the future, although CT scans are still able to be done, and may suffice in many circumstances. I recommend that the child or adult with a Bone Bridge device, wear a medic alert bracelet in case of any accident in the future.