Implantable acoustic devices (IADs)

Like conventional hearing aids, IADs stimulate the hearing organ in response to sounds. However, instead of transmitting sound through the ear canal, IADs transmit sounds as vibrations through the skull and middle ear bones to the inner ear.

IADs may also be called BCIs (bone conduction implants) or BAHAs (bone anchored hearing aids).

IADs are usually suggested for people who:

• Can’t use conventional hearing aids because their ear canal or the outside parts of the ear haven’t developed.
• Have a certain type and level of hearing loss.

There are four types of IADs available at GOSH:

Percutaneous BCI:

An abutment (a small metal connector) is attached to the skull and comes through the skin. The abutment can be connected to a sound processor which sits on the outside of the head. The sound processor looks like a small box and vibrates to send the sound signal through the abutment and skull to the inner ear.

Magnet BCI/ Passive transcutaneous BCI:
A magnet about the size and shape of a two pence coin is implanted under the skin. A sound processor sits on the outside of the head. They are held together by magnetic attraction. The sound processor sends vibrations through the skin to the internal magnet and then to the skull and the inner ear.

Active transcutaneous BCI:

This also sits completely under the skin. However, unlike the abutment and magnet BCI, the implant (the internal part) produces the vibrations rather than the sound processor (the external part). An external sound processor is held in place using a weak magnet and tells the internal implant what sounds to produce.

Middle ear implant (MEI):

This works similarly to an active transcutaneous BCI, however it sends sounds directly to the inner ear via the bones in the middle ear, rather than the skull.

Your child’s Audiologist and Ear Nose and Throat (ENT) surgeon will discuss suitable options with you. Your child may not be suitable for all types of implant.

Please note: the following lists are not exhaustive but provide an overview.

We will look at your child’s hearing tests and the condition of their hearing. A CT scan may also be recommended.

We will also often recommend trialing a bone conduction hearing aid secured with a head band for a few weeks. This can give us an indication of whether your child will benefit from an IAD.

Depending on your child’s age, the soft band may also be a temporary measure until they are old enough for the operation.

• If the trial is successful, the Audiologist will make an appointment for you to see the ENT surgeon to discuss the options.
• If the trial is not successful, an IAD will not be the best option for your child so other treatments may be discussed.

Your child’s ENT surgeon will discuss the surgery with you both in a clinic appointment and on the day of surgery. They will answer any questions and ask you to give permission for the operation by signing a consent form.

The operation will be carried out while your child is under general anaesthetic (they will be asleep). An anaesthetist will talk you through this on the day of surgery.

All surgery and anaesthesia carries a degree of risk but we will do everything we can to minimise it.

The risk of the anaesthetic will depend on your child’s medical condition(s). Risks cannot be removed completely but modern equipment, training and medicines have continued to make anaesthesia safer. An anaesthetist will be with your child throughout their anaesthetic to monitor their progress and to help them to wake up as comfortably as possible.

There is a risk of bleeding and possible infection with any operation. Blood loss during surgery is usually minimal and we may give your child antibiotics to reduce the risk of infection. If implants become infected, they may need to be removed to allow the body to heal, before they are reinserted at a later date.

The implants may occasionally become loose from the skull bone - this is often connected to an infection in the area.

Middle ear implants are more complex operations and therefore have greater risks. Specifically, there are very small chances of causing a hearing loss in the inner ear and of injuring the nerve that moves the face.

There is also a risk that your child may not find adequate hearing benefit from the auditory implant.

If your child is recovering well from the surgery and anaesthetic, they will be able to go home later on the day of surgery or the following day.

We may give your child a course of antibiotics to reduce the risk of infection. Please complete the course of antibiotics even if your child is feeling better.

For some children the surgical site will still be a bit swollen and uncomfortable when they get home. Carry on giving your child paracetamol and/or ibuprofen pain relief according to the instructions on the bottle or packet.

Keep the wound clean and dry for the first 10 days after the operation. After this, take care when hair washing or brushing.

The sticky paper stitches will fall off in a few days - the other stitches are dissolvable so will not need to be removed.

Your child should not go swimming or take part in sports or PE lessons until they have seen the ENT surgeon at their follow-up appointment.

If your child had a percutaneous BCI inserted, there will be a dressing under the healing cap. Do not remove this until the ENT appointment one week after the operation - at this appointment the dressing may be replaced.

Signs of infection include:

• Your child is in a lot of pain and pain relief does not seem to help.
• Your child has a temperature of 38°C or higher.
• The operation site is red or inflamed and feels hotter than the surrounding skin.
• There is an unpleasant smell or ooze from the operation site.

If you see any signs of infection, take your child to the nearest Accident and Emergency (A&E) department immediately, or to a GP if they are able to be seen urgently (on the same day).

During office hours, you can also ring the ENT secretaries on 020 7813 8220 to arrange a review or to get advice from a member of the ENT team.

We will make a follow up appointment with the ENT surgeon a few weeks after the operation.

An audiology appointment will be booked for approximately one to three months after the operation, depending on which surgery your child has.

Once the wound has healed, the hearing processor will be fitted and reprogrammed. This may be the same processor that was fitted on the soft band in the trial.

Whilst you’re waiting for this fitting, your ENT surgeon can advise whether your child should continue using the soft band. Do not attempt to put the soft band processor onto the implant as this may damage the integration.

The fitting appointment will involve either reprogramming your child’s existing device to work well with their new implant, or providing a new processor. When using a magnet fixture, the audiologist may need to trial different strengths to find out which one is most suitable for your child. The magnet needs to be strong enough to stay on but not too tight that it will cause complications.

Once your child has been using the hearing device for a few weeks, the Audiologist will continue to assess your child's hearing with the BCI and arrange appropriate follow ups.

Email: audiology.info@gosh.nhs.uk

Phone: 020 7813 8315

Or message us directly through the MyGOSH app.

Read more about contacting the audiology department.