What is a BAHA?
The BAHA system consists of 3 parts.
1. The titanium implant which is a tiny screw (of either 3mm or 4mm depth).
4mm replica implant beside a 1p coin.
2. The Abutment, which is the socket that is attached to the implant, and sits on the surface of the scalp behind the ear.
3. The detachable Sound Processor (BAHA).
A BAHA (Bone Anchored Hearing Aid) is a sound processor. Its job is to convert sound waves from the surrounding air into vibrations.
The vibrations are carried via the implant and the skull to the functioning inner ear/s (cochlea), where they are converted into nerve stimuli and carried on the auditory nerve (hearing nerve) to the brain.
The brain then makes sense of the stimuli and we “hear”.
To benefit from the BAHA a person needs sufficient function in at least one cochlea. The only way to know if a person can benefit is for them to have a thorough assessment by an audiologist and ENT team who fit the BAHA.
The Implant Procedure.
The “two stages” of the procedure will be mentioned here. Though for most adults the two stage process is done in one procedure. Most children currently go through the two stage procedure.
Children will have a general anaesthetic for each stage. Adults can have a local anaesthetic, and the surgery can be done as a day case. A member of staff will be allocated to hand hold and ensure clear communication between the surgeon and the patient. The two stage procedure together takes approximately 40 minutes.
A local anaesthetic is administered. This can be “uncomfortable” but most people report that it isn’t “too painful”.
An area of skin is lifted from behind the ear where the BAHA is to be placed. The area will be approximately the size of a £2 coin, or the equivalent size but rectangle. (There are two types of graft lifting methods currently used).
The skin that is to be the graft is treated to remove hair follicles, so that when it is returned no hair will grow closely round the abutment. This is to prevent problems caused by hair getting caught under the abutment setting up infections, and to help with keeping the abutment site clean.
While the graft is lifted a tiny hole is drilled to prepare the place where the implant will be. This is very noisy, but very short lived. There is no pain, as bone does not have nerves in it. Some pressure will be felt as the surgeon works.
The final “drilling” noise will be the placement of the implant. *The abutment may already be attached to the implant, or the abutment will then be attached by the surgeon. The graft has a tiny hole made to accommodate the abutment, so that it passes over the abutment, and is then stitched in place.
The abutment would not be attached to the implant at this point. The graft would be placed completely over the implant and be stitched in place; a pressure dressing (mastoid bandage) would be bandaged over the site. 2nd. Stage - The abutment will be attached approximately 4 months after implant, a tiny hole made over the implant first, the dressing mentioned in the next paragraph will then be used (the sound processor is then fitted approximately 2 weeks after that).
Single procedure continued.
A disc, called the Healing Disc, is snapped on to the abutment. This keeps a dressing in place under it. A square of gauze is placed over the healing disc, over that a wad of cotton wool. All of this is bandaged securely and firmly (mastoid bandage). This is to prevent swelling of the graft area. The bandage, cotton wool and gauze can be removed (usually at home by the patient) 24 hours after the implant surgery.
But the Healing Disc and dressing under it MUST be left in place. The healing disc, dressing and stitches are removed two weeks after the implant.
The implant needs to be left undisturbed for three months after surgery. This is to enable the bone to bond securely with the implant. This process is highly successful as titanium is accepted by the bone, and is not treated as a foreign object by the body.
(The surgeons should advise when you can get the abutment site wet, and when you can begin to clean it yourself. Do ask them, if they do not mention this).
After three months (in adults) the sound processor is fitted. It can be removed and attached at will, as one would when using any other hearing aid.