Bone-anchored hearing aid

Overview

Bone-anchored hearing aids (BAHA), also known as bone-anchored hearing implants (BAI), are medical devices designed to assist individuals with specific types of hearing loss or those unable to use traditional hearing aids. Unlike traditional hearing aids that amplify sound through the middle ear, BAHA devices work by transmitting sound vibrations through the bones of the skull directly to the inner ear, bypassing the middle ear.

Types

BAHA systems consist of three main components: a titanium implant, an external connector, and a sound processor.

Bone conducting hearing systems has two main types:

• Surgically implantable bone-anchored hearing aids (BAHA): The procedure typically involves placing a titanium implant in the bone behind the ear and attaching an external sound processor after it heals. This type of implant allows the processor to be removed for sleeping, showering, or hair treatments.
• Nonsurgical bone conduction hearing aids (BCHA): BCHA devices can be attached to the skin with adhesive or worn on a headband. This is often recommended for people who prefer not to have surgery and for children under 5.

The suitable option for an individual is determined based on one’s age, medical history, type of hearing loss, and personal preferences. During a consultation, one can try a nonsurgical BCHA to understand how it works before opting for surgery.

Reasons for undergoing the procedure

To determine eligibility for a BAHA, a specialized healthcare provider will conduct an evaluation. People with the following conditions may benefit from BAHA:

• Single-sided deafness: This is a condition where one ear has normal hearing while the other ear has little to no hearing.
• Conductive or mixed hearing loss: This condition is a result of sound waves not passing through the ears properly.

BAHA may be prescribed for hearing loss caused by conditions such as aural atresia, Ménière’s disease, acoustic neuroma, cholesteatoma, or chronic middle ear infections.

Risks

Although BAHA is a minimally invasive surgical procedure, it still poses some risk, just like any surgery. Potential risks include:

• Implant failure, which occurs when the implant and the bone do not merge correctly
• Infection
• Inflammation

Bone-anchored hearing aids (BAHA) can have severe effects if a person using bone-anchored hearing aids experiences head trauma, such as a hit to the head. To minimize this risk, it is advised to wear a helmet during contact sports or while biking or riding a motorcycle.

Procedure

The procedure begins with administering anesthesia to ensure comfort, using either local or general anesthesia as appropriate. It then proceeds as follows:

• Creating a small incision behind the ear, followed by creating a small hole in the mastoid bone, which is part of the skull
• A tiny titanium implant, approximately three to four millimeters in diameter—similar to half the size of a pea—will be carefully positioned in the hole
• An abutment, serving as a connector to the implant, will be attached, allowing the skin to heal around it, protruding slightly
• The incision will be closed with stitches and covered with surgical dressing

Bone-anchored hearing aids work through osseointegration, where the bone fuses with a titanium implant for stability. This fusion, which allows attachment to the sound processor, typically takes one to three months, depending on the type of BAHA and one’s healing capacity. The procedure itself usually lasts 30 to 60 minutes.

Outcome

Generally, BAHA provide several benefits, such as:

• Enhanced comfort: This offers a more comfortable fit and reduces the risk of skin irritation, since there is no need for insertion into the ear canal unlike conventional hearing aids.
• Improved outcome predictability: Trying a non-surgical bone-anchored hearing aid during an office visit with the healthcare provider allows for better anticipation of post-surgery results.
• Superior sound quality: The bone-conducting signal remains unaffected by the skin, resulting in improved auditory clarity.

After a BAHA implantation, the initial recovery period typically lasts between three to seven days. However, patients cannot use the hearing aid immediately because the bone needs time to fuse with the titanium implant. This fusion process usually takes several weeks. Once the fusion is complete, the healthcare provider will attach the external sound processor and adjust its settings to optimize the patient’s hearing. Patients will also receive instructions on the proper removal and reattachment of the processor.

Soreness and redness near the implant site is often common in few days after the recovery. However, it is important to take note of the potential complications, such as:

• A fever higher than 38.3 degrees Celsius
• Swelling, discharge, or infection at the implant location
• Medication fails to make ear pain go away