ABSTRACT
Bone-anchored hearing aids (BAHA) exploit the principle of bone conduction hearing, in which sound energy can be transmitted directly to the inner ear via bones of the skull. Bone conduction hearing bypasses the outer and middle ear, circumventing anatomical or pathological problems in these areas. BAHAs use titanium implants, surgically inserted into the skull. The bone around the implant forms a closely-knit interface, a process known as osseointegration. The commonest indication for BAHA is active chronic suppurative otitis media, in which patients with conductive or mixed hearing loss are unable to wear air-conduction hearing aids due to exacerbation of infections. BAHA implantation can be undertaken under general or local anaesthesia. The commonest complication of directly coupled BAHAs is local soft tissue reaction around the percutaneous abutment. Magnetically coupled and active BAHAs do not have any skin penetrating components and thus complications are less. Local skin pressure may lead to discomfort requiring reduction in magnet strength or temporary cessation in use.
