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Ossicular Chain Discontinuity

Ossicular Chain Discontinuity

Sound vibrations are collected by the outer portion of the ear and funneled down the ear canal towards the eardrum. The sounds are then transmitted through three tiny bones in the middle ear called the ossicles. These three bones are named the malleus, incus and stapes. The stapes carries the sound vibration into the fluids of the inner ear, called the cochlea.

If the bones of the middle ear do not carry the sound to the inner ear correctly, hearing loss results. This can happen if the bones are not connected together properly (either fused together or separated). One cause of this problem is a disease called otosclerosis. Also, trauma or infection can lead to problems with the middle ear bones, called ossicular chain discontinuity. Some children are born with malformed middle ear bones that don’t conduct sound properly.

Ossicular chain discontinuity, or separation of the middle ear bones, most commonly happens when chronic ear infections dissolve the delicate middle ear bones. However, it may also happen with a skull fracture or after penetrating trauma, such as a Q-tip injury. The most common type of problem is separation of the joint connecting the incus to the stapes. The second most common is separation of the joint connecting the malleus to the incus. Fracture of the arch stapes may also occur.

Hearing loss is the most frequent symptom. The loss may appear very gradually. Many people first notice that they cannot hear low-pitched sounds or that they can no longer hear a whisper. In addition to hearing loss, some people may experience tinnitus. Tinnitus is a sensation of ringing, roaring, buzzing or hissing in the ears or head that accompanies many forms of hearing loss.

Management strategies include observation, hearing aids or surgery.

Keck Medicine of USC is the University of Southern California’s medical enterprise, one of only two university-owned academic medical centers in the Los Angeles area.