Health

Dr. Lloyd Minor first described this condition in 1998. The inner ear has three semi-circular canals, each oriented in a different plane. These canals are all encased in the densest bone in the body, the otic capsule.

The semicircular canal that has the most vertical orientation, known as the superior semicircular canal, is occasionally incompletely encased. This leaves an opening into the canal (dehiscence)  that acts as an extra window. When this dehiscence is present it allows pressure and sound waves that enter the inner ear to dissipate through the extra window. This can cause the inner ear on the affected side to send a different signal to the brain than the inner ear on the normal side, which causes vertigo. It also allows sound vibration that enters the inner ear to dissipate, which may cause hearing loss. In this condition, loud noise and or pressure (i.e., pushing on the ear or straining for a bowel movement) cause vertigo. The vertigo stops once the pressure change stops. The diagnosis is confirmed with a CT scan.   Often times no treatment is necessary. Education on the condition and counseling are enough to allow the person to live with the condition. Some people, however, have very severe symptoms. These patients may be treated by plugging the opening in the affected canal. This is done through a craniotomy. Plugging is very effective, but it involves major surgery. The decision whether or not to treat is based on the severity of symptoms and the patient’s lifestyle.