Superior Canal Dehiscence

There are many possible causes for dizziness. If your doctor feels that the problem lies in your inner ear, it may be what is known as a superior canal dehiscence. This could mean:

• The membranes of the inner ear may have worn down to bone
• There may be a problem with the bones themselves

The bones of the ear canal can wear down over time. Excessive pressure or continual rhythmic pulsations, or throbbing, can cause this deterioration. When the bones are thin, a new pathway is opened up that allows fluid to travel to and collect in the inner ear. This is what triggers the dizziness and other symptoms associated with this condition. Increased intracranial pressure may also cause this to happen.

Dizziness or vertigo, which is a sense of being off-balance, are usually the first symptoms you will notice. Heavy lifting, coughing, and sneezing may also cause a loss of visual focus that lasts for a few seconds. Other symptoms may include:

• Autophony, or hearing yourself when you speak
• Hearing loss
• A sensation of having a blocked ear canal that doesn’t fade when you pop it
• Ability to hear internal sounds in your ears, such as your heartbeat

A CT scan should be performed if a superior canal dehiscence is suspected. A vestibular evoked myogenic potential test can also be performed. This test transmits sound waves as tension through a neck muscle. This can help determine how the structures of the inner ear are functioning. Your physician may also watch your eye movements to analyze any abnormal function there.

Environmental changes are generally the first option for treatment. This would include avoiding loud sounds and other triggers such as lifting heavy object. Self-treatment may not be effective in eliminating all the symptoms, however. Surgery is the next option for treatment.

Middle Fossa Approach: This is the most common surgical treatment for superior canal dehiscence. To access the ear canal, the surgeon will enter the skull right above the ear. The affected canal can then be plugged up with fibrous tissue and secured by bone chips.

Transmastoid Approach: In this surgery, the canal is accessed from behind the ear. This process also involves blocking or plugging the canal to prevent fluid from flowing into the inner ear.

Round Window Plugging: In this surgery, the inner ear is accessed directly through the ear canal, so there is no drilling through the skull. The same concept of plugging up the area is employed.