Superior semicircular canal dehiscence (SSCD) syndrome

Superior semicircular canal dehiscence (SSCD) syndrome is a rare condition that affects the inner ear. It occurs when there’s an abnormal opening (dehiscence) in one of the bony canals of the inner ear, specifically the superior semicircle canal.

Your inner ear has three semicircular canals; each has fluid that helps regulate your balance. An opening in the superior semicircle canal makes it difficult for your inner ear to control movement and balance. It may also allow sounds from your inner ear to reach your brain, causing sound distortion and hearing loss.

SSCD may also be referred to as superior canal dehiscence syndrome (SCDS). It affects approximately 1 to 2 percent of the general population. Although it may be present from birth, most people don’t experience symptoms until later in life.

At Penn Medicine Otology and Neurotology, our specialists are experts at diagnosing and treating uncommon conditions like SSCD. We work with physical therapists trained in vestibular rehabilitation, audiologists, and other providers to create an individualized treatment plan.

Some people with superior semicircular canal dehiscence don’t immediately have symptoms. When symptoms do show up, they can mimic other ear disorders, making the condition difficult to diagnose.

SSCD symptoms may include:

• A feeling of fullness or pressure in the ear
• Autophony (perceiving your voice as too loud or echoing in your ears)
• Hearing loss
• Hyperacusis (hypersensitivity to sound)
• Oscillopsia (when it looks like stationary objects are moving)
• Pulsatile tinnitus (hearing sounds in time with your heartbeat)
• Tullio’s phenomenon (sound-induced vertigo)
• Vertigo (dizziness)

Experts don’t know the exact cause of SSCD, but they have several theories. Possible causes include:

• A pressure-altering event (such as scuba diving or flying)
• Benign or malignant tumors
• Bone-thinning as you age
• Congenital disorder (present from birth)
• Head trauma

Some of these causes may go hand-in-hand. For example, you may have thinning bones that are more vulnerable to trauma.

First, your doctor will ask for a history of your symptoms to see if they align with SSCD. Next, they may order testing to diagnose SSCD, such as a computed tomography (CT) scan, vestibular evoked myogenic potential (VEMP) test, or a hearing evaluation.

If your symptoms are mild to moderate, you may be able to manage your SSCD by working with a certified vestibular physical therapist. They can show you ways to improve your balance and decrease your fall risk. It may also help to avoid loud environments and activities that worsen your symptoms.

If you’re debilitated by your symptoms, surgery to correct the dehiscence may provide relief. There are several approaches to surgery, including:

• Plugging the dehiscence: Your surgeon creates an opening in either your skull (middle cranial fossa approach) or behind your ear (transmastoid approach) to plug the opening. This eases symptoms by getting rid of most of the fluid movement. Our head and neck surgeons typically work alongside neurosurgeons to perform this procedure.
• Resurfacing the canal: Less common than plugging, this technique covers the opening without totally closing it.
• Round window reinforcement: This is the least invasive procedure, but symptoms can return afterward. A surgeon covers the opening using tissue from behind the ear.