Superior Canal Dehiscence Syndrome (SCDS)

Superior canal dehiscence syndrome, also called superior semicircular canal dehiscence syndrome, is caused by an abnormal connection or bone that is extremely thin between your brain and your inner ear’s superior semicircular canal. This fluid-filled tube helps control balance. Instead of fluid traveling normally through a closed canal, it can escape through the abnormal opening. This can cause unusual hearing and balance symptoms, including:

• Autophony, which means hearing your own voice loudly or in a distorted way or hearing your own body sounds like breathing, eyeball or eyelid movements, footsteps, gastric noises, or a thumping that sounds like your heartbeat (called pulsatile tinnitus)
• Dizziness that is triggered by loud noises and/or sneezing, coughing, straining, or other activities that affect your inner ear pressure
• A constant feeling of ear pressure or ear fullness
• Oscillopsia, which refers to unstable vision that makes you feel like your surroundings are moving back and forth
• Nystagmus, which means uncontrolled, repetitive eye movements

Vestibular Migraines
Vestibular migraines are severe headaches that cause dizziness and are easily triggered by light and sound. Vestibular migraines and superior canal dehiscence syndrome have similar symptoms, and it is common to have both. Superior canal dehiscence syndrome can also worsen or trigger vestibular migraines.

Superior canal dehiscence syndrome is often misdiagnosed. That’s why it’s important to seek care at a center like Duke, where a team of experts led by a neurotologist will evaluate your inner ear function and discuss your symptoms and medical history. They will consider imaging and test results as well as your own experiences when confirming the diagnosis. Your doctor may recommend the following tests:
 
CT Scan
A computed tomography (CT) scan uses advanced X-ray technology to create detailed images of bony structures inside your ear. 

Hearing Test (Audiogram)
Audiologists measure how well you hear sounds and plot the results on a graph called an audiogram. Experienced audiologists who specialize in vestibular problems test whether you can hear bone-conducted sounds better than normal, a hallmark feature of this disorder. Your ear doctor might ask the audiologist to play loud sounds to test whether your eyes move in a certain direction, another telltale sign of superior canal dehiscence syndrome. 

Vestibular Evoked Myogenic Potential (VEMP)
This test assesses the integrity of the inner ear structures and nerves and whether there is an abnormal connection between your inner ear and brain. Audiologists stimulate the inner ear with sound and measure the response in your eye or neck muscles using electromyography, which records muscle electrical activity through electrodes attached to the skin.

Eye Movement Tests
A special pair of lighted goggles magnify your eyes, making eye movements easier to detect and helping reveal other causes of dizziness.

Migraine Treatment
If you also experience vestibular migraines, your doctor will probably recommend a migraine treatment plan first. This may include diet changes, avoiding migraine triggers, supplements, and medications. If your symptoms do not improve, surgery may be recommended.

Canal Dehiscence Repair Surgery – Two Approaches
Superior semicircular canal dehiscence repair surgery aims to plug or resurface the open superior canal. Surgeons use your own tissue and bone along with surgical cement and glue to close the hole and restore normal function. Your doctors will recommend one of two surgical approaches based on your anatomy, age, other medical conditions, and preferences. Both approaches use small incisions that heal quickly and leave minimal scarring. 

• Transmastoid Approach: Surgeons access the canal through the mastoid bone behind your ear. This technique does not require surgeons to pull back the delicate lining of the brain (the dura). Some people may be able to return home the day of their surgery.
• Middle Fossa Craniotomy: Surgeons access the superior canal by making a small hole in the skull, just above the ear. This technique gives surgeons a better view of the superior canal and easier access to repair other areas of missing bone, which are common in people with superior canal dehiscence. 

Vestibular Physical Therapy
It’s important to complete vestibular physical therapy after undergoing surgery for superior canal dehiscence. Duke physical therapists will teach you exercises to help improve your balance and adjust to your new inner ear anatomy.

Leading Skull Base Center
People come from North Carolina, the Southeast, and beyond to be treated at Duke for rare, complex conditions like superior canal dehiscence that are located near the bottom of the skull, which is called the skull base. Although these conditions are rare, we treat them routinely.

Experts Trained by Leaders in the Field
Several of our neurotologists were trained by the experts who discovered superior canal dehiscence syndrome, and at the institution where the surgical repair was invented and perfected. Duke surgeons collaborate with colleagues at other leading institutions about highly complex cases. 

Committed to Guidelines-Based Care
Rather than jump to a superior canal dehiscence syndrome diagnosis or immediately recommend surgery, our experts follow consensus guidelines from the Bárány Society, an international organization involved in vestibular research. Because we select the right patients for the right treatments, you are more likely to have the best outcomes.