What is Superior Canal Dehiscence

Superior canal dehiscence(SCD) refers to an opening (dehiscence) in the bone that covers one of the semicircular canals of the inner ear. SCD most commonly occurs in the superior semicircular canal of the ear. SSD can result in symptoms that affect a person's balance and hearing.

What is Superior Canal Dehiscence Syndrome?

Superior canal dehiscence syndrome (SCDS) occurs due to an abnormal opening between the uppermost semicircular canal of the inner ear and the brain. Superior canal dehiscence syndrome causes problems with hearing and balance.

Superior canal dehiscence syndrome SCDS is a rare condition caused by an abnormal thinning of inner ear bone or incomplete closure of one of the bony canals in the inner ear.

What are the Causes of Superior Canal Dehiscence (SCD)?

• The actual cause of superior canal dehiscence syndrome is not known.
• The dehiscence may be congenital (present from birth) or may have occurred during the inner ear development.
• SCD can also be caused by certain infections as well as head trauma.
• Many believe that SCD is multifactorial. There may be a congenitally thin amount of bone, which is susceptible to trauma or infections or may become thin further with aging.

Symptoms of Superior Canal Dehiscence Syndrome

Oscillopsia (appearance of movement of stationary objects)

Vertigo – Dizziness

Autophony – Another disturbing symptom of SCDS is autophony ("hearing one's self"). Sounds from inside the body such as heartbeat, blood flow, breathing, or even slight movement of the eye's muscles may enter the inner ear directly through the abnormal third opening.

Sensitivity to loud sounds.

Fullness/pressure in the ears.

• SCDS can cause problems with balance and hearing, which can be either constant or intermittent.
• In SCDS, loud noise can cause a sensation that the world is tumbling or bobbing up and down. Coughing or sneezing can cause the same effect.
• When people with SCDS talk, they may hear their own voices simultaneously from outside and inside the body, which can be overwhelmingly loud. That is why many patients with SCDS resort to whispering.

Diagnosis of Superior Canal DEHISCENCE Syndrome

CT SCAN
CT SCAN can be helpful in the detection of SCDS, but CT SCAN may give a false impression of dehiscence when the bone is merely thin but intact. Therefore other diagnostic tests are advised.

HEARING TESTS
Hearing tests are critical for the proper diagnosis of SCDS, as is an exam by a neurotologist.

VESTIBULAR EVOKED MYOGENIC POTENTIAL
Vestibular-evoked myogenic potential (VEMP) uses sound generator tests reactions in neck muscles or eye muscles.

Treatment
The most common treatment options are:

• Resurfacing – or more commonly today, plugging of the dehiscence from the middle cranial fossa approach.
• Plugging of the dehiscence from the mastoid approach.
• Reinforcement of the round window membrane.

SURGERY-
Surgery to correct the dehiscence can bring relief for those who are debilitated by their symptoms.

PROCEDURE-
The surgeon creates an opening in the skull's middle cranial fossa to gain access to the inner ear.

The surgeon then plugs the superior canal to eliminate most of the fluid movement and resurfaces the superior canal.

Through this surgery, most patients do very well and find relief in their hearing and balance symptoms.