Superior Semicircular Canal Dehiscence

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Superior Semicircular Canal Dehiscence is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Superior semicircular canal dehiscence (SSCD) has been defined as the absence of bone overlying the superior semicircular canal facing toward the dura of the middle cranial fossa. SSCD has been implicated as the cause of a variety of inner ear symptoms including Tullio's phenomenon, pressure induced vertigo, aural fullness, autophony, conductive hearing loss, and fluctuating or progressive sensorineural hearing loss. Additionally, SSCD has also been reported to be asymptomatic. In the past, many patients with SSCD had been misdiagnosed as having otosclerosis, patulous eustachian tubes, middle ear perilymphatic fistulas, or Ménière's disease. Identification of this entity requires a high degree of suspicion, appropriate findings on physical exam, lab testing, and confirmation on high-resolution CT scan. Surgical repair of the SSCD or occlusion of the superior canal has been reported with a high degree of symptom resolution.

Supporting Organizations

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311

Vestibular Disorders Association (VEDA)

5018 NE 15th Ave
Portland, OR 97211
Tel: (503)229-7705
Fax: (503)229-8064
Tel: (800)837-8428

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

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Last Updated:  3/7/2016
Copyright  2016 National Organization for Rare Disorders, Inc.