Superior Semicircular Canal Dehiscence Syndrome

1. A D E W I J A Y A , M D – M A Y 2 0 2 0
Superior Semicircular Canal Dehiscence Syndrome

2. Outline
 Introduction
 Pathophysiology
 Clinical presentation
 Diagnostic Criteria
 Differential Diagnosis
 Treatment
 Summary

3. Introduction
 Chronic disequilibrium and sound- or pressure-
induced vertigo and nystagmus in the plane of the
superior semicircular canal.
 Introduced in the last 2 decades.
Minor LB, Solomon D, Zinreich JS, Zee DS. Sound- and/or pressure-induced vertigo due to bone dehiscence of the superior semicircular canal. Arch Otolaryngol Head Neck
Surg (1998) 124:249–58

4. Pathophysiology

5. Clinical Presentation
 Dizziness
 Vertigo
 Sound- and/or pressure-induced vertigo (Tullio Phenomenon /
Hennerbert Sign)
 Autophony
 Hearing loss
 Aural pressure
 Nonpulsatile tinnitus
 Pulsatile tinnitus
 Hyperacusis
 Oscillopsia
 Positional vertigo
 Drop attacks
 Motion sickness
 Imbalance
Rosowski JJ, Songer JE, Nakajima HH, Brinsko KM, Merchant SN. Clinical, experimental, and theoretical investigations of the effect of superior semicircular canal dehiscence on
hearing mechanisms. Otol Neurotol 2004;25(03):323–332
Minor LB. Clinical manifestations of superior semicircular canal dehiscence. Laryngoscope 2005;115(10):1717–1727
Merchant SN, Rosowski JJ,McKenna MJ. Superior semicircular canal dehiscence mimicking otosclerotic hearing loss. Adv Otorhinolaryngol 2007;65:137–145

6. Diagnostic Criteria
Ward BK, Carey JP, Minor LB. Superior canal dehiscence syndrome: lessons from the first 20 years. Front Neurol 2017;8:177

7. Differential Diagnosis
 Posterior and horizontal canal dehiscence
 Perilymphatic fistula
 Near dehiscence
 Vestibular migraine
Steenerson KK, Crane BT, Minor LB. Superior Semicircular Canal Dehiscence Syndrome. InSeminars in Neurology 2020 Jan 27. Thieme Medical Publishers.

8. Treatment
 Avoidance of the environmental factors that can
produce symptoms (such as loud noises)
 Surgery

9. Summary
 Uncommon but treatable cause of vestibulocochlear
symptoms.
 Differential diagnosis of all patients presenting with
either episodic or chronic dizziness, particularly in
those with auditory symptoms as well.
 A mobile “third window”
 Multidisciplinary approach

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