The Supine Superior Semicircular Canal Dehiscence Test

Purpose The purpose of this clinical focus article is to describe a new method for assessment of superior semicircular canal dehiscence by laying the patient supine during Valsalva-induced nystagmus testing. Method The traditional Valsalva-induced nystagmus test is described, followed by a new method for assessment of superior semicircular dehiscence conducted by laying the patient supine during testing. A case study is presented to illustrate this new testing technique known as the Supine Superior Semicircular Canal Dehiscence Test. Results It is hypothesized that during Valsalva-induced nystagmus testing performed in the upright, seated position, the dura mater could potentially seal the superior semicircular canal fistula, thereby concealing a defect in the bony labyrinth and yielding a false-negative test. To circumvent this, the patient should be placed in the supine position during Valsalva-induced nystagmus testing in order to prevent the dura mater from inadvertently sealing itself against the petrous portion of the temporal bone. The Supine Superior Semicircular Canal Dehiscence Test may reveal the defect in the bony labyrinth and improve the sensitivity of the Valsalva-induced nystagmus test. Conclusions The Supine Superior Semicircular Canal Dehiscence Test may be more sensitive for identifying superior semicircular canal dehiscence in patients with traditional symptoms and a negative Valsalva-induced nystagmus test in the seated position. While a case study is presented to illustrate the potential benefits of including the Supine Superior Semicircular Canal Dehiscence Test in the battery of diagnostic tests, further research is needed in larger samples.

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A Third Labyrinthine Window: An Overview of Perilymph and Labyrinthine Fistulae and Superior Semicircular Canal Dehiscence

Otorhinolaryngology Clinics - An International Journal ◽

10.5005/jp-journals-10003-1094 ◽

2012 ◽

Vol 4 (2) ◽

pp. 100-105 ◽

Cited By ~ 2

Keyword(s):

Inner Ear ◽

Semicircular Canal ◽

Membranous Labyrinth ◽

Superior Semicircular Canal Dehiscence ◽

Bony Labyrinth ◽

Superior Semicircular Canal ◽

Inner Ear Fluids ◽

Canal Dehiscence

ABSTRACT The membranous labyrinth is contained within the bony labyrinth and surrounded by perilymph. The only two ‘potentially yielding’ parts of the otherwise solid bony labyrinth are the oval and round windows, which by their relative movements, pressure differentials and resilience are responsible for all the functions attributed to the inner ear. In pathologies, such as trauma, infection or occasionally congenital dehiscence, there may develop a ‘third window’ that may serve as an abnormal communication for the inner ear fluids and manifest with audiovestibular symptoms. Three such distinct entities have been identified, namely ‘superior semicircular canal dehiscence syndrome, perilymphatic fistulae and labyrinthine fistulae’. This overview intends to discuss these above-mentioned entities, as regards their characteristic presentations and principles of management. How to cite this article Hathiram BT, Khattar VS. A Third Labyrinthine Window: An Overview of Perilymph and Labyrinthine Fistulae and Superior Semicircular Canal Dehiscence. Otorhinolaryngol Clin Int J 2012;4(2):100-105.

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Complete round Window Niche Occlusion for Superior Semicircular Canal Dehiscence Syndrome: A Minimally Invasive Approach

Ear Nose & Throat Journal ◽

10.1177/014556130908800808 ◽

2009 ◽

Vol 88 (8) ◽

pp. 1042-1056 ◽

Cited By ~ 24

Author(s):

Herbert Silverstein ◽

Mark J. Van Ess

Keyword(s):

Semicircular Canal ◽

Round Window ◽

Surgical Techniques ◽

Invasive Approach ◽

Superior Semicircular Canal Dehiscence ◽

Superior Semicircular Canal ◽

Auditory Dysfunction ◽

Round Window Niche ◽

Canal Dehiscence

Superior semicircular canal dehiscence (SCD) syndrome is a recognized condition associated with varying degrees of vestibular and auditory dysfunction. The authors present a case study of disabling SCD syndrome in a 37-year-old man who was successfully treated with a complete round window niche occlusion via a transcanal approach. This case represents the first report of a transcanal complete round window niche occlusion for the treatment of SCD syndrome. A brief literature review and discussion of surgical techniques follow.

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