Superior Canal Dehiscence: Case 1

Timothy C. Hain, MD   • Return to Main SCD page. • Page last modified: April 12, 2021

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This is an unusual SCD case. Most SCD patients do NOT have as many testing abnormalities as documented here. Most just have a high VEMP on one or both sides.

Case:

A 75 year old man developed dizziness. Audiometry revealed a mixed hearing loss on the left side. This is rare in SCD patients, as most have normal hearing. However, if they do develop hearing loss, a conductive pattern is likely. This has to do with bone being better than air conduction.

An ENG showed reduction in caloric testing on the left. This is rare in SCD patients. There is no reason that SCD should reduce the caloric response, as the canals are all still working.

VEMP testing showed an enlarged VEMP on the left.

CT scan of the temporal bone showed clear SCD on the left side.

This CT showing a pure coronal is not an optimal sequence to see SCD, as one has to flip through several images, to be sure there is no bone on this image and one in front and behind. A combination of the Stenver and Poschel is much better, but many radiology departments are not aware of this and don't do it.

 

Overall, one wonders if this patient had another inner ear problem, and the SCD was discovered serendipitously.