[Dehiscence syndromes : Diagnosis and treatment]

Dehiscence syndromes of the semicircular canals are a relatively new group of neurotological disorders. They have a variety of symptoms with hearing/balance involvement. Younger patients have clinically relevant symptoms in only about one third of cases. In addition to etiology and pathogenesis, the present paper describes diagnostic and therapeutic possibilities using a patient series of the authors.

This nonrandomized prospective study included 52 patients with uni-/bilateral dehiscence syndromes of the superior and/or posterior canal (SCDS/PCDS), diagnosed with high-resolution computed tomography (HR-CT) of the petrous bone. Of 41 patients undergoing surgical therapy for severe symptoms-predominantly vertigo attacks (Meniere-like) and/or falls (Tumarkin crises)-31 received single-sided hearing implants.

Of the 41 patients with transmastoid superior and/or posterior canal occlusion, 30 showed a significant improvement of balance in the Dizziness Handicap Inventory (DHI); the dizzy spells ceased. A positive outcome was correlated with the severity of the preoperative disorder; a poor outcome (nonsignificant increase in DHI, recurrent vertigo of various qualities/frequencies) with the comorbidities vestibular migraine, Menière's disease of the contralateral ear, and a dehiscence size exceeding 4 mm.

The more severe the vestibular symptoms, the better the outcome of surgical therapy. Auditory symptoms (nonspecific aural fullness, hyperacusis) do not generally respond well to surgical therapy. Cochlear implants have an additional beneficial effect; comorbidities should be considered as (relative) contraindications.