Superior Semicircular Canal Dehiscence Syndrome – Diagnosis and Surgical Management

Abstract

Introduction Superior semicircular canal dehiscence syndrome was described by Minor et al in 1998. It is a troublesome syndrome that results in vertigo and oscillopsia induced by loud sounds or changes in the pressure of the external auditory canal or middle ear. Patients may present with autophony, hyperacusis, pulsatile tinnitus and hearing loss. When symptoms are mild, they are usually managed conservatively, but surgical intervention may be needed for patients with debilitating symptoms. Objective The aim of this manuscript is to review the different surgical techniques used to repair the superior semicircular canal dehiscence. Data Sources PubMed and Ovid-SP databases. Data Synthesis The different approaches are described and discussed, as well as their limitations. We also review the advantages and disadvantages of the plugging, capping and resurfacing techniques to repair the dehiscence. Conclusions Each of the surgical approaches has advantages and disadvantages. The middle fossa approach gives a better view of the dehiscence, but comes with a higher morbidity than the transmastoid approach. Endoscopic assistance may be advantageous during the middle cranial fossa approach for better visualization. The plugging and capping techniques are associated with higher success rates than resurfacing, with no added risk of hearing loss.

Effectiveness of Transmastoid Plugging for Semicircular Canal Dehiscence Syndrome

“…Patients who experience SSCD syndrome typically experience sound- and/or pressure-induced vertigo, disequilibrium, autophony, hyperacusis, and aural fullness. 1-7 Clinically, patients often present with a low-frequency air-bone gap (ABG), decreased cervical vestibular evoked myogenic potential (VEMP) thresholds, and enhanced ocular VEMP amplitudes. 2,7 Computed tomography (CT) imaging of the temporal bone identifies absent or thinned bone overlying the superior canal, and this area of decreased cochlear input impedance provides the basis for the “third-window hypothesis,” in which clinical findings are explained by abnormal shunting of acoustic energy through the hypercompliant area of bony dehiscence.…”

The Gopen–Yang Superior Semicircular Canal Dehiscence Questionnaire: development and validation of a clinical questionnaire to assess subjective symptoms in patients undergoing surgical repair of superior semicircular canal dehiscence

“…dizziness and tinnitus). This observation underscores the need for patient-centred approaches like ours to provide robust, holistic characterisation of subjective symptomatology, particularly in the context of a condition such as superior semicircular canal dehiscence, which has only been defined and treated fairly recently 1 , 15 , 16 …”

“…The symptomatology of superior semicircular canal dehiscence is thus not adequately encapsulated in terms of auditory or vestibular symptoms alone, but must also incorporate the concomitant functional impairments, limitations to daily living, psychosocial components and impact on general quality of life (QoL) 14 . Although literature on the aetiology, diagnosis and treatment of superior semicircular canal dehiscence has greatly expanded in recent years, 3 , 15 , 16 thorough patient-centred assessment of superior semicircular canal dehiscence symptoms remains lacking.…”

The Forgotten Second Window: A Pictorial Review of Round Window Pathologies

“…Furthermore, the theoretic physiologic justification for this approach is lacking because occlusion of the round window should theoretically create preferential shunting toward the pathologic third window. 20,61,62 Cochlear Implant. Cochlear implants may be inserted through a cochleostomy adjacent to the round window or directly through the round window membrane.…”