Current Trends, Controversies, and Future Directions in the Evaluation and Management of Superior Canal Dehiscence Syndrome.

Kristine Elisabeth Eberhard,Daniel J Lee,Hideko Heidi Nakajima,Divya A Chari,Mads Klokker,Per Cayé-Thomasen

doi:10.3389/fneur.2021.638574

Abstract

Patients with superior canal dehiscence syndrome (SCDS) can present with a range of auditory and/or vestibular signs and symptoms that are associated with a bony defect of the superior semicircular canal (SSC). Over the past two decades, advances in diagnostic techniques have raised the awareness of SCDS and treatment approaches have been refined to improve patient outcomes. However, a number of challenges remain. First, there is currently no standardized clinical testing algorithm for quantifying the effects of superior canal dehiscence (SCD). SCDS mimics a number of common otologic disorders and established metrics such as supranormal bone conduction thresholds and vestibular evoked myogenic potential (VEMP) measurements; although useful in certain cases, have diagnostic limitations. Second, while high-resolution computed tomography (CT) is the gold standard for the detection of SCD, a bony defect does not always result in signs and symptoms. Third, even when SCD repair is indicated, there is a lack of consensus about nomenclature to describe the SCD, ideal surgical approach, specific repair techniques, and type of materials used. Finally, there is no established algorithm in evaluation of SCDS patients who fail primary repair and may be candidates for revision surgery. Herein, we will discuss both contemporary and emerging diagnostic approaches for patients with SCDS and highlight challenges and controversies in the management of this unique patient cohort.

Highlights

Superior semicircular canal dehiscence syndrome (SCDS) was first reported by Minor et al in 1998 [1]
The priorities of the clinical treatment team are to: [1] confirm that both ears with superior canal dehiscence (SCD) are associated with localizing signs and symptoms and supporting findings on audiometric and vestibular evoked myogenic potential (VEMP) testing [44, 78]; [2] determine if there is a “worse” ear [44, 78]; [3] rule out co-morbid factors such as migraines that can prolong recovery if surgery is offered, as bilateral SCD itself prolongs recovery; [4] discuss that bilateral superior canal dehiscence syndrome (SCDS) is associated with a lower rate of complete symptom resolution [108]; and [5] communicate the concerns that bilateral sequential repair could be associated with chronic balance impairment, as patients who undergo surgery bilaterally are at higher risk of vestibular hypofunction [45, 79]
SCD has been increasingly recognized as a treatable cause of vestibular and auditory dysfunction

Summary

Introduction

Superior semicircular canal dehiscence syndrome (SCDS) was first reported by Minor et al in 1998 [1]. Because SCD is a mechanical pathology affecting the acoustics of the inner ear, WAI may serve an important role in the evaluation of patients with residual signs and symptoms following primary SCD repair.

Results

Conclusion