Articles © The authors | Journal compilation © J Clin Med Res and Elmer Press Inc™ | www.jocmr.orgThis is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited308Original ArticleJ Clin Med Res. 2015;7(5):308-314ress Elmer Common Features in Patients With Superior Canal Dehiscence Declining Surgical TreatmentLina Zahra Benamira a , Anastasios Maniakas a , Musaed Alzahrani a , Issam Saliba a, bAbstractBackground: Superior canal dehiscence (SCD) is a benign condition in which a surgical treatment may be considered depending on the patients’ tolerance of their symptoms. In this study, we aim to identify driving factors behind the patients’ choice of a surgical management over watchful waiting.Methods: Sixty-two patients with cochlear and/or vestibular symp-toms and a temporal bone high-resolution CT (HRCT) scan showing SCD were included in the study. All patients have been offered either surgical management or watchful waiting.Results: Of these, 28 elected surgery and 34 declined it. The oper-ated group showed more cochlear (6.6 vs. 2.4) symptoms than the non-operated group (P < 0.001) except for hypoacousis, but no sig-nificant difference (P = 0.059) was found for the number of vestibu-lar symptoms between both groups (3.4 vs. 1.1). Footstep and eating hyperacousis were both present in 57.1% of operated vs. 3% of non-operated patients (P < 0.001). Oscillopsia with effort and with walk-ing was found in 50% and 35.7% of operated patients, respectively, but none in the non-operated group (P < 0.001). Hearing tuning fork at malleolus and Valsalva and pneumatic speculum induced vertigo showed a statistically significant difference between the two groups (P = 0.003, P < 0.001, P = 0.010 respectively). Cervical vestibular-evoked myogenic potential (cVEMP) thresholds, air and bone con-duction thresholds, and mean air-bone gap (ABG) were similar in the two populations (P > 0.05). The average dehiscence size was 4.7 mm (2.0 - 8.0 mm) and 3.8 mm (1.3 - 7.7 mm) in the operated and non-operated patients, respectively (P = 0.421).Conclusions: The natures of cochleovestibular signs and symptoms were shown to be key factors in patients’ choice of a surgical man-agement whereas paraclinical tests seem to be less significant in the patients’ decision for a surgical treatment.Keywords: Superior canal; Dehiscence syndrome; Hyperacousis; Autophony; OcculophonyIntroductionIn 1998, Minor first reported a syndrome in which a dehis-cence of the bone overlying the superior semicircular canal (SSC) induces effects on both vestibular and auditory function. Creation of a “third mobile window” disturbing the endolym-phatic movement in the bony labyrinth appears to be the main pathophysiologic mechanism of superior canal dehiscence syndrome (SCDS). The most common vestibular manifesta-tions are sound- and/or pressure-induced vertigo and oscil-lopsia. As for auditory function, patients often show signs of conductive hyperacousis, defined as an increased sensitivity to bone conducted sounds. The latter manifests as autophony or unusual awareness of sounds such as one’s heel strike, heart-beat or even eye movements. Hearing loss generally completes the clinical presentation [1]. Diagnosis of SCDS relies on clin-ical findings, vestibular-evoked myogenic potential (VEMP) thresholds and radiologic findings of a defect in the bony roof overlying the SSC. Cervical VEMPs (cVEMP) are short-laten-cy inhibitory muscular responses to intense sound and vibra-tion stimulation. They are recorded over the ipsilateral sterno-cleidomastoid muscle while the latter is contracted [2]. The standard radiologic evaluation of patients suspected of having superior canal dehiscence (SCD) is a fine-cut (0.5- to 0.6-mm collimation) temporal bone high-resolution CT (HRCT) with the reconstruction of images parallel to the plane (Poschl’s view) of the SSC [3, 4]. The impact of SCD on the above diag-nostic tests has been widely studied. We know for instance that thresholds for eliciting cVEMP using air-conducted sounds are usually lowered in the symptomatic ear when compared with normal controls and appear to normalize on canal plugging [5-8]. Moreover, patients with a dehiscence equal to or larger than 3.0 mm consistently show an air-bone gap (ABG) on audio-metric tests [3, 6, 9-11].Even though the optimal approach has yet to be determined, the surgical management of SCD is mainly focused upon clos-ing the supernumerary “third mobile window” in the SSC. The Manuscript accepted for publication February 03, 2015a Montreal University Hospital Center (CHUM), University of Montreal, Mon-treal, Quebec, Canada b Corresponding Author: Issam Saliba, Division of Otolaryngology Head and Neck Surgery, CHUM, 1560 Sherbrooke Street East, Montreal, QC H2L 4M1, Canada. Email: issam.saliba@umontreal.ca doi: http://dx.doi.org/10.14740/jocmr2105w
