Superior Semicircular Canal Syndrome Research Articles

Literature study: Superior semicircular canal syndrome (SSCS)

Superior Semicircular Canal Syndrome (SSCS) or Superior Canal Dehiscence Syndrome is a rare abnormality in the medical field in the form of balance disturbance or vertigo caused by loud noises or changes in pressure causing rupture of the roof of the superior semicircular canal. SSCS was first described by Lloyd Minor in 1998 after more than 70 years since Tullio and Hennebert discovered the Tullio phenomenon, a condition in which vertigo or nystagmus is triggered by loud noises, and the Hennebert phenomenon, a condition in which vertigo or nystagmus, is triggered by changes in pressure. The exact prevalence of superior semicircular canal syndrome is not known until now. Estimates of prevalence varied from 0.5–2% of cases in temporal bone studies, to 3–9% of cases in studies performed with CT scans. Cases of SSCS are more common in males than females. Clinical symptoms that appear in SSCS are caused by dehiscence so that patients will complain of autophonia, which the sound produced by their body sounds louder, hyperacusis, tinnitus, vertigo which is triggered by loud noises, and nystagmus. A Careful history, an examination of hearing and balance function, also high-resolution CT scan are needed to establish the diagnose of SSCS. Management can be done conservatively. If the complaints are severe, then operative options can be considered.

‘Soft reinforcement’ of the round window for superior semi-circular canal dehiscence syndrome

Individuals with superior semi-circular canal syndrome often describe vestibular symptoms elicited by loud sounds, as well as other pressure-induced symptoms. They also often report other symptoms, including autophony, hyperacusis, cognitive dysfunction, spatial disorientation, anxiety and migraine headaches. Symptoms occur due to the presence of a 'third window' created by the dehiscence of the superior semi-circular canal. This case report describes a minimally invasive technique to provide soft reinforcement of the round window. Our patient underwent a permeatal procedure whereby the tympanic membrane was raised to allow inspection of the middle ear. The round window niche was identified and the round window membrane was reinforced with fat. The mucosa of the bony meatus leading to the round window was then disrupted before the application of a double layer of perichondrium to allow further reinforcement. The case provides support for the use of 'soft reinforcement' as a simple and effective technique to treat the symptoms of superior canal dehiscence syndrome.

Treatment of Menière’s Disease

Diagnosis of Menière's disease is made with a characteristic patient history, including discrete episodes of vertigo lasting 20min or longer, accompanied by sensorineural hearing loss, which is typically low frequency at first, aural fullness, and tinnitus. Workup includes audiometry, a contrast enhanced MRI of the internal auditory canals, and exclusion of other diseases that can produce similar symptoms, like otosyphilis, autoimmune inner ear disease, perilymphatic fistula, superior semicircular canal syndrome, Lyme disease, multiple sclerosis, vestibular paroxysmia, and temporal bone tumors. A history of migraine should be sought as well because of a high rate of co-occurrence (Rauch, Otolaryngol Clin North Am 43:1011-1017, 2010). Treatment begins with conservative measures, including low salt diet, avoidance of stress and caffeine, and sleep hygiene. Medical therapy with a diuretic is the usual next step. If that fails to control symptoms, then the options of intratympanic (IT) steroids and betahistine are discussed. Next tier treatments include the Meniett device and endolymphatic sac surgery, but the efficacy of both is controversial. If the above measures fail to provide symptomatic control of vertigo, then ablative therapies like intratympanic gentamicin are considered. Rarely, vestibular nerve section or labyrinthectomy is considered for a patient with severe symptoms who does not show a reduction in vestibular function with gentamicin. Benzodiazepines and anti-emetics are used for symptomatic control during vertigo episodes. Rehabilitative options for unilateral vestibular weakness include physical therapy and for unilateral hearing loss include conventional hearing aids, contralateral routing of sound (CROS) and osseointegrated hearing aids.

Subjective and objective findings in patients with true dehiscence versus thin bone over the superior semicircular canal.

To compare subjective and objective findings between patients with true dehiscence versus thin bone over the superior semicircular canal (SSC). Retrospective case series. Tertiary referral center. All patients from our institution with true dehiscence or thin bone over the SSC on computed tomography temporal bone (oblique view) from 2007 to 2013. Subjective test: Dizziness Handicap Inventory (DHI). Objective tests: Infrared video eye recording with varying stimuli (Tulio, Fistula, and Vibration); vestibular evoked myogenic potential (VEMP); electrocochleography; videonystagmography; pure-tone audiometry (i.e., air-bone gap). Fifty-four patients (64 ears) were reviewed. Thirty-nine patients (47 ears) had true dehiscence of the SSC on temporal bone computed tomography. Fifteen patients (17 ears) had thin bone over the SSC. There was no statistical difference in DHI scores for patients with true dehiscence versus those with thin bone over the SSC. Only cervical VEMP and air-bone gap via pure-tone audiometry revealed a significant difference between the two groups. The remaining vestibular assessments did not demonstrate any difference. No significant correlations were revealed between DHI and objective test findings across and within the two groups. Among the objective tests, cervical VEMP and pure-tone audiometry are the only tools to distinguish between true dehiscence and thin bone over the SSC. DHI does not differentiate between these two groups. Furthermore, no correlation exists between DHI and any objective finding. Further investigation is necessary to develop a validated subjective symptom index of patients with SSC syndrome.

Re: Superior semicircular canal syndrome should be searching for an alternative pathology

Re: Superior semicircular canal syndrome should be searching for an alternative pathology

Superior semicircular canal syndrome should be searching for an alternative pathology

Clin. Otolaryngol. 2012, 37, 298–299

Efficacy assessment and complications of surgical management for superior semicircular canal dehiscence: a meta-analysis of published interventional studies

Superior semicircular canal syndrome (SSCS) includes vestibular and audiological symptoms which result from the introduction of a third mobile window into the osseous cochlea. Surgical repair is considered in cases of incapacitating symptoms. The present paper aims at comparing the different surgical approaches and modes of dehiscence repair, regarding their respective efficacy and potential pitfalls. A systematic literature review and meta-analysis of pooled data were performed. Study selection included prospective- and retrospective-controlled studies, prospective- and retrospective-cohort studies, ex vivo studies, animal models, case-reports, systematic reviews and clinical guidelines. A total of 64 primary operations for SSC repair were identified; 56 ears were operated for vestibular and 7 for auditory complaints. A total of 33 ears underwent canal plugging, 16 resurfacing, and 15 capping. Success rates were 32/33, 8/16, and 14/15, respectively. The observed differences were statistically significant (P=0.001). Resurfacing proved less effective than both plugging (P=0.002), and capping (P=0.01) techniques. Temporalis fascia was commonly used as sealing material and was combined with bone-pâté/bone-wax (plugging), bone-graft (resurfacing), or hydroxyapatite-cement (capping). Most operations were performed via middle-fossa approach; higher success rates were associated with plugging and capping techniques. SNHL and disequilibrium were the most frequent complications encountered. Most cases were followed for 3-6 months. Precise criteria regarding follow-up duration and objective success measures are not determined. Surgical repair of SSCS is considered as a valid therapeutic option for patients with debilitating symptoms. Consensus regarding strict follow-up criteria and objective assessment of success is necessary before larger scale operations can be implemented in clinical practice.