Electrocochleography in the diagnosis of third window conditions.

Introduction: Superior semicircular canal dehiscence (SSCD) is the best-known and most common presentation of so-called "third window conditions." There are a variety of diagnostic measures and tests for this condition in the current literature, including air-bone gap, vestibular-evoked myogenic potentials, and electrocochleography (EcochG). The purpose of this study was to investigate the diagnostic utility of EcochG and its relationship to air-bone gap in a cohort of patients with confirmed SSCD. Methods: We reviewed data from 20 patients (11 female and 9 male subjects, age ranging 21-78 years), with confirmed unilateral or bilateral superior canal dehiscence. In total, 11 patients had unilateral SSCD and 9 patients had bilateral SSCD as determined by high-resolution CT scan. This resulted in the inclusion of twenty-nine ears with superior canal dehiscence and 11 normal ears. Results: Our results indicated that all confirmed SSCD ears presented with an abnormal EcochG SP/AP value and that there was a statistically significant difference between normal and dehiscent ears. There was no statistically significant relationship between air-bone gap and SP/AP ratio in the ears diagnosed with SSCD nor was there a significant difference between dehiscent and normal ears in terms of air-bone gap at three frequencies. Discussion: These results are consistent with previous studies showing the diagnostic utility of EcochG for this condition and the variability of air-bone gap. While an unexpected air-bone gap continues to be a red flag for SSCD, its absence along with the presence of subjective symptoms is a reasonable indicator for further clinical investigation to include EcochG.

Sealing of superior semicircular canal dehiscence is associated with improved balance outcomes postoperatively versus plugging of the canal in middle fossa craniotomy repairs: a case series.

OBJECTIVE: The authors compared postoperative symptoms between patients with sealed and those with plugged semicircular canal dehiscence repairs. METHODS: In total, 136 ears from 118 patients who underwent surgical repair for semicircular canal dehiscence were identified via chart review. Data from postoperative MRI scans showing preservation or loss of semicircular canal fluid signal and postoperative reports of autophony, amplification, aural fullness, tinnitus, hyperacusis, hearing loss, vertigo, dizziness, disequilibrium, oscillopsia, and headache were amalgamated and analyzed. RESULTS: Patients with preservation of fluid signal were far less likely to have dizziness postoperatively (p = 0.007, OR 0.158, 95% CI 0.041-0.611). In addition, these patients were more likely to have tinnitus postoperatively (p = 0.028, OR 3.515, 95% CI 1.145-10.787). CONCLUSIONS: The authors found that superior semicircular canal dehiscence patients who undergo sealing without plugging have improved balance outcomes but show more tinnitus postoperatively than patients who undergo plugging.

Pediatric superior semicircular canal dehiscence: illustrative case and systematic review.

OBJECTIVE The purpose of this study is to present an illustrative case of pediatric superior semicircular canal dehiscence (SSCD) and to systematically review the current published literature in the pediatric population. METHODS An electronic search of the Scopus, Web of Science, PsycINFO, Cochrane, and Embase databases was performed by 2 independent authors through January 2017. Search term combinations included "pediatrics," "children," "canal," and "dehiscence." Inclusion criteria were as follows: English, full-text clinical studies, case reports, and case series describing pediatric patient(s) (younger than 18 years) with CT evidence of SSCD. Baseline patient demographic characteristics, clinical presentations, dehiscence characteristics, management strategies, and outcome data were extracted. RESULTS A total of 14 studies involving 122 patients were included in the quantitative synthesis. The patients' mean age was 7.22 years. Male predominance was observed (approximate male-to-female ratio of 1.65:1). Neurodevelopmental disorders were common (n = 14, 11.5%). Auditory signs and symptoms were more common than vestibular signs and symptoms. Hearing loss (n = 62, 50.8%) was the most common auditory symptom and an indicator for imaging evaluation. Vertigo was the most common vestibular symptom (n = 8, 6.6%). Hearing aids were recommended in 8 cases (6.6%), and surgical repair was performed in 1 case (0.8%). Symptom outcomes and follow-up durations were infrequently reported. CONCLUSIONS The authors' data suggest that in pediatric SSCD, males are more commonly affected than females. This is different than the adult population in which females are predominantly affected. A history of otologic and/or neurodevelopmental abnormalities was common. There was a preponderance of auditory symptoms in this age group. Conservative management was favored in the majority.

Superior semicircular canal dehiscence syndrome.

Superior semicircular canal dehiscence (SSCD) syndrome is an increasingly recognized cause of vestibular and/or auditory symptoms in both adults and children. These symptoms are believed to result from the presence of a pathological mobile "third window" into the labyrinth due to deficiency in the osseous shell, leading to inadvertent hydroacoustic transmissions through the cochlea and labyrinth. The most common bony defect of the superior canal is found over the arcuate eminence, with rare cases involving the posteromedial limb of the superior canal associated with the superior petrosal sinus. Operative intervention is indicated for intractable or debilitating symptoms that persist despite conservative management and vestibular sedation. Surgical repair can be accomplished by reconstruction or plugging of the bony defect or reinforcement of the round window through a variety of operative approaches. The authors review the etiology, pathophysiology, presentation, diagnosis, surgical options, and outcomes in the treatment of this entity, with a focus on potential pitfalls that may be encountered during clinical management.

Clinical outcomes of middle fossa craniotomy for superior semicircular canal dehiscence repair.

OBJECTIVE Superior semicircular canal dehiscence (SSCD) is a rare disorder characterized by the formation of a third opening in the inner ear between the superior semicircular canal and the middle cranial fossa. Aberrant communication through this opening causes a syndrome of hearing loss, pulsatile tinnitus, disequilibrium, and autophony. This study analyzed the clinical outcomes of a single-institution series of patients with SSCD undergoing surgical repair by the same otolaryngologist and neurosurgeon. METHODS All patients who underwent SSCD repair at the University of California, Los Angeles, between March 2011 and November 2014 were included. All patients had their SSCD repaired via middle fossa craniotomy by the same otolaryngologist and neurosurgeon. Outcomes were analyzed with Fisher's exact test. RESULTS A total of 18 patients with a mean age of 56.2 years (range 27-84 years) and an average follow-up of 5.0 months (range 0.2-21.8 months) underwent 21 cases of SSCD repair. Following treatment, all patients (100%) reported resolution in ≥ 1 symptom associated with SSCD. Autophony (p = 0.0005), tinnitus (p = 0.0059), and sound- and/or pressure-induced dizziness (p = 0.0437) showed significant symptomatic resolution. Following treatment, 29% (2/7) of patients developed imbalance, 20% (1/5) of patients developed sound- and/or pressure-induced dizziness, and 18% (2/11) of patients developed aural fullness. Among patients with improved symptoms following surgical repair, none reported recurrence of symptoms at subsequent follow-up visits. CONCLUSIONS SSCD remains an underdiagnosed and undertreated condition. Surgical repair of SSCD using a middle fossa craniotomy is associated with a high rate of symptom resolution. Continued investigation using a larger patient cohort and longer-term follow-up could further demonstrate the effectiveness of using middle fossa craniotomy for SSCD repair.