Semicircular Canal Dehiscence Syndrome Research Articles

Insights from therapeutic strategies in superior canal dehiscence syndrome: is there anything beyond surgical treatment?

Superior semicircular canal dehiscence syndrome (SCDS) is a clinical syndrome that can cause instability, vertigo, fullness, tinnitus, autophony, hearing loss (HL), Tullio phenomenon, or Hennebert's sign. Historically, surgery has been the primary treatment reported in the literature, although some medical treatments may also be proposed. This study aims to comprehensively characterize SCDS in a large series of patients from clinical, auditory, and vestibular perspectives, and explore medical alternatives to conventional surgical treatments by comparing their results and evolution. A retrospective observational study was designed in a tertiary care center. Audiovestibular tests evaluated included pure-tone audiometry (PTA), VEMPs, video head impulse test (vHIT), and CT imaging. Improvement was assessed over a follow-up period of up to 6 months for seven cardinal symptoms to verify the efficacy of the proposed treatments. 71 subjects with SCDS and a mean age of 51.20 ± 12.22 years were included in the study. The most common symptom found in our sample was instability in 31 patients (43.66%), followed by aural fullness or tinnitus in 29 subjects (40.85%). 36 patients (43.66%) received medical treatment, with 28 of them (77.78%) showing symptom reduction. Surgical repair was indicated in five patients, with all showing symptom improvement. Statistically significant improvement (p < 0.05) was observed, particularly with surgical treatment and acetazolamide, in both symptoms and objective tests such as pure-tone audiometry and VEMPs. SCDS shows significant similarities with other otic capsule dehiscences. It is essential to perform VEMPs and CT scans to complete the diagnosis, which is usually accompanied by clearly recognizable clinical criteria. Surgery for SCDS is effective, safe, and without complications. However, in cases where symptoms are mild to moderate, addressing this condition with medical treatment using diuretics such as acetazolamide has shown promising results.

What is known about superior semicircular canal dehiscence syndrome

Introdução: A origem da síndrome foi levantada através do estudo de tomografias computadorizadas onde os sintomas eram acompanhados de falha na cobertura óssea do canal semicircular superior, na fossa craniana média, próximo à dura-máter. Essa doença ainda não é de conhecimento da maioria dos médicos. Objetivo: Atualizar o conhecimento sobre ela para despertar a possibilidade de sua existência durante atendimento médico. Método: Revisão narrativa feita nas plataformas Pubmed e Scielo visando artigos ao tema, incluindo relatos de casos, estudos, revisões e metanálises publicados entre 1998 e 2023. Foram incluídos artigos em inglês, português e espanhol. Os descritores usados foram “superior canal dehiscence syndrome”, “superior canal dehiscence” e “síndrome da deiscência do canal semicircular superior”. Resultado: Foram analisados 47 artigos. Conclusão: O entendimento dessa síndrome é complexo e pouco conhecido, e aprimoramento das estratégias de tratamento requerem abordagem multidisciplinar com investigação contínua na intenção de oferecer melhor qualidade de vida ao portador. Tentativas evolutivas na orientação terapêutica até que se tenha confirmação por evidências de qual é melhor forma de tratamento, é o que na atualidade deve ser feito.

Role of Vestibular Rehabilitation in Patients with Superior Semicircular Canal Dehiscence Syndrome

Superior canal dehiscence syndrome (SCDS) described in 1998 is a disorder characterized by vertigo in response to loud sounds, pulsatile tinnitus, conductive hyperacusis, autophony and chronic disequilibrium. While resurfacing and/or plugging of the superior canal may improve autophony and reduce dizziness handicap, it can result in immediate and long-term deficits in VOR function, necessitating vestibular rehabilitation (VR) during the early post-operative recovery period. Case description: a 34- year-old man with a history of autophony, pulsatile tinnitus and audible eye movements in his right ear. He denied any vertigo or disequilibrium. Immediately after surgical plugging he presented severe vertigo and disequilibrium as well as deterioration of right hearing loss. Due to persistent instability, VR was performed for five months after surgery with improved outcomes. Our purpose is to emphasize and increase awareness in surgeons, especially in Latin America, the importance of VR immediately after surgery. Additionally, we make some comments about the surgical decisions in two patients with otosclerosis and SCDS and the importance of VR.

Practicality of multilayer round window reinforcement in the surgical management of superior semicircular canal dehiscence syndrome: a case report of long-term follow-up.

Several surgical techniques have been documented for approaching and repairing superior semicircular canal dehiscence syndrome (SCDS). These techniques encompass the trans-middle cranial fossa, transmastoid, endoscopic approaches, and round window reinforcement (RWR). RWR entails the placement of connective tissue with or without cartilage and around the round window niche, restricting the round window's movement to minimize the 3rd window effect and restore the bony labyrinth closer to its normal state. We employed the multilayer RWR technique, resulting in significant postoperative improvement and long-lasting effects for 3.7 years in 2 cases. Here, we present the clinical findings, surgical procedures, and the effectiveness of multilayer RWR. This technique can be the initial choice for surgical treatments of SCDS due to its high effectiveness, longer-lasting effect, and minimal risk of surgical complications.

Hearing Results after Transmastoid Superior Semicircular Canal Plugging for Superior Semicircular Canal Dehiscence: A Meta-Analysis.

The transmastoid plugging of a superior semicircular canal is considered a safe and effective technique for the management of superior semicircular canal dehiscence (SSCD). The aim of this meta-analysis is to assess the postoperative hearing outcomes after the transmastoid plugging of the superior semicircular canal. Search method and data sources: A systematic database search was performed on the following databases until 30 January 2023: MEDLINE, Embase, Cochrane Library, Web of Science, CINAHL, ICTRP, and clinicaltrials.gov. A systematic literature review and meta-analysis of the pooled data were conducted. We also included a consecutive case series with SCDS for those who underwent transmastoid plugging treatment at our clinic. We identified 643 citations and examined 358 full abstracts and 88 full manuscripts. A total of 16 studies were eligible for the systematic review and 11 studies for the meta-analysis. Furthermore, 159 ears (152 patients) were included. The postoperative mean air conduction threshold remained unchanged (mean difference, 2.89 dB; 95% CI: -0.05, 5.84 dB, p = 0.58), while the mean bone conduction threshold was significantly worse (mean difference, -3.53 dB; 95% CI, -6.1, -0.95 dB, p = 0.9). The transmastoid plugging technique for superior semicircular canal dehiscence syndrome, although minimally worsening the inner ear threshold, is a safe procedure in terms of hearing preservation and satisfactory symptom relief.

An evidenced-based diagnostic tool for superior semicircular canal dehiscence syndrome

PurposeTo construct a symptoms-based prediction tool to assess the likelihood of superior canal dehiscence (SSCD) on high-resolution CT. Materials and methodsMathematical modeling was employed to predict radiologic evidence of SSCD at a tertiary neurotology referral center. ResultsA total of 168 patients were included, of which 118 had imaging-confirmed SSCD. On univariate analysis significant predictors of SSCD presence were: sound/pressure-induced vertigo (p = 0.006), disequilibrium (p = 0.008), hyperacusis (p = 0.008), and autophony (p = 0.034). Multivariate analysis enabled a 14-point symptom-weighted tool to be developed, wherein a score of ≥6 raised the suspicion of SSCD (≥70% likelihood of being present), R2 = 0.853. ConclusionsThe likelihood of SSCD on CT scan can be determined with a high degree of certainty based on symptoms recorded at presentation. Using the evidenced-based diagnostic tool validated herein, a score ≥6 with any symptom combination justifies ordering a CT scan.

Method of registration of vestibular myogenic evoked potentials in the diagnosis of diseases of the inner ear

The literature review is devoted to the practical application of the method of recording vestibular evoked myogenic potentials (VEMPs) in the diagnosis of the inner ear diseases: superior semicircular canal dehiscence syndrome, Meniere's disease, benign paroxysmal positional vertigo (BPPV), vestibular neuritis. Registration of VMEP is an electrophysiological research method that allows to assess objectively the functional state of the otolith receptors (sacculus and utriculus) and their pathways, which expands the diagnostic capabilities in diagnosis of the inner ear diseases.

Investigation of serum calcium and vitamin D levels in superior semicircular canal dehiscence syndrome: A case control study

ObjectiveIt remains unknown whether calcium metabolism has any effect on the clinical presentation of superior semicircular canal dehiscence (SSCD). Our aim was to analyse the adjusted calcium and vitamin D levels in SSCD patients compared to a control group. MethodsThis was a prospective case-control study performed in a tertiary referral center, university teaching hospital in the UK. It included all new patients with SSCD seen in a dedicated skull base clinic over a 5-year period (2015–2019) compared to a gender and age matched control group. The main outcome of the study was adjusted calcium and Vitamin D levels between the two groups. ResultsA total of 31 SSCD patients were recruited with a matched number of control patients. The mean Vitamin D level on the SSCD group was 44.8 nmoL/l (SD: 20.8) compared to 47.5 nmoL/l (SD: 27.4) on the control group (p = 0.702). Mean Adjusted calcium level was 2.34 mmoL/l (SD: 0.7) for SSCD compared to 2.41 mmoL/l (SD: 0.11) for controls (p = 0.01), being within normal limits for both the SSCD and the control group. ConclusionOur study did not identify a link between Vitamin D levels and presence of SSCD. Normal adjusted calcium values were found in both groups. Despite that a statistically significant lower calcium level was found in the SSCD group which could indicate that suboptimal levels of calcium may affect the micro-environment of the otic capsule at the SSC region.

중두개와 접근법을 통한 상반고리관 피열 증후군의 수술적 치료 1예

Superior semicircular canal dehiscence (SSCD) syndrome is a rare disease characterized by sound and pressure induced vertigo accompanying vertical-torsional nystagmus, caused by dehiscence or absence of a bone overlying the superior semicircular canal. Patients show various extent of symptoms related to hearing and balance impairment, according to the degrees of bony dehiscence of superior semicircular canal. The authors have experienced a 41-year-old male patient with the chief complaint of severe hyperacusis and dizziness. The patient was finally diagnosed as left SSCD, and the symtoms were successfully treated surgically by repairing SSCD via middle cranial fossa approach. We thus report a rare case of SSCD syndrome accompanying not only dizziness but also severe hyperacusis and successfully managed by surgical method via middle cranial fossa approach.

Etiopathogenesis behind Semicircular Canal Dehiscence Syndrome: Review Article

AbstractSemicircular canal dehiscence remains one of the rare and least touched chronic vestibular diseases worldwide. Even though microbial, congenital, and genetically determined, as well as mixed characteristics are known to be involved in the pathogenesis of superior semicircular canal dehiscence syndrome (SSCDS), many facets of the pathogenesis of semicircular canal dehiscence syndrome still need to be simplified. Management plan related to pathogenesis has not yet been established. The primary objective of this review is to present and evaluate the etiopathogenesis behind SSCDS. This study is a systematic narrative review. A PubMed search (1970–2022) was performed for studies on epidemiology and pathogenesis of SSCDS. All included articles were categorized according to level of evidence. Five hundred and sixty papers were identified, of which 25 were found to be relevant for this review. SSCDS is a multifactorial disease. There is still no consensus as to what the specific etiology is behind the syndrome. No convincing evidence is available for most associated factors and pathogenesis. Important objectives in research of SSCDS should be achieving consensus about the definition of SSCDS and gaining more in-depth knowledge of the pathogenesis of SSCDS, especially the role of congenital and acquired causes. There is still a need for further well-designed studies on the various etiopathogenesis and management of SSCDS.

Long-Term Outcomes of Round Window Reinforcement for Superior Semicircular Canal Dehiscence Syndrome.

To report long-term patient reported outcome measures (PROMs) after standardized round window rein-forcement (RWR) with thin cartilage and perichondrium for superior semicircular canal dehiscence syndrome (SSCDS). Cross-sectional survey in 2020 and retrospective longitudinal study of outcomes at 3 months, 1 year, and last follow-up after 28 consecutive RWRs. Endpoints were the last follow-up for PROMs and 1 year postoperatively for audiometry and cVEMP. At the last follow-up (mean 2.4 years postoperatively), improvement was reported for 19/28 ears (68%) in symptoms overall; for 17/27 ears (63%) in auditory symptoms, and for 12/24 (50%) in vestibular symptoms. Nine ears (32%) required further surgery. No major complications occurred. On the group level, postoperative improvement at 3 months declined significantly for auditory and vestibular symptoms over time, and stayed stable beyond 1 year. Improved ears had on average 2.9 years follow-up. Improvement correlated significantly with SSCD length, and was associated with contralateral dehiscence. Thirteen ears (46%) had another potential cause of vestibular symptoms. This group showed significantly less improvement. Audiometric test results did not predict PROMs. Since long-term outcomes do not compare with those reported for plugging and repair, RWR is not suggested as a first line intervention for SSCDS. Considering the stable rates of improvement on average 2.9 years postoperatively and the absence of major complications, RWR may be an alternative to plugging or repair in fragile patients who do not accept the risk of complications with more invasive surgery, and who accept that results may deteriorate over time.

Predictive Factors for Concurrent Tegmen Dehiscence in Superior Canal Dehiscence Syndrome.

To describe factors predictive of tegmen dehiscence in subjects with superior semicircular canal dehiscence syndrome (SCDS). Retrospective case series. Tertiary referral center. Subjects with SCDS who underwent middle fossa craniotomy (MFC) for plugging/resurfacing. Operative and radiographic findings of tegmen dehiscences, preoperative low frequency air-bone gaps (LF-ABGs), ocular vestibular evoked myogenic potential (oVEMP) amplitudes, size of superior semicircular canal dehiscence (SCD), and history of obesity or obstructive sleep apnea (OSA). One hundred thirty six patients (avg. age, 50.6 yr, 55.1% female) underwent MFC for repair of SCDS. Tegmen dehiscences were commonly found intraoperatively (tegmen tympani dehiscence [TTD] in 19.9% [11% with dural contact of ossicles], tegmen mastoideum dehiscence [TMD] in 28.7%). There were no differences in preoperative LF-ABGs and preoperative oVEMP amplitudes with respect to tegmen status. The sensitivity and specificity of computed tomography (CT) for predicting an intraoperatively confirmed TTD was 85 and 74%, respectively, and 44 and 79% for TMD. History of obesity and OSA did not differ between those with and without tegmen dehiscences. The presence of contralateral SCD and increasing cross-sectional area of SCD were both significantly associated with concurrent tegmen defects. Obesity, OSA, preoperative oVEMP, and LF-ABG do not differ between those with SCD alone and those with SCD and concurrent tegmen dehiscences. Likewise, CT scans have relatively low sensitivity for identifying tegmen dehiscences. The presence of concurrent tegmen defects is more common in subjects with larger SCD cross-sectional areas and contralateral SCD.

Hearing Outcomes of Transmastoid Plugging for Superior Canal Dehiscence Syndrome by Underwater Endoscopic Surgery: With Special Reference to Transient Bone Conduction Increase in Early Postoperative Period.

To investigate the influence on hearing of transmastoid plugging of the superior semicircular canal accompanied with membranous superior canal transection by underwater endoscopic ear surgery (UWEES) for the superior semicircular canal dehiscence syndrome. Retrospective case review. Tertiary referral center. Seven patients underwent plugging with membranous superior canal transection with UWEES from 2017 to 2019. Bone conduction (BC) thresholds (250, 500, 1000, 2000, 4000 Hz) were repetitively examined in early postoperative period. Subjective symptoms and pure-tone audiometry. Transient BC threshold increase was detected in all cases in early postoperative period and hearing levels were ameliorated in 1 to 2 months. The mean maximum BC threshold elevations (dB) during the early postoperative period (within 1 mo) and the postoperative stable hearing period (after 2 mo) were 18.6 and 2.9 at 250 Hz, 24.3 and 8.6 at 500 Hz, 26.4 and 8.6 at 1000 Hz, 28.6 and 7.1 at 2000 Hz, and 30.0 and 0.8 (except for scale-out cases) at 4000 Hz. respectively. The mean maximum BC thresholds in the early period were significantly elevated compared with those in the stable period at each frequency (p < 0.01). Hearing outcomes of transmastoid plugging with transection of the membranous superior canal by using UWEES were found favorable in a long-term follow-up. However, it caused transient reversible hearing loss in all cases. The BC increase in early postoperative period may not cause permanent hearing loss but improvement for the surgical technique may still be necessary.

Superior semicircular canal dehiscence syndrome.

Superior semicircular canal dehiscence syndrome is a condition with troubling ear symptoms and vertigo caused by a defect in the bone between the inner ear and the middle cranial fossa. The disease is not dangerous, and for many patients it is sufficient to provide a thorough explanation for the symptoms and advice about coping strategies, balance exercises and, if necessary, use of assisted hearing devices. Surgical treatment may be appropriate for patients with severe symptoms.

Superior semi-circular canal dehiscence syndrome: quantifying the effectiveness of treatment from the patient's perspective

Superior semi-circular canal dehiscence syndrome is a disorder characterised by auditory and vestibular symptoms that can significantly impact quality of life, and yet it has no disease-specific quality of life instrument. Thirty-six patients who underwent transmastoid superior semicircular canal resurfacing and plugging were included from an initial cohort of 60 surgically managed patients. A sub-cohort of 19 consecutive patients completed validated symptom and quality of life questionnaires before and after surgery. Of the 36 patients, 31 participated in a telephone semi-structured interview post-operatively. Following surgery, there was a statistically significant improvement in autophony index score (p = 0.02), symptom severity score (p < 0.001) and sound hypersensitivity (p = 0.01). Thematic analysis of telephone interviews suggested three main symptom themes: auditory hypersensitivity, dysequilibrium, headache and concentration difficulties. Dysequilibrium was found to persist post-operatively. Surgery improves overall symptoms and quality of life. However, important symptom themes may be overlooked using the outcome measures that are currently available. A unified disease-specific outcome measure is urgently required to better understand the impact of symptoms and measure treatment effects.

Post-traumatic peripheral vestibular disorders (excluding positional vertigo) in workers following head injury

Benign paroxysmal positional vertigo has typically been reported to be the most common cause of post-traumatic dizziness. There is however paucity in the literature about other peripheral vestibular disorders post-head injury. This article provides an overview of other causes of non-positional dizziness post-head trauma from our large institutional experience. The UHN WSIB Neurotology database (n = 4291) between 1998 and 2018 was retrospectively studied for those head-injured workers presenting with non-positional peripheral vestibular disorders. All subjects had a detailed neurotological history and examination and vestibular testing including video nystagmography, video head impulse testing (or a magnetic scleral search coil study), vestibular-evoked myogenic potentials, and audiometry. Imaging studies included routine brain and high-resolution temporal bone CT scans and/or brain MRI. Based on a database of 4291 head-injured workers with dizziness, 244 were diagnosed with non-positional peripheral vertigo. Recurrent vestibulopathy (RV) was the most common cause of non-positional post-traumatic vertigo. The incidence of Meniere’s disease in the post-traumatic setting did not appear greater than found in the general population. The clinical spectrum pertaining to recurrent vestibulopathy, Meniere’s disease, delayed endolymphatic hydrops, drop attacks, superior semicircular canal dehiscence syndrome, and uncompensated peripheral vestibular loss are discussed.

Low accuracy of 1.5 Tesla magnetic resonance imaging in identification of the bony defect in patients with superior semi-circular canal dehiscence syndrome: case-control study.

To determine the accuracy of 1.5 Tesla magnetic resonance imaging in identifying the bony defect in superior semi-circular canal dehiscence syndrome. A retrospective case-control study was conducted in tertiary university settings. The study included 12 patients with a definite diagnosis of superior semi-circular canal dehiscence syndrome and a control group comprising 12 non-superior semi-circular canal dehiscence syndrome patients, all with available magnetic resonance imaging data. The imaging scans were anonymised, and reviewed blindly and independently by three experienced radiologists. There was low sensitivity and specificity, with average values of 47 per cent (range, 16.7-66.7 per cent) and 69 per cent (range, 66.7-75 per cent) respectively. Cohen's kappa was 0.75, indicating substantial inter-rater reliability. Given the low accuracy of 1.5T magnetic resonance imaging in identifying the bony defect in superior semi-circular canal dehiscence syndrome, despite its value in inner-ear imaging, computed tomography or equivalent should be used when superior semi-circular canal dehiscence syndrome is suspected.

Superior semi-circular canal dehiscence syndrome: quantifying the effectiveness of treatment from the patient's perspective.

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A Cohort Study Comparing Importance of Clinical Factors in Determining Diagnosis and Treatment for Superior Semicircular Canal Dehiscence Syndrome.

To determine which clinical factors have the strongest impact on determining diagnosis and decision for surgical repair for superior semicircular canal dehiscence syndrome (SCDS). A total of 81 patients presented with a suspicion for SCDS between October 2017 and October 2018. 38 patients ultimately were diagnosed with SCDS, and 28 chose surgical repair. Clinical factors of subjective patient symptoms (autophony, sensitivity to loud sounds, vertigo induced by loud sounds, dizziness, hearing their own heartbeats or other visceral organs) and audiogram findings (low frequency conductive hearing loss [CHL], bone-conduction hyperacusis, low cVEMP threshold [<80 db nHL], increased oVEMP [>17 μV] amplitudes) were analyzed with logistic regression to identify factors that predicted those who would ultimately be diagnosed with SCDS and those who would have surgical repair. Preoperative high-resolution CT imaging was performed on all patients. Significant predictors of presence of SCDS from logistic regression included low frequency CHL and increased oVEMP amplitude (p = 0.002 [OR 40, 95%CI 3.8-413], p = 0.001 [OR 93, 95%CI 6.8-1267], respectively). These were also significant predictors of individuals who chose to have surgical repair (p = 0.004 [OR 47, 95%CI 3.5-620], p = 0.001 [OR 126, 95%CI 8.2-1941], respectively). Area under the receiver operating characteristic curve (ROC curve) for these two variables are 93% for diagnosing SCDS and 94% for predicting choice for surgical repair. Low frequency CHL and increased oVEMP amplitude are the strongest predictive factors for making a diagnosis of SCDS and for choosing surgical repair.

Superior Semicircular Canal Dehiscence Syndrome Manifested as Menière’s Disease: A Case Report

The absence of a temporal bone overlying the superior semicircular canal causes superior semicircular canal dehiscence (SSCD). The vestibular symptom of SSCD syndrome (SCDS) is vertigo and audiologic symptoms include autophony, hyperacusis, and ear fullness. A 52-year-old man presented with left-sided unilateral hearing loss, aural fullness, and recurrent spinning-type vertigo. He had positive Hennebert sign and mixed-type hearing loss, with a prominent low-frequency air-bone gap. These symptoms reminded us of SCDS, and computed tomography (CT) revealed SSCD. However, the patient had not experienced vertigo until 1 week prior to the visit. In addition, the audiogram revealed fluctuation of hearing, which was aggravated when the vestibular symptoms manifested. Vertigo might be due to Menière’s disease rather than SCDS and SSCD was incidentally detected on CT. According to reviews, this is no reported case of SCDS manifested as Menière’s disease, so we report this case with a brief review of the literature.