Figure - available from: Frontiers in Neurology
This content is subject to copyright.
Illustrations depicting surgical repairs of SCD. (A) Plugging or occlusion of an arcuate eminence defect via middle fossa craniotomy approach. (B) CT image in the Pöschl view following repair. Occlusion was performed in a cadaveric temporal bone model of SCD using contrast-infused surgical bone wax. (C) Transmastoid approach for repair of SCD. A labyrinthotomy is created in the ascending and descending limbs of the superior semicircular canal and plugged to isolate the SCD. (D) Resurfacing or capping an arcuate eminence defect. This approach attempts to create a seal without occluding the superior semicircular canal lumen. *Modified from Cheng et al. (16).
Source publication
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 t...
Citations
... The pathogenesis of SSCD remains a subject of ongoing research. While trauma and congenital malformations have been implicated in some cases, it is believed that anatomical variations and degenerative processes also contribute to the development of this condition [5][6][7]. Genetic factors may play a role as well, as evidenced by familial cases reported in the literature. Unravelling the underlying mechanisms of SSCD pathogenesis is crucial for a deeper understanding of the condition and the development of targeted therapeutic interventions. ...
... As for the techniques used, there is the option of plugging, resurfacing, or a combination of both, and even the reinforcement of the round window. In SSCD in relation with the superior petrosal sinus (SSCD-SPS) cases, occlusion of the superior petrosal sinus using coils can be used [3,[5][6][7]10]. ...
... However, even with optimization, it can lead to overestimation of dehiscence size. Advances in imaging techniques, such as cone-beam volumetric tomography (Cone-beam CT, also known as flat panel CT, FPCT, or digital volume tomography, DVT), have enhanced detection accuracy compared to multi-slice CT, allowing higher resolution [6,17]. ...
Purpose
Most of Superior Semicircular Canal Dehiscence (SSCD) are located in the apical region of the SSC. However, in a small number of cases, it may be situated in the medial wall, causing the SSC to contact with the superior petrosal sinus (SPS). The aim of this study is to describe four patients with SSCD involving the superior petrosal sinus (SSCD-SPS) and to perform a review of the literature.
Methods
Observational retrospective study of patients diagnosed of SSCD-SPS in a tertiary referral center. A systematic review was made, identifying 7 articles in the literature. Clinical presentation, complementary test (pure-tone audiometry, PTA; vestibular evoked myogenic potential, VEMP; computed tomography, CT), therapeutic management and outcomes were reported.
Results
Four new cases of SSCD-SPS are reported, in three of them a transmastoid plugging was performed. 54 patients with SSCD-SPS (57 dehiscences) were reported in the literature. The most frequent symptoms were aural pressure (57.41%) and vertigo provoked by pressure/Valsalva (55.55%). Conductive hearing loss was the most common finding in PTA (47.37%). Abnormally low thresholds were observed in 59.46% of reported VEMP. Transmastoid approach was used in ten cases, middle fossa approach in four, round window reinforcement in one, and occlusion of the SPS using coils in two.
Conclusions
Within SSCD, we have encountered a rare subtype characterized by its medial wall location in close proximity to the SPS. This subgroup needs special consideration as it has shown its own distinct characteristics. Regarding therapeutic management, we advocate a transmastoid approach.
... Abb. 2c, e; [7,9,17]). ...
... eines Drittfenstersyndroms bisher nicht beurteilen. Weitere Studien sind notwendig, um den zusätzlichen Nutzen im klinischen Alltag zu beurteilen [9]. ...
Zusammenfassung
Hintergrund
Die Diagnostik von Drittfenstersyndromen stellt in der klinischen Praxis häufig eine Herausforderung dar.
Ziel der Arbeit
Die vorliegende Arbeit gibt einen aktuellen Überblick über diagnostische Optionen bei diesen Krankheitsbildern, mit besonderem Fokus auf das Syndrom der oberen Bogengangsdehiszenz (SCDS), das Syndrom des erweiterten vestibulären Aquädukts (LVAS) und die X‑chromosomale Malformation der Cochlea.
Material und Methoden
Dazu erfolgte eine Literaturrecherche in der Datenbank PubMed bis Dezember 2023 und die Aufarbeitung eigener Fälle.
Ergebnisse
Audiovestibuläre Testverfahren zur Diagnose eines Drittfenstersyndroms werden in der Literatur am häufigsten im Rahmen des SCDS beschrieben. Für vestibulär evozierte myogene Potenziale wurden hier Grenzwerte mit unterschiedlichen Sensitivitäten/Spezifitäten für verschiedene Messparameter definiert. Neuere Entwicklungen umfassen die Anwendung der Elektrocochleographie, der Breitbandtympanometrie, des Video-Kopfimpulstests und des vibrationsinduzierten Nystagmus. Beim LVAS kommen zunehmend genetische Analysen zum Einsatz.
Schlussfolgerung
Die Diagnose eines Drittfenstersyndroms ergibt sich immer aus der Synthese von Symptomen, klinischen Zeichen, apparativen Untersuchungsbefunden und der Bildgebung.
... These include vertigo induced by pressure or sound, oscillopsia, bone conduction hyperacusis, pulsatile tinnitus, and autophonyand less specific symptoms of conductive hearing loss, aural fullness, and chronic disequilbrium. [1][2][3][4][5] Given this variable symptom profile which overlaps significantly with other otologic and non-otologic conditions, diagnosis can be challenging. Contributing to diagnostic difficulty is the possibility of superior canal dehiscence (SCD) without symptoms. ...
Objective
To characterize the diagnostic yield of patients undergoing evaluation for superior canal dehiscence syndrome (SCDS), and identify alternative conditions diagnosed in patients suspected of, but not ultimately diagnosed with, SCDS.
Methods
Diagnostically undifferentiated adult patients suspected of having SCDS were identified between 2016 and 2021 at a tertiary academic medical system. Patients were categorized by diagnostic testing, radiographic superior semicircular canal (SSC) abnormality, symptoms, evaluating clinician specialty, operative intervention, and diagnosis. Differences among groups were assessed for statistical significance.
Results
Of 1242 candidate patients, 477 met inclusion criteria—evaluation by a clinician with SCDS on their differential diagnosis prior to diagnostic imaging. The mean (SD) age was 53.0 (15.0) years and 70.6% were female. A total of 364 patients underwent subsequent diagnostic imaging, and among these, 164 (45.1%) had a radiographic SSC abnormality with 99 (27.2%) receiving a diagnosis of SCDS (two cases of “near dehiscence syndrome”). One third (33.3%) of patients with SCDS underwent operative repair. Most clinicians with the initial suspicion for SCDS were otolaryngologists (90.6%), who had greater diagnostic yield than clinicians from other specialties (22.2% vs. 6.7%, p = 0.012). Patients not diagnosed with SCDS alternatively received 21 unique diagnoses and 52.1% (138/265) were not definitively diagnosed with any condition.
Conclusions
This study characterizes the diagnostic incidence, or yield, of newly identified radiographic SSC abnormalities (45.1%) and SCDS (27.2%) among people suspected of having SCDS. Considerable overlap in presentation between SCDS and other conditions exists, and there is need for improvement in efficiently diagnosing patients with SCDS and audio‐vestibular complaints in general.
Level of Evidence
III Laryngoscope , 2024
... Lack of training and no access to equipment that could measure WAI were the primary reasons that the responding South African audiologists were not performing WAI. Furthermore, the complexity of interpreting WAI measurements is also considered one of the primary reasons behind limited acceptance of WAI by clinicians (Eberhard et al., 2021;Grais et al., 2021;Sanford et al., 2013). ...
... The lack of clinical confidence in interpreting WAI is certainly related to the complex nature of the measurement results (Eberhard et al., 2021;Grais et al., 2021;Sanford et al., 2013). Accordingly, interpretation of WAI results must be simplified. ...
Purpose
middle-ear mechanics. In contrast to standard tympanometry, which is generally measured at a single stiffness-dominated low frequency, WAI detects mechanical effects on both the mass and stiffness properties of the middle ear across a wide range of frequencies, resulting in a more comprehensive assessment of middle-ear mechanics in healthy and pathological ears. Despite a plethora of research demonstrating the clinical utility of this measure, clinical adoption of WAI is still limited. This work explores audiologists' use and perceptions of WAI, with the goal of identifying the barriers to its clinical adoption.
Method
A survey on the perception and use of WAI by clinical audiologists in the United States was developed and administered using the Research Electronic Data Capture application. The survey was distributed broadly across the United States. Participation was voluntary and anonymous, and no compensation was provided.
Results
Findings from 132 survey respondents across 32 states were included in the analyses. Overall, findings suggest the largest barriers to clinical adoption of WAI are lack of access to equipment that measures WAI and lack of training and/or confidence in measuring or interpreting WAI.
Conclusions
Several barriers to clinical adoption of WAI were identified. However, findings also provide optimism in that audiologists utilizing WAI find it more useful than standard tympanometry, and most audiologists who do not currently use WAI are open to implementing the measure in their clinical practice. We proposed steps to address the highest priority issues and increase the clinical viability of WAI.
... Symptoms are caused by changes to inner-ear biomechanics in the presence of a dehiscence, a "third window" (5,11,12). The biomechanical changes can be measured objectively. ...
... Over time, from 3-month to 2-year follow-up, there was a statistically significant decline in THI score ( p = 0.01). The median HHI total score improved from 23 (IQR, 12-29) to 9 (1-19) at 1-year follow-up ( p = 0.04; CI, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. There was no statistically significant change in HHI score over time from the 3-month to 2-year follow-up ( p = 0.73). ...
... We found pathological vHIT function in four of six superior semicircular canals preoperatively, of which some normalized after surgery. The previously proposed auto-plugging hypothesis suggests that dural herniation and compression of the membranous labyrinth imped normal endolymphatic flow and normal VOR response (5,16,(36)(37)(38). However, the dural compression must create insufficient occlusion as the four patients with abnormal VOR response were both symptomatic and showed objective measures of a third window by VEMP and audiometric testing. ...
Objective:
We assess symptom control, reversal and stability of objective third-window indicators, and hearing and balance function after transmastoid superior canal dehiscence plugging. To do this, we combine patient self-assessment questionnaires with auditory and vestibular test data collected at a preoperative and multiple postoperative visits.
Study design:
Prospective cohort study.
Setting:
Tertiary referral center.
Patients:
Patients who underwent transmastoid plugging for superior canal dehiscence from 2012 to 2020.
Interventions:
Plugging of the superior semicircular canal using the transmastoid approach.
Main outcome measures:
Patients were evaluated preoperatively, 3-month postoperative, and at yearly follow-ups (up to 8 yr postoperative). Self-assessment questionnaires included Autophony Index, Dizziness Handicap Inventory, Tinnitus Handicap Inventory, and Hearing Handicap Inventory. Objective tests included audiometry, cervical vestibular evoked myogenic potential, ocular vestibular evoked myogenic potential, and video head impulse test.
Results:
There was a statistically significant improvement in Autophony Index and Hearing Handicap Inventory total scores from the preoperative evaluation to 1 year postoperative. Dizziness Handicap Inventory and Tinnitus Handicap Inventory total scores also improved but statistically insignificant. Cervical and ocular vestibular evoked myogenic potential amplitudes and low-frequency air-bone gap showed statically significant reversal of the third-window effect preoperative versus 1 year postoperative. Video head impulse test of the superior semicircular canal revealed cases of pathological function preoperative with postoperative recovery. Results were stable over time.
Conclusions:
Superior canal dehiscence repair resolves symptoms of autophony and improves hearing disability. Objective third-window indicators reverse and show long-term stability. Auditory and vestibular function is preserved postoperative, even superior semicircular canal function may be normal. Data suggest that surgical outcomes should not be evaluated until 1 year postoperative.
... It has been postulated that the hallmark symptoms of SSCD are secondary to a 'third window' effect [1][2][3][4][5][6][7][8]. Briefly, dehiscence of the segment of temporal bone, located above the superior semicircular canal, creates a 'third window,' which increases inner-ear immittance and perturbs normal endolymph dynamics, particularly when exposed to high-level sounds or pressure changes [8][9][10][11]. Hence, patients with suspected SSCD will typically show an air-bone gap (conductive hearing loss) and rotational nystagmus induced by pressure changes (Henebert's sign) or sound (Tullio phenomenon) upon examination [2,[10][11][12]. ...
... Briefly, dehiscence of the segment of temporal bone, located above the superior semicircular canal, creates a 'third window,' which increases inner-ear immittance and perturbs normal endolymph dynamics, particularly when exposed to high-level sounds or pressure changes [8][9][10][11]. Hence, patients with suspected SSCD will typically show an air-bone gap (conductive hearing loss) and rotational nystagmus induced by pressure changes (Henebert's sign) or sound (Tullio phenomenon) upon examination [2,[10][11][12]. ...
... Although the exact etiology of SSCD is unclear, it is thought that both primary and secondary factors are involved. The presence of a thin segment of bone overlying the superior semicircular canal is a strong predisposing factor for SSCD following a trauma to the head or increased inner-ear pressure [2,[10][11][12]15,16]. ...
Patient: Male, 52-year-old
Final Diagnosis: Superior semicircular canal dehiscence • tegmen tympani dehiscence
Symptoms: Dizziness • hearing loss • vertigo • vomiting
Clinical Procedure: —
Specialty: Radiology
Objective
Rare disease
Background
Superior semicircular canal dehiscence is an inner-ear pathology which presents with vertigo, disequilibrium, and hearing loss. Although the exact etiology of superior semicircular canal dehiscence is unknown, it is thought that an increase in middle-ear pressure disrupts a thin overlying temporal bone. Superior semicircular canal dehiscence is frequently seen in association with dehiscence of the tegmen tympani, which overlies the middle ear. Here, we present a case report of a 52-year-old Puerto Rican man with vertigo, dizziness, vomiting, and mild hearing loss associated with superior semicircular canal and tegmen tympani dehiscence after performing improper scuba diving techniques.
Case Report
A 52-year-old Puerto Rican man presented to the emergency department with vertigo, dizziness, vomiting, and mild hearing loss in the right ear. The symptoms began shortly after scuba diving with inadequate decompression techniques on ascent. He was treated with recompression therapy with mild but incomplete improvement in symptoms. Bilateral temporal magnetic resonance imaging was suggestive of segmental dehiscence of the right superior semicircular canal and tegmen tympani. High-resolution computed tomography of the temporal bone confirmed right superior semicircular canal and tegmen tympani dehiscence with an intact left inner ear.
Conclusions
The increased inner-ear pressure that occurs during scuba diving can lead to dehiscence of the superior semi-circular canal and tegmen tympani, causing vertigo and hearing loss. Performance of improper diving techniques can further increase the risk of dehiscence. Therefore, appropriate radiologic evaluation of the inner ear should be performed in such patients.
... For example, preliminary efforts show promising outcomes for the utility of artificial intelligence algorithms to process the broad range of information provided by WAI and identify the most informative diagnostic features in measurements. [50][51][52] In addition to presurgical diagnosis, there are efforts to also examine the use of WAI in postsurgical assessment of outcomes, and restoration of function. 48,[53][54][55] Another area of active development is the use of WAI technology to evaluate middle ear muscle reflexes (MEMR). ...
Clinical assessment of middle ear function has undergone multiple transformations and developments since the first acoustic impedance measurements were made in human ears nearly a century ago. The decades following the development of the first acoustic impedance bridge by Metz in 1946 witnessed a series of technological advancements leading to the widespread use of single-frequency admittance tympanometry in the 1960s. In the 1970s, multi-frequency and multi-component tympanometry (MFT) emerged for clinical use, allowing for a better understanding of the middle ear acoustic-mechanical response at frequencies between 200 and 2,000 Hz. MFT has not gained widespread clinical adoption despite its advantages over single-frequency tympanometry. More recent technological developments enabled assessment for frequencies greater than 2,000 Hz, leading to the advent of wideband acoustic immittance measures with capabilities for comprehensive assessment of middle ear acoustic mechanics, and a great potential for use of acoustic immittance testing in various diagnostic practices. This article reviews important historical markers in the development and operation of middle ear assessment tools and analysis methods. Technical and clinical factors underlying the emergence and adoption of different acoustic immittance tests as a standard of clinical practice are described. In addition, we discuss the likelihood for widespread adoption of wideband acoustic immittance and wideband tympanometry in future clinical practice.
... Для розуміння симптоматики та можливих підходів до визначення діагностичних методів і тактики лікування доцільно згадати анатомо-фізіологічні особливості структур внутрішнього вуха [17,27,32]. Вертикальний півколовий канал орієнтований у вертикальній площині перпендикулярно довгій осі піраміди скроневої кістки, а горизонтальний -під кутом 30° до горизонталі, що і визначає напрямок ністагму (осцилопсії) при виникненні подразнення в одному з лабіринтів. ...
... При огляді у пацієнтів з «синдромом третього рухливого вікна» ні анамнестично, ні клінічно не виявляють патологію середнього вуха: мікроскопічно барабанна перетинка інтактна, а барабанна порожнина адекватно вентильована [23,27]. ...
The report presents modern views on the “third mobile window syndrome”, starting with the anatomical and physiological features of the inner ear function, both in normal conditions and in the presence of an additional opening in the bony labyrinth, which changes the hydrodynamic resistance of fluid flow in the perilymphatic space. Characteristic symptoms and modern views (sometimes hypothesis) on the causes of its occurrence are described in detail. Attention focused on diagnostic methods at the outpatient and clinical conditions of a highly specialized department. The latest data on the modern classification of this syndrome and the conclusions of the consensus of the International Barani Society in 2021 are presented. Own series with a detailed description of the features of each case, illustration of the audiometric and tomographic images and successful results of surgical treatment are presented. In the conclusions, the attention of practicing doctors is focused on the signs of the “third mobile window syndrome” which can be detected at the outpatient service – pressure or sound-induced vertigo, bone conduction hyperacusis, and pulsatile tinnitus.
... It's possible that SCD will result in the failure of prenatal and postnatal development of the temporal bone. Some of the potential causes of acquired SCD include intracranial hypertension, neoplasms, vascular malformations, chronic osteomyelitis, fibrous dysplasia, and head trauma with fractures to the temporal bone (Eberhard, Chari, Nakajima, Klokker, Cayé-Thomasen, & Lee, 2021). Superior semicircular canal dehiscence has many symptoms seen as abnormal auditory or vestibular signs. ...
... Myogenic Potentials (VEMPs) (Eberhard et al., 2021;Ward, Carey, & Minor, 2017). Established clinical testing that indicates supranormal bone conduction thresholds, low-frequency airbone gap with present acoustic reflexes, low threshold cervical VEMP, and elevated ocular VEMP amplitudes are beneficial in directing therapeutic options for symptomatic patients who have radiologic SSCD. ...
... SSCD is divided into two types of dehiscence: frank dehiscence (the bone overlying the SSC is absent) and near dehiscence (the bone overlying the SSC is very thin). 15 Prior ear trauma was defined as any pressure-induced or concussive injury that can exacerbate SSCD symptoms. Examples include barotrauma such as scuba diving injuries or concussive blows to the head. ...
Objective:
The present study investigates risk factors and clinical outcomes of postoperative pneumolabyrinth following the middle cranial fossa approach for superior semicircular canal dehiscence repair, a complication that has not been documented previously.
Study design:
Retrospective cohort study.
Setting:
Tertiary/quaternary care referral center.
Methods:
We conducted a retrospective review of 332 middle cranial fossa procedures from 2014 to 2020 at a tertiary/quaternary care institution. Upon identifying pneumolabyrinth cases from postoperative computed tomography temporal bone scans, we conducted multivariable logistic regression analysis to explore demographic and clinical factors that were independently linked to this complication. We also compared the rates of postoperative symptoms among patients with different grades of pneumolabyrinth.
Results:
We identified 41 (12.3%) pneumolabyrinth cases. Patients with older age, higher preoperative pure tone average, and frank dehiscence were at higher risk for pneumolabyrinth. Furthermore, patients with pneumolabyrinth reported significantly higher rates of postoperative dizziness and exhibited significantly greater pure tone average and air-bone gap postoperatively as compared with patients without pneumolabyrinth. Finally, higher-grade pneumolabyrinth was associated with increased rates of postoperative hearing loss, and grade III pneumolabyrinth was associated with higher rates of postoperative tinnitus vs grade I and II cases.
Conclusion:
Pneumolabyrinth following the middle cranial fossa approach was associated with poor clinical outcomes, including dizziness and auditory impairment. Old age, high preoperative pure tone average, and frank dehiscence were risk factors for this complication. The highlighted parameters may be important to note when considering this approach as a treatment option and while monitoring postoperative recovery.
