Dehiscences of the semicircular canals as discrete third window lesions of the inner ear (original) (raw)
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Posterior semicircular canal dehiscence in asymptomatic ears
Acta Oto-Laryngologica, 2010
Conclusions: This study revealed that, in the adult population, the final diagnosis of this entity can only be made by combining imaging with clinical tests. Objective: We developed the largest temporal bone multislice computed tomography (CT) scan study so far by including 410 cases to investigate the prevalence of posterior semicircular canal dehiscence in patients with symptoms unrelated to the inner ear. Methods: A prospective study was performed in 410 consecutive adult individuals who underwent temporal bone multislice CT scan examinations. Results: The prevalence of posterior semicircular canal dehiscence was determined to be 1.2%. No superior or lateral semicircular canal defect was detected in these five patients. All cases with posterior semicircular canal defect were male. In two cases the canal was located unilaterally, while in three cases the defects were present bilaterally. Otological examination and audiovestibular tests revealed no abnormal findings in any of the individuals.
Superior semicircular canal dehiscence: A new perspective
European journal of radiology open, 2017
To determine the use of multi-detector computed tomography (MDCT) in the diagnostic interpretation of superior semicircular canal dehiscence (SSCD) or thinning and its association with ear pathologies and to find whether it is an acquired condition and its association with increase in age. study was performed in a tertiary care institute present in a village, following approval of the institutional ethical committee. Retrospective review of temporal bone CT examinations performed between September 2016 and March 2017 was done. 1 mm interval axial images with sagittal and coronal reformatted images were reviewed for the presence of canal dehiscence and thinning by investigators. We characterised the Superior semicircular canal status as normal, frank dehiscence or thinning. Frank dehiscence was further classified anatomically as anterior limb, apex and posterior limb dehiscence.The patient list was then subcategorized into 5 age groups, and the prevalence of SSCD was calculated for e...
CT imaging of superior semicircular canal dehiscence: Added value of reformatted images
Acta Oto-Laryngologica, 2010
Conclusion: Superior semicircular canal dehiscence (SSCD) syndrome may present with various symptoms. CT scans previously interpreted as normal may show SSCD, especially if special reconstructions tailored for superior canal evaluation are added. Objectives: The purpose of this study was to investigate prevalence of SSCD, its length and its correlation with symptoms in patients who had previously undergone temporal bone CT examination that was reported normal and to demonstrate the importance of reformatted images in the diagnosis of SSCD. Methods: We retrospectively reviewed 108 patients who had undergone temporal bone CT examination for various symptoms and were reported as normal. High-resolution temporal bone CT imaging was performed with 1 mm slice thickness in the transverse plane. Each of the superior semicircular canals was evaluated in the plane of Pöschl and Stenver reformatted images together with axial images. Results: Ninety-three patients were included in the study. Nineteen patients with semicircular canal dehiscence were detected. The mean age of the study group was 45 years. Radiologic evidence of SSCD occurred in 23 of 186 temporal bones with a radiologic prevalence of 12%. The most common symptoms in dehiscent patients were vertigo, hearing loss and tinnitus. Defect lengths varied between 1 mm and 6.5 mm.
Posterior Semicircular Canal Dehiscence: CT Prevalence and Clinical Symptoms
Objective: To estimate the prevalence of and symptoms associated with posterior semicircular canal dehiscence (PSCD) compared to superior semicircular canal dehiscence (SSCD) and nondehiscent semicircular canals (NDSC). Study Design: Retrospective review. Setting: Academic tertiary referral center. Patients: Review of 412 temporal bone CT scans and associated patient records, excluding patients with prior mastoid or skull base surgery. Intervention(s): CT images (0.625 mm thick) were reviewed in the planes of the semicircular canals. Patient demographics and symptoms were tabulated and analyzed. Main Outcome Measure(s): Prevalence of PSCD and SSCD; degree of hearing loss; presence or absence of aural fullness, autophony, tinnitus, pulsatile tinnitus, disequilibrium, vertigo, and Tullio phenomenon. Results: Review of the 412 CT scans revealed 5 cases of PSCD (1.2%) and 20 cases of SSCD (4.9%). All patients with PSCD
Superior semicircular canal dehiscence: Diagnosis and management
Journal of Clinical Neuroscience, 2018
The authors provide an update on the clinical manifestations, diagnosis and various approaches to the treatment of superior semicircular canal dehiscence (SSCD). SSCD is a rare condition where the bone overlying the superior semicircular canal thins or dehisces causing characteristic clinical findings. Since this was first reported in 1998 by Minor and colleagues, there has been much advancement made in terms of diagnosis and treatment. Signs and symptoms include a wide variation of both vestibular and auditory manifestations. Diagnosis made solely on clinical signs is difficult due to how varied the presentations can be and the overlap with other otologic pathologies. High-resolution CT temporal scans have been the standard in confirming superior semicircular canal dehiscence, however, MRI FIESTA scans have recently been used to image SSCD. Additionally, audiometry and vestibular evoked myogenic potential (VEMP) testing are useful screening tools. Currently, the middle fossa approach is the most common and standard surgical approach to repair SSCD. The transmastoid, endoscopic and transcanal or endaural approaches have also been recently utilized. Presently, there is no consensus as to the best approach, material or technique for repair of SSCD. As we learn more, newer and less invasive approaches and techniques are being used to treat SSCD. We present a comprehensive review of SSCD, including clinical symptoms and presentation, histopathology, diagnosis, treatment strategies and outcomes of intervention.
B-ENT
Superior semicircular canal dehiscence (SSCD) can present with a variety of symptoms that can be predominantly auditory, predominantly vestibular or both. It can mimic a wide range of otological disorders, in particular otosclerosis-like stapes fixation. Our study revealed that, in 5.3% of our patients with clinically suspected otosclerosis, SSCD was detected in high-resolution multi-detector computed tomography (HRMDCT) of the temporal bone. We therefore emphasise the value of HRMDCT with reconstructions in the plane of the superior semicircular canal and perpendicular to the superior semicircular canal in the diagnostic work-up of each patient with a tentative diagnosis of otosclerosis-type stapes fixation. Where there are doubts, VEMP testing should be performed. We believe that a number of unexplained complications after an uneventful stapedotomy procedure might be explained by a pre-operatively undetected dehiscent superior semicircular canal and therefore unwarranted surgery. ...
The journal of international advanced otology, 2017
This study aimed to evaluate the efficacy of magnetic resonance imaging (MRI) for diagnosing superior semicircular canal dehiscence (SSCD). The radiological records of patients who were admitted to our clinic with complaints of otologic and neuro-otologic symptoms between October 2014 and December 2015 were retrospectively reviewed. Among these patients, those who underwent both computed tomography and MRI and were reported to have SSCD in the temporal bone on at least one side were included in the study group. MRI records of patients with a confirmed diagnosis were then assessed for the presence of SSCD. The left and right semicircular canals of 52 patients were evaluated in this study. The sensitivity and specificity of MRI in the diagnosis of SSCD was 89.06% and 90%, respectively. The positive and negative predictive values were 93.44% and 83.72%, respectively. The use of multiplanar reformats and angulation techniques during MRI assessment of patients with neuro-otologic symptom...
Use of Cone Beam Computed Tomography in the Diagnosis of Superior Semicircular Canal Dehiscence
Journal of clinical imaging science, 2014
Superior semicircular canal dehiscence is a relatively new syndrome in the field of otology. It is of unknown etiology presenting with a variety of vestibular and auditory symptoms and radiologic findings play a crucial role in its diagnosis. Cone beam computed tomography has been shown to be a powerful tool in the field of otolaryngology. It is a three dimensional technique that uses lower radiation resulting in fewer artifacts and offers higher resolution when compared with multislice computed tomography. It is considered to be an excellent imaging modality for radiological exploration of the ear.
Superior semicircular canal dehiscence: positive predictive value of high-resolution CT scanning
European Archives of Oto-Rhino-Laryngology, 2008
Patients with superior dehiscence (SCD) syndrome present with vertigo and oscillopsia evoked by loud sounds and changes in middle ear or intracranial pressure. The Wrst objective of this retrospective cohort study is to demonstrate that thin-section computed tomography (CT) scans reformatted in the plane of the superior semicircular canal (SSC) overestimate this anomaly compared to pathologic studies. The second objective of this study is to re-evaluate the positive predictive value of temporal bone scanning. All temporal bone CT scans with 0.55-mm collimation and reconstruction in the SSC plane performed over a 1-year period were analysed at a tertiary referral centre. CT-positive cases had their clinical data reviewed and patients were reexamined , if available. A total of 581 temporal bone CT-scans were analysed. A dehiscent-appearing superior canal was seen in 4.0% of studies while published pathologic studies report that only 0.5% of temporal bones SSCs have a dehiscence (P < 0.001). Of the 21 patients with positive temporal bone CTs, only 1 presented with suYcient clinical dues to identify the syndrome. Three additional patients did not have symptoms consistent with the diagnosis, but had surgery for a dehiscence of the tegmen mastoideum. When our Wndings are added to published data, the positive predictive value of temporal bone CT-scanning drops from 93 to 57%. The prevalence of dehiscent-appearing superior canal on thin-section temporal bone scanning with reformation in the SSC plane is much higher than anticipated by pathologic studies. Even with 0.55 mm-collimated helical CT and reformation in the SSC plane, the risk of overdiagnosis is present.
Superior Semicircular Canal Dehiscence: Pathophysiology and Surgical Outcomes
Current Otorhinolaryngology Reports, 2017
Purpose of Review Knowledge regarding superior semicircular canal dehiscence (SSCD) is quickly evolving. There are multiple aspects of SSCD that need to be considered in the diagnosis and treatment of this entity. Knowing the outcomes from treatment, the neuro-otologist is better equipped in counseling the patient regarding prognosis and individualized best management options. Recent Findings Now going on nearly 20 years since its initial description in the literature, the treatment options for SSCD have expanded and the results of treatment are being reported. Unfortunately, with variations in techniques and small numbers reported, comparison of differing techniques is challenging. Since 1998, our group has performed more than 400 SSCD surgical procedures of varying types. Much of this review is colored by this experience. We will review the pathophysiology and surgical outcomes for SSCD in order to give the reader a better appreciation of prognosis for treatment. Summary SSCD can have multiple unique presentations, with varying degrees of symptoms. The treatment options can range from non-surgical to minimally invasive to a variety of more invasive procedures. Knowing the pathophysiology and the outcomes from intervention can aid the physician in directing the patients care most appropriately.