Radiologic Classification of Superior Canal Dehiscence

Lookabaugh, Sarah; Kelly, Hillary R.; Carter, Margaret S.; Niesten, Marlien E F; McKenna, Michael J.; Curtin, Hugh D.; Lee, Dong Hoon

doi:10.1097/mao.0000000000000523

Cited by 62 publications

(61 citation statements)

References 25 publications

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“…Lookabaugh et al studied 392 temporal bones in 202 patients with symptomatic SSCD and found that the most common location of the dehiscence was the arcuate eminence (59.2%), followed by the medial downslope of the semicircular canal (28.8%), then the lateral upslope of the semicircular canal (7.6%). 22 The same study also reported that the arcuate eminence was found an average of 26.41 mm (range: 17.6-38.5) from the outer cortex of the temporal bone.…”

Section: Discussionmentioning

confidence: 75%

A Method of Locating the Dehiscence during Middle Fossa Approach for Superior Semicircular Canal Dehiscence Surgery

et al. 2017

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Superior semicircular canal dehiscence (SSCD) results from a defect in the middle cranial fossa floor. One challenge during SSCD repair is the lack of a consistent landmark. This study proposes a reference point above the external auditory canal at the level of the zygoma as the inferior craniectomy edge during surgery. This is a retrospective review of patients with SSCD. A total of 72 cases of SSCD in 60 patients were repaired via a middle fossa approach at a single institution. The distance from the proposed reference point to the dehiscence was statistically analyzed using Shapiro-Wilk's goodness-of-fit test and Student's -test. Average distance for all patients was 28.84 ± 2.22 mm (range: 22.96-33.43). Average distance for females was 29.08 mm (range: 24.56-33.43) versus 28.26 mm (range: 22.96-32.36) for males. There was no difference in distance by sex ( = 0.174). The distance measurements followed a normal distribution with 95% of the patients between 24.49 and 33.10 mm. This study analyzed a potential reference point during a middle fossa approach for SSCD surgery. The distance from this reference point to the SSCD was found to be consistent and may serve as a readily identifiable landmark in localizing the dehiscence.

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Section: Discussionmentioning

confidence: 75%

A Method of Locating the Dehiscence during Middle Fossa Approach for Superior Semicircular Canal Dehiscence Surgery

et al. 2017

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“…First, specimens in this study were prepared with defects of 0.5–3.5 mm in size over the arcuate eminence; however, SCD defects do vary in anatomical size, location and shape. The slope of the tegmen at the defect and its location along the canal influences the surgical approach 30 , which can in turn affect the orientation from which a surgeon repairs a defect. This has implications for the consequential position of wax, and volume of wax necessary to achieve a stable occlusion of the canal.…”

Section: Discussionmentioning

confidence: 99%

Characteristics of Wax Occlusion in the Surgical Repair of Superior Canal Dehiscence in Human Temporal Bone Specimens

Cheng

Kozin

Remenschneider

et al. 2016

Otology &Amp; Neurotology

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Hypothesis Superior canal dehiscence (SCD) repair using surgical bone wax may result in variable outcomes if large wax volumes are applied. Background SCD is a disorder characterized by a pathologic defect in the bony labyrinth of the superior semicircular canal (SSC), resulting in vestibular and/or auditory symptoms. Repair of SCD using bone wax can provide symptomatic relief, but surgical outcomes are variable. These observations may be associated with the inconsistency in the position and extension of intralabyrinthine bone wax during surgical repair. Methods A pathological model of SCD was created using cadaveric human temporal bones and a microdrill. Defects in the arcuate eminence 0.5–3.5 mm in length were repaired using surgical occlusion with bone wax. The volume of wax used in the repair was quantified. The position of bone wax was evaluated by direct visualization and imaging (computed tomography [CT]). To visualize wax on CT, specimens were repaired using radiopaque wax. Results Exceedingly small volumes of bone wax (3.0–5.0 mm2) reliably occluded the canal lumen. Multiple wax applications resulted in extension into the common crus and ampulla. The length of this extension was related to the number of applications. Conclusions Repair of SCD with bone wax occludes the bony defect completely in most cases. Wax can extend along the lumen of the superior canal beyond the limits of the dehiscence to reach the sensory neuroepithelium of the vestibular end organs. Limiting the number of wax applications is essential to avoid inadvertent injury to the delicate neurosensory systems.

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“…Since the normal stapedo-vestibular joint space is not always seen as a distinct space on high resolution CT, it may not be possible to confirm these pathologic changes on CT. CT is still useful in the evaluation of patients with suspected NOG related hearing loss, however, as CT can identify other etiologies of conductive hearing loss, including malleus fixation, otosclerosis, and third window syndromes. 15,16 …”

Section: Discussionmentioning

confidence: 99%

Temporal Bone Histopathology in NOG-Symphalangism Spectrum Disorder

Quesnel

Nadol

Nielsen

et al. 2015

Otology &Amp; Neurotology

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Objective To describe the human temporal bone histopathology in NOG-related Symphalangism Spectrum Disorder, a spectrum of congenital stapes fixation syndromes caused by mutations in the NOG gene. To discuss implications for clinical management. Patient A patient with a mutation in the NOG gene Intervention(s) Removal of temporal bones, post-mortem temporal bone computed tomography, histologic processing and review of temporal bones Main Outcome Measure(s) Temporal bone histopathology, and correlation with clinical, genetic, audiologic, and radiologic evaluations Results Both temporal bones demonstrated fixation of the stapes footplate to the otic capsule due to a circumferential bridge of calcified cartilage. In the right ear (unoperated), there was no additional abnormality of the ossicles or ossicular joints. In the left ear, fenestrations of the stapes footplate and the lateral semicircular canal were seen, consistent with a history of stapedectomy and fenestration procedure. Severe loss of spiral ganglion neurons (SGN) throughout the left cochlea accounted for the profound sensorineural hearing loss; there was a normal number of SGN in the right ear. In both ears, the cochleae demonstrated grossly preserved organs of Corti. Conclusion The temporal bone pathologic correlate for conductive hearing loss in this patient with a NOG mutation was circumferentially calcified cartilage bridging the stapedo-vestibular joint space. The temporal bone histopathology findings suggest that conductive hearing loss related to NOG mutation should be improved after stapedectomy; however, care must be taken in extrapolating to all patients with NOG mutations, as there may be variability in the pathology, especially given the variability of NOG spectrum disorders.

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Radiologic Classification of Superior Canal Dehiscence

Cited by 62 publications

References 25 publications

A Method of Locating the Dehiscence during Middle Fossa Approach for Superior Semicircular Canal Dehiscence Surgery

A Method of Locating the Dehiscence during Middle Fossa Approach for Superior Semicircular Canal Dehiscence Surgery

Characteristics of Wax Occlusion in the Surgical Repair of Superior Canal Dehiscence in Human Temporal Bone Specimens

Temporal Bone Histopathology in NOG-Symphalangism Spectrum Disorder

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