BACKGROUND: Superior Semicircular Canal Dehiscence (SSCD) is a dehiscence of the otic capsule which normally lies over the superior semicircular canal. This database constitutes the largest series of SSCD patients to date.
OBJECTIVE: To determine what preoperative factors, if any, contribute to postoperative outcomes and evaluate symptom resolution in a large SSCD patient cohort.
METHODS: A single-institution, retrospective chart review collected patient demographics, intraoperative findings, and pre-and postoperative symptoms. Fisher\'s exact t-test was performed for unpaired categorical variables, with a significance level of p < 0.05.
RESULTS: 350 SSCD repairs were performed. The median age was 52 years (range: 17-86 years, ± 6.4 years), and the median follow-up duration was 4.6 months (range: 0.03-59.5 months, ± 6.8 months). Preoperative hearing loss was significantly associated with female sex (p = 0.0028). The most reported preoperative symptoms were tinnitus (77.4%), dizziness (74.0%), autophony (66.3%), amplification (63.7%), and disequilibrium (62.6%). Between patients who received unilateral versus bilateral SSCD repair, the greatest postoperative symptomatic resolution was seen in autophony (74.9%, p < 0.001), amplification (77.3%, p = 0.00027), hyperacusis (77.4%, p = 0.023), hearing (62.9%, p = 0.0063), and dizziness (54.6%, p < 0.001) for patients with unilateral SSCD repair.
CONCLUSIONS: Surgical repair via the middle cranial fossa approach can significantly resolve auditory, vestibular, and neurological symptoms of patients with SSCD. Although this is one of the largest single-institution SSCD studies to date, future multi-institutional, prospective studies would be beneficial to validate these results.

Introduction  The middle fossa craniotomy (MFCs) is commonly utilized for spontaneous cerebrospinal fluid (CSF) leaks, encephaloceles, and superior semicircular canal dehiscence (SSCD). This study compares postoperative outcomes of MFCs with and without LD use. Methods  A retrospective cohort study of adults over the age of 18 years presenting for the repair of nonneoplastic CSF leak, encephalocele, or SSCD via MFC from 2009 to 2021 was conducted. The main exposure of interest was the placement of an LD. The primary outcome was the presence of postoperative complications (acute/delayed neurologic deficit, meningitis, intracranial hemorrhage, and stroke). Secondary outcomes included operating room (OR) time, length of stay, recurrence, and need for reoperation. Results  In total, 172 patients were included, 96 of whom received an LD and 76 who did not. Patients not receiving an LD were more likely to receive intraoperative mannitol ( n  = 24, 31.6% vs. n  = 16, 16.7%, p  = 0.02). On univariate logistic regression, LD placement did not influence overall postoperative complications (OR: 0.38, 95% confidence interval [CI]: 0.05-2.02, p  = 0.28), CSF leak recurrence (OR: 0.75, 95% CI: 0.25-2.29, p  = 0.61), or need for reoperation (OR: 1.47, 95% CI: 0.48-4.96, p  = 0.51). While OR time was shorter for patients not receiving LD (349 ± 71 vs. 372 ± 85 minutes), this difference was not statistically significant ( p  = 0.07). Conclusion  No difference in postoperative outcomes was observed in patients who had an intraoperative LD placed compared to those without LD. Operative times were increased in the LD cohort, but this difference was not statistically significant. Given the similar outcomes, we conclude that LD is not necessary to facilitate safe MCF for nonneoplastic skull base pathologies.

UNASSIGNED: Vestibular loss and dysfunction has been associated with cognitive deficits, decreased spatial navigation, spatial memory, visuospatial ability, attention, executive function, and processing speed among others. Superior semicircular canal dehiscence (SSCD) is a vestibular-cochlear disorder in humans in which a pathological third mobile window of the otic capsule creates changes to the flow of sound pressure energy through the perilymph/endolymph. The primary symptoms include sound-induced dizziness/vertigo, inner ear conductive hearing loss, autophony, headaches, and visual problems; however, individuals also experience measurable deficits in basic decision-making, short-term memory, concentration, spatial cognition, and depression. These suggest central mechanisms of impairment are associated with vestibular disorders; therefore, we directly tested this hypothesis using both an auditory and visual decision-making task of varying difficulty levels in our model of SSCD.
UNASSIGNED: Adult Mongolian gerbils (n = 33) were trained on one of four versions of a Go-NoGo stimulus presentation rate discrimination task that included standard (\"easy\") or more difficult (\"hard\") auditory and visual stimuli. After 10 days of training, preoperative ABR and c+VEMP testing was followed by a surgical fenestration of the left superior semicircular canal. Animals with persistent circling or head tilt were excluded to minimize effects from acute vestibular injury. Testing recommenced at postoperative day 5 and continued through postoperative day 15 at which point final ABR and c+VEMP testing was carried out.
UNASSIGNED: Behavioral data (d-primes) were compared between preoperative performance (training day 8-10) and postoperative days 6-8 and 13-15. Behavioral performance was measured during the peak of SSCD induced ABR and c + VEMP impairment and the return towards baseline as the dehiscence began to resurface by osteoneogenesis. There were significant differences in behavioral performance (d-prime) and its behavioral components (Hits, Misses, False Alarms, and Correct Rejections). These changes were highly correlated with persistent deficits in c + VEMPs at the end of training (postoperative day 15). The controls demonstrated additional learning post procedure that was absent in the SSCD group.
UNASSIGNED: These results suggest that aberrant asymmetric vestibular output results in decision-making impairments in these discrimination tasks and could be associated with the other cognitive impairments resulting from vestibular dysfunction.

UNASSIGNED: To construct a symptoms-based prediction tool to assess the likelihood of superior canal dehiscence (SSCD) on high-resolution CT.
UNASSIGNED: Mathematical modeling was employed to predict radiologic evidence of SSCD at a tertiary neurotology referral center.
UNASSIGNED: A 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.
UNASSIGNED: The 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.

OBJECTIVE: To analyse the degree of pneumatisation of the temporal bone when there is an association between dehiscence of the superior semicircular canal and dehiscence of the tegmen tympani.
METHODS: We analysed a retrospective CT study of 124 selected cases. A single inclusion criterion was applied: the presence of a dehiscence of the tegmen tympani. On the other hand, the degree of temporal pneumatisation was assessed by axial and coronal planes, and has been divided into the following grades O, I, II and III, according to the status and relationship of the mastoid, the bony labyrinth, the petrous segment of the carotid canal and sigmoid sinus.
RESULTS: Of the 124 cases studied, 35 (28.2%) presented both dehiscences. In 26 of the 35 (47.3%), grade II pneumatisation, 4 (14,8%), grade I, and 5 (11,9%) grade III was observed, with a statistically significant relationship (p < 0.001). On the other hand, we did not find a significant relationship when relating both dehiscences in any age or sex group. However, when relating the degree of pneumatisation to sex, among those with grade III pneumatisation, the proportion of men (52.4%) was significantly higher than that of women (47.6%) (p = 0.017).
CONCLUSIONS: We have detected a statistically significant relationship between the coexistence of grade II pneumatisation and the presence of both dehiscences in the temporal bone.

The diverse etiopathogenesis of pulsatile tinnitus (PT) makes it a difficult condition to diagnose and treat. To describe the clinical features, investigations and diagnosis of patients presenting with pulsatile tinnitus (PT). Retrospective chart review in an otology unit of a tertiary care referral centre. All medical records of patients who had a complaint of pulsatile tinnitus during the period 1st January 2014-1st May 2020 were included in the study. Data regarding history, characteristics of tinnitus, examination findings, investigations and diagnosis were collected and analyzed. Sixty-four patients with complaints of PT presented to our clinic during this time period and were included in the study giving a prevalence of 0.09%. Definite diagnosis was made in 62 (96.8%) cases with a detailed history, clinical examination and tailored investigations. Pathologies diagnosed were paraganglioma (25%), superior semicircular canal dehiscence (20.3%), anterior inferior cerebellar artery loop (7.8%), sigmoid sinus wall dehiscence (10.9%), sigmoid sinus diverticulum (6.25%), jugular bulb anomalies (7.8%) and hyperpneumatised petrous apex (3.1%) among others. Rare causes encountered were IgG4 disease, far advanced otosclerosis, vestibular aqueduct dehiscence and idiopathic intracranial hypertension. Pulsatile tinnitus is a rare complaint in the Otology clinic. Almost all cases of PT can be diagnosed correctly and appropriate treatment initiated with a logical approach to investigations.

UNASSIGNED: Third window syndrome is a vestibular-cochlear disorder in humans in which a third mobile window of the otic capsule creates changes to the flow of sound pressure energy through the perilymph/endolymph. The nature and location of this third mobile window can occur at many different sites (or multiple sites); however, the most common third mobile window is superior semicircular canal dehiscence (SSCD). There are two essential objective diagnostic characteristics needed to validate a model of SSCD: the creation of a pseudoconductive hearing loss and cVEMP increased amplitude and decreased threshold.
UNASSIGNED: Adult Mongolian gerbils (n = 36) received surgical fenestration of the superior semicircular canal of the left inner ear. ABR and c+VEMP testing were carried out prior to surgery and over acute (small 1 mm SSCD, 1-10 days) or prolonged (large 2 mm SSCD, 28 days) recovery. Because recovery of function occurred quickly, condenser brightfield stereomicroscopic examination of the dehiscence site was carried out for the small SSCD animals post-hoc and compared to both ABRs and c+VEMPs. Micro-CT analysis was also completed with representative samples of control, day 3 and 10 post-SSCD animals.
UNASSIGNED: The SSCD created a significant worsening of hearing thresholds of the left ear; especially in the lower frequency domain (1-4 kHz). Left (EXP)/right (CTL) ear comparisons via ABR show significant worsening thresholds at the same frequency representations, which is a proxy for the human pseudoconductive hearing loss seen in SSCD. For the c+VEMP measurements, increased amplitude of the sound-induced response (N1 2.5 ms and P1 3.2 ms) was observed in animals that received larger fenestrations. As the bone regrew, the c+VEMP and ABR responses returned toward preoperative values. For small SSCD animals, micro-CT data show that progressive osteoneogenesis results in resurfacing of the SSCD without bony obliteration.
UNASSIGNED: The large (2 mm) SSCD used in our gerbil model results in similar electrophysiologic findings observed in patients with SSCD. The changes observed also reverse and return to baseline as the SSCD heals by bone resurfacing (with the lumen intact). Hence, this model does not require a second surgical procedure to plug the SSCD.

暂无摘要。

Objective  Tegmen tympani dehiscence in temporal multidetector computed tomography (MDCT) and superior semicircular canal dehiscence may be seen together. We investigated superior semicircular canal dehiscence in temporal MDCT and temporal magnetic resonance imaging (MRI). Methods  In this retrospective study, 127 temporal MRI and MDCT scans of the same patients were reviewed. In all, 48.8% ( n  = 62) of cases were male, and 51.2% ( n  = 65) of cases were female. Superior semicircular canal dehiscence and superior semicircular canal-temporal lobe distance were evaluated by both MDCT and MRI. Tegmen tympani dehiscence was evaluated by MDCT. Results  Superior semicircular canal dehiscence was detected in 14 cases (5.5%) by temporal MDCT and 15 cases (5.9%) by temporal MRI. In 13 cases (5.1%), it was detected by both MDCT and MRI. In one case (0.4%), it was detected by only temporal MDCT, and in two cases (0.8%), it was detected by only temporal MRI. Median superior semicircular canal-to-temporal distance was 0.66 mm in both males and females in temporal MDCT and temporal MRI. In both temporal MDCT and temporal MRI, as superior semicircular canal-to-temporal lobe distance increased, the presence of superior semicircular canal dehiscence in temporal MDCT and temporal MRI decreased. Tegmen tympani dehiscence was detected in eight cases (6.3%) on the right side and six cases (4.7%) on the left side. The presence of tegmen tympani dehiscence in temporal MDCT and the presence of superior semicircular dehiscence in MDCT and MRI increased. Conclusion  Superior semicircular canal dehiscence was detected by both MDCT and MRI. Due to the accuracy of the MRI method to detect superior semicircular dehiscence, we recommend using MRI instead of MDCT to diagnose superior semicircular canal dehiscence. Moreover, there is no radiation exposure from MRI.

Superior semicircular canal dehiscence (SSCD) is characterized by temporal bone thinning, which creates an opening between the inner ear and middle cranial fossa. Ehlers-Danlos syndrome, hypermobility type (EDS-HT) is a genetic collagen synthesis disorder, often resulting in bony abnormalities. We present the case of a 39-year-old female with EDS-HT who exhibited the otological symptoms characteristic of bilateral SSCD. High-resolution computed tomography (CT) scans confirmed the diagnosis. The patient elected for middle fossa craniotomy and noted symptomatic improvement. Due to its potential to confer bone fragility, EDS-HT may predispose SSCD development. Further examination of the relationship between these disorders is necessary.