Influence of aging and menopause in the origin of the superior semicircular canal dehiscence

Patient Sex Mediates the Influence of Patient Age on Superior Canal Dehiscence Repair Outcome

OBJECTIVE

To investigate the independent and interactive effects of patient age and sex on superior canal dehiscence (SCD) repair outcomes.

METHODS

This was a cohort study of consecutive SCD repairs via the middle fossa approach at an institution between 2011 and 2022. We constructed multivariable regression models assessing surgical outcomes with age and sex as the primary predictors. Models controlled for surgery duration, follow-up duration, and relevant surgical and medical history. Subsequently, we repeated each model with the incorporation of an interaction term between patient age and sex.

RESULTS

Among 402 repairs, average age was 50 years, and 63% of cases were females. There was a significant interaction between patient age and sex with respect to symptom resolution score (SRS) (adj. β 0.80, 95% C.I. 0.04-1.56). Older age was associated with lower SRS among females (-0.84, -1.29 to -0.39 point per year) but not significantly associated with SRS among males (0.04, -0.65 to 0.56 point per year). Furthermore, older age independently predicted a greater magnitude of increase in air conduction at 8000 Hz following surgery regardless of sex (adj. β 2.1, 0.2-4.0 dB per 10-year increase).

CONCLUSIONS

This is the first study on the interactive effect between patient age and sex with respect to SCD repair outcomes. Older age predicted poorer symptomatic response among female patients but did not predict symptomatic response among male patients. Furthermore, older age predicted more severe high-frequency hearing loss following SCD repairs among both female and male patients.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:3363-3370, 2024.

The evaluation of superior semicircular canal in patients with unilateral cleft lip and palate using CBCT

OBJECTIVES

The present study aims to evaluate the thickness and radiological patterns of the superior semicircular canal (SSC) in patients with unilateral cleft lip and palate (CL/P).

METHODS

Cone beam computed tomography (CBCT) images of the patients were evaluated in axial and Pöschl planes. CBCT images of 84 patients with unilateral CL/P and 168 healthy individual controls were included in the study. Three study groups were established: the CS-CL/P group (cleft side temporal bones of the CL/P patients), NCS-CL/P (non-cleft side temporal bones of the CL/P patients) and the control group. The radiological patterns of SSCs were categorized as dehiscence, papyraceous, normal, pneumatised and thick. The minimum bone thickness of SSC was measured.

RESULTS

It was found that the CS-CL/P group had a higher prevalence for SSCD compared to both the NCS-CL/P group and the control group. CS-CL/P group had a higher prevalence of dehiscence type and papyraceous type compared to the control group. The SSC thickness on the CS-CL/P patients was thinner than the NCS-CL/P patients and the control group sides (p = 0.033 and p < 0.001, respectively).

CONCLUSIONS

The mean thickness of SSC was found significantly lower in the CS-CL/P group compared to both the NCS-CL/P group and the control group. The elevated prevalence of dehiscence and papyraceous types in the CS-C/LP group compared to the control group implies that the presence of a cleft may be a predisposing factor for these types.

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

Objective

It 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.

Methods

This 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.

Results

A 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.

Conclusion

Our 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.

Evaluation of Superior Semicircular Canal Morphology and Its Relationship with Glenoid Fossa Roof Thickness Using Cone Beam Computed Tomography

Purpose

This study aimed to evaluate the bone thickness of the superior semicircular canal (SSC) roof and its relationship with the roof thickness of the glenoid fossa (RGF).

Methods

The cone beam computed tomography (CBCT) images of 280 patients (560 temporal regions) were surveyed. The lowest thickness of the SSC roof was measured and categorized based on the radiological patterns of the Cisneros et al. classification. The thickness of GF and the presence of dehiscence in this part were determined, as well. The relationship between the thickness of the GF roof and the bone thickness covering the SSC was also assessed.

Results

The mean thickness of the SSC roof was 0.93 ± 0.48 mm, with no significant difference among different age groups and genders (p > 0.05). However, superior semicircular canal dehiscence (SSCD) was more prevalent among females over 45 years old. Similarly, the individuals with the dehiscence of the GF roof had a 12.93-fold higher chance of SSCD development.

Conclusions

The results indicated that the thickness of the bone overlying the SSC was significantly related to the roof thickness of the GF. However, an increase in age resulted in no significant change in the bone thickness of the SSC roof. Gender also had no role in changing the thickness of the bone overlying the SSC. Considering the decrease in the thickness of the SSC roof among females over 45 years of age, menopause may be responsible for this occurrence as well as for the increase in the prevalence of SSCD.

Dehiscence or thinning of bone overlying the superior semicircular canal in idiopathic intracranial hypertension

STUDY DESIGN

Retrospective cohort.

OBJECTIVES

The objective of the study is to evaluate a relationship between idiopathic intracranial hypertension (IIH) and superior semicircular canal dehiscence (SSCD) of bone overlying the superior semicircular canal (SSC).

MATERIALS AND METHODS

A total of 57 (114 ears) individuals, 20 of whom were controls and 37 of whom were IIH, were included in the study. Individuals were evaluated with 0.8 mm slice thickness computed tomography (CT) images for SSC bony roof thickness and SSCD. Thickness of the bony roof over the SSC was graded from Grade 1 to Grade 4. Grade 3 was defined as pre-dehiscence and Grade 4 as dehiscence.

RESULTS

Bony roof thickness was 1.25 mm in the control group and 0.76 mm in the IIH group. When bony roof thickness was compared between the groups, it was found to be significantly thinner in the IIH group (p = 0.012). In the IIH group, while dehiscence was detected in 25 of 74 ears, no dehiscence was detected in 49 ears. In the control group, while dehiscence was detected in 5 ears, no dehiscence was detected in 35 ears. The difference is statistically significant (p = 0.015). The correlation between bony roof thickness and cerebrospinal fluid (CSF) pressure in the IIH group was not statistically significant (p = 0.343; rho = 0.110). The correlation between bony roof thickness and age in the IIH group was not statistically significant (p = 0.082; rho =  - 0.164).

CONCLUSION

Increased CSF pressure in patients with IIH may cause chronic, progressive, and irreversible damage to the bone of the SSC and, according to our study, the rate of SSCD was found to be high in IIH patients.

The evaluation of superior semicircular canal bone thickness and radiological patterns in relation to age and gender

PURPOSE

The present study aims to evaluate the superior semicircular canal (SSC) bone thickness and radiological patterns in relation to age and gender in a Turkish population using cone beam computed tomography (CBCT).

METHODS

A total of 450 temporal bones were evaluated in the study by two examiners. The radiological patterns of SSC were categorized as follows: dehiscent, papyraceous, normal, thick and pneumatised patterns. The bone thickness of SSCs were measured.

RESULTS

The mean bone thickness of the SSC for females was 1.079 ± 0.8 mm. For males, the mean bone thickness was 0.952 ± 0.6 mm. There was no significant difference between males and females for the mean bone thickness of the SSC. (p > 0.05) The normal pattern was found in 258 temporal bones (57.3%). Seventy-two cases (16%) were defined as "papyraceous pattern"; 23 cases (5.1%) were defined as "thick pattern" and 42 cases (9.3%) were defined as "pneumatised pattern". SSC dehiscence was determined in 55 cases (12.2%). There was no significant difference between radiological patterns for age groups and gender (p > 0.05).

CONCLUSION

There was no significant relationship between SSC bone thickness with age and gender. The radiological patterns of SSC were not associated with age and gender. Radiologists evaluating the head and neck region for various reasons should be aware of these structures and report not only the SSC dehiscence but also the papyraceous pattern.

Superior Semicircular Canal Dehiscence : Covering Defects in Understanding from Clinical to Radiologic Evaluation

Superior semicircular canal dehiscence alters the normal fluid mechanics of the vestibulocochlear system and can be a debilitating condition. This article reviews the current understanding of the bony labyrinthine defect, including symptoms, etiology, surgical approach, as well as preoperative and postoperative imaging pearls.

Concomitant Dehiscences of the Temporal Bone: A Case-Based Study

Otic capsule dehiscences create a pathological third window in the inner ear that results in a dissipation of the acoustic energy consequent to the lowered impedance. Superior semicircular canal dehiscence (SSCD) was identified by Minor et al in 1998 as a syndrome leading to vertigo and inner ear conductive hearing loss. The authors also reported the relation between the dehiscence and pressure- or sound-induced vertigo (Tullio's phenomenon). Prevalence rates of SSCD in anatomical studies range from 0.4% to 0.7% with a majority of patients being asymptomatic. The observed association with other temporal bone dehiscences, as well as the propensity toward a bilateral or contralateral "near dehiscence," raises the question of whether a specific local bone demineralization or systemic mechanisms could be considered. The present report regard a case of a patient with a previous episode of meningitis, with a concomitant bilateral SSCD and tegmen tympani dehiscence from the side of meningitis. The patient was affected by dizziness, left moderate conductive hearing loss, and pressure/sound-induced vertigo. Because of disabling vestibular symptoms, the patient underwent surgical treatment. A middle cranial fossa approach allowed to reach both dehiscences on the symptomatic side, where bone wax and fascia were used for repair. At 6 months from the procedure, hearing was preserved, and the vestibular symptoms disappeared.

Association of Intracranial Hypertension With Calvarial and Skull Base Thinning

OBJECTIVE

Determine if patients with increased opening pressure (OP) on lumbar puncture (LP) have thinner calvaria and skull bases.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary referral center.

PATIENTS

Patients (≥18 yr of age) who had a recorded OP on LP and high-resolution computed tomography imaging of the head. Patient age, sex, body mass index were calculated. Intracranial hypertension (IH) was defined with an OP≥25 cm-H2O and low intracranial pressure with an OP<15 cm-H2O.

INTERVENTION

Measurement of calvarial, zygoma, and skull base thickness when blinded to OP with three-dimensional slicer and radiologic calipers.

MAIN OUTCOME MEASURES

Association of calvarial, skull base, and zygoma thickness with OP and age.

RESULTS

Fifty-eight patients were included with a mean (SD) age of 53.1 (16.2) years and average (SD) body mass index of 30.1 (9.1) kg/m. Patients with IH had thinner mean (SD) calvaria (3.01 [0.81] versus 2.70 [0.58] mm; p = 0.036) and skull bases (5.17 [1.22] versus 4.60 [1.42] mm; p = 0.043) when compared with patients without IH. The mean (SD) extracranial zygoma thickness was similar between the two groups (5.09 [0.76] versus 5.00 [0.73] mm; p = 0.56). General linear model regression demonstrated advancing age was associated with increasing calvarial thickness in patients without IH and calvarial thinning in patients with IH (p = 0.038).

CONCLUSION

IH is independently associated with intracranial bone (calvaria and skull base) thinning and not extracranial (zygoma) thinning. Skull thinning occurs with IH and advancing age. These findings support a possible role of increased ICP in the pathophysiologic development of spontaneous cerebrospinal fluid leaks.

Thinning or dehiscence of bone in structures of the middle cranial fossa floor in superior semicircular canal dehiscence

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is a rare inner ear disorder; currently, it is unknown whether the etiopathology underlying this structural irregularity affects neighboring structures. The goal is to investigate the prevalence of bone thinning in areas of the middle cranial fossa (MCF) floor in SSCD and non-SSCD patients.

METHODS

This retrospective study analyzed 100 patients from March 2011 to June 2017 at a tertiary referral center. 100 patients undergoing 118 SSCD repair surgeries (18 bilateral) were identified. 12 SSCD ears were excluded due to lack of pre-operative computed tomography (CT) scans or history of prior SSCD repair at an outside facility. Non-SSCD ears were identified from routinely-obtained CT scans for temporal bone fracture (fractured sides excluded) for a total of 101 ears; 26 non-SSCD ears were excluded due to lack of high-resolution imaging.

RESULTS

Univariate analyses reveal that SSCD diagnosis is associated with higher rates of geniculate ganglion (GG) dehiscence compared with non-SSCD controls (42.7 vs. 24%; χ²(1) = 9.69,P = 0.008). Individuals with SSCD depicted significantly thinner bone overlying the geniculate ganglion (GG) (0.23 ± 1.2 mm) compared to controls (0.28 ± 1.8 mm, (t(1 6 4)) = 2.1, P = 0.04). SSCD patients presented thinner bone overlying the internal auditory canal (IAC) (0.33 ± 1.3 mm) compared to patients without SSCD (0.46 ± 1.6 mm, (t(2 5 7) = 6.4, P < 0.001).

CONCLUSIONS

The increased prevalence of dehiscence of the MCF in this cohort of SSCD patients compared to non-SSCD patients suggests that the etiology underlying SSCD affects surrounding structures.

Is the Height of the Arcuate Eminence Related to Body Mass Index?

OBJECTIVES

To determine the relationship, if any, between body mass index (BMI) and attenuation of the arcuate eminence (AE).

STUDY DESIGN

Case series with chart review.

SETTING

Tertiary neurotologic referral center.

SUBJECTS AND METHODS

Submillimeter distances were recorded from high-resolution temporal bone computed tomography (CT) scans of 50 patients (100 sides). The AE (defined as the superiormost location of the petrous bone over the otic capsule), the bony apex of the superior semicircular canal (SSC), and the geniculate ganglion (GG) were identified and 3-dimensional distances measured. The height of the AE relative to the bony apex of the superior semicircular canal was determined using Euclidean geometry using the fixed anatomical landmark of the GG as the origin. Correlations between AE and BMI were calculated using Pearson's, linear mixed effects, and sensitivity analysis models.

RESULTS

The mean (SD) BMI was 30 (8.1) kg/m², with 16 (30%) patients falling in the underweight/normal category (BMI <25 kg/m²), 10 (20%) overweight patients (25 kg/m²≤ BMI ≤ 30 kg/m²), and 24 (48%) patients considered obese (BMI >30 kg/m²). The mean (SD) AE heights for the left and right ears were 2.5 (1.11) and 2.6 (1.09), respectively. The results of the linear mixed-effects models indicated little evidence that BMI is associated with AE height when including all patients (partial R² = 0.040) and when using BMI categories (partial R² = 0.025).

CONCLUSION

Contrary to other structures within the lateral skull base, the relative prominence of the arcuate eminence does not correlate with BMI or any other demographic variables.

The variation of superior semicircular canal bone thickness in relation to age and gender

BACKGROUND

Superior semicircular canal dehiscence syndrome (SSCD) is a current diagnosis that is due to a loss of bone covering the superior semicircular canal (SSC). This results in pressure-/sound- induced vertigo and oscillopsia.

OBJECTIVE

To find the variation of the thickness of the bone that covers the Superior Semicircular Canal with relation to age and gender among the Chinese descents.

MATERIALS AND METHODS

Three hundred and eleven temporal bone Cone Beam Computed Tomography (CBCT) images of patients who attended Otology clinic at Second Hospital of Shandong University from January, 2017 to April, 2018 were retrospectively studied. The images were reconstructed in the line of Poschl and the thinnest area of the bone covering the SSC was taken.

RESULTS

We included 172 (55.31%) females and 139 (44.69%) males. Mean age was 41 years. Overall mean difference in thickness was found to be -0.0210. There was no significant difference between the female and male bone thickness (p = .7113). With age the mean difference was 0.0801 (p = .1557) which was not statistically significant.

CONCLUSION AND SIGNIFICANCE

There was no significant change in bone thickness with advancing age. CBCT is the best method of assessing SSCD.

CT evaluation of normal bone thickness overlying the superior semicircular canal

Superior semicircular canal dehiscence (SSCD) is a rare inner ear disorder with variable amounts of auditory and vestibular dysfunction. In addition to the absence of bone overlying the superior semicircular canal, thinning of bone in this area can also initiate the vestibulocochlear symptoms of SSCD. We evaluated normal bone thickness overlying the course of the semicircular canal using computed tomography (CT) scans and assessed correlations between bone thickness and age, gender, and location of the thinnest bone. A single-institution retrospective chart review was conducted on 133 high-resolution CT scans from 76 healthy, asymptomatic patients between ages 9 and 96 years. These CT scans of the temporal bone were obtained between January 2012 and August 2017. The superior semicircular canal dome thickness at the apex was reported with a mean of 1.25 mm for all 76 patients; the 10th percentile was 0.60 mm, and the 90th percentile was 2.08 mm. The thinnest area of bone at any location yielded a mean of 0.86 mm. The normal bone thickness overlying the superior semicircular canal does not depend on gender or age. The thinnest location was evenly distributed across the superior semicircular canal. A bone thickness of 0.40 mm or greater was present in 90% of normal patients based on CT scan measurements at the thinnest location.

Radiologic correlation between the thickness of the roof of the glenoid fossa and that of the bony covering of the superior semicircular canal

OBJECTIVES

Dehiscence of the superior semicircular canal (SSC) has been associated with alteration of the temporomandibular joint, although data explaining this association are lacking. The present study examined the correlations between the presence of dehiscences and thickness of the bone covering the SSC and the roof of the glenoid fossa (RGF).

STUDY DESIGN

Computed tomography was used in a cross-sectional analysis of the presence of dehiscences and thickness of the bone overlying the SCC and RGF in 156 temporal bones of 78 patients. The correlations of the presence of dehiscences in the SSC and ipsilateral RGF and the thickness of bone covering the SSC and RGF were analyzed by using the χ² or Fisher's exact test. The relationship between the thickness of the bone overlying the SCC and RGF was analyzed by using the Spearman correlation coefficient and the Kruskal-Wallis test. The relationship between the thickness of the RGF and the covering of the SCC and patient age and gender was analyzed with the general linear model.

RESULTS

Significant correlations were found between the presence of dehiscences and thickness of the bone overlying the SSC and RGF (P < .001).

CONCLUSIONS

There is a morphologic relationship between the structure of the SSC and RGF.

Pediatric superior semicircular canal dehiscence: illustrative case and systematic review

OBJECTIVE The purpose of this study is to present an illustrative case of pediatric superior semicircular canal dehiscence (SSCD) and to systematically review the current published literature in the pediatric population. METHODS An electronic search of the Scopus, Web of Science, PsycINFO, Cochrane, and Embase databases was performed by 2 independent authors through January 2017. Search term combinations included "pediatrics," "children," "canal," and "dehiscence." Inclusion criteria were as follows: English, full-text clinical studies, case reports, and case series describing pediatric patient(s) (younger than 18 years) with CT evidence of SSCD. Baseline patient demographic characteristics, clinical presentations, dehiscence characteristics, management strategies, and outcome data were extracted. RESULTS A total of 14 studies involving 122 patients were included in the quantitative synthesis. The patients' mean age was 7.22 years. Male predominance was observed (approximate male-to-female ratio of 1.65:1). Neurodevelopmental disorders were common (n = 14, 11.5%). Auditory signs and symptoms were more common than vestibular signs and symptoms. Hearing loss (n = 62, 50.8%) was the most common auditory symptom and an indicator for imaging evaluation. Vertigo was the most common vestibular symptom (n = 8, 6.6%). Hearing aids were recommended in 8 cases (6.6%), and surgical repair was performed in 1 case (0.8%). Symptom outcomes and follow-up durations were infrequently reported. CONCLUSIONS The authors' data suggest that in pediatric SSCD, males are more commonly affected than females. This is different than the adult population in which females are predominantly affected. A history of otologic and/or neurodevelopmental abnormalities was common. There was a preponderance of auditory symptoms in this age group. Conservative management was favored in the majority.

Influence of Sex and Age on Posterior Semicircular Canal Thickness

OBJECTIVE

The aim of this study is to determine whether sex and age influence posterior semicircular canal (PSC) thickness.

METHODS

This observational study was conducted in 3 tertiary hospitals. The minimal distance between the PSC and the posterior cranial fossa (PSC thickness) was estimated by thin-section multidetector row computed axial tomography (CAT) scan of the temporal bones. Nonselected consecutive patients of all ages (607 temporal bones) were considered.

RESULTS

A significant effect was only detected for sex (F = 5.418, p = 0.020); PSC thickness showed a higher mean value in women (mean difference ± SE: 0.224 ± 0.096 mm). A significant and negative r value was detected for males aged >45 years (-0.173, p = 0.026); in that group of patients, PSC thickness decreased as age increased (0.018 ± 0.008 mm/year). For females aged ≤45 years, a significant and positive r value was found (0.198, p = 0.022); in that group, PSC thickness increased as age increased (0.020 ± 0.008 mm/year).

CONCLUSIONS

PSC thickness did not significantly evolve with age in young males (≤45 years) but it decreased from age 45 years onwards. On the other hand, PCS thickness increased with age in women until the age of 45 years and it did not significantly change in older females.

Outcomes of middle fossa craniotomy for the repair of superior semicircular canal dehiscence

Superior semicircular canal dehiscence (SSCD) is a rare defect of the arcuate eminence that causes an abnormal connection between the superior semicircular canal and middle cranial fossa. Patients often present with a variety of auditory and vestibular symptoms. Trigger avoidance is the initial strategy, but surgery may be necessary in debilitating cases. We retrospectively reviewed SSCD patients undergoing repair via a middle fossa craniotomy between March 2011 and September 2015. Forty-nine patients undergoing 58 surgeries were identified. Autophony was the most common symptom at presentation (n=44; 90%). Mean follow-up was 10.9months, with 100% of patients reporting resolution of at least one symptom. Aural fullness was the most commonly resolved symptom following surgical repair (n=19/22; 86%). Hearing loss (n=11/25; 44%) and tinnitus (n=11/38; 29%) were the most common symptoms to persist following surgery. The most common symptom to develop after surgery was disequilibrium (n=4/18; 22%). Upon comparing the overall pre-operative and post-operative groups, the number of patients with autophony (p<0.0001), aural fullness (p=0.0006), hearing loss (p=0.0119), disequilibrium (p=0.0002), sound- and pressure-induced vertigo (p<0.0001), and tinnitus (p<0.0001) were significantly different. Improved clinical outcomes were demonstrated in patients undergoing SSCD repair through a middle cranial fossa approach. The most common presenting symptom (autophony) was also most likely to resolve after surgery. Hearing loss is less amenable to surgical correction. Disequilibrium developed in a small number of patients after repair.

Síndrome da deiscência do canal semicircular superior: relato de dois casos

RESUMO A Síndrome da Deiscência do Canal Semicircular Superior (SDCSS) é caracterizada pelo desgaste da camada óssea que recobre o canal semicircular superior. São sintomas comuns da SDCSS a presença de vertigem associada à nistagmos induzidos por estímulos sonoros intensos ou por modificações das pressões intracraniana ou da orelha média. O objetivo deste trabalho é descrever os achados audiólogicos e vestibulares de dois pacientes com diagnóstico de Síndrome da Deiscência do Canal Semicircular Superior, com diagnóstico confirmado por meio de tomografia computadorizada. Foram realizadas meatoscopia, anamnese, audiometria tonal e vocal seguida das medidas de imitância acústica, Weber audiométrico, pesquisa do fenômeno de Túlio e manobra de Valsalva, realizados pela mesma pesquisadora em uma única sessão. Foram observados gap aéreo-ósseo, curva timpanométrica tipo A e reflexos acústicos presentes. O gap aéreo-ósseo apresenta-se com maior amplitude nas frequências baixas. As queixas auditivas não foram relatadas pelas pacientes como os primeiros sintomas. O Weber mostrou lateralização, nos dois casos, confirmando a presença de gap. O fenômeno de Túlio apresentou-se positivo para vertigem em ambos os casos. A manobra de Valsalva apresentou alteração em apenas um caso.

Lateral Skull Base Attenuation in Superior Semicircular Canal Dehiscence and Spontaneous Cerebrospinal Fluid Otorrhea

Objectives

(1) To quantitatively assess the lateral skull base thickness in patients with superior semicircular canal dehiscense (SSCD) using a standardized and validated radiographic measure and to compare it with that of a population with spontaneous cerebrospinal fluid otorrhea (CSFO). (2) To analyze demographic and clinical factors associated with skull base thickness in the SSCD group.

Study Design

Case series with chart review.

Setting

Tertiary neurotologic referral center.

Subjects and Methods

Based on computed tomography imaging of the tegmen, mean skull base thickness was calculated for 16 patients with radiographic and clinical SSCD. Similar measures were performed in 4 comparison groups consisting of adults with spontaneous CSFO (n = 33), as well as 3 control groups recruited from our adult cochlear implant database: 30 obese controls (body mass index [BMI] >30 kg/m2), 11 overweight controls (BMI, 25-30 kg/m2), and 20 normal weight controls (BMI <25 kg/m2).

Results

The SSCD group had a significantly lower mean BMI (28.6 kg/m2) than the spontaneous CSFO group (37.7 kg/m2; P = .0007). The mean skull base thickness of SSCD patients was 17% thinner than that of the CSFO group, 31% thinner vs obese controls, 49% thinner vs overweight controls, and 45% thinner vs normal weight controls. These differences were all statistically significant ( P < .05).

Conclusion

Patients with SSCD have a marked thinning of the lateral skull base, more so than patients with spontaneous CSF otorrhea and control groups with different BMIs. Skull base attenuation in SSCD patients did not correlate with BMI.

A radiologic and anatomic study of the superior semicircular canal

OBJECTIVES

The present study sought to determine whether there is a correlation between the prevalence of superior semicircular canal (SSC) dehiscence (SSCD) on temporal CT and population age. The secondary objective was to identify anatomic factors for SSCD by studying SSC diameter and its protrusion into the middle cranial fossa. The aim was to determine the acquired or congenital origin of SSCD (Minor's syndrome).

MATERIAL AND METHOD

A single-center retrospective radiological and anatomic study included 180 CT scans of 354 petrous parts of the temporal bone taken between January and December 2011 in a university hospital center. Bone thickness above the SSC was measured and classified in 4 grades: grade 1, >2.5mm; grade 2, <2.5mm: grade 3, predehiscent; grade 4, dehiscent. SSC diameter was also measured, as was the height of SSC protrusion into the middle cranial fossa.

RESULTS

SSCD was found in 0.8% of cases and predehiscence in 12%. Patients with dehiscence were older; patients with grade 3 or 4 were significantly older than those free of dehiscence (P<0.05). There was no significant difference in SSC diameter according to grade. In grade 1, protrusion was greater than in other subjects, with a significant correlation between age and reduced protrusion (P<0.05).

CONCLUSION

The study demonstrated a correlation between aging and SSCD prevalence. Reduced SSC roof height with age suggests that SSCD may be an acquired phenomenon, related in some way to aging of the base of the skull.

Superior canal dehiscence syndrome in children--a case report

Initially described in 1998, superior semicircular canal dehiscence syndrome (SCDS) has become a well-studied neurootologic entity in adults by now. Unfortunately, experience with children is limited and a diagnostic and therapeutic algorithm is lacking. The article therefore wants to provide an overview of the existing literature on superior semicircular canal dehiscence syndrome in children. Furthermore a diagnostic algorithm for daily clinical life based on a case report from an eleven-year-old girl is presented.

Assessment of superior semicircular canal thickness with advancing age

OBJECTIVE

To determine whether superior semicircular canal dehiscence (SSCD) is more prevalent with advancing age.

STUDY DESIGN

Retrospective observational study.

METHODS

High-resolution computed-tomographic temporal bone scans were identified for patients of all ages and analyzed by two independent assessors. Multiplanar reconstruction was applied, and the thinnest area of temporal bone overlying each superior semicircular canal (SSC) was measured.

RESULTS

A sample of 121 patients was analyzed that contained an almost identical number of male and female patients. In total, 242 temporal bone images were reviewed. Patients' ages ranged between 6 and 86 years. Age was shown to have a significant linear relationship (P < 0.001) such that for every unit increase in age the predicted thickness was reduced by 0.0047 mm.

CONCLUSIONS

The thickness of the SSC decreases with advancing age.

LEVEL OF EVIDENCE

4.

Radiographic features of superior semicircular canal dehiscence in the setting of chronic ear disease

OBJECTIVE

To determine if radiologic chronic otitis media (COM), both with and without cholesteatoma, is associated with superior semicircular canal dehiscence (SSCD).

STUDY DESIGN

Retrospective review of consecutive high-resolution computed tomography (HRCT) scans of the temporal bone.

SETTING

Tertiary care medical center.

PATIENTS

Two hundred consecutive patients undergoing HRCT of the temporal bone beginning January 1, 2012.

INTERVENTION

Imaging was evaluated by 3 reviewers (2 neuroradiologists and 1 neurotologist). All scans were assessed for the presence of SSCD, cholesteatoma, chronic otomastoiditis, tegmen dehiscence, and for abnormalities of the cochlea, vestibule, facial nerve, and temporal bone vasculature.

MAIN OUTCOME MEASURE

Ears with COM associated with chronic otomastoiditis or cholesteatoma were compared with those without COM with respect to the presence of SSCD or other temporal bone abnormalities. Statistical analysis was performed to assess for differences between the groups studied.

RESULTS

One-hundred ninety-four patients (388 ears) were included. Cholesteatoma was identified in 48 ears (12.4%) and chronic otomastoiditis in 62 ears (16%). Ten ears with cholesteatoma had ipsilateral SSCD, and 8 ears with chronic otomastoiditis had ipsilateral SSCD. In 340 ears without either cholesteatoma or chronic otomastoiditis, SSCD was found in 18 (5.3%). SSCD was found to occur significantly more often in patients with ipsilateral radiologic cholesteatoma. No cases of SSCD were associated with cochlear, facial nerve, or vascular abnormalities.

CONCLUSION

Our findings suggest that COM with cholesteatoma is associated with the presence of SSCD, although the nature of this association is unclear.