Third window lesions of the inner ear: A pictorial review.

PURPOSE: Radiographic review of pathologies that associate with third window syndrome. METHODS: Case series and literature review. RESULTS: Eight unique third window conditions are described and illustrated, including superior, lateral, and posterior semicircular canal dehiscence; carotid-cochlear, facial-cochlear, and internal auditory canal-cochlear dehiscence, labyrinthine erosion from endolymphatic sac tumor, and enlarged vestibular aqueduct. CONCLUSION: The present study highlights the characteristic imaging features and symptoms to differentiate third window pathologies for expedient diagnosis and management planning.

High jugular bulb with a diverticulum and vestibular aqueduct dehiscence: an anatomical variant to be aware in patients with hearing loss.

PURPOSE: To describe an anatomical variant that should be consider in patients with hearing loss. METHODS: An 8-year-old girl underwent to temporal bone computed tomography for the evaluation of bilateral conductive hearing loss and further assessment of possible enlarged vestibular aqueduct or high jugular bulb on brain magnetic resonance imaging (MRI). RESULTS: CT of temporal bone showed a cystic cavity with bony sclerotic margins extending from the right jugular foramen to the vestibular aqueduct. Bony dehiscence of the jugular foramen with the right carotid canal was also noted. On brain MRI, there was no evidence of enlargement of the endolymphatic duct and sac on T2 thin-section gradient echo sequence. Time of flight MR angiography did not show arterial flow in the cavity. Contrast enhanced MR venography confirmed the presence of a high right jugular bulb with a diverticulum extending into the vestibular aqueduct due to jugular bulb-vestibular aqueduct dehiscence. CONCLUSION: Knowledge of high jugular bulb-vestibular aqueduct dehiscence is important in the assessment of patients with otologic symptoms such as vertigo, tinnitus and hearing loss.

Vestibular Aqueduct Size Correlates With the Degree of Cochlear Hydrops in Patients With and Without Menière's Disease.

OBJECTIVE: To correlate the CT imaging findings of the visibility and size of the vestibular aqueduct (VA) with the degree of the cochlear hydrops determined in MRI late imaging of the hydrops. Study Design: Retrospective study. Setting: Tertiary referral center. Patients: A total of 127 patients (62 women, 65 men, average age 55.6 yrs): 86 of these were diagnosed with Menière's disease (American Academy of Otolaryngology-Head and Neck Surgery [AAO-HNS] criteria; 67 unilateral, 19 bilateral). INTERVENTIONS: Temporal bone CT and hydrops MRI were performed in all patients. MAIN OUTCOME MEASURES: Visibility/width of the VA in temporal bone CT and grade of cochlear hydrops evaluated by MRI. RESULTS: The width of the VA is significantly smaller in patients diagnosed with Menière's disease (30% non-visible VA), compared with the patients who did not fulfill the diagnostic criteria of Menière's disease (12% non-visible VA) (double sided Spearman correlation, p < 0.001). In all ears of patients diagnosed with Menière's disease the width of the VA was significantly correlated with the degree of the cochlear hydrops (in cases of non-visible VA 65% [34/52] ears presented with hydrops grade 3 or 4; 13% [7/52] ears presented with hydrops grade 1 or 2 and 21% [11/52] ears showed no hydrops) (Spearman correlation p = 0.001/p < 0.01). This is also true for all ears that can be summarized as hydrophic ear disease (symptomatic ears that present with a hydrops in MRI). CONCLUSIONS: The results of our study could confirm the importance of the VA in the pathogenesis of the endolymphatic hydrops in vivo.

Cochlear implantation in a 10-year old boy with Pendred syndrome and extremely enlarged endolymphatic sacs.

A 10-year-old boy with fluctuating sensorineural hearing loss (SNHL) and biallelic mutations in the SLC26A4 gene and with inner ear anomalies received a cochlear implantation. SLC26A4 mutations are associated with variable degrees of SNHL and enlarged vestibular aqueducts (EVA), identified either as non-syndromic EVA or classic Pendred syndrome; the latter also associated with thyroid dysfunction. The inner ear malformations in this group of patients have been considered a relative contraindication against cochlear implantation because of the potential per- and postoperative complications such as peroperative cerebrospinal fluid leak or postoperative vestibular symptoms. In the current case there were no surgical or postoperative complications, indicating that extremely enlarged endolymphatic sacs are not as such a contraindication for cochlear implantation. This case also illustrates the management dilemma of an appropriate timing for cochlear implantation.

Another evidence for pressure transfer mechanism in incomplete partition two anomaly via enlarged vestibular aqueduct.

A female patient with unilateral enlarged vestibular aqueduct (EVA) demonstrated scala vestibuli dilatation on that side while on the contralateral side both vestibular aqueduct and scala vestibuli were normal. This important radiological finding demonstrates that modiolar defects (hence 'cystic apex') observed in Incomplete partition-II is due to pressure transfer via EVA during embryological development. Therefore, it supports the previous histopathological ideas radiologically. Depending on the patency of EVA, variety of modiolar defects may arise.

Anatomical Variations in Patients with Ménière Disease: A Tomography Study

Abstract Introduction The etiology of Ménière disease (MD), a difficult-to-treat condition with great morbidity, remains controversial in the literature. The possible clinical and diagnostic impact of anatomical variations of the temporal bone among patients with MD has been recently studied. Objective To identify anatomical variations of the temporal bone associated with the diagnosis of MD. Methods Thirty-seven patients were included, although each ear was considered separately (n = 74). A case group (nA = 33) was composed of the affected ears of patients with definiteMDand a control group (nB = 41) was used consisting of the ears of individuals who did not meet the criteria for MD and of the contralateral ears from patients with unilateral disease. Tomographic images from the individuals included in the study were submitted to a blinded and systematic evaluation regarding a broad variety of anatomical variations of the temporal bone. Obtained data were compared statistically between the groups and after stratifying the study sample. Significance level was set at 0.05. Results Among the affected ears, it was observed an increased number of tomographic scans in which the vestibular aqueduct could not be identified (p = 0.01, Fisher exact test). No statistically significant differences were observed when comparing the affected and contralateral ears frompatients with unilateral MD, between affected ears from patients with unilateral and bilateral disease or between contralateral ears of patients with unilateral affection and patients without the disease. Conclusion Some anatomical variations might be more frequent in the affected ears of patients with MD, such as the lower rates of individualization of the vestibular aqueduct.

Endoscopic assistance in retrosigmoid transmeatal approach to intracanalicular vestibular schwannomas - An alternative for middle fossa approach. Technical note.

BACKGROUND: Complete surgical removal of intracanalicular vestibular schwannomas with nerve VII and VIII sparing and without worsening patient's status is challenging. Also the choice of an optimal surgical technique, which is usually limited to selection between retrosigmoid transmeatal (RT) and middle fossa (MF) approach, can be a challenge. Although many previous studies documented superiority of RT to MF approach and vice versa, still no consensus has been reached regarding an optimal approach to intracanalicular vestibular schwannomas. In this technical note, we present RT approach with an endoscopic assistance and highlight its advantages over MF approach in surgical management of pure intracanalicular vestibular schwannomas. METHOD: RT approach with an endoscopic assistance is presented as an optimal surgical treatment for intracanalicular vestibular schwannomas, and its advantages are compared to those offered by MF approach. RESULTS: Under an endoscopic guidance, we found a residual tumor in the fundus of the inner acoustic canal and performed its gross total resection. CONCLUSIONS: RT approach is an excellent technique suitable for safe radical surgical treatment of T1 vestibular schwannomas; this technique is associated with lower morbidity risk than MF approach.

[HRCT and MRI image of bilateral large vestibular aqueduct syndrome].

OBJECTIVE: To explore. HRCT and MRI three-dimensional fast imaging employing steady state ac-quisition(3D-FIESTA) imaging features and clinical characteristics of bilateral large vestibular aqueduct syndrome(LVAS). METHOD: The imaging and clinical features of 14 cases of bilateral LVAS identified over a 5-year periodwere retrospectively analyzed. All patients underwent HRCT and MRI 3D-FIESTA scanning of head and neck;MRI three dimensional reconstructions of internal acoustical meatus were also completed at the same time. RESULT: Audiogram showed mild to moderate hearing loss and was progressive. The cut-off values for the coronal midpointand operculum planes on the HRCT scan to diagnose an EVA were 1. 5 mm and 4. 3 mm respectively; the averagevalue was 2. 4 mm. VA expansion degree were not linked to the degree of hearing loss. MRI showed VA andlymph sac abnormalities. Concomitant image finding was cochlear hypoplasia. CONCLUSION: HRCT and MRI 3D-FI-ESTA are important examinations for accurate diagnosis of LVAS. HRCT can acquire the specific size of reamedVA. MRI and 3D reconstructions of internal acoustical meatus can noninasive show more intuitive display ofLVAS and other inner ear malformations than HRCT.

[The research progress of unilateral enlargement of the vestibular aqueduct].

Unilateral enlargement of the vestibular aqueduct (EVA)is a relatively rare disease. Bilateral EVA was found to be more common than unilateral EVA. There are significant differences in clinical features and molecular etiology between unilateral EVA and bilateral one. This article reviewed related researches of the unilateral EVA in clinical characteristics, molecular etiology and pathogenic mechanism.

[The application value of MRI in the children with sensorineural hearing loss before cochlear implantation].

OBJECTIVE: To investigate diagnostic value and clinical application of MRI in the children with sensorineural hearing loss (SNHL) before cochlear implantation. METHOD: MRI images of 80 children with the diagnosis of SHNL were retrospectively analyzed in combination with the latest classification of inner ear malformation. RESULT: There were 152 ears of inner ear malformation of 80 cases (160 ears), including 38 ears of cochlear malformation, 33 ears of vestibular malformation, 41 ears of semicircular canal malformation, 37 ears of vestibular aqueduct enlargement, 40 ears of internal auditory canal malformation, and 46 ears of cochlear nerve malformation. CONCLUSION: MRI can provide detailed and reliable anatomical information for children with SNHL before cochlear implantation, and help to make the classification diagnosis. Therefore MRI is of great clinical significance for operation plan guidance and prognosis assessment.

Correlation between genotype and phenotype in patients with bi-allelic SLC26A4 mutations.

Mutation of SLC26A4 is the most common cause of prelingual hearing loss in East Asia. Patients with SLC26A4 mutations have variable phenotypes ranging from non-syndromic hearing loss to Pendred syndrome. Here, we analyzed the correlation between genotype and various inner ear phenotypes and found a possible underlying mechanism. This study included 111 patients with bi-allelic SLC26A4 mutations who had bilateral enlarged vestibular aqueduct (EVA) and hearing loss. p.H723R (61%), c.919-2A>G (24%), and p.T410M (4%) were the most common mutations in Korean patients with EVAs. Residual hearing in patients with c.919-2A>G or p.T410M mutations was better than that of patients with p.H723R homozygous mutations. Interestingly, quantitative polymerase chain reaction showed normal pendrin transcript (6-17% of normal levels) was produced from patients with c.919-2A>G homozygous mutations. Surface expression ratio of pendrin and residual anion exchange activity were higher in cells transfected with p.T410M in comparison to cells transfected with p.H723R. These results suggest that there is a correlation between degree of residual hearing and the SLC26A4 genotype commonly found in the East Asian population.

Use of SLC26A4 mutation testing for unilateral enlargement of the vestibular aqueduct.

IMPORTANCE: Approximately one-half of all subjects with unilateral or bilateral hearing loss with enlargement of the vestibular aqueduct (EVA) will have SLC26A4 gene mutations. The number (0, 1, or 2) of mutant alleles of SLC26A4 detected in an individual subject with EVA is each associated with a distinct combination of diagnostic and prognostic information as well as probability of recurrence of EVA in siblings. OBJECTIVE: To evaluate the results of SLC26A4 mutation testing in subjects with unilateral EVA. (The study objective was formulated before data were collected.) DESIGN: Prospective cross-sectional study of cohort ascertained between 1998 and 2012. SETTING: National Institutes of Health Clinical Center, a federal biomedical research facility. PARTICIPANTS: Twenty-four subjects (10 males, 14 females) with unilateral EVA, defined as a midpoint diameter greater than 1.5 mm, who were referred or self-referred to participate in a study about the clinical and molecular analysis of EVA. Twenty-one (87.5%) of 24 subjects were white. Mean age was 10.3 years (age range, 5-39 years). INTERVENTION: SLC26A4 mutation analysis. MAIN OUTCOMES AND MEASURES: Audiometric results, the presence or absence of EVA, and the number of mutant alleles of SLC26A4. RESULTS: Approximately 8.3% of the subjects with unilateral EVA had 2 mutant SLC26A4 alleles, 16.7% had 1 mutant allele, and 75.0% had 0 mutant alleles. CONCLUSIONS AND RELEVANCE: Unilateral EVA can be associated with all possible SLC26A4 genotype results. The distinct combination of prognoses and recurrence probability associated with each genotype supports the clinical use of testing for SLC26A4 mutations in subjects with unilateral EVA.

Lack of significant association between mutations of KCNJ10 or FOXI1 and SLC26A4 mutations in Pendred syndrome/enlarged vestibular aqueducts.

BACKGROUND: Pendred syndrome is a common autosomal recessive disorder causing deafness. Features include sensorineural hearing impairment, goitre, enlarged vestibular aqueducts (EVA) and occasionally Mondini dysplasia. Hearing impairment and EVA may occur in the absence of goitre or thyroid dyshormonogensis in a condition known as non-syndromic EVA. A significant number of patients with Pendred syndrome and non-syndromic EVA show only one mutation in SLC26A4. Two genes, KCNJ10, encoding an inwardly rectifying potassium channel and FOXI1, a transcriptional factor gene, are thought to play a role in the disease phenotypes. METHODS: Using Polymerase Chain Reaction and Sanger sequencing, sixty-eight patients with monoallelic mutations of SLC26A4 were tested for mutations in KCNJ10 and FOXI1. RESULTS: Two variants were observed in the KCNJ10 gene, p.Arg271Cys in three patients and p.Arg18Gln in one patient; only one variant, p.Arg123Trp was observed in the FOXI1 gene in a single patient. Both p.Arg271Cys and p.Arg18Gln are likely to be polymorphisms as judged by their frequency in the general population. CONCLUSION: Therefore we found no evidence for a significant association between mutations of KCNJ10 and FOXI1 with SLC26A4. It was also observed that the variant, p.Arg271Cys in KCNJ10, previously thought to have a protective effect against seizure susceptibility, was found in a patient with Pendred syndrome with co-existing epilepsy.

Bilateral enlarged vestibular aqueduct with associated bilateral Mondini's dysplasia.

Enlarged Vestibular Aqueduct (EVA) and Mondini's dysplasia (incomplete partitioning type II) are entitites that have been fairly well described in the literature as potential causes of hearing loss in the young. However, it is uncommon for this condition to be detected bilaterally, especially so for both conditions to coexist bilaterally in the same patient. This is a brief description of a patient with the above bilateral condition with attached high resolution CT scan images of the temporal bone to illustrate the case.

A clinical and histopathologic study of jugular bulb abnormalities.

OBJECTIVE: To further define the spectrum of clinical presentation and explore the histologic sequelae of jugular bulb abnormalities (JBAs). DESIGN: Retrospective review. SETTING: Academic medical center. PATIENTS: Thirty patients with radiologic evidence of inner ear dehiscence by JBA. MAIN OUTCOME MEASURE: Thirty patients with radiologic inner ear dehiscence by JBA and 1579 temporal bone specimens were evaluated for consequences from JBA. RESULTS: We found that JBA-associated inner ear dehiscence could be identified on computed tomography of the temporal bone but not on magnetic resonance imaging scan. Jugular bulb abnormalities eroded the vestibular aqueduct most often (in 25 patients), followed by the facial nerve (5 patients) and the posterior semicircular canal (4 patients). Half of the patients (15) were asymptomatic. Results from vestibular evoked myogenic potential (VEMP) tests were positive in 8 of 12 patients with inner ear dehiscence. Histologically, only 2 of 41 temporal bones with dehiscence of the vestibular aqueduct demonstrated endolymphatic hydrops. CONCLUSIONS: Jugular bulb abnormalities can erode into the vestibular aqueduct, facial nerve, and the posterior semicircular canal. While symptoms may include pulsatile tinnitus, vertigo, or conductive hearing loss, in contrast to earlier reports, half of the patients were asymptomatic. Dehiscence of vestibular aqueduct rarely leads to clinical or histologic hydrops. The VEMP testing was useful in confirming the presence of inner ear dehiscence due to JBAs. Because the natural history of JBAs is unknown, these patients should be followed closely to evaluate for progression of the JBA or development of symptoms.

The relationship between jugular bulb-vestibular aqueduct dehiscence and hearing loss in pediatric patients.

OBJECTIVE: To determine the prevalence of jugular bulb and vestibular aqueduct dehiscence (JBVAD) in pediatric patients undergoing temporal bone computed tomography (CT) scans and to assess the relationship between JBVAD and hearing loss. STUDY DESIGN: Cross-sectional study with chart review. SETTING: Tertiary academic medical center. SUBJECTS AND METHODS: All patients 18 years of age or younger who had undergone temporal bone CT scans and audiometric testing between 2004 and 2009 were retrospectively reviewed. JBVAD was determined by blinded review of CT images. Hearing loss was determined by review of audiometric data and was correlated with imaging findings. RESULTS: CT images and audiometric data were available for review in 927 patients (1854 ears). Overall prevalence of JBVAD was 8.6%, with a prevalence of 6.6% in right ears and 3.6% in left ears. JBVAD was present in 8.3% and 7.1% of patients with and without sensorineural or mixed hearing loss, respectively (95% confidence interval [CI], -2.3% to 4.6%; P = .51). Similarly, JBVAD was present in 5.5% of ears with and 4.6% of ears without sensorineural or mixed hearing loss (95% CI, -1.1% to 2.9%; P = .37). CONCLUSION: The prevalence of JBVAD is 8.6% in pediatric patients undergoing temporal bone CT scans, 65% of which occur in the right ear. We were unable to identify any relationship between JBVAD and hearing loss. A major contribution to pediatric sensorineural hearing loss from JBVAD is therefore extremely unlikely.

Spectrum and frequency of SLC26A4 mutations among Czech patients with early hearing loss with and without Enlarged Vestibular Aqueduct (EVA).

Mutations in SLC26A4 cause Pendred syndrome (PS) - hearing loss with goitre - or DFNB4 - non-syndromic hearing loss (NSHL) with inner ear abnormalities such as Enlarged Vestibular Aqueduct (EVA) or Mondini Dysplasia (MD). We tested 303 unrelated Czech patients with early hearing loss (298 with NSHL and 5 with PS), all GJB2-negative, for SLC26A4 mutations and evaluated their clinical and radiological phenotype. Among 115 available HRCT/MRI scans we detected three MD (2.6%), three Mondini-like affections (2.6%), 16 EVA (13 bilateral - 19.2% and 15.6% respectively) and 61 EVA/MD-negative scans (73.4%). We found mutation(s) in 26 patients (8.6%) and biallelic mutations in eight patients (2.7%) out of 303 tested. In 18 of 26 (69%) patients, no second mutation could be detected even using MLPA. The spectrum of SLC26A4 mutations in Czech patients is broad without any prevalent mutation. We detected 21 different mutations (four novel). The most frequent mutations were p.Val138Phe and p.Leu445Trp (18% and 8.9% of pathogenic alleles respectively). Among 13 patients with bilateral EVA, six patients (50%) carry biallelic mutations. In EVA -negative patients no biallelic mutations were found but 4.9% had monoallelic mutations. SLC26A4 mutations are present mostly in patients with EVA/MD and/or progressive HL and those with affected siblings.

Mutation analysis of SLC26A4 in mainland Chinese patients with enlarged vestibular aqueduct.

OBJECTIVE: We have characterized the spectrum of SLC26A4 mutations and clinical features in a population of mainland Chinese patients with nonsyndromic sensorineural hearing loss (SNHL) and enlarged vestibular aqueduct (EVA). STUDY DESIGN: Cross-sectional clinical genetic study. SETTING: Tertiary care outpatient otolaryngology clinic. METHODS: A total of 32 subjects identified with bilateral EVA using high-resolution CT were screened for mutations in SLC26A4 by denaturing high-performance liquid chromatography and direct sequencing methods. RESULTS: A total of 13 different mutations were identified in the SLC26A4 gene, five of which are novel. A total of 88 percent of the patients harbored biallelic mutations, 11 patients were homozygotes, and 17 were compound heterozygotes. Four patients were found to carry a single SLC26A4 mutation. The IVS7-2A>G mutation was the most frequent, accounting for 60 percent of the mutant alleles. We have not found any correlations between the type of SLC26A4 mutations and the type, degree, and progression of hearing loss. There are significant proportions of patients with asymmetric (26%), progressive (32%), or fluctuating hearing loss (21%). CONCLUSION: Our data confirm the high prevalence of SLC26A4 mutations in Chinese patients with SNHL and EVA. We could not establish any relationship between genotype and phenotype. However, the high incidence of asymmetric, progressive, and fluctuating hearing loss found in the current study indicates that patients with those features should be routinely screened for SLC26A4 mutation in addition to diagnosis of EVA using CT or MRI.

Evaluation of the thyroid in patients with hearing loss and enlarged vestibular aqueducts.

OBJECTIVE: To evaluate thyroid structure and function in patients with enlargement of the vestibular aqueduct (EVA) and sensorineural hearing loss. DESIGN: Prospective cohort survey. SETTING: National Institutes of Health Clinical Center, a federal biomedical research facility. PATIENTS: The study population comprised 80 individuals, aged 1.5 to 59 years, ascertained on the basis of EVA and sensorineural hearing loss. MAIN OUTCOME MEASURES: Associations among the number of mutant alleles of SLC26A4; volume and texture of the thyroid; percentage of iodine 123 ((123)I) discharged at 120 minutes after administration of perchlorate in the perchlorate discharge test; and peripheral venous blood levels of thyrotropin, thyroxine, free thyroxine, triiodothyronine, thyroglobulin, antithyroid peroxidase and antithyroglobulin antibodies, and thyroid-binding globulin. RESULTS: Thyroid volume is primarily genotype dependent in pediatric patients but age dependent in older patients. Individuals with 2 mutant SLC26A4 alleles discharged a significantly (P < or = .001) greater percentage of (123)I compared with those with no mutant alleles or 1 mutant allele. Thyroid function, as measured by serologic testing, is not associated with the number of mutant alleles. CONCLUSIONS: Ultrasonography with measurement of gland volume is recommended for initial assessment and follow-up surveillance of the thyroid in patients with EVA. Perchlorate discharge testing is recommended for the diagnostic evaluation of patients with EVA along with goiter, nondiagnostic SLC26A4 genotypes (zero or 1 mutant allele), or both.

Enlarged vestibular aqueduct in pediatric sensorineural hearing loss.

OBJECTIVE: Comparison of the Cincinnati criteria (midpoint >0.9 mm or operculum >1.9 mm) to the Valvassori criterion (midpoint > or =1.5 mm) for enlarged vestibular aqueduct (EVA) in pediatric cochlear implant patients. STUDY DESIGN: Cohort study. SUBJECTS: One hundred thirty pediatric cochlear implant recipients. METHODS: We reviewed temporal bone CT scans to measure the vestibular aqueduct midpoint and opercular width. RESULTS: The Cincinnati criteria identified 44 percent of patients with EVA versus 16 percent with the Valvassori criterion (P < 0.01). Of those with EVA, 45 percent were unilateral and 55 percent were bilateral using Cincinnati criteria; 64 percent were unilateral and 36 percent bilateral using Valvassori criterion (P < 0.01). The Cincinnati criteria diagnosed 70 ears with EVA classified as normal using the Valvassori criterion (P < 0.01); 59 lacked another medical explanation for their hearing loss. CONCLUSION: The Cincinnati criteria identified a large percentage of pediatric cochlear implant patients with EVA who might otherwise have no known etiology for their deafness.