Ear Dehiscence Research Articles

Iatrogenic inner ear dehiscence associated with lateral skull base surgery: a systematic analysis of drilling injuries and their causal factors.

Drilling injuries of the inner ear are an underreported complication of lateral skull base (LSB) surgery. Inner ear breaches can cause hearing loss, vestibular dysfunction, and third window phenomenon. This study aims to elucidate primary factors causing iatrogenic inner ear dehiscences (IED) in 9 patients who presented to a tertiary care center with postoperative symptoms of IED following LSB surgery for vestibular schwannoma, endolymphatic sac tumor, Meniere's disease, paraganglioma jugulare, and vagal schwannoma. Utilizing 3D Slicer image processing software, geometric and volumetric analysis was applied to both preoperative and postoperative imaging to identify causal factors iatrogenic inner ear breaches. Segmentation analyses, craniotomy analyses, and drilling trajectory analyses were performed. Cases of retrosigmoid approaches for vestibular schwannoma resection were compared to matched controls. Excessive lateral drilling and breach of a single inner ear structure occurred in 3 cases undergoing transjugular (n=2) and transmastoid (n=1) approaches. Inadequate drilling trajectory breaching ≥1 inner ear structure occurred in 6 cases undergoing retrosigmoid (n=4), transmastoid (n=1), and middle cranial fossa approaches (n=1). In retrosigmoid approaches the 2-cm visualization window and craniotomy limits did not provide drilling angles to the entire tumor without causing IED in comparison to matched controls. Inappropriate drill depth, errant lateral drilling, inadequate drill trajectory, or a combination of these led to iatrogenic IED. Image-based segmentation, individualized 3D anatomical model generation, and geometric and volumetric analyses can optimize operative plans and possibly reduce inner ear breaches from lateral skull base surgery.

Comparison of radiological abnormalities between the jugular bulb and the vestibular aqueduct in patients with Ménière's disease.

Anatomical variations of the inner ear may contribute to the development of Ménière's disease (MD), which is a complex inner ear disorder histopathologically characterized by idiopathic endolymphatic hydrops (ELH). Abnormalities of the vestibular aqueduct (VA) and the jugular bulb (JB) have been suggested as predisposing factors. Yet, few studies have investigated the correlation between JB abnormalities and VA variations as well as its clinical relevance in these patients. In this retrospective study, we investigated the differences in the incidence of radiological abnormalities of the VA and JB in patients with definite MD. Anatomical variations of JB and VA were evaluated based on high-resolution CT (HRCT) in a series of 103 patients with MD (93 unilateral cases and 10 bilateral cases). JB-related indices included JB anteroposterior and mediolateral diameter, JB height, JB type regarding to Manjila classification system, and incidences of JB diverticulum (JBD), JB related inner ear dehiscence (JBID), and inner ear adjacent JB (IAJB). VA-related indices included CT-VA visibility, CT-VA morphology (funnel, tubular, filiform, hollow, and obliterated-shaped type), and peri-VA pneumatization. Radiological indices were compared between MD ears and control ears. Radiological JB abnormalities were comparable between MD ears and control ears. As for VA-related indices, the CT-VA visibility was lower in MD ears than in control ears (p = 0.004). The distribution of CT-VA morphology was significantly different between MD and control ears (p = 0.013), with a higher proportion of obliterated-shaped type in MD ears (22.1%) than in control ears (6.6%). Compared with JB abnormalities, the anatomical variations of VA are more likely to be an anatomically predisposing factor for MD.

Iatrogenic Inner Ear Dehiscence after Skull Base Surgery: Treatment Quandary

Iatrogenic Inner Ear Dehiscence after Skull Base Surgery: Treatment Quandary

The Prevalence of High-Riding Jugular Bulb in Patients with Suspected Endolymphatic Hydrops.

Background To determine the prevalence of a high-riding jugular bulb (HRJB) in the endolymphatic hydrops population. Methods This was a retrospective chart and radiology review of patients seen at a tertiary care medical center. Patients were identified using the International Classification of Diseases, 9th edition, code 386.xx (Meniere disease-unspecified), and were required to have undergone an imaging study that included views of the jugular bulb that were available for review. A radiologist then evaluated all of the imaging studies for evidence of HRJB or inner ear dehiscence with a jugular bulb abnormality. Results The prevalence of a HRJB in all endolymphatic hydrops patients was 9.0% (7 of 78), and it was 4.5% (7 of 156) in all ears. The prevalence of HRJB ipsilateral to an ear with endolymphatic hydrops was 4.6% (4 of 88 ears); it was 4.4% (3 of 68 ears) in ears without endolymphatic hydrops. The incidence of inner ear dehiscence with a HRJB was 1.3% (1 of 78). Electrocochleography results were not correlated with jugular bulb volume. Discussion The results of this study indicate that a small subset of patients treated for endolymphatic hydrops patients have a HRJB. Overall, these results suggest that HRJB does not play a major role in endolymphatic hydrops, although it may play a role in a few isolated patients.

The relationship between jugular bulb position and jugular bulb related inner ear dehiscence: a retrospective analysis

ObjectiveHigh jugular bulb (HJB) can erode inner ear structures creating a jugular bulb related inner ear dehiscence (JBID). The aim of this study was to analyze the relationship between the position of jugular bulb (JB) and JBID using high-resolution computed tomography (HRCT). Material and methodsIn this retrospective study HRCT images of 552 ears of 276 patients with hearing loss, otogenic vertigo, tinnitus or idiopathic peripheral facial nerve paralysis were analyzed. HJB type-1 was defined when JB dome reached above the inferior part of the round window, but was below the inferior edge of the internal acoustic meatus (IAM). HJB type-2 was defined when the dome of JB was higher than the inferior edge of IAM. The frequencies and types of HJB were evaluated. JBID for each HJB type was determined. Frequencies of JBID eroding the vestibular aqueduct (VA), the cochlear aqueduct and the posterior semicircular canal were examined. ResultsHJB type-1 and HJB type-2 were found in 19% (105/552) and in 15.8% (87/552) of studied ears. JBID showed to be in 3.8% (21/552) of all ears. 90.5% (19/21) of JBID revealed eroding of VA. Jugular bulb related cochlear aqueduct dehiscence and jugular bulb related posterior semicircular canal dehiscence were found in one ear each. The frequency of jugular bulb related vestibular aqueduct dehiscence (JBVAD) in patients with HJB reaching above IAM was higher than in patients with HJB lower than IAM. ConclusionsHJB is common, but JBID is rare. JBID prevalently erodes VA. HJB rising above IAM is most at risk to show JBVAD.

Perilymphatic fistula of the round window after whiplash injury: another cause of inner ear conductive hearing loss

Perilymphatic fistula is usually associated with sudden or fluctuating sensorineural hearing loss. We present a case of whiplash injury in a patient who showed conductive hearing loss at low frequencies due to a perilymphatic fistula occurring in the round window. Although no middle ear pathology was found, the symptoms and laboratory findings were mimicking the so called “third mobile window” phenomenon, but without the presence of inner ear dehiscence. Following early surgical exploration with patching of the round window the hearing was restored and the patient was free of symptoms.

Jugular bulb abnormalities in patients with Meniere’s disease using high-resolution computed tomography

Temporal bone abnormalities such as hypoplasia of the vestibular aqueduct or hypopneumatization of the mastoid have been described in Meniere's disease (MD). Jugular bulb abnormalities (JBA) are one of the most common temporal bone abnormalities. The aim of this study was to evaluate the frequency of JBA in MD. Radiological data obtained by temporal bone high-resolution computed tomography of 200 ears of 167 MD patients (MD group) and 218 ears of 109 patients with normal inner ear function (control group) were analyzed retrospectively. The frequencies of high jugular bulb (HJB), jugular bulb diverticulum (JBD), inner ear adjacent jugular bulb (IAJB) and jugular bulb related inner ear dehiscence (JBID) were evaluated and compared between MD group and control group. IAJB was differentiated into vestibular aqueduct adjacent jugular bulb (VAAJB), cochlear aqueduct adjacent jugular bulb and posterior semicircular canal adjacent jugular bulb. JBID was further analyzed by differentiating into jugular bulb related vestibular aqueduct dehiscence (JBVAD), jugular bulb related cochlear aqueduct dehiscence and jugular bulb related posterior semicircular canal dehiscence. The frequencies of HJB, JBD and IAJB were higher in MD group compared to control group (21, 13.3 %, p = 0.036; 8.5, 3.7 %, p = 0.037; 13.5, 4.6 %, p = 0.001). No differences between both groups were seen in JBID (4.0, 2.3 %, p = 0.315). Most IAJB and JBID were seen in VAAJB and JBVAD. There is a higher frequency of JBA in patients with MD than in patients without inner ear symptoms. Temporal bones of MD patients might be constituted anatomically different, carrying predisposing factors for the development of clinically apparent MD.

Prevalence of Jugular Bulb Abnormalities and Resultant Inner Ear Dehiscence

Jugular bulb abnormalities (JBA), including high-riding jugular bulb (HRJB) and jugular bulb diverticulum (JBD), can erode into the inner ear. In this study, the authors investigate the prevalence and consequences of JBA and their erosion into inner ear structures using temporal bone histopathology and computed tomography (CT). Cross-sectional study of temporal bone histopathology and radiology. Academic medical center. In total, 1579 temporal bone specimens and 100 CT of the temporal bones (200 ears) were examined for JBA and any associated dehiscence of inner ear structures. Temporal bone specimens were examined for histological consequences of inner ear erosion. Jugular bulb dimensions were measured on axial CT scans and compared across groups. Accompanying demographic and clinical information were reviewed. High jugular bulbs were noted in 8.2% (130/1579) of temporal bone specimens and in 8.5% (17/200) of temporal bone CT. The prevalence of JBA increases during the first 4 decades of life and stabilizes thereafter. High-riding jugular bulbs eroded inner ear structures such as the vestibular aqueduct, vertical facial nerve, or posterior semicircular canal in 2.8% (44/1579) of cases histologically and 1.5% (3/200) radiologically. In most, jugular bulb-mediated inner ear dehiscence was clinically and radiologically silent. Jugular bulb abnormalities are common. They are present in 10% to 15% individuals and are primarily acquired by the fourth decade of life. In 1% to 3% of cases, the HRJB erodes into the inner ear and most frequently involves the vestibular aqueduct.

A Clinical and Histopathologic Study of Jugular Bulb Abnormalities

To further define the spectrum of clinical presentation and explore the histologic sequelae of jugular bulb abnormalities (JBAs). Retrospective review. Academic medical center. Thirty patients with radiologic evidence of inner ear dehiscence by JBA. Thirty patients with radiologic inner ear dehiscence by JBA and 1579 temporal bone specimens were evaluated for consequences from JBA. 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. 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.

Prevalence of Jugular Bulb Abnormalities and Resultant Inner Ear Dehiscence: a Histopathologic and Radiologic Study

Objective: Jugular bulb (JB) abnormalities including high riding JB and JB diverticulum can erode inner ear structures and cause hearing loss, dizziness, and tinnitus. This study investigates 1) the prevalence of JB abnormalities, and 2) their erosion into inner ear structures using temporal bone histopathology and computed tomography (CT). Method: A total of 1579 temporal bones and 100 CT of the temporal bones (200 ears) were reviewed. The presence of a high JB was recorded as was its erosion into inner ear structures. Accompanying demographic and clinical information was reviewed. Results: High JB was noted in 8.2% (130/1579) of temporal bone specimens, and in 8.5% (17/200) of cases radiologically. Histologically, high JB were more common on the left side, in women, and in those greater than 40 years old. There was no significant increase in the prevalence of high JB over age 40 years. High JB eroded inner ear structures in 34% (44/130) of cases histologically and 18% (3/17) radiologically. The vestibular aqueduct was most frequently dehiscent histologically (n = 41) and radiologically (n = 3). Posterior semicircular canal and facial nerve were infrequently dehiscent. Only 2 out of 41 histological cases of vestibular aqueduct dehiscence had hydrops or a clinical history of Ménière’s disease. Conclusion: JB abnormalities are common. They are present in 8% to 9% of individuals and are acquired by age 40 years. In 1/3 of cases, high riding JB erodes the inner ear, most frequently involving the vestibular aqueduct. Contrary to expectation, dehiscence of the vestibular aqueduct is infrequently associated with endolymphatic hydrops clinically or histologically.

Conductive Hearing Loss After Removal of Acoustic Neuroma

To report 4 patients who have developed a conductive and/or mixed hearing loss due to dehiscence of the inner ear after retrosigmoid approach for removal of acoustic neuroma. Four patients who presented with conductive and/or mixed hearing loss after retrosigmoid approach for removal of acoustic neuroma. Evidence of inner ear dehiscence on postoperative computed tomographic scan of the temporal bones. The occurrence of conductive hearing loss after the surgical removal of an acoustic neuroma has not previously been documented. Computed tomographic scan of the temporal bones showing inner ear dehiscence may explain this finding. Formal documentation of such cases may allow techniques to be developed to reduce its occurrence or reconstruction of the defect at the time of primary surgery.