Petrous high jugular bulb: a histological study

Assessing the feasibility of the transmastoid infralabyrinthine approach without decompression of the jugular bulb to the extradural part of the petrous apex and petroclival junction prior to surgery

BACKGROUND AND OBJECTIVE

This study aims to define specific measurements on cranial high-resolution computed tomography (HRCT) images prior to surgery to prove the feasibility of the navigated transmastoid infralabyrinthine approach (TI-A) without rerouting of the facial nerve (FN) and decompression of the jugular bulb (JB) in accessing the extradural-intrapetrous part of petrous bone lesions located at the petrous apex and petroclival junction.

MATERIALS AND METHODS

Vertical and horizontal distances of the infralabyrinthine space were measured on cranial HRCT images prior to dissection. Subsequently, the area of access was measured on dissected human cadaveric specimens. Infralabyrinthine access to the extradural part of the petrous apex and petroclival junction was evaluated on dissected specimens by two independent raters. Finally, the vertical and horizontal distances were correlated with the area of access.

RESULTS

Fourteen human cadaveric specimens were dissected bilaterally. In 54% of cases, the two independent raters determined appropriate access to the petrous apex and petroclival junction. A highly significant positive correlation (r = 0.99) was observed between the areas of access and the vertical distances. Vertical distances above 5.2 mm were considered to permit suitable infralabyrinthine access to the extradural area of the petrous apex and petroclival junction.

CONCLUSIONS

Prior to surgery, vertical infralabyrinthine distances on HRCT images above 5.2 mm provide suitable infralabyrinthine access to lesions located extradurally at the petrous apex and petroclival junction via the TI-A without rerouting of the FN and without decompression of the JB.

High jugular bulb in patients with non-thrombotic internal jugular venous and transverse sinus stenosis: Clues to pathogenesis

AIMS

Conventional theories for jugular bulb (JB) formation are insufficient to explain the high proportion of high JB in adult patients. We aimed to study features of high JB in patients with non-thrombotic internal jugular venous stenosis (IJVS) and/or transverse sinus stenosis (TSS) to explore the pathogenesis of high JB formation.

METHODS

We retrospectively enrolled consecutive patients with the diagnosis of non-thrombotic IJVS and/or TSS. The relationship between IJVS and/or TSS and high JB was explored. Logistic regression analysis was performed to identify potential independent risk factors for high JB.

RESULTS

A total of 228 patients were included in the final analyses. The proportions of IJVS, dominant-side IJVS, and non-TSS in dominant-side high JB subgroup were higher than those in nondominant-side high JB subgroup (83.3% vs. 62.5%, p < 0.001; 72.2% vs. 18.3%, p < 0.001; 43.5% vs. 29.2%, p = 0.02). Heights of JBs on dominant sides in IJVS subgroup and non-TSS subgroup were higher than those in non-IJVS subgroup and TSS subgroup (12.93 ± 2.57 mm vs. 11.21 ± 2.76 mm, p < 0.001; 12.66 ± 2.71 mm vs. 11.34 ± 2.73 mm, p = 0.003). Multivariate logistic regression indicated an independent association between dominant-side IJVS and dominant-side high JB (odds ratio, 29.40; 95% confidence interval, 11.04-78.30; p < 0.001).

CONCLUSION

IJVS and asymmetric transverse sinus were independently and positively associated with high JB, especially dominant-side IJVS with dominant-side high JB, indicating a potential hemodynamic relationship between IJVS and high JB formation. Conversely, TTS might impede high JB formation.

The association between high jugular bulb and mastoid pneumatization in adults

Purpose

The purpose of this study was to analyze the relationship between the degree of high jugular bulb (HJB) and mastoid pneumatization using high-resolution computed tomography (HRCT).

Methods

Between April 2019 and June 2022, HRCT of the temporal bone was retrospectively analyzed in 1,025 patients. By excluding the other coexistent pathologies, 113 patients with HJBs were recruited for the study. The degree of the HJBs were defined as follows: Grade I, JB situated between inferior annulus of tympanic membrane and cochlear basal turn (CBT). Grade II, JB situated between CBT and lateral semicircular canal (LSC). Grade III, JB situated above LSC. The volume of mastoid pneumatization was based on HRCT images using a 3D reconstruction.

Results

There were 32 male and 81 female subjects (mean age, 41.2 ± 14.0 years; age range, 18-80 years). The male group included 16 Grade I, 28 Grade II and 6 Group III HJB subjects. The female group included 38 Grade I, 62 Grade II and 31 Group III HJB cases. In the different groups of HJB, the mastoid cell volume differences were also not statistically significant (p = 0.165). In the classification, Grade II was most common (90/181, 49.7%).

Conclusion

This study found no correlation between mastoid air cell volume and HJB, suggesting that HJB may not affect the mastoid air cell development and disease occurrence. These data must be considered exploratory, requiring more extensive cross-sectional studies.

Influence of pneumatization on morphology of temporal bone-related vasculatures and their morphometric relationship with ear regions: a computed tomography study

Anatomical variations in the location and position of temporal bone-related vasculature are routinely encountered in clinical practice, contributing to clinical syndromes and complexities in ear-related and neurological surgeries. Pneumatization of the temporal bone (TB) is one of several factors that have been hypothesized to influence the variabilities and variations of these vessels. This study aimed to investigate the association between the degree of pneumatization and the morphologies of some TB-related vessels, as well as their morphometrical relationship with ear regions. Observational retrospective chart review of 496 TBs computed tomographic scans were examined. Different degrees of pneumatization were observed, with hyper-pneumatization being the most common and hypo-pneumatization being the least. Various anatomical variants of the sigmoid sinus (SS), jugular bulb (JB), and internal carotid artery (ICA) were observed. Distances of SS and JB to ear regions were observed to have significant differences (p < 0.05) in laterality. These distances increased relative to increased air cells, showing a significant association (p < 0.05). A significant association (p < 0.001) was also observed between the degree of pneumatization and variants of JB and ICA. High JB, JB dehiscence, and ICA dehiscence were significantly associated with increased pneumatization, while flat JB was significantly associated with decreasing pneumatization. However, no significant association (p = 0.070, p = 0.645) was observed between the degree of pneumatization and morphologies of SS. This study concludes that the degree of pneumatization influences only the jugular bulb variants and ICA dehiscence, as well as the distances of SS and JB to ear regions.

CT evaluation of unilateral pulsatile tinnitus with jugular bulb wall dehiscence

OBJECTIVES

To investigate the imaging features of unilateral pulsatile tinnitus (PT) with jugular bulb wall dehiscence (JBWD).

METHODS

Computerized tomography angiography images of unilateral PT patients were reviewed between 2019 and 2021. Thirty-one symptomatic JBWD patients without sigmoid sinus wall dehiscence (SSWD) were included. Thirty-eight patients with SSWD were used as the control group. The prevalence of JBWD was calculated. The area and height of the jugular bulb, the extent of dehiscence, the presence of jugular bulb diverticulum, posterior condylar emissary vein (PCEV), oblique occipital sinus (OOS), venous outflow laterality (VOL), the degree of transverse sinus stenosis (TSS), and the pituitary height to sella turcica ratio were compared between the two groups.

RESULTS

The prevalence of JBWD was 12.1%, and JBWD was established as a causative diagnosis in 5.0% of unilateral PT patients. There were no statistical differences in the gender, symptomatic side, or VOL between the two groups. The area of the jugular bulb was larger and the height was higher (p_area < 0.001, p_height = 0.005). The prevalence of jugular bulb diverticulum was higher in the JBWD group (p = 0.002). The degree of symptomatic TSS was less severe (p < 0.001), and the prevalence of bilateral TSS was lower in the JBWD group (p < 0.001). The pituitary height to sella turcica ratio was greater (p = 0.004), the prevalence of PCEV (p = 0.014) was lower, and OOS (p = 0.015) was greater in the JBWD group.

CONCLUSIONS

The correlating factors of PT with JBWD and PT with SSWD are significantly different. These findings can further facilitate early and efficient PT treatment.

KEY POINTS

• The incidence of jugular bulb dehiscence (JBWD) accounted for approximately 12.1% in pulsatile tinnitus (PT) patients, and JBWD was established as a causative diagnosis in 5.0% of PT patients. • PT required large blood flows and abnormal flow patterns, whether in JBWD or sigmoid sinus wall dehiscence groups. • JBWD causing PT has some unique characteristic findings on CT.

Radiological requirements for surgical planning in cochlear implant candidates

Objective:

This study is concerned with clarification of radiological findings that should be addressed and reported in patients listed for cochlear implant (CI) operation. These findings may force a surgeon to consider modifications of the surgical approach by a CI surgeon.

Materials and Methods:

The study was performed from January 2015 to January 2016. It included 50 patients with severe-to-profound sensorineural hearing loss who fulfilled the criteria for CI. Patients underwent CI surgery in the Department of Otolaryngology. All patients underwent preoperative computed tomography (CT) and magnetic resonance imaging (MRI) assessment in the Department of Diagnostic Radiology. Combined examination of the CT and MRI by the radiologist and the surgeon was advocated.

Results:

Many anatomical variants were observed regarding the pattern of mastoid pneumatization, position of middle cranial fossa dura, sigmoid sinus position jugular bulb position, and the size and position of the mastoid segment of facial nerve canal. Labyrinthitis ossificans was seen in 3 patients (6%), otospongiosis in 1 patient (2%), and dilated vestibular aqueduct and endolymphatic sac in 9 patients (18%).

Conclusion:

Cochlear implantation is a major treatment modality in patients with severe-to-profound sensorineural hearing loss. Radiological evaluation is integral in surgery planning.

Prevalence of High Jugular Bulb across Different Stages of Adulthood in A Chinese Population

Pulsatile tinnitus, ear fullness, vertigo, hearing disorders, and vestibular dysfunction have been found to be related to high jugular bulb. Anatomical variation in this region also affects surgical planning and approaches. Therefore, knowledge on the detailed anatomy of the high jugular bulb is critical for middle ear and lateral skull base surgery. Prevalence of high jugular bulb is uncertain as data are usually derived from temporal bone specimens and patient reports from hospitals. Therefore, a community-based epidemiological study is necessary to understand the significance of high jugular bulb anatomy. Here, we report a cross-sectional study to characterize the prevalence of high jugular bulb and jugular bulb size using a 3.0 T magnetic resonance imaging. Furthermore, we studied the relationship between the prevalence of high jugular bulb and age-related changes. We enrolled 4539 permanent residents (9078 ears) from two communities in the Shanghai region who underwent magnetic resonance imaging between 2007 and 2011. We divided participants into four subgroups according to age: 35-44 (early middle age), 45-54 (middle age), 55-64 (late middle age), and 65-75 (late adulthood) years. We found that the overall prevalence of high jugular bulb was 14.5% in a Chinese population. There was a higher prevalence of high jugular bulb on the right side and especially in women (both p < 0.001). The occurrence of high jugular bulb was higher in the early middle age group and gradually decreased with age, but was still present in the late adulthood group (p = 0.039). These findings provide useful information on the prevalence of high jugular bulb in a Chinese population and the distribution in age groups, suggesting that high jugular bulb should be considered, even in those without ear disorders. This work serves as a foundation for further research on the relationship between jugular bulb changes and disease symptoms.

The Measurement of Various Anatomical Structures and Assessment of Morphometric Development of Fetal Skull Base

BACKGROUND

As the skull base has a complex anatomy, we underline the importance of anomalies for side asymmetry. It is useful to investigate relationship between anatomical structures for the surgical procedure orientations. Dural adherence, enlarged superior petrosal sinus, influence of neural crest cells, and cranial base ossification are among the factors in morphometric growth on skull base.

MATERIAL AND METHODS

Twenty-five fetuses of an estimated gestational age ranging from 17 to 34 weeks were studied in the Anatomy Laboratory of Mersin University Medical Faculty. Craniotomy was made to each fetus and brain hemispheres were dissected. We put plates, passing from the external points of lateral and anterior-posterior borders of fetus heads that are perpendicular to each other. An analytical calculation was formulated for the angle of foraminae to the root of zygoma by using different formulations depending on their posterior or anterior location to the root of zygoma. Statistical method was based on correlation analysis, simple regression, independent 2 group t tests, SPSS20.0, and MedCalc 11.5 (MedicReS, New York, NY).

RESULTS

Neither side dominance for the jugular foramen, nor the differences of foramen rotundum, spinosum, and ovale to anterior skull wall, root of zygoma, and to midline were found to be significant.

CONCLUSION

There is a debate on asymmetry of foramina of the skull base. No certain consensus about the initiation time and the causes of asymmetry in the past was documented. Studies are to be encouraged to further enlighten pre-postnatal factors affecting the fetal skull base morphometrism.

The Prevalence of Persistent Petrosquamosal Sinus and Other Temporal Bone Anatomical Variations on High-Resolution Temporal Bone Computed Tomography

BACKGROUND The aim of the study was to determine the prevalence of petrosquamosal sinus (PSS) and other temporal bone (TB) anatomical variations in various patients using high-resolution computed tomography (CT). MATERIAL AND METHODS We reviewed clinical and consecutively obtained CT data for 276 TBs of 138 patients. The incidence of TB anatomical variations was compared among patients with radiological markers of chronic otitis media (RCOM) and non-RCOM. RESULTS The PSS incidence in our sample was 6.9%, and it was significantly higher in TBs with RCOM (14.6%). Selected anatomical variations of RCOM TBs were observed: lateral sigmoid sinus (14.5%), prominent sigmoid sinus (23.6%), PSS (14.6%), and high jugular bulb (17.3%). Lateral sigmoid sinus and prominent sigmoid sinus (p<0.01), high jugular bulb (p<0.05), and PSS (p<0.01) were observed more often in RCOM than in non-RCOM TBs. CONCLUSIONS The TB vascular and anatomical variations, including PSS, a high jugular bulb, and a laterally and prominent placed sigmoid sinus, were more often observed in TBs with RCOM. Presurgical imaging and CT-based navigation techniques for TB surgery can offer remarkable value for understanding the altered anatomy of this complex structure and can localize rare anatomical variations.

The effect of jugular bulb-vestibular aqueduct dehiscence on hearing and balance

CONCLUSION

This study suggests that jugular bulb-vestibular aqueduct dehiscence (JBVAD) does not affect the hearing or balance functions of the inner ear.

OBJECTIVES

Since JBVAD may cause impairment of the inner ear and induce hearing loss, tinnitus, and vertigo, this study was to investigate the effect of JBVAD on hearing and balance.

METHOD

Patients undergoing temporal bone computed tomography (TBCT) scans from May 2013 to December 2013 at a tertiary referral hospital were reviewed. The topographic relationship between the jugular bulb (JB) and the vestibular aqueduct was assessed. The findings were classified as normal when there was always a bony structure between the two structures and as dehiscent when the bony coverage separating the two structures was absent. Clinical data were collected via electronic records and clinical follow-up.

RESULTS

A total of 1313 out of 8325 patients were diagnosed with a HJB. Forty-six patients showed JBVAD. The prevalence of dehiscence was 0.6% in patients undergoing temporal bone CT scans and 3.5% in patients with HJB. Of the 46 patients with JBVAD, 23 (50%) had sensorineural hearing loss, three (6.5%) had tinnitus, and two (4.3%) had vertigo. The correlation between JBVAD and these clinical symptoms did not achieve statistical significance.

Treatment of venous pulsatile tinnitus in younger women

BACKGROUND

We present 7 cases of pulsatile tinnitus (PT) of venous origin in younger women seen over a period of 24 years and treated by Internal Jugular Bulb ligation.

METHODS

All patients had a pulsatile bruit in one side of the neck that disappeared when gentle pressure over the internal jugular vein (IJV) caused it to collapse as seen in a duplex scan. Their computed tomography showed a dominant venous system with a high jugular bulb on the side of the bruit.

RESULTS

The IJV was ligated under local anesthesia. Five patients in whom the ligation was done above the facial vein were cured. Two patients in whom the ligation was done below the facial vein experienced a decrease but not disappearance of the PT.

CONCLUSIONS

Once other possible causes for PT have been discarded, ligation of the IJV above the facial vein cures this condition.

High jugular bulb in a cohort of patients with definite Ménière's disease

OBJECTIVE

To determine the incidence of high jugular bulb in a group of patients with definite Ménière's disease, and to investigate whether the position or size of the jugular bulb is significantly different in the affected ear than in the unaffected ear.

METHODS

Retrospective review of patient charts, audiograms, and computed tomography scans to determine the position and size of the jugular bulb in the affected and contralateral ears, as well as other abnormalities.

RESULTS

High jugular bulb was found in 57.1 per cent of affected ears. Encroachment of the cochlear and vestibular aqueducts was apparent in 39.3 per cent and 35.7 per cent, respectively, of affected ears. Diverticulum and dehiscence were observed in 28.6 per cent of affected ears. High jugular bulb was significantly associated with encroachment of the cochlear aqueduct (p = 0.003).

CONCLUSION

The mediolateral and anteroposterior position of the jugular bulb determines encroachment of the surrounding structures. An abnormal position is postulated to contribute to the development of Ménière's disease.

Audiological signs in pediatric cases with dehiscence of the bony labyrinth caused by a high jugular bulb

Clinical findings were assessed in three pediatric cases of dehiscence of the bony labyrinth caused by a high jugular bulb (HJB). Two children had two dehiscent lesions, which included posterior semicircular canal dehiscence (PSCD) and vestibular aqueduct dehiscence (VAD). One child had VAD alone. Two subjects with PSCD, but not with VAD alone, had mixed hearing loss and showed wave motion of the baseline on tympanometry and acoustic reflex testing, and a reduced response on otoacoustic emission. These findings may reflect jugular venous pulsations transmitted through the PSC and represent characteristics of cases with PSCD caused by HJB.

Temporal bone high-resolution computed tomography in non-syndromic unilateral hearing loss in children

OBJECTIVE

The aim of this study was to disclose possible inner ear abnormalities/pathologies by means of high-resolution computed tomography (HRCT) of the temporal bone (TBHRCT) in children with unilateral hearing loss (UHL).

METHODS

Retrospective review of audiological evaluation and TBHRCT in 22 children with UHL.

RESULTS

Two thirds of the children showed profound hearing loss. Review of HRCT scans identified inner ear malformations/pathologies in 9 (41%) cases and a high jugular bulb (HJB), always dehiscent with the vestibular aqueduct, in another 5 (22%). Inner ear malformations included enlarged vestibular aqueduct, common cavity and cochleovestibular hypoplasia, while labyrinthine ossification was the detected pathology. In 1 child, the common cavity of the right ear was associated with congenital melanocytic naevus of the left eyelid and lipomeningocele. To the best of our knowledge, this condition has never been described.

CONCLUSIONS

The aetiology of UHL may be revealed in more than half of patients by means of TBHRCT. Besides common inner ear abnormalities, TBHRCT should be evaluated carefully to rule out HJB, dehiscences, diverticulum or erosion of inner ear structures.

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.

An anatomical and radiological study of the high jugular bulb on high-resolution CT scans and alcohol-fixed skulls of adults

Although many reports mention a "high jugular bulb" (HJB), it is often not clearly defined. We examined the relationship between the jugular bulb (JB) and the internal auditory canal (IAC) in 200 temporal bones on high resolution CT scans and alcohol-fixed skull bases of adults. The average distance (+/-standard deviation) between the IAC and the JB was 7.5+/-2.3mm (range, 1-16 mm). The JB was higher on the right side than its companion in 53.3% of patients (left side only in 22%; no side dominance in 23.7% of bases). When the JB reached or exceeded the floor of the IAC (16.5%), it was defined as a HJB; 61% of HJB were found in females. Bilateral HJB was found in 0.5% of patients. The HJB was not associated with a contralateral flat JB. Preoperative multiplanar high resolution CT reconstructions make the most detailed assessment of structural topography.

Anatomical delineation of a safety zone for drilling the internal acoustic meatus during surgery for vestibular schwanomma by retrosigmoid suboccipital approach

Drilling the internal acoustic meatus (IAM) is an important step during surgical removal of vestibular schwanommas. During this maneuver, the proximity of the jugular bulb and the saccus endolymphaticus to the IAM makes these structures prone to injury. There have been studies in the past on the relationship between a high jugular bulb (HJB) and the IAM, but there is no description of a safety area available for drilling the meatus. In the present study, measurements were made between the IAM and the nearest points on the top of the jugular bulb, the saccus endolymphaticus and the petrous ridge. The incidence of a HJB was also calculated. It was found that about 5 mm of bone could be safely drilled away from the posterior lip of the IAM without damaging either the jugular bulb or the saccus endolymphaticus in most of the cases. The incidence of HJB was found to be 38.6% with 18.1% having a very high bulb. Thus, a significant proportion of patients are likely to have a HJB. Since there are significant individual variations, a preoperative radiological study for delineation of important bony landmarks is necessary in all patients undergoing surgery for vestibular schwanommas.

Surgical anatomy of the jugular foramen

The jugular foramen (JF) is a canal that makes communication between the posterior cranial fossa and the upper neck for one third of the cranial nerves and for the main venous channel of the brain. From a lateral view, the JF is protected by multiple layers of muscles and by the outer surface of the petrous bone. Surgical exposure of the JF is usually justified by the removal of benign tumors that grow in this region. In the first part of the present study we describe the surgical anatomy of the JF Then, we detail the relevant points of a stepwise surgical progression of three lateral skull base approaches with a gradual level of exposure and invasiveness. The infralabyrinthine transsigmoid transjugular-high cervical approach is a conservative procedure that associates a retrolabyrinthine approach to a lateral dissection of the upper neck, exposing the sinojugular axis without mobilization of the facial nerve. In the second step, the external auditory canal is transsected and the intrapetrous facial nerve is mobilized, giving more exposure of the carotid canal and middle ear cavity. In the third step, a total petrosectomy is achieved with sacrifice of the cochlea, giving access to the petrous apex and to the whole course of the intrapetrous carotid artery. Using the same dissection of the soft tissues from a lateral trajectory, these three approaches bring solutions to the radical removal of distinct tumor extensions. While the first step preserves the facial nerve and intrapetrous neurootologic structures, the third one offers a wide but more aggressive exposure of the JF and related structures.

High jugular bulb in the translabyrinthine approach to the cerebellopontine angle: anatomical considerations and surgical management

BACKGROUND

Evidence of a high jugular bulb position (HJBP) during the translabyrinthine approach may compromise the surgical removal of cerebellopontine angle (CPA) tumours. We report a simple surgical procedure to safely manage this frequent normal variation and comment on various alternative options.

METHODS

The translabyrinthine approach included a complete skeletonization of the sigmoid sinus and of the presigmoid dura. A thin eggshell bone was left at the jugular bulb surface. The dome of the jugular bulb was gently dissected from the jugular fossa and gradually retracted downward in a tailored way, allowing the surgeon to drill below the internal auditory meatus. A small piece of bone was wedged over the jugular dome in order to maintain its lowered position.

RESULTS

Among 178 consecutive translabyrinthine approaches performed for the removal of large CPA tumors, the use of this procedure was required in 44 cases of HJBP. Excepting minimal venous bleeding easily controlled in several cases, we never observed any complication from this procedure nor failure to expose the inferior compartment of the CPA.

CONCLUSIONS

The HJBP can be systematically diagnosed with the preoperative CT-scan using bone window imaging. Our results demonstrate that the described procedure is safe and effective to widen the operative corridor that is required for the exposure of the inferior compartment of the CPA in this anatomical situation.

Operative Management of a Posterior Semicircular Canal Dehiscence

OBJECTIVE

The objective of this study was to describe the operative management of posterior canal dehiscence.

METHODS

A transmastoid approach to and plugging of the posterior canal was performed for posterior semicircular canal dehiscence (PSCD).

RESULTS

Postoperatively, the patient exhibited improvement in conductive hearing loss and vestibular symptoms.

CONCLUSIONS

PSCD can cause symptoms identical to that of superior semicircular canal dehiscence. Successful PSCD plugging can be performed without visualization of the actual area of dehiscence.

Relationship of vestibular aqueduct and inner ear pressure in Ménière's disease and the normal population

OBJECTIVE

Etiopathogenesis of Ménière's disease has not been resolved. The principal histopathologic finding in this disease is endolymphatic hydrops. The majority of radiologic and histopathologic studies demonstrated a narrow vestibular aqueduct in Ménière's disease. There is no study in the literature investigating the relationship between inner ear pressure and vestibular aqueduct dimensions. Static acoustic compliance is a noninvasive procedure that is thought to measure perilymphatic pressure at the footplate. An increase in mechanical fluid pressure in the inner ear is transmitted to the footplate of the stapes. This causes a reduction in the compliance at the drum. The aim of this study is to investigate the relationship between vestibular aqueduct dimensions and static acoustic compliance in Ménière's disease and the normal population.

STUDY DESIGN

Prospective study.

METHODS

Forty patients with Ménière's disease and 40 healthy individuals with no otolaryngologic disorders were the subjects of this study. Each group was further divided into two according to static compliance value (normal and low static compliance). In these four groups dimensions of vestibular aqueduct were determined radiologically by high-resolution computerized tomography and correlated with normal and low static acoustic compliance values (normal and high perilymphatic pressure).

RESULTS

The results demonstrated that vestibular aqueduct is narrower in patients with Ménière's disease than the normal population. However, there is no relationship between vestibular aqueduct dimensions and inner ear pressure obtained by static acoustic compliance measurements.