Vascular variations of the inner ear

Hypertension Associated With Hearing Loss and Tinnitus Among Hypertensive Adults at a Tertiary Hospital in South Africa

Introduction

Hypertension is one of the leading causes of morbidity and mortality worldwide, and has been associated with target organ damage. Effects of hypertension on the auditory system are varied and requires further investigation. This study aimed to investigate the association between hypertension and auditory deficits (hearing loss and tinnitus).

Methods

This study employed a cross-sectional study including 106 (54.7% female) hypertensive adults aged 18–55 years, and 92 (52.2% female) non-hypertensive sex- and age-matched adults residing in South Africa. A data extraction sheet was used to obtain hypertension information from participants' medical files, and to subjectively obtain tinnitus status and characteristics among participants. Participants' hearing sensitivity—including extended high frequencies (EHF)—were measured using a diagnostic audiometer. The χ2 test determined the difference in auditory deficit prevalence between the study groups. Logistic regression was used to identify predictor variables associated with auditory deficits in the hypertensive group.

Results

A hearing loss prevalence of 37.4% among hypertensive adults compared to 14.1% among the non-hypertensive group (P = 0.000, χ2 = 14.00) was found. The EHF pure-tone average among the hypertensive group was 44.1 ± 19.2 dB HL, and 20.0 ± 18.3 dB HL among the control group. Bilateral mild sensorineural hearing loss was the most common type of hearing loss among hypertensive adults. A higher prevalence of tinnitus (41.5%) was found in the hypertensive group compared to the control group (22.8%) (P = 0.008, χ2 = 7.09). In this study, 30.3% of hypertensive adults had tinnitus without hearing loss compared to 17.7% non-hypertensive adults. Factors associated with hearing loss included being between 50 and 55 years [adjusted Odds Ratio (AOR) = 3.35; 95% Confidence Interval (CI): 1.32–8.50; P = 0.011], having grade 2 hypertension (AOR = 4.18; 95% CI: 1.02–17.10; P = 0.048), and being on antihypertensive medication (AOR = 3.18; 95% CI: 1.02–9.87; P = 0.045). Tinnitus was associated with grade 3 hypertension (AOR = 3.90; 95% CI: 1.12–12.64; P = 0.033).

Conclusions

Our study showed that hypertensive adults had a higher proportion of hearing loss and tinnitus compared to non-hypertensive adults. Findings suggest an association between hypertension and auditory deficits, demonstrating a need for integration of hearing healthcare services for hypertension management.

Association of Metabolic Syndrome with Sensorineural Hearing Loss

The prevalence of sensorineural hearing loss has increased along with increases in life expectancy and exposure to noisy environments. Metabolic syndrome (MetS) is a cluster of co-occurring conditions that increase the risk of heart disease, stroke and type 2 diabetes, along with other conditions that affect the blood vessels. Components of MetS include insulin resistance, body weight, lipid concentration, blood pressure, and blood glucose concentration, as well as other features of insulin resistance such as microalbuminuria. MetS has become a major public health problem affecting 20–30% of the global population. This study utilized health examination to investigate whether metabolic syndrome was related to hearing loss. Methods: A total of 94,223 people who underwent health check-ups, including hearing tests, from January 2010 to December 2020 were evaluated. Subjects were divided into two groups, with and without metabolic syndrome. In addition, Scopus, Embase, PubMed, and Cochrane libraries were systematically searched, using keywords such as “hearing loss” and “metabolic syndrome”, for studies that evaluated the relationship between the two. Results: Of the 94,223 subjects, 11,414 (12.1%) had metabolic syndrome and 82,809 did not. The mean ages of subjects in the two groups were 46.1 and 43.9 years, respectively. A comparison of hearing thresholds by age in subjects with and without metabolic syndrome showed that the average pure tone hearing thresholds were significantly higher in subjects with metabolic syndrome than in subjects without it in all age groups. (p < 0.001) Rates of hearing loss in subjects with 0, 1, 2, 3, 4, and 5 of the components of metabolic syndrome were 7.9%, 12.1%, 13.8%, 13.8%, 15.5% and 16.3%, respectively, indicating a significant association between the number of components of metabolic syndrome and the rate of hearing loss (p < 0.0001). The odds ratio of hearing loss was significantly higher in subjects with four components of metabolic syndrome: waist circumference, blood pressure, and triglyceride and fasting blood sugar concentrations (p < 0.0001). Conclusions: The number of components of the metabolic syndrome is positively correlated with the rate of sensorineural hearing loss.

A study on the association of cervical spondylosis severity, as indicated by cervical motions, with hearing impairment

Study aim: The present study investigates the possible relation between the limitation of cervical motion in a patient with cervical spondylosis and hearing impairment.

Material and methods: Cross-sectional research was performed based on 60 participants suffering from cervical spondylosis (CS) selected from an orthopaedic and physiotherapy department. The data collection techniques included questionnaire, electronic tools, measurements with a mechanical device including measuring the cervical range of motion (ROM) by goniometer, and physical examination including pure tone audiometry (PTA) and tympanogram.

Results: Right rotation was the most common limitation, which affected 43 patients, followed by left rotation limitation, which was recorded in 40 patients. The extension, left lateral flexion, flexion, and right lateral flexion limitation showed less effect.

Conclusions: Left rotation limitation was found to be an independent predictor of hearing impairment especially in men. Age was also a risk factor for sensory neural hearing loss (SNHL). These findings are important in the facilitation of investigating SNHL in cervical spondylosis patients.

Hearing loss, tinnitus, and hypertension: analysis of the baseline data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

OBJECTIVES

To investigate the association among hypertension, tinnitus, and sensorineural hearing loss and evaluate the influence of other covariates on this association.

METHODS

Baseline data (2008-2010) from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) were analyzed. Altogether, 900 participants were evaluated. The baseline assessment consisted of a 7-hour examination to obtain clinical and laboratory variables. Hearing was measured using pure-tone audiometry.

RESULTS

Overall, 33.3% of the participants had hypertension. Participants with hypertension were more likely to be older, male, and diabetic compared to those without hypertension. The prevalence of tinnitus was higher among hypertensive participants and the odds ratio for tinnitus was higher in participants with hypertension than in those without hypertension. However, the difference was not significant after adjusting for age. Audiometric results at 250-8,000 Hz were worse in participants with hypertension than in those without hypertension in the crude analysis; however, the differences were not significant after adjustment for age, sex, diagnosis of diabetes, and exposure to noise. No significant difference was observed in hearing thresholds among participants having hypertension for <6 years, those having hypertension for ≥6 years, and individuals without hypertension.

CONCLUSION

Hearing thresholds were worse in participants with hypertension. However, after adjusting for age, sex, diagnosis of diabetes, and exposure to noise, no significant differences were observed between participants with and without hypertension. A higher prevalence of tinnitus was observed in participants with hypertension compared to those without hypertension, but without significance after adjusting for age.

Metabolic syndrome is associated with hearing disturbance

BACKGROUND

Although metabolic syndrome (MetS) has been associated with various diseases, few studies to date have addressed the association between MetS and hearing loss.

AIMS/OBJECTIVES

This cross-sectional review of health examination center data sought to determine the association between MetS and hearing disturbance.

MATERIAL AND METHODS

This study involved 28,866 subjects. Height, weight, waist circumference, and blood pressure were measured, and basic blood tests and pure-tone audiometry (PTA) were performed. Other factors analyzed included body mass index, hypertension, diabetes mellitus, and hyperlipidemia.

RESULTS

Age and gender did not differ between subjects with and without MetS. PTA was slightly higher in subjects with than without MetS, but the difference was not statistically significant (p = .47). The incidence of hearing loss was no higher in subjects who met three of the five diagnostic criteria of MetS than in those who met 0-2 criteria, but was significantly higher in subjects who met four (p = .04) and five (p < .01) criteria.

CONCLUSIONS AND SIGNIFICANCE

MetS may be associated with hearing loss, especially in subjects who meet four or five of the diagnostic criteria for MetS.

Effects of diabetes mellitus and systemic arterial hypertension on elderly patients’ hearing

Introduction

Chronic diseases can act as an accelerating factor in the auditory system degeneration. Studies on the association between presbycusis and diabetes mellitus and systemic arterial hypertension have shown controversial conclusions.

Objective

To compare the initial audiometry (A1) with a subsequent audiometry (A2) performed after a 3 to 4-year interval in a population of elderly patients with diabetes mellitus and/or systemic arterial hypertension, to verify whether hearing loss in these groups is more accelerated when compared to controls without these clinical conditions.

Methods

100 elderly individuals participated in this study. For the auditory threshold assessment, a previous complete audiological evaluation (A1) and a new audiological evaluation (A2) performed 3–4 years after the first one was utilized. The participants were divided into four groups: 20 individuals in the diabetes mellitus group, 20 individuals in the systemic arterial hypertension group, 20 individuals in the diabetes mellitus/systemic arterial hypertension group and 40 individuals in the control group, matching them with each study group, according to age and gender. ANOVA and Kruskal–Wallis statistical tests were used, with a significance level set at 0.05.

Results

When comparing the mean annual increase in the auditory thresholds of the A1 with the A2 assessment, considering each study group and its respective control, it can be observed that there was no statistically significant difference for any of the frequencies for the diabetes mellitus group; for the systemic arterial hypertension group, significant differences were observed after 4 kHz. For the diabetes mellitus and systemic arterial hypertension group, significant differences were observed at the frequencies of 500, 2 kHz, 3 kHz and 8 kHz.

Conclusion

It was observed that the systemic arterial hypertension group showed the greatest decrease in auditory thresholds in the studied segment when compared to the other groups, suggesting that among the three studied conditions, hypertension seems to have the greatest influence on hearing.

Biochemical alteration in children with idiopathic nephrotic syndrome associated with an increased risk of sensorineural hearing loss; additional insights in cochlear renal relationship

OBJECTIVES

Children with Idiopathic Nephrotic Syndrome (INS) are at risk of hearing loss due to the adverse impact of medications and related immunological and genetic factors on both cochlea and kidney. So this work was planned to evaluate hearing status in children with INS and to clarify the possible associated risk factors by interpreting the clinical and laboratory profiles of those children.

METHODS

Ninety children with INS aged 5-14 years [30 patients with steroid-sensitive nephrotic syndrome (SSNS), 30 patients with steroid dependent/frequently relapsing nephrotic syndrome (SDNS/FRNS), and 30 patients with steroid-resistant nephrotic syndrome (SRNS)], and 90 age and sex matched normal controls were enrolled into this study. Laboratory measurements of serum calcium, creatinine, cholesterol, blood urea and other relevant investigations were done. Pure tone audiometry was done with the sensory-neural hearing loss (SNHL) diagnosed when the level bone conduction was >20 dB and the difference in air to the bone gap was <15 dB.

RESULTS

40% children with INS had SNHL, mostly of mild degree HL and primarily occurred at the lower frequencies. A highly significant statistical difference between controls and various types of nephrotic syndrome regarding pure tone audiometry measurements at frequencies 250, 500, 1000 Hz, whereas insignificant difference interpreting pure tone audiometry measurements in 2000, 4000 and 8000 Hz.

CONCLUSIONS

Children with different phenotypes of nephrotic syndrome are at risk of sensorineural hearing impairment. The hazards associated with this impairment were higher blood pressure, hypercholesterolemia, hypoalbuminemia, and hypocalcemia.

Interaction between diabetes mellitus and hypertension on hearing of elderly

INTRODUCTION

Chronic diseases and metabolic changes may act as accelerating factor in the degeneration of the auditory system due to age. However, studies involving an association between hearing loss and diabetes mellitus (DM) and hypertension (HA) in the elderly have shown controversial conclusions. Thus, further studies on this topic are needed in order to elucidate the effect of these chronic diseases on the auditory system.

AIM

To compare the hearing thresholds of elderly patients with DM, HA and DM + HA with a control group (CG).

METHODS

Retrospective study was conducted through survey charts of 80 elderly people with full hearing assessment, between 2008 and 2012. Subjects were divided into four groups: DM, HA, DM + HA and without chronic diseases known (CG). The ANOVA, Tukey and Mauchly tests, with a significance level of 0.05, were used.

RESULTS

There was no statistically significant difference between the ears, which are grouped. Comparisons between the means of hearing thresholds of CG and DM or HA showed no statistically significant differences. However, a statistically significant difference in the comparison between these three groups and DM + HA group for several of the frequencies evaluated was observed.

CONCLUSION

It was found that older adults with DM and hypertension associated showed greater hearing impairment in comparison with the other groups, suggesting a synergistic effect of the two chronic diseases on hearing.

The audiological profile of adults with and without hypertension

OBJECTIVE

To determine whether there is any influence of systemic arterial hypertension on the peripheral auditory system.

METHODS

This was a cross-sectional study that investigated 40 individuals between 30 and 50 years old, who were divided into groups with and without systemic arterial hypertension, using data from high-frequency audiometry, transient-evoked otoacoustic emissions and distortion-product otoacoustic emissions. The results were compared with those from groups of normal-hearing individuals, with and without systemic arterial hypertension, who underwent the pure-tone audiometry test. All individuals also underwent the following procedures: otoscopy, acoustic immittance measures, pure-tone audiometry at frequencies from 250 to 16000 Hz, transient-evoked otoacoustic emissions test and distortion-product otoacoustic emissions test.

RESULTS

No statistically significant difference was observed between the groups with and without systemic arterial hypertension in either conventional or high-frequency audiometry. Regarding transient-evoked otoacoustic emissions, there was a trend toward statistical significance whereby the systemic arterial hypertension group showed lower results. Regarding distortion-product otoacoustic emissions, the systemic arterial hypertension group showed significantly lower results at the following frequencies: 1501, 2002, and 3003 Hz. A discriminant analysis indicated that the distortion-product otoacoustic emissions variables best distinguished individuals with and without systemic arterial hypertension.

CONCLUSION

Data from this study suggest cochlear dysfunction in individuals with systemic arterial hypertension because their otoacoustic emission results were lower than those in the systemic arterial hypertension group.

Hearing loss as a function of aging and diabetes mellitus: a cross sectional study

Background

Although hearing loss may be caused by various factors, it is also a natural phenomenon associated with the aging process. This study was designed to assess the contributions of diabetes mellitus (DM) and hypertension, both chronic diseases associated with aging, as well as aging itself, to hearing loss in health screening examinees.

Methods

This study included 37,773 individuals who underwent health screening examinations from 2009 to 2012. The relationships between hearing threshold and subject age, hearing threshold at each frequency based on age group, the degree of hearing loss and the presence or absence of hypertension and DM were evaluated.

Results

The prevalence of hearing loss increased with age, being 1.6%, 1.8%, 4.6%, 14.0%, 30.8%, and 49.2% in subjects in their twenties, thirties, forties, fifties, sixties, and seventies, respectively (p<0.05). Hearing value per frequency showed aging-based changes, in the order of 6000, 4000, 2000, 1000 and 500 Hz, indicating greater hearing losses at high frequencies. The degree of hearing loss ranged from mild to severe. Aging and DM were correlated with the prevalence of hearing loss (p<0.05). There was no statistically significant association between hearing loss and hypertension after adjusting for age and DM.

Conclusions

The prevalence of hearing loss increases with age and the presence of DM. Hearing loss was greatest at high frequencies. In all age groups, mild hearing loss was the most common form of hearing loss.

Disabling vertigo and tinnitus caused by intrameatal compression of the anterior inferior cerebellar artery on the vestibulocochlear nerve: a case report, surgical considerations, and review of the literature

Microvascular compression of the vestibulocochlear nerve is known as a cause of tinnitus and vertigo in the literature, but our review of the literature shows that the compression is usually located in the cerebellopontine angle and not intrameatal.

We present a case of intrameatal compression of the anterior inferior cerebellar artery (AICA) on the vestibulocochlear nerve of a 40-year-old woman with symptoms of disabling vertigo and intermittent high-frequency tinnitus on the left side without any hearing loss for ∼ 4 years. Magnetic resonance imaging of the brain did not show any abnormality, but magnetic resonance angiography showed a left intrameatal AICA loop as a possible cause of the disabling symptoms. After the exclusion of other possible reasons for disabling vertigo, surgery was indicated. The intraoperative findings proved the radiologic findings. The large AICA loop was found extending into the internal auditory canal and compressing the vestibulocochlear nerve. The AICA loop was mobilized and separated from the vestibulocochlear nerve.

The patient's symptoms resolved immediately after surgery, and no symptoms were noted during 2 years of follow-up in our clinic. Her hearing was not affected by the surgery.

In addition to other common reasons, such as acoustic neuroma, disabling vertigo and tinnitus can occur from an intrameatal arterial loop compression of the vestibulocochlear nerve and may be treated successfully by drilling the internal acoustic meatus and separating the arterial conflict from the vestibulocochlear nerve.

Endolymphatic hydrops in Ménière's disease: cause, consequence, or epiphenomenon?

OBJECTIVE

To determine the relationship of endolymphatic hydrops to Ménière's disease.

DATA SOURCES

Comprehensive review of articles from 1938 through 2012 via Medline and Index Medicus.

STUDY SELECTION

Articles discussing Ménière's disease and/or endolymphatic hydrops that include temporal bone autopsy data.

DATA EXTRACTION

Fifty-three case reports and series were studied containing examination of 541 hydropic temporal bones and including 276 patients with Ménière's disease. These were divided into those meeting the 1995 American Academy of Otolaryngology-Head and Neck Surgery criteria for Ménière's disease and those that failed to meet these criteria.

CONCLUSION

An individual meeting the 1995 criteria for Ménière's disease has a near certain probability of having endolymphatic hydrops in at least 1 ear. Autopsy data do not support the view that the association of MD and EH is an epiphenomenon or that MD causes EH; this leaves us with the probability that EH causes MD. If it is causative, hydrops alone is insufficient to cause Ménière's disease, indicating that there must be one or more additional cofactors that cause asymptomatic hydrops to become symptomatic Ménière's disease. Vascular risk factors should be studied as possible cofactors.

Effects of hypertension on hearing

To determine the likely association between hypertension and hearing loss. 150 cases and 124 controls, both genders, aged 45-64, included in the research after sample estimation. Hypertension was verified through blood pressure readings and was classified as grade 1, grade 2 and grade 3 hypertension or no hypertension according to the blood pressure readings. Hearing was assessed by measuring pure tone threshold at various frequencies ranging between 250 and 8,000 Hz. There is a significant association between hypertension and increase in the hearing threshold. Hearing loss in the population under study suggests that hypertension is an accelerating factor of degeneration of the hearing apparatus due to aging. Association between Increased hearing threshold and hypertension in this research, can allow for an integrated work of cardiologists, nephrologists, otorhinolaryngologists, audiologists and other health professionals concerned with alterations caused by hypertension.

Vertigo and tinnitus caused by vascular compression of the vestibulocochlear nerve, not intracanalicular vestibular schwannoma: review and case presentation

Microvascular compression of the vestibulocochlear nerve is known to cause disabling tinnitus and vertigo. A review of the literature shows that the compression is usually located in the cerebellopontine angle, and that it is usually caused by an artery. The authors add the case of a 46-year-old man with venous compression of the vestibulocochlear nerve inside the internal auditory canal (IAC). The patient presented with a 2-year history of recurrent attacks of disabling vertigo and intermittent high-frequency tinnitus on the right side. Magnetic resonance images showed a small, contrast-enhancing lesion in the fundus of the right IAC, which was suspicious for vestibular schwannoma. During surgical exploration, a large venous loop was found extending into the IAC and compressing the vestibulocochlear nerve. The vessel was mobilized and rerouted out of the IAC. The presumed vestibular schwannoma at the cochlear fossa was left in situ. The patient's symptoms resolved immediately after surgery. Hearing was unchanged postoperatively. On follow-up, there has been no growth of the contrast-enhancing lesion in the IAC for 3 years so far.Disabling vertigo can also be caused by venous microvascular compression of the vestibulocochlear nerve inside the IAC and may be treated successfully by microvascular decompression. A sensitive, conservative approach to lesions in the fundus may be justified in the presence of an additional, more prominent pathology that causes compression of the vestibulocochlear nerve.

Immunocytochemical distribution of WARP (von Willebrand A domain-related protein) in the inner ear

The basic components of the epithelial, perineural, and perivascular basement membranes in the inner ear have been well-documented in several animal models and in the human inner ear. The von Willebrand A domain-related protein (WARP) is an extracellular matrix molecule with restricted expression in cartilage, and a subset of basement membranes in peripheral nerves, muscle, and central nervous system vasculature. It has been suggested that WARP has an important role in maintaining the blood-brain barrier. To date no studies on WARP distribution have been performed in the inner ear, which is equipped with an intricate vasculature network. In the present study, we determined the distribution of WARP by immunocytochemistry in the human inner ear using auditory and vestibular endorgans microdissected from human temporal bones obtained at autopsy. All subjects (n=5, aged 55-87years old) had documented normal auditory and vestibular function. We also determined the WARP immunolocalization in the mouse inner ear. WARP immunoreactivity localized to the vasculature throughout the stroma of the cristae ampullaris, the maculae utricle, and saccule in the human and mouse. In the human and mouse inner ear, WARP immunoreactivity delineated blood vessels located in the stria vascularis, spiral ligament, sub-basilar region, stromal tissue, and the spiral and vestibular ganglia. The distinct localization of WARP in the inner ear vasculature suggests an important role in maintaining its integrity. In addition, WARP allows delineation of microvessels in the inner ear allowing the study of vascular pathology in the development of otological diseases.

Hypertension as a factor associated with hearing loss

Aim

To identify likely association between blood hypertension and hearing loss. Design: A non-paired case-control study. Setting: Institutional work carried out at Universidade Norte do Paraná, in South Brazil.

Material and Method

154 cases and 154 controls, both genders, aged 45 to 64, included in the research after sample estimation. Methodology: Hypertension was verified through blood pressure readings and by a systematized questionnaire about hypertension and the use of medication for blood pressure. Hearing was assessed through tonal threshold audiometrics and audiologic anamneses. Non-conditional logistic regression was used in order to control likely confusion or modification of effect of other variables on interest associations.

Results

There is a significant association between blood hypertension and hearing loss. Hearing loss in the population under study suggests that hypertension is an accelerating factor of degeneration of the hearing apparatus due to aging.

Conclusions

The results in this research, through evidence of association between blood hypertension and hearing loss, can allow for an integrated work of cardiologists, nephrologists, otorhinolaryngologists, audiologists and other health professionals concerned with alterations caused by blood hypertension.

Queixa de vertigem e hipertensão arterial

OBJETIVO: investigar a presença de queixa de vertigem em pacientes de meia idade com hipertensão arterial. MÉTODOS: estudo do tipo prospectivo, transversal. Composto por 154 indivíduos de ambos os gêneros com idade de 45 a 64 anos. A hipertensão foi verificada por meio de medição da pressão arterial e de questionário sistematizado sobre hipertensão e uso de medicamentos para pressão arterial. A queixa de vertigem foi verificada por meio de anamnese audiológica. RESULTADOS: pode-se verificar que existe associação significante entre hipertensão arterial e queixa de vertigem. CONCLUSÃO: os resultados da presente pesquisa, por meio da constatação da associação entre hipertensão arterial e queixa de vertigem, servirão de base a profissionais da área de saúde que estão envolvidos com sintomas provenientes da hipertensão arterial.

Hipertensão como fator associado à perda auditiva

OBJETIVO: Identificar possível associação entre hipertensão arterial e perda auditiva. Foi realizado um estudo do tipo caso-controle não pareado, na Universidade Norte do Paraná, no Sul do Brasil. MATERIAL E MÉTODO: 154 casos e 154 controles, de ambos os sexos com idade variando de 45 a 64 anos foram incluídos na pesquisa após o cálculo da amostra. A hipertensão foi verificada por medição da pressão arterial e de questionário sistematizado sobre hipertensão e uso de medicamentos para pressão arterial. A audição foi avaliada por audiometria e anamnese audiológica. A técnica de regressão logística não-condicional foi utilizada com o objetivo de controlar a possível ação de confusão ou modificação de efeito exercida por outras variáveis sobre as associações de interesse. RESULTADOS : Pode-se verificar que existe associação significativa entre hipertensão arterial e presença de perda auditiva e que a perda auditiva observada nesta população sugere que a hipertensão arterial age como fator de aceleração da degeneração do aparelho auditivo proveniente da idade. CONCLUSÕES: Os resultados da presente pesquisa, através da constatação da associação entre hipertensão e perda auditiva, servirão de base a uma integração entre cardiologistas, nefrologistas, otorrinolaringologistas, fonoaudiólogos e outros profissionais da área de com alterações provenientes da hipertensão.

Vascular anomalies, sutures and small canals of the temporal bone on axial CT

PURPOSE

Subtle bony structures, small canals and fine sutures cause sometimes problems in the analysis of CTs of the temporal bone. The aim of this study was: to analyze the visibility of subtle structures and to estimate the incidence of vascular anomalies.

PATIENTS AND METHOD

We retrospectively analyzed axial scans of 223 high-resolution CTs of the temporal bone obtained as single slice or spiral CT with 1mm slice thickness. All CTs had clinical indications. Two experienced radiologists studied CTs regarding the visibility of the fine sutures, fissures and small canals and the occurrence of vascular anomalies.

RESULTS

The following structures were seen commonly: sphenosquamosal suture (76%), arcuate artery canal (93%), vestibular aqueduct (89%), mastoid emissary vein (82%), singular canal (56%). Not so commonly were observed: tympanosquamosal suture (31%), mastoid canaliculus (28%), lateral sigmoid sinus (28%), petrotympanic fissure (24%), tympanomastoid suture (10%). Seldom we identified: the inferior tympanic canaliculus (6%), high jugular bulb (6%), anterior sigmoid sinus (5%), dehiscent internal carotid artery canal (2%), persistent petrosquamosal sinus (1%), dehiscent jugular bulb (1%). Persistent stapedial artery, aberrant internal carotid artery, dehiscent jugular bulb, high jugular bulb with diverticulum, anterior and dehiscent sigmoid sinus were detected in below 1% of the analyzed temporal bones. The frequency of asymmetry of the jugular foramen, which varied between 3% and 42%, depended on different criterions of size.

CONCLUSION

A profound knowledge of normal anatomy and anomalies of the temporal bone avoids misinterpretation as pathological lesions and iatrogenic bleedings.

Disorders of cochlear blood flow

The cochlea is principally supplied from the inner ear artery (labyrinthine artery), which is usually a branch of the anterior inferior cerebellar artery. Cochlear blood flow is a function of cochlear perfusion pressure, which is calculated as the difference between mean arterial blood pressure and inner ear fluid pressure. Many otologic disorders such as noise-induced hearing loss, endolymphatic hydrops and presbycusis are suspected of being related to alterations in cochlear blood flow. However, the human cochlea is not easily accessible for investigation because this delicate sensory organ is hidden deep in the temporal bone. In patients with sensorineural hearing loss, magnetic resonance imaging, laser-Doppler flowmetry and ultrasonography have been used to investigate the status of cochlear blood flow. There have been many reports of hearing loss that were considered to be caused by blood flow disturbance in the cochlea. However, direct evidence of blood flow disturbance in the cochlea is still lacking in most of the cases.