Anatomy Of Eustachian Tube Research Articles

Anatomical Description and Literature Review of the Endoscopic Endonasal Transclival Transodontoid Approach Combined with Endoscopic Transoral Decompression to the Anterior Craniovertebral Junction: A New Strategy

To describe and evaluate the steps required to perform a combined endoscopic endonasal/transoral transclival transodontoid approach for anterior decompression of the craniovertebral junction. The endoscopic endonasal transclival transodontoid approach combined with endoscopic transoral decompression was performed on 4 cadaveric specimens. Evaluation of this combined technique; a review of the literature; and the nuances, advantages, and pitfalls are reported. Adequate wide anterior decompression was achieved in all specimens. This combined approach allowed the preservation of the anterior arch of C1 without injuring the eustachian tube anatomy and avoiding internal carotid artery manipulation. Mastery of both techniques allows for a safe and comfortable surgical corridor. The transoral and transnasal approaches should not be considered as either/or techniques, but rather as a complement to each other. However, as with all new or developing techniques, there is a steep learning curve, which requires ample training in the skull base laboratory.

Radiological Anatomy of Eustachian Tube and its Correlation with Graft Uptake in Type I Tympanoplasty

Introduction: Eustachian tube (ET) also known as pharyngotympanic tube connects nasopharynx with the middle ear. Evaluation of ET anatomy is aimed in patients with chronic otitis media. Materials and Methods: In a study of 53 patients, HRCT Temporal bone was done on 128 dual source simens somatom definition flash machine on 5mm cut section and tympanoplasty was carried out. Results: ET angle is one of the important factors for middle ear aeration. Outcome of tympanoplasty at 12th week was 88.7%. In the patients with vertical Eustachian Tube (i.e., more Eustachian Tube angle with the horizontal plane), better graft uptake in tympanoplasty was observed which was statistically significant. However, graft uptake did not correlate with the length of the Eustachian tube. Conclusion: It was concluded that on measuring ET length on HRCT, majority of the patients had bony length of 10-12 mm, cartilaginous length of 15-19 mm and total ET length of 28-32 mm. Majority of the patients had ET angle of 21-30 degrees with the hard palate.

A new “practical" plane for Eustachian tube measurements and its application in predicting middle ear dysfunction in patient with acquired cholesteatomas

SettingThe Eustachian tube plays a vital role in middle ear physiology. There has been evidence that Eustachian tube (ET) and angle are correlated with middle ear function. The measurements of these Eustachian tube features are now made possible with computed tomography and multiplanar reconstruction techniques. However, there has not been a standardised protocol devised to these measurements in limited window cone-beam CT scans of temporal bones.ObjectiveThe primary object of the present study is to establish and validate a new landmark in closer proximity to the middle ear that is consistently captured, thereby allowing ET angle and length to be measured from the majority of cone-beam CT scans. Secondarily, the ET anatomies of patients with middle ear dysfunction manifesting as acquired cholesteatoma are analysed with this new method of measurement.MethodsThis study undertook a step-by-step method to first validate the methods of ET measurement with Reid’s standard plane, then identifying an alternative landmark, thus a new plane visible on limited window cone-beam CT scans of temporal bones and lastly, validating the application of this new plane in the measurements of ET angle and length. This new method of measurement was coined the Ku-Copson plane and was applied to 30 cochlear implant patients and 30 patients with acquired cholesteatomas. Their ET anatomies were analysed and compared.ResultsIt was found that the new Ku-Copson mandibular fossa plane was a reliable and accurate plane for the measurement of ET angle and length. Furthermore, it was found that patients with acquired cholesteatomas have statistically significant smaller ET angles and shorter ET lengths when compared with patients with cochlear implants, of normal middle ear function.ConclusionThe newly proposed method utilising the right mandibular fossa as an anatomical landmark for ET angles and lengths measurement appears to be viable. The close proximity of this landmark to the middle ear means that it is highly likely to be captured in most cone-beam CT scans of the petrous temporal bones. This enables the retrospective examination ET angles and lengths to be conducted on CB CT scans. This study reports statistically significant difference in ET anatomy in patients with middle ear dysfunction.

Utilization potential of intraluminal optical coherence tomography for the Eustachian tube

Imaging the Eustachian tube is challenging because of its complex anatomy and limited accessibility. This study fabricated a fiber-based optical coherence tomography (OCT) catheter and investigated its potential for assessing the Eustachian tube anatomy. A customized OCT system and an imaging catheter, termed the Eustachian OCT, were developed for visualizing the Eustachian tube. Three male swine cadaver heads were used to study OCT image acquisition and for subsequent histologic correlation. The imaging catheter was introduced through the nasopharyngeal opening and reached toward the middle ear. The OCT images were acquired from the superior to the nasopharyngeal opening before and after Eustachian tube balloon dilatation. The histological anatomy of the Eustachian tube was compared with corresponding OCT images, The new, Eustachian OCT catheter was successfully inserted in the tubal lumen without damage. Cross-sectional images of the tube were successfully obtained, and the margins of the anatomical structures including cartilage, mucosa lining, and fat could be successfully delineated. After balloon dilatation, the expansion of the cross-sectional area could be identified from the OCT images. Using the OCT technique to assess the Eustachian tube anatomy was shown to be feasible, and the fabricated OCT image catheter was determined to be suitable for Eustachian tube assessment.

Developmental Anatomy of the Eustachian Tube: Implications for Balloon Dilation.

To describe the developmental anatomy of the eustachian tube (ET) and its relationship to surrounding structures on computed tomography. Case series with chart review. A tertiary care hospital. ET anatomy was assessed with reformatted high-resolution computed tomography scans from 2010 to 2018. Scans (n = 78) were randomly selected from the following age groups: <4, 5 to 7, 8 to 18, and >18 years. The following were measured and compared between groups: ET length, angles, and relationship between its bony cartilaginous junction and the internal carotid artery and between its nasopharyngeal opening and the nasal floor. The distance between the bony cartilaginous junction and internal carotid artery decreased with age between the <4-year-olds (2.4 ± 0.6 mm) and the 5- to 7-year-olds (2.0 ± 0.3 mm, P = .001). The ET length increased among the <4-year-olds (32 mm), 5- to 7-year-olds (36 mm), and 8- to 18-year-olds (41 mm, P < .0001). The cartilaginous ET increased among the <4-year-olds (20 mm), 5- to 7-year-olds (25 mm), and 8- to 18-year-olds (28 mm, P < .0001). The ET horizontal angle increased among the <4-year-olds (17°), 5- to 7-year-olds (21°), and 8- to 18-year-olds (23°, P≤ .003), but the ET sagittal angle did not statistically change after 5 years of age. The height difference between the nasopharyngeal opening of the ET and the nasal floor increased among the <4-year-olds (4 mm), 5- to 7-year-olds (7 mm), and 8- to 18-year-olds (11 mm, P < .0001). The ET elongates with age, and its angles and relationship to the nasal floor increase. Although some parameters mature faster, more than half of the ET growth occurs by 8 years of age, and adult morphology is achieved by early adolescence.

Eustachian Tube: Computed Tomography Analysis.

Eustachian tube has a major role in ventilation, drainage, and protection of the middle ear. High resolution computed tomography magnifies the role of preoperative imaging for detailed inner and middle ear anatomical information. The aim of this study was to find an applicable way by computed tomography imaging for assessment of Eustachian tube. The goal was to provide improved understanding of the Eustachian tube measurements and the relationship with middle ear in Egyptian population. Computed tomography measurements for Eustachian tube were done including; length of the bony and cartilaginous portions, Total length of Eustachian tube, as well as the width and height of the tympanic orifice of the Eustachian tube. Also, tubotympanic and Reid plane- Eustachian tube angles were measured. Within 200 studied ears in 100 subjects, the mean total Eustachian tube length was 40.19 ± 3.05 mm, mean length of the bony Eustachian tube was 11.69 ± 1.8 mm with significant longer Eustachian tube on left side, The mean length of the cartilaginous Eustachian tube was 28.5 ± 2.95 mm with significantly longer cartilaginous and total length in male (P < 0.0001). The mean width and height of the tympanic orifice of the Eustachian tube was 5.4 ± 0.79 and 4.85 ± 0.75 mm, respectively. The mean tubotympanic angle of the Eustachian tube was 148.11 ± 2.82°. The mean Reid plane- Eustachian tube angle was 27.69 ± 2.08° with significantly wider angle in males (P < 0.022). The Eustachian tube measurements can easily be obtained on computed tomography images, and are representative for the Eustachian tube anatomy. There is importance of extending computed tomography examinations beyond the middle ear cavity and the mastoids to the Eustachian tube in order to have more data on its condition and relations with different pathological conditions. Computed tomography provides improved understanding of the Eustachian tube measurements and relationship with middle ear structures.

Learning curves, undergraduate ENT, patulous Eustachian tube anatomy and managing necrotising otitis externa.

Learning curves, undergraduate ENT, patulous Eustachian tube anatomy and managing necrotising otitis externa.

Introduction

Introduction

Surgical Parameters for Minimally Invasive Trans–Eustachian Tube CSF Leak Repair: A Cadaveric Study and Literature Review

Cerebrospinal fluid rhinorrhea from a lateral skull base defect refractory to spontaneous healing and/or conservative management is most commonly managed via open surgery. Approach for repair is dictated by location of the defect, which may require surgical exploration. The final common pathway is the eustachian tube (ET). Endoscopic ET obliteration via endonasal and lateral approaches is under development. Whereas ET anatomy has been studied, surgical landmarks have not been previously described or quantified. We aimed to define surgical parameters of specific utility to endoscopic ET obliteration. A literature review was performed of known ET anatomic parameters. Next, using a combination of endoscopic and open techniques in cadavers, we cannulated the intact ET and dissected its posterior component to define the major curvature position of the ET, defined as the genu, and quantified the relative distances through the ET lumen. The genu was targeted as a major obstacle encountered when cannulating the ET from the nasopharynx. Among 10 ETs, we found an average distance of 23 ± 5 mm from the nasopharynx to the ET genu, distance of 24 ± 3 mm from the genu to the anterior aspect of the tympanic membrane and total ET length of 47 ± 4 mm. Although membranous and petrous components of the ET are important to its function, the genu may be a more useful surgical landmark. Basic surgical parameters for endoscopic ET obliteration are defined.

A Novel Functional Imaging Method of the Eustachian Tube

Objectives: (1) Image the Eustachian tube (ET) lumen by computed tomography (CT) scanning during ET function (ETF) testing, (2) characterize the differences in image quality for different scanning protocols, and (3) establish a novel research methodology for studying ET anatomy and physiology. Methods: In a cadaver head without craniofacial or otologic abnormalities, the tympanic membrane was perforated and ETF test was done using the forced response test (FRT) in a CT scanner. Opening (OP), steady (PS), and closing (CP) pressures were measured during forced air flow from the middle ear (ME) to the nasopharynx across the open ET. Temporal bone CT scans with continuous 0.625 mm thickness were done at a low and standard radiation doses before and during the steady flow (SF) phase of the FRT, after instilling iodinated contrast into the ME and ET, and after the FRT cleared the contrast from the ET. Image analysis was done using the CT scanner console software to view the ET and peritubal structures in standard views and after image reconstructions. Results: The average OP, PS, and CP values were 488 ± 249, 376 ± 101, and 211 ± 62 daPa. While a distinct ET lumen could not be demonstrated during the FRT done with air, CT with intra-luminal contrast clearly demonstrated the entire ET lumen. Post-contrast FRT demonstrated residual contrast outlining the lumen. Conclusions: Standard temporal bone CT doses provided a slightly better signal-to-noise than the low-dose CT for the air but not for the contrast. Combining ETF testing and CT imaging has potential research applications.

The Cephalic Index is not different among groups of children aged 36–48 months with chronic otitis media with effusion, recurrent acute otitis media and controls

ObjectivesThe Cephalic Index, an anthropometric measure of head shape, was reported to be different between individuals with and without signs of past or concurrent otitis media (OM). In this study, we compared the Cephalic Index and other measures of head shape among groups of children aged 36–48 months with a documented history of chronic OM with effusion (COME), recurrent acute OM (RAOM) and CONTROLS (few to no OM episodes) to test that hypothesis. MethodsIn 41 CONTROL, 36 COME and 42 RAOM children, Maximum Head Width, Maximum Head Length and Head Circumference were measured and the Cephalic Index (Head Width/Head Length×100) was calculated. The four measures were compared among the three groups using a General Linear Model that included group, sex and race as factors and age as a covariate. ResultsThere were no differences among groups in the Cephalic Index or Head Length. Head Width was significantly smaller in the RAOM when compared to the CONTROL group and Head Circumference was significantly smaller in the RAOM and COME groups when compared to the CONTROL group. For all measures, the distribution of values showed significant overlap among groups. ConclusionsThese results do not support the hypothesis that the Cephalic Index is different between young children with and without OM, but did document differences in Head Width and Circumference among groups. However, the large overlap in each measure for the three groups suggests that none capture sufficient information on Eustachian tube anatomy to predict disease presentation.

Pattern of Ear Diseases among Paediatric ENT Patient: An Experience from Tertiary Care Centre, Pokhara, Nepal

Introduction: Ear diseases are common in children mainly due to altered anatomy of Eustachian tube which is straighter in children as compared to that in adults. However, the cause of hearing loss in children is more varied, including the etiologies. This study was done to find out the pattern of ear diseases in paediatric age group attending ear, nose and throat OPD in a tertiary care centre in Pokhara, Nepal. Materials and Methods: This is a prospective study done in paediatric patients attending ENT OPD over a period of one year from January 2010 to January 2011. The diagnoses were made on the basis of history and clinical examination. Results were expressed in numbers and percentages. Results: Out of 1632 Pediatric ENT patients, 944 had ear diseases, 59.2% were males and 40.8% females. Wax (33.4%) was the commonest diagnosis followed by Chronic suppurative otitis media (24.3%) and Acute ottitis media (13%). Conclusion: Ear diseases are most common condition in ENT OPD among paediatric age group. Wax, CSOM and ASOM were the three most common ear diseases. J. Nepal Paediatr. Soc. 32(2) 2012 142-145 doi: http://dx.doi.org/10.3126/jnps.v32i2.5673

Finite Element Analysis of Eustachian Tube Function in Cleft Palate Infants Based on Histological Reconstructions

The prevalence of otitis media with effusion approaches 100% in infants with cleft palate (CP), and disease pathogenesis is believed to be caused by eustachian tube (ET) dysfunction. Quantify the functional consequences of ET anatomy in infant CP specimens, and identify the relative importance of various tissue biomechanical properties on ET function in infants with CP. Finite element models of ET anatomy and physiology were developed by using image analysis and three-dimensional (3D) reconstruction techniques. Models were developed using histological images of ET structures obtained from five infant CP specimens. The models were parameterized, and the effects of varying model parameters, which included tensor veli palatini and levator veli palatini force, ET cartilage, periluminal mucosal compliance, and hamular position on resistance to airflow through the tubal lumen, were determined. Of the evaluated parameters, only applied tensor veli palatini muscle force and compliance of the periluminal mucosa and cartilage tissues were significant predictors of resistance to airflow through the ET during muscle-assisted opening. Finite element models of ET function in the CP infant identified tensor veli palatini muscle force as a direct predictor and mucosal/cartilage compliance as an indirect predictor of ET opening during muscle-assisted lumen dilations. Hamular position and levator veli palatini force were not found to have an effect on ET function in CP infants.

Eya4-deficient mice are a model for heritable otitis media

Otitis media is an extremely common pediatric inflammation of the middle ear that often causes pain and diminishes hearing. Vulnerability to otitis media is due to eustachian tube dysfunction as well as other poorly understood factors, including genetic susceptibility. As EYA4 mutations cause sensorineural hearing loss in humans, we produced and characterized Eya4-deficient (Eya4(-/-)) mice, which had severe hearing deficits. In addition, all Eya4(-/-) mice developed otitis media with effusion. Anatomic studies revealed abnormal middle ear cavity and eustachian tube dysmorphology; thus, Eya4 regulation is critical for the development and function of these structures. We suggest that some human otitis media susceptibility reflects underlying genetic predisposition in genes like EYA4 that regulate middle ear and eustachian tube anatomy.

Head Shape and Abnormal Appearance of Tympanic Membranes

We examined 187 males to evaluate the hypothesis that short-headed persons more often have otitis media than long-headed persons. The subjects were seen as part of routine health screening before attending recreational summer camp. The photographic appearance of each tympanic membrane was judged on two separate occasions by an otolaryngologist who categorized them as "normal", "abnormal", or "cannot determine". The repeatability of the categorizations was fair: kappa = 0.44. Only the tympanic membranes categorized identically twice were used for data analysis. The left-right symmetry of the tympanic membrane categorizations was fair: correlation coefficient phi = 0.42. Subjects categorized as having bilaterally normal tympanic membranes were considered to have not had previous otitis media (N = 95). In contrast, subjects categorized as having at least one abnormal tympanic membrane were considered to have had previous otitis media (N = 13). Head length and width, measured by calipers, and the cephalic index (width divided by length) x 100 were determined for each person. On the average, the cephalic index of the normal subjects was lower than that for the subjects with otitis media (t = 3.06, p less than 0.005). These data support the suggestions of Pautow (1925) and Worley et al. (1987): dolichocephalic persons have otitis media less often than do brachycephalic persons. Though this association is not useful in clinical care of the individual patient, it may be considered a weak external manifestation of the different cranial base and eustachian tube anatomy found in persons with otitis media.