Differential effects of mass-loading the eardrum and stiffening the middle ear on wideband absorbance.

The current work investigated the effects of mass-loading the eardrum on wideband absorbance in humans. A non-invasive approach to mass-loading the eardrum was utilized in which water was placed on the eardrum via ear canal access. The mass-loaded absorbance was compared to absorbance measured for two alternative middle ear states: normal and stiffened. To stiffen the ear, subjects pressurized the middle ear through either exsufflation or insufflation concurrent with Eustachian tube opening. Mass-loading the eardrum was hypothesized to reduce high-frequency absorbance, whereas pressurizing the middle ear was hypothesized to reduce low- to mid-frequency absorbance. Discriminant linear analysis classification was performed to evaluate the utility of absorbance in differentiating between conditions. Water on the eardrum reduced absorbance over the 0.7- to 6-kHz frequency range and increased absorbance at frequencies below approximately 0.5 kHz; these changes approximated the pattern of changes reported in both hearing thresholds and stapes motion upon mass-loading the eardrum. Pressurizing the middle ear reduced the absorbance over the 0.125- to 4-kHz frequency range. Several classification models based on the absorbance in two- or three-frequency bands had accuracy exceeding 88%.

Endoscopic trans-eustachian tube approach: identifying the precise landmarks, a novel radiological and anatomical evaluation.

PURPOSE: The endoscopic trans-eustachian approach (ETETA) is a less invasive approach to the infratemporal fossa (ITF), providing superior exposure compared to traditional transcranial approaches. The anatomy of the pharyngotympanic (eustachian) tube and adjacent neurovascular structures is complex and requires in-depth knowledge to safely perform this approach. We present a cadaveric and radiological assessment of critical anatomic considerations for ETETA. METHODS: Six adult cadaveric heads were dissected alongside examination of 50 paranasal sinus CT scans. Key anatomic relationships of the pharyngotympanic tube and adjacent structures were qualitatively and quantitatively evaluated. Descriptive statistics were performed for quantitative data. RESULTS: Anatomical and radiological measurements showed lateralization of the pharyngotympanic tube allows access to the ITF. The pharyngotympanic tube has bony and cartilaginous parts with the junction formed by the sphenoid spine and foramen spinosum. The bony part and tendon of the tensor tympani muscle were located at the posterior genu of the internal carotid artery. The anterior and inferior wall of the carotid canal was located between the horizontal segment of the internal carotid artery and petrous segment of the cartilaginous pharyngotympanic tube. CONCLUSION: The combination of preoperative radiographic assessment and anatomical correlation demonstrates a safe and effective approach to ETETA, which allowed satisfactory visualization of ITF. The morphological evaluation showed that the lateralization of the pharyngotympanic tube and related structures allowed a surgical corridor to reach the ITF. Endoscopic surgery through the pharyngotympanic tube is challenging, and in-depth understanding of the key anatomic relationships is critical for performing this approach.

Evaluation of the relationship of chronic otitis media with the Körner's septum, auditory tube angle, and tubotympanic angle.

PURPOSE: This study aimed to evaluate the relationships between chronic otitis media (COM) and the characteristics of Auditory tube (Eustachian) angle (ATa), tubotympanic angle (TTa), and Körner's septum (KS). METHODS: A retrospective research was conducted between January 2019 and October 2019. The computed tomography (CT) results and medical files of 210 patients were evaluated. According to CT results and medical files, the patients were evaluated regarding the presence of COM, KS, ATa, and TTa. RESULTS: There were 113 (53.81%) males and 97 (46.19%) females in the study group, and the mean age of the patients was 42.05 ± 10.77 years. The frequency of the KS was significantly higher in patients who were diagnosed with COM (35.66% vs. 7.41%, p < 0.001). The patients diagnosed with COM were found to have a narrower ATa and a wider TTa than the patients who were not diagnosed with COM. ATa was narrower and TTa was wider in patients with KS. The presence of KS and higher TTa value were considered as risk factors for COM (p < 0.001, p < 0.001, respectively) CONCLUSION:  Our findings indicate that ATa was narrower, TTa was wider and KS was more frequent in patients with COM. Analysis of risk factors demonstrated that increased TTa and the presence of KS were associated with increased risk for COM.

Changes of visualised Eustachian tube lengths by age and position: Radiologic study in sitting and supine positions using cone beam and conventional CT.

OBJECTIVES: Patulous eustachian tube (ET) has been characterised by the visualisation of full-length ET on computed tomography (CT) results. We wanted to investigate the changes of visualised ET lengths by age in supine and sitting positions. DESIGN: Retrospective study. SETTING: Tertiary care academic referral centre. PARTICIPANTS: One hundred subjects who underwent cone beam CT (CBCT) in a sitting position and conventional CT in a supine position for non-otitis-related or dental complaints. MAIN OUTCOME MEASURES: Visualised ET lengths from the nasopharyngeal orifice measured by different positions and ages. RESULTS: Subjects did not show visualisation of full-length ET throughout the study. The visualised ET lengths (9.0 ± 2.5 mm) of the CBCT group were significantly larger than those (6.8 ± 2.3 mm) of the conventional CT group (P < 0.0001).Women showed longer visualised ET lengths than men in CBCT group (P < 0.001). The visualised ET lengths of the CBCT group were consistent or slightly increasing as a function of age (P = 0.06); however, the visualised ET lengths of the conventional CT group decreased as a function of age (P = 0.001). The slopes of regression lines of the two groups were significantly different. CONCLUSIONS: When in the supine position, the ET lengths gradually shortened as the subjects got older, most likely due to venous engorgement and the collapse of surrounding tissues; this finding thus suggests that CT in a supine position is an inappropriate method to diagnose patulous ET. The visualised ET lengths by CBCT in a sitting position were consistent throughout the different ages of the subjects and may be used as a diagnostic test for patulous ET.

Cartilaginous Eustachian tube length and carotid canal dehiscence in children: a radiological study.

PURPOSE: The use of Balloon Eustachian tuboplasty (BET) for Eustachian tube dysfunction is increasing in adults but to a lesser extent in children. Despite growing experience, concerns remain that BET could theoretically cause carotid artery rupture, which may be more likely if there is carotid canal dehiscence adjacent to the bony Eustachian tube. This radiological study aims to assess the prevalence of carotid canal dehiscence and length of cartilaginous Eustachian tube in children. MATERIALS AND METHODS: 75 consecutive computed tomography scans of the petrous temporal bones performed in children were identified (150 carotid canals/Eustachian tubes). Two independent raters measured the length of the cartilaginous Eustachian tube and thickness of carotid canal wall. RESULTS: 8% of carotid canals had radiological dehiscence. Prevalence of carotid canal dehiscence on either side per child was 12%. Mean cartilaginous Eustachian tube length was 24.5 mm (SD 3.1 mm) and the minimum measured was 14.1 mm. The minimum length measured in a child over 3 years old (n = 65) was 18.1 mm. The mean thickness of bone of the carotid canal was 0.7 mm (SD 0.27 mm). There was a positive relationship between age and Eustachian tube length (Pearson's correlation coefficient = 0.622, p < 0.001). CONCLUSIONS: Carotid canal dehiscence in children has a low prevalence. Variation in the length of the cartilaginous Eustachian tube is low but is correlated with age. More research is required to define the indications, safety, efficacy and technical aspects of BET in children.

Critical distance between the cartilaginous Eustachian tube and the internal carotid artery.

During the last decade, endoscopic surgery of the Eustachian tube (ET) has been advocated for ET dilatory dysfunction and for patulous ET. The internal carotid artery (ICA) and the ET are closely related, and knowledge of their surgical anatomy has become essential. This study was designed to establish the anatomical relationships between the endoscopically critical area along the full length of the cartilaginous ET and its closest association with the ICA. The perpendicular distance between the ET lumen and the ICA was measured from head magnetic resonance images (MRI) at three levels: (A) cartilaginous and bony ET junctional point, (B) mid cartilaginous ET point, and (C) the nasopharyngeal orifice of the cartilaginous ET. Totally, 200 sides were reviewed in MRI scans of 229 patients. The mean distances for each level were: A = 4.3 mm (range 1.6-10.4 mm), B = 25 mm (range 9.0-61.6 mm), and C = 62 mm (range 34.3-84.4 mm). The perpendicular distance between ET and ICA at the nasopharyngeal orifice is large, but the distance shortens quickly while moving from the nasopharyngeal orifice of the ET to the junctional point of the ET. The potential for complications to the ICA rises as the surgical field moves closer to the isthmus of the ET because of the decreasing distance between the ET and the ICA.

The Effect of the Angle and Length of the Eustachian Tube on the Success Rate of Cartilage Type 1 Tympanoplasty.

OBJECTIVES: To explore the relationships between the angle and length of the eustachian tube (ET) (the ETa and the ETl) and the success rates of type 1 tympanoplasty. STUDY DESIGN: A retrospective clinical chart review. METHODS: In total, 160 patients (81 females and 79 males; average age, 37.12 ±â€Š12.46 years; age range: 18-65 years) who underwent cartilage type 1 tympanoplasty were included. Demographics and anatomical outcomes were recorded. The patients were divided into 2 groups in terms of anatomical success. The average ETa and ETl values of each group were measured on computed tomography images using a multiplanar reconstruction technique, and compared. A P value <0.05 was considered to reflect statistical significance. RESULTS: In group A, the ETa of diseased ears was 27.74 ±â€Š12.06° in males and 21.87 ±â€Š7.58° in females. In group A, the ETa of normal ears was 27.53 ±â€Š4.15° in males and 22.25 ±â€Š4.67° in females. In group B, the ETa of diseased ears was 28.85 ±â€Š6.19° in males and 22.91 ±â€Š5.65° in females. In group B, the ETa of normal ears was 27.71 ±â€Š5.23° in males and 23.72 ±â€Š6.20° in females. In group A, the mean ETl of diseased ears was 42.1 mm (28.9-45.1) in males and 38.2 mm (31.0-44.7) in females. In group A, the mean ETl of normal ears was 41.9 mm (29.2-45.8) in males and 37.4 mm (30.5-44.1) in females. In group B, the mean ETl of diseased ears was 40.8 mm (30.2-47.4) in males and 37.9 mm (31.8-45.2) in females. In group B, the mean ETl of normal ears was 41.6 mm (30.0-45.0) in males and 39.1 mm (30.0-43.7) in females. In group A, the ETa value of diseased ears did not differ between females and males, but in normal ears the ETa was higher in males than females (P =0.002 and P <0.05, respectively). In group B, no difference was evident between the ETa values of normal and diseased ears (P >0.05). No difference in the ETl values of diseased and normal ears, in either group, was apparent between females and males (both P >0.05). CONCLUSION: Neither the ETa nor the ETl affected the success rate of cartilage type 1 tympanoplasty. Further studies with larger numbers of patients are needed to compare anatomical outcomes after placement of various graft types and the effects of anatomical features of the ET on the success rate of type 1 tympanoplasty.

[The anatomical features of the middle ear exerting the influence on the formation of exudative otitis media in the breast-fed infants of different gestational age]. / Anatomicheskie osobennosti srednego ukha, vliiaiushchie na formirovanie ékssudativnogo srednego otita u grudnykh detei razlichnogo gestatsionnogo vozrasta.

The objective of the present study was to elucidate the anatomical features of the structure of the middle ear and eustachian tube in the breast-fed infants of different gestational age that may be responsible for the formation of exudates (fluids). We have examined 150 temporal bones obtained from the children's cadavers that were allocated to three groups as follows: 50 temporal bones obtained at weeks 26-30 weeks of gestation (group 1), 44 bones 31-36 weeks of gestation (group 2), and 37-40 weeks of gestation (full-term babies, group 3),The analysis of the data obtained on an individual bases revealed either increase or decreases in the selected characteristics of the eustachian tube in comparison with the respective average values as well as the well apparent predominance of a single change or a combination of alteration of several parameters in one case in 26-30 weeks and 31-36 weeks groups. No significant changes were found in group 1. It is concluded that the presence of a single change or a combination of two or three abnormal changes in the parameters of the bone structures of the eustachian tube can affect the development of the secretory process in the middle ear especially in the children born after 36 weeks of pregnancy.

Sex differences in adult craniofacial parameters.

PURPOSE: To compare normal male and female craniofacial parameters in adults and evaluate associations of sex and intercochlear distance with other craniofacial parameters. METHODS: In 60 normal adults (30 men and 30 women) who had no otitis media, craniofacial parameters were measured retrospectively on two-dimensional reformatted computed tomography scans. RESULTS: Compared with women, men had significantly greater mean osseous auditory tube length, cartilaginous auditory tube length, mastoid length, intercochlear distance, sella to posterior nasal spine distance, sella to basion distance, and nasopharynx sagittal area. The intercochlear distance was significantly correlated with mastoid depth, midpoint of the pharyngeal opening distance, sella to nasion distance, and nasopharynx sagittal area and inversely with angle of the auditory tube. Most men and women had Körner septum present, and mean thickness of Körner septum was significantly greater in men than women. CONCLUSIONS: Some craniofacial parameters, especially vertical parameters, differ with sex. These differences begin in childhood and continue in adulthood. Sex must be considered when planning a craniofacial morphologic study, and results of a craniofacial morphologic study should be evaluated with caution when there is no sex matching of the patient and control groups.

The selective odontoidectomy: endoscopic endonasal approach to the craniocervical junction.

OBJECTIVE: The resection of the odontoid process via an extended endoscopic endonasal approach has been recently proposed as an alternative to the microscopic transoral method. We aimed to delineate a minimally invasive endoscopic transnasal odontoidectomy and to describe the endoscopic anatomy of the anterior craniovertebral junction (CVJ). MATERIALS AND METHODS: The anterior CVJ of 14 fresh adult cadavers were selectively accessed via a binostril endoscopic endonasal approach using 0- and 30-degree endoscopes. RESULTS: The nasopharynx was widely exposed without removing any of the turbinates and without performing a sphenoidotomy. Occipital condyles and lateral masses of the C1 vertebra have been exposed inferiorly at lateral margins of the exposure, in addition to the foramen lacerum, which came into view at the superolateral corner of the operative field. The anterior arch of C1 and the upper 1.5 cm of the odontoid process of C2 have been removed via a minimally invasive endoscopic transnasal approach in all dissections. CONCLUSIONS: We propose the selective odontoidectomy as a minimally invasive method for the endoscopic endonasal removal of the odontoid process. By using this approach, turbinates and the sphenoid sinus remain unharmed. In addition, this approach may be used in exposing pathologies situated laterally at the anterior CVJ, such as the lateral masses of atlas and occipital condyles.

Anatomical Analysis of the Eustachian Tube in the Temporal Bone Through the Middle Fossa Window.

PURPOSE: This cadaveric anatomical study aimed to explore precise morphometric measurements of the eustachian tube (ET) and adjacent structures in the middle cranial fossa, focusing on identifying reliable surgical landmarks when traditional markers are compromised due to tumors or trauma. METHODS: Twenty-two temporal bones from 11 adult cadavers (mean age: 75.70 ± 13.75 yr, range: 40-90 yr; sex: 5 females and 6 males) were dissected bilaterally. Surgical tools, including an operation microscope, endoscope, and digital caliper, were used for meticulous measurements. Parameters such as ET dimensions, distances between key points, and relevant angles were quantified, ensuring precise anatomical data. RESULTS: ET width at the foramen spinosum (FS) level, the midline level, and the eustachian orifice level were measured as 2.18 ± 0.68, 2.42 ± 0.70, and 2.30 ± 0.74 mm, respectively. The distances from the zygomatic root (ZR) to FS, ET, superior semicircular canal (SSC), and internal carotid artery (ICA) were 29.61 ± 2.56, 23.28 ± 2.61, 26.53 ± 2.56, and 32.61 ± 3.69 mm, respectively. The angles between SSC-ZR-ICA and FS-ZR-ICA were measured as 36.57 ± 10.32 and 13.63 ± 3.72 degrees, respectively. No statistical difference was found between right-left or male-female measurements ( p > 0.05). CONCLUSION: The present study offers invaluable insights for neurotological surgeons performing middle fossa approaches. ET and ZR may serve as crucial reference points, enhancing surgical orientation and minimizing risks during complex procedures. These precise anatomical data may empower surgeons, ensuring safer and more confident middle cranial fossa operations, even in challenging clinical scenarios.

A Deep Learning Framework for Analysis of the Eustachian Tube and the Internal Carotid Artery.

OBJECTIVE: Obtaining automated, objective 3-dimensional (3D) models of the Eustachian tube (ET) and the internal carotid artery (ICA) from computed tomography (CT) scans could provide useful navigational and diagnostic information for ET pathologies and interventions. We aim to develop a deep learning (DL) pipeline to automatically segment the ET and ICA and use these segmentations to compute distances between these structures. STUDY DESIGN: Retrospective cohort. SETTING: Tertiary referral center. METHODS: From a database of 30 CT scans, 60 ET and ICA pairs were manually segmented and used to train an nnU-Net model, a DL segmentation framework. These segmentations were also used to develop a quantitative tool to capture the magnitude and location of the minimum distance point (MDP) between ET and ICA. Performance metrics for the nnU-Net automated segmentations were calculated via the average Hausdorff distance (AHD) and dice similarity coefficient (DSC). RESULTS: The AHD for the ET and ICA were 0.922 and 0.246 mm, respectively. Similarly, the DSC values for the ET and ICA were 0.578 and 0.884. The mean MDP from ET to ICA in the cartilaginous region was 2.6 mm (0.7-5.3 mm) and was located on average 1.9 mm caudal from the bony cartilaginous junction. CONCLUSION: This study describes the first end-to-end DL pipeline for automated ET and ICA segmentation and analyzes distances between these structures. In addition to helping to ensure the safe selection of patients for ET dilation, this method can facilitate large-scale studies exploring the relationship between ET pathologies and the 3D shape of the ET.

Evaluation of the Peritubal Region Between the Osseous Eustachian Tube and the Internal Carotid Artery: Usefulness of Oblique Temporal Computed Tomography with Valsalva Maneuver.

BACKGROUND:  As indications for surgical Eustachian tube (ET) procedures have been expanded, it is essential to understand the anatomy of ET surroundings for safe ET interventions. METHODS:  We evaluated the peritubal region using oblique planes of temporal computed tomography (CT) with the Valsalva maneuver and classified the peritubal region between the osseous ET and the internal carotid artery (ICA) into 5 types: 1. bony prominence; 2. air cell; 3. absence of peritubal structures (3a. thick canal [>0.5 mm], 3b. thin canal [<0.5 mm], 3c. dehiscence). RESULTS:  Bony prominence and air cell types were observed in 41.0% (50/122 ears) and 13.1% (16/122 ears), respectively. The ICA was located directly medial to the osseous ET in 39.4% (48/114 ears), of which thick and thin canal types were found in 23.8% and 15.6%, respectively. Internal carotid artery canal wall dehiscence was observed in 8 ears (6.6%). The shortest perpendicular distance between the osseous ET and ICA was 1.6 (range: 0.4-4.9) mm and 2.7 (range: 1.3-5.8) mm in the bony prominence and air cell types, respectively. Osseous ET-ICA distances were 1.2 (range: 0.6-3.6) mm and 0.4 (range: 0.1-0.5) mm in thick and thin canal types, respectively. CONCLUSION:  Distinct peritubal structure types were observed on oblique CT planes with Vasalva maneuver. Bony prominence and air cell types provide a protective layer between the osseous ET and ICA. Imaging information on peritubal structures may help to better understand the anatomy of the ET pathway, leading to safe and accurate surgical approaches to the osseous ET.

[Anatomy of the eustachian tube]. / Anatomie der Tuba Eustachii.

The auditory tube is part of a complex anatomical functional system, which even today is not completely explained. It plays a crucial role in the understanding of the pathogenesis of chronic middle ear infections and possible therapeutic interventions--particularly in infants. This paper summarizes the current knowledge of eustachian tube gross anatomy and histology, its peritubular structures and its topographic relationship to the internal carotid artery in adults. Anatomical aspects specific to infancy are related to their possible influence on tube function.

Surgical Closure of the Eustachian Tube Through Middle Fossa and Transmastoid Approaches: A Pilot Cadaveric Anatomy Study.

BACKGROUND: Cerebrospinal fluid rhinorrhea after temporal bone surgery involves drainage from the Eustachian tube (ET) into the nasopharynx, causing significant patient morbidity. Variable anatomy of the ET accounts for failures of currently used ET obliteration techniques. OBJECTIVE: To describe the surgical anatomy of the ET and examine possible techniques for ET closure through middle fossa (MF) and transmastoid approaches. METHODS: We described the surgical anatomy of the ET from the MF and transmastoid approaches in 5 adult cadaveric heads, measuring morphometric and surgical anatomy parameters and establishing targets for definite ET obliteration. RESULTS: The osseous ET measured an average of 19.53 mm (±1.56 mm), with a mean diameter of 2.24 mm (±0.29 mm). The shortest distance between the greater superficial petrosal nerve and the ET junction was 6.61 mm (±0.61 mm). Shortest distances between the ET junction and the foramen spinosum and posterior border of the foramen ovale were 1.09 mm (±0.24 mm) and 2.03 mm (±0.30 mm), respectively. Closure of the cartilaginous ET may be performed by folding it in on itself, securing it by packing, suturing, or surgical clip ligation. CONCLUSION: Definite obliteration of the cartilaginous ET appears feasible and the most definite approach to eliminate egress of cerebrospinal fluid to the nasopharynx using the MF approach. This technique may be used as an adjunct to skull base procedures where ET closure is planned.

The anatomic relationship around the horizontal segment of petrous internal carotid artery: a study based on reconstructed computed tomography angiography.

PURPOSE: The anatomic relationship around the horizontal segment of petrous internal carotid artery (ICA) is complicated. Relative researches on human patients using radiographic technique are scarce. It is essential to get adequate anatomic knowledge about this region for performing some bypass procedures. METHODS: Using the independent software Mimics, we prospectively studied the 0.45-mm-thick computed tomography angiography (CTA) images of 29 patients (58 sides). All patients' middle cranial fossa and related critical anatomic structures were reconstructed in 3D. Some measurements were established on the multiplanar reconstructed images, including the distance from foramen ovale and foramen spinosum to the petrous ICA; the distance from the lumen of cochlea to the edge of trigeminal impression and petrous ICA; and the length of the horizontal segment of petrous ICA. RESULTS: The horizontal segment of petrous ICA was surrounded by the trigeminal impression, the cochlea and the auditory tube spatially. On the multiplanar reconstructed CTA images, the average distances from foramen ovale and foramen spinosum to the petrous ICA were 4.1 mm and 5.8 mm, respectively; the average distance from the lumen of cochlea to the edge of trigeminal impression and petrous ICA were 8.2 mm and 2.0 mm, respectively; and the mean length of the horizontal segment of petrous ICA was 15.8 mm. CONCLUSIONS: Our results indicate adequate and reliable anatomic information can be obtained using reconstructed CTA on an individualized basis.

The cranial base and related internal anatomical features in Homo neanderthalensis and Homo sapiens.

The cranial anatomy of Homo neanderthalensis and Homo sapiens is well documented in the paleoanthropological and medical literature. However, there are few high-quality visual guides of their comparative morphology. We give here a detailed description of the anatomy of two important fossil specimens, La Chapelle-aux-Saints 1 and abri Pataud 1, based on high-resolution imaging data with each specimen representing the respective morphologies of H. neanderthalensis and H. sapiens. We describe the comparative morphology of external, endocranial, and internal characteristics of the cranium, with a focus on the petrous and tympanic portions of the temporal bone. This descriptive approach shows differences between our specimens, including in positions of cerebral components relative to cranial structures and patterns of dural sinus drainage. Numerous external and internal differences in the shape of the petrous temporal are also described, including its articulation with the tympanic bone and the orientation of the petrotympanic crest. The presence of a large protuberance between the osseous Eustachian tube orifice and carotid foramen in H. neanderthalensis suggests that the levator veli palatini muscle took origin more laterally than the dilator tubae arm of the tensor veli palatini muscle, a feature shared with H. sapiens. The overall pattern that emerges is one in which two species have undergone large-scale evolutionary changes in a functionally critical region. Such differences necessitate high-quality visualization and consideration of both internal and external morphology.

[Analysis of the morphological and functional characteristics of the eustachian tube using multislice CT and 320-row area detector CT].

Since impairment of functions of the Eustachian tube can lead to various diseases of the middle ear, it is considered that morphological and functional evaluation of the Eustachian tube is of clinical importance. However, it has been difficult to evaluate the Eustachian tube because it is located deep in the head, and most of the morphological studies conducted in the past have been based on the examination of specimens obtained from cadavers. One limitation of such studies is that dynamic processes in the living body cannot be evaluated. Multislice CT permits the Eustachian tube to be evaluate greater detail in living subjects and has provided new findings in morphological studies. Furthermore, the latest Area Detector CT systems allow dynamic studies to be performed. This report describes the basic principles of this examination technique and presents the latest findings obtained by analysis of the morphological and functional characteristics of the Eustachian tube using Multislice CT and Area Detector CT.

Morphological Analysis of the Adult Eustachian Tube: A Fresh-Frozen Human Cadaver Study.

OBJECTIVES: To evaluate the dilated Eustachian tube (ET) anatomy configuration using fresh human cadavers. METHODS: Fourteen ears from human cadavers were used to identify the ET configuration. The cadaver head was cut in the sagittal plane parallel to the nasal septum, dividing it into right and left sides. Silicone was then inserted into the ET through the nasopharyngeal orifice (NO). The volume and length of the impression were measured using 3D computed tomography imaging. RESULTS: The ET lumen was found to narrow from the NO to the isthmus, and the ET surface was concave anteriorly and convex posteriorly. The lower portion of the ET lumen was the most dilated and displayed a narrow top. The average volume of the ET impression was 1.4 ±â€Š0.5 ml. The total length of the posterior side was 30.5 ±â€Š3.6 mm, and that of the anterior side was 26.3 ±â€Š3.4 mm. The widest ET area of the NO was 10.1 ±â€Š0.9 mm in height and 8.0 ±â€Š1.5 mm in width. The preisthmus was 2.4 ±â€Š0.4 mm in height and 1.3 ±â€Š0.5 mm in width. The height and width were 8.37 and 5.33 mm at the 5 mm point from the NO, and 5.51 and 1.94 mm at the 20 mm point from the NO, respectively. CONCLUSION: We evaluated the configuration of the cartilaginous ET lumen, which is the main target of balloon dilation, and our findings may give insights into this dilation process and assist with the further development of ET balloons and stents.

Anatomical Features Around Eustachian Tube in Eosinophilic Otitis Media With Eosinophilic Sinusitis.

OBJECTIVES/HYPOTHESIS: This study investigated the relationships between anatomical findings around the eustachian tube (ET) and eosinophilic otitis media (EOM) accompanied by eosinophilic chronic rhinosinusitis (ECRS). STUDY DESIGN: This study employed axial, coronal, sagittal and oblique computed tomography. METHODS: Patients who underwent endoscopic sinus surgery at the Department of Otolaryngology, Toho University Medical Center Omori Hospital and were diagnosed with ECRS (106 patients) based on the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis study were included. Subsequently, the presence of EOM accompanied by ECRS in 212 ear sides was assessed, and preoperative sinus computed tomography was used to evaluate various anatomical findings, such as the development of the sphenoid sinus and mastoid cells at the apex of petrous bone, the angle and length of the ET, and the size of the tympanic orifice of the ET. The relationships between these anatomical findings and the presence of EOM were analyzed statistically. RESULTS: EOM accompanied by ECRS was associated with a high peripheral blood eosinophil count and bronchial asthma. Among anatomical factors, the absence of peri-ET cells or petrous apex cells, and a low angle and short length of the ET, were risk factors for the onset of EOM. CONCLUSION: Anatomical factors such as the absence of peri-eustachian cells or petrous apex cells, and low angle or short length of the ET, are risk factors for the onset of EOM along with ECRS. Assessment of these factors may help in preventing the future onset or aggravation of EOM. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E2689-E2695, 2021.