Panel 2: Anatomy (Eustachian Tube, Middle Ear, and Mastoid-Anatomy, Physiology, Pathophysiology, and Pathogenesis)

The effect of OSA on the negative pressure and acoustic compliance of middle ear cavity in children

OBJECTIVE

To explore the effect of obstructive sleep apnea (OSA) on the negative pressure and acoustic compliance of middle ear cavity in children.

METHODS

The clinical data of 258 children with suspected OSA, who complained of mouth breathing or snoring at night in the Department of Otolaryngology Head and neck surgery of the Second Affiliated Hospital of Xi'an Jiao Tong University from August 2020 to March 2022, were enrolled and analyzed retrospectively. The OSA and otitis media with effusion (OME) were determined by polysomnography (PSG) and acoustic immittance examination, respectively. Then, the parameters of tympanometry were compared between OSA and non-OSA children or among the children with various severity of OSA.

RESULTS

There was no significant difference in the incidence of OME between children with OSA and those with non-OSA (15.80% vs 11.80%, P = 0.422). Compared with non-OSA children, OSA children had lower negative pressure (-56.42 vs -12.38, P < 0.001) and higher acoustic compliance (0.45 vs 0.38, P = 0.030) in middle ear cavity. There were also significant differences in negative pressure and acoustic compliance among children with mild, moderate and severe OSA (P < 0.001; P = 0.001). However, only the absolute value of negative pressure was markedly decreased after surgical therapy accompanied with transformation from OSA to non-OSA (-156.67 vs -45.67, P < 0.05), while this was not observed for acoustic compliance (0.48 vs 0.40, P > 0.05).

CONCLUSION

OSA may have an adverse influence on the negative pressure and acoustic compliance of middle ear cavity in children.

The Effect of Anteriorly Located Sigmoid Sinus on Postoperative Hearing Gains: A Case-Control Study

There are many studies on the effects of temporal bone anatomical variations on a mastoid pneumatization. Considering the effects of the anatomic variations on mastoid pneumatization, it is considered that many anatomic variations may affect graft success rates and postoperative hearing threshold gains. We aimed to evaluate the effects of various anatomic variations on postoperative hearing gains among patients undergoing tympanoplasty. This retrospective cohort study conducted in a tertiary-care university hospital. This study enrolled 57 patients who underwent primary type 1 tympanoplasty operation using the temporal muscle fascia. The patients were divided into two groups as those with an anteriorly located sigmoid sinus (group 1), and no anatomic variation (group 2). Airway gain values at the frequency range of 250 Hz-8000 Hz and pure tone average (PTA) value were calculated preoperatively and at postoperative sixth month. The gains attained by the patient groups with anatomic variations were compared with group 2. There were significant differences between Group 1 and Group 2 in terms of the airway frequencies of 250, 500, 2000, 4000 Hz, and PTA value. We detected a lesser postoperative hearing gain in patients with an anteriorly located SS. We believe that anatomic variations that may affect middle ear and mastoid cavity may also affect postoperative hearing gain.

Intravascular Ultrasonography (IVUS)-A Tool for Imaging the Eustachian Tube?

The Eustachian tube (ET) has a key role in the pathogenesis of otitis media. Until now, there has been a lack of meaningful imaging methods to investigate the ET and its surrounding tissue. The aim of the current study was to investigate the possibilities of imaging the ET using Intravascular Ultrasonography (IVUS). ETs from sheep were scanned ex vivo and in vivo with different IVUS probes. In addition to native ETs, water was also used to improve coupling. Scans were subsequently compared with histological sections and a 3D model of the ET. In addition, ETs with a stenosis induced by a hyaluronic acid depot, after stent insertion, and during lower jaw movement were examined. The IVUS catheter was inserted into the ET lumen without any problems or injuries in all cases. The surrounding structures of the ET were identified in the ultrasound image. In addition, a change in size of the ET lumen due to movement was observed, and the position of the stent and the depot of hyaluronic acid could be examined. With the use of IVUS, a non-invasive possibility to examine the ET over its course with the adjacent structures as well as after different treatments is presented.

The relationship between dimensions of the Eustachian tube and acquired attic cholesteatoma

Objective

This study investigated the relationship between physical dimensions of the Eustachian tube and the emergence of primary attic cholesteatoma.

Methods

A total of 31 patients with unilateral attic cholesteatoma were selected for radiological comparison. Standard point measurements as well as specific measurements were performed using imaging software. The length, narrowest diameter and bony segment volume, and pharyngeal orifice diameter of both sides of the Eustachian tube (attic cholesteatoma and healthy control ears) were measured and compared.

Results

Comparison of the values did not reveal any statistically significant difference between the attic cholesteatoma ears and the healthy control ears in terms of: Eustachian tube height, narrowest diameter, bony segment volume or pharyngeal orifice diameter.

Conclusion

No statistically significant difference was found between the cholesteatoma ears and the healthy control ears in terms of the osseous Eustachian tube size. The findings indicate that the Eustachian tube bony segment dimensions and pharyngeal orifice diameter are not factors in attic cholesteatoma development.

Association Between Eustachian Tube Dysfunction Questionnaire-7 Scores and Eustachian Tube Function Test Results in Symptomatic Patients With a Normal Drum

Background and Objectives

We investigated the clinical validity of and correlation between the Eustachian Tube Dysfunction Questionnaire-7 (ETDQ-7) scores and the eustachian tube function test (ETFT) results in patients with a normal drum.

Subjects and Methods

The study included 49 patients (93 ears) with unilateral or bilateral ear fullness over >3 months. All patients were administered the ETDQ-7 survey and underwent the ETFT on the same day. The receiver operating characteristic (ROC) curve and the association between the results were statistically analyzed.

Results

ETDQ-7 scores were not significantly correlated with the ETFT results or with middle ear pressure. ETDQ-7 scores in patients with eustachian tube dysfunction (ETD) were significantly higher than those in patients with normal ETFT results (p=0.039) when ETD was defined as a pressure change <10 daPa on the ETFT. The area under the ROC curve was 0.631, with a sensitivity of 37.0% and specificity of 89.4%.

Conclusions

The ETDQ-7 has limited clinical significance in patients with ETD but a normal drum. Therefore, concomitant objective tests should be performed to diagnose patients with ETD.

Further Research Needed to Understand Relationship Between Tubarial Glands and Eustachian Tube Dysfunction

The pathophysiology of eustachian tube dysfunction (ETD) remains poorly characterized, and it may result in significant patient morbidity. A recent study has identified a collection of previously unidentified salivary glands in the nasopharynx that overlay the torus tubarius. While salivary gland tissue has been described in the nasopharynx, the newly discovered salivary gland tissue has been denoted tubarial glands (TGs) and theorized to be a distinct organ. The TGs have been suggested to aid in lubrication of the oropharynx and nasopharynx. However, the exact clinical significance of TGs is unknown. Given the proximity of the TG to the eustachian tube, it is possible that the TGs may be related to the development of ETD. Future studies of the TGs and related pathophysiology may improve approaches to developing future ETD treatments.

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.

Chronic obstructive Eustachian tube dysfunction: CT assessment with Valsalva maneuver and ETS-7 score

Chronic obstructive Eustachian tube dysfunction (ETD) is a common disorder of the middle ear. In recent years, two main diagnostic tools have become available: Eustachian tube score (ETS-7) and computed tomography (CT) combined with Valsalva maneuver. The aim of this study is to evaluate the outcomes of ETS-7 and CT in a group of patients affected by middle ear atelectasis with a strong suspicion of ETD. Three males and nine females, affected by middle ear atelectasis with retraction of the TM were enrolled. Each patient underwent to Eustachian tube dysfunction evaluation adopting the ETS-7 score and a temporal bone CT with Valsalva maneuver. The ears analyzed at steady state were divided into 2 groups: ETS<7 group and ETS≥ 7 group. The same division was applied for the ears analyzed after the Valsalva maneuver: ETS<7 group and ETS≥ 7 group. ETs were categorized as "well defined" (WD) and "not defined" (ND). The results of the analysis of the ETS-7 score in all 24 ears showed that 42% presented ETS ≥7, while 58% had ETS <7, indicating a diagnosis of ETD. In the ETS<7 group after Valsalva, ET was visualized in 33% of patients. In the ETS≥7 group it was WD in 29% after the Valsalva manoeuver. In both groups the comparison between the visualization of the ET before and after the Valsalva manoeuver did not present a statistical difference. No correlation emerged between ET evaluation with CT scan during Valsalva maneuver and ETS-7 score. It confirms that there is not a gold standard for the study of ET dysfunction.

Cone-Beam Computed Tomography Evaluation of the Eustachian Tube in Patients With Cleft Lip and Palate Compared With Normal Controls

The authors compared the morphological features of the Eustachian tube (ET) between patients with cleft lip and palate (CL/P) and normal controls using cone-beam computed tomography (CBCT). CBCT images of 51 CL/P patients (28 males and 23 females, mean age: 18.5 ± 8.0 years) and a control group of 52 patients (22 males and 30 females, mean age: 25.23 ± 10.65 years) were retrospectively evaluated. The Eustachian tube angle (ETA), Eustachian tube length (EL), and auditory tube angle (ATA) were measured on CBCT images. The ETA, EL, and ATA in the CL/P and normal control groups were 30.4 ± 6.2 and 36.7 ± 7.5°; 24.7 ± 3.7 and 27.7 ± 4.3 mm; and 142.4 ± 7.8 and 136.3 ± 4.1°, respectively. All between-group differences were statistically significant (all P < 0.05). There were no significant between-gender differences in either group (all P > 0.05). Continuous variables were compared using the Mann-Whitney U-test. The morphological features of the ET, measured via multiplanar reconstruction CBCT, differed between CL/P patients and normal controls. CBCT can be used to evaluate ET morphological features.

Audiometric Outcomes and Middle Ear Disease following Cerebrospinal Fluid Leak Repair

OBJECTIVE

To investigate audiometric outcomes and incidence of chronic ear disease following lateral skull base repair (LSBR) of cerebrospinal fluid (CSF) leaks.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary skull base center.

SUBJECTS AND METHODS

Consecutive adults undergoing LSBR of CSF leaks between 2012 and 2018 were reviewed. Audiometric data included mean air conduction pure-tone average (PTA), air-bone gap (ABG), speech recognition threshold (SRT), and word recognition score (WRS). The incidence and management of the following were collected: effusion, retraction, otitis media and externa, perforation, and cholesteatoma.

RESULTS

Seventy-three patients underwent transmastoid (n = 5), middle cranial fossa (n = 2), or combined approach (n = 67) for repair of spontaneous leaks (sCSFLs, n = 41) and those occurring in the setting of chronic ear disease (ceCSFLs, n = 32). ABG decreased 7.23 dB (P = .01) in sCSFL patients. Perforations (P = .01) were more likely in ceCSFL. No sCSFL patient developed a cholesteatoma, perforation, or infection. Effusions (n = 7) were transient, and retractions (n = 2) were managed conservatively in the sCSFL cohort. Eight ceCSFL patients required tubes, 3 underwent tympanoplasties with (n = 2) and without (n = 1) ossicular chain reconstruction (OCR), and 1 had tympanomastoidectomy with OCR.

CONCLUSION

Lateral skull base repair of CSF leaks maintained or improved hearing. Patients with preexisting chronic ear disease were more likely to require additional intervention to sustain adequate middle ear aeration compared to the sCSFL cohort. LSBR of sCSFL does not appear to increase risk for developing chronic ear disease.

Comparison of sonotubometry, impedance, tubo-tympano-aerography, and tubomanometry to test eustachian tube function

PURPOSE

There is currently no gold standard for the diagnosis of eustachian tube (ET) dysfunction. To provide an objective basis for the clinical diagnosis of ET dysfunction, we explored the characteristics of sonotubometry, impedance, tubo-tympano-aerography (TTAG), and tubomanometry (TMM) in volunteers with healthy ETs.

MATERIALS AND METHODS

Sonotubometry, impedance, TTAG, and TMM tests were performed in 110 healthy ears of 55 volunteers, and the characteristics of each ET test were compared and discussed.

RESULTS

The ET opening rate was compared between sonotubometry with dry swallowing, impedance with the Valsalva maneuver, TTAG with the Valsalva maneuver, and TMM with a nasopharyngeal pressure of 50 mbar in 100 (90.9%), 102 (92.7%), 99 (90.0%), and 104 (94.5%) ears, respectively; there was no significant difference among the four methods (P = 0.575). In sonotubometry, both dry swallowing and the Valsalva maneuver were superior to wet swallowing in terms of detecting ET opening (P = 0.000). In TMM, both the opening rate and the external auditory canal pressure were positively correlated with the nasopharyngeal pressure. Specifically, the opening rate and external auditory canal pressure increased with an increase in the nasopharyngeal pressure (r = 0.271, P = 0.000; r = 0.315, P = 0.000, respectively).

CONCLUSIONS

Sonotubometry, impedance, TTAG, and TMM have their own advantages and disadvantages. In clinical practice, the appropriate ET function test should be chosen on the basis of the patient's specific condition.

Otitis media with effusion in adults with patulous Eustachian tube

1.  Patients with patulous Eustachian tube (PET) were older, had a shorter duration of disease, and were more likely to develop bilateral otitis media with effusion.

2. Patients with PET were more likely to develop comorbidities of gastroesophageal reflux and allergies.

Multi-scale modeling of an upper respiratory airway: Effect of mucosal adhesion on Eustachian tube function in young children

BACKGROUND

The Eustachian tube is a collapsible upper respiratory airway that is periodically opened to maintain a healthy middle ear. Young children, <10 years old, exhibit reduced Eustachian tube opening efficiency and are at risk for developing middle ear infections. Although these infections increase mucosal adhesion, it is not known how adhesion forces alters the biomechanics of Eustachian tube opening in young children. This study uses computational techniques to investigate how increased mucosal adhesion alters Eustachian tube function in young children.

METHODS

Multi-scale finite element models were used to simulate the muscle-assisted opening of the Eustachian tube in healthy adults and young children. Airflow during opening was quantified as a function of adhesion strength, muscle forces and tissue mechanics.

FINDINGS

Although Eustachian tube function was sensitive to increased mucosal adhesion in both adults and children, young children developed Eustachian tube dysfunction at significantly lower values of mucosal adhesion. Specifically, the critical adhesion value was 2 orders of magnitude lower in young children as compared to healthy adults. Although increased adhesion did not alter the sensitivity of Eustachian tube function to tensor and levator veli palatini muscles forces, increased adhesion in young children did reduced the sensitivity of Eustachian tube function to changes in cartilage and mucosal tissue stiffness.

INTERPRETATIONS

These results indicate that increased mucosal adhesion can significantly alter the biomechanical mechanisms of Eustachian tube function in young children and that clinical assessment of adhesion levels may be important in therapy selection.

Evaluation of the Parameter "Mean Impedance" for Representing Eustachian tube Functions During Pressure Increase and Decrease in Pressure Chamber Measurements

HYPOTHESIS

The hypothesis of the study is that the mean impedance (MI) during compression and decompression provides additional information of the Eustachian tube (ET) function.

BACKGROUND

The continuous impedance measurement in a pressure chamber can provide valuable information about the opening function of the ET.

METHODS

Around 55 ear-healthy volunteers were examined in a pressure chamber. These were subjected to a decompression phase and a compression phase. The pressure change was constantly 20 kPa/min. Using evaluation software, the MI could be determined for both ears in each case for the phases of compression and decompression.

RESULTS

In 49 participants, we could interpret the data successfully. On average, an output value (without pressure changes) of the impedance of 0.58 ±0.11 Pa on the right side and 0.43 ± 0.1 Pa on the left side were measured. During decompression, 0.098 ± 0.05 Pa (right) and 0.087 ± 0.043 Pa (left) could be determined. For compression, values of 0.086 ± 0.044 Pa on the right and 0.079 ± 0.045 Pa on the left were detected. The retest reliability was higher with an intraclass correlation coefficient for the decompression MI of 0.833 than the 0.772 compression MI.

CONCLUSIONS

It is possible to measure MI in healthy subjects during compression and decompression. This value represents a good average in terms of the pressure tolerance of the middle ear. In future, studies will be required to determine whether MI will be a useful parameter in differentiating normal and abnormal ET function.

On the functional compartmentalization of the normal middle ear. Morpho-histological modelling parameters of its mucosa

BACKGROUND

Middle ear physiology includes both sound pressure transmission and homeostasis of its static air pressure. Pressure gradients are continuously created by gas exchange over the middle ear mucosa as well as by ambient pressure variations. Gas exchange models require actual values for regional mucosa thickness, blood vessel density, and diffusion distance. Such quantitative data have been scarce and limited to few histological samples from the tympanic cavity (TC) and the antrum. However, a detailed regional description of the morphological differences of the TC and mastoid air cell system (MACS) mucosa has not been available. The aim of the present study was to provide such parameters.

METHODS

The study included sets of three histological H&E-slides from 15 archived healthy temporal bones. We performed a comparison of the mucosa morphology among the following regions: (1) anterior TC; (2) inferior TC; (3) posterior TC; (4) superior TC; (5) MACS antrum; (6) superior MACS; (7) central MACS; (8) inferior MACS.

RESULTS

Regions (1)-(3), situated below the inter-attico-tympanic diaphragm, had the largest proportion of high respiratory epithelium, cilia and loose lamina propria within the mucosa, as well as the thickest mucosa and the largest diffusion distance. Regions (6)-(8), situated above the diaphragm, had the thinnest mucosa, the shortest distance to the blood vessels, together with the largest proportion of flat epithelium and very few cilia. Regions (4)-(5), still supradiaphragmatic, had intermediary values for these parameters, but generally closer to regions (6)-(8). The blood vessel density and the proportion of active mucosa were not significantly different among the regions.

CONCLUSION

Mucosa of regions (1), (2) and (3) represented a predominantly clearance-specific morphology, whereas in regions (4)-(8) it seemed adapted to gas exchange. However, the lack of statistically significant differences in blood vessel density and proportion of active mucosa indicated that all regions could be involved in gas exchange with the highest adaptation in the superior MACS. This pattern divides the middle ear functionally along the inter-attico-tympanic diaphragm rather than the anatomical division into TC and MACS.