A method to assess the accuracy of sonotubometry for detecting Eustachian tube openings.

Sonotubometry is a simple test for Eustachian tube (ET) opening during a maneuver. Different sonotubometry configurations were suggested to maximize test accuracy, but no method has been described for comparing sonotubometry test results with those for a definitive measure of ET opening. Here, we present such a method and exemplify is use by an accuracy assessment of a simple sonotubometry configuration. A total of 502 data-sequences from 168 test sessions in 103 adult subjects were analyzed. For each session, subjects were seated in a pressure chamber and relative middle ear over- and under-pressures created by changing chamber pressure. At each pressure, the test sequence of bilateral tympanometry, bilateral sonotubometry while the subject swallowed twice, and bilateral tympanometry was done. Tympanometric data were expressed as the fractional gradient equilibrated (FGE) by swallowing and sonotubometric signals were analyzed to record the shape of detected sound signals. Tympanometric and sonotubometric tubal opening assignments were analyzed by cross-correlation. For the data sequences with FGE = 0 (n = 32) evidencing no tubal opening and one (n = 249) evidencing definitive tubal opening, detection of a sonotubometry sound signal during a swallow had a sensitivity and specificity of 74.2 and 65.6 % for identifying ET openings and an accuracy of 73.3 % for assigning ET opening/non-opening by swallowing. Measures of sound signal shape were significantly different between those groups. This protocol allows a sonotubometry accuracy assessment for detecting ET openings. For the test configuration used, accuracy was moderate, but this should improve as more sophisticated sonotubometry test configurations are evaluated.

Dissecting eustachian tube dysfunction: From phenotypes to endotypes.

OBJECTIVE: A broad spectrum of complaints, symptoms and manifestations has been assigned to Eustachian tube (ET) dysfunction (ETD). While such presentations may manifest as ETD phenotypes, underlying mechanisms are defined as endotypes. Our goal is to develop a diagnostic approach to differentiate the endotypes and guide clinicians in the workup and selection of treatments targeting the mechanism of ETD. STUDY DESIGN: Retrospective. SETTING: Tertiary care. SUBJECTS AND METHODS: Children and adults with suspected ETD were evaluated with a thorough examination, otomicroscopy, otoendoscopy, trans-nasal videoendoscopy and testing of passive and active ET dilatory properties. Degree of weakness in soft palate elevation and ET orifice widening (muscular weakness, ETD-M), presence of inflammation (ETD-I) and/or adenoid tissue impinging and restricting the ET opening (ETD-R) were assessed with video-endoscopy. The Forced Response Test, Inflation-Deflation Test and Pressure Chamber Test were used as applicable to quantify the degree and type of difficulty (Stricture, ETD-S or adhesive, ETD-A) or ease (patulous or semi-patulous, ETD-P/SP) in opening the ET, and degree of active muscular strength/weakness (ETD-M) was measured. Ears with normal function (ETF-N) findings were also identified. RESULTS: Video-endoscopic and ETF test results were obtained for 71 ears of 40 subjects (22 males, 18 females; 38 white, 2 black), with an average age of 22.9 ± 16.5 years (min:6.2, max:64.1). Videoendoscopy (21, 13, 33, 16, 13, 0, 0 ETs) and ETF testing analysis (20, 24, 0, 38, 0, 3, 13 ears) were categorized as ETF-N and the ETD endotypes ETD-S, ETD-R, ETD-M, ETD-I, ETD-A, and ETD-P/SP, respectively. Some phenotypes had features consistent with more than one endotype. CONCLUSION: A systematic approach of examination and testing may differentiate the specific underlying mechanisms, lead to a treatment targeted to the ETD endotype and may establish novel ways to diagnose and treat ETD.

Using Geometric Morphometric Analysis of Magnetic Resonance Imaging to Assess the Anatomy of the Eustachian Tube in Children with and without Otitis Media.

Otitis media (OM) is among the most common of childhood illnesses. It has long been hypothesized that children under age two are predisposed to OM due to differences in the anatomy of the Eustachian tube (ET), including the angle of the ET. OM in later childhood is less common but does occur, begging the question, are there shape differences in the ET that persist underlying later occurrences of OM? To answer this question, a novel method, which applied geometric and morphometric shape analysis to landmarks obtained from MRI data, was used. MRI scans were performed on 16 children (5 control, 3 cOME, and 8 rAOM) between 2011 and 2015. Sixteen landmarks representing the shape of the ET, cranial base, and palate were analyzed. The results of a Procrustes ANOVA indicate that the shape of the ET varies significantly (p < 0.01) between the OM and control groups. The shape differences between the OM group and the control are a medial and low attachment site of the tensor veli palatini (TVP) muscle, a posterior and high torus tubarius, and an anteriorly projected palate. These results support previous findings that a relatively horizontal ET is associated with a predisposition for OM. This study used a novel approach to examine anatomical differences in children with and without OM. First, the data set is unique in that it includes MRI scans of children with a confirmed OM diagnosis. Second, the use of MRI scans in craniofacial anatomy OM research is novel and allows for the collection of soft tissue landmarks and the visualization of soft tissue structures. Third, geometric morphometric shape analysis is a statistical method that captures shape differences, offering a more universal picture of nuanced changes within the entire set of landmarks, in contrast to more traditional linear and angular measurements used in prior OM studies examining craniofacial anatomy.

CT Imaging of Eustachian Tube Balloon Dilation: Method Development on Cadaver Heads.

Objective: To develop a methodology for the measurement of balloon dilation (BD) effects on Eustachian Tube (ET) structure using Computerized Tomography (CT) images. Methods: The BD of the ET was performed on three cadaver heads (five ears) through the nasopharyngeal orifice. The axial CT images of the temporal bones were obtained before dilation, while an inflated balloon was in the lumen of ET, and after balloon removal in each ear. Utilizing Dicom images captured by the ImageJ software 3D volume viewer function, the anatomical landmark coordinates of the ET were matched with their pre- and post-dilation counterparts, and the longitudinal axis of the ET was captured with serial images. The histograms of the regions of interest (ROI) and three different lumen width and length measurements were obtained from captured images. The densities of air, tissue, and bone were determined with histograms as a baseline to determine the BD rate as a function of increased air in the lumen. Results: The small ROI box included the area of prominently dilated ET lumen after BD and best represented the visually obvious changes in the lumen, compared to the ROIs that extended the wider areas (longest and longer). Air density was the outcome measure for comparison with each corresponding baseline value. The average increase in air density in the small ROI was 64%, while the longest and long ROI boxes showed 44 and 56% increases, respectively. Conclusion: This study describes a method to image the ET and quantify the outcomes of BD of the ET using anatomical landmarks.

Postpalatoplasty Eustachian tube function in young children with cleft palate.

OBJECTIVE: To characterize Eustachian tube function using the forced response test in young children with cleft palate with or without cleft lip after palatoplasty with tympanostomy tubes inserted prepalatoplasty and compare these results with those of a 1986 study that evaluated a similar population using identical methods. SETTING: Outpatient research clinic. PATIENTS/PARTICIPANTS: A total of 34 children with cleft palate were tested at an average age of 18.6 ± 4.0 months. MAIN OUTCOME MEASUREs: Passive and active measures for the forced response test. RESULTS: Of the sample, 13 ears could not be tested, and tests on 24 ears were incomplete. The forced response test showed that the passive Eustachian tube function parameters were similar to those of normal adults and children. The percentage of ears that showed tubal dilation with swallowing was 60%. The active resistance and dilatory efficiency were similar to those of a normal adult population. CONCLUSIONS: A 1986 study of Eustachian tube function in postpalatoplasty subjects with cleft palate (37 ears) aged 15 to 26 months documented Eustachian tube dilation with swallowing in 84% of the ears. In the present study, which focused on a similar population, the frequency of tubal dilation was 60%. Nonetheless, both frequencies are significantly greater than the dilation frequency of 27% reported for 56 ears of subjects with cleft palate tested between 3 months and 18 years with tympanostomy tubes inserted for persistent otitis media with effusion. This suggests that dilation during the forced response test may be a prognostic marker for those children with cleft palate who will resolve their ear disease at an early age.

Eustachian tube function in adults without middle ear disease.

OBJECTIVES: We sought to develop normative values for 5 eustachian tube function (ETF) test protocols in adults without otitis media (OM). METHODS: Twenty adults (19 to 48 years of age) without a recent history of OM (5 had OM in childhood) underwent unilateral myringotomy and were evaluated for ETF by use of the forced response, inflation, deflation, forcible "sniff", and Valsalva test protocols. When possible, these tests were repeated on a second day. RESULTS: Normative values for the parameters of these protocols in adult subjects without a recent history of OM were developed. Between-day data for the forced response test were highly correlated. A percentage of these tests showed eustachian tube "constriction" during swallowing--an abnormal condition. The percent reduction in applied pressures for the inflation and deflation tests was high, indicative of good ETF. Few subjects had a positive "sniff" test, whereas most had a positive Valsalva test, and the results for both tests were effort-dependent. CONCLUSIONS: Results of ETF tests in adults with and without recent OM have not been published. Normative data are now available for comparison with ETF test results in adults with OM. These protocols will be used to evaluate the efficacy of surgical procedures designed to improve ETF.

Change in Eustachian Tube Function With Balloon Dilation in Adults With Ventilation Tubes.

OBJECTIVE: Assess the changes in Eustachian tube (ET) function (ETF) with balloon dilation of Eustachian tube (BDET). STUDY DESIGN: Prospective cohort for repeated testing measures. SETTING: Clinical research center. PATIENTS: Eleven adults with at least one patent ventilation tube (VT) inserted for chronic ET dysfunction (ETD) and history of otitis media with effusion. INTERVENTIONS: Subjects with evidence of moderate to severe ETD on the side with a VT underwent unilateral BDET. MAIN OUTCOME MEASURES: Changes in ETF parameters after BDET measured by Forced Response Test (FRT), Inflation Deflation Test (IDT), and Pressure Chamber test. RESULTS: With the FRT at 11 ml/min, opening pressure (OP) decreased from 458 ±â€Š160 to 308 ±â€Š173 daPa and closing pressure (CP) from 115 ±â€Š83 to 72 ±â€Š81 daPa at the 3-month post-BDET visit. The IDT and Pressure Chamber test showed that the percentage of middle ear (ME) pressure gradient equilibrated with swallows improved from 28 ±â€Š34 to 53 ±â€Š5% for positive and from 20 ±â€Š28 to 38 ±â€Š43% for negative ME pressure. Images from the pre- and post-BDET functional CT scans did not show apparent changes in the anatomy. Comparisons of ETF test parameters pre- and post-BDET suggested that the ET was easier to open and stayed open longer after the procedure. However, during the limited duration of follow-up most subjects continued to have ETD, some requiring VT re-insertion after the study period. CONCLUSIONS: Adults with severe ETD may benefit from BDET, however ETD may not be completely resolved and patients may continue to need VTs.

Eustachian Tube Function in Adults with Ventilation Tubes Inserted for Otitis Media with Effusion.

OBJECTIVE: To investigate the eustachian tube (ET) function (ETF) in adults with ventilation tube (VT) inserted for the treatment of chronic otitis media with effusion (COME). MATERIALS AND METHODS: A total of 17 subjects with at least one VT were enrolled. A detailed history was obtained, and risk factors were assessed with questionnaires. Examination including nasopharyngeal video endoscopy and ETF tests, the forced response test (FRT), inflation-deflation test (IDT), and nasal/nasopharyngeal maneuvers (such as sniffing and Valsalva, Toynbee, and the diver's maneuvers) were performed. RESULTS: Averages for FRT were 580±333 daPa, 382±251 daPa, and 138±192 daPa for opening pressure, steady-state pressure, and closing pressure, respectively. Most subjects demonstrated minimal or weak active function during the FRT and IDT. While nasopharyngeal maneuvers changed the nasal/nasopharyngeal pressures, they did not significantly change the middle-ear pressures. These results indicated that most subjects had severe obstructive ET dysfunction (ETD) with an ET lumen that required high pressure differences to open and poor active muscular function inadequate for luminal dilation. These results imply that while any treatment to widen the ET, such as balloon dilation of the ET, is not expected to change the voluntary active muscular function, it may reduce the tissue pressures and resistance, thus facilitating luminal opening both passively and actively. CONCLUSION: Most patients with VT inserted for the treatment of COME appear to have an abnormal ETF with difficulty in passively opening the ET and weak active muscular function. Management of such patients addressing only passive properties may not be sufficient for the resolution of ETD.

Accuracy of the ETDQ-7 for Identifying Persons with Eustachian Tube Dysfunction.

Objective To compare the accuracy of the Eustachian Tube Dysfunction Questionnaire (ETDQ-7) in identifying people with eustachian tube (ET) dysfunction based on symptoms and an objective ET function test. Study Design Cross-sectional study. ObjSettingective Tertiary referral center. Subjects and Methods Fifty-five subjects with and without symptoms suggestive of ET dysfunction completed the ETDQ-7 and had their ET function evaluated by the percentage of middle ear pressure equilibrated after 5 swallows (PEq5) either during a pressure chamber test (intact tympanic membranes) or by the inflation-deflation test (nonintact tympanic membranes). ETDQ-7 score ≥14.5 and PEq5 <60% were used to define ET dysfunction, and sensitivity, specificity, and receiver operating characteristic curves were used to assess the level of association between ETDQ-7 scores and PEq5. Results Twenty-five asymptomatic subjects (group 1 = 15 females, 15 white; mean ± SD age, 32 ± 12.8 years) and 30 subjects with ET dysfunction symptoms (group 2 = 17 females, 25 white; age, 27 ± 16.3 years) were included in the analysis. ETDQ-7 sensitivity and specificity regarding correct group assignment were 70% and 100%, respectively, and with respect to predicting PEq5<60%, 54% and 78%. An area under the curve (AUC) of 0.68 (95% CI, 0.53-0.83) at the participant level and 0.64 (95% CI, 0.50-0.77) at the ear level indicated a moderate level of association that was lower, though not statistically significant, for nonintact tympanic membranes (AUC = 0.63 at the participant level and AUC = 0.49 at the ear level). Conclusion The ETDQ-7 score had a higher correlation with the ET dysfunction symptoms than with an objective measure of ET function.

A Novel Imaging Method for the Cartilaginous Eustachian Tube Lumen: Computerized Tomography During the Forced Response Test.

OBJECTIVES: In vivo imaging of the open cartilaginous Eustachian tube (ET) lumen by computed tomography (CT) scan during ET function (ETF) testing to establish new methodology. METHODS: Five adults underwent unilateral ETF testing of an ear with a nonintact tympanic membrane using the forced response test (FRT) to measure the opening pressure (PO), steady state pressure (PS), and flow conductance (CS). Then at baseline and during the PS phase of the FRT, a temporal-bone CT scan with continuous 0.625 mm thickness was obtained. Multiplanar oblique reformats along the axis of the ET were created, and point value and region of interest (ROI) Hounsfield unit measurements were recorded from the location of the ET lumen. RESULTS: At the FRT flow rate of 11 ml/min, the average PO, PS, and CS were 370.5 daPa, 119.6 daPa, and 0.16 ml/min/daPa, respectively. For flow rates of 23 and 46 ml/min, these values were 236.2, 204.2, 0.12 and 385.5, 321.1, 0.18, respectively. Although areas with lower attenuation were suggestive of air density, a distinct air-filled cartilaginous ET lumen could not be confirmed. CONCLUSIONS: While the current imaging parameters failed to resolve the air-soft tissue interface throughout the open cartilaginous ET, further advances in imaging may obviate this limitation.

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

Objective In this report, we review the recent literature (ie, past 4 years) to identify advances in our understanding of the middle ear-mastoid-eustachian tube system. We use this review to determine whether the short-term goals elaborated in the last report were achieved, and we propose updated goals to guide future otitis media research. Data Sources PubMed, Web of Science, Medline. Review Methods The panel topic was subdivided, and each contributor performed a literature search within the given time frame. The keywords searched included middle ear, eustachian tube, and mastoid for their intersection with anatomy, physiology, pathophysiology, and pathology. Preliminary reports from each panel member were consolidated and discussed when the panel met on June 11, 2015. At that meeting, the progress was evaluated and new short-term goals proposed. Conclusions Progress was made on 13 of the 20 short-term goals proposed in 2011. Significant advances were made in the characterization of middle ear gas exchange pathways, modeling eustachian tube function, and preliminary testing of treatments for eustachian tube dysfunction. Implications for Practice In the future, imaging technologies should be developed to noninvasively assess middle ear/eustachian tube structure and physiology with respect to their role in otitis media pathogenesis. The new data derived from these structure/function experiments should be integrated into computational models that can then be used to develop specific hypotheses concerning otitis media pathogenesis and persistence. Finally, rigorous studies on medical or surgical treatments for eustachian tube dysfunction should be undertaken.

Accuracy of CO2 conductance predicted using a morphometric model of the middle ear mucosa.

CONCLUSION: These results hold promise that morphometric analysis can be used to generate transMEM (middle ear mucosa) gas conductance estimates for MEM geometries representative of the shift from healthy to pathologic states (e.g. increased MEM thickness and capillary density). OBJECTIVES: Novel strategies to treat otitis media with effusion require a better understanding of how MEM geometry affects gas transport. Earlier studies developed techniques to empirically measure transMEM gas conductance and to estimate conductance using morphometric models of MEM geometry. We used chinchillas to determine the correspondence between experimentally measured transMEM CO2 conductance and that predicted by morphometric study of the MEM. MATERIALS AND METHODS: TransMEM CO2 conductance was measured unilaterally in 10 chinchillas; the animals were killed and the ME was removed and processed for morphometric analyses of MEM geometry. RESULTS: The average measured and estimated transMEM CO2 conductances were 4.87+/-2.30 x 10-10 and 1.75+/-0.29 x 10-10 mol/s/mmHg, respectively. The magnitude and direction of the estimate error were similar for all ears, suggesting a fixed, negative bias to the estimate. A theoretically consistent source for this bias was identified as the representation of the true diffusional length within a 3-D geometry using a 2-D modeling platform. Best estimate correction for this effect based on available data significantly reduced the estimate bias.

Correlations between videoendoscopy and sonotubometry of eustachian tube opening during a swallow.

OBJECTIVES/HYPOTHESIS: Describe the relationship between the magnitude of eustachian tube (ET) dilation during swallowing observed on transnasal videoendoscopy and quantified by sonotubometry. STUDY DESIGN: Descriptive observational study. METHODS: Simultaneous transnasal videoendoscopic and sonotubometric recordings were done on 33 adults with no middle ear disease. Briefly, microphones were placed in the ear canals, a 45° telescope introduced through one side of the nose to visualize and record ipsilateral ET movements, and the probe from a sound generator placed in the opposite nostril. At a generated nasopharyngeal sound level, ET movements and ipsilateral microphone signals were continuously recorded while the subject performed a series of three swallows. For each swallow, relational movements among ET structures observed on video recordings and characteristics of the sonotubometry signal envelope at the ear canal were quantified at three times: swallow onset (T1), maximum soft-palate elevation (T2), and maximum ET luminal dilation (T3). RESULTS: A total of 99 swallows were analyzed. The average medial rotation of the ET cartilage and lateral wall over the T1-T2 interval were -32.7 ± 14.9° and 7.2 ± 25.1°, and over the T2-T3 interval were 4.6 ± 7.7° and 6.2 ± 14.6°, respectively. The transtubal sound transmission during a swallow peaked at an amplitude of 30.5 ± 35.7 mV during the 572.5 ± 292.6 ms of elevated sound-pressure time. Correlational analysis documented significant linear associations between the relational measures of ET component movements from videoendoscopy and the signal envelope measures from sonotubometry. CONCLUSIONS: There is a direct linear relationship between the degree of ET luminal dilation visualized on videoendoscopy and represented in the sonotubometry signal envelope. LEVEL OF EVIDENCE: NA Laryngoscope, 126:2778-2784, 2016.

Craniofacial shape in children with and without a positive otitis media history.

OBJECTIVES: Past studies using traditional morphometric approaches have reported a handful of differences in craniofacial dimensions between individuals with and without otitis media (OM). In this study, a geometric morphometry (GM) approach was used to determine if craniofacial shape is different among children with no history of OM and a history of recurrent acute OM (RAOM) at two different ages. METHODS: Nineteen standard landmarks were identified on lateral cephalometric radiographs from 79 children (41 Control, 38 RAOM) at 4 years and 52 children (27 Control, 25 RAOM) at 6 years of age. Following Procrustes superimposition of the landmark coordinate data, comparisons of group differences in overall size and shape were performed. Discriminant function analysis and principal component analysis were used to determine which, if any, aspects of shape variation distinguished RAOM from Control groups. RESULTS: At 4 years of age, craniofacial size and shape were significantly different between RAOM and Control groups (p<0.05). Shape differences were evident in the relative positions of the mandible, cranial base, external acoustic meatus, sphenoid and palate. Those shape differences were not found in the 6-year old group. CONCLUSIONS: At 4 years of age, the RAOM and Control groups have distinct craniofacial morphologies, but by 6 years of age these differences have largely disappeared. This is consistent with the clinical observation that excess RAOM risk resolves around 6 years of age and the hypothesis that this resolution is partially a result of age-related craniofacial changes.

Eustachian Tube Function in 6-Year-Old Children with and without a History of Middle Ear Disease.

OBJECTIVE: To test the hypothesis that eustachian tube opening efficiency, measured as the fractional gradient equilibrated (FGE), is lower in 6-year-old children with no middle ear disease but a well-documented history of recurrent acute otitis media, as compared with children with a negative disease history (control). STUDY DESIGN: Cross-sectional study. SETTING: Tertiary care pediatric hospital. SUBJECTS AND METHODS: Bilateral eustachian tube function was evaluated in 44 healthy 6-year-old children (19 boys, 29 white). None had middle ear disease at the time of testing, but 23 had a history of recurrent acute otitis media. Twenty-one had no significant past otitis media. Eustachian tube function was measured with a pressure chamber protocol that established negative middle ear gauge pressures (referenced to the chamber pressure) and recorded that pressure before and after a swallow. FGE was calculated as the change in middle ear gauge pressure with swallowing divided by the preswallow pressure. Between-group comparisons of the preswallow pressures and FGEs were made with a 2-tailed Student's t test. RESULTS: FGE was independent of the preswallow middle ear gauge pressure. For the 39 and 44 evaluable ears in the control and recurrent acute otitis media groups, the mean preswallow pressures were -194 daPa (95% confidence interval [95% CI] = -211 to -177) versus -203 (95% CI = -216 to -190; P > .40), and FGEs were 0.32 (95% CI = 0.21-0.43) vs 0.16 (95% CI = 0.08-0.24; P = .016), respectively. CONCLUSION: In children with past recurrent acute otitis media, residual eustachian tube opening inefficiency is maintained after they have "outgrown" their middle ear disease.

Gene expression profiles of early pneumococcal otitis media in the rat.

OBJECTIVE: To define the gene expression patterns during the early phases of a bacterial middle ear infection in the rat model. METHOD: Using cDNA gene array technology, we profiled the mRNA expression of 1176 genes in a rat model of acute otitis media. We identified changes in gene expression two-fold or greater 12 and 48 h after bilateral ME inoculation with either tryptic soy broth (TSB) or Streptococcus pneumoniae in TSB. RESULTS: Transcripts of cytokines and cell adhesion molecules were up-regulated by 12 h, but returned to placebo transcription levels by 48 h. Three of six stress-response genes, including inducible nitric oxide synthase, GADD45 and heat shock protein 27 (HSP27) were up-regulated by 12 h, with HSP27 transcription levels continuing to rise through 48 h. All assayed transcription factors were up-regulated by 12 h, but only c-fos and c-jun up-regulation persisted to the 48-h time point. Up-regulation of apoptosis-related genes, except for bcl-x, was not evident until 48 h. These gene expression patterns reflected an early proinflammatory response consisting of cytokines, cell adhesion and stress-response molecules at 12 h followed by an up-regulation of apoptosis-related genes at 48 h. CONCLUSION: Downstream targets of several transcription factors, up-regulated transiently at 12 h, control secondary effects of S. pneumoniae infection, including apoptosis of neutrophils and mucosal epithelial cells, bone proliferation and promotion of leukocyte differentiation. These observations lead to a greater understanding of the early events in the pathogenesis of an AOM episode and highlight therapeutic targets, which may play a roll in the sequelae of AOM.

Quantitative description of eustachian tube movements during swallowing as visualized by transnasal videoendoscopy.

IMPORTANCE: Eustachian tube (ET) dysfunction predisposes ears to otitis media, tympanic membrane retraction, retraction pocket and perforation, or cholesteatoma. OBJECTIVE: To develop a method to quantitatively measure the eustachian tube (ET) component movements and their interactions captured by transnasal videoendoscopy of the ET during swallowing. DESIGN, SETTING, AND PARTICIPANTS: A blinded analysis of ET mechanics in 33 adults, aged 18 to 54 years, with no middle ear disease at present but without (group 1 [n = 16]) or with (group 2 [n = 17]) history of disease, conducted at a clinical research laboratory. INTERVENTIONS: Videoendoscopy of the ET orifice at the nasopharynx. MAIN OUTCOMES AND MEASURES: Eustachian tube component translations and structural interactions during a swallow and the between-group differences in those variables. After topical anesthesia of the nose, a 45° telescope was introduced unilaterally and focused on the ipsilateral ET orifice. A video recording of ET component movements was made during 3 swallows. Swallow and ET opening durations and times to selected events were calculated. Images at 3 time points were analyzed by measuring the apex angle, the medial-lateral luminal width, and the medial angles between a frame-normal horizontal line through the apex and fixed points on the torus and medial and lateral luminal walls. Linear and angular variables during a swallow were expressed as change from baseline. RESULTS: Luminal opening was driven by soft palate elevation-related medial rotation of the torus and medial wall, coupled with lateral wall fixedness. The magnitude of the change from baseline for most variables was statistically greater than 0. Swallow time, palatal elevation time, time interval between maximum palatal elevation, and maximum eustachian tube opening time were not different between groups 1 and 2. Opening time was longer (mean [SD], 0.49 [0.28] vs 0.67 [0.51] seconds; P = .03) in group 2. Higher magnitude of torus rotation (mean [SD], 36.05° [12.96°] vs 27.72° [9.45°]; P = .002) with maximum soft palate elevation in group 1 resulted in greater degree of eustachian tube orifice widening (mean [SD], 0.34% [0.47%] vs -0.02% [0.49%]; P = .001) compared with the resting position in that group. CONCLUSIONS AND RELEVANCE: This methodology has application in developing quantitative descriptions of ET mechanics in groups of persons without and with history or suspected ET dysfunction. A lesser degree of soft palate elevation during swallow that derives the ET medial lamina rotation and widening of the ET orifice may be associated with poor ET function and higher risk for otitis media. Videoendoscopic evaluation of the ET orifice may assist in diagnosing presence and mechanism of ET dysfunction.

Finite element analysis of active Eustachian tube function.

The inability to open the collapsible Eustachian tube (ET) has been related to the development of chronic otitis media. Although ET dysfunction may be due to anatomic and/or mechanical abnormalities, the precise mechanisms by which these structural properties alter ET opening phenomena have not been investigated. Previous investigations could only speculate on how these structural properties influence the tissue deformation processes responsible for ET opening. We have, therefore, developed a computational technique that can quantify these structure-function relationships. Cross-sectional histological images were obtained from eight normal adult human subjects, who had no history of middle ear disease. A midcartilaginous image from each subject was used to create two-dimensional finite element models of the soft tissue structures of the ET. ET opening phenomena were simulated by applying muscle forces on soft tissue surfaces in the appropriate direction and were quantified by calculating the resistance to flow (R(v)) in the opened lumen. A sensitivity analysis was conducted to determine the relative importance of muscle forces and soft-tissue elastic properties. Muscle contraction resulted in a medial-superior rotation of the medial lamina, stretching deformation in the Ostmann's fatty tissue, and lumen dilation. Variability in baseline R(v) values correlated with tissue size, whereas the functional relationship between R(v) and a given mechanical parameter was consistent in all subjects. ET opening was found to be highly sensitive to the applied muscle forces and relatively insensitive to cartilage elastic properties. These computational models have, therefore, identified how different tissue elements alter ET opening phenomena, which elements should be targeted for treatment, and the optimal mechanical properties of these tissue constructs.

Effect of surface tension and surfactant administration on Eustachian tube mechanics.

Development of otitis media has been related to abnormal Eustachian tube (ET) mechanics. ET is a collapsible tube that is periodically opened to regulate middle ear pressure and to clear middle ear fluid into the nasopharynx. The ability to perform these physiological functions depends on several mechanical properties, including the ET's opening pressure (P(open)), compliance (ETC), and hysteresis (eta). In this study, a previously developed modified force-response protocol was used to determine ET mechanical properties after experimental manipulation of the mucosal surface condition. Specifically, these properties were measured in the right ear of six cynomologous monkeys under baseline conditions after "washing out" the normal ET mucous layer and after instillation of a pulmonary surfactant, Infasurf. Removal of the normal mucosa did not significantly alter P(open) but did result in a decrease in ETC and eta (P < 0.05). Treatment of the mucosa with Infasurf was effective in reducing P(open) and increasing both ETC and eta to baseline values (P < 0.05). These results indicate that the mucosa-air surface tension can affect the overall ETC and eta properties of the ET. In addition, this study indicates that surfactant therapy may only be beneficial in patients with rigid or inelastic ETs (large P(open) and low ETC and eta).

Cathepsin gene expression profile in rat acute pneumococcal otitis media.

OBJECTIVES/HYPOTHESIS: Acute otitis media, often caused by infection with Streptococcus pneumoniae, is characterized by inflammation of the middle ear mucosa. A prominent feature of the host response to bacterial infection of the middle ear mucosa is an influx of inflammatory cells that contributes to the local pool of inflammatory mediators by releasing additional inflammatory chemicals, which in turn cause further tissue injury. The objective was to identify candidate effector and signaling molecules involved in acute otitis media pathogenesis caused by S pneumoniae infection. STUDY DESIGN: Male Sprague-Dawley rats were randomly assigned to 1 of 5 groups, including 1 control group without treatment, 2 placebo groups (12 and 48 hours) and 2 infected groups (12 and 48 hours). The rat middle ear was bilaterally inoculated with either 25 microL of tryptic soy broth (TSB group) or 25 microL of TSB containing approximately 1.24 x 10(9) cfu/mL of S pneumonias type 6A (SP group). Rats were killed at 12 and 48 hours after inoculation and the middle ear mucosa was collected. Total RNA was extracted and pooled from each group for gene expression assays. METHODS: Gene expression profiles for rat middle ear mucosa at 12 and 48 hours after S pneumoniae or placebo inoculation were constructed using microarray technology (Clontech Atlas Rat 1.2 Array, 1176 cDNAs). Genes of interest were further validated by real-time polymerize chain reaction. RESULTS: Middle ear mucosa expression of a gene cluster encoding the lysosomal cysteine proteases, cathepsins B (Ctsb), L (Ctsl), and K (Ctsk), was modified after S pneumoniae challenge. Specifically, at 12 hours, Ctsk and Ctsl messenger RNA that was abundantly expressed in the normal middle ear mucosa was decreased, whereas Ctsb transcript was induced. The changes in Ctsb and Ctsk gene expression were sustained at 48 hours. CONCLUSION: The constitutive expression of Ctsk and Ctsl messenger RNA in normal middle ear mucosa supports a function in the maintenance of middle ear mucosa homeostasis, and their downregulation as an early event in acute otitis media may reflect a disruption in that function. The induction of Ctsb messenger RNA in the infected middle ear mucosa suggests a role in early tissue injury; thus, Ctsb may represent a potential target for molecular diagnostics and/or rational intervention during the development of acute otitis media.