Effect of tensor veli palatini muscle paralysis on eustachian tube mechanics

Impact of a Modified Restoration of Tensor Veli Palatini on Hearing and Middle Ear Function in Cleft Palate Children-a Retrospective Study

BACKGROUND

Many children with cleft palate also exhibit hearing loss and middle ear dysfunction, which could last for years. There are still arguments on how to treat this problem. This study aimed to evaluate the impact of a modified restoration of tensor veli palatine (TVP) on hearing and middle ear function in the cleft palate children.

METHODS

This retrospective study was completed using records of the cleft palate children who received surgery in Peking Union Medical College Hospital from May 2013 to December 2020. They were divided into 2 groups: Group 1: children who received cleft palate surgery without specific restoration of TVP; Group 2: children who received palate surgery with a specific TVP restoration technique. Perioperative information was collected. The conductive auditory brainstem response and the 226-Hz tympanometry before and after the cleft surgery were compared intragroup and intergroup.

RESULTS

Totally 42 children were included in this study, 21 children in each group. There were no significant differences considering clinical characteristics between the 2 groups. The modified TVP restoration didn't increase operation time or complication compared with no TVP restoration. Statistically, neither the auditory brainstem response air conduction hearing thresholds nor the 226-Hz tympanometry results had significant differences between the 2 groups after the surgery.

CONCLUSIONS

This modified restoration of TVP was not time-consuming and did not increase complications. The beneficial effect of the modified TVP restoration on the hearing or the middle ear function of cleft palate children was uncertain around 6 months after surgery compared with no restoration.

Tensor Veli Palatinopexy as a Novel Treatment for Eustachian Tube Dysfunction: A Cadaveric Feasibility Study

OBJECTIVE

To demonstrate the feasibility of a novel procedure whereby a suture is placed transorally in the tensor veli palatini muscle to tighten it, thereby dilating the cartilaginous portion of the eustachian tube (ET).

STUDY DESIGN

The study design was a prospective cadaveric experiment to examine the feasibility of a novel treatment for ET dysfunction.

SETTING

Academic medical center in a research-oriented operating room with intraoperative computed tomography (CT) capabilities.

METHODS

Seven fresh-frozen cadaver heads were obtained, each of which was thawed for 36 hours prior to use. The preprocedural volumes of the cartilaginous ET were measured by filling the ET with an iodine-containing radiocontrast agent via the nasopharynx and then obtaining CT images. Submucosal flaps in the soft palate were raised, and sutures were placed in the tensor veli palatini bilaterally to increase tension. After completion of the procedure, contrast placement and CT imaging were repeated. Three-dimensional models of the ETs were created, and the volumes were measured and compared.

RESULTS

Of the 14 ETs evaluated, 13 showed an increase in postprocedure volume. On average, postprocedure volumes showed a 57% increase from preprocedure volumes (mean relative change, 57.1%; P = .013).

CONCLUSION

Placement of a tension-holding suture in the tensor veli palatini muscle can reliably dilate the cartilaginous portion of the ET. Such a procedure may be useful in the treatment of ET dysfunction.

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.

Multi-scale finite element modeling of Eustachian tube function: influence of mucosal adhesion

The inability to open the collapsible Eustachian tube (ET) leads to the development of chronic Otitis Media (OM). Although mucosal inflammation during OM leads to increased mucin gene expression and elevated adhesion forces within the ET lumen, it is not known how changes in mucosal adhesion alter the biomechanical mechanisms of ET function. In this study, we developed a novel multi-scale finite element model of ET function in adults that utilizes adhesion spring elements to simulate changes in mucosal adhesion. Models were created for six adult subjects, and dynamic patterns in muscle contraction were used to simulate the wave-like opening of the ET that occurs during swallowing. Results indicate that ET opening is highly sensitive to the level of mucosal adhesion and that exceeding a critical value of adhesion leads to rapid ET dysfunction. Parameter variation studies and sensitivity analysis indicate that increased mucosal adhesion alters the relative importance of several tissue biomechanical properties. For example, increases in mucosal adhesion reduced the sensitivity of ET function to tensor veli palatini muscle forces but did not alter the insensitivity of ET function to levator veli palatini muscle forces. Interestingly, although changes in cartilage stiffness did not significantly influence ET opening under low adhesion conditions, ET opening was highly sensitive to changes in cartilage stiffness under high adhesion conditions. Therefore, our multi-scale computational models indicate that changes in mucosal adhesion as would occur during inflammatory OM alter the biomechanical mechanisms of ET function. Copyright © 2016 John Wiley & Sons, Ltd.

Eustachian Tube Function

The fibrocartilaginous eustachian tube is part of a system of contiguous organs including the nose, palate, rhinopharynx, and middle ear cleft. The middle ear cleft consists of the tympanic cavity, which includes the bony eustachian tube (protympanum) and the mastoid gas cells system. The tympanic cavity and mastoid gas cells are interconnected and allow gaseous exchange and pressure regulation. The fibrocartilaginous eustachian tube is a complex organ consisting of a dynamic conduit with its mucosa, cartilage, surrounding soft tissue, peritubal muscles (ie, tensor and levator veli palatine, salpingopharyngeus and tensor tympani), and superior bony support (the sphenoid sulcus).

Successful Treatment of Autophonia with Botulinum Toxin: Case Report

Objectives:

We sought to treat autophonia due to a patulous eustachian tube using botulinum toxin.

Methods:

Because we assumed that the patulous eustachian tube was caused by abnormal activity of paratubal muscles (tensor and levator veli palatini muscles and salpingopharyngeus muscle), paralysis was performed via injection of botulinum toxin type A in a 45-year-old female professional musician who had had chronic unilateral autophonia for 20 years. In addition to a patient interview, an endoscopic examination of the nasopharynx (posterior rhinoscopy), ear microscopy, and impedance audiometry were performed to verify the diagnosis and the outcome after treatment.

Results:

The autophonia disappeared 1 week after treatment. Normalized tympanic ventilation was verified by impedance audiometry after 8 weeks. The period of symptom relief was 9 months.

Conclusions:

The administration of botulinum toxin type A provides a new option in the treatment of patulous eustachian tube. The reliability of this method and the effect of repeated injections remains to be proved in future studies.

The role of the tensor veli palatini muscle in the development of cleft palate-associated middle ear problems

Objective

Otitis media with effusion is common in infants with an unrepaired cleft palate. Although its prevalence is reduced after cleft surgery, many children continue to suffer from middle ear problems during childhood. While the tensor veli palatini muscle is thought to be involved in middle ear ventilation, evidence about its exact anatomy, function, and role in cleft palate surgery is limited.

This study aimed to perform a thorough review of the literature on (1) the role of the tensor veli palatini muscle in the Eustachian tube opening and middle ear ventilation, (2) anatomical anomalies in cleft palate infants related to middle ear disease, and (3) their implications for surgical techniques used in cleft palate repair.

Materials and methods

A literature search on the MEDLINE database was performed using a combination of the keywords “tensor veli palatini muscle,” “Eustachian tube,” “otitis media with effusion,” and “cleft palate.”

Results

Several studies confirm the important role of the tensor veli palatini muscle in the Eustachian tube opening mechanism. Maintaining the integrity of the tensor veli palatini muscle during cleft palate surgery seems to improve long-term otological outcome. However, anatomical variations in cleft palate children may alter the effect of the tensor veli palatini muscle on the Eustachian tube’s dilatation mechanism.

Conclusion

More research is warranted to clarify the role of the tensor veli palatini muscle in cleft palate-associated Eustachian tube dysfunction and development of middle ear problems.

Clinical relevance

Optimized surgical management of cleft palate could potentially reduce associated middle ear problems.

The role of tensor veli palatini muscle (TVP) and levetor veli palatini [corrected] muscle (LVP) in the opening and closing of pharyngeal orifice of Eustachian tube

CONCLUSION

This study developed an easy way to induce otitis media in an animal model and find the relation between tensor veli palatini muscle (TVP) and levetor veli palatini [corrected] muscle (LVP) in the opening and closing of the pharyngeal orifice of Eustachian tube. It was proved that otitis media is caused due to the dysfunction of Eustachian tube and the only muscle responsible for opening and closing of ETPO (Eustachian tube pharyngeal orifice) is TVP and LVP has no role in the opening and closing of the Eustachian tube pharyngeal orifice.

OBJECTIVE

To develop valid animal model for otitis media of effusion and to study the relation of paratubular muscles in the functioning of Eustachian tube.

METHODS

Two different methods were used to induce middle ear disease: (1) Excision of tensor veli palatini and levetor veli palatini [corrected] muscles (TVP and LVP); and (2) Injection of botulinum toxin type A on TVP and LVP.

RESULT

Otomiscroscopic, tympanograph, and pathological examination showed the presence of middle ear disease in those animals whose TVP was excised and paralyzed, but on those groups of animals whose LVP was excised and paralyzed, abnormalities were seen.

Denervation of the Tensor Veli Palatini Muscle and Effusion in the Tympanic Cavity

An English springer spaniel was presented for right-sided atrophy of the muscles of mastication, analgesia and paralysis of the face, and vestibular dysfunction. Neurological signs were consistent with a lesion involving the pons and rostral medulla resulting in deficits in the function of the trigeminal, facial, and vestibular nerves. MRI disclosed a right-sided extraparenchymal mass consistent with a trigeminal nerve sheath neoplasm that was compressing and invading the pons and medulla. Atrophy of the muscles of mastication, innervated by the trigeminal nerve, was also observed on MRI. Additionally, effusion was present in the ipsilateral tympanic cavity. Gross and microscopic evaluation of the right tensor veli palatini muscle (TVPM) was consistent with neurogenic atrophy. Effusion in the tympanic cavity was likely the result of an inability to open the auditory tube as a consequence of paralysis of the TVPM. Without the ability to open the auditory tube, gases present within the auditory tube and tympanic cavity may be absorbed, creating a negative pressure environment that leads to fluid transudation and effusion build up. To the authors' knowledge, this is the first report to document neurogenic atrophy of the TVPM with concurrent effusion in the ipsilateral tympanic cavity.

Investigation of middle ear pressure changes during prone position under general anesthesia without using nitrous oxide

PURPOSE

The effects of different body positions on the middle ear were reported in several studies, but there are no data about the effects on patients under general anesthesia. The aim of this study is to determine the effect of prone position on middle ear pressure (MEP) during general anesthesia without using nitrous oxide.

METHODS

Twenty patients under general anesthesia during prone position were included in the study. The performed anesthesia method was the same for all patients. Remifentanil was used for analgesia instead of nitrous oxide. MEPs were measured 5 times with a middle ear analyzer: before induction (BI), after intubation (AI), after turned to the prone position (PP1), at the end of the prone position (PP2), and after returned to the supine position (SP). Duration of prone position was also recorded.

RESULTS

Of the 20 patients were 11 women and 9 men with a 49 ± 13 mean age. BI-AI, AI-PP1, PP1-PP2, and PP2-SP comparisons of both MEPs were statistically significant (P < 0.0001). Right mean MEPs were BI, -1 ± 23 daPa; AI, 41 ± 51 daPa; PP1, 124 ± 76 daPa; PP2, 152 ± 59 daPa; and SP, 63 ± 29 daPa; whereas left mean MEPs were BI, -24 ± 55 daPa; AI, 28 ± 34 daPa; PP1, 132 ± 67 daPa; PP2, 162 ± 48 daPa; and SP, 70 ± 89 daPa. Significant increases were detected at the start and continuation of the prone position. The mean duration of prone position was 98 ± 51 per minute.

CONCLUSIONS

The significant MEP increases during the prone position under general anesthesia depend on a number of reasons. Among them are inhaler agents, pressure changes in mucosal blood vessels due to venous congestion, and the mastoid bone volume. Further researches are required to determine and explain the mechanisms of increase in MEP during prone position.

Functional evaluation of paratubal muscles using electromyography in patients with chronic unilateral tubal dysfunction

Eustachian tube dysfunction is closely related to the development of otitis media and result from several factors including inflammation within the nasal cavity and nasopharynx, adenoid hypertrophy, cleft palate and nasopharyngeal carcinoma. To some extent, eustachian tube dysfunction may be related to weakness of the paratubal muscles, such as the tensor veli palatini and levator veli palatini muscles. The aim of the study is to find out myogenic factors in eustachian tube dysfunction using electromyography (EMG), and to evaluate the clinical feasibility of EMG. Ten patients with unilateral eustachian tube dysfunction were included in this study. The healthy side of each patient was used as a control. EMG tests on paratubal muscles were conducted under the view of a 30° endoscope or fiberoptic laryngoscope. EMG on the tensor veli palatini showed decreased amplitudes on the affected side in one patient during phonation. EMG on the levator veli palatini showed decreased amplitudes on the affected side in two patients during both deglutition and phonation, one patient during phonation only, and two patients during deglutition only. The only patient who had decreased amplitude on EMG of the tensor veli palatini also had decreased amplitude on EMG of the levator veli palatini. In conclusion, although it is generally accepted that the tensor veli palatini plays a major role in opening the eustachian tube, reduced activity of the levator veli palatini may be related to eustachian tube dysfunction. When assessing eustachian tube function, EMG is useful for evaluating myogenic factors.

Synchronous endoscopy and sonotubometry of the eustachian tube: a pilot study

OBJECTIVE

To describe for the first time a method of recording of Eustachian tube (ET) function by simultaneous and synchronous endoscopy and sonotubometry and explore its advantages compared with the performance of these tests independently.

STUDY DESIGN

Observational study.

SETTING

Academic tertiary medical center.

PATIENTS

Eighteen healthy subjects.

INTERVENTION

Endoscopic nasopharyngoscopy with simultaneous, synchronous sonotubometry. Each subject performed three maneuvers: pronouncing the constant "k", swallowing and yawning.

MAIN OUTCOME MEASURES

The number of ET opening as a fraction of all efforts to open the tube, the duration of each opening and the sound intensity recorded by sonotubometry.

RESULTS

Six (35.3%) of 17 subjects used for data analysis did not open their ET during swallowing. Excluding nonopeners, the ET opened in 3 of 4 of the swallows. The average duration of opening of the ET during swallowing was 0.44 seconds. The ET does not open every time the endoscopic view notes dilation. A negative sound pressure wave was recorded in a number of instances, immediately preceding a swallow-related opening. Contraction of the tensor veli palatini muscle was essential for ET opening.

CONCLUSION

Simultaneous synchronous endoscopy and sonotubometry may improve the accuracy of either performed separately as an ET function measurement tool. Sonotubometry may prevent a false-positive endoscopy (ET viewed as open but no functional patency achieved). Endoscopy can lower the threshold considered as positive for sonotubometry. A negative pressure wave recorded by sonotubometry may reflect the ET role of clearing the middle ear of secretions toward the nasopharynx. This novel measurement technique provided additional evidence that the tensor veli palatini muscle provides the final opening action of the ET.

Three-dimensional finite element analysis of Eustachian tube function under normal and pathological conditions

A primary etiological factor underlying chronic middle ear disease is an inability to open the collapsible Eustachian tube (ET). However, the structure-function relationships responsible for ET dysfunction in patient populations at risk for developing otitis media (OM) are not known. In this study, three-dimensional (3D) finite element (FE) modeling techniques were used to investigate how changes in biomechanical and anatomical properties influence opening phenomena in three populations: normal adults, young children and infants with cleft palate. Histological data was used to create anatomically accurate models and FE techniques were used to simulate tissue deformation and ET opening. Lumen dilation was quantified using a computational fluid dynamic (CFD) technique and a sensitivity analysis was performed to ascertain the relative importance of the different anatomical and tissue mechanical properties. Results for adults suggest that ET function is highly sensitive to tensor veli palatini muscle (TVPM) forces and to periluminal mucosal tissue (PMT) elasticity. Young children and cleft palate subjects exhibited reduced sensitivity to TVPM forces while changes in PMT stiffness continued to have a significant impact on ET function. These results suggest that reducing PMT stiffness might be an effective way to restore ET function in these populations. Varying TVPM force vector relationships via changes in hamulus location had no effect on ET opening in young children and cleft palate subjects but did alter force transmission to the ET lumen during conditions of elevated adhesion. These models have therefore provided important new insights into the biomechanical mechanisms responsible for ET dysfunction.

Otologic and audiologic outcomes with the Furlow and von Langenbeck with intravelar veloplasty palatoplasties in unilateral cleft lip and palate

OBJECTIVE

Cleft palate increases the risk of chronic middle ear disease and hearing loss. The goal of this report was to determine which of two palate surgeries and which timing of palate surgery were associated with better otologic and audiologic outcomes in children with unilateral cleft lip and palate at 5 to 6 years of age.

DESIGN

Subjects were randomly assigned to the von Langenbeck with intravelar veloplasty or Furlow palate repair, to palate surgery at 9 to 12 months or 15 to 18 months of age, and to the Spina or Millard lip repair.

SETTING

Centralized, tertiary care craniofacial treatment center.

PATIENTS

A total of 673 infants with unilateral cleft lip and palate.

INTERVENTIONS

Palate and lip were repaired using established techniques. Serial otoscopic and audiometric evaluations were performed.

MAIN OUTCOME MEASURES

Hearing and otoscopic findings at 5 to 6 years old.

RESULTS

There were 370 children available for analysis. Hearing and need for tympanostomy tube placement did not differ by palatoplasty, age at palatoplasty, cheiloplasty, or surgeon. Risk of developing cholesteatoma or perforation was higher with Millard cheiloplasty (odds ratio  =  5.1, 95% confidence interval  =  1.44 to 18.11, p  =  .012). Type and age at palatoplasty were not significantly associated with either the rate of developing these sequelae or the rate of achieving bilaterally normal hearing and ear examinations.

CONCLUSIONS

Type of palatoplasty did not influence otologic and audiologic outcomes in 5- to 6-year-olds with unilateral cleft lip and palate. The potential influence of lip repair on otologic outcomes warrants further investigation.

Timing of tensor and levator veli palatini force application determines eustachian tube resistance patterns during the forced-response test

OBJECTIVES

The forced-response test (FRT) is used to assess eustachian tube (ET) function in patients with middle ear disease (otitis media). This test often documents a dynamic pattern of luminal dilation and constriction during swallowing which can be quantified as a function relating active tubal resistance with time. The goal of this study is to use a generalized finite element model (FEM) to test the hypothesis that the relative timing of muscle force application by the tensor veli palatini muscle (mTVP) and levator veli palatini muscle (mLVP) on the ET determines the form of active resistance functions.

METHODS

Seven resistance waveforms were obtained during the FRT in five adult subjects. A 2D FEM of the ET was constructed from an adult histological specimen and viscoelastic tissue mechanical properties were specified based on measurements obtained in each subject. Least-squared regression routines were used to vary the timing and magnitude of mTVP and mLVP force applications to the ET in order to match the active resistance functions recorded during the FRT.

RESULTS

Variation of muscle force timing and magnitude in the FEM simulations reproduced the seven active resistance waveforms with high fidelity. Early application of mTVP force in combination with mLVP force produced a waveform characterized by an initial dilation (low resistances) followed by lumen constriction (higher resistances), while delayed mTVP force application caused an initial lumen constriction followed by dilation.

CONCLUSIONS

These results indicate that the active resistance waveforms observed during the FRT reflect differences in the temporal pattern of mLVP and mTVP force application to the ET and emphasize that, like the mTVP, the mLVP functionally interacts with the ET. Results also indicate that in normal adults contraction of the mLVP promotes lumen constriction and that the initial lumen constriction is highly sensitive to the relative delay timing of mTVP and mLVP force application.

Finite element analysis of eustachian tube function in cleft palate infants based on histological reconstructions

INTRODUCTION

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.

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

The mastoid as a functional rate-limiter of middle ear pressure change

INTRODUCTION

The physiological function of the mastoid air cell system (MACS) with respect to middle ear (ME) pressure-regulation remains controversial because predictive mathematical models and experimental data to formulate and test hypotheses are lacking.

OBJECTIVE

A mathematical description of MACS volume effects on the rate of ME pressure change is presented; the agreement between published data and model prediction is examined for consistency with the hypothesis that the MACS acts as a functional rate-limiter of ME pressure change, and an explanation for the relationship between MACS volume and otitis media is discussed.

METHODS

The mathematical description shows that the value of a single, free parameter, termed the "MACS buffering efficiency" (M) determines if MACS volume affects the rate of ME pressure change caused by diffusive gas exchange. The MACS serves no rate-limiting function for M=0, acts as a gas sink for M>1 and acts as a gas reserve (rate-limiter) for M<1.

RESULTS

Fitting the model equation to published adult human data yielded an estimate for M of 0.2. This implies that larger MACS volumes are associated with lesser rates of change in ME pressure caused by diffusive gas exchange and lesser required frequencies of effective Eustachian tube openings to maintain near ambient ME pressures.

CONCLUSION

If well-controlled studies confirm M<1 for children and adults, larger MACS volumes will increase the time required to develop sufficient ME underpressures to cause otitis media by hydrops ex vacuo during transient or prolonged periods of Eustachian tube dysfunction.

Endoscopic examination of the eustachian tube: a step-by-step approach

OBJECTIVE

The aim of this study was to develop a step-by-step approach for endoscopic examinations of the eustachian tube on awake patients and to report anatomic and functional findings.

STUDY DESIGN

Prospective study.

SETTING

University hospital.

PATIENTS

Convenience sample of seven individuals without a history of ear disease.

INTERVENTION

Diagnostic transnasal-transpharyngeal videoendoscopy of the eustachian tube with 30- and 70-degree rigid Hopkins rod endoscopes, 2.5- and 0.8-mm, 0-degree flexible fiber endoscopes performed under local anesthesia in 12 eustachian tubes.

MAIN OUTCOME MEASURES

Utility of the various endoscopes for the diagnosis in the different parts of the eustachian tube; quality of vision and the patient's comfort during the procedure.

RESULTS

The 2.5-mm flexible endoscope was most useful for examination of the pharyngeal ostium and the cartilaginous lumen of the tube. The isthmus region could only be passed using an 0.8-mm fiberscope. In all cases, it was possible to insert the endoscope into the middle ear cavity. Eleven of the 12 tube examinations showed normal findings. The mobility of the tubal cartilage could be visualized with sufficient quality. In 50% of all examinations, application of local anesthesia via a tube catheter was necessary to make the procedure tolerable.

CONCLUSION

The presented approach allows an assessment of both anatomic and functional changes to the eustachian tube in awake patients. The assessment of middle ear structures is limited. To ensure a comfortable and safe procedure, the use of topical anesthesia in a supine position and, in certain cases, additional anesthesia via eustachian tube catheter is recommended.

Studies in otitis media: Children's Hospital of Pittsburgh-University of Pittsburgh progress report--2004

OBJECTIVES/HYPOTHESIS

The present Progress Report has summarized the key otitis media clinical trials and laboratory studies conducted since 1969 by investigators at the Children's Hospital of Pittsburgh-University of Pittsburgh (Pittsburgh, PA).

STUDY DESIGN

Review.

METHODS

Included in the discussion are the following: 1) studies of the epidemiology and risk factors; 2) anatomy and pathology of the eustachian tube-middle ear from human temporal bone histopathological specimens; 3) physiology and pathophysiology of the eustachian tube-middle ear in humans and animal models; 4) pathogenesis; 5) otitis media in special populations (e.g., patients with cleft palate, Native Americans, patients with Down syndrome); 6) microbiology; 7) diagnosis; 8) outcomes of randomized clinical trials that evaluated efficacy of nonsurgical and surgical methods of treatment and prevention; 9) studies of certain complications and sequelae (e.g., effect of middle-ear effusion on hearing, early child development, and the vestibular system; chronic suppurative otitis media). Also included are relevant summary tables and 256 references.

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 (Rv) 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 Rv values correlated with tissue size, whereas the functional relationship between Rv 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.