J. Douglas Swarts

Repair of the tympanic membrane with urinary bladder matrix

To test urinary bladder matrix (UBM) as a potential treatment for tympanic membrane (TM) healing and regeneration.

Cytokine Profiles in a Rat Model of Otitis Media With Effusion Caused by Eustachian Tube Obstruction With and Without Streptococcus pneumoniae Infection

Objective Cytokine expression was studied in a rat model of otitis media with effusion.

The Response of the Nasal Airway, Middle Ear, and Eustachian Tube to Experimental Rhinovirus Infection

This paper describes the longitudinal changes in nasal patency, mucociliary clearance rate, eustachian tube function, and middle ear pressure in a group of 40 volunteers infected with rhinovirus type 39. Thirty-two (80%) of the volunteers were judged to have had a cold based on the modified Jackson criteria. Common symptoms included malaise, nasal congestion, rhinorrhea, and sneezing that began on the day after challenge and peaked in intensity on days 3–5. Nasal patency evaluated by active posterior rhinomanometry and mucociliary clearance rate evaluated by the dyed sacharrin technique were significantly decreased following challenge. For nasal patency the effect was primarily limited to days 2–8 postchallenge, while abnormalities in clearance rate were documented for as long as 18 days postchallenge. A 50% increased incidence of abnormal eustachian tube function and a 30% increased incidence of abnormal middle ear pressures were observed for days 2–7 postchallenge with a gradual return to baseline by day 16. For mucociliary clearance, eustachian tube function, and middle ear pressure, but not nasal patency, these abnormalities were more pronounced in patients with a symptomatic cold. These results show that changes in nasal physiology resulting from a rhinovirus infection can be objectively quantified and that the resulting pathophysiology extends to anatomically contiguous structures such as the eustachian tube and middle ear.

A rat model of otitis media with effusion caused by eustachian tube obstruction with and without Streptococcus pneumoniae infection: methods and disease course.

OBJECTIVE: To describe the clinical and histopathologic progression of a rat model of otitis media with effusion caused by eustachian tube obstruction (ETO) with and without Streptococcus pneumoniae infection. METHODS: In 164 rats, the left, bony eustachian tube was approached via a ventral incision and obstructed with dental material. Then 108 rats were infected via an intrabullar injection with S pneumoniae. At 48 hours, the infected rats were treated for 5 days with ampicillin. All ears were evaluated by weekly otomicroscopy. On each of days 1, 2, 7, 21, 35, 56, and 112, four rats were killed for histologic study. All effusions were cultured for bacteria. RESULTS: Fourteen rats died of surgical complications; effusion resolved by 2 weeks in 9 rats. During the first few days, infected ears with ETO had bulging tympanic membranes, followed by tympanic membrane retraction, purulent effusion, and otorrhea (50%) over the next few weeks, whereas uninfected ears with ETO developed retraction and serous effusion during the same time frame. At later times, all ears with ETO presented with retraction and serous or serous-mucoid effusion. S pneumoniae was recovered only from the infected ears with ETO (days 1 and 2), with some colonization by nonpathogenic microorganisms observed equally in both groups of ears. Histology showed a typical acute inflammatory reaction in the challenged ears with ETO through day 14 and then a chronic inflammation for all ears with ETO. CONCLUSION: The experimental methods provoked reproducible pathologic signs similar to those for otitis media with effusion. Given the availability of rat-specific reagents, this model is well suited for studies of cytokine elaboration during disease pathogenesis.

In Vivo Observation with Magnetic Resonance Imaging of Middle Ear Effusion in Response to Experimental Underpressures

In this study, magnetic resonance imaging (MRI) was used to define, in vivo, the effect of acute middle ear (ME) underpressures on vascular permeability and the development of effusion. The MEs of four cynomolgus monkeys were unilaterally inflated with oxygen and carbon dioxide on different occasions and followed for a period of approximately 4 hours by tympanometry and MRI scanning. Carbon dioxide inflations caused the rapid development of ME underpressures of less than −600 mm H2O by 10 minutes. The MRI scans showed a progressive brightening of the ME and all associated air cells, indicative of the accumulation of effusion in three of the four experiments. An MRI contrast agent was administered to the vascular compartment during the course of the experiment and was rapidly transferred to the ME space, indicating vascular permeability to the agent. The contralateral, control side did not develop significant underpressures, effusion, or increased vascular permeability. Inflation with oxygen caused lesser underpressures and no accompanying changes in the MRI scans. These data support the hydrops ex vacuo theory and confirm the usefulness of MRI for in vivo documentation of the development of ME effusions and changes in vascular permeability of the mucosa in the experimental setting.

Role of the Mastoid in Middle Ear Pressure Regulation

Determine the role of mastoid volume in middle ear pressure (MEP) regulation. The hypothesis was that inert gas exchange between blood and middle ear (ME) is slower for larger mastoid volumes.

Relationship Between the Electromyographic Activity of the Paratubal Muscles and Eustachian Tube Opening Assessed by Sonotubometry and Videoendoscopy

OBJECTIVE To determine the role played by the tensor veli palatini and levator veli palatini muscles (mTVP and mLVP, respectively) in eustachian tube (ET) opening. DESIGN Prospective study. SETTING Research laboratories at a tertiary care hospital. PATIENTS Fifteen healthy adults with normal middle ears and documented ET openings. INTERVENTIONS Submental and ground surface electrodes were placed. After anesthetizing and decongesting the nasal passages, paired electromyographic needle electrodes were inserted into both the mTVP and mLVP on the test side. A microphone was placed into the ipsilateral ear canal and the probe from a sound generator was introduced into the opposite nostril. A 45° telescope was used on the test side to video-record the soft palate and ET movements while the individual swallowed. MAIN OUTCOME MEASURES Concurrent recordings of the ET openings by sonotubometry, the electromyographic activity for the LVP, TVP, and submental muscles, and video of the nasopharyngeal orifice of the ET during swallowing. RESULTS During swallowing, the median peak amplitude and duration of ET openings by sonotubometry were 30.6 mV and 196 milliseconds, respectively. For the mLVP and mTVP, the median peak amplitudes were 0.33 and 0.82 mV, and peak durations were 131 and 85 milliseconds, respectively. The mean onsets of muscle activity referenced to the sonotubometry peak amplitude were -0.28, -0.24, and -0.14 milliseconds for the mLVP, mTVP, and submental muscles, respectively. Video recording of ET movements were consistent with the timing of these events. CONCLUSIONS The mTVP activity had a shorter duration but greater amplitude than the mLVP activity and was associated with peak ET opening by sonotubometry. The mLVP activity occurred before that of the mTVP, the submental muscle group, and peak ET opening. The mLVP contractions were associated with movements of the soft palate, anterior ET orifice, and rotation of the ET cartilage.

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.

Eustachian tube function in older children and adults with persistent otitis media

OBJECTIVE Otitis media (OM) is most common in infants and young children. Despite a dramatic reduction in its incidence after the age of six, the disease still occurs in older children, adolescents, and may even persist into adulthood. The goal of this study was to identify characteristics of eustachian tube (ET) function in an older population which may underlie their persistent OM. METHODS Following a medical history and a head and neck examination, 38 subjects over 6 years of age (64 ears) had their ET function assessed with the forced-response test (FRT). Parameters derived from this test included opening and closing pressures as well as steady-state and active resistances. RESULTS Adenoidectomy had previously been performed in 71% of the sample. Clinically, 5% of these subjects had evidence of nasopharyngeal inflammation. The distributions of closing pressure and steady-state resistance were very similar to the distributions of the historic normal controls. The distributions of opening pressure and active resistance were highly skewed relative to the control sample. All study subjects had either abnormal opening pressures or high active resistance, with 79% having both abnormalities. CONCLUSIONS If nasopharyngeal inflammation and hypertrophied adenoids are significantly correlated to ET dysfunction and persistent OM, this sample should be free of middle-ear (ME) disease. However, these individuals suffer persistent OM due to ET dysfunction characterized by high opening pressures and high active resistances. The abnormalities underlying these skewed forced-response parameters must be identified and corrected if we are going to alleviate the ME disease in these and similar patients.

2. Eustachian Tube, Middle Ear, and Mastoid Anatomy; Physiology, Pathophysiology, and Pathogenesis

The following are publications related to the Eustachian tube (ET), middle ear and mastoid gascell system reported in the literature since the last research meeting in 2003. They include the anatomy, physiology, pathophysiology, and tests of function of the tube, as well as the role of the ET in the pathogenesis of middle-ear disorders and diseases. Also, these aspects related to the middle ear and mastoid gas-cell system are reviewed. But, there has been no attempt to include every publication reported during this time. This review is meant to be a state of knowledge since the last research conference up until the deliberations at this meeting. EUSTACHIAN TUBE