Type I allergic reactions of the middle ear and eustachian tube: an experimental study

To clarify the role of type I allergic reactions in etiology and pathogenesis of otitis media with effusion and to determine whether or not the middle ear is an allergic "shock" organ, we made animal models of nasal allergy in guinea pigs by passive sensitization with serum of homologous animals containing specific IgE antibodies. We also examined the eustachian tube, tympanic cavity (histologically), and tubal function after the induction of type I allergic reactions of the nose. However, the involvement of histologic changes was limited only up to the area near the pharyngeal orifice. The tubal dysfunction evoked by nasal allergic reactions was transient, culminating in no middle ear effusion. Upon direct antigen-challenge into the tympanic cavity, allergic changes were observed in the mucosa lining the tympanic bulla, even though no microscopic effusion was present. Findings of the present study suggest that type I allergic reactions of the nose are not an etiologic factor for otitis media with effusion, although the middle ear is potentially an allergic shock organ.     

Endoscopic laser surgery in combined nasopharyngeal and middle ear pathology in children with conductive hypoacusis

Endoscopic laser surgery on lymphoid structures of the nasopharynx near the pharyngeal opening of the auditory tube was made with Lazon-10P laser in 67 children aged 3 to 14 years with documented exudative otitis media (EOM). All the children had conductive hypoacusis. Children who had tympanogram of type B and in whom otoscopy detected exudate behind the tympanic membrane were subjected to one-stage laser tympanostomy in the anteroinferior quadrant of the tympanic membrane followed by transtympanic drug introduction into the tympanic cavity. Tympanostoma closed spontaneously 3 weeks later. Normal hearing recovered in all the children. Diagnostic endoscopy of the nasopharynx can reveal causes underlying dysfunction of the auditory tube. The results demonstrate high efficacy of the methods allowing elimination of mechanical occlusion of the auditory tube in the region of its pharyngeal opening with one-stage intervention on the middle ear.     

Consequences of a high-placed jugular bulb for the inferior ventilation pathway of the middle ear]

The evaluation and the correlation between the healthy and inflamed system of the mucosal folds of the middle ear demonstrate that there is a second "bottle neck" of the aeration pathways (the first being the Eustachian tube) in the region of the tympanic diaphragm with the tympanic isthmi - anterior and posterior -, the latter is more important for the ventilation of the epitympanum and antrum. Anatomical variations in this lower air-pathway as a high placed jugular bulb into the middle ear cavity endanger of course the undisturbed ventilation of the epitympanum and antrum in case of the infected and swollen mucosa and its folds.     

Experimental otitis media with effusion induced by lipopolysaccharide from Klebsiella pneumoniae: mucociliary pathology of the middle ear

We inoculated 100 micrograms/ml of lipopolysaccharide (LPS) from Klebsiella pneumoniae into the tympanic cavity of guinea pigs and examined the mucociliary pathology in the middle ear. Serous effusion was observed in the tympanic cavity of every animal on the first, third, and seventh day following the procedure, but the volume of the effusion had decreased to 0.2 ml on day 7. By that time, the ciliary activity in the opening to the eustachian tube within the middle ear had recovered to some extent, but in the middle ear distal to the opening no recovery was apparent. Our results show that cilia close to the eustachian tube play a more significant role in middle ear clearance than those in the middle ear distal to the tube. Compared with our previous study using 10 micron/ml of LPS, this study also demonstrates that inoculations with a higher concentration of LPS induces longer-term middle ear effusions.     

Partial oxygen tension of middle ear cavity in a normobaric environment

The present theory of eustachian tube function and middle ear ventilation posits that oxygen absorbed by the middle ear mucosa causes negative middle ear pressure which is relieved by periodic opening of the eustachian tube during swallowing and yawning. Measured by a PO2 sensor (Clark type) inserted into the middle ear cavity of normal adults through the eustachian tube, the partial oxygen pressure of the tympanic cavity was found 53.7 +/- 6.5 Torr (N:22). It was about one-third of ambient pressure (about 150 Torr), and showed no change when the eustachian tube was opened by swallowing. Our second study measured the effect of alterations in the systemic arterial blood oxygenation on middle ear gas exchange in 23 guinea pigs ventilated using 21% (room air), 50%, 70% and 100% oxygen at constant carbon dioxide blood gas tension. Partial oxygen tension (PO2) of middle ear cavity was measured by inserting a PO2 sensor into the tympanic bulla through a bore hole. The following results were obtained: (1) PO2 of the middle ear cavity was 39.3 +/- 2.2 Torr at room air, 42.2 +/- 0.84 Torr at 50%, 46.6 +/- 1.1 Torr at 70% and 54.5 +/- 3.7 Torr at 100% oxygen breathing. (2) There was a significant correlation between PO2 of the middle ear cavity and systemic arterial hyperoxygenation noted. Y = 30.79 + 0.056.X (r = 0.9440) (3) The rate of oxygen diffusion in the middle ear cavity was 2.665 x 10(-5) ml/min/cm2 and the rate of oxygen absorption in the middle ear space was 2.874 x 10(-5) ml/min/cm2. No significant difference between the rate of diffusion and that of absorption of oxygen in the middle ear cavity was noted. In our third study, electron microscopy shows that the submucosal capillaries of the human mastoid cells are structures which facilitate the intra- and extravascular transport of substances. It is known from these results that tympanic cavity pressure is kept equal to ambient pressure, or slightly higher to atmospheric pressure, by the respiratory function of the middle ear and mastoid cells so that outflow of air from the tympanic cavity to the pharyngeal orifice occurs during the ventilation of the eustachian tube at ambient pressure and inflow of air from the pharynx to the tympanic cavity is prevented in the absence of environmental pressure changes. The middle ear cavity has respiratory function, and in particular, such function of the mastoid cavity, which is larger in volume than the tympanic cavity, plays a significant role.(ABSTRACT TRUNCATED AT 400 WORDS)     

Two-port endoscopy of the middle ear: endoscopic anatomy

OBJECTIVES: To shed light on the endoscopic anatomy of the middle ear seen on 2-port endoscopy and to describe potential clinical applications. DESIGN: Anatomical structures were visualized by transmeatal or transtympanic rigid scopes of different angles and by a flexible scope in the eustachian tube. This arrangement ensured reciprocal guidance of the scopes and provided access to regions not seen otherwise. SETTING: The Department of Anatomy 1, University of Vienna, Vienna, Austria. MATERIALS: Forty tympanic cavities obtained from cadaver skulls without prior fixation were examined. Specimens did not show any abnormalities and were chosen without regard to age or sex. RESULTS: Depending on the angle of view, rigid transmeatal or transtympanic endoscopes provided a full view of the entire tympanic cavity except for the epitympanum, access to which was barred by the incudomallear joint, the mallear folds, and the tympanic chord, but the epitympanum was well visualized through the flexible, steerable, transtubal scope. CONCLUSIONS: Two-port endoscopy of the middle ear offers a full view of all structures in the tympanic cavity. The atraumatic transtubal approach to the tympanic cavity enhances the safety of transmeatal interventions and facilitates postoperative follow-up.     

Direct measurement of middle ear pressure through the eustachian tube

Summary We report a method for measuring middle ear pressure through the eustachian tube. We used a 1-mm-diameter micro-tip catheter pressure transducer (Mikro-tip) and inserted this into the tympanic cavity through the eustachian tube. In preliminary studies, we measured four normal ears, two ears with tubal dysfunction, one ear with a dry perforation and 13 ears with otitis media with effusion (OME). Among those ears with OME, three showed negative middle ear pressure, three slight positive pressure and one normal pressure. These findings suggest that our transtubal method is reliable and useful for measuring middle ear pressure.     

Direct measurement of middle ear pressure through the eustachian tube

We report a method for measuring middle ear pressure through the eustachian tube. We used a 1-mm-diameter micro-tip catheter pressure transducer (Mikro-tip) and inserted this into the tympanic cavity through the eustachian tube. In preliminary studies, we measured four normal ears, two ears with tubal dysfunction, one ear with a dry perforation and 13 ears with otitis media with effusion (OME). Among those ears with OME, three showed negative middle ear pressure, three slight positive pressure and one normal pressure. These findings suggest that our transtubal method is reliable and useful for measuring middle ear pressure.     

Tympanometry and laser Doppler interferometry measurements on otitis media with effusion model in human temporal bones.

HYPOTHESIS: The aim of this study is to investigate the effect of middle ear fluid and pressure on tympanic membrane mobility by using laser Doppler interferometry and to compare these results with tympanometry. BACKGROUND: Tympanometry has been commonly used for evaluation of otitis media with effusion, a middle ear disease with fluid in the cavity. However, this test lacks specific interpretations of middle ear disorders based on tympanometric data. Laser interferometry, as an advanced research tool to measure middle ear function, may provide knowledge of how tympanic membrane mobility is affected by middle ear fluid and pressure. METHODS: An otitis media with effusion model was created in seven human temporal bones for conducting experiments with tympanometry and laser interferometry. Middle ear pressure varied from -20 to +20 cm water, and the amount of fluid in the middle ear was gradually increased to fill the cavity. RESULTS: The displacement of the tympanic membrane measured by laser interferometry at selected frequencies decreased significantly corresponding to the middle ear air pressure changes. Tympanometry detected middle ear pressure by the change of tympanometric peak location, but the tympanogram shape was not affected by the middle ear pressure. The middle ear fluid was detected by tympanometry with as little as 0.3 mL, and laser interferometry was able to measure the displacement change of the tympanic membrane with 0.2 or 0.3 mL fluid at different frequencies. CONCLUSION: Laser interferometry can detect the effect of middle ear pressure and fluid on tympanic membrane movement as well as tympanometry does.     

Measurement of mucociliary function of the eustachian tube

Mucociliary function of the eustachian tube was measured with a radioisotopic method; 0.01 mL of a human serum albumin labeled with technetium 99m was instilled into the anterior part of the middle ear cavity either through a perforation or by puncturing the tympanic membrane, and its course was followed by a gamma-camera. In the normal eustachian tube, the velocity of the mucociliary transport was 0.7 to 1.1 mm/min. The mucociliary function was totally absent in chronic otitis media, in untreated secretory otitis media, and in the ear with a moist perforation of the tympanic membrane. The mucociliary transport returned to normal when the ear was clinically healed. It is assumed that the impairment of the mucociliary function of the eustachian tube and middle ear plays an important role in the pathogenesis of secretory otitis media and chronic ear discharge.     

Evolution of the epidermoid formation and its role in the development of the middle ear and tympanic membrane during the first trimester

In a study of 20 ears from embryos and early fetuses, 16 contained structures recognizable as precursors of the epidermoid formation (EF). The earliest were small, but later they took the form of a long epithelial bud which emanated from the tip of the tubotympanic recess or Eustachian tube. At a later stage still the EF protruded into the lumen of the Eustachian tube. The early formation of the tympanic membrane, the middle ear cavity and the osseous tympanic ring all take place in the vicinity of the EF precursor. It is possible that the EF precursor may act as an organizer, playing a prominent part in the migration of the first pharyngeal pouch towards the first branchial groove and the development of the middle ear and tympanic membrane.     

Congenital cholesteatomas of the middle ear in children: origin and management

Cholesteatomas (epidermoids) of the middle ear appearing medial to a normal tympanic membrane are identified in increasing numbers of young children. The evidence that these lesions are congenital in origin includes the young mean age of presentation, the normal appearance of the middle ear mucosa in almost all cases of small lesions, normal mastoid pneumatization documented by computerized tomography, the relatively large number of children with associated minor or major congenital malformations, and the consistent 3:1 ratio of males to females with the disorder in all of the large series reviewed. A direct relationship between congenital cholesteatomas (epidermoids) of the middle ear and the epidermoid formation is supported by the position of the epidermoid formation at a histologic transition zone in the anterior superior lateral quadrant of the tympanic cavity, which is also the site of greatest occurrence of congenital cholesteatomas. The epidermoid formation may not always involute and as it expands it would be expected to become visible medial to the tympanic membrane in the anterior superior quadrant. It seems evident that as the congenital cholesteatoma expands it can block the eustachian tube; during a bout of otitis media the tympanic membrane could perforate and the cholesteatoma could become secondarily infected. The congenital cholesteatoma in this situation would be difficult or impossible to distinguish from the more common acquired type.     

Antigenic as well as nonantigenic stimuli induce similar middle ear responses in the rat

OBJECTIVES/HYPOTHESIS: The observation that during otitis media many different types of micro-organisms have been cultured from effusions indicate that, once present in the middle ear cavity, most types of micro-organisms are able to trigger an inflammatory reaction leading to otitis media. The present study was designed to determine the middle ear response after injection of different substances into the middle ear cavity. STUDY DESIGN: To determine whether and to what extent an inflammatory response of the middle ear depends on the entering agent, the response in the tympanic cavity was studied by otomicroscopy and histological examination after inoculation of various substances. METHODS: Lewis rats were inoculated in transtympanic fashion either with live or heat-killed bacteria (pathogenic and nonpathogenic), Keyhole limpet hemocyanin, active charcoal, or saline. The mucosal response of the challenged middle ears was studied histologically. RESULTS: Irrespective of the inoculated substance, no essential differences in the mucosal response were found. The intensity of the inflammatory response was greater when live bacteria were inoculated. CONCLUSIONS: The present study demonstrates that any substance reaching the middle ear cavity is likely to induce otitis media. These observations emphasize the role of the eustachian tube as "porte d'entrée" in the pathogenesis of this disorder. Determination of specific aspects of the eustachian tube involved in protection or in facilitating bacterial translocation will be important for the understanding of the pathogenesis of otitis media and the subsequent development of new therapeutic strategies. In addition, elucidation of bacterial factors involved in the process of colonization and translocation will be of equal importance.     

The condition of the auditory tube in patients with chronic purulent otitis media as shown by computed tomography

Computed tomography (CT) was made in 25 patients with otitis media purulenta chronica (OMPC). Of them 17 patients had meso- or mesoepitympanitis and 8 patients had the history of radical operations on the ear. At first, CT was made of the temporal bone without contrast medium, then with instillation of the contrast medium through the external acoustic meatus and tympanic cavity into the auditory tube. Native computer tomograms of the temporal bones of 43 persons without any middle ear pathology were used as control. Non-contrast computer tomograms showed air in the lumen of the bone part of the auditory tube of all the examinees. It was impossible to obtain the image of the cartilage part of the auditory tube. None of 25 OMPC patients showed the signs of peritubal pneumatisation while it was registered in 14 healthy controls. By CT data, 14 of 17 patients with perforative OMPC had passable auditory tube even in aggravated inflammatory process, 3 of them had unpassable one. All 8 patients after radical operation had unpassable auditory tube. Thus, the method of contrast computer tomography determines passability of the auditory tube in the direction from the tympanic cavity to the nasopharynx and specifies the level of obstruction that is important to know before hearing improving operations of tympanoplasty type. Evaluation of the drainage function of the auditory tube basing on the time of evacuation of the contrast medium from the tympanic cavity to the nasopharynx was declared useless.     

The Tympanic Isthmus: Its Anatomy And Clinical Significance

The tympanic isthmus is a narrow passage between the tubotympanic cavity and the atticomastoid air space. Obstruction of the tympanic isthmus is frequent in various types of middle ear disease and causes significant air-diffusion disturbance within the temporal bone pneumatic system. Using large numbers of fresh temporal bone specimens, anatomical boundaries of the tympanic isthmus are defined and pathological variations are investigated. Embryological origin of the isthmus and pathophysiological implications of the tyrnpanic isthmus block are discussed. Among factors that cause obstruction of the tympanic isthmus are mucosal folds variations, inflammatory webs and exudate, retracted tympanic membrane, diseased attic mucosa, and cholesteatoma. Each factor is analyzed with representative specimen photographs. Clinical signs due to tympanic isthmus block often simulate or coexist with symptoms of eustachian tube obstruction. Surgical management of the tympanic isthmus block requires clear recognition of these disease processes. Understanding of the tympanic isthums as an anatomical entity is essential in the management of middle ear and attic disease.     

Functional repair of the eustachian tube

Endoscopy of the eustachian tube provides a new diagnostic potential for many problems of middle ear disease. The flexible fiberoptic system works from the nasopharynx as well as from the tympanic orifice, depending on the indications. It must be realized, however, that this is just the beginning of a new technique. Eustachian tube surgery plays a special role in connection with the new fiberoptic system. Preservation of the posterior bony canal wall and of the mucosal lining of the eustachian tube are the essentials of this modern approach.     

Morphological and functional changes in the tympanic cavity after its filling with platelet-enriched plasma (an experimental study)

This experimental study had the objective to estimate the functional state of the sound-conducting system of the middle ear and morphological changes in the tympanic cavity after its filling with platelet-enriched plasma (PEP) obtained by one-step centrifugation of the whole venous blood. The experiments were made on 6 pigs of the Large White breed. Tympanotomy performed under general anesthesia was followed by the introduction of a clot of platelet-enriched plasma into the tympanic cavity. The results of the study indicate that the ventilation function of the pharyngotympanic tube was fully preserved. The PEP clot was completely eliminated from the tympanic cavity within the first month after filling. Neither scars nor adhesions were recorded after the treatment with PEP. The study confirms the beneficial effect of using PEP for the support of the sound-conducting structures of the middle ear and stimulation of the regeneration processes after tympanoplasty.     

Can recurrent cholesteatoma be avoided?*

After closed operation techniques recurrences of cholesteatoma are often caused by retraction of squamous epithelium under the bony annulus, under which it spreads into the attic or the mastoid cavity. Consequently, retractions under the bony annulus can be avoided, if the annulus is removed. An endaural operation technique is described in which the superior and posterior bony ear canal wall is completely removed and the posterior wall is reconstructed by means of a meatal skin flap. As the oval window is often partly hidden by the frame of the tympanic membrane it is more favourable for the restoration of the sound conducting mechanism if the frame and surface of the tympanic membrane are extended backwards. This can be done by repositioning the posterior cutaneous ear canal wall and grafting the tympanic membrane with fascia. By doing this, the attic is incorporated into the ear canal. Should the factors which originally induced the development of the cholesteatoma remain effective and cause a new retraction, the full breadth of the posterior ear canal skin will retract into the exenterated mastoid cavity. An easily accesible open cavity and not a recurrence will be the result. In a follow-up study of 112 patients it was found that 67 of them had developed such an open cavity, which caused no serious problems.     

The role of laser assisted tympanostomy (LAT) in treating allergic children with chronic serous otitis media

OBJECTIVES: To assess various prognostic factors influencing the outcome in paediatric patients with serous otitis media, who have undergone laser assisted tympanostomy without ventilation tube placement. Emphasis is given to children with allergies who underwent the procedure. METHOD: Laser assisted tympanostomy was performed on a total of 130 ears (92 individuals) with chronic otitis media with effusion. To determine the quality of patient outcome, the following parameters were evaluated: external auditory canal anatomy, type of anaesthesia used, tympanic membrane and middle ear fluid characteristics, myringotomy size, a history of allergies and the laser device parameters. RESULTS: Multivariable statistical analysis demonstrated that the presence of allergies in children with chronic serous otitis media is significantly correlated with a poor outcome (P < 0.0047). Moreover, the presence of a thick tympanic membrane and/or high viscosity (glue) fluid in the middle ear cavity can also independently influence patient outcome (P < 0.025). Simultaneous adenoidectomy and/or tonsillectomy, type of anaesthesia (general versus local), external canal anatomy (wide or narrow) and sex, were not statistically important prognostic factors. The type of anaesthesia used, myringotomy size and the laser device parameters were not found to be associated with patient outcome. CONCLUSION: A history of allergies, the presence of a thick tympanic membrane and/or high viscosity fluid in the middle ear cavity are all contraindications for laser assisted tympanostomy without tympanostomy tubes, in children who suffer from chronic serous otitis media. The selection criteria for this procedure in the paediatric population are addressed in detail.