Tympanic membrane/middle ear pathologic correlates in chronic otitis media.

OBJECTIVE: To correlate pathologic findings of the tympanic membrane with pathologic changes in the middle ear cleft in chronic otitis media. STUDY DESIGN: Retrospective. MATERIAL AND METHODS: One hundred-fifty temporal bones from 97 subjects with chronic otitis media (defined as middle ear pathologic changes including granulation tissue, fluid, cholesteatoma, cholesterol granuloma, tympanosclerosis, and ossicular changes) were selected to correlate the presence of these middle ear pathologies with histopathologic changes of the tympanic membrane. The tympanic membrane pathologies included perforation, myringosclerosis, retraction, hemorrhage, fluid-filled cystic spaces, or dilated vessels. Temporal bones were also assessed for atelectasis. Fifty-six normal temporal bones were taken as controls for measurements. RESULTS: Significant correlations between tympanic membrane and middle ear pathology included myringosclerosis and granulation tissue, myringosclerosis and ossicular pathology, retraction and cholesterol granuloma, retraction and cholesteatoma, retraction and ossicular pathology, perforation and ossicular pathology, and hemorrhage and granulation tissue. Additive effects of some pathologies were also observed. Almost half the bones with middle ear pathology had no associated tympanic membrane pathology, whereas multiple pathologic changes in the tympanic membrane generally showed underlying multiple pathologic changes in the middle ear. CONCLUSION: When tympanic membrane pathology is detected otoscopically, its presence, alone or in combination, can be a strong indicator of underlying middle ear pathology. However, a normal-appearing tympanic membrane does not exclude the possibility of middle ear pathology. These findings suggest the need for other diagnostic tools such as multifrequency tympanometry and otoacoustic emissions to complement otoscopy for diagnosis of middle ear pathology, especially in a tympanic membrane that appears "normal."     

Shape and derived geometrical parameters of the adult, human tympanic membrane measured with a phase-shift moiré interferometer

The shape of the tympanic membrane is fairly complex and seems to be of significant importance in the coupling of the acoustic sound pressure in the external ear canal to the motion of the middle ear ossicles. A moiré shift interferometer was used to measure with great precision the shape of the external surface of human tympanic membrane. The dense matrix of z(x,y) values thus obtained is used to calculate different geometrical parameters (area, curvature, ...). We show further how the same data can be used to specify exactly the shape of the tympanic membrane in a mathematical finite-element model of the middle ear.     

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.     

Pathogenesis of experimental aural cholesteatoma in the chinchilla

Histopathological observation of celloidin serial sections of the chinchilla middle ear after treatment with propylene glycol disclosed the development of severe inflammation of the middle ear mucosa and tympanic membrane, papillary proliferation of the epidermis of the tympanic membrane and external auditory meatus, and retraction and adhesion of the tympanic membrane. The findings for the tympanic membrane, impedance testing and histopathological examination suggested that there were two types of acquired cholesteatoma formation, probably with a difference in the pathogenesis. In one type, the proliferated epidermal layer of the tympanic membrane penetrated into the middle ear cavity making tympanic perforations. In the other type, there was progressive retraction of the tympanic membrane forming a retraction pocket. We discuss the two different patterns of cholesteatoma development.     

Temporal bone histopathology in chronically infected ears with intact and perforated tympanic membranes.

Chronic suppurative otitis media has been clinically defined as a chronic discharge from the middle ear in the presence of a perforation of the tympanic membrane. However, irreversible tissue pathology in the middle ear or mastoid can occur behind an intact tympanic membrane. One hundred forty-four human temporal bones with chronic otitis media were divided into two groups: those with perforated (28) and those with nonperforated (116) tympanic membranes. The histopathological findings of their middle ears were compared. Granulation tissue in various degrees was the most prominent pathological feature. It was observed in 96% of temporal bones with perforation of the tympanic membrane, and in 97% of those without perforation. Also found were ossicular bony changes (96% with perforation; 90.5% without), middle ear effusion (93% with perforation; 89% without), cholesterol granuloma (21% with perforation; 12% without), cholesteatoma (36% with perforation; 4% without), and tympanosclerosis (43% with perforation; 20% without). This study shows that the histopathological changes of the middle ear are similar in temporal bones with and without perforation of the tympanic membrane. The clinician should, therefore, be aware that an intact tympanic membrane does not necessarily preclude the presence of gross pathological changes of the middle ear cleft.     

Tympanic membrane structure during a Staphylococcus aureus-induced middle ear infection. A study in the rat middle ear

In response to a Staphylococcus aureus-induced middle ear infection the tympanic membrane showed infiltration of polymorphonuclear granulocytes, lymphocytes, and macrophages and increased areas covered by ciliary and secretory epithelium. These reactions, which were comparable to the cellular and mucociliary responses seen in the middle ear mucosa during infection, were restricted to the pars flaccida and to predominantly the annular and manubrial regions of the pars tensa. This showed that the greater part of the tympanic membrane, where the lamina propria is composed of collagenous bundles and only very thin layers of loose connective tissue, is hardly affected by or barely responds to the inflammatory stimulus.     

Cholinergic innervation of the guinea pig tympanic membrane.

While cholinergic nerve fibers of the parasympathetic system have been demonstrated in the middle ear mucosa, such innervation of the tympanic membrane has never been shown. Such fibers may prove important since the tympanic membrane may be one of the initial sites of effusion production, and since parasympathetic innervation is thought to be involved with middle ear effusion. To demonstrate cholinergic innervation, we have used modified direct thiocholine histochemical staining. Anesthetized Hartley guinea pigs were killed, and the tympanic bullae were removed intact, fixed in 4% paraformaldehyde, and then stained whole. Following staining, the tympanic membrane was dissected from each bulla and whole-mounted for light microscopy. Numerous acetylcholinesterase-positive fibers were observed on the tympanic membrane. Some fibers appeared to be vessel associated, although the majority did not. This suggests that these fibers may act on the mucosa or vasculature of the tympanic membrane and contribute to the pathogenesis of middle ear effusion.     

Acute otitis media develops in the rat after intranasal challenge of Streptococcus pneumoniae

OBJECTIVES/HYPOTHESIS: The rat is a frequently used animal model for middle ear research. To date, acute otitis media (AOM) has been evoked after instillation of bacteria directly into the middle ear cavity or after traumatizing the tympanic membrane. The purpose of the study was to examine whether, with an intact tympanic membrane and middle ear cavity, intranasally deposited bacteria cause AOM and how tympanic membrane stimulation influences this procedure. STUDY DESIGN: In vivo, murine model. METHODS: In a rat model, Streptococcus pneumoniae, type 3, was intranasally inoculated for 5 consecutive days. The tympanic membrane was treated with saline or with compound 48/80 or was left untreated. The development of AOM was evaluated by otomicroscopy, light microscopy, and middle ear culture. RESULTS: Ninety percent of the ears developed AOM. However, when the tympanic membranes were treated with saline or compound 48/80, only 40% and 57%, respectively, developed AOM. In all, 23 of 40 ears developed AOM and 20 ears showed growth of bacteria. CONCLUSION: Repeated intranasal deposition of S. pneumoniae, type 3, causes AOM in the rat. The development of AOM can be influenced by tympanic membrane stimulation.     

The effects of anesthesia of the tympanic membrane on eustachian tube function

In our previous histological studies of the tympanic membrane, we reported the presence of encapsulated nerve corpuscles that are capable of detecting middle ear pressure. Based on these findings, the relation between sensory receptors in the tympanic membrane and tubal function was examined in a clinical study. Tubal function was tested during Valsalva maneuvers and its active equilibration. Function was recorded as a change of the static compliance of the tympanic membrane on an otoadmittance meter. To paralyze the sensory receptors in the tympanic membrane, iontophoresis was used to induce anesthesia of the drum. Forty ears of 20 subjects were tested. All ears were able to equalize positive middle ear pressure without or with a single swallowing. After anesthesia, 13 ears needed more than two swallows and 4 ears failed to equalize middle ear pressure in spite of repeated swallowings. As eustachian tube function changed following anesthesia of the tympanic membranes, a neural connection between sensory receptors in the tympanic membrane and tubal muscles is suggested.     

The effects of anesthesia of the tympanic membrane on eustachian tube function

Summary In our previous histological studies of the tympanic membrane, we reported the presence of encapsulated nerve corpuscles that are capable of detecting middle ear pressure. Based on these findings, the relation between sensory receptors in the tympanic membrane and tubal function was examined in a clinical study. Tubal function was tested during Valsalva maneuvers and its active equilibration. Function was recorded as a change of the static compliance of the tympanic membrane on an otoadmittance meter. To paralyze the sensory receptors in the tympanic membrane, iontophoresis was used to induce anesthesia of the drum. Forty ears of 20 subjects were tested. All ears were able to equalize positive middle ear pressure without or with a single swallowing. After anesthesia, 13 ears needed more than two swallows and 4 ears failed to equalize middle ear pressure in spite of repeated swallowings. As eustachian tube function changed following anesthesia of the tympanic membranes, a neural connection between sensory receptors in the tympanic membrane and tubual muscles is suggested.     

Tympanometry

The basic principles essential for interpreting two-component, multiple frequency tympanograms first are reviewed. These principles then are applied to an analysis of tympanometric shape (conductance, susceptance, and admittance tympanograms) as a function of probe frequency in subjects with normal middle ear transmission systems. The final section presents tympanometric data from patients with confirmed middle ear pathologies that produce an increase in resonant frequency (e.g., middle ear effusion, otosclerosis, ossicular adhesions, and tympanic membrane retraction) or a decrease in resonant frequency (e.g., otitis externa, serous otitis media, tympanic membrane pathology, and ossicular discontinuity). The advantages and disadvantages of a particular probe frequency and/or admittance component are illustrated with individual cases. The cases further demonstrate that the same tympanometric pattern can be recorded from ears with different pathologies (e.g., tympanic membrane perforation with cholesteatoma, tympanic membrane retraction, ossicular adhesions, and middle ear effusion), and conversely, that the same pathology can result in different tympanometric shapes (e.g., tympanic membrane perforation, middle ear effusion, and otosclerosis). Caution, therefore, must be exercised in ascribing a tympanometric abnormality to a specific middle ear lesion.     

Comparison of tympanometry and otomicroscopy during healing of otitis media

One hundred ears in 50 children with acute otitis media during healing were examined with tympanometry and the objective measures were compared with the subjective evaluation of otomicroscopy by four otolaryngologists independently. Tympanometric findings could more often correctly suggest reduced tympanic membrane mobility than did otomicroscopy, but both methods gave an equally good indication of middle ear effusion. However, otomicroscopy was necessary when evaluating the colour and the appearance of the tympanic membrane and revealed middle ear effusion in a few cases with 'normal' tympanometry. As a rule: normal tympanometry (Jerger type A) was closely correlated with a normal tympanic membrane and a normal middle ear without effusion; pathological tympanometry (Jerger type B) was accompanied by middle ear effusion and needed follow-up; ears with tympanometric pressure more negative than -150 mmH2O but more positive than a flat curve needed otomicroscopy to identify middle ear effusion.     

Cartilage interposition in ossiculoplasty with hydroxylapatite prostheses: a histopathologic study in the guinea pig

In this experimental animal study, a cartilage disk was interposed between a synthetic middle ear prosthesis and the tympanic membrane in guinea pigs to investigate its effect on the extrusion process of the implant. Two groups of guinea pigs were studied. One group consisted of animals in which the prosthesis was directly in contact with the tympanic membrane, and the other group consisted of animals in which a cartilage disk had been inserted between the head of the prosthesis and the tympanic membrane. Before histologic processing, in situ inspection was performed with an operating microscope. After fixation and embedding, light microscopic and transmission electron microscopic examination were performed. We studied the histopathologic aspects of the tympanic membrane with regard to the protrusion and extrusion processes of the middle ear implant. In this experimental model, protrusion and extrusion of a hydroxylapatite middle ear prosthesis was greatly reduced by interposition of a cartilage disk. Further clinical evaluation of these experimental results is needed in the human middle ear.     

Effect of artificial airway on ear complications from hyperbaric oxygen

Hyperbaric oxygen treatment is associated with an increased risk of barotrauma to the tympanic membrane and middle ear. An artificial airway may compromise normal eustachian tube function and equilibration of middle ear pressures. This retrospective study was designed to evaluate the risk of middle ear complications in 267 patients receiving hyperbaric oxygen (HBO) therapy and to compare those with and without artificial airways. Charts of all patients were reviewed for middle ear and tympanic membrane complications and myringotomy tube placement. Eighteen of the 267 patients had artificial airways. Seventeen (94%) of these 18 patients developed middle ear or tympanic membrane complications, and 11 (61%) required tympanostomy tubes for pain, hemo-tympanum, or serous otitis. In contrast, 114 (45.8%) of the 249 patients without airways developed ear complications, and 53 (21.3%) required tympanostomy tubes. These results suggest that patients with an artificial airway who are receiving HBO therapy are at greater risk for developing tympanic membrane and middle ear complications than nonintubated patients. Similarly, patients with artificial airways receiving HBO frequently require placement of tympanostomy tubes.     

The middle ear of gekkonoid lizards: interspecific variation of structure in relation to body size and to auditory sensitivity

Wishing to assess the effects of the dimensions of the middle ear on the auditory sensitivity of gekkonoid lizards, we measured middle ear components in preserved geckos, which in life had yielded 'cochlear microphonics' audiograms. We examined two to seven specimens of 14 species. The measures of middle ear elements varied relative to head or body length similarly within species and among species. The areas of the external ear opening, tympanic membrane, and columellar footplate, and the ratio between the last two ('hydraulic lever'), were correlated with animal length. The hydraulic and mechanical (extracolumellar) lever ratios appeared to complement each other, the former being emphasized in large animals, the latter in small animals. The apparent auditory sensitivity correlated with the sizes of the animal, head and external ear opening, and negatively (insignificantly) correlated with the mechanical lever ratio. The correlation of sensitivity with the hydraulic lever was insignificant, perhaps due to a 'tympanic membrane lever' (catenary effect). The most sensitive frequency negatively correlated with the area of the external ear opening, the area of the tympanic membrane, and with the level of greatest sensitivity. It was positively correlated with the relative length of the cartilaginous portion of the ossicular chain. However, the number of hair cells in the basilar papilla, too, is known to correlate with animal size. Moreover, the least sensitive species were not only the smallest species, they were also the species known to lack a zone of unidirectional hair cells in the basilar papilla. Hence the apparent sensitivity hypothetically depends on both middle ear dimensions and summation of inner ear output. This hypothesis requires verification by other methods.     

Congenital Cholesteatomas in the Tympanic Membrane

The etiology of congenital middle ear (ME) cholesteatomas is unclear. One etiologic possibility of ME cholesteatoma may be progression of a congenital tympanic membrane (TM) cholesteatoma. We recently have encountered three cases of congenital tympanic membrane cholesteatoma. Each child, ages 1, 3, and 14 years, presented with cholesteatoma of the tympanic membrane extending into the middle ear. These children have not had previous otologic surgery including myringotomy, nor had they had repeated middle ear infections, perforation, or trauma. Neither the 3-year-old nor 14-year-old child complained of hearing loss. Audiograms demonstrated only a mild conductive loss. Each child underwent excision with tympanoplasty. Although the middle ear component of the cholesteatoma was always more extensive than the pearl seen, the point of attachment was the TM and not the middle ear. This demonstrates one possible source for congenital cholesteatomas.     

Langzeitbeobachtungen chronischseröser Otitis media nach experimentellem Tubenverschluß bei Katzen

Summary In order to induce a serous otitis media in cats, the pharyngeal opening of the Eustachian tube was cauterized and obstructed on one side only through transpalatal approach; the other side remaind intact and served as control. On tympanic membrane examination and puncture 11 months later, there was fluid in the middle ear in three ears, no fluid in two ears, a tympanic membrane perforation in one ear and a red tympanic membrane in one ear. The middle ear was then ventilated through a plastic tube in two ears with and without fluid respectively. In all other ears, no tube was inserted. After another 7 months, the animals were intravitally perfused, and the middle ear mucosa biopsyed. The histological results of the light and electron microscopy showed chronic changes of the middle ear mucosa following experimental tubal obstruction.     

中耳机械模型的建立及听骨赝复物传音特性的研究

目的探讨对人工听骨赝复物传音功能进行评价的客观方法，以及钛金属人工听骨赝复物不同质量和不同顶盘面积在中耳机械模型中对传音功能的影响。方法用两块圆形的弹性膜分别代替鼓膜和前庭窗，两膜之间放置人工听骨，在人工外耳道侧给予纯音刺激，同时记录其声强，在前庭窗膜处用激光测振仪测量前庭窗膜的振动速度，通过比较振动速度的大小来比较人工听骨的传音特性；将质量不同和面积不同的2组钛人工听骨分别安放于中耳机械模型中测量其传音特性。结果模型感觉阈曲线和正常人听阈曲线对比，两者走势基本相同。钛听骨顶盘面积较小的听骨在1500-4000Hz其传音特性优于顶盘面积较大的听骨；质量小的听骨在高频区传音好，质量大的听骨在低频区传音比较好，但总体上质量小的听骨传音特性较好。结论中耳机械模型是检验人工听骨传音特性并进行人工听骨赝复物客观评价的理想工具之一；钛人工听骨的质量和顶盘的面积对其传音特性均有影响，在设计人工听骨时或手术要同时考虑到质量和顶盘面积对传音的影响。     

Intratympanic membrane congenital cholesteatoma

We present two, different-sized, intratympanic membrane congenital cholesteatomas. Congenital cholesteatoma within the tympanic membrane is extremely rare. One of our cases was a small pearl centered on the umbo and the other involved the whole of the tympanic membrane. In both cases the cholesteatomas involved only the outer epidermic layer of the tympanic membrane without extension into the fibrous layer. The intratympanic membrane cholesteatomas may eventually violate the middle ear space. We believe that early diagnosis and removal of intratympanic membrane cholesteatomas is necessary to avoid complications in the middle ear space.     

Experimental study of vibration analysis in middle ear models by holographic interferometry. Effects of the cross-sectioned area of aditus on the vibration of tympanic membrane

To aid in the establishment of optimum conditions for postoperative function of the tympanic membrane, a model of the middle ear was experimentally prepared, the cross-sectioned area of aditus ad antrum was altered and the effects on the tympanic membrane vibrational characteristics were observed using the holographic interference method. The following results were obtained. 1) At the low frequencies below 2 kHz, the vibration mode of tympanic membrane was concentric on the whole, but the vibration pattern became fractionated at 4 kHz and above. The frequency of onset of the fractionated vibration pattern was changed only by the conditions of the membrane itself and was not affected much by the sound pressure, the volume of the middle ear cavity and the cross-sectioned area of aditus ad antrum. 2) There were resonance and anti-resonance points in the tympanic vibration pattern. These resonance and anti-resonance frequencies became higher as the diameter of aditus increased until eventually a constant value was reached. At diameters in excess of this constant value, the resonance frequency tended to fall and the anti-resonance frequency tended to rise. 3) The tympanic vibration in the middle ear cavity was not influenced very much by the diameter of aditus at 250Hz. Vibration decreased when aditus was blocked at 500Hz and the opening diameter had a major influence at 1kHz. Vibration was maximum at a diameter of about 2mm and a minimum when aditus was blocked. At 2 to 3kHz, the effects on vibration increased when aditus was blocked. 4) When aditus ad antrum was blocked, the vibration frequency characteristics of tympanic membrane deteriorated at under 1kHz and improved at 2 to 3kHz. When a comparison was made between the case with opened aditus, (which was considered to be equivalent to the closed method of tympano-plasty), and the case with closed aditus, (considered to be equivalent to the open method), the vibration frequency characteristics of the tympanic membrane improved in the low sound region up to 2kHz when the diameter was 4mm.