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Osteomas in the middle ear are extremely rare and are generally solitary and small. We present a case of a 28-year-old female patient with multiple middle ear osteomas which arose from the promontory, epitympanum, and lateral semicircular canal. The osteomas were successfully removed by tympanomastoidectomy. This is the first reported case of a patient with middle ear osteomas arising from multiple sites.
The middle ear structures of eight species of mole in the family Talpidae (Mammalia: Eulipotyphla) were studied under light and electron microscopy. Neurotrichus, Parascalops, and Condylura have a simple middle ear cavity with a loose ectotympanic bone, ossicles of a "microtype" morphology, and they retain a small tensor tympani muscle. These characteristics are ancestral for talpid moles. Talpa, Scalopus, Scapanus, and Parascaptor species, on the other hand, have a looser articulation between malleus and ectotympanic bone and a reduced or absent orbicular apophysis. These species lack a tensor tympani muscle, possess complete bullae, and extensions of the middle ear cavity pneumatize the surrounding basicranial bones. The two middle ear cavities communicate in Talpa, Scapanus, and Parascaptor species. Parascaptor has a hypertrophied malleus, a feature shared with Scaptochirus but not found in any other talpid genus. Differences in middle ear morphology within members of the Talpidae are correlated with lifestyle. The species with middle ears closer to the ancestral type spend more time above ground, where they will be exposed to high-frequency sound: their middle ears appear suited for transmission of high frequencies. The species with derived middle ear morphologies are more exclusively subterranean. Some of the derived features of their middle ears potentially improve low-frequency hearing, while others may reduce the transmission of bone-conducted noise. By contrast, the unusual middle ear apparatus of Parascaptor, which exhibits striking similarities to that of golden moles, probably augments seismic sensitivity by inertial bone conduction.
Negative pressure in the middle ear has been identified as an important factor in the pathogenesis of middle ear disease. Unfortunately, to date, the physiological mechanisms that control middle ear pressure are poorly understood. Recent interest has focused on the possible role of carotid body-like tissue in the middle ear (the glomus tympanicum) as a chemoreceptor for changes in the gas composition of the middle ear. From the few anatomical studies of normal glomus tissue in the temporal bone it would seem that glomus bodies may not be consistently present in the middle ear. In this study, glomus bodies were sought in histological preparations of the promontory mucosa and tympanic plexus. It was found that the glomus tympanicum is only occasionally present in the middle ear mucosa, and thus a chemoreceptor role specific to the middle ear is unlikely.
The development of the murine middle ear was monitored both qualitatively and morphometrically by scanning electron microscopy from the 19th gestational day to the adult stage. At birth, the middle ear was less well developed than the inner ear. The tympanic membrane (TM) was obscured by occlusion of the external auditory canal. Ciliated cells and secretory granules were present in the middle ear epithelium already 5 days after birth (DAB). Keratin debris was discerned on the external layer of the TM 9 DAB. By 12 DAB, mesenchymal tissue had resorbed from the middle ear cavity, except around the upper part of the ossicles. The middle ear was immature at birth but developed rapidly until 12 DAB. When compared with the avian middle ear the mouse middle ear was basically similar to that of humans, although in the human the stapedial artery is vestigial whereas in the mouse it persists as an important vessel. In man, there is no orbicular apophysis and no gonial of the malleus. The hypotympanum of the human middle ear is less developed than that of the murine middle ear. The mouse external auditory canal matures postnatally until 12 DAB, while in humans its development is complete at birth.
Carcinoma of the middle ear is a rare disease. We report about a 65-year-old man in which case it is assumed that a transtubal implantation metastasis of an adenocarcinoma had settled in the middle ear. Regular irrigation of the operated nose and unnoticed carcinoma recurrence were main assumptions for intracanicular metastasis. With experiments on dead and alive we could show that irrigation fluid intrudes through the tube into the middle ear. Finally the problem of growth of carcinoma cells on intact epithelial surfaces is critically discussed.
Biopsy specimens from middle ear mucosa of patients with secretory (SOM) and chronic (COM) otitis media as well as specimens of adenoid and tonsil tissue were studied for mast cells. Effusion fluid, nasopharyngeal secretion and supernatant of crushed adenoid tissue were analyzed for histamine with a radioenzymatic method. Astra blue (AB) safranine stained highly significantly more mast cells than did toluidine blue. Mast cell counts in SOM and COM were similar. There were significantly more mast cells in adenoid subepithelial tissue than in middle ear mucosal subepithelial layer. For epithelium the counts were within the same range in adenoids and middle ear mucosa. Histamine concentrations were significantly higher than plasma levels for SOM fluid and nasopharyngeal secretion. Crushed adenoid tissue showed values over 100 times higher than the histamine level in the secretion.
A safety study regarding the potential ototoxicity of 1.9% hyaluronan was performed in 20 rats. In all animals the middle ear was completely filled with hyaluronan three times at 2-day intervals between the administrations. Inner ear function was evaluated by computerized auditory brainstem response (ABR) measurements. ABR recordings were performed prior to exposure, after myringotomy (but prior to administration of hyaluronan), 5 days after the last administration (n = 15; these animals were then sacrificed for analysis of the middle ear), one month and 3 months later (n = 5). The hearing thresholds were improved in animals 5 days after the last administration of hyaluronan at 6-8 kHz, whereas the hearing thresholds were impaired at 12 and 20 kHz. After one month, ABR thresholds were even better than precontrol levels at 2, 4 and 6 kHz, whereas at all other frequencies the ABR threshold was normal. Three months after hyaluronan exposure, all ABR thresholds were normal, but viscous material was present in the middle ear in 3 of 5 animals. It is concluded that hyaluronan causes reversible changes in inner ear function but lacks ototoxic adverse effects.
The middle ear is a balanced gas pocket which loses and gains gas constantly. This balance depends on the continuous interchange of gases from the atmosphere, through the eustachian tube and the circulating blood by diffusion. The relative contribution of each of these two sources can be determined by measuring the gas composition of the middle ear (ME). Because of the small quantity of gas in the ME, adequate sampling and accurate measurement of its composition are extremely difficult. An on-line system for middle ear gas composition measurements is described. The measuring instrument is mass spectrometer. ME gas samples are withdrawn by diffusion, and therefore are very small. Sampling and measurements are performed in a continuous mode.
The gas composition of the middle ear differs from that of air, and resembles the gas composition of mixed venous blood. This observation suggests the existence of a bi-directional route for gas diffusion between the middle ear and blood. In an attempt to demonstrate this route in a direct way, we tracheotomized guinea pigs in such a way that they breathed freon-22 directly into the distal part of their tracheostomy. The proximal part of the trachea was sealed so that air by-passed the oropharynx and nasopharynx, thus preventing freon-22 from making contact with the eustachian tube orifice. At the same time middle ear gases were monitored with a mass spectrometer, through a measuring probe which was inserted into a hole in the bulla. The appearance of freon-22 in all middle ears--after 8 min on the average--demonstrated direct gas diffusion from the blood into the middle ear, since freon-22 could reach the middle ear only from the blood stream, i.e., by diffusion. Differences in gas diffusion rates into and from the middle ear may therefore play a role in regulating middle ear gas economy, and therefore in middle ear pressure.
AIM: To analyse the presenting symptoms of patients with nasopharyngeal carcinoma seen in Auckland, New Zealand, with emphasis on the significance of otological symptoms. METHOD: The records of 85 patients with nasopharyngeal carcinoma seen in the department between 1980-93 were reviewed. RESULTS: Twenty eight of patients were Pacific Island Polynesian, 21 caucasian, and 18 Chinese. The youngest patient was 11 years old. The most prominent symptoms were neck mass (53), deafness/otalgia (45), nasal obstruction (35) and epistaxis (30). The ear symptoms, representing middle ear effusion were evident for more than 9 months, on average, before a diagnosis was made. Most patients presented with multiple symptoms: 95% of patients had one or more of the above four cardinal symptoms. Only two patients presented with middle ear effusion alone: 95 of the patients with middle ear effusion had another, accompanying, cardinal symptom. Nineteen patients had cranial nerve involvement. CONCLUSIONS: Neck mass, deafness/otalgia, progressive nasal obstruction and epistaxis are the cardinal symptoms of nasopharyngeal carcinoma. A persisting middle ear effusion in people over 10 years of age must be examined for nasopharyngeal carcinoma, if an accompanying cardinal symptom is also present, or develops.
Secretory otitis media, middle ear atelectasis, and retraction type cholesteatomas are the most frequently occurring chronic middle ear diseases; and eustachian tube obstruction and the generation of negative or less than atmospheric middle ear pressure is said to be an essential factor in the pathogenesis of these diseases. It has been found that habitual sniffing causes high degrees of negative middle ear pressure in diseased ears; this finding demonstrates eustachian tube patency rather than obstruction. Ears intubated for chronic secretory otitis media, middle ear atelectasis, and cholesteatoma were examined to identify patent eustachian tubes. More than one third of the patients aspirated a solution into the middle ear with one or more sniffs by aspirating air from their middle ears, demonstrating eustachian tube patency rather than obstruction.
The histopathological changes in a pair of temporal bones from a 69-year-old woman who had secretory otitis media in the left ear and chronic middle ear infection in the right ear are described. Tympanostomy tubes had been placed in her left ear nine times. The perforation at the grommet showed no ingrowth of squamous epithelium; the fine structure of the tympanic membrane was normal. There were a few mucus strands present in the middle ear, which was lined with a one- to three-cell layer epithelium, where only a few secretory cells were found. In the right ear the thick tympanic membrane showed papillary projections of the squamous epithelium extending from the outer epidermal layer deep into the stroma and close to the collagenous layer of lamina propria. A large marginal perforation was present in the posterior quadrant, but there was no ingrowth of squamous epithelium from the canal into the middle ear. From the anterior margin, a concave veil-like sheet of squamous epithelium had grown onto the incus, chorda tympani and the stapes head. Numerous finger-like projections extended from the margin of this epithelium to the stapedial footplate and the epitympanum. The mucous membrane of the bony portion of the Eustachian tube in both ears was normal to the cartilage level, and the defective ventilation was in all likelihood caused by a dysfunction at the pharyngeal end of the Eustachian tube.
Biochemical analysis of middle ear effusions provides indirect evidence of epithelial function, but no direct studies of middle ear epithelial function have been published. This study uses cell culture techniques to study the bioelectric properties of these cells and their response to pharmacologic agents. Middle ear epithelial cells were isolated by protease and DNase digestion and cultured on collagen matrices. A transepithelial potential difference (PD) measured by calomel half cells peaked by day 8 in culture (PD = -8.6 +/- 1.6 mV). Resistance and short-circuit current (ISC) were calculated to be 307 +/- 46 omega/cm2 and 28 +/- 4.1 A/cm2, respectively. At peak PD, cultures were mounted in flux chambers (Ussing), and pharmacologic agents were applied. Amiloride (10(-4) mol/L), an inhibitor of Na transport, decreased ISC by 52.3% +/- 4.9% but had no effect when added basolaterally. Carbachol (10(-4) mol/L), a cholinergic agonist, had no effect when added to the apical bath but increased ISC by 62.9% +/- 12.4% when added basolaterally. Isoproterenol (10(-4) mol/L), a beta-adrenergic agonist, increased ISC by 4.8% +/- 1.8% when added apically but had no effect when added basally. These results indicate that the epithelium lining the middle ear plays a role in regulating the quantity and composition of liquid in the middle ear by ion transport and that cell culture may be useful in studying this phenomenon.
The middle ear apparatus realized a multiplicatory function during the transfer of the vibrational energy, depending on the area ratio of pars tensa of tympanic membrane and of stapes footplate as well as the lever ratio of long arms of manubrium and of incus. These structures exhibit a size increase during the postnatal development, but the sequel on the multiplicatory function in rabbits is unknown. The middle ear structures of 46 rabbits, 1 to 30 d old, were prepared and measured. The area of pars tensa and the levers of malleus and incus increase with age. After the 10th d of life, no statistical significant growth were measurable. But the calculated multiplicatory factor of single animals indicate the end of the development at the 15th postnatal d. In contrast, the cochlear function attains the adult values not till the 26th d of life. It is 10 d longer than the middle ear growth.
The search for a safe, effective treatment for the vertigo associated with Meniere's disease has long been an important topic in otolaryngology. In recent years many groups have begun using intratympanic gentamicin to treat this vertigo. Although reported cure rates are as high as 90%, many questions remain regarding this type of treatment. Current limitations are the necessity for repeated treatments and a lack of clear dosing guidelines. In addition, the gentamicin must be delivered in a manner that allows maximal vestibulotoxic effect without injury to hearing. Until investigators can control the exact amount of medicine that is placed in the ear and have an understanding of the kinetics of gentamicin absorption, adequate dosing guidelines will be difficult to establish, and therapy will continue to rely on empiric data. We describe the use of a fibrin-based sustained-release vehicle, impregnated with gentamicin, injected into the middle ear of chinchillas. This allows for a prolonged effect without repeated dosing. Using this model, we studied the absorption kinetics of gentamicin at time points ranging from 8 hours to 1 week after injection. We used our findings to create a kinetics curve of gentamicin absorption. We discuss the shape and characteristics of this kinetics curve and examine the effects of the fibrin-based sustained-release vehicle and gentamicin on the middle ear. We noted no absorption in the contralateral (untreated ear) or blood. Through better understanding of the actions of gentamicin in this animal model, we hope to facilitate safer use of intratympanic medicines in our patient population and initiate programs for the use of this sustained-release vehicle in human beings.
Middle ear disease is today's primary aural health problem in school-age children. Until recently, pediatric health researchers were aware only of the medical consequences that middle ear disease had no children. Except in a few cases of chronic otitis media, the effects of middle ear disease were considered transitory. However, current research on middle ear disease suggests permanent changes in hearing sensitivity, reduced development of the auditory neural network and developmental delays in speech, language and cognitive skills dependent on hearing. This article presents a review of recent studies on the physical and behavioral aspects of middle ear disease and its sequelae in school children.
Sweep frequency tympanograms compensating for ear canal volume at 200 and -400 daPa were obtained on 106 ears of 53 subjects during four different sessions. Resonance frequencies were obtained and analyzed to determine normative data, resonance differences between the compensation methods, and the interaction effect of running consecutive tympanograms. There were no gender or interaural differences for either compensation method. Although statistically significant, the compensation method by order interaction found between the first and second runs of tympanograms was not clinically significant. Compensation at 200 daPa was recommended when using sweep frequency tympanometry. Mean resonance frequency difference of the two compensation methods was 400 Hz. Large intersubject variability emphasized the need for audiologists to use proper compensation norms when examining middle ear resonance.
The possible effects of gas ventilation via the middle ear mucosa on middle ear pressure changes with N2O inhalation were studied. Sixty-seven ears without otologic problems were selected from among cases undergoing ENT surgery under general anesthesia. Anesthesia was induced by isoflurane or sevoflurane, and inhalation with a gas mixture of 21/min O2 and 31/min N2O was started under controlled respiration via endotracheal tube. Middle ear pressure was measured each minute with tympanometry just before and during N2O inhalation. Changes in pressure were plotted against time on an X-Y plotter, and the rate of middle ear pressure change and pressure change in 10 minutes were calculated. The following results were obtained; 1. In all cases, the middle ear pressure rose with N2O inhalation. However, the same concentration of N2O created different middle ear pressure changes in different individuals varying from 1.6 mmH2O to 107.8 mmH2O per minute. 2. The rate of middle ear pressure elevation tended to be greater in younger subjects, especially in children aged 4 to 7. 3. There was a negative correlation between the middle ear pressure change and pneumatization of the middle ear. 4. Sex, pulmonary function, and the N2O expiratory flow concentration did not contribute to the variability in the rate of the middle ear pressure elevation.