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At least 91 records · Page 5Linked to original sources
PubMed1992

[The mechanics and function of the middle ear. Part 1: The ossicular chain and middle ear muscles].

The revelation of a sophisticated micro-mechanism within the ossicular chain--the gliding of the joints results in a characteristic change of the ossicular movement--extended our conception of the function of the ossicular chain. Contrary to our former ideas of the transmission of sound during hearing, the ossicles do not rotate around an axis, which runs through the center of mass of the malleus and anvil. The imaginary rotational axis is located outside the ossicles, resulting in a more piston-like vibration of the complete chain. The ossicular joints are rigid. This acoustic function of the ossicular chain must rigorously be separated from its behaviour at changes of static, ambient air pressure. The middle ear, working as a sensitive pressure receptor also reacts to these pressure changes with comparatively huge displacements of the drum membrane (visible in pneumatic otoscopy). Only now the malleus rotates around its axial ligaments. These movements cause a gliding motion in the malleus-incus joint, which results in a predominant up- and downward movement of the anvil; the incudo-stapedial joint glides, too, and the stapes (and the inner ear) are decoupled. This micro-mechanism explains several anatomical features of the middle ear construction, as there are the vertical alignment of the incudo-stapedial joint, the suspension of the anvil, the design of the malleus joint, etc. It also accounts for the peculiar anatomical arrangement of the middle ear muscles. Their function can be interpreted as preserving the intact cartilage of the ossicular joints.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1980

[The influence of tympanoplasty and middle ear aeration on tubal function in chronic middle ear disease (author's transl)].

Eustachian tube dysfunction could be demonstrated in 2/3 of our patients with chronic middle ear diseases (inclusive of central perforations, tympanic membrane retractions, adhesive otitis and cholesteatoma). In 68 patients with grommet tubes placed at surgery, Eustachian tube function was followed over a period of three years by using a pressure-equalization test. Four months after surgery, only a few of the patients with impaired tube function showed any improvement of function. Prolonged ventilation through the grommet was not found to have any significant effect on tubal function. In patients with impaired Eustachian tube function--especially when the tube cannot be opened by forced pressurizations--the development of negative middle ear pressures must be expected if existing tympanic membrane perforations are closed. This is considered to be one of the important causes for the high rate of failure following tympanoplasties. Reducing this rate can possibly be achieved by the use of grommet tubes at time of surgery, thus securing ventilation of the middle ear. In addition, radical mastoidectomy should be considered in comparable patients with cholesteatomas.

Eustachian Tube↗
PubMed1999

[Efficacy of middle ear surgery for patients with hearing aids and middle ear disease].

Of 356 cases that underwent middle ear surgery for hearing improvement, 30 (8.4%) with air conduction hearing aids and middle ear disease were evaluated pre- and postoperatively. All surgeries were performed by the same surgeon. Diagnoses included 22 chronic otitis media, 5 chronic otitis media with cholesteatoma, 1 otosclerosis and 2 ossicular anomaly. Chief complaints at the first visit to Fukui Medical University Hospital were otorrhea (17 cases), hard of hearing (28 cases), dizziness (2 cases) and tinnitus (2 cases). Nineteen patients underwent surgery on both ears and eleven on one ear including five ears that showed better hearing preoperatively. Surgical procedures were tympanoplasty type I (15 cases), modified type III (8 cases), modified type IV (3 cases), stapedotomy (2 cases) and implantable hearing device (2 cases). After surgery, 16 patients (group 1) did not need hearing aids, while 14 (group 2) still needed hearing aids. Preoperative hearing was 64.1dB (n = 30) on average and average hearing one year after surgery in group 1 (35.4 +/- 14.1dB) was significantly better than in group 2 (58.1 +/- 18.4dB). After surgery, otorrhea stopped in all cases (100%), subjective hearing loss improved in 82% of the patients, vertigo improved in 100% and tinnitus improved in 50%. These results emphasize the benefits of surgical therapy, and the reasons why it should be recommended to patients with hearing aids and middle ear disease, such as to improve hearing disorders, to stop otorrhea and to prevent progressive sensorineural hearing loss.

Adolescent↗
PubMed1976

Symposium: Congenital anomalies of the middle ear. II. Vascular anomalies of the middle ear.

Of all the abnormal situations that one encounters in performing a tympanotomy, probably the last one to be thought of is vascular anomalies, and yet, potentially, this is one of the most hazardous of anomalous problems with which we have to deal. Most of the anomalies which have been reported concern the persistent stapedial artery. This artery arises from the stump of the second aortic arch (stapedio-hyoid artery), it traverses the developing stapes bone, leaving behind a monument to its existence - the obturator foramen of the stapes. The artery exits from the middle ear along the horizontal portion of the facial nerve, traversing this area for a variable distance and then usually divides into an intra-cranial branch and a sphenoidal branch. The stapedial artery in its development before its regression, gives rise to the anlage of many important cranial arteries. These vessels are usually anastomosed with and distributed by the branches of the internal maxillary artery and the ophthalmic artery. The hyoid artery is represented in the adult by the carotico tympanic artery. Anomalies involving the internal carotid artery are much more rare. The anomalies that have thus far been reported are: 1. Absence of the internal carotids. 2. Aneurysms. 3. Unusual courses. Venous anomalies are generally uncommon and are usually represented by an abnormally placed jugular bulb which can simulate a glomus jugulari tumor.

Aneurysm↗
PubMedDate not supplied

Measurements of middle-ear function in the Mongolian gerbil, a specialized mammalian ear.

The middle ear of the Mongolian gerbil is thought to be specialized so that it can hear the 3,000-Hz and lower sounds produced by approaching predators. Evidence in the literature suggests several specializations: (1) an effect of the large middle-ear air spaces in the gerbil is to increase the sensitivity of this ear to sounds of 3, 000 Hz and lower in frequency; (2) the combined action of the middle-ear cavity and the significant pars flaccida of the tympanic membrane in the gerbil ear reduces the sensitivity to sounds of frequencies below 500 Hz. This paper describes anatomical and functional measurements of stapes motion and suggests that the stiffness of the gerbil ossicular system also acts to reduce sensitivity to low-frequency sounds. The primary conclusion is that the frequency dependence of the gerbil middle ear is the result of the interaction of multiple factors, thereby complicating the relationship between single structural specializations and overall function.

Acoustic Stimulation↗
PubMed1996

Pathogenesis of middle ear adhesions.

Middle ear adhesions are well-known to the ear surgeon, although data on etiology, pathogenesis, and significance are lacking in current literature. This study on experimental acute otitis media presents histopathological data on these aspects. Pneumococci were inoculated in the right middle ear bulla of 25 rats; the left ear served as control. At days 4, 8, 16, 90, and 180, respectively, 5 rats were decapitated, and the bullae were removed, opened, and stained with periodic acid-Schiff (PAS)/alcian blue. The entire middle ear mucosae were dissected from the bone, embedded as whole mounts in colophonium chambers, and examined by light microscopy. Representative parts of the mucosae were sectioned and examined in the same way. All inoculated ears from day 8 and later (20 in total), contained mucosal adhesions of various sizes, shapes, and locations. None were found in control ears. The site of predilection for the development of adhesions was the hypotympanum, followed by the anterior epitympanum, the attic, the drum, the interossicular spaces, and the tubal orifice. Based on present histopathological findings, we conclude that the middle ear adhesion is a pathological phenomenon caused by infection, and we propose a six-stage hypothesis of pathogenesis: 1. Localized epithelial rupture; 2. Prolapse of subepithelial tissue; 3. Epithelialization of the prolapse; resulting in a polypous/fold-like prominence; 4. Growth and elongation of the prominence; 5. Fusion of the end/tip of the prominence with another part of the mucosa; 6. Formation of an adhesion.

Acute Disease↗
PubMed2006

Middle ear adenoma.

Middle ear adenoma is a benign tumor of the middle ear that can have exocrine (mucinous) and/or neuroendocrine differentiation. Early authors described a separate tumor with predominantly neuroendocrine differentiation as a middle ear carcinoid tumor, but these are now known to be the same tumor. We review the literature of this tumor, including the clinical presentation, gross pathology, histopathology, immunohistochemistry, differential diagnosis, and prognosis.

Adenoma↗
PubMed2004

Epidermal growth factor expression in middle ear cholesteatoma.

Middle ear cholesteatoma is destructive to auditory ossicles and temporal bone, and treatment usually requires surgical removal of all epithelial content. Epidermal growth factor (EGF) can stimulate the growth and differentiation of a variety of mammalian cells, including epithelial cells. Our study used the avidin-biotin complex technique to evaluate the expression of EGF in 40 cases of middle ear cholesteatoma (active cholesteatoma, 31 cases; inactive cholesteatoma, 9 cases) and 34 normal postauricular skin samples. In middle ear cholesteatoma, EGF was expressed in squamous epithelium in 21 cases (53%), fibroblasts in two cases (5%), and cholesteatoma endothelium in two cases (5%). In normal postauricular skin, EGF was expressed in squamous epithelium in 14 samples (41%), fibroblasts in one sample (3%), and endothelium in none. No statistical difference in EGF expression was found between cholesteatoma and normal postauricular skin samples. These results show that the distribution of EGF in middle ear cholesteatoma is not deranged and that the progression of cholesteatoma might be induced by the release of factors from the cholesteatoma matrix via autocrine stimulation, or by inflammatory cells of the subepithelial tissue through paracrine stimulation, or in both of these ways.

Adult↗
PubMed1986

Studies on the mechanics of the normal human middle ear.

The middle ear was studied in temporal bone preparations using a laser-Doppler interferometer. For measurements at a sound level of 80 dB SPL this method proved to be very reliable, as was shown by good reproducibility of results in experiments over more than 6 hours. The vibrations of the tympanic membrane and stapes footplate were studied from 200 Hz to 10 KHz and the results demonstrate a piston-like movement of the stapes footplate up to 120 dB SPL. The damping effect of the normal ear is located mainly at the footplate/cochlea level and the middle ear cavity per se does not contribute significantly to the stiffness of the middle ear system.

Acoustic Stimulation↗
PubMedDate not supplied

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.

Animals↗
PubMedDate not supplied

Household smoking exposure--association with middle ear effusions.

Middle ear effusions are associated with hearing impairments which may result in abnormalities or lags in children's hearing, speech, and cognition. Treatment rather than prevention of this problem has previously been emphasized in the medical literature. While the risks of passive smoking on various aspects of health are now becoming accepted, little is known about the effect of smoke exposure on the middle ears of children. We evaluated the association between middle ear effusions and household smoke exposure in children seen in an outpatient office. A dose-response relationship was found between increasing household smoke exposure and the prevalence of middle ear effusions as indicated by abnormal tympanograms. An attempt to minimize smoke exposure via patient education may be one of the few means health care professionals have to effect primary prevention of this potentially morbid disease.

Acoustic Impedance Tests↗
PubMed1982

Adenocarcinoma and adenoma of the middle ear.

Primary middle ear glandular tumors of the adenocarcinoma and adenoma types are rare. The terminology used in describing them is quite varied. Some investigators presume that a distinct recognizable group of these tumors are benign, but because of the rarity of the lesions, such conclusions have been difficult to verify. We review the literature of these lesions and report 11 additional cases. The course was documented in 25 cases in the literature; 20 of these were reported to be benign over periods of follow-up from 1 month to 10 years, and 5 were fatal. Among our patients, 5 had a benign course, 3 died of causes related to the tumor, and 3 had persistence of their lesion and substantial consequent morbidity. We emphasize the slow growth and elusive nature of these lesions. Histologic evidence of mitoses, roentgenologic evidence of bony destruction, and cranial nerve involvement were factors consistent with a poor prognosis. The origin of these tumors may vary. A similarity to paragangliomas is noted. The ultimate course of these tumors cannot always be predicted from the histologic appearance. Early surgical removal appears to be the most successful therapy. Three of the 4 types of glandular tumors of the external ear canal described by Wetli, et al, can be found in the middle ear: adenoma, adenocarcinoma, and adenoid cystic carcinoma. In addition, several other types of glandular lesions can occur in the middle ear--the "choristomas," mucoepidermoid carcinomas, and what we believe to be a variant of paragangliomas. The adenoid cystic tumors are well described in the literature and will not be discussed here. We reviewed cases of the adenoma and adenocarcinoma types, some of which bore a resemblance to the paragangliomas.

Adenocarcinoma↗
PubMed1993

[A case of middle ear adenoma].

Middle ear adenomas are rare and difficult to diagnose. Recent histological studies suggest the presence of a distinct disease entity known as a middle ear adenoma. A 16-year-old boy with a middle ear tumor was treated by partial temporal bone resection, and the tumor was removed by a combined method using the middle cranial fossa and infratemporal fossa approaches. Histological and immunohistochemical studies on this tumor showed the findings of a benign adenoma. Left facial palsy was noted postoperatively, but it subsequently recovered almost completely.

Adenoma↗
PubMed1992

[Middle ear inflammation and fluid accumulation in the middle ear in Icelandic children].

The bacterial flora was examined in 108 Icelandic children treated for middle ear inflammations during the period, 1986-1989. Among children with acute otitis media, growth of H. influenzae was obtained in pure cultures in 54 per cent of cases. Where inflammation had caused tympanic membrane rupture, both H. influenzae and S. pneumoniae were cultured in 58 per cent of the samples. In the group with persistent seromucous secretion in the middle ear, 60.5 per cent of the samples were abacterial. S. aureus was the species most commonly isolated in samples from children with chronic discharge. The results suggest H. influenzae to be more common in acute otitis media in Iceland than elsewhere.

Child, Preschool↗
PubMed2001

[Feasibility of inner ear gene transfer after middle ear administration of an adenovirus vector].

BACKGROUND: Several groups demonstrated in animal experiments that gene transfer is a feasible tool for inner ear intervention. Various approaches for inoculation of vectors have been successfully used for inner ear gene therapy. One possible way to reduce the risk of hearing loss following the opening of the cochlea for application of the vector into the perilymphatic space is to deliver vectors through the round window. This study was designed to determine whether middle ear application of an adenoviral vector is a feasible approach to inoculate vectors and lead to transduction of cells in the inner ear. METHODS: A unilateral middle ear application of an adenoviral vector was performed in 4 guinea pigs directly on the round window membrane (RWM) and in 4 additional animals by placing a cotton patch soaked with the vector solution on the RWM. The expression of a reporter gene (lacZ) was used to localize vector-transduced cells. RESULTS: Only one out of 8 animals showed cochlear expression of the reporter gene, whereas all 8 animals showed strong lacZ expression in the middle ear mucosa, in the RWM and in the mucosa surrounding the stapes. CONCLUSION: Our results indicate that the RWM presents a close barrier, almost completely preventing the adenovirus to diffuse into the perilymphatic space. Therefore middle ear application of an adenoviral vector cannot be used to induce inner ear gene transfer. However, middle ear application of a viral vector may be useful for developing treatment for diseases of the middle ear mucosa.

Adenoviruses, Human↗
PubMed1988

Serous otitis media (S.O.M.). A bacteriological study of the ear canal and the middle ear.

A bacteriological study of the middle-ear effusions and the ear canals in children with chronic serous otitis media (S.O.M.) was performed. Sixty-eight children (127 ears) were investigated. From this study it appeared that cleansing of the ear canal with 0.5% chlorhexidine in 70% ethanol for 30 s is partially effective; micro-organisms (diptheroids, Staphylococcus epidermidis) could still be isolated in 29%. Cleansing of the ear canal decreases the incidence of middle-ear fluid contamination by non-pathogenic ear canal organisms (diptheroids, Staphylococcus epidermidis, Aerococcus), but after cleansing, 'non-pathogenic' micro-organisms could still be isolated in 33% of the effusions (diptheroids, Staphylococcus epidermidis). From 12% of the middle-ear effusions pathogenic micro-organisms (Hemophilus influenzae, Staphylococcus pneumoniae) were isolated; cleansing of the ear canal did not influence this percentage. Anaerobics were not isolated from the middle-ear effusions.

Adolescent↗
PubMed1998

[Physiopathology of inflammation of the middle ear].

The middle ear plays a key role in the transmission of the sound vibrations from the tympanic drum to the inner ear. The author makes a survey of our current understanding of the maintain of air-filled cavities: muco-ciliary clearance, control of water flux across the mucosa, role of the Eustachian tube. Pathophysiology of the middle ear is primarily concerned with the major changes which occur in the middle ear in the course of secretory otitis media. These changes will allow the development of the various forms of chronic otitis media.

Child↗