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Biomedical subjects

J Sadé

Publications and source records attributed to J Sadé.

At least 37 records · Page 2Linked to original sources
PubMed1996

The pars flaccida middle ear pressure and mastoid pneumatization index.

The degree of pars flaccida retraction and the levels of mastoid pneumatization were assessed and correlated in 388 adults with intact pars tensa. Poorly pneumatized mastoids were found to be associated with retraction of pars flaccida; the poorer the pneumatization, the deeper the retraction. Well pneumatized mastoids were usually associated with normal position of the pars flaccida. The pars flaccida was previously also shown to retract in face of ME negative pressure--and its degree can be seen to be an index of ME negative pressure. Thus, the correlation of deeper degrees of pars flaccida retractions with mastoid hypopneumatization (and vice versa) lends strength to the studies which show the mastoid pneumatic system to have a function of a passive ME pressure buffer. This observation lends further evidence as to why ears with poorly pneumatized mastoids are a priori at risk to develop complications such as SOM in adults, tympanic membrane retractions and perforations, incus necrosis or retraction pocket cholesteatoma. Ears with a large pneumatic system are hardly at such risk.

Ear Diseases↗
PubMed1995

Middle ear gas composition and middle ear aeration.

Partial pressures of the gases in the middle ears of 14 guinea pigs were measured continuously on-line with a specially designed mass spectrometer. The average values were carbon dioxide 67.55 mm Hg, oxygen 48.91 mm Hg, and nitrogen 596.54 mm Hg. These values confirm earlier measurements and show that the gas composition of the middle ear differs basically from that of air and resembles that of venous blood. These findings are indicative of bilateral diffusion between the middle ear cavity and the blood. We propose that under physiologic as well as under pathologic (ie, atelectatic) conditions, the gas content of the middle ear is also controlled by diffusion. This mechanism fits well with the fluctuating character of atelectatic ears. Thus, a negative middle ear pressure could be secondary to excessive loss of gases through increased and excessive diffusion, although additional mechanisms are probably also involved. A likely contributing factor is poor pneumatization of the mastoid, with consequent absence of a physiologic pressure regulation mechanism by its pneumatic system.

Animals↗
PubMed1995

Relationship between the gas composition of the middle ear and the venous blood at steady state.

Concomitant continuous measurements of the steady-state gas composition of the middle ear and of the venous blood were recorded by mass spectrometry in four guinea pigs. The following mean values were obtained for the partial pressures of middle ear gases; nitrogen + argon, 606.4 mm Hg; oxygen, 46.2 mm Hg; and carbon dioxide, 60.2 mm Hg. The corresponding values for the venous blood were as follows: Nitrogen + argon, 563.4 mm Hg; oxygen, 38.0 mm Hg; and carbon dioxide, 61.4 mm Hg. The similarity of the steady-state gas composition of the middle ear to that of the venous blood suggests that the partial pressures of the gases in the middle ear are controlled by interchange with gases present in the blood.

Animals↗
PubMed1995

Direct demonstration of gas diffusion into the middle ear.

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.

Animals↗
PubMed1994

A comparison of mastoid pneumatization in adults and children with cholesteatoma.

The records of 190 adults who presented over a 10-year period with previously untreated aural cholesteatomas were analyzed with respect to age, mode of presentation at the level of the tympanic membrane, and pneumatization of the mastoid. The findings were compared with those obtained in an earlier study of 109 children (aged 13 years and younger) seen over the same period of time. Two main types of cholesteatomas were found in both adults and children, most of them (82.3%) associated with sclerotic or diploic mastoids (i.e., poorly pneumatized mastoids) and the rest (17.3%) with pneumatized mastoids. The former type was found more often in adults (96.3%) than in children (57.8%), while the latter was more frequent in children (42.2% as compared to 3.7% in adults). In both adults and children, cholesteatomas associated with poorly pneumatized mastoids showed mainly an attic and mastoid distribution communicating with a pars tensa or pars flaccida retraction or marginal perforation. Cholesteatomas associated with pneumatized mastoids appeared most often behind an intact drug (the so-called congenital cholesteatomas) and were distributed mainly in the tympanic cavity.

Adolescent↗
PubMed1994

The nasopharynx, eustachian tube and otitis media.

It has been classically hypothesized that a mass in the nasopharynx causes an obstacle to air flow through the eustachian tube, thereby creating a negative pressure in the middle ear followed by an effusion. However, examination of the relevant data concerning the supposed obstruction of the eustachian tube by nasopharyngeal carcinomas, choanal polyps and adenoids does not seem to support this cause and effect relationship. Evidence points to other more sophisticated mechanisms which cause negative pressure and an effusion in pathological middle ear conditions. While the hypothesis of a nasopharyngeal mass as the usual obstructive cause of middle ear effusion is hard to maintain, evidence does exist to support the origin of middle ear infection, as seen in acute and secretory otitis media, as being associated, at times, with an ascending infection from the nasopharynx.

Adenoids↗
PubMed1994

Tripod allograft in reconstruction of incudal lesions.

Long-term results of allograft ossiculoplasty with erosion of the long process of the incus in 44 patients are described. The pyramidal-shaped allograft leans on the stapes, the remaining part of the incus and the side of the malleus--forming a 'tripod' shape or construction. The study includes two groups of patients: group A (34 patients) in whom the pre-operative three-frequency average air-bone gap was 20 dB or more and group B (10 patients), in whom the pre-operative air-bone gap was less than 20 dB. In the latter group the indication for surgery was not their hearing loss, but a different pathological condition (infected retraction pocket, a cholesteatoma, etc.) which necessitated surgical disconnection of the chain during the operation. The average period of follow-up 46 months for group A and 24.9 months for group B. In group A, the preoperative average air-bone gap was 33 dB. Following surgery, the air-bone gap was 20 dB or less in 27 ears (79 per cent), and 10 dB or less in 18 of them (53 per cent). In group B, pre-operatively, the average air-bone gap was 11 dB. Following surgery, the air-bone gap was either better than before the operation or did not increase by more than 5 dB in eight patients (80 per cent). Comparison of the audiometric results of 20 patients after mean follow-up times of 23.8 months and 64.9 months shows that no deterioration of hearing occurred in the intervening period. Graft extrusion was not observed in any of the operated ears.

Adolescent↗
PubMed1994

Cholesteatoma: ossicular destruction in adults and children.

The records of 148 adults (aged 14 years and older) presenting previously untreated aural cholesteatomas are analysed with particular emphasis on ossicular destruction and other bony lesions in the middle ear. The findings are compared with those obtained in an earlier study of 63 children (aged 13 years and younger), also with untreated cholesteatomas. The rate of stapes and malleus destruction was similar in adults and children. The rate of incus destruction was significantly higher in adults. Semicircular fistulas as well as facial paralysis were also more prevalent amongst adults. Therefore, the notion of childhood cholesteatoma aggressiveness cannot be related to its effect on these bony structures. It may stem from its higher recurrence rate and from the more troublesome post-operative mastoid cavities, which are often larger in children than in adults.

Adolescent↗
PubMed1993

Treatment of cholesteatoma and retraction pockets.

Treatment of retraction pockets (RP) and cholesteatomas depends on their nature and evolvement and the size of mastoid pneumatization. RP are secondary to vacillating middle ear negative pressure. Treatment when necessary consists of placing a ventilating tube, excision of the RP or both. In most children and adults, cholesteatoma is derived from RP (or "atelectasis") of the tympanic membrane, where it can be termed "retraction pocket" cholesteatoma or "secondary" cholesteatoma. This type of cholesteatoma is associated with a non-pneumatized mastoid coupled by negative pressure. Approximately one-third of children's cholesteatomas present clinically behind an intact drum despite a pneumatized mastoid. Pathogenetically this type may be "congenital" or "metaplastic" and should be best termed "primary" cholesteatoma. Central perforations associated with cholesteatoma are probably derived from continuous tympanic membrane destruction by infection in cases of RP cholesteatomas or due to a primary cholesteatoma bursting out from the tympanic cavity. Canal-up surgery of cholesteatoma fails in 60% of cases at Tel Aviv University because of the inherent tendency of the tympanic membrane to retract once again. Residual disease was found in our cases to be a lesser cause for failure. Treatment depends on the type of cholesteatoma, emphasizing small "radicals" in sclerotic mastoids. When a pneumatized mastoid is encountered, a posterior tympanotomy should be considered.

Adult↗
PubMed1993

Atelectatic tympanic membrane: histologic study.

This study aims to elucidate the morphological difference between the noncollapsible physiologic tympanic membrane (TM) and the collapsible atelectatic TM. Histologic examination of atelectatic TMs obtained at surgery from 16 ears revealed inflammatory changes and destruction of the pars tensa collagenous "backbone." The disappearance of the organized collagenous layer seen in atelectatic TMs explains their conversion from the stiff physiologic membrane to a flexible one. This in turn will convert the middle ear from a noncollapsible gas pocket to a partially collapsible gas pocket, in which minimal pressure of only a few millimeters of water can cause retraction or ballooning of the atrophic TM. These pressure differences are too small to equilibrate automatically the difference created with the atmospheric pressure. Integrity of the pars tensa collagenous layer thus appears to be essential for the proper mechanical functioning of the physiologic TM.

Ear Diseases↗
PubMed1993

Dynamic measurement of gas composition in the middle ear. I: Technique.

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.

Animals↗
PubMed1993

Dynamic measurement of gas composition in the middle ear. II: Steady state values.

On-line measurement of ME gas composition in normal middle ears of 5 anesthetized guinea pigs at an established steady state was performed by mass spectrometry. The mean values for the gas composition of the middle ear were found to be: PN2: 82.4%, PO2: 7.6% and PCO2: 10.0%. This composition is very different from that of atmospheric air, and very similar to the gas composition of mixed venous blood. Our conclusions are that the gas composition is basically controlled by interchange with gases present in the blood and not by introduction of air through the eustachian tube. It is therefore proposed that middle ear gas deficiency is secondary not to eustachian tube input failure but to excess loss of middle ear gas due to enhanced diffusion into the blood. This situation exists especially under inflammatory conditions when there is an enlarged number of blood vessels promoting increased gas diffusion into them. Under ordinary conditions this middle ear gas deficiency will probably cause no significant underpressure because the mastoid pneumatization will act as a pressure buffer. When mastoid pneumatization is lacking, as happens in the otitis media syndrome, a pathological negative pressure will ensue.

Animals↗
PubMed1992

The correlation of middle ear aeration with mastoid pneumatization. The mastoid as a pressure buffer.

Atelectatic ears, which by definition are poorly aerated, are also usually associated with poor mastoid pneumatization. On the other hand, otosclerotic patients, whose middle ears are usually exceptionally well aerated, also have excellent mastoid pneumatization. Three unusual cases are presented, in which partial atelectasis developed in stapedectomized patients. In each case the mastoid was later found to be nonpneumatized, and further analysis revealed that their stapes fixation had in effect most probably been of non-otosclerotic origin. Thus, although these three cases had at first appeared to represent exceptions to the general rule of otosclerotics having a well-aerated middle ear, in fact they support the association between atelectasis and poor pneumatization. The linkage of good middle ear aeration with large mastoid pneumatization and vice versa may suggest that the mastoid plays a role of a pressure buffer in the middle ear, which is a system of a gas pocket with fluctuating pressures. Also, otosclerosis may be considered to be an unlikely cause of conductive deafness in cases of poor pneumatization.

Adult↗
PubMed1991

The effect of mastoid surgery on atelectatic ears and retraction pockets.

Forty children and 53 adults with a total of 111 atelectatic ears were operated on and followed up. Eight-four ears underwent tympanoplasty, while 27 ears underwent both a tympanoplasty and a mastoid operation. There were no statistically significant differences between the two operation groups as far as their age groups and the extent of the disease present. After follow-up of over 4 years, aeration of the middle ear was found to be better in the tympanoplasty group alone when compared with ears with also had mastoid operations.

Adolescent↗
PubMed1991

The influence of ventilating tubes on the surgical treatment of atelectatic ears.

Forty children and 53 adults having 111 atelectatic ears were operated on and followed up. All patients underwent a tympanoplasty operation, while 27 patients underwent concomitant various mastoid operations. A ventilating tube was inserted in 55 out of the 111 atelectatic ears, while in 56 ears the tympanoplasty was left without a ventilating tube. After an average of 53.1 months of post-operative follow-up we found that all ears were adequately aerated as long as a ventilating tube was in place. However, at the final check, once all ventilating tubes extruded, it was found that insertion of a ventilating tube at operation did not change the natural evolution of the atelectatic condition after surgery. Our conclusion is that the only way to overcome the atelectatic prone condition is to reinsert a ventilating tube whenever atelectasis reformation occurs.

Adolescent↗
PubMed1991

The histological patterns of normal and inflamed middle ear mucosa.

Thirty temporal bones from infants up to the age of 24 months were chosen randomly. Bones were sectioned serially and studied histologically. Inflammatory cellular and mucoid elements were identified and evaluated semiquantitatively. Some inflammatory infiltration was found in all 30 ears. Seven ears from infants up to 1 month of age presented inflammatory infiltration only. Twenty-three ears presented both cellular and mucoid elements. All temporal bones exhibiting mucoid elements showed concomitant cellular inflammatory infiltration. Practically no temporal bones in this age group were free of inflammatory elements, with secretory features appearing chronologically after the cellular ones.

Child, Preschool↗
PubMed1991

Adenoidectomy in otitis media. A review.

For many years adenoids were thought to affect adversely middle ear (ME) aeration by obstructing the eustachian tube opening, leading to ME infections and effusions. Consequently, the adenoids have often been removed in children suffering from ME diseases; indeed, adenoidectomy is still performed around the globe on millions of children annually. Opinions vary, however, on the usefulness of the operation in various ME diseases. The purpose of this study is to review the available studies concerning the relationship of adenoids to the ME as well as the effect and benefit of adenoidectomy on ME effusions and ME infections.

Acute Disease↗