Search PubMed⌕ Search

Biomedical subjects

M Luntz

Publications and source records attributed to M Luntz.

At least 37 records · Page 2Linked to original sources
PubMed1997

Surgical techniques for cochlear implantation of the malformed inner ear.

OBJECTIVE: The objective was to describe surgical techniques helpful in implanting children with inner ear malformations. STUDY DESIGN: This was a retrospective chart review and description of surgical techniques in the setting of a tertiary referral center. PATIENTS: The study population was composed of 10 children with inner ear deformities who received 22-channel implants. RESULTS: The primary surgical challenges encountered in these procedures include complete electrode insertion, cerebrospinal fluid gusher, identification of cochleostomy site in the absence of the round window and aberrant facial nerve, and fixation and stabilization of the electrode. CONCLUSIONS: The techniques described allow safe and effective insertion of multichannel electrodes in patients with inner ear malformations.

Child↗
PubMed1996

Otitis media in children with cochlear implants.

Fifty children who received a cochlear implant between 1991 and 1995 were evaluated for incidence of acute otitis media (AOM). Thirty-seven (74%) children had AOM before implantation and 8 (16%) after implantation. All children who had AOM after implantation had a history of AOM. A subgroup of 14 children required ventilating tubes for recurrent AOM before implantation. Five (35.7%) in this group had AOM after implantation. The incidence and severity of AOM decreased after implantation. All episodes of postimplant AOM were successfully treated with routine oral antibiotics, and no infectious complications occurred. A history of recurrent AOM should not inordinately delay cochlear implantation.

Acute Disease↗
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↗
PubMed1996

Update on cochlear implantation.

Cochlear implants are computerized devices that partially replace the transduction and encoding functions of the cochlea. Over the past 20 years studies have demonstrated that cochlear implants are safe and effective, with modern computer-based multichannel devices providing open-set word understanding for the majority of implanted postlingually deafened adults as well as pre- and postlingually deafened children. Advances in word processing strategy have led to ever-improving word recognition skills and recent studies have demonstrated that oral language develops in congenitally deaf children who use cochlear implants.

Adult↗
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

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

Acute mastoiditis--revisited.

The clinical course and causative organisms were studied in 18 patients with acute mastoiditis, 13 of whom (72%) had no previous history of middle ear disease. Their age ranged from 5 months to 21 years, and duration of middle ear symptoms immediately prior to admission ranged from 1 to 45 days (average 9.7 days). None had undergone a myringotomy prior to admission, while 13 (72%) had been receiving antibiotic treatment for acute otitis media. Three were admitted with intracranial complications. Bacteria were isolated in 10 of the 16 patients in whom samples were available for bacterial culture, and included Streptococcus pneumonia (2), Streptococcus pyogenes (2), Staphylococcus aureus (2), Staphlococcus coagulase negative (2), Klebsiella pneumonia (1), and Pseudomonas aeruginosa (1). Of the 17 patients treated by us, 11 received surgery. Acute otitis media, secretory otitis media, acute mastoiditis, subacute mastoiditis and masked mastoiditis create a continuum. Antibiotic treatment for acute otitis media cannot be considered as an absolute safeguard against acute mastoiditis. When antibiotics are prescribed for acute mastoiditis before culture result is available, an anti-staphylococcal agent should be included. At least some patients with acute mastoiditis develop a primary infection of the bony framework of the middle ear cleft. The prevalence of the intracranial complications in acute mastoiditis is still high and may appear soon after or concomitant with the first sign of acute mastioditis.

Acute Disease↗
PubMed1993

Management of penetrating wounds of the neck.

Management policies for penetrating wounds of the neck vary from mandatory surgical exploration to selective surgical exploration following extensive or minimal imaging investigation. In order to review the treatment protocol at Sheba Medical Center, Tel Hashomer, Israel, we retrospectively studied 21 patients who were treated between the years 1984 and 1989. Thirteen had gunshot injuries and eight had stab wounds. Eight patients had undergone immediate exploration of the neck. Four patients had died, but all of these latter patients had evidence for significant bleeding that could have been detected within a short time of admission. On the basis of our findings and previous studies, we conclude that: presenting features of neck injuries should be differentiated into two basic categories: immediately life-threatening and not immediately life-threatening. Immediately life-threatening features include overt massive bleeding, expanding hematoma, non-expanding hematoma in the presence of hemodynamic instability, hemomediastinum, hemothorax, and hypovolemic shock. In all of these cases, immediate surgical exploration is mandatory. Non-life-threatening features include any signs of vascular complication in a hemodynamically stable patient, signs of upper aerodigestive tract lesions (when initial treatment has already relieved respiratory distress) and peripheral neurological deficits. These patients should undergo thorough imaging investigations on the basis of which the need for and the nature of possible surgical intervention can be determined.

Adolescent↗
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

Middle ear gases.

The ex vacuo theory, claiming that air enters the middle ear through the Eustachian tube and oxygen leaves it into the blood by diffusion, does not provide a complete explanation and description of the mechanism of middle ear aeration. This study shows that both the gas diffusion between the middle ear and the blood and the flow of gas through the Eustachian tube are bidirectional processes for all the gases concerned N2, CO2, O2 as well as H2O.

Adolescent↗
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

Induced atelectasis of the middle ear and its clinical behavior.

Atelectatic ears are often treated with ventilating tubes for long periods of time. However, a certain percentage of atelectatic ears and retraction pockets resolve spontaneously over time. In order to determine whether self-aeration had been achieved in atelectatic ears previously fitted with ventilating tubes, the tubes were sealed and the ears were then closely followed. Out of 37 such tests, atelectasis did not recur in 4 ears, allowing their ventilating tubes to be removed. In 33 tests atelectasis redeveloped within 1-2h after the ventilating tube was sealed, with ears reverting to the same degree and shape as the original atelectatic condition. The seals were then removed, resulting in resolution of atelectasis. These observations were enforced by previous observations of similar changes and suggest that the partial pressures of the blood gases may be an important factor in controlling the level and possibly also the pathogenesis of atelectasis. The method of testing described also can be used in selected cases to determine whether or not a given atelectatic ear still requires a ventilating tube.

Acoustic Impedance Tests↗
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↗