Seromucinous otitis media and its sequelae. (A retrospective study of 242 children)

The effect of anaesthesia on tympanograms of children undergoing grommet insertion

A prospective study was designed to assess the effect of anaesthesia, including nitrous oxide, on tympanometric results of children undergoing myringotomy and possible grommet insertion. 155 patients (310 ears) were examined with a pneumatic otoscope and had tympanograms performed within 1 hour of operation. The patients were then anaesthetized by a combination of intravenous and gaseous anaesthetic. Immediately before myringotomy, a tympanogram was repeated. In 13% of patients predicted to have fluid at admission, there was a change in their tympanogram after induction of anaesthesia, suggesting clearance of fluid. At myringotomy, these ears were dry. We surmise that there was displacement of fluid from the middle ear by nitrous oxide during the early stages of anaesthesia. Thus we feel that, if an otologist confidently expects to find an effusion at myringotomy, the presence of a dry tap should not change his management plan.

Tympanosclerosis of the ear drum in children

Tympanosclerosis of the ear drum in children is associated with secretory otitis media. The tympanosclerotic changes affect the pars tensa and seem to be a dynamic process of new formation together with regress and restoration to normal tissue. Our study includes 90 cleft palate children followed for 7.8 years with a total of 2068 examinations. During the observation period 59% of the ear drums were affected by tympanosclerosis, while only 42% had tympanosclerosis at the last examination. The tympanosclerotic lesion of the ear drum disappeared completely in 30%, seemed stable in 40% and tended to grow steadily in 30% of the ear drums affected. The pathogenesis of tympanosclerosis is not clear, although the inflammation known to exist in secretory otitis media probably plays an important part.

Secretory otitis media in children. (A retrospective study of 249 cases)

A retrospective study of 249 children with secretory otitis media is presented. Recurrence rates and complications encountered are recorded. In cases of unilateral secretory otitis media, it is recommended that a grommet should not be inserted in the second (dry) ear, as the chance of fluid occurring in that ear later was only 0-12 per cent. When both ears are found to be dry, again it is recommended that grommets should not be inserted, as the chances of grommet insertion becoming necessary later were only 5.5 per cent. It is concluded that myringotomy, with or without grommets, is a beneficial operation with minimal complications.

Effect of prostaglandin on the composition of chinchilla middle ear effusion

Prostaglandins (PGs) are naturally occurring, cyclic, unsaturated fatty acids which possess a wide range of potent biological activities. PGs have been found in human middle ear effusions and might have implications for understanding the inflammation and possibly the bone resorption seen in chronic otitis media. We have measured PGs by radioimmunoassay in middle ear effusions (MEE) from experimentally induced serous otitis media (SOM) and purulent otitis media (POM) in chinchillas. PGE2 levels were significantly higher in the POM group compared to the SOM group. We have also demonstrated that chinchilla middle ear mucosa can convert arachidonic acid (AA), a precursor of PGs, to PG by injecting 14C-AA into bullae and assaying using radiochromatography. This conversion was completely blocked by both indomethacin and aspirin given orally or by direct injection into the middle ear. We then injected 50 microgram of PGE2 into chinchilla bullae to assess its effect on the composition of MEE. First, the time course of PGE2 metabolism after its injection into the middle ear (ME) was determined by thin-layer chromatography (TLC) of labelled and unlabelled PGE2. Following this, serial daily injections of PGE2 and normal saline as control were made for one, three, and seven days. MEE and serum were collected and assayed for lactate dehydrogenase (LDH), acid and alkaline phosphatase, calcium, protein and hexosamine. Compared to the control, the levels of LDH, acid and alkaline phosphatase, calcium and protein were significantly elevated. Hexosamine levels were higher than the control at one and three days but did not differ significantly at seven days from the control. We have therefore demonstrated that chinchilla middle ear mucosa has the ability to synthesize PG from AA and suggest an active role for PGs in the inflammation and in the bone resorption seen in otitis media.

Otitis media with effusion: a steroid and antibiotic therapeutic trial before surgery

Eustachian tube dysfunction has been considered the main factor in the etiology of otitis media with effusion (OME). A short-term systemic steroid therapy, with combined chemotherapeutics, yielded 53.1% cure in 160 children in which OME had been diagnosed, whereas only 12.5% of similar 116 children were cured by chemotherapeutic treatment alone. It is postulated that steroids, acting by a mechanism much similar to the one in the newborn lung, increase the level of a tubal surface active agent, thus enhancing Eustachian tube refunctioning. This combined treatment, we believe, deserves its place as a routine conservative trial before surgery.

Comparative study of various ventilating tubes

In less than 20 years, insertion of middle ear ventilating tubes has become perhaps the most common operative procedure. It was not possible to find a study that adequately compares the performance of the many different types of tympanostomy tubes available. The ideal ventilating tube is defined; it has not yet been designed.

The value of impedance testing in diagnosis of middle ear effusion

An attempt is made to evaluate the role of impedance testing and pure tone audiometry in the diagnosis of middle ear effusions in children, by comparing the clinical predictions and the audiological predictions with the myringotomy findings. A number of cases are found to have unexpectedly dry middle ears, thus leading to a lower correlation rate for impedance testing in prediction of effusions, than in other published series. The possible explanations for this discrepancy are discussed.