Tympanosclerosis of the ear drum in children

Morphological alterations in the tympanic membrane affected by tympanosclerosis: ultrastructural study

The ultrastructure of tympanoslerotic tissue, surgically excised from patients, has been studied with particular reference to the morphological changes of the connective tissue components and mineralization. Detailed analysis revealed the combination of degenerative and fibroplastic alterations, especially in the circular fibrous layer of the thickened lamina propria. In the biological material in this study the authors recognized different stages of calcium plaque development with discrete, moderate, and severe degree of mineralization. Extracellular matrix vesicles, with or without calcareous deposits, released by degenerating fibroblasts were prominent. In these biopsies no distinct morphological features of an inflammatory reaction were seen.

The inhibitory effect of topical N-acetylcysteine application on myringosclerosis in perforated rat tympanic membrane

OBJECTIVE

Myringosclerosis often occurs in patients in whom ventilation tube insertion and tympanoplasty procedures are performed. Recent studies have revealed a relationship between the development of myringosclerosis and oxygen-derived free radicals, and some investigations have demonstrated that free radical scavengers prevent the development of myringosclerosis. N-acetylcysteine is a well-known anti-oxidant and anti-inflammatory agent. In this study, we aimed to investigate the preventive effect of N-acetylcysteine on myringosclerosis in myringotomized rat tympanic membranes.

METHODS

Twenty Sprague-Dawley rats were bilaterally myringotomized and divided into four groups. Group 1 received no treatment, group 2 was treated with topical saline solution in Spongostan, group 3 received topical 0.6 mg N-acetylcysteine in Spongostan and group 4 received 1.2 mg N-acetylcysteine in Spongostan daily for 12 days. Tympanic membranes were examined by otomicroscopy on day 12. Then, the membranes were harvested and evaluated histologically by light microscopy.

RESULTS

The tympanic membranes of groups 1 and 2 (saline and non-treated) showed extensive occurrence of myringosclerosis, whereas groups 3 and 4 (treated with N-acetylcysteine) showed lesser occurrence of myringosclerosis in otomicroscopic evaluation (P<0.01). Under light microscopic examination, lamina propria of pars tensa was found thicker in groups 3 and 4 when compared with groups 1 and 2. There was no significant difference between groups 3 and 4 (P: 0.30).

CONCLUSIONS

Topically applied N-acetylcysteine was found to be effective in the prevention of sclerotic lesions in myringotomized rat tympanic membranes.

Quantitation and prevalence of tympanosclerosis in a pediatric otolaryngology clinic

OBJECTIVE

To determine the incidence and prevalence of tympanosclerosis (TS) in patients seen in a pediatric otolaryngology clinic.

DESIGN

Prospective observational study.

SETTING

Tertiary care, ambulatory care clinic.

PATIENTS AND OTHER PARTICIPANTS

We conducted a prospective observational study to determine the incidence of TS in 218 patients seen consecutively in a pediatric otolaryngology clinic for otologic and nonotologic reasons. The patient age range was 3 weeks to 30 years; 63% were male and 37% female. Of the 218 patients, 37% (81) had undergone bilateral myringotomy and tube placement (BM&T), and 35% (21) of the 81 showed signs of TS; 63% (137) of the 218 patients had no history of otologic surgery, but 12% (15) of the 137 showed signs of TS.

METHOD

The area of the tympanic membrane affected by TS was determined by otoscopy performed by one viewer, who drew the otoscopic findings on a standardized tympanic membrane template. The area of TS was quantified in terms of percentages by digital image analysis of the scaled drawings.

RESULTS

There was a range of 0.5-59.9% involvement of the tympanic membrane with TS, with the median percentage of involvement being 4.95%. There was an increased percentage of TS with repeat BM&T.

CONCLUSION

This observational study shows that patients who have had BM&T have a higher incidence of TS than those who have not had the surgery. However our findings also show that 38% of the patients in this study who had TS had never undergone BM&T.

New Aspects of Secretory Otitis Media, Eustachian Tube Function and Middle Ear Gas

The insertion of ventilation tubes to equalize pressure in the middle ear is the most common procedure used to treat otitis media. This article evaluates the advantages and drawbacks of ventilation and explores the various roles of the components of middle ear pressure, with special emphasis on oxygen-derived free radicals.

Immunohistochemical quantitation of collagen types I, II, IV and V in the ventilated and non-ventilated rabbit middle ear with otitis media with effusion

Morphometric quantitation of the area fractions of collagen types I, II, IV and V was determined in the normal rabbit middle ear mucosa and in relation to otitis media with effusion (OME) using a three-layered peroxidase-antiperoxidase technique. The effects of substituting normal low-oxygen middle ear gas (non-ventilated) with atmospheric air (ventilated) were studied in both healthy ears and ears with OME. Based upon previous histological examinations in rabbits, only ears with OME for more than 8 weeks were included to ensure the presence of chronic inflammation (COME). Atmospheric air was introduced into the middle ears by insertion of ventilation tubes or by an enlarged myringotomy. Collagen type I was predominant in all groups studied. The area fractions of collagen types I, II and IV were increased significantly in COME, with collagen type II elevated in particular. Ventilation of the normal ears resulted in a significantly increased area fraction of cells, while the area fractions and distributions of the collagen types were unaffected. None of the ventilated ears in COME improved or healed spontaneously. The total fraction of collagen in COME was not changed significantly by the introduction of atmospheric air. However, the individual distribution of the collagen types was altered, with significantly larger area fractions of types II and V found in ventilated ears with COME. Possible explanations for the differences found are discussed, including the role of oxygen-derived free radicals.

Atmospheric air vs. normal middle ear gas: effects on in vitro growth and collagen synthesis in normal middle ear fibroblasts

The present study was undertaken to quantitate the effects of atmospheric air and normal middle ear gas on cultured fibroblasts obtained from normal rabbit middle ear mucosa. The cells were exposed to three different gas compositions: 7% O2:5% CO2:88% N2, 21% O2:5% CO2:74% N2, and 75% O2:5% CO2:20% N2. The growth was monitored by measuring the total content of cell protein, the amount of DNA, and the cell division activity. The activity of the synthetic apparatus was determined by the collagen synthesis. For comparison, rabbit skin fibroblasts were grown under identical conditions. The results demonstrated significantly higher replication rate of middle ear fibroblasts at 7% oxygen than at atmospheric air whereas the collagen synthesis was significantly lower at 7%. Furthermore, the responses varied significantly between rabbit middle ear and rabbit skin fibroblasts. Thus the present study substantiates the hypothesis of an influence of atmospheric air on the middle ear mucosa which might be of importance, e.g., in relation to insertion of ventilation tubes or longstanding perforations of the tympanic membrane in otitis media.

Histological examination of the rabbit middle ear in secretory otitis media with and without a ventilation tube

To study the time-related histopathological lesions in secretory otitis media as it develops into the chronic stage, including the influence of ventilation of the middle ear, we examined the middle ear mucosa in a rabbit model. The observation period was from two weeks until 18 months. The histological method applied included haematoxylin-eosin and Sirius red staining for morphometric quantification of the goblet cells, the thickness of the connective tissue layer, the area fractions of blood vessels, inflammatory cells, fibroblasts and collagen fibres. In conclusion, the middle ear mucosa in secretory otitis media exhibited inflammatory changes correlating with the duration of the disease. Ventilation of the middle ear in secretory otitis media did not improve the changes.

Local application of N-acetylcysteine in secretory otitis media in rabbits

The middle ears of patients with secretory otitis media treated by ventilation tubes are exposed to two abnormal conditions: an inflammatory process and a hyperoxic condition. Both are known to cause changes in the mucosa, fibrosis in particular. N-acetylcysteine has been demonstrated to exhibit anti-inflammatory effects as well as being an oxygen radical scavenger. In an attempt to elucidate if N-acetylcysteine is capable of preventing the changes caused by secretory otitis media and ventilation tubes we administered different doses of the substance locally to the middle ear of an animal model. The results showed that N-acetylcysteine reduced the extent of the inflammation in the middle-ear mucosa and prevented the long-term fibrotic changes associated with secretory otitis media.

Alterations in tympanic membrane appearance and middle ear function in 11-year-old children with complete unilateral cleft lip and palate compared with healthy age-matched subjects

Forty-four 11-year-old children born with a complete unilateral cleft lip and palate were examined to determine the frequency and the extent of changes in the tympanic membrane and the middle ear function and compared with 16 healthy children of the same age. The incidence of hearing impairment, abnormal middle ear pressure, retraction of the pars flaccida and abnormal tympanic membrane appearance were 24, 44, 23 and 67% respectively among the patients while the same parameters in the control group were 0, 12.5, 6 and 12%. Previous grommet insertion in the patient group was statistically correlated to both tympanic membrane abnormality and abnormal middle ear pressure but, remarkably, no association was found between grommet insertion and hearing impairment. The poor middle ear function in the children with cleft lip and palate was probably a result of reduced Eustachian tube function.

Incidence and progression of myringo-incudo-pexy after secretory otitis

A cohort of originally 327 healthy children born in 1975 was followed by repeated otomicroscopies and tympanometries from age 5 to age 16 years, in total 9 otomicroscopies. Prevalence of drum pathology, especially myringo-incudo-pexy was investigated. Prevalence of myringo-incudo-pexy was 0.5% at age 5 years, 2.5% at age 7 and 4.2% at age 16. Forty percent of pexies were stable; 36% fluctuated and 26% disappeared. Hearing was surprisingly good at age 16, but the pexy represents a risk for progression.