1996 Volume 39 Issue 2 Pages 150-157
On-line measurements of the pressure and volume of the middle ear cavity were performed in thirty six cases of OME in children with insertion of ventilation tube, at 14 days, 1 month, 3 months, 6 months, 12 months and more than 18 months after the insertion of a tympanostomy tube. The data of the pressure andvolume were investigated together with the degree of mastoid pneumatization on X-ray film and the histopathological changes of middle ear mucosa samples which were taken during insertion of middle ear ventilation tube. We classified changes in the epithelium and subepithelial layer of the middle ear mucosa samples into 4 categories according to our inflammatory criterion.
Our observation showed that the coefficient of correlation in comparing the data of the volume of middle ear cavity to the data of the degree of pneumatization on X-ray film was highest at three and four months after insertion of tympanostomy tube. This correlation indicated that the hypertrophied mucosa by the inflammation of OME turned to the normal thickness of mucosa until this time. The pressure of middle ear cavity was lowest at this same time and after that it elevated gradually. The recovery rate of elevation of the middle ear pressure was closely related to the histopathological changes of middle ear mucosa. Regarding the recovery rate of the middle ear pressure, significant difference could be distinguished in comparing the data of the low inflamed group to the data of the high inflamed group. In high inflamed group, it took more than one year when the pressure turned to the normal level.
This study showed that, after the insertion of tympanostomy tube in OME cases, the measurementsof pressure and volume of middle ear cavity was useful to evaluate the recovery phase of OME and to understand when to remove the tympanostomy tube.
