 Material One fifth of chronic patients with otitis media with effusion OME have no beneficial effect of balloon dilation 2. We hypothesize that contrast media will not pass through the bony part of the ET in a majority of these patients, while it does in a majority of the patients experiencing successful relief of disease after balloon dilation. Variation is not known, but is presumed not to exceed 20. Sample size calculation is not straight-forward in this case, handling dichotomous variables. Power calculation indicates a needed number of 80 individuals in the patient group to have a power of at least 80 for the detection of difference between these 2 groups with an alpha level of 5 with two-sided tests. Additionally, we include 15 controls with presumed healthy middle ears and ET to verify significantly better contrast media passage to epipharynx in these individuals than in the group of patients with chronic OME, based on similar power calculation. 