Viscosity of effusion in the middle ear and eustachian tube in patients with otitis media with effusion

The viscosity of middle ear effusion (MEE) in the tympanic cavity and in the bony portion of the eustachian tube (ET) was compared in 11 specimens (10 patients) with otitis media with effusion (OME). Twenty microliters of effusion from the bony portion of the ET was sampled through myringotomy on the anterosuperior quadrant of the tympanic membrane with a micro-syringe with a curved needle. MEE in the hypotympanum was also sampled by separately puncturing the posteroinferior quadrant of the tympanic membrane. Using the microviscometer developed by one of the authors, the relative viscosity of these effusions were measured, and their natural logarithmic values were compared between the two sites mentioned above in each patient by obtaining their ratios (ET/ME). Effusion was found to have a significantly higher viscosity in the bony portion of the ET than in the hypotympanum (paired t-test: t = 3.859, p less than 0.01). In two patients with OME (serous mastoiditis) due to radiation to the temporal region, the ratios of the viscosity were comparatively small. On the other hand, excluding these two patients with serous mastoiditis mentioned above, the ratios were highest in two patients with a history of more than 60 days of hearing loss. These results were considered to be a clue to the possibility that viscous effusion aggravates ET function as a result of OME.