THE RELATIONSHIP BETWEEN THE DEGREE OF CHRONIC MIDDLE-EAR INFLAMMATION AND TYMPANIC BULLA PNEUMATIZATION IN THE PIG AS ANIMAL-MODEL

The relationship between the degree of chronic middle ear inflammation and pneumatization was investigated in the pig as an animal model, si nce its tympanic bulla closely resembles the human mastoid air cell sy stem. Ten piglets (sire: Landrace-Hampshire crossbreed; dam: Duroc) we re used for this experiment. Four ears of two animals served as the no rmal control group and 16 ears of eight animals were the experimental group. In this latter group, otitis media was induced by injecting gly cerin into the middle ear clefts 1 month after birth, and the degree o f inflammation was varied by administering or withholding antibiotics (cefamandole and dibekacin) and adjusting the dosage regimen. The anim als were sacrificed 6 months after birth and examined for the relation ship between the degree of chronic middle ear inflammation present and tympanic bulla pneumatization. Various degrees of inflammation were s uccessfully induced by injecting the antibiotics: the more severe the inflammation found, the greater was the inhibition of pneumatization. Findings demonstrated that the degree of inhibition of pneumatization produced was directly proportional to the severity of chronic middle e ar inflammation.