EXPERIMENTAL CHOLESTEATOMAS ARISING FROM AUTOLOGOUS FREE SKIN-GRAFTING IN THE MIDDLE-EAR CAVITY

An autologous free skin graft taken from the upper or the lower extern al ear canal or the auricle was implanted in the otic bulla of 28 guin ea pigs. An epidermal cyst simulating middle ear cholesteatoma was suc cessfully produced in 25 (89.3%) animals 8 weeks after grafting. Using this model, the histological reaction of middle ear granulation tissu e to the debris was studied. Cysts originated from the auricular skin showed the strongest activity with regard to growth rate, amount of de bris produced, and inflammatory reaction to the exposed debris. We con clude that the exposed debris plays an important role in chronic granu lomatous inflammation in association with cholesteatoma.