Absorbable gelatin sponge (Gelfoam) in otosurgery: one cause of undesirable postoperative results?

Absorbable gelatin sponge (Gelfoam)--commonly used in otosurgery--was gently inserted or firmly packed into the middle ear cavities of rats. The postoperative changes were evaluated 2 to 3 months later when, apart from some air-filled canals leading from the tympanal orifice of the Eustachian tube towards the attic, the middle ear cavity had become filled with newly formed bone and an amorphous mass of adhesions and bridles. The mass consisted of loose connective tissue, with fibroblasts, vessels and inflammatory cells. The tympanic membrane was retracted and fixed to the promontory. There were no signs that any Gelfoam had been removed through the Eustachian tube. The authors proposed that similar tissue reactions may occur in tympano-plasties.