Osteoinductive substances in middle ear surgery.

There have been a number of stages in the development of cholesteatoma surgery. After the introduction of the radical operation the disadvantages of this procedure led to the development of more conservative operative techniques, for example the anterior-posterior approach with preservation of the posterior wall of the external ear canal or the obliteration of the mastoid cavity with muscle flaps or various materials. The assumption that organic fragments of the bone enable certain unspecified mesenchymal cells to form bone led to this investigation. Allogenic bone matrix and gelatin were implanted in the epitympanic recess in 16 rabbits. The animals were sacrificed 2, 4, and 8 weeks after the operation and the temporal bones were examined histologically. Both the implanted substances led to the formation of new bone in the epitympanic recess in rabbits. The newly formed bone bonded itself with the bony wall of the epitympanic recess. The existence of foreign body giant cells could not be verified. Perhaps the difficulties involved in treating cholesteatomas could be solved with osteoinductive substances.