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 disadvan tages of this procedure led to the development of more conservative op erative techniques, for example the anterior-posterior approach with p reservation of the posterior wall of the external ear canal or the obl iteration of the mastoid cavity with muscle flaps or various materials . The assumption that organic fragments of the bone enable certain uns pecified mesenchymal cells to form bone led to this investigation. All ogenic bone matrix and gelatine were implanted in the epitympanic rece ss in 16 rabbits. The animals were sacrificed 2, 4, and 8 weeks after the operation and the temporal bones were examined histologically. Bot h the implanted substances led to the formation of new bone in the epi tympanic recess in rabbits. The newly formed bone bonded itself with t he bony wall of the epitympanic recess. The existence of foreign body giant cells could not be verified. Perhaps the difficulties involved i n treating cholesteatomas could be solved with osteoinductive substanc es.