Healing of experimental labyrinthine fistulas; further observations.

IN A PREVIOUS REPORT 1 it was pointed out that the closing of a labyrinthine fistula by new bone may occur from two sources, the periosteal surface and the endpsteal surface of the fistula. Factors which influence osteogenesis at these two surfaces were discussed. In addition to the problem of osteogenetic closure of the fistula, experience with human subjects 2 has focused attention on a further problem which may influence the functional result, the occurrence of a depression of hearing due apparently to an involvement of the sense organ of the cochlea which has been referred to as "postoperative labyrinthitis." The present report will be limited to the first of these problems, particularly to the prevention of the bony closure that originates from the periosteal surface. A number of observations relating to this problem were presented two years ago 1 and may be summarized: Meatal skin flap. In the monkey's ear bony