中耳手術におけるアパタイトの応用

Abstract

A closed technique of the middle ear surgery for cholesteatoma has been widely used because an open method has disadvantage to form a wide cavity and debris accumulation. However, elimination of the bony bridge is sometimes necessary for complete removal or debridement of the cholesteatoma matrix. In such a procedure, it becomes important to reconstruct the bridge which can protects postoperative retraction of the ear drum and succeeding so-called pocket formation. For the purpose of bridge reconstruction, we try to use sintered hydroxyl apatite ceramic.Preceding the clinical application, an animal experiment was performed, that is, the apatite was embedded in the tibia of the rabbit and postoperative course was observed. The experiment revealed that the apatite did not cause inflamatory or foreign body reaction in the surrounding tissue and adhered strongly to the host bone and the covering soft tissue.Following this animal experiment, we applied the porous apatite with 55% of pore rate, the same as used in the animal experiment, to the middle ear surgery. The apatite plate has a curvature to fit the external canal wall. After trimming of the apatite plate, it was inserted to the site of removed bridge and covered by fascia at the canal side. Mastoid cavity was obliterated by collagen sponges.Our 1 and 1/2 years experience with the use of the apatite is limited to 16 cases. Although the follow-up on these cases was too short for final evaluation, the initial results showed a satisfactory condition without infection or extrusion. We propose that this material can be valuable in the reconstruction of bony defect in the external ear canal.