ハイドロキシアパタイト・リン酸カルシウム複合体を用いた眼窩形成後に生じた眼窩内無菌性嚢胞の１例

抄録

　　Mixed implants comprising hydroxyapatite granules and tricalcium phosphate composite（HAP/TCP）are expected to be histotropic and result in a lower frequency of foreign body reaction. We report a case of postoperative aseptic cyst after reconstruction of the orbital medial wall and floor using two HAP/TCP plates. The patient visited our hospital 3 years after reconstruction because of diplopia. Magnetic resonance imaging revealed a cyst on the artificial bone implant compressing the eyeball. The cyst and HAP/TCP were removed under general anesthesia. Although histological examination demonstrated surface ossification around the HAP/TCP, no bone fusion with surrounding bone was noted. Bacterial examination revealed the cyst to be aseptic. This supports the theory that repeated irritation due to two HAP/TCP plates causes inflammatory responses involved in cyst formation. This case suggested that long-term follow-up is necessary after reconstruction using HAP/TCP.