Practical illustrations in tissue engineering: Surgical considerations relevant to the implantation of osteoinductive devices

This paper provides practical illustrations in the use of osteoinductive de vices (biomaterial carriers coupled with osteoinductive morphogens) for bon e tissue engineering. We discuss the considerations relative to the implant ation of these devices that may induce tissues that are located outside the boundaries of the osteoinductive device as well as outside boundaries of t he normal skeletal envelope. Five reports of osteoinductive devices generat ing such tissues are reviewed. Histologic and radiographic data from a sixt h example are presented and compared with histologic and radiographic findi ngs typical of two varieties of myositis ossificans, A theory is advanced t hat osteoinductive implants may induce ectopic tissues that resemble fibro- osseous pathologies. Finally characteristics of tissue-engineered bone graf t substitutes that may contribute to development of these pathologies and d evice characteristics that may obviate these ectopic tissues are considered .