Practical illustrations in tissue engineering: surgical considerations relevant to the implantation of osteoinductive...

This paper provides practical illustrations in the use of osteoinductive devices (biomaterial carriers coupled with osteoinductive morphogens) for bone tissue engineering. We discuss the considerations relative to the implantation of these devices that may induce tissues that are located outside the boundaries of the osteoinductive device as well as outside boundaries of the normal skeletal envelope. Five reports of osteoinductive devices generating such tissues are reviewed. Histologic and radiographic data from a sixth example are presented and compared with histologic and radiographic findings typical of two varieties of myositis ossificans. A theory is advanced that osteoinductive implants may induce ectopic tissues that resemble fibro-osseous pathologies. Finally characteristics of tissue-engineered bone graft substitutes that may contribute to development of these pathologies and device characteristics that may obviate these ectopic tissues are considered.