Osteogenic protein-1 : a review of its utility in spinal applications.

The potentially revolutionary effect that bone morphogenic proteins (BMPs) could have on orthopaedic surgery has fueled an exhaustive research effort that continues today. Upwards of 1.5 million bone-grafting operations take place in the US annually, with the anterior and posterior iliac crest being the most common donor site for autologous bone graft. Harvesting autologous bone graft, however, is not benign. It is postulated that a synthetic bone graft containing BMPs would possess the characteristics of autologous bone that allow new bone formation: osteogenesis, osteoinduction, and osteoconduction, without the negative repercussions related to bone harvesting. As a result of the ensuing research following their discovery some 40 years ago by Marshall Urist, the basic science behind BMPs has been largely uncovered. New information on BMPs now comes from clinical trials regarding their utility and efficacy in surgical applications. To date, BMPs have been studied in skeletal bone surgery throughout the body, and have been found to be particularly useful in surgical applications such as spinal arthrodesis. Osteogenic protein-1 (OP-1), or recombinant human BMP-7, is one subtype of BMPs that has shown particular potential in clinical trials. Pre-clinical and clinical studies have, thus far, garnered OP-1 a Humanitarian Device Exemption approval for spinal applications in the US. As clinical trials with larger patient numbers and longer clinical follow-up are completed, the usefulness of OP-1 as a bone graft substitute will be better elucidated.