OSTEOINDUCTION USING BONE MORPHOGENIC PROTEIN IN IRRADIATED TISSUE

Objective: To prove the efficacy of bone morphogenic protein as an ost eoinductive agent in irradiated tissue. Design: Prospective randomized controlled trial designed to test the effectiveness of recombinant bo ne morphogenic protein 2 (rBMP-2) combined with solid hydroxyapatite d isks in an irradiated tissue bed. Subjects: Eighteen adult, male, whit e New Zealand rabbits weighing 3.0 to 3.5 kg. Intervention: The rabbit s were randomly divided, with 9 receiving radiation treatment and 9 re ceiving no radiation treatment. Each animal underwent implantation of 2 hydroxyapatite disks onto the snout at 9 weeks following radiation t reatment. One disk was impregnated with rBMP-2 and the other with buff er only. The animals were killed at 3, 6, or 20 weeks after implantati on for analysis.Results: Histological analysis demonstrated that rBMP- 2 was equally effective as an osteoinductive agent in the irradiated a nd nonirradiated tissue. We also found significantly increased new bon e formation in the rBMP-2 group vs the buffer group. Conclusions: This study supports the potential clinical utility of rBMP-2 and solid hyd roxyapatite in irradiated tissue beds. These findings have interesting implications for patients with head and neck cancer who have undergon e radiation therapy and need bony reconstruction.