In Brief:
Although the standard intertransverse fusion method employs autogenous iliac crest bone, autograft has certain limitations. Using contact microradiographs, backscattered electron imaging, and histology to evaluate bone formation at 6 and 12 months, we compared the long-term efficacy and safety of HealosMP52, an osteoinductive bone graft material, with that of autograft bone in a sheep model of posterior intertransverse process lumbar spinal fusion. Our data indicate that HealosMP52 exhibits safe and efficacious bone grafting properties and can potentially serve as an osteoinductive alternative to autograft bone in instrumented posterolateral spinal fusion.