Evaluation of antibiotic-supplemented bone allograft in a rabbit model

The use of an antibiotic-supplemented bone allograft (ASBA) as a material for placement in infected mandibular fractures was investigated in a rabbit model. In phase I of this project, fractures were created in the mandibles of 30 New Zealand white rabbits and injected with 5 x 10(6) colony-forming units of Staphylococcus aureus and Bacteroides melaninogenicus. The animals were divided into three treatment groups (A, B, or C) and treated with conventional treatment (CT), CT plus demineralized bone powder, or CT plus ASBA. In phase II, bone defects were created in the mandibles of 17 New Zealand white rabbits and then grafted with ASBA. Assessment of healing and vascular ingrowth was made at 2-day intervals through 3 weeks postoperatively, and then weekly until termination at 60 days postoperatively. Phase I results showed significantly enhanced healing in the ASBA-treated group when compared with the other treatment methods and healed fracture strength, which was comparable to the nonfractured, contralateral mandibular angle. Phase II results demonstrated vascular structures in the ASBA material by 4 days postoperatively and osteogenesis by 12 days postoperatively.