ABSTRACT
Objective To evaluate the effects of allografi and rhBMP-2 in posterolateral lumbar spinal fusion in a rabbit model.Methods Thirty rabbits were randomly divided into three groups:autogenous lilac crest bone graft group,rhBMP-2/allograft composite group,and allograft group.The animals were killed and sampled six weeks after the surgery.The lumbar intertransverse process fusion for the animals was assessed by manual palpation,biomechanical testing,radiography,histology and quantitative histology of spine fusion mass in a 6-week observation.Results The ratio of fusion in rhBMP-2/allograft composite group(90%)was significantly higher than that in autogenous lilac crest bone graft group(40%)and allograft group(20%)(P＜0.05).The autogenous lilac crest bone graft group and rhBMP-2/allograft composite group showed significantly higher uniaxial tensile strength than allograft group.The au- togenous lilac crest bone graft group and rhBMP-2/allograft composite group also showed significantly more new bone formation than allograft group,but there was no significant difference between the former two grnups.Conclusion rhBMP-2/allograft composite may be an ideal substitute for autograft in lumbar spinal fusion.