Effect of different bone graft materials and methods on bone fusion for lumbar spondylolisthesis

BACKGROUND: The factors to affect spinal fusion are suitable bone graft location, good graft bed, enough bone grafts, strict fixation measure and enough fixation time. However, it is unclear which method should be used between intervertebral bone grafting and intertransverse bone grafting, as well as which material should be used between autogenous iliac bone and autogenous spinous process and vertebral lamina of resection. OBJECTIVE: To compare the fusion rate and improvement of clinical symptoms among different bone graft materials and methods which used in bone fusion for lumbar spondylolisthesis. DESIGN: A control observational experiment. PARTICIPANTS: A total of 92 patients with lumbar spondylolisthesis who received bone fusion treatment. According to Meyerding classificantion, there were 50 cases of degree I, 40 cases of degree II, 1 case of degree III, and 1 case of degree IV. There were 1 case in L sub(3), 58 cases in L sub(4), and 33 cases in L sub(5). METHODS: All patients received spinal canal decompression. After reduction and fixation was performed by spondylolisthesis reduction system (SRS), bone grafting fusion was performed in all patients. They were divided into four groups: autogenous spinous process and vertebral lamina graft placed between transverse processes group (n=21), autogenous spinous process and vertebral lamina graft placed between the vertebral bodies group (n=27), autogenous iliac bone graft placed between transverse processes group (n=21), autogenous iliac bone graft placed between the vertebral bodies group (n=23). MAIN OUTCOME MEASURES: The fusion rate and the improvement of clinical symptoms were evaluated according to the X-ray pre and post operative, as well as the JOA score. RESULTS: At 6 months after operation, the fusion rate in the autogenous iliac bone graft placed between the vertebral bodies group were significantly higher than that in the other three groups (P < 0.05). But at 9 and 12 months after operation, there was no significant difference in the fusion rate in the autogenous iliac bone graft placed between the vertebral bodies group compared with the other three groups (P > 0.05). According to the JOA score, at 6, 9, and 12 months after operation, there were no differences in the score among the four groups. CONCLUSION: Posterior bone graft fusion of the vertebral body or transverse process using the vertebral lamina, spinous process, or iliac bone as autograft along with internal fixation for lumbar spon