Effect of the Quantity of Intervertebral Bone Graft Material on Lumbar Intervertebral Fusion

Abstract：Objective To discuss and study the impact of the quantity of bone graft material on intervertebral fusion suc-cess rate. Methods We selected 98 patients with lumbar herniation,lumbar spinal stenosis or lumbar instability who had the lumbar posterior surgery in our hospital from January 2011 to December 2013. All patients were given the posterior decompres-sion,pedicle internal fixation and intervertebral bone grafting + spine cage implantation,respectively implant 4mL,5mL,and 6mL,implant the Cage after pressing,and press and fix the pedicle screw-rod fixation system. Respectively regular follow-up was conducted for the three groups of patients at 1 month,3 months,6 months and 12 months after the surgery,and conduct CT scan and patient function score detection;by the comparison of the three groups of patients in clinical effect improvement,bone grafting fusion rate,height change of intervertebral space and assess the postoperative effect of different quantity of bone graft materialon intervertebral bone graft fusion. Results All patients were followed up for 12 to 28 months with an average of 21 months. VAS scores of the three groups were improved significantly(P < 0. 05),but the difference among the three groups was not statistically significant(P > 0. 05);ODI scores of the three groups were improved significantly(P < 0. 05),but the differ-ence among the three groups was not statistically significant(P > 0. 05);If the clinical results was evaluated according to Mac-nab criteria:the excellent rate in group A was 90. 3% ,group B was 91. 0% ,and group C was 91. 2% ,and the difference a-mong the three groups was not statistically significant(P > 0. 05);at last follow-up,height change of intervertebral space of group A,B,and C were respectively(8. 7 ± 1. 7),(9. 8 ± 1. 7),and(10. 1 ± 1. 8)mm,and the difference was not statistically significant(P > 0. 05). According to the CT scan after one year of the surgery,there were high intervertebral fusion rates a-mong the three groups,the fusion rates of group B and group C were significantly higher than that of group A,and the difference was statistically significant(P < 0. 05). Conclusion In this experiment,different quantity of bone graft material showed no significant difference in improving postoperative symptoms,but with the increase in quantity of bone graft material,postopera-tive radiographic evaluation results showed that the greater the quantity of bone graft material,the higher the early graft fusion rate,which decreased the intervertebral space height loss. Long-term follow-up showed there was non-fusion risk if the quantity of bone graft material was less than 5mL. So it is recommended that the quantity of intervertebral bone graft material should be up to 5mL or more.