The effect of cement leakage occurred during vertebroplasty on intradiscal biochemistry variations

Objective: To investigate the effect of intradiscal cement leakage occurred during vertebroplasty on the changes of glycosaminoglycan contents in the disc, and to analyze the relationship of disc biochemistry to the time interval after the procedure, to the kinds of bone cement and to the amount of cement leakage. Methods: Sixteen adult dogs (15-17 kg) were randomly divided into 12-week group and 24-week group. Five lumbar intervertebral discs (L1/2-L5/6) in each dog were classified into 5 groups: one disc was used as control group and the remaining four discs were used as bone cement groups (PMMA and CPC). Each of cement groups was classified into 2 dose subgroups (0.1 ml and 0.3 ml). The lumbar intervertebral discs of the dog were punctured with an 18-gauge needle, and bone cement was injected into them in cement groups. Control discs were only punctured and injected with nothing. The contents of glycosaminoglycan in the annulus fibrosus and nucleus pulposus of discs were determined and were analyzed for their biochemical properties. ANOVA and Scheffe-test were used to make the statistical analyses. Results: In control group, the contents of glycosaminoglycan in annulus fibrosus and nucleus pulposus were not significantly different between 12-week group and 24-week group (P<0.05). In 12-week group, significant difference in the contents of glycosaminoglycan existed between the control group and the bone cement groups when analysis of variance was used (P<0.05), and the same result was observed in 24-week group (P<0.05). By using Scheffe test, no matter in the 12-week group or in the 24-week group, the contents of glycosaminoglycan in annulus fibrosus and nucleus pulposus of cement groups were significantly different from those of the control group (P<0.05). Significant difference existed between the groups with different time interval, using different doses and belonging to different category of bone cement in bone cement groups when univariate analysis of variance was employed (P<0.05). Conclusion: The contents of glycosaminoglycan in annulus fibrosus and in nucleus pulposus show some changes after intradiscal cement leakage. And these changes are obviously related to the time interval after operation, the category of cement and the amount of cement leakage. (authors)