2005 Experimental Study about the Effects of the Bone Cement leakage on the Intervertebral Disc in Vertebroplasty () 2005 4
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Experimental Study about the Effects of the Bone Cement leakage on the Intervertebral Disc in Vertebroplasty Abstract Objective: To study whether bone cement can lead to disc degeneration, and the correlation of degeneration degree to the time after operation, the doses and the kinds of bone cement. Materials and Methods: Sixteen majority canis familiaris (15 17kg) were randomly divided into 2 time groups. 5 lumbar intervertebral discs(l1/2l5/6) in every dog were classified into 3 groups (1 control group and 2 bone cement groups (PMMA and CPC)). Each of cement groups was classified into 2 dose subgroups (0.1ml and 0.3ml). X-ray was performed immediately after the dogs were anesthetized. Then, the dogs were stabbed by 18-gauge needle into the lumbar intervertebral discs, and cement was injected into them. Control discs were only stabbed and injected with nothing. X-ray, magnetic resonance image and histology of all discs were performed at 12 and 24 week after operation. The %Disc height index (%DHI) was calculated by comparing preoperative X-ray film with postoperative one. The T2-weighted mid-sagittal images of discs were analyzed qualitatively for evidence of degeneration. Quantitive analysis of these images was performed, MRI index (the product of nucleus pulposus area and average signal intensity) of each disc was calculated. We refered - III -
Masuda s standard of histological grading scale. By histology examination, discs were graded by assessing the annulus fibrosus, the border between the annulus fibrosus and nucleus pulposus, the cellularity of the nucleus pulposus and the matrix of the nucleus pulposus. The data were statistically analyzed by SPSS 10.0. Result: Intervertebral disc degeneration was not found in control groups. However, in bone cement groups, ruptured or serpentined patterned fibers, interrupted border between the annulus fibrosus and nucleus pulposus, decreased cellularity of the nucleus pulposus and condensed matrix of the nucleus pulposus, were found in histologic results. The degree of intervertebral disc degeneration in bone cement groups is varied with different observing timecement dose and cement category. The %DHI MR index and histology grade are not significantly different between two different time control groups under the t testp0.05. In 12 weeks group, there is significantly different between the control group and the bone cement groups under analysis of Variance (P<0.05), as well as in 24 weeks group (P<0.05). In 12 weeks group, the %DHI of PMMA-0.3ml group is significantly different with the control (P<0.05), while the %DHI of the other three groups has no significant difference with the control (P0.05), under Dunnet-t test. In 24 weeks group, the %DHI of the cement groups is significantly different with the control. No matter in the 12 weeks group or in the 24 weeks group, the MR index and histologic grade of cement groups - IV -
are significantly different with the control groupp0.05. There is significant difference between the different time different doses and different category of bone cement in cement bone groups under Univariate Analysis of VarianceP0.05). Conclusion: PMMA and CPC can lead intervertebral disc to degeneration. Intervertebral disc degeneration induced by PMMA is more serious than that of CPC. Intervertebral disc degeneration degree is correlative to the time after operation and the doses of bone cement. [Key word] Vertebroplasty; Polymethylmethacrylate; Calcium Phosphate Cement; Intervertebral Disc Degeneration; Radiology, interventional; Magnetic Resonance imaging. Written by: Zhao Hui Supervised by: Ni Caifang - V -
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110 100 DHI 90 80 21 70 PMMA CPC 60 12 24 PMMACPC%DHI 110 100 90 DHI 80 70 60 0.1ml 50 47 0.3ml 40 12 24 DHI - 7 -
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30000 20000 MR 10000 0 PMMA CPC -10000 12 24 CPCPMMAMR 30000 20000 MR 10000 0 0.1ml 0.3ml -10000 12 24 MR - 9 -