Discogenic low back pain is a serious medical and social problem, and accounts for 26%-42% of the patients with chronic low back pain. Recent studies found that the pathologic features of discs obtained from the patie...Discogenic low back pain is a serious medical and social problem, and accounts for 26%-42% of the patients with chronic low back pain. Recent studies found that the pathologic features of discs obtained from the patients with discogenic low back pain were the formation of the zones of vascularized granulation tissue, with extensive innervation in fissures extending from the outer part of the annulus into the nucleus pulposus. Studies suggested that the degeneration of the painful disc might originate from the injury and subsequent repair of annulus fibrosus. Growth factors such as basic fibroblast growth factor, transforming growth factor β1, and connective tissue growth factor, macrophages and mast cells might play a key role in the repair of the injured annulus fibrosus and subsequent disc degeneration. Although there exist controversies about the role of discography as a diagnostic test, provocation discography still is the only available means by which to identify a painful disc. A recent study has classified discogenic low back pain into two types that were annular disruption-induced low back pain and internal endplate disruption-induced low back pain, which have been fully supported by clinical and theoretical bases. Current treatment options for discogenic back pain range from medicinal anti-inflammation strategy to invasive procedures including spine fusion and recently spinal arthroplasty. However, these treatments are limited to relieving symptoms, with no attempt to restore the disc's structure. Recently, there has been a growing interest in developing strategies that aim to repair or regenerate the degenerated disc biologically.展开更多
Background Previous studies have suggested that percutaneous vertebroplasty might alter vertebral stress transfer,leading to adjacent vertebral failure.However,no three-dimensional finite element study so far accounte...Background Previous studies have suggested that percutaneous vertebroplasty might alter vertebral stress transfer,leading to adjacent vertebral failure.However,no three-dimensional finite element study so far accounted for the stress distributions on different cement volumes.The purpose of this study was to evaluate the stress distributions on the endplate under different loading conditions after augmentation with various volumes of bone cement.Methods L2-L3 motion segment data were obtained from CT scans of the lumbar spine from a cadaver of a young man who had no abnormal findings on roentgenograms.Three-dimensional model of L2-L3 was established using Mimics software,and finite element model of L2-L3 functional spinal unit （FSU） was established using Ansys10.0 software.For simulating percutaneous vertebral augmentation,polymethylmethacrylate （PMMA） was deposited into the bipedicle of the L2 vertebra.The percentage of PMMA volume varied between 15％ and 30％.The stress distributions on the endplate of the augmented vertebral body were calculated under three different loading conditions.Results In general,the stress level monotonically increased with bone cement volume.Under each loading condition,the stress change on the L2 superior and inferior endplates in three kinds of finite element models shows monotonic increase.Compared with the stress-increasing region of the endplate,the central part of the L2 endplate was subject to the greatest stress under three kinds of loading conditions,especially on the superior endplate and under flexion.Conclusions The finite element models of FSU are useful to optimize the planning for vertebroplasty.The bone cement volume might have an influence on the endplate of the augmentation,especially the superior endplate.It should be noted that the optimization of bone cement volume is patient specific; the volume of the bone cement should be based on the size,body mineral density,and stiffness of the vertebrae of individual patients.展开更多
Background This study aimed to investigate the effect of pcDNA3.1-vascular endothelial growth factor （VEGF）165 vector on vertebral cartilage endplate vascular buds and intervertebral discs. Methods Rabbits were rand...Background This study aimed to investigate the effect of pcDNA3.1-vascular endothelial growth factor （VEGF）165 vector on vertebral cartilage endplate vascular buds and intervertebral discs. Methods Rabbits were randomly assigned to the control and experimental groups with 10 in each. In the experimental group, we anesthetized the rabbits and exposed the front vertebral body. Using the mark of the longitudinal ossature of the front vertebral body of the lumbar vertebrae, we advanced a needle at the central point of the front fourth and fifth lumbar intervertebral discs and injected 20 pl pcDNA3.1-VEGF165. Similarly, in the control group, we injected 20 IJl pcDNA3.1. At 4 and 8 weeks post-injection, we examined the changes of the vertebral cartilage endplate using X-ray radiograph, histology, and scanning electron microscopy. Results The vertebral cartilage endplate calcification and degeneration in the experimental group were less than those in the control group at 8 weeks post-operation. The average number and diameter of vascular buds obviously increased in the experimental group at 4 and 8 weeks post-operation. The number of vascular buds and the diameter in the region of the inner annulus increased when compared to those in the area near the nucleus pulposus. Conclusions The pcDNA3.1-VEGF165 plasmid can increase the average number and diameter of vascular buds and decelerate intervertebral disc degeneration.展开更多
文摘Discogenic low back pain is a serious medical and social problem, and accounts for 26%-42% of the patients with chronic low back pain. Recent studies found that the pathologic features of discs obtained from the patients with discogenic low back pain were the formation of the zones of vascularized granulation tissue, with extensive innervation in fissures extending from the outer part of the annulus into the nucleus pulposus. Studies suggested that the degeneration of the painful disc might originate from the injury and subsequent repair of annulus fibrosus. Growth factors such as basic fibroblast growth factor, transforming growth factor β1, and connective tissue growth factor, macrophages and mast cells might play a key role in the repair of the injured annulus fibrosus and subsequent disc degeneration. Although there exist controversies about the role of discography as a diagnostic test, provocation discography still is the only available means by which to identify a painful disc. A recent study has classified discogenic low back pain into two types that were annular disruption-induced low back pain and internal endplate disruption-induced low back pain, which have been fully supported by clinical and theoretical bases. Current treatment options for discogenic back pain range from medicinal anti-inflammation strategy to invasive procedures including spine fusion and recently spinal arthroplasty. However, these treatments are limited to relieving symptoms, with no attempt to restore the disc's structure. Recently, there has been a growing interest in developing strategies that aim to repair or regenerate the degenerated disc biologically.
文摘Background Previous studies have suggested that percutaneous vertebroplasty might alter vertebral stress transfer,leading to adjacent vertebral failure.However,no three-dimensional finite element study so far accounted for the stress distributions on different cement volumes.The purpose of this study was to evaluate the stress distributions on the endplate under different loading conditions after augmentation with various volumes of bone cement.Methods L2-L3 motion segment data were obtained from CT scans of the lumbar spine from a cadaver of a young man who had no abnormal findings on roentgenograms.Three-dimensional model of L2-L3 was established using Mimics software,and finite element model of L2-L3 functional spinal unit （FSU） was established using Ansys10.0 software.For simulating percutaneous vertebral augmentation,polymethylmethacrylate （PMMA） was deposited into the bipedicle of the L2 vertebra.The percentage of PMMA volume varied between 15％ and 30％.The stress distributions on the endplate of the augmented vertebral body were calculated under three different loading conditions.Results In general,the stress level monotonically increased with bone cement volume.Under each loading condition,the stress change on the L2 superior and inferior endplates in three kinds of finite element models shows monotonic increase.Compared with the stress-increasing region of the endplate,the central part of the L2 endplate was subject to the greatest stress under three kinds of loading conditions,especially on the superior endplate and under flexion.Conclusions The finite element models of FSU are useful to optimize the planning for vertebroplasty.The bone cement volume might have an influence on the endplate of the augmentation,especially the superior endplate.It should be noted that the optimization of bone cement volume is patient specific; the volume of the bone cement should be based on the size,body mineral density,and stiffness of the vertebrae of individual patients.
基金This study was supported by a grant from the National Natural Science Foundation of China，the Anhui Province Education Department Key Fund Project
文摘Background This study aimed to investigate the effect of pcDNA3.1-vascular endothelial growth factor （VEGF）165 vector on vertebral cartilage endplate vascular buds and intervertebral discs. Methods Rabbits were randomly assigned to the control and experimental groups with 10 in each. In the experimental group, we anesthetized the rabbits and exposed the front vertebral body. Using the mark of the longitudinal ossature of the front vertebral body of the lumbar vertebrae, we advanced a needle at the central point of the front fourth and fifth lumbar intervertebral discs and injected 20 pl pcDNA3.1-VEGF165. Similarly, in the control group, we injected 20 IJl pcDNA3.1. At 4 and 8 weeks post-injection, we examined the changes of the vertebral cartilage endplate using X-ray radiograph, histology, and scanning electron microscopy. Results The vertebral cartilage endplate calcification and degeneration in the experimental group were less than those in the control group at 8 weeks post-operation. The average number and diameter of vascular buds obviously increased in the experimental group at 4 and 8 weeks post-operation. The number of vascular buds and the diameter in the region of the inner annulus increased when compared to those in the area near the nucleus pulposus. Conclusions The pcDNA3.1-VEGF165 plasmid can increase the average number and diameter of vascular buds and decelerate intervertebral disc degeneration.
