动态MRI评估过伸性颈椎损伤发生过程中椎管内容、椎体及椎间盘相关变化的意义

MRI evaluation on content of vertevral canal, correlated changes of vertebral body and intervertebral disc in the process of ceruical uertebra injury

目的:通过动态MRI测量,观察颈椎病患者的颈椎管内容、椎体及椎间盘的动态变化对过伸颈椎损伤发生中的意义。方法:对31例不同程度颈椎退行性变患者中立位MRI扫描后,再行过屈、过伸位扫描。测量三位置下C各节段脊髓、硬膜囊中矢径、硬膜囊3～7前间隙及椎管、椎体矢径,进行统计学处理后分析其动态变化。结果:高位颈椎C4以上脊髓、硬膜囊中失径在三位置下差异无显著()性意义。C4以下则差异有显著性意义(P<0.05或P<0.01),椎体水平三位置中测得中矢径数值大小排列为:过伸位>中立位>过屈位;在椎间隙水平,因退行性变、膨出或突出椎间盘及黄韧带的影响则相反为:过屈>中立>过伸,且差异有显著性意义。本组有14例颈椎管狭窄其椎管、椎体比值<0.75,占45.16%(14/31)。结论:过伸位时颈脊髓和硬膜囊直径变粗,加上退行性变膨出或突出椎间盘和后方折叠内陷黄韧带致椎管容积相对狭窄加重,是过伸性颈椎损伤产生的机制所在,且常发生于下颈椎。对发育性颈椎管狭窄者更易患过伸性损伤。

AIM:To investigate the significance of the content of cervical spinal canal of the cervical syndrome patients, the development of vertebral body and intervertebral disc in the happening of injury of ceruical uertebra under MRI scanning. METHODS:In neutral position 31 cases of cervical spondylosis were under MRI scanning,and then were taken in hyperflex and hyperextension scanning.The central sagittal diameters of spinal cord, dural sac,vertebral body and spinal canal,herniated disc and anterior gap of dural sac in C3-7 of three positions were measured.The development was analyzed statistically after treatment. RESULTS:There were no significant difference in central sagittal diameters of dural sac and spinal cord above C4 level,and there were significant differences(P< 0.05 or P< 0.01) below C4 level.In vertebral level, the sagittal diameter of dural sac and spinal cord were as the following orders:hyperextension >neutral >hyperflex.But in intervertebral level, because of the degenerated disc and flavum ligament, the order were reverse as followsing:hyperflex >neutral >hyperextension.The difference was significant.As for 14 cases(taking up 45.16% in total)(14/31)were cervical spinal stenosis,the ratio of spinal canal and vertebral body was less than 0.75. CONCLUSION:Spinal cord can be severe injured in hyperextensive position and often in lower cervical spine with developmental cervical stenosis.The reason is heavier compression on the sac and cord by degenerated disc and flapped flavum ligament which increase the stenosis in hyperextension when the diameter of dural and spinal cord is increased.