正常颈椎功能单位动态MRI表现的初步研究

Preliminary study on kinematic cervical spine MRI for segmental motion in healthy individuals

目的:探讨正常颈椎功能单位的动态MRI变化,为脊髓型颈椎病的研究提供解剖学基础。方法:2015年3月~2017年6月招募40名健康志愿者,行常规的中立位、最大屈曲和最大后伸颈椎MRI扫描。测量3种体位正中矢状面颈椎不同节段的水平位移及角度位移,计算颈椎各节段及整体的活动度以及各节段运动百分数。采用成组设计多个样本的秩和检验比较3种体位不同节段水平位移及角度位移的差异。结果:40名受试者共240个椎间盘纳入研究,Miyazaki分级法Ⅰ级160个,Ⅱ级,69个,Ⅲ级11个。中立位及最大后伸位颈椎序列连续,水平位移均为零,最大屈曲位时4例颈椎序列异常,C3~4、C4~5及C5~6最大过屈位与中立位及最大过伸位水平位移差异有统计学意义(H=6.101,P均<0.05)。最大屈曲位、最大后伸位时颈椎不同节段角度位移可有不同程度的变化,3个不同体位在C3~4、C4~5及C5~6角度位移差异有统计学意义(H=20.471、20.812、55.038,P均<0.01),进一步比较,C3~4、C5~6中立位与过屈位和过伸位的角度位移差异均有统计学意义(P值均<0.05),C4~5中立位与过屈位的角度位移差异有统计学意义(P<0.05)。C4~5、C5~6、C6~7活动度及其对颈椎整体活动度的贡献均较大。结论:正常颈椎水平位移在最大屈曲和最大后伸时变化较小,角度位移在不同体位变化较大;C4~5、C5~6、C6~7活动度及其对颈椎整体活动度的贡献均较大。

Objective: To observe the changes of the functional spinal unit of the cervical spine under kinematic magnetic resonance imaging (MRI) in healthy individuals for anatomic basis for diagnosis of cervical spondylotic myelopath. Methods: MRI was performed to examine the cervical spines at neutral,maximum flexion and maximum extension position in 40 healthy volunteers between March 2015 and June 2017.Translational motion and angular variation were generated at the three positions at median sagittal plane using post-processing Functool software.Individual segmental and entire spinal motion as well as percentage for each segment was calculated.Kruskal-Wallis H-test was used to analyze the difference of the translational motion and angular variation at the three positions. Results: A total of 240 intervertebral discs were examined in the 40 subjects,of which 160 discs were in grade I,69 in grade II,and 11 in grade III by Miyazaki grading.Continuous sequences of cervical vertebrae were seen at neutral position and maximal extension position,with blank horizontal displacement.However,abnormal sequence was seen in 4 subjects by maximal extension position.The difference was significant in translational motion between maximum flexion and neutral and maximum extension position at segment C3-4,C4-5and C5-6( H =6.101, P< 0.01).Angular variation in certain degree was found at different segments by maximal flexion and extension position,and the variation was significant at the three positions at segment C3-4,C4-5 and C5-6( H =20.471;20.812;55.038,all P< 0.01).Further comparison indicated different angular variation at C3-4,C4-5,C5-6 by neutral and maximal extension position(all P< 0.05).C4-5,C5-6 and C6-7 were greatly associated with single motion and total angular mobility of the cervical spines. Conclusion: Little change occurs at the translational motion under the maximum flexion and extension position,yet greater the angular variation occurs C3-4,C4-5 and C5-6 by the three positions.There are significant contributions of the C4-5,C5-6 and C6-7 to total angular mobility of the cervical spine.