应用三维非接触式光学应变检测技术动态分析颈椎屈曲过程中椎管形态变化及椎间盘应变

Dynamic analysis of cervical spinal canal morphological changes and intervertebral disc strain during cervical flexion using three-dimensional non-contact optical strain detection technique

中文关键词:  颈椎椎管狭窄  数字图像相关技术  椎管形态  椎间盘应变  黄韧带拉伸程度

英文关键词:Cervical spinal stenosis  Digital image correlation(DIC) technique  Spinal canal morphology  Intervertebral disc strain  Ligamentum flavum stretching

中文摘要:

  【摘要】 目的：定量评估颈椎前屈过程中椎管矢状径、椎间盘应变及黄韧带拉伸变化规律，为颈椎椎管狭窄（cervical spinal stenosis，CSS）的非手术治疗方案提供参考。方法：选取6具成人新鲜冰冻颈椎标本（C0-T1，年龄45.7±10.3岁），沿正中矢状面切开，显露椎管结构。利用自主设计的弧形夹具对标本进行动态屈曲运动加载（从后伸15°~前屈45°，间隔5°），通过三维数字图像相关（digital image correlation，DIC）系统非接触式采集各运动状态下椎间盘应变（E）（前、中、后为分别记E1、E2、E3）、椎管矢状径变化量（D）以及黄韧带拉伸程度（L）。利用线性回归分析上述指标与前屈角度、颈椎节段的关系。结果：（1）随着前屈角度的增加，各颈椎节段的E、D和L均逐渐增大。（2）在C2/3、C3/4、C4/5、C5/6、C6/7节段，E1、E2、E3与前屈角度呈线性正相关（P<0.05）；在C2/C3、C3/4、C4/5、C5/6节段，D与前屈角度呈线性正相关（P<0.05）；在C3/4、C4/5、C5/6、C6/C7节段，L与前屈角度呈线性正相关（P<0.05）。（3）后伸10°，随着颈椎节段下移，E2、E3、L逐渐增大（P<0.05）；后伸5°，随着颈椎节段下移，E2、E3、D、L逐渐增大（P<0.05）；中立位，随着颈椎节段下移，E1、E2、E3、D、L逐渐增大（P<0.05）；前屈5°、10°，随着颈椎节段下移，E3、D、L逐渐增大（P<0.05）；前屈15°，随着颈椎节段下移，D、L逐渐增大（P<0.05）；前屈20°、25°、30°、35°、40°、45°，随着颈椎节段下移，L逐渐增大（P<0.05）。（4）随着前屈角度的增加，C2/3、C3/4、C4/5和C5/6节段观察到D与L之间存在显著性正相关。结论：DIC技术可实现颈椎连续屈伸过程中椎管形态及相关结构的同步动态观测。颈椎从后伸至前屈过程中，椎管矢状径逐渐扩大，黄韧带牵张及椎间盘后方应变增加。

英文摘要:

  【Abstract】 Objectives: To quantitatively evaluate the patterns of changes in spinal canal sagittal diameter, intervertebral disc(IVD) strain and ligamentum flavum stretching during cervical flexion motion, and to provide a reference for the non-surgical treatment strategies for cervical spinal stenosis(CSS). Methods: Six fresh-frozen adult cervical spine specimens(C0-T1, mean age 45.7±10.3 years) were sectioned along the mid-sagittal plane to expose the spinal canal structures. Specimens were loaded with dynamic buckling motion(from 15° extension to 45° flexion, with 5° intervals) using a custom-designed arc-shaped fixture. The digital image correlation(DIC) system was adopted to capture in a non-contact way the IVD strain(E)(with anterior, middle, and posterior regions denoted as E1, E2, and E3, respectively), spinal canal sagittal diameter change(D), and ligamentum flavum stretching degree(L). Linear regression analysis was performed to examine relationships between these parameters and flexion angles as well as cervical segments. Results: (1)With increasing flexion angle, progressive increases in E, D, and L were observed across all cervical segments. (2) At C2/3, C3/4, C4/5, C5/6, and C6/7 segments, E1, E2 and E3 showed significant linear positive correlations with flexion angle(P<0.05); At C2/3, C3/4, C4/5, and C5/6 segments, D demonstrated linear positive correlation with flexion angle(P<0.05); At C3/4, C4/5, C5/6, and C6/7 segments, L showed linear positive correlation with flexion angle. (3) At 10° extension, E2, E3, and L progressively increased with descending cervical segments(P<0.05); At extension 5°, E2, E3, D, and L progressively increased with descending cervical segments(P<0.05); In neutral position, E1, E2, E3, D, and L progressively increased with descending cervical segments(P<0.05); At 5° and 10° flexion, E3, D, and L progressively increased with descending cervical levels(P<0.05); At 15° flexion, D and L progressively increased with descending cervical segments(P<0.05); At 20°, 25°, 30°, 35°, 40°, and 45° flexion, L progressively increased with descending cervical segments(P<0.05). (4) With increasing flexion angle, significant positive correlations between D and L were observed at C2/3, C3/4, C4/5, and C5/6 segments(P<0.05). Conclusions: DIC technique enables synchronous dynamic observation of cervical spinal canal morphology and related structures during continuous flexion-extension motion of the cervical spine. From extension to flexion, the sagittal diameter of the spinal canal gradually increases, accompanied by marked inereases in ligamentum flavum tension and posterior IVD strain.