脊髓型颈椎病患者三维有限元模型的构建与生物力学分析

目的：构建颈部三维有限元模型(finite element model，FEM)，初步分析脊髓型颈椎病(cervical spondylotic myelopathy，CSM)患者与对照者颈部生物力学的差异，为CSM发病机制的研究提供生物力学依据。方法：以1名CSM患者作为力学模拟实验对象进行三维CT扫描，并构建颈部三维FEM依照患者的年龄、性别、身高、体重等参数选取本团队已有的健康颈部三维FEM作为对照，比较患者和对照者在颈椎正常受力情况下椎体、椎间盘、韧带及脊髓的应力差异，以及后仰伸运动后最大应力的差异。结果：成功构建CSM患者及对照者FEM模型，并进行力学分析，CSM患者颈椎椎体受力差异C5~C6节段最明显，对照者和患者的最大应力部位均在椎体前缘，CSM患者椎体前缘的最大应力小于对照者；CSM患者椎间盘应力分布不均匀，最大应力部位集中在椎间盘底部后缘的两侧；CSM患者各韧带的应力分布不均匀，其中后纵韧带应力最大。CSM患者颈椎在后仰伸运动时范围受限。结论：CSM患者相对于对照者可能存在颈部椎体、椎间盘及韧带受力平衡的改变和颈椎运动范围的受限，这可能与CSM力学发病机制相关。

Construction of three-dimensional finite element model and biomechanical study on patient with with cervical spondylotic myelopathy

Objective: To establish a three-dimensional finite element model (FEM) of the neck, to analyze the differences in neck biomechanics between patient with cervical spondylotic myelopathy (CSM) and healthy subject and to provide biomechanics basis for the pathogenesis of CSM. Methods: A patient with CSM was enrolled in a mechanical simulation experiment. Three-dimensional CT scan was performed, and three-dimensional FEM of the neck was constructed. A heathy subject was selected as a control according to the patient’s age, gender, height, and weight. Three-dimensional FEM was used to compare the stress differences in the vertebral body, intervertebral disc, ligament and spinal cord under the normal stress of the cervical spine and the maximum stress of the posterior reclining motion. Results: Successfully constructed FEM model of CSM patient and control, and performed mechanical analysis, the most obvious difference in cervical vertebral body force was at C5–C6 segment in CSM patients. The maximum stress site of control and patient was at the anterior edge of the vertebral body. The maximum stress of the vertebral body in the CSM patient was less than that of the control. The stress distribution of the intervertebral disc was irregular in the CSM patient, and the maximum stress was concentrated on both sides of the posterior edge of the intervertebral disc. The stress distribution of the ligaments of the CSM patient was uneven. The maximum stress was in the posterior longitudinal ligament. The range of neck movement in extension of the CSM patient was restricted. Conclusion: Compared with the healthy subject, the balance of the vertebral body, intervertebral disc, ligament and limited range of motion of the CSM patient has been changed, which may be related to the mechanical pathogenesis of cervical spondylotic myelopathy.