目的:由颈部区域的重复性工作或劳损引起的肌肉功能障碍可干扰肌肉反应。肌肉功能障碍可能是引起颈椎病的重要因素。然而,当枕下肌群出现功能障碍时,上颈椎的生物力学特性如何改变还没有研究。本研究的目的是利用有限元(FE)方法研究颈椎病的生物力学证据,从而为临床医生进行穴位治疗提供指导。
方法:通过改变枕下肌的弹性模量,在正常肌肉功能和肌肉功能障碍的条件下重建C0-C3运动段的四个FE模型。对于两个正常条件下的有限元模型,在一个肌肉功能障碍FE模型中,C0-C3运动节段两侧的枕下肌肉的弹性模量相等且在正常范围内,两侧的弹性模量相等且大于37kPa,代表肌肉高张力;另一方面,左右枕下肌的弹性模量不同,表明肌肉不平衡。外侧寰枢关节(LAAJ)的生物力学行为,寰齿突关节(ADJ),通过模拟分析椎间盘(IVD),在六次屈曲载荷下进行,扩展,左右横向弯曲,左右轴向旋转。
结果:在屈曲下,肌肉失衡的LAAJ最大应力高于正常肌肉和高张力,而高渗模型中IVD的最大应力高于正常模型和不平衡模型。在所有模型的所有载荷中,ADJ中的最大应力在延伸下最大。肌肉失衡和高张力不会引起ADJ的过度应激和应激分布异常。
结论:肌肉功能障碍增加了LAAJ和IVD的压力,但不影响ADJ.
OBJECTIVE: Muscle dysfunction caused by repetitive work or strain in the neck region can interfere muscle responses. Muscle dysfunction can be an important factor in causing cervical spondylosis. However, there has been no research on how the biomechanical properties of the upper cervical spine change when the suboccipital muscle group experiences dysfunction. The objective of this study was to investigate the biomechanical evidence for cervical spondylosis by utilizing the finite element (FE) approach, thus and to provide guidance for clinicians performing acupoint therapy.
METHODS: By varying the elastic modulus of the suboccipital muscle, the four FE models of C0-C3 motion segments were reconstructed under the conditions of normal muscle function and muscle dysfunction. For the two normal condition FE models, the elastic modulus for suboccipital muscles on both sides of the C0-C3 motion segments was equal and within the normal range In one muscle dysfunction FE model, the elastic modulus on both sides was equal and greater than 37 kPa, which represented muscle hypertonia; in the other, the elastic modulus of the left and right suboccipital muscles was different, indicating muscle imbalance. The biomechanical behavior of the lateral atlantoaxial joint (LAAJ), atlanto-odontoid joint (ADJ), and intervertebral disc (IVD) was analyzed by simulations, which were carried out under the six loadings of flexion, extension, left and right lateral bending, left and right axial rotation.
RESULTS: Under flexion, the maximum stress in LAAJ with muscle imbalance was higher than that with normal muscle and hypertonia, while the maximum stress in IVD in the hypertonic model was higher than that in the normal and imbalance models. The maximum stress in ADJ was the largest under extension among all loadings for all models. Muscle imbalance and hypertonia did not cause overstress and stress distribution abnormalities in ADJ.
CONCLUSIONS: Muscle dysfunction increases the stress in LAAJ and in IVD, but it does not affect ADJ.