不同牵拉方式对腰椎的生物力学影响

目的 采用三维有限元方法研究不同牵拉条件对腰椎生物力学的影响。方法 通过对腰椎L1~5节段扫描，获得CT图像导入Mimics三维重建获得腰椎L1~5的三维几何模型，利用Geomagic Studio和Hypermesh获得腰椎L1~5的网格模型。运用Abaqus进行不同牵拉条件下的腰椎有限元仿真计算。结果 头低位角度与髓核内应力有相关性，头低位角度不超过10°时，髓核内应力随摆动周期规律性变化；头低位角度大于10°时，应力呈降低趋势。摆动模式下，纤维环内环应力增加，促进椎间盘回缩。结论 牵拉治疗有助于缓解腰椎疼痛，摆动作用有助于协调牵拉作用在各方向的效果，牵拉方式结合摆动可更好地梳理和解除后部小关节紊乱。此外，患者在治疗中应选取适当的牵拉作用力以达到良好的治疗效果。

Biomechanical effects of different traction modes on lumbar spine

Objective To study biomechanical effects of the lumbar spine under different traction conditions by using three-dimensional (3D) finite element method. Methods The CT images of lumbar segment L1-5 were input to the Mimics 10.01 for developing 3D geometrical model of L1-5. Then the mesh model of L1-5 was obtained using Geomagic Studio 12.0 and Hypermesh 11.0. The finite element simulation of the lumbar spine under different traction conditions was made by using Abaqus. Results Head-down titling angle was related to the nucleus pulposus stress. When the head-down tilting angle was smaller than 10°, the nucleus pulposus stress regularly changed with the swing cycle; while the head-down tilting angle exceeded 10°, the stress was decreased. In the swing mode, the annulus inner ring stress was increased to promote intervertebral retraction. Conclusions The traction mode helps to relieve the lumbar pain with the swing helping to coordinate the traction effect in each direction, which can better sort out and relieve the rear facet joint disorders. In addition, patients should be careful to select the appropriate traction force in the treatment to achieve good therapeutic effect.