基于流固耦合有限元模型评估颈椎旋转手法下颈动脉粥样硬化斑块的破裂风险

Risk Assessment of Carotid Atherosclerotic Plaque Rupture under Cervical Rotatory Manipulation Based on Fluid-Structure Interaction Finite Element Model

目的评估颈椎旋转手法对颈动脉粥样硬化斑块的破裂风险。方法建立颈动脉粥样硬化斑块流固耦合(fluid-structure interaction,FSI)模型。采用FSI模型模拟颈椎旋转手法对颈动脉斑块和管腔的拉伸形变。记录斑块和管腔的血流最大剪切力(flow shear stress,FSS)、最大壁面切应力(wall shear stress,WSS)、最大斑块壁应力(plaque wall stress,PWS)、壁面拉应力(wall tensile stress,WTS)和壁面压强(wall pressure,WP)等力学参数。结果在颈动脉16%拉伸形变下,斑块最大WSS为40.54 Pa,此处斑块可能表皮损伤;最大PWS为66.16 kPa,远小于斑块破裂阈值;内部纤维帽最大WTS和最大应变分别为156.75 kPa和0.56,大于破裂应变范围,能达到断裂临界值;管腔最大WTS为1040.30 kPa,已接近中膜破裂阈值,可能会引起血管损伤。结论颈椎旋转至生理极限位后,颈动脉拉伸可能造成斑块表皮组织破坏导致脱落,斑块内部会形成损伤、溃疡和出血以及血管损伤,影响斑块稳定性。在颈动脉粥样硬化斑块的颈部疾病患者中应谨慎进行颈椎旋转手法治疗,手法前对斑块进行FSI评估可能是一种有效的安全性筛查方法。

Objective To evaluate the rupture risk of carotid atherosclerotic plaque under cervical rotatory manipulation.Methods The fluid-structure interaction(FSI)model of carotid atherosclerotic plaque was established,and tensile deformation of the plaque and lumen under cervical rotatory manipulation was simulated.Mechanical parameters such as the maximum flow shear stress(FSS),the maximum wall shear stress(WSS),the maximum plaque wall stress(PWS),wall tensile stress(WTS)and wall pressure(WP)of the plaque and lumen were recorded.Results Under 16%carotid tensile deformation,the maximum WSS of the plaque was 40.54 Pa.The maximum PWS was 66.16 kPa,which was far smaller than the threshold of plaque rupture.The maximum WTS of fiber cap and the maximum strain were 156.75 kPa and 0.56,which were larger than the fracture strain range.The maximum WTS of the lumen was 1040.30 kPa,which approached the threshold of medial membrane rupture and might cause vascular injury.Conclusions When the cervical spine rotates to the end range of motion,large carotid artery stretch may cause damage to epidermal tissues of the plaque,leading to abscission.Lesions,ulcers,bleeding and vascular damage may form inside the plaque,which will affect stability of the plaque.Cervical rotatory manipulation should be performed cautiously in patients with cervical diseases who also have carotid atherosclerotic plaques.The finite element assessment of plaques before manipulation may be an effective safety screening method.