ABSTRACT
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 1 040.30 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.
ABSTRACT
BACKGROUND: Cervical rotation manipulation is a non-surgical method of cervical spondylosis, showing significant treatment efficacy. But the safety for patients with carotid artery atherosclerosis remains obscure. OBJECTIVE: To analyze the hemodynamic changes of atherosclerotic carotid arteries treated by cervical rotatory manipulation, and to explore the effect of cervical rotatory manipulation on the hemodynamics of atherosclerotic plaque. METHODS: Eight cases of stenosis of ramification of the carotid artery with plaque on MRI. The hemodynamic model of carotid artery atherosclerosis was established, assigned with general boundary conditions and simulated the cervical stretch during cervical rotatory manipulation. All models were grouped and stretched into 0％ (control group), 7％ and 16％ stretch to simulate the hemodynamic changes of atherosclerotic plaque. The hemodynamic parameters, including average wall shear stress, the maximum wall shear stress, the average maximum wall shear stress, the blood velocity of the plaque, and blood flow vectorgraph were compared among groups. RESULTS AND CONCLUSION: (1) All hemodynamic parameters had no significant differences between 7％ stretch and control groups (P＞ 0.05). Compared with the control group, the wall shear stress, the maximum wall shear stress, and the maximum wall shear stress in the 16％ stretch group were significantly increased (P ＜ 0.05), and other indexes showed no significant differences. (2) In summary, different stretches by cervical rotatory manipulation possess different effects on plaque, and a 16％ stretch may affect the hemodynamics of plaque.