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
Abstract@#The prevalence of overweight and obesity among children in China has entered a new phase of pandemic, with substantial regional differences. There are diverse and complex determinants for overweight and obesity in school age children, it is necessary to take targeted measures towards children of different ages and regions, comprehensively consider the effects of physiological, social, household and behavioral factors and simultaneously strengthen connections between schools, medical institutions and families, so as to actively respond to the severe situation of childhood obesity epidemic.
ABSTRACT
Objective To analyze the influence of ligaments surrounding sacroiliac joints (SIJs) on stability of SIJs by finite element method. Methods The finite element lumbar spine-pelvis-femur model was established. Based on this normal model, all SIJ ligaments in both sides were removed in turn, to establish models without iliolumbar ligaments, sacroiliac anterior ligaments, sacroiliac posterior ligament, sacrotuberous ligaments, sacrospinous ligaments, sacroiliac interosseous ligaments, respectively. The models were used to simulate physiological motions of the spine. The range of motion (ROM) and average stress on the left and right SIJs were analyzed and compared with the normal models. Results Compared with the normal SIJ model, no significant differences in the ROM of bilateral SIJs were found in the models without sacrotuberous ligaments, sacrospinous ligaments and sacroiliac posterior ligaments; for the model without acroiliacinterosseous ligaments, there was no significant difference in the ROM of the left SIJs under spinal right rotation and ROM of the right SIJs under spinal extension, but the ROM of bilateral SIJs increased significantly under the other spinal physiological activities. Under the physiological activities of the spine, the average stress of the SIJ surface in the left and right sides of the model without acroiliacinterosseous ligaments significantly decreased. Conclusions Of all the sacroiliac ligaments, the sacroiliac interosseous ligaments showed the maximum influences on the stability of SIJs. The research findings are helpful to investigate the mechanism of SIJ subluxation and provide certain theoretical basis for clinical treatment of SIJ subluxation.