Fluid-structure interaction analysis on hemodynamics of vertebral arteries during physiological activities of cervical spine / 医用生物力学

ABSTRACT

Objective To further understand the biomechanical relationship between activities of cervical spine and blood flow of vertebral artery (VA) by developing the VA finite element model and calculating the fluid-structure interaction. Methods Based on the normal model of cervical spine and the developed C0-T1 finite element model with bilateral VA, the flexion and extension, right and left lateral bending, right and left axial rotation movement of cervical spine at physiological velocity were simulated. The effects of cervical activities on stress of vertebral arterial wall were observed, and the biomechanical interaction between the vessel wall and fluid was calculated by fluid-structure interaction equation to obtain the hemodynamic parameters. Results The maximum stress was usually concentrated on the both sides of C2 transverse foramen, where the second arc of vertebral arterial wall protruded into the cranial direction during cervical activities. The maximum strain of the vessel wall was most obvious during the extension and lateral bending movement, with strain ratio of 23.04% and 35.5%, respectively. The maximum stress on the vessel was located in the position of contralateral transverse foramen during lateral bending movement, while the maximum strain on the vessel was located in the position of ipsilateral transverse foramen during rotation movement. In aspect of cervical spine range of motion (ROM), the minimum volume flow rate occurred within 30%-40% of the physiological ROM. The volume flow rate-time curve of bilateral VA was similar during flexion and extension movement, when the circulation of flow rate was completed for two times within 0.5 s. The peak and valley of ipsilateral blood flow in volume flow rate-time curve occurred earlier than that of contralateral blood flow during lateral bending movement, while the results of rotation movement were opposite. Conclusions The obtained stress features of bilateral VA vessel and the law of the volume flow rate-time curve validated the experimental results with those in the literature, which could reasonably explain the clinical phenomenon. The established model would provide an ideal platform for researches on vertebral artery-related diseases.