Spiral structure design of a vascular interventional robot based on fluid-structure interaction

Abstract The spiral structure of interventional robots is widely utilized for vascular dredging procedures. Variations in the spiral structural parameters of these robots exert a significant impact on the hemodynamic parameters within the vessel during the interventional process; therefore, optimizing the design of these parameters constitutes a crucial prerequisite for ensuring safe diagnosis and treatment. Based on the bidirectional fluid-structure interaction (FSI) between pulsatile blood and elastic blood vessels, theoretical calculations and experimental measurements of the fluid velocity inside the vessel during robotic intervention were conducted. The results demonstrate that the trends and magnitudes of the calculated values are essentially consistent with those of the measured values. Furthermore, the range and variance methods in orthogonal design were applied to numerically investigate the effects of three key spiral parameters – spiral pitch, spiral groove depth, and thread profile – on hemodynamic and vascular parameters, including blood velocity, blood pressure, vascular wall shear stress, and vessel deformation. The findings indicate that spiral groove depth is the primary and most significant factor influencing blood velocity, blood pressure, and vessel deformation. In contrast, spiral pitch emerged as the main and critical factor affecting vascular wall shear stress. Meanwhile, thread profile is found to be a secondary factor with relatively minor impacts on all the aforementioned parameters. To achieve the objective of safe interventional diagnosis and treatment, it is recommended that the robot’s spiral structure be designed with a smaller spiral groove depth, a moderate spiral pitch, and a thread profile featuring strong cutting capability.