| description abstract | Abstract. Robotic-assisted lumbar puncture (LP) has demonstrated significant advantages over manual procedures in terms of accuracy and repeatability, with robotic-assisted needle insertion devices (RNIDs) serving as the core component for accurate needle placement. However, current RNIDs still encounter critical limitations in needle tip deflection and complex construction. The patient-specific design, based on preoperative imaging and tissue mechanical properties, may potentially improve the aforementioned issues. This article proposes a one-degree-of-freedom (1-DOF) patient-specific RNID to enhance the insertion accuracy. The 1-DOF motion coupling both insertion and rotation is achieved through a replaceable helical-type inner liner bush (RHILB), which functions as the RNID’s core transmission component. The RHILB features a patient-specific insertion-rotation ratio (IRR) determined from preoperative X-ray imaging. Utilizing three-dimensional (3D) printing technology, these customized RHILBs can be rapidly manufactured and seamlessly integrated into the RNID via a plug-and-play interface, enabling quick replacement for different patients. The preliminary experiments are conducted first to demonstrate the optimal IRRs for different materials. The kinematic model of the core component, i.e., the RHILB, is established. A fifth-order transition curve equation is formulated to eliminate impacts on velocity and acceleration during insertion. Prototype experiments are conducted to evaluate the insertion accuracy and patient-specific issues. Comparative results show that the variable-IRR design reduces mean needle tip deflection by 27.73% (p<0.05) and 62.40% (p<0.001) than the constant IRR design. | |
