A 3D-Printed Needle Driver Based on Auxetic Structure and Inchworm Kinematics

Abstract

Linear actuation is a basic need in robotized manipulation of surgical instruments, that must comply with a challenging environment in terms of safety, compactness and now often compatibility with imaging modalities like CT or MRI. In this paper, we focus on needle manipulation for interventional radiology. We propose a needle driver, i.e. a linear actuator for needle insertion, based on the inchworm principle combined with pneumatic energy. Our first contribution is to propose, model and implement the device using a so-called auxetic structure. Its use increases achievable displacement under pressure and provides sufficient off-axis stiffness to use the actuator without additional guidance. Simplified modeling is introduced for the actuator synthesis. Our second contribution is to implement the actuator with multimaterial additive manufacturing combining rigid and flexible materials to increase compactness. As a third contribution, initial assessment of component sterilization and compatibility with X-ray and MRI imaging modalities is presented.

Development of models for additively manufactured actuators using compliant Wren mechanism

“…Space in the imaging device is very limited. Step by step motion as performed in [13] is therefore selected.…”

“…We then desire to have a pneumatic chamber to develop forces for the needle translation and rotation. Following [13], the operating pressure is set to 3 bars, and intended displacement and rotation are equal to 2 mm and approximately 5 • . In soft tissues such as liver or kidney, the needle is in interaction with tissues of very low stiffness and the insertion forces are low [19], so they are neglected during analysis.…”

“…The implementation can be conducted either for small stroke by simply using a chamber reinforced by a compliant Wren mechanism (CWM), or by integrating the device in a step by step system [10,11]. In biomedical context, design of compliant actuators for needle manipulation using such 1 10 mm an approach is of interest [12,13]. This is our application context in the paper (Fig.…”

Cellular Auxetic Structures for Mechanical Metamaterials: A Review

“…Hasse et al made use of an auxetic re-entrant structure and proposed a tube-like bending actuator where a difference in pressure between the internal and external surfaces of the tube could generate circumferential actuation [145]. A pneumatic 3D printed needle driver which facilitates linear actuation in surgical instruments was proposed by Pfeil et al [146]. The driver used a re-entrant auxetic structure and was able to move and guide a needle due to the combined effects of pneumatics, inchworm kinematics and multimaterial additive manufacturing.…”

Hydraulically-actuated compliant revolute joint for medical robotic systems based on multimaterial additive manufacturing

“…Range of motion and lifetime are adapted to medical robots of limited number of uses. It was in addition recently shown that the materials could also endure gamma sterilization [18]. Our second contribution is thus the design of a transformation mechanism in the HSC joint to finally get a hydraulically-actuated revolute joint.…”