Bevel-Tip Needle Deflection Modeling, Simulation, and Validation in Multi-Layer Tissues.

Percutaneous needle insertions are commonly performed for diagnostic and therapeutic purposes as an effective alternative to more invasive surgical procedures. However, the outcome of needle-based approaches relies heavily on the accuracy of needle placement, which remains a challenge even with robot assistance and medical imaging guidance due to needle deflection caused by contact with soft tissues. In this paper, we present a novel mechanics-based 2D bevel-tip needle model that can account for the effect of nonlinear strain-dependent behavior of biological soft tissues under compression.

EVALUATION OF NEEDLE DRIVER DESIGNS FOR ROBOT-ASSISTED NEEDLE INSERTIONS UNDER MRI GUIDANCE.

This paper presents the evaluation of two detachable MR-Conditional needle driver designs for our 4-degree-of-freedom (DOF) robotic platform for MRI-guided spinal injections. Compared to their predecessor, the new designs open up the possibility of intraoperative needle driver attachment, and in order to evaluate the feasibility of such an approach, force and torque requried during the needle driver attachment process are captured to evaluate which of the two designs are better suited for such purpose. A simulated clinical scenario is also carried out to measure the possible position change of the 4-DOF robot with respect to the patient due to intraoperative tool attachment, thus providing future guidance to the proposed clinical workflow in the framework of body-mounted robotic surgical devices.

An MR-Conditional Needle Driver for Robot-Assisted Spinal Injections: Design Modifications and Evaluations.

This paper introduces design modifications to our MR-Conditional, 2-degree-of-freedom (DOF), remotely-actuated needle driver for MRI-guided spinal injections. The new needle driver should better meet cleaning and sterilization guidelines needed for regulatory approval, preserve the sterile field during intraoperative needle attachment, and offer better ergonomics and intuitiveness when handling the device. Dy-namic and static force and torque required to properly install the needle driver onto our 4-DOF robot base are analyzed, which provide insight into the risks of intraoperative tool attachment in the setting of robot-assisted spinal injections under MRI guidance.