Multi-axis mechanical simulator for epidural needle insertion

Abstract

Physical Sciences Inc. and Clinicians at the Beth Israel-Deaconess Medical Center have developed a novel simulator for training clinicians to insert epidural anesthesia needles. The simulator uses cables to apply forces to a needle to simulate tissue elastic and viscous properties. Cable tension is applied by brushless motors. Measurements of the motor shaft angle are used to measure cable payout and hence needle position. The controller simulates tissue properties rather than directly controlling forces. The arrangement allows for out-of-plane needle motion and can be programmed to allow trainees to make errors in placing the needle, and they will receive the appropriate haptic sensations. The simulator incorporates physical anatomical models for palpation and provides a syringe loss-of-resistance feature to simulate entry into the epidural space. This paper describes the mechanical design of the device and shows how the software algorithm simulates tissue elastic and viscous-drag properties. Initial test results are presented. © Springer-Verlag 2004.