Design and fabrication of a non-invasive, wireless system for monitoring needle insertion during epidural puncture

Over the last decades epidural analgesia has gathered research interest and broad clinical acceptance. In this procedure, the detection of the epidural space is pivotal to avoid major complications. Although, some systems for supporting the anaesthetist in the epidural space detection are commercially available, this difficult procedure is often performed without any support. In previous articles, our research group described a new approach for a non-invasive detection of the epidural space; the assessment of the system was also performed both on a spinal column simulator and in ex vivo animal model (small pig). The mentioned system is based on a Force Sensing Resistor (FSR) that monitors the load exerted by the anaesthesiologist on the syringe plunger during the procedure. The resistance of the sensor is transduced into a voltage by means of a Wheatstone bridge (WB), then it is amplified, finally it is collected by a remote laptop. When the needle reaches the epidural space, the load applied by the anaesthesiologist decreases, so the consequent change of the system output may be used for the detection of the entrance within this space. The previous version of the system communicates to the laptop via USB. In this article, we described a new version of the system which communicates to the laptop via wireless. This solution aims at facilitating the use of the system in clinical settings. After the description of the measuring system, its preliminary assessment in patients undergoing epidural puncture will be reported.