Optical fiber technology enables smart needles for epidurals: an in-vivo swine study.

Benito Carotenuto,Alberto Micco,Andrea Cusano,Ezio Amorizzo,Armando Ricciardi,Antonello Cutolo,Marco Mercieri

doi:10.1364/boe.10.001351

Abstract

Nowadays, epidural space identification is made by using subjective and manual techniques characterized by failure rates up to 7%. In this work, we propose a fiber optic sensor technology based needle guidance system, that is directly inspired by the most common technique currently used for epidurals; through real-time strain measurements, the fiber Bragg grating integrated inside the needle lumen is able to effectively perceive the typical force drop occurring when the needle enters the epidural space. An in vivo swine study demonstrates the validity of our approach, paving the way for the development of lab-in-a-needle systems.

Highlights

Epidural anesthesia (EA) is the most common loco-regional anesthesia practice used for labor, postoperative and chronic pain treatment [1]
Note that the signal variation registered between 3 and 15 seconds in Fig. 3(a) is not due to any temperature effect, but it is related to the fact that, after perceiving the drop, the clinician released the grip on the needle and stopped applying a pulling force
Thanks to the catheter sensorization, by monitoring the intensity of the fiber Bragg grating (FBG) back-reflected signal, it could be possible to detect and prevent catheter bending events which are the major cause of failed epidurals [29]. In this in vivo swine study, we have evaluated the performances of a needle guidance system for EA

Summary

Introduction

Epidural anesthesia (EA) is the most common loco-regional anesthesia practice used for labor, postoperative and chronic pain treatment [1]. The medical procedure for EA consists in inserting a needle into the skin and directing it towards the epidural space (ES) where the anesthetic is injected. The ES is located in the spine, between the ligament flavum and the dura. The correct placement of the needle tip into ES is determined by exploiting 'manual techniques', including the most common Loss of Resistance (LOR). LOR technique consists in advancing the needle by applying constant or intermittent pressures to a specific syringe plunger. Once the needle crosses the ligament flavum (which is a hard tissue), an abrupt resistance drop on the plunger is perceived. LOR is a ‘blind’ technique and the success of this procedure depends on the expertise of the operator. Accurate imaging procedures such as fluoroscopy or CT are often used in Pain Medicine, their use in routine clinical anesthesia is unpractical and expensive

Methods

Results

Discussion

Conclusion