Wearable 3D-Printed Thumb-Shaped Device Based on Fiber Bragg Grating Sensor for Epidural Space Detection

Fiber Bragg grating sensors (FBGs) are increasingly popular in various biomedical fields due to their undeniable benefits, hardly found in other sensing technologies. To overcome FBGs' inherent fragility, encapsulation in other hosting materials, such as silicone rubber or resins, has been widely practiced. This approach allowed for high flexibility and adaptability of the developed devices but can be time-consuming and labor-intensive. Fused deposition modeling (FDM) has recently been proposed to develop 3D-printed devices embedding FBGs, enabling the deployment of systems with high repeatability, accuracy, and fast fabrication time. The exploitation of 3D-printed device based on FBG for biomedical applications is still little explored in the literature. In this article, we proposed an application never yet investigated to assist physicians in performing epidural procedures. Accurately detecting the epidural space (ES) in these treatments is highly challenging as it relies on the clinician's perception. Moreover, due to ES small size, the risk of failure is common in clinical practice. In this field, state-of-the-art solutions have been devised to instrument the generally used needle or the syringe plunger. These solutions can obstruct the drug delivery inside the needle or contaminate the sterile field. In this study, we propose a 3D-printed thumb-shaped device embedding a single FBG conceived to be worn under a clinician's glove, thus overcoming the limitations associated with the existing systems. Design, fabrication, and metrological characterization of the proposed system are reported. Furthermore, a feasibility assessment in a real clinical scenario demonstrated its ability to detect the ES correctly.