FBG-based system for loss of resistance detection during epidural injections

Epidural injection represents a widely accepted clinical practice in the management of pain relief caused by musculoskeletal disorders, labour and during surgery. The main purpose of this technique is to mitigate the painful feeling in the affected area by injecting anaesthetics and analgesics in the epidural space (the area between the ligamentum flavum and the dura mater). Correct epidural space detection is still challenging because of the small size, and the failure rate is not negligible. Including the existing techniques employed for identifying the epidural space, loss of resistance (LOR) is the most popular method used in clinical practice. It is based on the LOR feeling experienced by the anesthesiologist when the Tuohy needle moves from the ligamentum flavum to the epidural space due to the different density of these two tissues. In the last decades, several systems have been developed to support clinicians during the procedure. Recently, fiber Bragg grating sensors (FBG) have shown promising results for developing techniques able to detect the LOR. In this study, we proposed a novel FBG-based system for LOR detection during epidural puncture. We instrumented the syringe plunger with a flexible polymeric matrix. To assess its performance in LOR detection, we enrolled five users who performed the epidural procedure using a commercial simulator. The results obtained showed the ability of our system to detect LOR.