False Loss of Resistance in Cervical Epidural Injection: The Loss of Resistance Technique Compared with the Epidrum Guidance in Locating Epidural Space

Abstract

Background: Epidural block failures can occur due to a misleading loss of resistance (LOR) signal. Objective: This study was designed to evaluate the false LOR rate and to determine whether the Epidrum, which is an LOR device for identifying the epidural space, improves the ability to find the epidural space during cervical epidural injection compared the LOR technique. Study Design: A randomized, single-blind trial. Setting: Single academic medical center. Methods: A total of 150 patients undergoing cervical interlaminar epidural injections at C7-T1 were randomized to receive either the LOR technique with a syringe (group C) or the Epidrum guidance (group E). Fluoroscopic images were used to confirm the accuracy of the needle placement within the epidural space. The rate of misleading epidural signals and adverse effects were recorded and analyzed. Results: The false LOR rate was 74.7% for group C, 62.7% for group E, and 68.7% overall. The incidence of false LOR was not significantly different between the 2 groups. Also, the success rate and the rate of true epidural signals were similar between the 2 groups. Limitations: The Epidrum cannot be used to confirm whether the needle has entered the vascular space without fluoroscopy. Conclusions: In this study, we did not find any difference in accuracy between the Epidrum and the LOR technique with a syringe for detecting the cervical epidural space. The overall higher false LOR rate suggests that the combined use of fluoroscopy and LOR technique with a syringe or the Epidrum is necessary to increase the rate of finding the true cervical epidural space. Clinical Trials registration: KCT0001333 Key words: Cervical epidural injection, epidural space, Epidrum, false positive, false negative, loss of resistance