Incidence of intravascular penetration in transforaminal lumbosacral epidural steroid injections

Study Design. A prospective, observational, human in vivo study. Objectives. To evaluate the incidence of vascular penetration during fluoro scopically guided, contrast-enhanced, transforaminal lumbar epidural steroi d injections (ESIs) and determine whether a "flash" (blood in the needle hu b) or aspiration of blood can be used to predict a vascular injection. Summary of Background Data. Incorrectly placed, intravascular lumbosacral s pinel injections result in systemic medication flow that misses the desired target No previous studies evaluate the incidence of vascular injections i n transforaminal ESIs, nor the ability of flash to predict a vascular injec tion. Methods. The incidence of flesh or positive blood aspiration and the incide nce of fluoroscopically confirmed vascular spread were prospectively observ ed in 670 patients treated with lumbosacral fluoroscopically guided transfo raminal ESIs. Presence Of a flash or positive aspiration was documented. Co ntrast was injected to determine whether the needle tip was intravascular. Results. Seven hundred sixty-one transforaminal ESIs were included. The ove rall rate of intravascular injections was 11.2%. There was a statistically significant higher rate of intravascular injections (21.3%) noted with tran sforaminal ESIs performed at S1 (n = 178), compared with those at the lumba r levels (8.1%, n = 583). Using flash or positive blood aspirate to predict intravascular injections was 97.9% specific, hut-only 44.7% sensitive. Conclusions. There is a high incidence of intravascular injections in trans foraminal ESIs that is significantly Increased at S1. Using a flash or bloo d aspiration to predict an intravascular injection is not sensitive, and th erefore a negative flash or aspiration is not reliable. Fluoroscopically gu ided procedures without contrast confirmation are instilling medications in travascularly and therefore not into the desired epidural location. This fi nding confirms the need for not only fluoroscopic guidance: but also contra st injection instillation in lumbosacral transforaminal ESIs.