Incidence of intravascular penetration in transforaminal lumbosacral epidural steroid injections. (KDV Orthopedics and Rehabilitation, York, PA) Spine 2000;25:2628–2632.
Authors: Furmen Michael B. , O'Brien Erin M. , Zgleszewski: Timothy M. 
Published: March 2003

A prospective, observational, human, in vivo study was used to evaluate the incidence of vascular penetration during fluoroscopically guided, contrast‐enhanced, transforaminal lumbar epidural steroid injections (ESIs) and determine whether a “flash” (blood in the needle hub) or aspiration of blood can be used to predict a vascular injection. The incidence of flash or positive blood aspiration and the incidence of fluoroscopically confirmed vascular spread were observed in 670 patients treated with lumbosacral fluoroscopically guided transforaminal ESIs. Presence of a flash or positive aspiration was documented. Contrast was injected to determine whether the needle tip was intravascular. Seven hundred and sixty‐one transforaminal ESIs were included. The overall rate of intravascular injections was 11.2%. There was a statistically significant higher rate of intravascular injections (21.3%) noted with transforaminal ESIs performed at S1 (n = 178), compared with those at the lumbar levels (8.1%, n = 583). Using flash or positive blood aspirate to predict intravascular injections was 97.9% specific, but only 44.7% sensitive. Conclude there is a high incidence of intravascular injections in transforaminal ESIs that is significantly increased S1. Using a flash of blood aspiration to predict an intravascular injection is not sensitive, and therefore a negative flash or aspiration is not reliable. Fluoroscopically guided procedures without procedures without contrast confirmation are instilling medications intravascularly and therefore not into the desired epidural location. This finding confirms the need for not only fluoroscopic guidance but also contrast injection instillation in lumbosacral transforaminal ESIs.

Comment by Gabor B. Racz, M.D. This is a rather sobering prospective evaluation of needle placement while carrying out transforaminal lumbosacral epidural steroid injections. The authors have done 761 transforaminal epidural steroid injections with an intravascular injection rate of 11.2%. The S‐1 transforaminal injection had a 21.3% intravascular injection rate as evidenced by contrast injection. The aspiration was only 44.7% sensitive while using a 22‐gauge spinal needle. The intravascular injections in this study have not produced significant complications. The authors are looking for the illusive and imagined safe triangle while using a technique that clearly cannot achieve such a goal. In order to have a safe technique, it should work for all sites, and the incidence of intravenous injection in the sacral nerve root area is indicating less of an understanding as to the delivery of medication by the higher intravascular injection rate. Furthermore, the safe triangle of the L‐5 nerve root area can be dramatically altered by degenerative arthritis, bulging disc, rotational scoliosis, etc. Clearly, we have a serious technical problem with the way transforaminal injections are carried out as descried by the authors. The use of the 22‐guage spinal needle has not been designed for injections in hazardous areas such as transforaminal injection sites. Our approach, since the recognition of an even more serious problem, intrasegmental arterial injection followed by paraplegia, hemoplegia, Browns‐Sequard's Syndrome, and death has been to switch from sharp needle injections to the curved blunt needle that is very much less likely to penetrate the vessels around the nerve root or within the nerve root and reduce the damage to the nerve root as well as the vascular structures in this rather hazardous area. The number of injections carried out in this study clearly reflect one practice, and the paper does point out the hazard of the technique in terms of intravascular injections, but clearly, the numbers are not great enough to recognize a far greater hazard of segmental arterial intravascular injections where because of the small size of the artery, aspiration will be meaningless; injection of particulate, precipitated steroid in rare instances leads to infarction of the spinal cord where the blood supply to the conus medullaris area is via the L‐5 nerve root. I have seen three such cases where spinal cord injury is a consequence of segmental artery injection that is virtually impossible to recognize at the time of the injection. The authors need to be congratulated for bringing this topic to the forefront as clearly the technique needs to be significantly improved for all patients receiving transforaminal injections.