Needle Position Analysis in Cases of Paralysis From Transforaminal Epidurals: Consider Alternative Approaches to Traditional Technique

Abstract

Background: Transforaminal technique for epidural steroid injections, unlike other approaches, is uniquely associated with permanent, bilateral, lower extremity paralysis. Objective: To review the literature and analyze the reported cases of paralysis from lumbar transforaminal epidural steroid injections to possibly establish a cause and to prevent this complication. Study Design: Eighteen cases of paralysis from transforaminal epidural injection have been reported. We could analyze the position of the needle within the neural foramen based on the available images and/or description among 10 of these 18 cases. Five cases were performed with computed tomography guidance and 12 cases were performed with fluoroscopic guidance [unknown in one case]. Additionally, other variables associated with the procedure, including the technique, were also examined. Methods: Analysis of the needle position in the neural foramen in cases of paralysis from transforaminal epidural steroid injections. This analysis is based on images and/or description provided in published reports. Results: Paralysis in these cases seems to be associated with a well performed traditional safe triangle approach with good epidural contrast spreads. Analyzed data shows that 77.7% of the time, the needle was in the superior part of the foramen. In 71.4% of the cases, the needle was in the anterior part of the foramen. This coincides with the location of the radicular artery in the foramen. In 22.2%, the needle was in the midzone (neither in the superior nor inferior zone). No level was spared as this event occurred at every foramen from T12 to S1. Ten of these events happened during a left-sided procedure and 8 during a right-sided procedure. No relation to this complication was noted when other variables like type and size of the needles, side of the injection, local anesthetic, contrast, or volume of injectate were taken into consideration. Limitations: Only 18 cases of paralysis from transforaminal epidurals have been reported. Out of these, only 10 cases included images or descriptions which could be evaluated for our study. Conclusion: In light of the anatomical and radiological evidence in the literature that radicular arteries dwell in the superior part of the foramen and along with our needle position analysis, we suggest that the traditional technique of placing the needle in the superior and anterior part of the foramen must be reexamined. Alternative, safer techniques must be considered, one of which is described. Key words: Lumbar epidural injection, lumbar transforaminal, approach, selective nerve root block, paralysis, steroid, particulate, nonparticulate, safe triangle, radicular artery, artery of Adamkiewicz