Accuracy of live fluoroscopy to detect intravascular injection during lumbar transforaminal epidural injections

Abstract

Background: Complications following lumbar transforaminal epidural injection are frequently related to inadvertent vascular injection of corticosteroids. Several methods have been proposed to reduce the risk of vascular injection. The generally accepted technique during epidural steroid injection is intermittent fluoroscopy. In fact, this technique may miss vascular uptake due to rapid washout. Because of the fleeting appearance of vascular contrast patterns, live fluoroscopy is recommended during contrast injection. However, when vascular contrast patterns are overlapped by expected epidural patterns, it is hard to distinguish them even on live fluoroscopy.

Methods: During 87 lumbar transforaminal epidural injections, dynamic contrast flows were observed under live fluoroscopy with using digital subtraction enhancement. Two dynamic fluoroscopy fluoroscopic images were saved from each injection. These injections were performed by five physicians with experience independently. Accuracy of live fluoroscopy was determined by comparing the interpretation of the digital subtraction fluoroscopic images.

Results: Using digital subtraction guidance with contrast confirmation, the twenty cases of intravascular injection were found (the rate of incidence was 23%). There was no significant difference in incidence of intravascular injections based either on gender or diagnosis. Only five cases of intravascular injections were predicted with either flash or aspiration of blood (sensitivity = 25%). Under live fluoroscopic guidance with contrast confirmation to predict intravascular injection, twelve cases were predicted (sensitivity = 60%).

Conclusions: This finding demonstrate that digital subtraction fluoroscopic imaging is superior to blood aspiration or live fluoroscopy in detecting intravascular injections with lumbar transforaminal epidural injection.

Keywords: digital subtraction image; epidural injection; fluoroscopy; intravascular injection.

Fig. 1

(A) An anteroposterior live fluoroscopic image taken during contrast injection for right L5-S1 transforaminal steroid injection. It shows the epidural contrast pattern without vascular injection. (B) An anteroposterior digital subtraction image taken during same injection. It shows a simultaneous epidural and vascular contrast pattern.