Background: Transforaminal epidural block (TFEB) with local anesthetics and steroid is effective to treat spinal radicular pain. However, inadvertent intravascular injection can lead to severe neurologic complications. Digital subtraction angiography (DSA) is an imaging technique that can clearly visualize the blood vessels from surrounding bones or dense soft tissues by subtracting the pre-contrast image from the image after injecting contrast. In this study, we investigated whether DSA can increase the detection of intravascular injection during cervical TFEB, compared to real time fluoroscopy (RTF).
Methods: We prospectively examined 137 cervical TFEBs. The needle position was confirmed using biplanar fluoroscopy and 2 ml of nonionic contrast media was injected at the rate of 0.5 ml/sec under RTF. Thirty seconds later, 2 ml of nonionic contrast media was injected at the rate of 0.5 ml/sec under DSA. 
Results: There is no significant difference in detection rate of intravascular penetration was between RTF and DSA (30.7 % vs 34.3%, p>0.05).
Conclusions: In this study, DSA did not improve the detection rate of intravascular injection during cervical TEB, compared to RTF.

The detection rate of intravascular penetration during cervical transforaminal epidural block using digital subtraction angiography, compared to real-time fluoroscopy