Digital subtraction angiography vs. real-time fluoroscopy for detection of intravascular injection during transforaminal epidural block

Background: Transforaminal epidural block (TFEB) is an effective treatment option for radicular pain. To reduce complications from intravascular injection during TFEB, use of imaging modalities such as real-time fluoroscopy (RTF) or digital subtraction angiography (DSA) has been recom mended. In this study, we investigated whether DSA improved the detection of intravascular in jection during TFEB at the whole spine level compared to RTF. Methods: We prospectively examined 316 patients who underwent TFEB. After confirmation of final needle position using biplanar fluoroscopy, 2 mL of nonionic contrast medium was injected at a rate of 0.5 mL/s under RTF; 30 s later, 2 mL of nonionic contrast medium was injected at a rate of 0.5 mL/s under DSA. Results: Thirty-six intravascular injections were detected for an overall rate of 11.4% using RTF, with 45 detected for a rate of 14.2% using DSA. The detection rate using DSA was statistically dif ferent from that using RTF (p=0.004). DSA detected a significantly higher proportion of intravas cular injections at the cervical level than at the thoracic (p=0.009) and lumbar (p=0.011) levels. Conclusion: During TFEB at the whole spine level, DSA was better than RTF for the detection of intravascular injection. Special attention is advised for cervical TFEB, because of a significantly higher intravascular injection rate at this level than at other levels.