Intravascular flow patterns in transforaminal epidural injections: a comparative study of the cervical and lumbar vertebral segments.

Background: Transforaminal epidural injection (TEI) is commonly used in the treatment of radicular pain. However, there have been many published cases of serious complications after a TEI, occurring most often in cervical levels. One of the presumptive reasons for this complication is inadvertent intravascular injection. We sought to identify the incidence of intravascular injections in cervical and lumbar spinal segments during TEI.

Methods: All patients with radicular symptoms or herpes zoster-associated pain underwent cervical and lumbar TEIs (LTEIs) prospectively by one of the authors. After an ideal needle position was confirmed by biplanar fluoroscopy, 3 mL of a mixture containing nonionic contrast and normal saline was continuously injected at the rate of 0.3-0.5 mL/s with real-time fluoroscopic visualization.

Results: One hundred eighty-two TEIs were performed. Fifty-six cases (30.8%) showed intravascular spreading patterns, 45 cases occurring during a cervical TEI (CTEI) and 11 during a LTEI. The incidences of simultaneous perineural and vascular injection in cervical and LTEIs were 52.1% and 9%, respectively, and pure vascular flow pattern rates in cervical and LTEIs were 11.3% and 0.9%, respectively.

Conclusion: The incidence of vascular injection in CTEIs is significantly higher than in LTEIs, suggesting that CTEIs should be performed more cautiously. Furthermore, the vascular injection rate of CTEIs is much higher than that previously reported. This finding suggests the need for a proper volume of contrast injection (3 mL) to detect vascular flow, especially in simultaneous perineural and vascular injections.