Intravascular injection of contrast during lumbar discography: a previously unreported complication.

OBJECTIVE Report a case of intravascular contrast injection during lumbar discography. SETTING An academic University spine center. PATIENT Forty-year-old woman with L5-S1 degenerative disk disease and persistent low back pain. INTERVENTION The patient failed to respond to multiple conservative treatments. In consideration of surgical treatment, discography was requested. RESULTS A 22G needle was inserted to the central nucleus by a left posterolateral approach. Discography was performed at L4-5 and L5-S1. Testing was performed with pressure manometry, beginning with the L4-5 disk. The pressure increased with contrast injection in the manner of a normal disk. At 45 psi there was a sudden drop to 20 psi. Lateral views obtained during contrast injection demonstrated flow from a central nucleogram cephalad into the anterior epidural space. Images obtained with live fluoroscopy demonstrated a vascular flow pattern, confirmed with lateral and anterior-posterior views. The needle tip was repositioned anterior and superior. Repeat injection resulted in an identical vascular pattern. From the time the pressure dropped, contrast flowed in the vascular pattern without propagation of the nucleogram or increase in intradiscal pressure. The patient was asymptomatic throughout the injection at L4-5. Injection at L5-S1 demonstrated a severely degenerative nucleogram and reproduced the patient's usual low back pain. CONCLUSIONS Vascular uptake of contrast can occur during lumbar discography, even when the needle tip is ideally located.