Incidence of intravascular uptake in lumbar spinal injection procedures

Study Design. Multicenter, prospective, observational study. Objectives. To document the incidence of and factors associated with intravascular uptake during lumbar spinal injection procedures. Summary of Background Data. In prior reports, the incidence of inadvertent intravascular needle placement during contrast-enhanced, fluoroscopically guided lumbar spinal injection procedures has been incidentally noted to range from 6.4% to 9.2%. We present the first systematic prospective documentation of intravascular uptake of contrast dye during different types of lumbar injection procedures. Methods. Fifteen interventional spine physicians in seven centers recorded data regarding intravascular uptake during 1219 contrast-enhanced, fluoroscopically guided lumbar spinal injection procedures. Results. The overall incidence of intravascular uptake during lumbar spinal injection procedures as determined by contrast enhanced fluoroscopic observation is 8.5%. Caudal and transforaminal routes have the highest rates at 10.9% and 10.8%, respectively, followed by zygapophyseal joint (6.1%), sacroiliac joint (5.3%), and translaminar (1.9%) injections. Intravascular uptake is twice as likely to occur in those patients over rather than under 50 years of age. Preinjection aspiration failed to produce a flashback of blood in 74% of cases that proved to be intravascular upon injection of contrast dye. Conclusion. The incidence of intravascular uptake during lumbar spinal injection procedures is approximately 8.5%. The route of injection and the age of the patient greatly affect this rate. Absence of flashback of blood upon preinjection aspiration does not predict extravascular needle placement. Contrast-enhanced, fluoroscopic guidance is recommended when doing lumbar spinal injection procedures to prevent inadvertent intravascular uptake of injectate.