OBJECTIVE: Reports of catastrophic neurologic injuries following lumbar transforaminal epidural steroid injections are rare but serious potential complications. The traditional method of performing lumbar transforaminal epidural steroid injections is in the "safe triangle" to avoid contact to the spinal nerve. Some authors advocate an alternative approach by placing the needle inferiorly in a region referred to as "Kambin's triangle" to avoid incurring arteries. This study aimed to determine the location of arteries within the L1-L4 intervertebral foramen in vivo, specifically if they lie within or in close proximity to the "safe triangle" or Kambin's triangle using CT angiograms of the abdomen and pelvis. STUDY DESIGN: The authors retrospectively evaluated the location in vivo of arterial vessels in the intervertebral foramen from L1 to L4 in patients who underwent abdominopelvic CT angiograms for aortic vascular disease. The data were reanalyzed to confirm inter-rater reliability. RESULTS: Arteries were found in both the safe triangle and Kambin's triangle at a statistically significant rate (P < 0.05). CONCLUSIONS: In this group of patients, an artery was found in either the safe triangle or in Kambin's triangle frequently, suggesting the location of these arteries can be quite variable. Physicians performing these procedures should use universal precautions to avoid inadvertent injection into the lumbar spinal arteries and minimize potential complications regardless of the approach. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. 2016. This work is written by US Government employees and is in the public domain in the US.
OBJECTIVE: Reports of catastrophic neurologic injuries following lumbar transforaminal epidural steroid injections are rare but serious potential complications. The traditional method of performing lumbar transforaminal epidural steroid injections is in the "safe triangle" to avoid contact to the spinal nerve. Some authors advocate an alternative approach by placing the needle inferiorly in a region referred to as "Kambin's triangle" to avoid incurring arteries. This study aimed to determine the location of arteries within the L1-L4 intervertebral foramen in vivo, specifically if they lie within or in close proximity to the "safe triangle" or Kambin's triangle using CT angiograms of the abdomen and pelvis. STUDY DESIGN: The authors retrospectively evaluated the location in vivo of arterial vessels in the intervertebral foramen from L1 to L4 in patients who underwent abdominopelvic CT angiograms for aortic vascular disease. The data were reanalyzed to confirm inter-rater reliability. RESULTS: Arteries were found in both the safe triangle and Kambin's triangle at a statistically significant rate (P < 0.05). CONCLUSIONS: In this group of patients, an artery was found in either the safe triangle or in Kambin's triangle frequently, suggesting the location of these arteries can be quite variable. Physicians performing these procedures should use universal precautions to avoid inadvertent injection into the lumbar spinal arteries and minimize potential complications regardless of the approach. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. 2016. This work is written by US Government employees and is in the public domain in the US.