Root Cause Analysis of Paraplegia Following Transforaminal Epidural Steroid Injections: The ‘Unsafe’ Triangle

The utilization rate of transforaminal epidural steroid injections (TFESIs), an electivediagnostic and therapeutic spinal procedure, has risen dramatically over the pastdecade. In 2006 alone, greater than 300,000 thoracolumbar TFESIs were performedon Medicare beneficiaries. Despite the purported superiority of the transforaminalroute, compared to other modes of epidural injection, TFESIs are associated withpotential hazards.The artery of Adamkiewicz (ARM) might enter any mid thoracic, lower thoracic,or lumbar foramen; the exact level, in a specific patient, will be unknown to theproceduralist· The authors propose that the “safe triangle” approach to transforaminalepidural injections is not safe (TFESIs).Injury to the ARM can lead to paraplegia, independent of operator skill or adjuvantsafety initiatives (digital subtraction angiography, local anesthetic test dose). Injury tothe ARM is a “black swan” event. The authors believe that catastrophic injury may beaverted when performing TFESIs by avoiding the “un-safe,” superoanterior trianglein the foramen and that transforaminal injections should be performed at the inferioraspect of the foramen, known as Kambin’s triangle.Key words: transforaminal, spinal cord, artery of Adamkiewicz, paraplegia, foramen,radiculomedullary, root cause analysis, patient safety, medico-legal, black swan