Medial branch blockade of the lumbar facet joints is widely performed and generally accepted as a safe intervention. We present a case of neurological damage following a medial branch blockade with
local anesthetic and
steroid. A patient suffering from chronic
low back pain radiating to the buttocks and thighs underwent nine medial branch blockades over a few years. Three months after successful back surgery to remove a herniated L2-3 disk, the
pain recurred, and left L3-4 , L4-5, and L5 -S1 medial branch blocks were performed under fluoroscopy. Immediately following the procedure, the patient developed
paraparesis in both legs, loss of pinprick but preserved fine touch sensation, proprioception, and sphincter sensory and motor function. MRI showed ischemic lesions of the cauda equina. Direct needle
trauma was discounted as a cause, due to the bilateral neurological deficit, plus the lack of
pain during the procedure. Particulate
steroid preparations can form aggregates, which may embolize and block small terminal arteries, causing neurological damage. Although the patient received nine sets of
injections uneventfully during the previous 36 months, this procedure took place 3 months following spinal surgery. This rare, but catastrophic case of
cauda equina syndrome occurred following L3-4 , L4-5 , and L5 -S1 medial branch blockades 3 months after spinal surgery, which is believed to be caused by accidental
intra-arterial injection of particulate
methylprednisolone, with consequent aggregates causing blockage and ensuing
ischemia. Therefore we suggest particulate
steroid preparations should not be used in axial
spinal injection.