Transforaminal Injection of Steroids
Transforaminal injection of steroids, often used in the treatment of acute radicular pain, has been linked to cases of spinal cord infarction, cortical blindness, paralysis, and death.
24,
50,
61 The presumed mechanism of these complications involves unintentional needle entry into a small artery that traverses the intervertebral foramen to join the arterial supply to the spinal cord or posterior circulation of the brain. This can occur at various levels, including the vertebral artery anterior to the cervical intervertebral foramina, or the spinal medullary or radicular arteries within the foramina at variable levels within the cervical,
62,
63 thoracic, lumbar, and sacral portions of the spine. Subsequent injection of particulate steroid preparations can result in occlusion of the distal arterioles within the spinal cord or brain and lead to infarction.
61 In vitro studies note that methylprednisolone has the largest particles, betamethasone the smallest, and dexamethasone has no particulate matter.
64 While evidence of unintended injection into perispinal vessels during transforaminal injection has been reported, direct evidence to confirm or refute the role of particulate steroids in causing subsequent neuronal injury is lacking (
Table 6).