Background: For decades, epidural steroid injections have been an effective tool in the
management of many pain related conditions, including lumbar radiculopathy. Transforaminal
epidural steroid injections in particular have been reported to potentially result in central nervous
system infarctions which have not been reported with interlaminar epidural steroid injections, while
providing comparable efficacy. This rare, catastrophic complication has been attributed by some
authors to be due to vascular injury secondary to vasospasm, thrombus formation, dissection, as
well as concerns with placing the needle at the so-called “safe triangle.” Others, however, have
proposed it to be secondary to embolization of the vessel by particulate steroids. This has led to the
recommendation of the use of soluble steroids such as dexamethasone when performing TFESI’s,
despite concerns over its efficacy and potential for neurotoxicity in the literature. Furthermore,
there have also been multiple studies which have revealed that IV dexamethasone is analgesic and
that peri-neural dexamethasone is no more effective than IV dexamethasone.
Case History: The present case involves a 60-year-old patient with right back and radicular
leg pain for 3 years. Two right L4 TFESI’s had been performed with betamethasone several years
prior with satisfactory results, until the patient presented to the physician with a pain recurrence
of 6 weeks of duration. The patient again underwent a right L4 TFESI with dexamethasone,
which provided good relief after 2 weeks. The patient underwent a repeat right L4 TFESI with
dexamethasone which was followed by a prompt onset of lower extremity numbness, weakness,
and incontinence that was discovered to be related to a conus infarction. While this is the
first publicly reported case of a conus medullaris infarction following a lumbar transforaminal
injection utilizing dexamethasone, the incidence of these reports may rise as the prevalence of
dexamethasone use increases in clinical practice.
Conclusion: The spinal cord infarction with TFESI’s may occur related to various mechanisms,
regardless of the type of particulate or non-particulate steroid used during these procedures.
Key words: Dexamethasone, particulate steroids, non-particulate steroids, conus medullaris
infarction, cauda equina syndrome, transforaminal epidural steroid injection, epidural steroid
injection, safe triangle, methylprednisolone, paralysis