Case Report

Stroke following Epidural Injections—Case Reportand Review of Literature

Alexandra Popescu, MD, Daniel Lai, MD, Angela Lu, MD, Kathy Gardner, MDFrom the Department of Neurology, Epilepsy Division, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (AP); Department of Neurology, University ofPittsburgh School of Medicine, Pittsburgh, Pennsylvania (DL); and Division of General Neurology, Department of Neurology, University of Pittsburgh School of Medicine,Pittsburgh, Pennsylvania (AL, KG).

Keywords: Infarction, spinal cord,steroids.

Acceptance: Received October 3, 2010,and in revised form February 13, 2011.Accepted for publication March 15, 2011.

Correspondence: Address correspon-dence to Daniel Lai, MD, Suite 811,Kaufmann Medical Building, 3471 FifthAvenue, Pittsburgh, PA 15213. E-mail:laidk@upmc.edu.

Conflict of Interest: None.

J Neuroimaging 2011;XX:1-4.DOI: 10.1111/j.1552-6569.2011.00615.x

A B S T R A C T

BACKGROUND AND PURPOSETo describe a growing number of cases associated with spinal cord and posterior circulationischemia as a complication of cervical epidural steroid injection (CESI).METHODSCase report and review of literature.RESULTSSixteen cases of spinal cord and posterior circulation ischemia were analyzed. Two caseshad transient symptoms and 10 had long-term sequelae. Four resulted in death.CONCLUSIONInfarction is a rare but potentially devastating complication of CESI. It may occur despitethe use of fluoroscopic guidance.

IntroductionCervical epidural steroid injection (CESI) is used to conserva-tively manage intractable radicular pain. Despite the lack ofprospective trials, steroid injection is considered safe and effi-cacious. The two approaches for cervical injection are trans-foraminal and interlaminar. The transforaminal injection hasthe advantage of directly delivering the injectate onto the targetnerve by entering through the foramen tangential to its poste-rior wall. The procedure requires fluoroscopic guidance to allowdirect visualization of the epidural space and vertebral artery.The vertebral artery rises closely in front of the zygapophysialjoint.1 Following needle drawback negative for cerebrospinalfluid (CSF) or blood, contrast is injected and spreads first withinthe intervertebral foramen then into the epidural space untilthe dural sleeve is outlined. Next, a small volume of local anes-thetic is injected, followed by corticosteroid. The procedure isperformed on an outpatient basis and is thought to have a lowcomplication rate. Neurologic sequelae following CESI havebeen reported as increased pain (7%), transient nonpositionalheadache (5%), vasovagal reaction (2%), facial flushing (1.5%),and dural puncture (.3%).1

Case ReportA 66-year-old woman underwent transforaminal CESI for reliefof intractable neck and shoulder pain. Under fluoroscopic guid-ance using Isovue dye, a 22-guage Quicke needle was placed

and its position confirmed. Forty milligrams of methylpred-nisolone acetate was injected at the C5-C6 level. The patientdeveloped flaccid quadriplegia within 45 minutes. Magnetic res-onance imaging (MRI) obtained 2 hours postprocedure showedno signs of hemorrhage. The patient was administered methyl-prednisolone 125 mg intravenously and transferred to our fa-cility. Neurological examination revealed intact mental statusand cranial nerves. There was flaccid quadriplegia with a C5dissociated sensory level. Vibratory sensation and propriocep-tion were preserved but there was loss of sensation to pinprickand temperature below C5. Reflexes were absent, rectal tonewas decreased, and Babinski reflex was present bilaterally. TheMRI showed a longitudinal gadolinium-enhancing lesion fromC3 to T2 with an “owl’s eyes” pattern present at C5 (Fig 1A, B)16 hours postprocedure. On postprocedure day 2, a repeat MRIshowed edema of the entire cervical spinal cord and restricteddiffusion at C4-C6, confirming our clinical suspicion of a cordinfarction (Fig 1C, D). MRI of the brain with axial T1-weightedfat-suppression images and MRA of intracranial and extracra-nial vessels were negative for vertebral artery dissection. By thethird week, the patient remained quadriplegic and repeat MRIshowed resolving spinal cord edema.

We conducted a literature search for cases of neurologiccomplications related to CESI on PubMed using MeSH resultswith the following search terms: spinal cord, infarction, cervi-cal, steroid, transforaminal, injection. We present 16 cases, 15

Copyright ◦C 2011 by the American Society of Neuroimaging 1

Fig 1. Gadolinium-enhanced T1-weighted images revealed en-hancement at C3-T2 levels (A) predominantly in the anterior graymatter with an “owl’s eyes” pattern the level of C5 (B). MRI postpro-cedure day 2 showed edema of the entire cervical spinal cord (C)and restricted diffusion at C4-C6 levels (D).

of which were found on review of the literature. Methods werecharacterized according to whether the procedure was typical,that is, fluoroscopy confirmed needle placement with negativeaspiration of both blood and CSF, or atypical where fluoroscopywas unused, aspiration was positive or the procedure was oth-erwise unspecified.

DiscussionA survey of 1,340 pain specialists (287 responders)2 re-ported 78 complications following transforaminal CESI in theircumulative experience. These included 30 infarction cases(brain and/or spinal cord) with 13 cases resulting in fatality.Our literature review found six cases of posterior circulation in-farction (three typical, three atypical procedures) and 10 casesof spinal cord ischemia (three typical, seven atypical proce-dures) following CESI (one case with both cord and cerebellarinfarction).

Our case demonstrated that with fluoroscopic guidance andnegative needle aspiration an extensive anterior spinal arterycord infarct can occur in the absence of vertebral artery dissec-tion. The injury was likely due to ischemia in the distributionof a radicular artery that feeds the anterior spinal artery. Fur-man et al3 reported a study with 504 transforaminal cervicalinjections and found a 19.4% rate of fluoroscopy-confirmed in-travascular injections despite no blood on needle drawback.Needle flashback for blood was estimated to be 97% specific,but only 45.9% sensitive for identifying intravascular injection.3

An anatomic dissection of 95 cervical intervertebral foraminashowed an arterial vessel proximal to the posterior aspect ofthe foraminal opening in 21 cases. Seven of eight spinal arterialbranches from the ascending or deep cervical artery enteredposteriorly.4 Thus, the posterior placement of the needle doesnot exclude the possibility of vascular injury despite avoidingthe vertebral artery. It is possible to inject an artery even if noblood is seen on needle drawback due to the low sensitivity ofthis method, and possibly even if position is verified using fluo-roscopy according to the result of our case and those reportedin Table 1.

Periprocedure infarctions due to either vasospasm or an em-bolus from particulate matter associated with the steroid injec-tion have been postulated as mechanisms for causing neuro-logic symptoms. A review of this case series shows that of the16 cases, 12 (75%) involved injection of steroids. Scalon et alfound a rate of 90% of cases involved in neurologic compli-cations were associated with steroid injection, 79% of whichinvolved methylprednisolone use.2 Tiso et al suggest that cor-ticosteriod suspensions contain particles which may occludearterioles.5

Steriods were used in 12 of the reported cases in this se-ries. Of the 12 cases, at least 10 reported long-term neurologicconsequences ranging from severe paresis to death (two caseoutcomes are unknown). The four cases without known sterioduse seem to exhibit a more benign case with outcomes rangingfrom a single fixed deficit to complete resolution.6-9 More dataare needed to determine the efficacy of transforaminal injec-tions. Anderberg et al reported a study of 40 patients showedthat injection of a combination of steroid with local anestheticlacked superiority in symptom relief when compared with in-jection of local anesthetic combined with saline.10

Infarction is a rare but potentially devastating complicationof CESI. It may occur despite the use of fluoroscopic guidance.Patients and practitioners need to be aware that there is a riskof spinal cord and brain infarction related to the transforaminalCESI and that both safety and efficacy for the procedure are inquestion.

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Table 1. Anaylsis of Cases of Spinal Cord and Posterior Circulation Ischemia

Case/ Injection Presentation/ClinicalReference Site Medications Method Course Investigations Outcome

1 C5-C6 Methylprednisolone Typical Flaccid quadriplegia,dissociative sensoryloss with C5 level

MRI: cord infarct atC4-C6

3 weeks: quadriplegic

212 (R)C5-C6 TriamcinoloneBupivacaine

Typical Flaccid paralysis,transient coma thenquadriplegic

MRI: extensive cordinfarction

Death

313 (L)C5-C6 TriamcinoloneBupivacaine

Typical Quadriplegia,dissociative sensoryloss

MRI: extensive cordinfarction C2-T1

Unknown

46 C6-C7 Methylprednisolone Atypical Quadriplegic,respiratory arrest

MRI: no infarction 6 months: regained somestrength requiring dailyassistance

515 (L)C5-6(L)C6-7

MethylprednisoloneBupivacaine

Atypical Arms paretic withparaplegia, T4sensory level

MRI: cervical cordedema and medullaryinfarction

8 weeks: ambulating withwalker

614 (R)C6-C7 Lidocaine Atypical Transient quadriparesis,dissociative sensoryloss

None 20 minutes: resolution

718 (L)C6-C7(L)C7-C8

Steriod not named Atypical Numbness andweakness of (L) arm

MRI: petechialhemorrhages inlateral cord

(L) C7 radiculopathy withweakness and numbness

87 (L)C5-C6 Unknown Atypical Confusion, (L) armweakness

CT: dissection of leftvertebral artery at (L)C3-C6

24 hours: resolution

919 (L)C6-C7 TriamcinoloneMepivacaine

Atypical Flaccid quadriplegia,respiratory arrest, C4sensory level

MRI: high cervical toupper thoracic cordedema

3 months: breathingunassisted

108 (L)C6-C7 None (contrast only) Atypical Quadriparesis, (L)C6sensory level

CT: intracord air bubbleMRI: cervical cord

edema

(L) arm paresis otherwiserestored strength

115 (R)C5-C6 TriamcinoloneBupivacaine

Typical Transientunresponsiveness,quadriplegia

MRI: cerebellar infarct. Death

1216 (R)C7-T1 MethylprednisoloneLidocaine

Typical Neck pain, headache,nausea thenintermittent apnea,posturing

MRI: cerebellar infarctwith edema andsubsequent herniation

Posterior fossa craniectomyand meningitis.Recovered with diplopiaand memory deficits

1317 (L)C5-C6 Methylprednisolone Typical Nausea, vomiting andheadache followed bydecreasedconsciousness anddysarthria

MRI: midbrain, pons, Lthalamic infarction.

Death

1418 (L)C5-C6 BetamethasoneLidocaine

Atypical Transientunresponsiveness.Dysarthria, ataxia,numb arms, (L) armplegic, (R) arm paretic

MRI: cerebellar infarctand C1-C4 cordinfarct

Unknown

159 (L)C5-C6 Anesthetics,unspecificed

Atypical Nystagmus. Subsequentblindness, seizures,obtundation, aphasia,dysphagia

MRI: L occipital cortexcerebral edema

Day 30: memory deficitsand (R) homonymoushemianopia

1611 (L)C6-C7 MethylprednisoloneBupivacaine

Atypical Immediatelynoncommunicative

CT: brainstemhemorrhage,intraventricularhemorrhage

Death

(L) =left; (R) = right; (C) = cervical.

Popescu et al: Stroke following Epidural Injections 3

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