Case Report Stroke following Epidural Injections—Case Report and Review of Literature Alexandra Popescu, MD, Daniel Lai, MD, Angela Lu, MD, Kathy Gardner, MD From the Department of Neurology, Epilepsy Division, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (AP); Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (DL); and Division of General Neurology, Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (AL, KG). ABSTRACT BACKGROUND AND PURPOSE To describe a growing number of cases associated with spinal cord and posterior circulation ischemia as a complication of cervical epidural steroid injection (CESI). METHODS Case report and review of literature. RESULTS Keywords: Infarction, steroids. spinal cord, Acceptance: Received October 3, 2010, and in revised form February 13, 2011. Accepted for publication March 15, 2011. CONCLUSION Correspondence: Address correspondence to Daniel Lai, MD, Suite 811, Kaufmann Medical Building, 3471 Fifth Avenue, Pittsburgh, PA 15213. E-mail: laidk@upmc.edu. Infarction is a rare but potentially devastating complication of CESI. It may occur despite the use of fluoroscopic guidance. Conflict of Interest: None. Sixteen cases of spinal cord and posterior circulation ischemia were analyzed. Two cases had transient symptoms and 10 had long-term sequelae. Four resulted in death. J Neuroimaging 2011;XX:1-4. DOI: 10.1111/j.1552-6569.2011.00615.x Introduction Cervical epidural steroid injection (CESI) is used to conservatively manage intractable radicular pain. Despite the lack of prospective trials, steroid injection is considered safe and efficacious. The two approaches for cervical injection are transforaminal and interlaminar. The transforaminal injection has the advantage of directly delivering the injectate onto the target nerve by entering through the foramen tangential to its posterior wall. The procedure requires fluoroscopic guidance to allow direct visualization of the epidural space and vertebral artery. The vertebral artery rises closely in front of the zygapophysial joint.1 Following needle drawback negative for cerebrospinal fluid (CSF) or blood, contrast is injected and spreads first within the intervertebral foramen then into the epidural space until the dural sleeve is outlined. Next, a small volume of local anesthetic is injected, followed by corticosteroid. The procedure is performed on an outpatient basis and is thought to have a low complication rate. Neurologic sequelae following CESI have been reported as increased pain (7%), transient nonpositional headache (5%), vasovagal reaction (2%), facial flushing (1.5%), and dural puncture (.3%).1 Case Report A 66-year-old woman underwent transforaminal CESI for relief of intractable neck and shoulder pain. Under fluoroscopic guidance using Isovue dye, a 22-guage Quicke needle was placed and its position confirmed. Forty milligrams of methylprednisolone acetate was injected at the C5-C6 level. The patient developed flaccid quadriplegia within 45 minutes. Magnetic resonance imaging (MRI) obtained 2 hours postprocedure showed no signs of hemorrhage. The patient was administered methylprednisolone 125 mg intravenously and transferred to our facility. Neurological examination revealed intact mental status and cranial nerves. There was flaccid quadriplegia with a C5 dissociated sensory level. Vibratory sensation and proprioception were preserved but there was loss of sensation to pinprick and temperature below C5. Reflexes were absent, rectal tone was decreased, and Babinski reflex was present bilaterally. The MRI showed a longitudinal gadolinium-enhancing lesion from C3 to T2 with an “owl’s eyes” pattern present at C5 (Fig 1A, B) 16 hours postprocedure. On postprocedure day 2, a repeat MRI showed edema of the entire cervical spinal cord and restricted diffusion at C4-C6, confirming our clinical suspicion of a cord infarction (Fig 1C, D). MRI of the brain with axial T1-weighted fat-suppression images and MRA of intracranial and extracranial vessels were negative for vertebral artery dissection. By the third week, the patient remained quadriplegic and repeat MRI showed resolving spinal cord edema. We conducted a literature search for cases of neurologic complications related to CESI on PubMed using MeSH results with the following search terms: spinal cord, infarction, cervical, steroid, transforaminal, injection. We present 16 cases, 15 ◦ Copyright C 2011 by the American Society of Neuroimaging 1 Discussion Fig 1. Gadolinium-enhanced T1-weighted images revealed enhancement at C3-T2 levels (A) predominantly in the anterior gray matter with an “owl’s eyes” pattern the level of C5 (B). MRI postprocedure 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 were characterized according to whether the procedure was typical, that is, fluoroscopy confirmed needle placement with negative aspiration of both blood and CSF, or atypical where fluoroscopy was unused, aspiration was positive or the procedure was otherwise unspecified. 2 Journal of Neuroimaging Vol xx No x 2011 A survey of 1,340 pain specialists (287 responders)2 reported 78 complications following transforaminal CESI in their cumulative 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 infarction (three typical, three atypical procedures) and 10 cases of spinal cord ischemia (three typical, seven atypical procedures) following CESI (one case with both cord and cerebellar infarction). Our case demonstrated that with fluoroscopic guidance and negative needle aspiration an extensive anterior spinal artery cord infarct can occur in the absence of vertebral artery dissection. The injury was likely due to ischemia in the distribution of a radicular artery that feeds the anterior spinal artery. Furman et al3 reported a study with 504 transforaminal cervical injections and found a 19.4% rate of fluoroscopy-confirmed intravascular 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 foramina showed an arterial vessel proximal to the posterior aspect of the foraminal opening in 21 cases. Seven of eight spinal arterial branches from the ascending or deep cervical artery entered posteriorly.4 Thus, the posterior placement of the needle does not exclude the possibility of vascular injury despite avoiding the vertebral artery. It is possible to inject an artery even if no blood is seen on needle drawback due to the low sensitivity of this method, and possibly even if position is verified using fluoroscopy according to the result of our case and those reported in Table 1. Periprocedure infarctions due to either vasospasm or an embolus from particulate matter associated with the steroid injection have been postulated as mechanisms for causing neurologic symptoms. A review of this case series shows that of the 16 cases, 12 (75%) involved injection of steroids. Scalon et al found a rate of 90% of cases involved in neurologic complications were associated with steroid injection, 79% of which involved methylprednisolone use.2 Tiso et al suggest that corticosteriod suspensions contain particles which may occlude arterioles.5 Steriods were used in 12 of the reported cases in this series. Of the 12 cases, at least 10 reported long-term neurologic consequences ranging from severe paresis to death (two case outcomes are unknown). The four cases without known steriod use seem to exhibit a more benign case with outcomes ranging from a single fixed deficit to complete resolution.6-9 More data are needed to determine the efficacy of transforaminal injections. Anderberg et al reported a study of 40 patients showed that injection of a combination of steroid with local anesthetic lacked superiority in symptom relief when compared with injection of local anesthetic combined with saline.10 Infarction is a rare but potentially devastating complication of CESI. It may occur despite the use of fluoroscopic guidance. Patients and practitioners need to be aware that there is a risk of spinal cord and brain infarction related to the transforaminal CESI and that both safety and efficacy for the procedure are in question. Table 1. Anaylsis of Cases of Spinal Cord and Posterior Circulation Ischemia Case/ Reference Injection Site 1 Presentation/Clinical Course Medications Method C5-C6 Methylprednisolone Typical 212 (R)C5-C6 Triamcinolone Bupivacaine Typical 313 (L)C5-C6 Triamcinolone Bupivacaine Typical 46 C6-C7 Methylprednisolone Atypical 515 (L)C5-6 (L)C6-7 Methylprednisolone Bupivacaine Atypical 614 (R)C6-C7 Lidocaine Atypical 718 (L)C6-C7 (L)C7-C8 Steriod not named Atypical 87 (L)C5-C6 Unknown Atypical Confusion, (L) arm weakness 919 (L)C6-C7 Triamcinolone Mepivacaine Atypical 108 (L)C6-C7 None (contrast only) Atypical Flaccid quadriplegia, respiratory arrest, C4 sensory level Quadriparesis, (L)C6 sensory level 115 (R)C5-C6 Triamcinolone Bupivacaine Typical 1216 (R)C7-T1 Methylprednisolone Lidocaine Typical 1317 (L)C5-C6 Methylprednisolone Typical 1418 (L)C5-C6 Betamethasone Lidocaine Atypical 159 (L)C5-C6 Anesthetics, unspecificed Atypical 1611 (L)C6-C7 Methylprednisolone Bupivacaine Atypical Flaccid quadriplegia, dissociative sensory loss with C5 level Flaccid paralysis, transient coma then quadriplegic Quadriplegia, dissociative sensory loss Quadriplegic, respiratory arrest Arms paretic with paraplegia, T4 sensory level Transient quadriparesis, dissociative sensory loss Numbness and weakness of (L) arm Transient unresponsiveness, quadriplegia Neck pain, headache, nausea then intermittent apnea, posturing Nausea, vomiting and headache followed by decreased consciousness and dysarthria Transient unresponsiveness. Dysarthria, ataxia, numb arms, (L) arm plegic, (R) arm paretic Nystagmus. Subsequent blindness, seizures, obtundation, aphasia, dysphagia Immediately noncommunicative Investigations Outcome MRI: cord infarct at C4-C6 3 weeks: quadriplegic MRI: extensive cord infarction Death MRI: extensive cord infarction C2-T1 Unknown MRI: no infarction 6 months: regained some strength requiring daily assistance 8 weeks: ambulating with walker MRI: cervical cord edema and medullary infarction None MRI: petechial hemorrhages in lateral cord CT: dissection of left vertebral artery at (L) C3-C6 MRI: high cervical to upper thoracic cord edema CT: intracord air bubble MRI: cervical cord edema MRI: cerebellar infarct. MRI: cerebellar infarct with edema and subsequent herniation MRI: midbrain, pons, L thalamic infarction. 20 minutes: resolution (L) C7 radiculopathy with weakness and numbness 24 hours: resolution 3 months: breathing unassisted (L) arm paresis otherwise restored strength Death Posterior fossa craniectomy and meningitis. Recovered with diplopia and memory deficits Death MRI: cerebellar infarct and C1-C4 cord infarct Unknown MRI: L occipital cortex cerebral edema Day 30: memory deficits and (R) homonymous hemianopia CT: brainstem hemorrhage, intraventricular hemorrhage Death (L) =left; (R) = right; (C) = cervical. Popescu et al: Stroke following Epidural Injections 3 References 1. Rathmell J, Aprill C, Bogduk N. Cervical transforaminal injection of steroids. Anesthesiology 2004;100:1595-1600. 2. Scalon GC, Moeller-Bertram T, Romanowsky SM, et al. Cervical transforaminal epidural steroid injections: more dangerous than we think? Spine 2007;32:1249-1256. 3. 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