Elsevier

The Spine Journal

Volume 2, Issue 1, January–February 2002, Pages 70-75
The Spine Journal

Case study
Paraplegia after lumbosacral nerve root block: report of three cases,☆☆

https://doi.org/10.1016/S1529-9430(01)00159-0Get rights and content

Abstract

Background context: Lumbar nerve root blocks and epidural steroid injections are frequently employed in the management of degenerative conditions of the lumbar spine, but relatively few papers have been published that address the complications associated with these interventions. Serious complications include epidural abscess, arachnoiditis, epidural hematoma, cerebrospinal fluid fistula and hypersensitivity reaction to injectate. Although transient paraparesis has been described after inadvertent intrathecal injection, an immediate and lasting deficit has not been previously described as sequelae of a nerve root block.

Purpose: We present three cases in which either persisting paraplegia or paraparesis occurred immediately after administration of a lumbar nerve root block and propose a mechanism for this devastating but previously unreported complication.

Study design/setting: Case reports of three patients.

Patient sample: Three patients, two women and one man ranging in age from 42 to 64 years, underwent three procedures performed at three different facilities, in the hands of two different injectionists. In each instance, penetration of the dura was not thought to have occurred. In two procedures the needles were placed transforamenally, one at L3–4 on the left and one at L3–4 on the right, and in the third the needle tip was placed immediately lateral to the S1 nerve root.

Outcome measures: Patient follow-up data from medical office records.

Methods: In each case, needle placement was verified with injection of a contrast media in conjunction with either computerized tomography or biplanar fluoroscopy. No backbleeding or cerebrospinal fluid was encountered upon aspiration in any of the procedures. Magnetic resonance imaging (MRI) was performed within 48 hours of injury in all patients.

Results: In each patient, paraplegia suddenly ensued after instillation of the steroid solution and, in each instance, postprocedure MRI revealed increased signal in the low thoracic spinal cord on T2-weighted imaging consistent with edema. The sudden onset of neurological deficit and the imaging changes noted in the spinal cord point to a vascular explanation for these injuries. We postulate that in these patients the spinal needle either penetrated or caused injury to an abnormally low dominant radiculomedullary artery, a recognized anatomical variant. This vessel, also known as the artery of Adamkiewicz, in 85% of individuals arises between T9 and L2, usually from the left, but in a minority of people may arise from the lower lumbar spine and rarely even from as low as S1. The artery of Adamkiewicz travels with the nerve root through the neural foramen and irrigates the anterior spinal artery. Injury of it or injection of particulate matter into it, as what may happen with the commonly used epidural steroid injectates, may result in infarction of the lower thoracic spinal cord, producing the clinical and imaging findings seen in these three patients.

Conclusions: We present the cases of three patients who had lasting paraplegia or paraparesis after the performance of a nerve root block. We propose that the mechanism for this rare but devastating complication is the concurrence of two uncommon circumstances, the presence of an unusually low origin of the artery of Adamkiewicz and an undetected intraarterial penetration of the procedure needle.

Introduction

Lumbosacral nerve root blocks and epidural steroid injections are frequently used in the management of numerous degenerative conditions of the lumbar spine, including lumbar spinal stenosis, herniated lumbar intervertebral disc disease and facet arthropathy. Relatively few papers, however, have been published that address the complications associated with these interventions. A survey of large series of fluoroscopically guided epidural steroid injections reveals complication rates ranging from 0% to 9.6% [1]. The most commonly reported complication is headache, which is generally self-limited. Serious complications include epidural abscess, arachnoiditis, epidural hematoma, cerebrospinal fluid fistula and hypersensitivity reaction to injectate. Transient paraparesis resulting from epidural steroid injections was previously reported in a case involving inadvertent penetration of the thecal sac by an injection of local anesthetic [2]. We report two cases of paraplegia and one case of serious paraparesis in which neurologic function did not recover after performance of a lumbosacral nerve root block. In addition, we postulate the mechanisms of these neurological injuries. The injuries occurred at three different facilities, in the hands of two different injectionists, and in instances where penetration of the dura was not thought to have occurred. None of the patients had prior symptoms referable to the spinal cord. Magnetic resonance imaging (MRI) was performed within 24 hours of injury in each case revealed signal abnormality in the low thoracic spinal cord on T2-weighted imaging consistent with edema not present on MRIs of any of the three patients before the procedures.

Section snippets

Case 1

A 64-year-old woman presented with 2.5 months of complaints of low back pain, bilateral buttock and leg pain and numbness in her left leg after falling on her back. Four years before presentation, she had undergone laminectomy of L4–5 and a fusion with pedicle screw instrumentation to treat symptoms of progressive low back and leg pain from lumbar spinal stenosis and spondylolisthesis at this level. After surgery, she had good relief of symptoms for 2 years. She then began to complain of back

Discussion

Serious complications of lumbosacral steroid injections include epidural abscess 3, 4, 5, 6, epidural hematoma 7, 8 and hypersensitivity reactions to injectate 9, 10, 11. Neurological dysfunction has been reported as a late complication of dural penetration and subarachnoid injections with development of arachnoiditis 12, 13. Although transient paraparesis has been reported as an immediate sequelae of an intrathecal injection with local anesthetic [2], our report is the first to describe

Acknowledgements

The authors express their gratitude to Peter K. Nelson, MD, Assistant Professor of Radiology (Interventional Neuroradiology), New York University School of Medicine, for his guidance in understanding the relevant vascular anatomy and providing us with some of the images used in our figures.

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    FDA Device/drug status: Approved for this indication (Depo-medrol, Celestone, Lidocaine).

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