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Safety of Interlaminar and Transforaminal Epidural Steroid Injections

Chen, Boqing MD, PhD; Stitik, Todd P. MD; Foye, Patrick M. MD

doi: 10.1213/ANE.0000000000000009
Letters to the Editor: Letter to the Editor
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Physical Medicine and Rehabilitation, New Jersey Medical School, Metuchen, New Jersey, boqing_chen@yahoo.com

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To the Editor

Based on the results of their study comparing the efficacy of lumbar epidural steroid injection via a parasagittal interlaminar approach with that following a midline interlaminar approach, Ghai et al.1 concluded that a lumbar transforaminal epidural steroid injection (TFESI) targeting the “safe triangle” does not guarantee safety due to potential radiculomedullary artery (Adamkiewicz artery) injury. While we agree with this conclusion, we respectfully disagree with the authors’ implied opinion that the parasagittal interlaminar approach may be safer than the approach following traditional TFESIs.

At least 3 cases of lumbar paraplegia have been reported after interlaminar lumbar epidural steroid injections.2 The proposed mechanism is similar to that for paraplegia from a lumbar TFESI in which the epidural needle injured or penetrated the radiculomedullary artery and particulate corticosteroid was injected into the spinal canal with resultant spinal cord embolism and subsequent paraplegia. In fact, anatomic studies have demonstrated that after the radiculomedullary arteries enter the neuroforamina near the anterior aspect of the dorsal root ganglion and exiting nerve root,3,4 they often travel a distance superiorly and laterally in the lateral epidural space joining the anterior spinal artery which ultimately supplies the anterior 2/3 of the spinal cord. In addition, in about 63% of cadavers studied, there is a posterior branch of the radiculomedullary artery which supplies the dorsal aspect of the cauda equina.5 It is conceivable that the epidural needle might encounter the radiculomedullary artery in the lateral or in the midline posterior epidural space.

In light of the radiculomedullary artery anatomical positions inside the spinal canal as described above, neither midline nor parasagittal interlaminar lumbar epidural steroid injections are completely risk-free with respect to potential needle vascular injury and paraplegia, particularly if particulate corticosteroids are used, as has been determined for TFESIs. Furthermore, Kambin’s triangle approach for TFESIs might be the safest of all approaches.6–8

Boqing Chen, MD, PhD

Todd P. Stitik, MD

Patrick M. Foye, MD

Physical Medicine and Rehabilitation New Jersey Medical School Metuchen New Jersey, boqing_chen@yahoo.com

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REFERENCES

1. Ghai B, Vadaje KS, Wig J, Dhillon MS. Lateral parasagittal versus midline interlaminar lumbar epidural steroid injection for management of low back pain with lumbosacral radicular pain: a double-blind, randomized study. Anesth Analg. 2013;117:219–27
2. Thefenne L, Dubecq C, Zing E, Rogez D, Soula M, Escobar E, Defuentes G, Lapeyre E, Berets O. A rare case of paraplegia complicating a lumbar epidural infiltration. Ann Phys Rehabil Med. 2010;53:575–83
3. Kroszczynski AC, Kohan K, Kurowski M, Olson TR, Downie SA. Intraforaminal location of thoracolumbar anterior medullary arteries. Pain Med. 2013;14:808–12
4. Murthy NS, Maus TP, Behrns CL. Intraforaminal location of the great anterior radiculomedullary artery (artery of Adamkiewicz): a retrospective review. Pain Med. 2010;11:1756–64
5. Rodriguez-Baeza A, Muset-Lara A, Rodriguez-Pazos M, Domenech-Mateu JM. The arterial supply of the human spinal cord: a new approach to the arteria radicularis magna of Adamkiewicz. Acta Neurochir (Wien). 1991;109:57–62
6. Park JW, Nam HS, Cho SK, Jung HJ, Lee BJ, Park Y. Kambin’s Triangle Approach of Lumbar Transforaminal Epidural Injection with Spinal Stenosis. Ann Rehabil Med. 2011;35:833–43
7. Glaser SE, Shah RV. Root cause analysis of paraplegia following transforaminal epidural steroid injections: the ‘unsafe’ triangle. Pain Physician. 2010;13:237–44
8. Zhu J, Falco FJ, Formoso F, Onyewu O, Irwin FL. Alternative approach for lumbar transforaminal epidural steroid injections. Pain Physician. 2011;14:331–41
© 2014 International Anesthesia Research Society