Background of Epidural Steroid Injections: Where Should We Go From Here? Ameet Nagpal, MD, MS, MEd Assistant Professor/Clinical, Department of Anesthesiology University of Texas Health Science Center at San Antonio
No relevant financial disclosures
Background 130% increase in performance of ESIs was noted in Medicare beneficiaries between 2000 and 2011 1 665% increase in the performance of lumbosacral transforaminal ESIs during this time period 1 Because of several catastrophic outcomes leading to paralyses, blindness, aseptic and septic meningitides, and deaths, the utility of ESIs has been called into question 2-6 1. Manchikanti L, Pampati V, Falco FJ, Hirsch JA. Assessment of the growth of epidural injections in the Medicare population from 2000 to 2011. Pain Physician 2013; 16(4):E349-64. 2. Smuck M, Fuller BJ, Chiodo A, Benny B, Singaracharlu B, Tong H, Ho S. Accuracy of intermittent fluoroscopy to detect intravascular injection during transforaminal epidural injections. Spine 2008; 33:E205-210. 3. Chang Chien, GC, Candido, K. D., and Knezevic, N. N. Digital subtraction angiography does not reliably prevent paraplegia associated with lumbar transforaminal epidural steroid injection. Pain Physician 2012; 15:515-523. 4. Atluri S, Glaser SE, Shah RV, Sudarshan G. Needle position analysis in cases of paralysis from transforaminal epidurals:consider alternative approaches to traditional technique. Pain Physician 2013;16:321-334. 5. Kennedy, D. J., Dreyfuss, P., Aprill, C. N. and Bogduk, N. Paraplegia Following Image-Guided Transforaminal Lumbar Spine Epidural Steroid Injection: Two Case Reports. Pain Medicine 2009; 10: 1389 1394. 6. Centers for Disease Control and Prevention (CDC). Multistate outbreak of fungal infection associated with injection of methylprednisolone acetate solution from a single compounding pharmacy United States, 2012. MMWR Morb Mortal Wkly Rep 2012; 61(41):839-42.
Let s Start Asking Questions 34 year old male presents to your clinic with pain radiating down the right lower extremity into his great toe. Straight leg raise is positive. Statement: An MRI should be performed before performing an epidural steroid injection. ARS: A. Yes B. No
Poll: Statement: An MRI should be performed before performing an epidural steroid injection.
MRI Prior To Epidural Steroid Injection
MRI Prior to Epidural Steroid Injection 65 patients received ESI with practitioner blinded to MRI results (group 1), 67 received ESI after review of MRI by practitioner (group 2) No statistically significant difference in leg or back pain score between groups at 1 month or 3 months At 1 month: Group 2 had decreased medication consumption but not at 3 months At 1 and 3 months: Group 2 had improved global perceived effect No differences in success rates
Why Would That Be? Mean levels of spread: 1.13 cephalad and 0.6 caudad
Why Would That Be? More data Any volume greater than 0.5mL (contrast) is no longer diagnostically sensitive to one level in 30% of cases 1.5mL 87% 2.5mL 90%
Should An MRI Be Performed For Safety? No studies exist on this topic In the Cohen study, no complications related to the practitioner not viewing the MRI were reported
Back To The Case 34 year old male presents to your clinic with pain radiating down the right lower extremity into his great toe. Straight leg raise is positive. An MRI is performed and reveals a right paracentral disc protrusion at L4/L5 impinging on the traversing L5 nerve root. ARS Question: Which level should the ESI be performed at? A. L4/L5 B. L5/S1
Poll: Which level should the ESI be performed at?
Pathology vs. Nerve Root Compared performing an ESI at the nerve root vs. at the level of pathology No statistically significant difference in effective treatment (p=0.056, odds ratio 10.483 in favor of the preganglionic approach, AKA injected at the level of the disc pathology) 13 patients in one arm, 20 in the other Effectiveness defined as: patient satisfaction 3 or 4 on 0-5 scale and VAS > 50% relief at 2 weeks post-procedure
Pathology vs. Nerve Root Compared performing an ESI at the nerve root vs. at the level of pathology No difference in compared means in: VAS, RMDQ, and patient satisfaction index Both groups had statistically significant improvements in VAS
Also, don t forget Mean levels of spread: 1.13 cephalad and 0.6 caudad 1.5mL 87% 2.5mL 90%
Back To The Case 34 year old male presents to your clinic with pain radiating down the right lower extremity into his great toe. Straight leg raise is positive. MRI is not approved by the patient s insurance, however an EMG would be. ARS Question: Would a positive EMG impact your decision making? A. Yes B. No
Can EMG Predict ESI Success? 3 groups of patients received ESIs: those who had positive EMG, negative EMG, and equivocal EMG Success defined as > 50% improvement in VAS
Back To The Case 34 year old male presents to your clinic with pain radiating down the right lower extremity into his great toe. Straight leg raise is positive. MRI is not performed. EMG is negative for radiculopathy. ARS Question: Does the patient have a radiculopathy? A. Yes B. No
Poll: Does the patient have a radiculopathy?
EMG Sensitivity and Specificity for Radiculopathy In the most stringent studies available 1,2 : Sensitivity: 44-47.8%; Specificity: 86-87.5% EMG is probably best utilized as a confirmatory test, not a screening test, for radiculopathy 20 1. Coster S., de Bruijn S.F., and Tavy D.L.: Diagnostic Value of history, physical examination, and needle electromyography in diagnosing lumbosacral radiculopathy. J Neurol 2010; 257: pp. 332-337 2. Haig A.J., Tong H.C., Yamakawa K.S., et al: The sensitivity and specificity of electrodiagnostic testing for the clinical syndrome of lumbar spinal stenosis. Spine 2005; 30: pp. 2667-2676
Back To Our Case 34 year old male presents to your clinic with pain radiating down the right lower extremity into his great toe. Straight leg raise is negative. An MRI is performed and reveals a right paracentral disc protrusion at L4/L5 impinging on the traversing L5 nerve root. ARS Question: Does the patient have a radiculopathy? A. Yes B. No
Poll: Does the patient have a radiculopathy?
Sensitivity of Straight Leg Raise Test
Seated Slumped Root Test vs. Straight Leg Raise Patients with radiculopathy confirmed with > 4 weeks of radicular pain with corroborating MRI findings and myotomal weakness and/or reflex changes Sensitivity of seated slumped root: 0.41; supine straight leg: 0.67. But
Overlapping Confidence Intervals!
Conclusions MRI results are not predictive of success with epidural steroid injections There is a slight trend towards superior results with performing ESI at the level of the disc pathology rather than directly on the irritated nerve root but this is not statistically significant EMG is specific but not sensitive for diagnosing lumbar radiculopathy Straight leg raise has variable sensitivity and is not a good screening test for radiculopathy