Transforaminal steroid injection for lumbar radicular pain proves viable alternative to surgery

Transforaminal injection of steroids is a viable alternative to surgery for lumbar radicular pain due to disc herniation, according to a recent study published in the August issue of Pain Medicine.

Australian researchers examined whether the process of transforaminal injection – the injection of steroids directly onto the affected spinal nerve under radiologic guidance — or the actual agent used was the critical element in determining successful pain relief.

Study methods and parameters

Participants in the study, 150 in all, were randomized into one of five groups receiving either: transforaminal injection of steroids to test effectiveness; transforaminal injection of normal saline to test for an irrigation effect; transforaminal injection of local anesthetic to test its effects; intramuscular injection of steroids to test for a systemic effect; or intramuscular injection of normal saline to test for non-specific or placebo effects.

Patients were adults with pain radiating in the lower limb, with a straight-leg-raise limit of less than 30· and a demonstration of disc herniation by CT or MRI at a segmental level consistent with clinical features.

The study reported that a standard volume and dose were used for each patient and type of injection. The primary outcome measure was the proportion of patients who achieved complete relief of pain or at least 50% relief 1 month after treatment. Secondary outcome measures were function, disability, patient-specified functional outcomes, use of other health care and duration of relief beyond 1 month.

Significant results

The researchers reported that a significantly greater portion of patients who underwent transforaminal injection of steroids (54%) experienced pain relief over patients treated with transforaminal injection of local anesthetic (7%), transforaminal injection of saline (19%), intramuscular steroids (21%) or intramuscular saline (13%).

Relief of pain, according to the study, was corroborated by clinically significant improvements in function and disability, as well as reductions in use of other health care. Outcomes were reported to be equivalent for patients with acute or chronic radicular pain, and 25% maintained relief beyond 12 months.

“In essence, transforaminal injection of steroids is a viable alternative to surgery for lumbar radicular pain due to disc herniation,” stated Nikolai Bogduk, MD, PhD, DSc, the study’s leader, in a press release. “Its immediate yield is modest, but substantial, and is not simply a placebo effect. For long-term efficacy, proof beyond reasonable doubt would require prohibitively large studies.”

Reference:
Ghahreman A, Bogduk N, Ferch R. The Efficacy of Transforaminal Injection of Steroids for the Treatment of Lumbar Radicular Pain. Pain Medicine; Published Online: July 30, 2010 (DOI: 10.1111/j.1526-4637.2010.00908.x); Print Issue Date: August 2010.

The study results are particularly impressive given the stringent study design … from Bogduk’s analysis, one can easily grasp that every third patient will be significantly improved beyond what an intramuscular injection of steroid or a transforaminal injection of normal saline can offer. More to the point, one can observe that one in four patients will retain significant benefit with transforaminal injection of steroids at 12 months, while avoiding the cost of surgery. In the end, this landmark study has vindicated transforaminal steroid injection for lumbar radicular pain as superior to placebo. Further studies are now needed.

– Ray Baker, MD
Author of Accompanying Editorial
Pain Medicine

Reference:
Baker R. Demystifying Lumbar Transforaminal Epidural Steroids: A Seminal Efficacy Study of a Specific Spinal Injection. Pain Medicine. Published Online: July 30, 2010 (DOI: 10.1111/j.1526-4637.2010.00920.x); Print Issue Date: August 2010.

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