• Epidural steroid shots for back pain had mixed results, an AAN review showed.
• The treatment demonstrated promising short-term benefits for radiculopathy patients.
• In other situations, benefits were unclear or limited.

Epidural steroid injections demonstrated limited efficacy in reducing back pain and disability, according to a systematic review from the American Academy of Neurology (AAN).

In cervical and lumbar radiculopathies, epidural steroids probably reduced short-term pain and disability, and possibly decreased long-term disability, reported Carmel Armon, MD, of Loma Linda University School of Medicine in California, and members of the AAN guidelines subcommittee in Neurology

In lumbar spinal stenosis, epidural steroid injections possibly reduced short-term and long-term disability, but not short-term pain. There was insufficient evidence to determine whether epidural steroids reduced long-term pain.

There was also insufficient evidence to determine the effectiveness of epidural steroids in cervical spinal stenosis.

“Chronic back pain is common and can negatively impact a person’s quality of life, making it difficult to move, sleep, and participate in daily activities,” Armon said in a statement.

“In our review, studies show epidural steroid injections may have limited efficacy,” he continued. “They may modestly reduce pain in some situations for up to 3 months and reduce disability for some people for up to 6 months or more.”

The review updates a 2007 AAN assessment that reported epidural steroids may improve radicular lumbosacral pain between 2 and 6 weeks after the injection, but they did not improve function or reduce the need for surgery.

The new report — directed to neurologists, physiatrists, pain management specialists, orthopedic specialists, neurosurgeons, spine specialists, and primary care clinicians — incorporated new evidence about epidural steroid injections in cervical and lumbar spinal stenosis and radiculopathies, assessing short-term (3 months or less) and long-term (6 months or more) improvements in pain and disability.

The AAN subcommittee searched databases for randomized controlled trials about epidural steroid efficacy published between January 2005 and January 2021, selecting 90 studies for its systematic review. Trials compared epidural shots against placebo or active control. A panel of epidural steroid experts interpreted the evidence in a clinical context.

Most trials focused on lumbar disease; only two class II studies evaluated cervical radiculopathy and none assessed cervical spinal stenosis. Because the trials used a wide variety of efficacy measures, the subcommittee reported differences based on any measure of success as the success rate difference (SRD).

For radiculopathies:

• The SRD for short-term pain was -24.0% (95% CI -34.9 to -12.6), with a number needed to treat (NNT) of 4
• The SRD for short-term disability was -16.0% (95% CI -26.6 to -5.0), with a NNT of 6
• The SRD for long-term disability was -11.1% (95% CI -25.3 to 3.6), with a NNT of 9

In lumbar spinal stenosis:

• The SRD for short-term disability was -26.2% (95% CI -52.4 to 3.6), with a NNT of 4
• The SRD for long-term disability was -11.8% (95% CI -26.9 to 3.8), with a NNT of 8

There’s controversy about the appropriate choice of inactive comparator treatments as a true placebo in clinical trials of epidural steroids, the AAN subcommittee noted. Future studies should use minimal meaningful clinical difference as the measure of efficacy and paraspinal muscle injections of saline as an inactive placebo, the group suggested.

“We found no studies looking at whether repeated treatments are effective or examining the effect of treatment on daily living and returning to work,” noted subcommittee member Pushpa Narayanaswami, MD, of Beth Israel Deaconess Medical Center in Boston. “Future studies should address these gaps.”