Central Canal Spinal Stenosis
Adding corticosteroids to epidural lidocaine injections in patients with central canal lumbar spinal stenosis did not increase efficacy, raising the question of whether steroids should be used in this setting, researchers reported in the New England Journal of Medicine.1
“Epidural steroid injections do not offer any substantial advantage over lidocaine injections for patients with spinal stenosis yet carry additional risk,” said senior author Jeffrey G. Jarvik, MD, MPH, Professor, Radiology, Neurological Surgery and Health Services, Adjunct Professor, Pharmacy and Orthopedics & Sports Medicine, and Director, Comparative Effectiveness, Cost and Outcomes Research Center, University of Washington, Seattle, Washington.
“We hope that the impact of our study will be to provide rigorous evidence to health care providers and patients so that they can have better informed conversations about these sort of injections,” Dr. Jarvik said. “Ultimately, the decision to proceed with an epidural injection, whether lidocaine alone or in combination with corticosteroid, should be made jointly between patients and their physicians after weighing the potential risks and benefits. Our study provides evidence needed to make those decisions.”
“It is already well accepted that central canal stenosis is a fairly weak indication for epidural steroids compared to other diagnoses such as lumbar radiculopathy or foraminal stenosis,” commented Steven H. Richeimer, MD, Chief, Division of Pain Medicine, Keck School of Medicine, University of Southern California, Los Angeles. “This study continues the line of thinking, which has evolved over the last several years, that central canal stenosis is not a good indication for epidural steroids.”
Similar Efficacy Found
The study—led by Janna Friedly, MD, of Harborview Medical Center in Seattle—is the largest to date on this topic. It involved 400 patients with stenosis of the lumbar central spinal canal and resultant leg pain (average pain score = 4 on a scale from 1 to 10). The patients were randomized to receive fluoroscopically guided epidural injections with either lidocaine alone (n=200) or lidocaine plus glucocorticoids (n=200). The patients were unaware to which treatment group they were assigned.
Although both treatments were associated with significant improvements in pain and scores on the Roland–Morris Disability Questionnaire over baseline levels, the between-group differences were not statistically significant (Table). Patients in the glucocorticoid-lidocaine group reported significantly greater treatment satisfaction and greater reductions in depressive symptoms, but no difference in scores on the Brief Pain Inventory, Swiss Spinal Stenosis Questionnaire symptoms and physical function, EQ-5D, or Generalized Anxiety Disorder 7 scales compared with the lidocaine-alone group.
Adding Steroids Raises Risk for Adverse Events
Patients in the glucocorticoid–lidocaine group were significantly more likely to report one or more adverse events (21.5% vs. 15.5%; P=0.08) and had more adverse events on average per person compared with the lidocaine-alone group (0.29 vs. 0.17; P=0.02). In both groups, use of the transforaminal injection was linked to a higher rate of adverse events than interlaminar injection.
More Rigorous Comparative Studies Are Needed
The study raises an important question: how do these 2 interventions compare against placebo? “We need to take a closer look to see if local anesthetic injections for central canal stenosis accomplish something more than placebo,” Dr. Richeimer said.
When asked why steroid injections are used for central canal stenosis despite little evidence to support their use, Dr. Richeimer said that “patients are often aggressively looking for alternatives to surgery, and in an effort to find patients an alternative, these [injections] are often offered even if the response rate is not fantastic.”
Dr. Jarvik said that “epidural steroid injections are not an isolated case when it comes to medical interventions that have disseminated without a strong evidence basis. Clinical practice guidelines used to guide therapeutic decisions often lack high-quality evidence to support recommendations,” he said.2 “Another example of an intervention that disseminated without much rigorous evidence is vertebroplasty. Our group helped to conduct a trial of this intervention … with similar results—the intervention that most people were convinced worked turned out to be no better than lidocaine. In both trials, both the intervention and control groups improved,” he added.3
“Interventions such as epidural steroid injections are attractive because anecdotal evidence and smaller, less well-controlled studies support their use. Our study emphasizes that rigorous, controlled comparative-effectiveness studies are necessary to understand how well a medical intervention will perform,” Dr. Jarvik said.
“If a patient asks about a procedure such as an epidural steroid injection, be prepared to discuss the best available evidence for that procedure including the small magnitude of benefit and possibility of adverse effects, and consider offering a lidocaine-only injection as an alternative,” Dr. Jarvik concluded.