Results Summary
What was the research about?
Lumbar spinal stenosis is a narrowing of space in the spine and is common in older adults. The narrowing of the spinal space can result in pressure on the nerves in the lower back, which can cause leg pain and make it difficult to do everyday activities.
Doctors sometimes inject medicines into the epidural space of the lower back to treat lumbar spinal stenosis. The epidural space is inside the boney canal of the spine but outside the spinal cord. The shots can contain two types of medicines. Steroids reduce swelling. Numbing medicines, such as lidocaine, can offer short-term pain relief.
In an earlier study, researchers compared two treatments for lumbar spinal stenosis in older patients over a nine-week period. Each patient got four shots that contained either
- A steroid and lidocaine
- Only lidocaine
In this study, the research team continued to follow patients for one year.
What were the results?
After one year, no matter which type of shot,
- Patients’ leg pain decreased about the same amount.
- Patients’ ability to do everyday activities improved similarly.
- The percentage of patients who needed other treatments for pain was similar.
Between the third and fourth shots, patients could switch to the other type of shot. Of the 150 patients who switched, 87 percent switched because their pain hadn’t decreased. Fewer patients switched groups if they had started with steroid shots than if they had started with lidocaine-only shots. At the end of the study, patients who switched to steroid plus lidocaine or lidocaine-only shots noted similar improvements in pain and physical ability.
Who was in the study?
The study included 400 adults at least 50 years old with lumbar spinal stenosis. The research team recruited patients referred for epidural steroid shots at 16 clinics across the United States. Patients had moderate to severe leg pain and impaired physical ability.
What did the research team do?
In the earlier study, the research team assigned patients by chance to receive one of two types of epidural shots. At the start of that study, each patient received one type of shot and could choose to get another three weeks later. At six and nine weeks, patients could then decide to switch to receive the other type of shot. Patients who didn’t switch could receive the same type of shot up to four times.
In this study, the research team followed patients for a longer time. They evaluated patients at various times during the one-year period after their first shot. Using a survey, they asked patients about
- Leg pain
- Ability to do everyday activities
- Other treatments received during the study
At six weeks, the team also noted how many patients switched to the other type of shots.
When planning and conducting the study, the research team worked with patients with lumbar spinal stenosis, doctors, and policy makers.
What were the limits of the study?
Patients in the study were older adults who had one type of lumbar spinal stenosis. The results may not apply to younger patients or those with other types of spinal stenosis. The doses of the epidural medicines and the type of steroid varied within each group, which may have affected the results. The team compared steroid shots with just lidocaine, which has some pain-relieving effects. As a result, the study doesn’t show how epidural steroids compare with no treatment. Although fewer patients switched groups if they started with steroid shots, the research team noted that this difference occurred at only one study location.
Future studies could look at younger adults or people with other types of spinal stenosis. Other research could look at just one dose of steroid shots or compare steroid shots with no treatment.
How can people use the results?
Doctors and patients can use the results to discuss treatment options for lumbar spinal stenosis. Patients who got both types of shots showed similar improvement at one year. This result suggests that adding a steroid to lidocaine shots doesn’t make the treatment more effective.
Professional Abstract
Objective
To compare the long-term effects of epidural injections of a corticosteroid plus lidocaine versus lidocaine alone in older adults with central lumbar spinal stenosis (LSS) in an extension and expansion of the Lumbar Epidural Steroid injections for Spinal stenosis (LESS) study
Study Design
| Design Elements | Description |
|---|---|
| Design | Randomized controlled trial |
| Population | 400 adults, ages 50 and older, with moderate to severe leg pain and disability due to central LSS |
| Interventions/ Comparators |
|
| Outcomes |
Primary: leg pain, disability Secondary: opioid use, physical therapy, spine surgery, crossover to other treatment group |
| Timeframe | 12-month follow-up for the primary outcomes |
The LESS study, funded by the Agency for Healthcare Research and Quality, compared the effects of epidural injection of a corticosteroid plus lidocaine with lidocaine alone in older adults with LSS for up to 12 months. In the LESS study, researchers recruited 400 older adults with LSS referred for epidural injections at 16 sites across the United States. The physician chose the dose of lidocaine, the type and dose of corticosteroid, and the injection technique (interlaminar or transforaminal). Patients received one epidural injection according to their assigned group at study enrollment and again after three, six, and nine weeks at the discretion of the patient and clinician. Researchers assessed disability and leg pain at baseline and two, three, and six weeks and continued follow-up out to 12 months when feasible within the three-year duration of LESS.
In this extension study, researchers assessed leg pain, disability, and use of other treatments at 12‑month follow-up for all remaining patients and identified if certain patient characteristics predicted benefit from epidural steroid injections. During the 12-month follow-up, patients completed questionnaires about use of medication, opioids, physical therapy, and spine surgery. Researchers then analyzed the results for the 150 patients who crossed over from one group to the other at six weeks, with 87% of those reporting inadequate pain relief as their rationale. Researchers also examined 21 patient characteristics as potentially predictive of treatment response.
Patients with LSS, clinicians, and healthcare policy makers provided input throughout the study.
Results
At 12 months, patients in both groups reported similar decreases in leg pain and reduction in levels of disability, and the two groups did not differ in the percentage of patients receiving opioids, physical therapy, or spine surgery. Further, leg pain and disability were similar for patients who crossed over to the corticosteroid plus lidocaine group or to the lidocaine-only group. The crossover rate was higher in the lidocaine-only group than in the corticosteroid plus lidocaine group (45% versus 30%, p=0.003). However, one study site accounted for the difference in the crossover rate.
No baseline patient characteristic emerged as a clear and strong predictor of a benefit from epidural injection of corticosteroid and lidocaine versus lidocaine alone.
Limitations
All patients were at least 50 years old and had central LSS, so the results may not apply to younger patients or those with other types of spinal stenosis. Treatment, including the epidural medications and injection technique, varied within the groups and may have affected outcomes. The comparison group received lidocaine, which has short-term analgesic effects. As a result, the findings do not indicate whether epidural corticosteroids are more effective than no treatment.
Conclusions and Relevance
In this study, older patients with central LSS receiving either corticosteroids plus lidocaine or lidocaine alone noted reduced leg pain and disability at 12 months. However, the reductions were similar in both groups as was seen in the LESS study at six weeks.
These results may help physicians and patients decide on a treatment for central LSS. The study’s findings suggest that epidural injections of a corticosteroid plus lidocaine have limited, if any, long-term benefit over lidocaine alone.
Future Research Needs
Future research could evaluate epidural shots in younger adults or patients with other types of spinal stenosis. Additional studies could evaluate a single type or dose of corticosteroids or only one epidural injection technique (interlaminar or transforaminal). Future studies could also compare epidural corticosteroid and sham injections, in which no medicine is present.
Final Research Report
View this project's final research report.
Journal Citations
Results of This Project
Related Journal Citations
Peer-Review Summary
Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study.
The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments.
Reviewers’ comments and the investigator’s changes in response included the following:
- The reviewers requested that the report better describe the study’s adherence to PCORI’s Methodology Standards. In response, the awardee added explanations of its work in patient and stakeholder engagement. The investigator also explained the relationship of the Lumbar Epidural Steroid Injections for Spinal Stenosis Extended Research (LESSER) study to the previously funded Lumbar Epidural Steroid Injections for Spinal Stenosis (LESS) study, including differences in the methods for patient recruitment. The investigator also explained their choices regarding the treatment of missing data.
- The awardee responded to reviewers’ recommendations for analyses of heterogeneity of treatment effects. The investigator described the analyses it conducted that compared lidocaine versus corticosteroid injections. The investigator added details about these analyses and noted that more detail could be found in its published paper.
- Given the long-term nature of the study, the reviewers questioned the awardee’s focus on findings related to three and six week outcomes. The awardees explained that there were three and six week limits to the predictors of outcome analysis due to the findings of no difference at six weeks and the lack of evidence for long-term benefits at 12 months.
- The awardee added a limitation, acknowledging that the design of the original LESS study, from which the current LESSER study came, addressed the effectiveness of corticosteroid versus lidocaine injections and was not powered for secondary analyses. Therefore, the awardee suggested considering those analyses tentative and hypothesis generating.
- The investigator clarified the conclusions, stating that although patients felt that the decision aid’s material was clear and helpful, there was no evidence that using the aid changed patient behavior.