This randomized, active control trial shows that carefully selected patients with axial or discogenic chronic low back pain can receive significant pain relief and functional status improvement with lumbar interlaminar epidural injections. Their pain was not caused by disc herniation, facet joints, or the sacroiliac joints. Significant pain relief and functional status improvement of ≥50% were seen in 77% of Group I and 67% of Group II. A better picture emerges when each group was divided into failed and successful outcomes. Significant pain relief and functional status improvement was seen in 84% of the successful outcomes in Group I; 71% in the successful outcomes in Group II. The average procedures per year and average weeks of total relief for the successful outcome patients were: Group I, 3.9 procedures and 40.0 ± 15.6 weeks; Group II, 4.0 procedures and 39.6 ± 12.4 weeks.
The results of this evaluation essentially illustrate that if patients are selected appropriately, lumbar epidural injections provide significant improvement. These results are in line with other studies separating the patients into failed and successful groups.38
The results illustrate that both pain relief and improvement in functional status are clinically and statistically significant. Strict criteria were incorporated into the study and only participating patients judged not to have facet joint or sacroiliac joint pain were included, thus avoiding the criticism that including those with facet joint or sacroiliac joint pain in a study contributes to negative results. As confirmed in this report, epidural injections do not provide long-term relief. But, properly selected patients and appropriate procedures under fluoroscopy can provide long-term relief with judicious use.
Despite multiple publications, there is still significant debate regarding the medical necessity and indications for lumbar epidural injections, either by interlaminar approach, caudal approach, or transforaminal approach. Multiple systematic reviews, guidelines, and other reviews have identified weak indications for epidural injections, namely radicular pain from herniated lumbar intervertebral discs. However, there is a lack of evidence or recommended indications for other conditions. The preliminary report of the current manuscript showed positive results with interlaminar epidural injections.39
Similarly, the previous results with caudal epidurals in appropriately selected patients were positive.38
The results of this evaluation are similar to caudal epidural injections for axial or discogenic pain.38
However, overall relief was superior in the present study, compared to the caudal study.38
Steroids did not have any superiority over local anesthetic alone in either study.
There is a paucity of literature evaluating epidural injections for axial or discogenic pain. The role of caudal epidural injections for axial or discogenic pain, after ruling out facet joint pain or diagnosing it with provocation discography, was evaluated in three studies.38
Only one study51
looked at lumbar interlaminar epidural injections other than the preliminary version of this study.39
evaluated the role of interlaminar epidural steroids showing improvement only at the 3-month follow-up. All of the studies reported modest results.
The mechanism of action of steroids and local anesthetics continues to be debated. Multiple hypothesis have been emerging.76
The evidence shows that steroids, as well as local anesthetics, have significant effects on the modulation of noxious stimulation by various mechanisms. Long-term effects are provided by both local anesthetics and steroids or when in combination, in experimental as well as clinical studies.38
Comparative effectiveness research and evidence-based medicine have been considered as pivotal to health care policy not only in the US, but across the world.10
In general, practical studies conducted in a generally applicable environment are considered more valuable than pragmatic or practical clinical trials with an active control group instead of a placebo group. Practical studies measure effectiveness, which is considered more appropriate than explanatory trials which measure efficacy.90
Thus, this study meets the criteria for a practical clinical trial, specifically in contemporary interventional pain management practices; it meets the appropriate selection criteria and repeats the procedures based upon the return of pain, rather than a predetermined schedule. The procedures were performed under fluoroscopy, only after conservative management had failed. The study also confirms the long-held belief that if the first two procedures do not provide at least a minimum of 3 weeks of relief, the procedures may not provide relief on a long-term basis. This was observed in the failed patients, suggesting that it may be futile to continue to repeat these procedures in these patients, unless there are compelling reasons to do so.
The present study may be criticized for not focusing on a placebo group. However, most studies have utilized inappropriate methodology with placebo groups with reference to interventional techniques.88
The only appropriately designed placebo trial by Ghahreman et al99
showed a lack of significant effect when sodium chloride solution was injected into an inactive structure. Consequently, when sodium chloride solution or other agents such as local anesthetics, which are considered as placebo by some do not yield the same results, this leads to inaccurate methodology and conclusions.100
Some of the other weaknesses include differences in baseline demographic characteristics with respect to weight and sex; however, these differences were not considered to have caused any significant effect on the final results.
The implications of this trial are enormous in the health care arena. Studies with proper methodology in practical settings are not only crucial, but mandatory. Proper application of interventions will improve not only patients’ pain and function and reduce drug use, it may also return them to the workforce; however, by the same token, inappropriate provision of any type of intervention, specifically interventions with substantial expenses, will not provide any benefit. Instead, it can harm the patient, thus depleting resources and reducing access. Similarly, inappropriately performed evaluations in the name of methodology, leading to inaccurate conclusions, may reduce health care expenditures, and will also increase patient suffering and reduce function by impeding access to much needed medical care.