Preliminary results of a randomized, equivalence trial of fluoroscopic caudal epidural injections in managing chronic low back pain: Part 4 - Spinal stenosis

Background: Spinal stenosis is one of the 3 most common diagnoses of low back and leg symptoms which also include disc herniation and degenerative spondylolisthesis. Spinal stenosis is a narrowing of the spinal canal with encroachment on the neural structures by surrounding the bone and soft tissue. In the United States, one of the most commonly performed interventions for managing chronic low back pain are epidural injections, including their use for spinal stenosis. However, there have not been any randomized trials and evidence is limited with regards to the effectiveness of epidural injections in managing chronic function-limiting low back and lower extremity pain secondary to lumbar spinal stenosis. Study Design: A randomized, double-blind, equivalence trial. Setting: An interventional pain management practice, a specialty referral center, a private practice setting in the United States. Objectives: To evaluate the effectiveness of caudal epidural injections with or without steroids in providing effective and long-lasting pain relief in the management of chronic low back pain in spinal stenosis and to evaluate the differences between local anesthetic with or without steroids. Methods: Patients were randomly assigned to one of 2 groups, with Group I patients receiving caudal epidural injections of local anesthetic (lidocaine 0.5%), whereas Group II patients received caudal epidural injections with 0.5% lidocaine 9 mL mixed with 1 mL of steroid. Randomization is being performed by computer-generated random allocation sequence by simple randomization. Outcomes Assessment: Multiple outcome measures were utilized which included the Numeric Rating Scale (NRS), the Oswestry Disability Index 2.0 (ODI), employment status, and opioid intake with assessment at 3 months, 6 months, and 12 months post-treatment. Significant pain relief was defined as 50% or more, whereas significant improvement in disability score was defined as reduction of 40% or more. Results: Significant pain relief (≤ 50%) was demonstrated in 55% to 65% of the patients and functional status improvement with 40% reduction in ODI scores in 55% to 80% of the patients. The overall average procedures per year were 3.4 ± 1.27 in Group I and 2.6 ± 1.35 in Group II with an average total relief per year of 30.3 ± 19.49 weeks in Group I and 23.1 ± 21.36 weeks in Group II over a period of 52 weeks. Limitations: The results of this study are limited by the lack of a placebo group and a preliminary report of 20 patients in each group, even though sample was justified. Conclusion: Caudal epidural injections with or without steroids may be effective in patients with chronic function-limiting low back and lower extremity pain with spinal stenosis in approximately 60% of the patients.