Results of 2-year follow-up of a randomized, double-blind, controlled trial of fluoroscopic caudal epidural injections in central spinal stenosis.

Background: Lumbar spinal stenosis is one of the most common causes of low back pain among older adults and can cause significant disability. Despite its prevalence, there is a paucity of literature concerning the treatment of spinal stenosis symptoms. Multiple interventions, including surgery and interventional techniques such as epidural injections and adhesiolysis, are commonly utilized in managing pain related to central spinal stenosis. However, there is a paucity of literature from randomized, controlled trials about the effectiveness of epidural injections for lumbar central spinal stenosis.

Objective: This study sought to assess the effectiveness of caudal epidural injections with or without steroids in providing effective and long-lasting pain relief for the management of chronic low back pain related to lumbar central stenosis.

Study Design: A randomized, double-blind, active-controlled trial.

Methods: One hundred 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, 6 mg (non-particulate betamethasone).

Outcomes Assessment: Multiple outcome measures, including the Numeric Rating Scale (NRS), the Oswestry Disability Index 2.0 (ODI), employment status, and opioid intake were utilized. Assessments were carried out at 3, 6, 12, 18, and 24 months posttreatment. The primary outcome was defined as pain relief and improvement in disability scores of 50% or more. Successful treatment was considered as at least 3 weeks of relief following the first 2 injections, categorizing these patients into a successful group, and others into a failed group.

Results: Significant pain relief and functional status improvement were seen in 51% in Group I and 57% in Group II at the end of 2 years in the successful group when the participants were separated into successful and failed groups. However, overall, significant pain relief and functional status improvement (≥ 50%) was demonstrated in 38% in Group I and 44% in Group II at the end of 2 years. The overall number of procedures for 2 years were 4 in both groups, with 5 procedures on average in the successful groups, and approximately 60 weeks of relief in Group I and 54 weeks of relief in Group II at 2 years in the successful group.

Conclusion: Caudal epidural injections of local anesthetic with or without steroids provide relief in a modest proportion of patients undergoing the treatment and may be considered as an effective treatment for a select group of patients who have chronic function-limiting low back and lower extremity pain secondary to central spinal stenosis.