BACKGROUND: Post lumbar surgery syndrome represents a cluster of nomenclature and syndromes following spine surgery wherein the expectations of the patient and spine surgeon are not met, with persistent pain following lumbar surgery. Multiple causes have been speculated to cause pain after lumbar surgery. Epidural steroid injections are most commonly used in managing post surgical pain in the lumbar spine. However, there is a paucity of evidence of epidural injections in managing chronic low back pain with or without lower extremity pain in post surgery syndrome. STUDY DESIGN: A randomized, double-blind, active controlled 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 in patients with chronic low back and lower extremity pain after surgical intervention with post lumbar surgery syndrome. METHODS: One-hundred forty patients were randomly assigned to one of 2 groups; Group I patients received caudal epidural injections with local anesthetic (lidocaine 0.5%), whereas Group II patients received caudal epidural injections with 0.5% lidocaine 9 mL mixed with 1 mL of 6 mg non-particulate Celestone. Randomization was 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 and disability reduction were described as 50% or more reduction in scores from baseline. RESULTS: Combined pain relief (>/=50%) and disability reduction was recorded in 53% of the patients in the local anesthetic group, and 59% of patients in the local anesthetic and steroid group with no significant differences noted with or without steroid over a period of one-year. However, the data from the successful group showed improvement in 70% of patients in Group I and 75% of patients in Group II. The average procedures per year were 4 with an average total relief per year of 38.1 ± 14.5 weeks in Group I and 38.4 ± 13.2 weeks in Group II over a period of 52 weeks in the successful group. LIMITATIONS: The results of this study are limited by the lack of a placebo group and one-year outcomes. CONCLUSION: Caudal epidural injections in chronic function-limiting low back pain in post surgery syndrome without facet joint pain may be effective in a significant proportion of patients with improvement in functional status and significant pain relief. CLINICAL TRIAL: NCT00370799.