Ultrasound-guided caudal epidural steroid injection in chronic radicular low back pain: short-term electrophysiologic benefits

OBJECTIVE: To assess the short-term efficacy of ultrasound-guided caudal epidural steroid injections (ESIs) in improving pain, and nerve function as measured by electrophysiological testing in chronic radicular low back pain. METHODS: Patients diagnosed with chronic radicular low back pain were randomized into one of two groups. The injection group (n = 20) underwent a single ultrasound-guided Caudal ESI of 1 ml of 40 mg ml(−1) Triamcinolone Acetonide (Kenacort-A), with local anesthetic. The control group (n = 20) underwent a 12-session physiotherapy program. Both groups were evaluated before and 2 weeks after the intervention using visual analog scale for pain and electrophysiological testing comprising peroneal and tibial terminal motor latencies and F-response latencies and chronodispersion. RESULTS: Both groups showed significant pain reduction on the visual analog scale after the intervention. The injection group showed a significant reduction in F wave chronodispersion post-treatment (<0.01). In the control group, there were no significant differences in F wave parameters pre- and post-treatment (p > 0.05). CONCLUSION: Caudal ESIs were shown to provide short-term improvement of nerve function as evident by improvement in the electrophysiological parameters sensitive to radiculopathy. It was found to be superior to standard physical therapy in this regard. ADVANCES IN KNOWLEDGE: This work shows a novel electrophysiologic evidence of the short-term efficacy ultrasound-guided caudal ESI.