Effect of caudal epidural steroid injection on electrodiagnostic parameters in patients with lumbosacral radiculopathy: A double-blinded randomized controlled trial

Objectives: The aim is to compare the caudal epidural steroid injection (CESI) and caudal epidural normal saline injection (CENSI) injection in discogenic lumbosacral radiculopathy using nerve conduction study and subjective questionnaires-based outcome. Materials and Methods: Two postrandomized groups of lumbosacral radiculopathy patients ( n = 40) were treated with either CESI (case group) or CENSI (control group), both under ultrasonography guidance. The outcomes were assessed at 2 weeks by electrophysiological parameters of lower-extremity nerves, namely, compound motor action potentials and F-wave parameters of common peroneal nerve and posterior tibial nerve. We also used subjective scales like the Oswestry low back pain disability index (OLBPDI) and the Numerical Rating Scale (NRS). Results: Delayed F-wave min latency was the single electrophysiological parameter that correlated well with established lumbosacral radiculopathy at the baseline. On subsequent evaluation after 2 weeks of epidural injection, both treatment groups were significantly effective in reducing pain and disability (OLBPDI and NRS). However, corticosteroid injection showed some evidence of electrophysiological superiority in comparing pre-post values of both lower-extremity nerves regarding amplitude, latency, and conduction velocity, but they were not statistically significant. Conclusion: The flushing effect of normal saline injected epidurally significantly improves the electrophysiological parameters of lumbosacral radiculopathy patients. Both clinical outcome and electrophysiological outcomes were comparable in both CESI (case) and CENSI (control) groups.