The role of transforaminal epidural steroid injections on H-reflex parameters in unilateral S1 radiculopathy

Abstract

We aimed to evaluate whether transforaminal epidural steroid injections (TFESI) impact on H-reflex (HR) parameters in unilateral S1 radiculopathy, correlation between changes in HR parameters and treatment outcomes. A total of 34 patients with radicular low back pain, lumbar disc herniation and unilateral S1 root compression detected at L5-S1 level were included in this prospective study. The study was carried out in three stages. Before TFESI, patients were evaluated clinically (with motor and sensory examination, achilles reflex, fingertip-to-floor and straight leg raise test, numeric rating scale for pain, Oswestry Disability Index and Beck Depression Inventory) and radiologically by the first clinician. A second clinician performed nerve conduction studies and late responses. A third clinician carried out TFESI. 1st hour, 3rd week, 3rd month post-TFESI evaluations were carried out as they were before the treatment. In all follow-ups, there was a significant decrease in the HR latency, H-M interval in the affected side, and in difference between both sides in terms of HR latency after treatment, when compared to pre-treatment ( P < 0.05). On the 1st hour post-TFESI, HR was back to normal in 95.7% of 23 patients who had abnormal HR, and this recovery continued well into the 3rd month post-TFESI in 78.3%. No significant correlation was detected between HR changes and clinical recovery. Changes in HR latency were found to be correlated with the stage of nerve root compression. It was found that recovery in HR latency parameters can be achieved in addition to the clinical parameters after TFESI. The results are notable since they can shed light on future studies, which will investigate the role of HR in evaluating treatment outcomes and its predictive value. In cases where clinical and radiological findings are insufficient or controversial, changes in HR latency can be suggestive of the stage of nerve root compression.