H Reflex and It's Relation to the Findings of Needle Electromyography in S1 Radiculopathy

J Korean Assoc EMG Electrodiagn Med 2004;6(2):156-159.
Published online May 10, 2004.

Abstract

Objective: To evaluate the relation between H reflex and findings of needle electromyography in patients with S1 radiculopathy. Method: Electrophysiologic data of 41 patients (male 23, female 18, average age 53±17.2) who had been diagnosed as S1 radiculopathy were obtained. The S1 radiculopathy was confirmed by H reflex and needle electromyography study. The H reflex findings were classified into 3 groups: absent, delayed, normal. Needle electromyography findings were classified into 3 groups: normal; type 1 abnormality, abnormal spontaneous activities and abnormal motor unit potentials; type 2 abnormality, abnormal motor unit potentials only. The Mann-Whitney U test was used for statistical analysis. Results: Out of 41 patients with S1 radiculopathy, H reflex was unobtainable in 20 patients, of delayed latency in 7 patients and of normal findings in 14 patients. Type 1, 2 abnormalities and normal needle electromyography findings were shown in 7, 12, 1 cases in 20 patients with absent H reflex, respectively, and 2, 3, 2 cases in 7 patients with delayed H reflex, respectively. Even in 14 patients with normal H reflex, 7 patients showed type 1 abnormality and 7 patients showed type 2 abnormality. Based on the results, there is no relation between H reflex and needle electromyography. (p>0.05) Conclusion: Abnormal H reflex is not always present in S1 radiculopathy. Abnormality of H reflex might be related to the involvement of motor or sensory root according to the degree or direction of herniated nucleus pulposus.

Key Words: S1 radiculopathy, H reflex, Needle electromyography