Needle Electromyographic Findings in L5 Radiculopathy Caused by L4-5 Intervertebral Disc Displacement

J Korean Assoc EMG Electrodiagn Med 2009;11(2):61-65.
Published online December 31, 2009.

Abstract

Objectives: To determine selecting ideal muscles in evaluating L5 radiculopathy through electrophysiologicstudy.
Methods: Electrophysiologic cases which were confirmed for L5 radiculopathies were studied, excludingperipheral neuropathy other than L5 radiculopathy, myelopahty or recent spine surgery less than 3 years.Twenty-seven patients presented with clinical findings of L5 radiculopathy included. The clinical diagnosisof L5 radiculopathy and intervertebral disc displacement in the 4th and 5th lumbar level was confirmedby magnetic resonance imaging (MRI). Patients with peripheral neuropathy other than L5 radiculopathy,myelopathy or recent spine surgery less than 3 years were excluded. We performed electrophysiologicstudies in muscles defined by two different categories: paravertebral, proximal and distal groups.
Results: Muscles of extensor hallucis longus (79%), extensor digitorum longus (75%), tibialis anterior(70%), paravertebral muscle (62%), peroneus longus (62%), tensor fascia lata (60%), gluteus medius(38%) and lateral head of gastrocnemius (33%) showed abnormal findings in needle electromyography.Including even one abnormal finding in any muscle in each group, the distal group showed the highestrate of abnormalities such as 100% whereas proximal and paravertebral group showed each rate as 68%and 65% in order. Tensor fascia lata muscle and extensor hallucis longus muscle showed the highest rateof abnormalities in each group.
Conclusion: We propose that tensor fascia lata in proximal and extensor hallucis longus in distal musclegroups should be selected in L5 radiculopathy.

Key Words: Radiculopathy, Electromyography, Muscle, Intervertebral disc displacement