Comparison of sensitivities of macro EMG and concentric needle EMG in L4 radiculopathy

The purpose of this study was to compare the sensitivities of macro EMG (mEMG) and concentric needle EMG (cnEMG) in showing abnormality in L4 radiculopathy. We evaluated 23 patients with clinically and radiologically proven L4 root lesions. Among these patients, 21 (92%) had cnEMG abnormalities. Out of 21 patients with cnEMG abnormality, 3 (14%) had fibrillations and positive sharp waves, 8 (38%) had interference pattern abnormality and all of them had motor unit potential (MUP) abnormality on quantitative MUP analysis. Seventeen patients (74%) had mEMG abnormality. Diagnostic yield of cnEMG is higher than mEMG in L4 radiculopathy. mEMG may not contribute much to the diagnosis of lumbar radiculopathy.