Method Twenty-four patients who had cervical disc herniation in magnetic resonance imaging (MRI) were evaluated. The patients were divided into 2 groups; patients with unilateral cervical radiculopathy in electrodiagnosis (RAD) and patients without definite radiculopathy (HIVD). Twenty six controls without disc herniation were also evaluated. Cervical multifidus muscles from C4-5 to C7-T1 levels were detected in T1 axial MRI, and total cross-sectional area (CSA) of multifidus muscle (TMA) and pure muscle CSA (PMA) were measured.

Results The ratios of TMA in involved side to TMA in uninvolved side (ITMA/UTMA) and PMA in involved side to PMA in uninvolved side (IPMA/UPMA) in HIVD and RAD groups was significantly lower than those in control group especially at C7-T1 level (p＜0.05). We divided the levels of cervical spine into three parts according to lesions found in MRI or electrodiagnosis; above lesion level, at lesion level and below lesion level. Abnormal cases of IPMA/UPMA were not different among levels in HIVD group, but RAD group showed that most of abnormal cases were below lesion (60%).

Conclusion Asymmetric multifidus atrophy was seen in patients with cervical disc herniation and radiculopathy. The ratio of pure muscle CSA between involved and uninvolved sides might be a useful parameter to differentiate patients with unilateral cervical radiculopathy from patients without radiculopathy.

Objective: To increase the accuracy and consistency in determining the level of radiculopathy by a needle electromyography (EMG) of multifidus muscle.

Method: We performed the EMGs on 29 patients with a low back pain to investigate an evidence of radiculopathy. All patients had the herniated nucleus pulposus (HNP) by a myelography, CT or MRI. The exclusion criteria were the patients with a scoliosis, spondylolisthesis or history of back surgery. We examined 5 points (P 1∼5) of the lumbosacral paraspinal muscles according to the paraspinal mapping by Haig et al and scored from 0∼4 according to the degree of abnormalities. The scores according to the points were correlated with the segments of radiculopathy and the levels of HNP.

Result: The maximal mean scores were 1.80⁑0.83 at P2 and 2.00⁑1.41 at P3 in a lumbar (L) 3, 4 radiculopathy, 2.00⁑0.56 at P5 in a L5 radiculopathy, and 2.13⁑0.64 at P4 and 2.63⁑0.51 at P5 in a S1 radiculopathy. The sensitivity/specificity was high at P2, P3 in a L3, 4 radiculopathy, at P4 in a L5 radiculopathy, at P5 in a S1 radiculopathy.

Conclusion: The results suggest that the localization of lumbosacral radiculopathy by a needle EMG of multifidus muscles provides an easy accessibility, better accuracy and consistency to determine the level of radiculopathy.