Cervical Multifidus Muscle Atrophy in Patients with Unilateral Cervical Radiculopathy

ABSTRACT

OBJECTIVE: To assess the atrophy of cervical multifidus muscles in patients with unilateral cervical disc herniation or radiculopathy quantitatively and to investigate whether asymmetric muscle atrophy has the relationship with the severity of cervical disc herniation or radiculopathy. 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.