S78. MRI assessment of neck muscles in patients with unilateral cervical radiculopathy patients

Introduction Several recent studies have investigated the changes of multifidus muscles in patients with chronic neck pain. Also, the longus coli muscle, one of the deep cervical flexor muscles, showed smaller cross sectional area (CSA) in patients with chronic neck pain in comparison with healthy people. To our knowledge, there is no study investigating the association between morphological features of cervical paravertebral muscles in electrodiagnosed cervical radiculopathy patients. In this study, we investigate the change in CSA and composition of the cervical flexor and multifidus muscles using the digital data from MRIs of patients with electrodiagnosed cervical radiculopathy. Methods Twenty-four patients with unilateral cervical radicular pain who had cervical MRI and EMG examinations between 1 January 2015 and 2016 were retrospectively analysed. The inclusion criteria were as follows: (1) patients with the symptoms of unilateral cervical pain or referral to one upper limb, (2) diagnosis of cervical radiculopathy in EMG. Exclusion criteria included: (1) a history of cervical surgery; (2) a history of spinal fracture or injuries; (3) primary or metastatic spinal tumor. Axial slice at the level of C4-5 mid disc level image was selected to calculate the muscle CSA, with their maximal CSAs. Total CSA and functional CSA measurements of the bilateral longus colli, sternocleidomastoid and multifidus muscles were measured by using Image J (version 1.43, National Institutes of Health, Bethesda, Maryland). All muscle measurements were acquired by one investigators. Functional CSA measurement was obtained by using threshold method (including only pixels within lean muscle tissue range). Statistical analysis was performed using SPSS® v. 15. Results The baseline characteristics of the study participants are shown in Table 1. There was no significant difference in total CSA in longus colli, sternocleidomastoid and multifidus muscles between involved and uninvolved groups. Data analysis showed significant difference between the functional CSA of the lognus colli muscle the involved/uninvolved sides (Table 2). Also, there is significant difference in the ratio of longus colli musle (functional longus colli muscle CSA/total longus colli muscle CSA) between the involved and uninvolved sides ( P Conclusion This is the study to show via MRI assessment that patients with cervical radiculopathy have smaller ipsilateral functional CSA of the longus colli muscle LCM in comparison with uninvolved side. Consideration of these muscles in MRI could be helpful in the diagnosis and prognosis of cervical radiculopathy.