Cervical spondylotic myelopathy (CSM) is the most severe type of cervical spondylosis and the most common cause of spinal cord dysfunction among adults over 55 years old [
1‐
4]. The clinical syndrome of CSM occurs when the stenosis impinges on the spinal cord, and the severity of CSM is generally thought to be related to the amount of mechanical compression of the various spinal cord tracts [
5]. The symptom of CSM ranges from mild impact on the daily life to paralysis. Decompression surgery is the most appropriate treatment after the diagnosis of CSM, which includes anterior, posterior and anterior-posterior approaches [
6,
7]. The diagnosis of CSM is based on clinical symptoms, physical and radiological examination including x-ray, computed-tomography (CT) and magnetic resonance image (MRI) [
5]. Compare to x-ray and CT scan, MRI can directly demonstrate the disc, spinal cord and the abnormal signal in spinal cord, which is the standard examination for CSM currently [
8‐
10]. Typically, static MRI can only show the neutral and static condition of the spinal cord, which is not adequate for the description of CSM because the cervical motion also plays an important role in the development of CSM [
1,
8‐
13]. Dynamic MRI (dMRI) is firstly described in 1980s, which is a modification of static MRI [
14]. Dynamic MRI could show the flexional and extensional position of cervical spine, which is more similar with the natural condition of cervical spine. Some changes of spinal cord would be missed in the static MRI and can be demonstrable in dMRI [
13]. Extension MRI helps to identify significant cervical canal stenosis that is partially or completely absent on neutral and flexion MRI. Flexion MRI permits better visualization of hyperintense intramedullary lesions (HILs) on T2-weighted sequence [
15]. For patients with cervical canal stenosis (CCS), neck extension may increase the severity of CCS due to the changes of nucleus pulposus, annulus and ligamentum flavum hypertrophy. Cervical flexion shows a relative decrease in total CCS, but the increased stenosis at the most stenotic level is more important [
15,
16].
Decompressive and reconstructive surgical techniques for the treatment of CSM may be divided into anterior, posterior, and combined surgical approaches. A systematic review comparing these approaches found similar outcomes that suggest the location of the pathoanatomy may guide the surgical decision making. The choice of which approach and surgical segment to use depends on the desired region of decompression and stabilization [
5,
17]. However, how to choose appropriate surgical approach and decompression segments is still controversial [
18]. Traditionally, the surgical plan for CSM patients are mainly based on the symptoms and radiographic results [
10,
19]. There is growing concerns about the significant value of dMRI for the assessment of CSM. Previous study suggest that preoperative extension MRI can be of great value to determine decompression levels for CSM more accurately [
8,
10,
11,
15,
19]. The priorities of dMRI compared to static MRI may modify the surgical decision making and potentially improve the surgical outcome for CSM patients. In this study, we aim to conduct a randomized clinical trial that will evaluate the clinical effectiveness of dMRI in the treatment of CSM compared to static MRI, which is the standard examination currently for CSM patients. Feasibility and validation research will be carried out in our trial to explore the indication and effectiveness of dMRI in the treatment of CSM patients, especially the surgical decision making.