Correlation between C7–T1 Intervertebral Foramen Area and Sagittal Parameters in Patients with Cervical Spondylotic Myelopathy

OBJECTIVE: Cervical spondylotic myelopathy (CSM) is an incomplete spinal cord injury characterized with pain and stiffness in the neck and motor and sensory dysfunction. This study aims to determine whether C7–T1 intervertebral foramen area could be used as a parameter to evaluate the sagittal curvature of cervical spine. METHODS: Patients with clinical manifestations of spinal cord compression were hospitalized in our hospital from September 2018 to August 2019. All patients were diagnosed with CSM by nuclear magnetic imaging and other imaging methods. C2–C7 Cobb angle and T1 slop (T1S) were measured on the sagittal, T2‐weighted magnetic resonance image of cervical spine, and C7–T1 intervertebral foramen area were measured using oblique cervical spine X‐rays. Patients were divided into two groups according to the value of C2–C7 Cobb angle, including lordosis group (C2–C7 Cobb angle >10°, n = 45) and straight group (C2–7 Cobb angle ≤10°, n = 55). The reliability of the data was evaluated by intraclass correlation coefficient (ICC), and the correlation of the imaging parameters was analyzed by Pearson correlation. RESULTS: A total of 100 patients diagnosed with CSM hospitalized in our department were included. The ICC of the cervical parameters was 0.73. C7–T1 intervertebral foramen area was 40.69 ± 11.44 and 39.95 ± 10.94 mm(2) in lordosis and straight group, respectively. The results showed that C7–T1 intervertebral foramen area was positively correlated with both C2–C7 Cobb angle (r = 0.23, p = 0.02) and T1S (r = 0.21, p = 0.03). In lordosis group, there was a positive correlation between C7 and T1 intervertebral foramen area and C2–C7 Cobb angle (r = 0.69, p < 0.01) and T1S (r = 0.34, p = 0.02). However, in straight group, C7–T1 intervertebral foramen area was not correlated with either C2–C7 Cobb angle or T1S. CONCLUSION: C7–T1 intervertebral foramen area measured by oblique X‐ray could be an effective method to evaluate the sagittal balance of cervical vertebrae for CSM patients with cervical lordosis.