Is it possible to evaluate upper and lower cervical interdependency on supine magnetic resonance imaging?

Abstract

There is a significant correlation between the upper and lower cervical alignments associated with a compensatory mechanism to maintain horizontal gaze. Evaluating this correlation before cervical fusion operations is essential, particularly in the upper cervical region, to prevent the occurrence of postoperative malalignment. This study was designed to investigate whether evaluating the interdependency between the upper and lower cervical alignments on neutral supine magnetic resonance imaging (MRI) or supine MRI with neck extension is possible. This study included 36 male and 30 female volunteers without symptoms aged between 16 and 60 years. Cervical radiographic images and supine cervical spinal MRI scans were obtained twice on the neutral supine position and on the supine position with pillows placed at 5 cm high under the shoulder. Cervical lordosis (CL) (C2–7 Cobb angle), C0–2 Cobb angle, C2–7 sagittal vertical axis (C2–7SVA), T1 slope (T1S), and T1 slope minus CL (T1S-CL (C2S)) were measured from the imaging sets from each patient, including X-ray images and two MRI scans, and the main values were obtained. The mean values of the measurements from the radiographic images were compared with those obtained from MRI scans using Student’s t-test. The agreement between the parameters (C0–2 Cobb angle, CL Cobb angle, and T1S-CL) obtained from the radiographic images and MRI scans was evaluated using Pearson correlation analysis. Pearson correlation analysis revealed significant correlations between the C0–2 and C2–7 Cobb angles in standing X-ray and neutral MRI values (r = −0.425 and -0.397, respectively). In plain radiography and MR studies, the T1 slope was correlated with the C2–7 angle (r = 0.4824, 0.734, and 0.702, respectively). The C2 slope values were also significantly correlated with the C0–2 Cobb angle in standing X-ray and neutral MRI images (r = 0.5595 and 0.5719, respectively). There were significant correlations between the C2 slope and C2–7 Cobb angles in all modalities (r = −0.5645, −0.7917, and −0.8526). Negative correlations between the upper and lower cervical alignments are also present in supine MRI studies, consequently in the supine position, with statistical significance. The C2 slope is an important cervical spine parameter that is significantly correlated with both the C0–2 and CL Cobb angles. The C2 slope can be used to evaluate the interdependency of the upper and lower cervical alignments.