Can C2-6 Cobb Angle Replace C2-7 Cobb Angle?: An Analysis of Cervical Kinetic Magnetic Resonance Images and X-rays

Study Design. Retrospective study of consecutive 113 cervical kinetic magnetic resonance images (kMRIs) and 57 radiographs. Objective. To elucidate the relationship between C2-6 or C2-7 Cobb angle and cervical sagittal alignment parameters using kMRI, and evaluate the visibility of C6 and C7 inferior endplates on cervical radiographs. Summary of Background Data. Several studies have used C2-6 Cobb angle instead of C2-7 Cobb angle as C7 inferior endplate is not always visible because of overlying shadows. However, the relationship between C2-6 or C2-7 Cobb angle and cervical sagittal alignment parameters remains unclear. Moreover, visibility of C6 inferior endplate remains unknown. Methods. C2-6 Cobb angle, C2-7 Cobb angle, occiput-C2 angle, Atlas-dens interval (ADI), narrowest oropharyngeal airway space (nPAS), cervical sagittal vertical axis (cSVA), cervical tilt, cranial tilt, neck tilt, thoracic inlet angle (TIA), and T1 slope were measured using kMRI, and analyzed for their relationship with C2-6 or C2-7 Cobb angle. Visibility rates of C6 or C7 inferior endplates were evaluated using cervical radiographs. Results. Linear regression analysis showed high association between C2-6 and C2-7 Cobb angle (R2ā€Š=ā€Š0.696, Pā€Š
Source: Spine - Category: Orthopaedics Tags: CERVICAL SPINE Source Type: research