Comparison of the Effects of Posterior Cervical Fixation or Posterior Cervical Fixation Extending to the Upper Thoracic Region on Cervical Sagittal Alignment

ObjectiveFor degenerative diseases accompanied by cervical malalignment, the starting and ending points of fixation for better cervical sagittal alignment and clinical results are not as clear as the thoracolumbar region. In this study we aimed to compare the effects of posterior subaxial cervical fixation (PSCF), posterior cervical fixation extending to the upper thoracic region and posterior upper cervical fixation extending to the upper thoracic region on cervical sagittal alignment.MethodsSixty-three patients who underwent posterior cervical and cervical-up thoracic fixation were retrospectively analyzed in a comparative study. The procedures that we performed from May 2019 to March 2022 on these 63 patients were: (1) C3-C6 group-posterior subaxial cervical fixation; (2) Subaxial-T2 group-posterior subaxial cervicothoracic fixation (PSCTF); (3) C2-T2 upper thoracic posterior fixation group. The C3-C6 group had 27 patients, Subaxial-T2 group had 24, and C2-T2 group had 12. We determined the minimum follow-up period as 12 months. C0-2, C2-7 lordosis angle, sagittal vertical axis (SVA), C2 slope, C7 slope, T1 slope, cervical slope, neck slope, and thoracic inlet angle (TIA) measurements were made in three patient groups. Comparatively, cervical sagittal alignment was evaluated.ResultIn the C2-T2 group, a significant increase in C2-C7 lordosis, decrease in C2 slope, and increase in TS-CL were observed. Significant C2-C7 lordosis decrease, C2 slope increase, and TS-CL decrease were observed in the C3-C6 group. A significant increase in C2-C7 lordosis and a decrease in C2 slope were observed in the subaxial-T2 group. No significant change was observed in the TS-CL angle.ConclusionIn cervical degenerative disorders accompanied by cervical malalignment, we recommend the C2-T2 fixation method, which provides the desired C2-C7 lordosis, SVA within the normal range, and the best Neck Disability Index results. This figure illustrates the changes in various spinal angles and the statistical significance of these changes across C2-T2, C3-C6, and Subaxial-T2 surgical groups. The left panel shows the mean changes in different spinal angles (units) for each group. The right panel displays the p-values of these changes, indicating their statistical significance (C2-T2: Blue; C3-C6: Orange; Subaxial-T2: Green). image