Novel risk factors for cervical facet joint degeneration in the subaxial cervical spine: correlation with cervical sagittal alignment and bone mineral density

Objectives The impact of cervical sagittal alignment on cervical facet joint degeneration (CFD) and risk factors for CFD in patients with Degenerative cervical myelopathy (DCM) were investigated in the current study. Methods A total of 250 surgical patients with DCM were recruited. Clinical data and radiographical characteristics including CFD, cervical sagittal balance parameters, Hounsfield unit (Hu) value, disc degeneration (DD), modic change were collected. The detailed correlation between these characteristics and CFD was analyzed. Characteristics including CFD were compared among various cervical alignment types and different CFD groups. Finally, risk factors for CFD were revealed via logistic regression. Results CFD was prevalent in DCM patients. Age, cervical sagittal vertical axis (cSVA), range of motion (ROM), T1 slope (T1S), thoracic inlet angle (TIA), DD, Hu value, and modic change were correlated with CFD segmentally and globally (p<0.05). Lordosis&sigmoid had significantly higher CFD prevalence (p<0.05). Further, the threshold of average CFD for the severe CFD group was determined to be 1.625 (AUC,0.958). Additionally, 167 patients with average CFD (<1.625) and 83 patients with FD≥1.625 were classified into the mild CFD group and severe CFD group respectively. Finally, multivariate analysis was performed and age, cSVA, Hu value, modic change and DD were determined to be the independent risk factors for CFD. Conclusion The load distribution tends to shift to a more shear-like pattern in sigmoid&kyphosis types or individuals with a higher cSVA, thereby promoting the CFD. Aging, cervical malalignment, low bone mineral density, disc degeneration, and modic change were revealed to have high risks for CFD.