Does Cervical Sagittal Balance Affect the Preoperative Neck Disability Index in Patients With Cervical Myelopathy?

Abstract

This was a retrospective study. This study aimed to ascertain the relationship between preoperative Neck Disability Index (NDI) scores and cervical sagittal alignment in patients with cervical spondylotic myelopathy (CSM). Cervical alignment may influence postoperative clinical outcomes. However, the effect of preoperative sagittal balance on the preoperative status in CSM patients remains uncertain. From 2010 to 2016, 90 patients who underwent cervical surgery for CSM were enrolled. The inclusion criteria for this study included preoperative standing cervical radiographs and a preoperative NDI score. The following radiographic parameters were measured: (1) C0-C2 lordosis, (2) C2-C7 lordosis, (3) C2-C7 sagittal vertical axis (SVA), (4) neck tilt, (5) thoracic inlet angle, (6) T1 slope, and (7) T1 slope minus cervical lordosis (T1S-CL). The Pearson product-moment correlation coefficients were calculated between all radiographic variables and the NDI scores, and multiple regression analysis was performed to determine the independent predictors of high preoperative NDI scores. Both C2-C7 SVA and T1S-CL were positively correlated with NDI scores (r=0.732, P<0.001 and r=0.333, P=0.001). Cervical lordosis was negatively correlated with NDI scores (r=-0.267, P=0.011). Significant correlations were found between C2-C7 SVA and the C0-C2 Cobb angle (r=0.244, P=0.020), C2-C7 SVA and the C2-C7 Cobb angle (r=-0.359, P=0.001), the C2-C7 Cobb angle and the C0-C2 Cobb angle (r=-0.457, P<0.001), and the C2-C7 Cobb angle and T1 slope (r=-0.385, P<0.001). The disability of the neck increased with increasing C2-C7 SVA and T1S-CL and decreasing cervical lordosis before surgical reconstruction. High C2-C7 SVA, low thoracic inlet angle, and high neck tilt values are independent predictors of high preoperative NDI scores.