Improvement of sagittal parameters in patients with cervical spondylotic myelopathy is associated with outcome after anterior cervical discectomy and fusion

Abstract

Purpose: After ACDF, cervical lordosis loss, high C2-7 SVA and postoperative T1S will worsen the surgical prognosis. Therefore, this study evaluated the changes of cervical parameters after surgery and correlation with surgical prognosis. Methods: This study enrolled 212 cervical compressive myelopathy patients who underwent ACDF. We collect gender, age, BMI, NDI scores and cervical parameters. And then, we compare the changes of parameters after surgery, and explore the correlation between parameters and NDI score. Results: C2-7 Cobb Angle, SVA, T1S and TS-CL were all improved after surgery, but T1S at the last follow-up was larger than that before the surgery. T1S is positively correlated with TIA (p=0.018, r=0.081), CL (p<0.01, r=0.150) and SVA (p<0.01, r=0.131), but negatively correlated with SCA (p<0.01, r=-0.166). We also found that TIA was highly correlated with the sum of T1S+NT (p<0.01, r=0.459). Preoperative NDI was negatively correlated with preoperative c2-7 Cobb Angle (r=-0.147, p=0.033), positively correlated with SVA (r=0.157, p=0.022). The last follow-up NDI score was negatively correlated with C2-7 Cobb Angle (r=-0.222 p=0.001), positively correlated with SVA (r=0.498, p<0.001) and TS-CL (r=0.165, p=0.016). The risk factors with poor follow-up NDI score (the last follow-up NDI score greater than 30%) were SVA (B=0.337, P=<0.001), CL (B=-0.147, P=0.029) and gender (B=2.153, P=0.017). Conclusions: After ACDF, most postoperative cervical parameters have improved, but T1S deteriorated over time. There was a close correlation between cervical sagittal parameters. Preoperative NDI score was correlated with c2-7 Cobb Angle and SVA. Follow-up NDI score was correlated with CL, TS-CL and SVA. High SVA, loss of cervical lordosis and male patient were risk factors for the deterioration of postoperative NDI score.