Relationship Between Cervical Sagittal Alignment and Patient Outcomes After Anterior Cervical Fusion Surgery Involving 3 or More Levels.

Abstract

T1 slope minus C2-7 lordosis (TS-CL) and cervical sagittal alignment reportedly affect health-related quality of life (HRQOL) scores after multilevel posterior cervical fusion surgery. There are no reports of a relationship between cervical alignment and patient outcomes after anterior cervical discectomy and fusion (ACDF) involving 3 or more levels. This study aimed to investigate the relationship between cervical sagittal alignment and patient-reported HRQOL after ACDF involving 3 or more levels. Thirty-three patients underwent ACDF involving 3 or more levels for cervical stenosis, cervical degenerative disorder, or ossification of the posterior longitudinal ligament (February 2006-April 2015). Mean follow-up duration was 57.6 ± 33.2 months. Radiographic measurements included C0-2 lordosis, C2-7 lordosis, C2-7 sagittal vertical axis (SVA), T1 slope, and T1 slope minus cervical lordosis (TS-CL). Clinical outcomes were evaluated by Neck Disability Index (NDI) and visual analog scale (VAS) scores. There were significant correlations between C2-7 lordosis and T1 slope (r= 0.581, P= 0.004), and between C2-7 lordosis and TS-CL (r=-0.579, P= 0.004). C2-7 lordosis, C2-7 SVA, and TS-CL had no significant correlations with NDI or VAS score after surgery. C2-7 SVA was not significantly different before and after surgery. Postoperative TS-CL (P= 0.01) and changes in T1 slope (P= 0.028) and TS-CL (P= 0.01) were significantly correlated with changes in NDI. ACDF surgery involving 3 or more levels under neutral supine position did not significantly change the postoperative cervical alignment, and thus may not significantly affect cervical alignment or HRQOL.