Correlation between cervical spine sagittal alignment and clinical outcome after anterior cervical discectomy and fusion.

Studies have shown that maintenance of lordosis improves outcomes after anterior cervical discectomy and fusion (ACDF). The relationship between maintenance or restoration of lordosis after ACDF and health-related quality of life (HRQOL) measures has not been evaluated. Preoperative and 2-year postoperative cervical lordosis (C2-C7) and segmental lordosis were measured from upright lateral cervical spine radiographs in patients who had ACDF. Data on the Neck Disability Index (NDI), Short- Form-36 Physical Composite Summary Score, arm, and neck pain scores were also collected. Paired t-tests were used to compare preoperative and 2-year postoperative radiographic measures and HRQOL measures. Receiver operating characteristic curves were constructed to identify sagittal parameters that predict achievement of a Minimum Clinically Important Difference (MCID) in outcome measures. One hundred one patients (75 female; mean age, 52 years) were included. There was improvement in all HRQOL measures from preoperative to 2 years postoperative. There was no significant difference in preoperative and 2-year postoperative sagittal alignment. Receiver operating characteristic curve analysis showed that a postoperative cervical lordosis of at least 6° predicted achievement of MCID for NDI (8 point change in NDI). This suggests that maintenance or restoration of overall cervical lordosis is important in achieving a successful result after ACDF.