Is posterior cervical imbalance after anterior cervical discectomy with fusion a determinant in the development of adjacent cervical degeneration? A retrospective study with an average of 8 years of follow-up.

Aims: The primary objective of this study is to evaluate the hypotheses that postoperative sagittal imbalance influences the development of adjacent segment degeneration (ASDeg) in patients who have undergone an anterior cervical discectomy with fusion (ACDF).

Settings and design: This was a retrospective cohort study.

Subjects and methods: We analyzed 63 patients with ACDF with a minimum of 2 years of follow-up. In the imaging evaluation, sagittal balance parameters were included, as well as radiographic parameters that target the development of ASDeg. In addition, discrimination was made between arthrodesis techniques.

Statistical analysis used: Categorical variables were compared using the Chi-square test and Fisher's exact test. Continuous variables were compared using t-test when the data were normally distributed and Wilcoxon tests when the distribution was not normal.

Results: Patients with postoperative imbalance presented with radiographic ASDeg at a rate of 26% (n = 5) versus 22% (n = 9) in patients with postoperative balance, this difference was not significant (P = 0.7). In those who underwent surgery with plate, we found that 23% (n = 4) developed ASDeg versus 22% (n = 1) of patients with anterior cervical arthrodesis with cage-plate and 27% (n = 10) of patients who underwent interbody device surgery, with this difference being nonsignificant (P = 0.7).

Conclusion: We concluded that neither postoperative imbalance nor the type of arthrodesis in patients undergoing ACDF for degenerative pathology showed a positive correlation with the development of radiographic cervical ASDeg at an average follow-up of 8 years.