Do Inflammatory Cytokines Affect Patient Outcomes After ACDF?

Study Design: Prospective cohort study. Objective: The aim was to determine the relationship between serum inflammatory mediators, preoperative cervical spine disease severity, and clinical outcomes after anterior cervical discectomy and fusion (ACDF). Summary of Background Data: Given the role of the inflammatory cascade in spinal degenerative disease, it has been hypothesized that inflammatory markers may serve as a predictor of patient outcomes after surgery. Materials and Methods: All patients over age 18 who underwent ACDF for cervical spondylosis with associated radiculopathy and/or myelopathy between 2015 and 2017 from a single institution were prospectively recruited. Preoperative serum inflammatory markers including interleukin (IL)-6, IL-8, tumor necrosis factor-alpha, high-mobility group box-1 (HMGB1), and white blood cells were measured and correlated to patient demographics, surgical characteristics, duration of symptoms, previous opioid use, and preoperative and 1-year postoperative patient-reported outcomes measures (PROMs) including the neck disability index (NDI), visual analog scale neck pain, visual analog scale arm pain, and Physical and Mental Component Scores of the Short Form-12 (PCS and MCS, respectively) using spearman's rho coefficient. Results: A total of 77 patients were enrolled with follow-up PROMs available for 62% (n=48) of patients at a minimum of 1-year after ACDF. The absolute concentrations of IL-6 and tumor necrosis factor-alpha were found to be weakly correlated with one another (rho=0.479). Preoperative symptoms lasting <1-year were weakly correlated with elevation in HMGB1 (rho=0.421). All other patient demographics exhibited negligible correlation with the preoperative inflammatory markers. Lower preoperative PCS (rho=0.355) and higher preoperative NDI (rho=0.336) were weakly correlated with elevated HMGB1. Lower MCS (rho=0.395) and higher NDI (rho=0.317) preoperatively were weakly correlated with elevated white blood cells. Postoperative improvement in MCS (rho=0.306) and MCS recovery ratio (rho=0.321) exhibited a weakly positive correlation with IL-6. Conclusion: Preoperative cytokine levels demonstrated minimal correlation with preoperative symptoms or clinical improvement, suggesting that profiling of patient cytokines has limited utility in predicting outcomes after ACDF.