Table 1 Summary of results for three forward stepwise regression analyses. Each regression analysis retained one significant predictor variable (the fusion score) to predict the improvement of the VAS pain score at the same corresponding follow-up timepoint. The r² indicates the amount of variance of the outcome variable predicted by the model (e.g. model 1 explains 8% of the data variance of the improvement of VAS from pre-op to 6 M). Note also that because each of these models retained only one predictor variable, the standardized coefficient (β) is equal to the correlation coefficient between the predictor variable and outcome variable

From: Empty polyetheretherketone (PEEK) cages in anterior cervical diskectomy and fusion (ACDF) show slow radiographic fusion that reduces clinical improvement: results from the prospective multicenter “PIERCE-PEEK” study