Feng SW, et al. - This study involved a comparison between empty PEEK cages and PEEK cages packed with β-tricalcium phosphate, focusing on the clinical outcomes, radiographic results and fusion rate of ACDF. Using ACDF with PEEK cages and instrumentation afforded similar fusion rates and clinical outcomes regardless of whether the cage was filled with bone substitute. Data also revealed improved fusion rates over time and comparable fusion rates between both groups.