The objective of this clinical investigation is to compare patients treated with Anterior Cervical Discectomy and Fusion (ACDF) using the Hedrocel Cervical Fusion Device, with a concurrent, randomized, control group receiving autologous iliac crest bone graft or allograft and test the hypothesis that ACDF with Hedrocel is non-inferior to ACDF with allograft or autologous bone graft.