Biomechanical analysis of posterior screw fixations and allograft spacer in anterior cervical discectomy fusion: a finite element study

Anterior cervical discectomy fusion has a complication in which failure and subsidence of the allograft spacer occurs. In this study, the failure and subsidence risk stresses on allograft spacer were quantitatively analyzed using 6 different post-op models of ACDF with allograft spacer coupled with pedicle screw and/or lateral mass screw. Based on the comparative analysis of the results of the load sharing and subsidence risk, the pedicle screw was determined to provide better stability for the allograft spacer.