Cervical spine loading characteristics in a cadaveric C5 corpectomy model using a static and dynamic plate.

Abstract

Anterior plates are used to increase the initial stability of anterior cervical spine fusions; however, plating has been suggested to cause graft stress shielding, leading to reduced fusion rates. The objectives of this study were to quantify the effects of graft size and plating (static versus dynamic) and the role of the posterior elements on load transmission in anterior cervical fusion. A C5 corpectomy was performed on six human cervical spines (C3-C7). An instrumented height-adjustable graft and dynamic cervical plate were used to measure axial load transmission. Each specimen underwent axial compressive testing with dynamic and static plate configurations, optimal and undersized graft heights, and posterior elements intact and removed. Dynamic plating allowed significantly more load transmission by the graft, particularly in the undersized graft configuration. The posterior elements play a significant role in load transmission.