Biomechanical Comparison of Optimal Shapes for the Cervical Intervertebral Fusion Cage for C5–C6 Cervical Fusion Using the Anterior Cervical Plate and Cage (ACPC) Fixation System: A Finite Element Analysis

Abstract

BackgroundThe fifth and sixth cervical vertebrae (C5–C6) represent the high-risk segment requiring surgical correction in cervical spondylosis. Anterior cervical discectomy and fusion (ACDF) of C5–C6 includes an intervertebral fusion cage to maintain foraminal height and is combined with anterior plate fixation. The shape of the intervertebral cage can affect the postoperative outcome, including the rates of fusion, subsidence, and neck pain. This study aimed to use finite element (FE) parametric analysis to compare biomechanical properties of changes in intervertebral cage shape for C5–C6 cervical fusion using the anterior cervical plate and cage (ACPC) fixation system.Material/MethodsFive shapes were designed for cervical intervertebral cages, square, oval, kidney-shaped, clover-shaped, and 12-leaf-shaped. The performance was evaluated following implantation into the validated normal C5–C6 FE model using simulation with five physiological conditions. The indicators included the maximum von Mises stress of the endplates, the fusion cages, and the cervical vertebrae. The postoperative subsidence-resistance properties were determined, including the interior stress responses of the intervertebral cages and the surrounding tissues. The fusion-promoting properties were evaluated by the interior stress responses of the bone grafts.ResultsThe optimal shape of the cervical intervertebral cage was the 12-leaf-shape for postoperative subsidence resistance. The kidney shape for the cervical intervertebral cage was optimal for postoperative fusion.ConclusionsFE analysis identified the optimal cervical intervertebral cage design for ACPC fixation of C5–C6. This method may be useful for future developments in the design of spinal implants.

Biomechanical Comparison of Posterior Fixation Combinations with an Allograft Spacer between the Lateral Mass and Pedicle Screws

“…Therefore, this study could lack sufficient evidence to support the validation of this FEM. Nevertheless, in many biomechanical studies, ROM was utilized to validate and verify models, as well as to predict stress and forces reflective of real-world settings [31][32][33][34][35][36][37].…”

The biomechanical effects of S-type dynamic cage using Ti and PEEK for ACDF surgery on cervical spine varying loads

“…17 In order to provide bone fusion between the adjacent vertebra a square window of 5 mm is provided in the center of the cage. 20 The cage model was virtually inserted in to the C4-C5 level after the removal of the intervertebral disc, and the anterior longitudinal ligament.…”

“…The coefficient of friction between the vertebrae and cage is 0.07. 20 The ligaments used in this study are anterior longitudinal ligament (ALL) the capsular ligament (CL), the posterior longitudinal ligament (PLL), the ligamentum flavum (LF), and the interspinous ligament (ISL). The ligaments were modeled using tension only link elements.…”

Structure Design and Optimization of the C5–C6 Cervical Intervertebral Fusion Cage Using the Anterior Cervical Plate and Cage Fixation System

“…This study was follow-up research of a previous study of the influence of shape changes of cervical cages on the biomechanical properties of ACPC [ 26 ]. The previous C5–C6 FE model with fixed plate and screw was used.…”