Biomechanical effects of a novel anatomic fusion cage for anterior cervical corpectomy: a finite element study

Anterior cervical corpectomy and fusion (ACCF) is a crucial surgical procedure for addressing cervical degenerative diseases. However, traditional titanium mesh cages (TTMC) are susceptible to complications, such as cage subsidence and internal fixation failure. In this study, we developed a novel anatomic titanium mesh cage (NATMC) and assessed its biomechanical properties through finite element analysis. A conventional three-dimensional finite element model comprising cervical vertebrae C2–C7 was established using computed tomography (CT) data. Subsequently, two surgical models (TTMC and NATMC) were generated based on the normal model. Uniform load conditions were applied to these distinct surgical models to simulate flexion, extension, lateral bending, and axial rotation of the cervical spine. The range of motion (ROM), stress peaks at the titanium mesh-endplate interface, screw–bone interface, and the adjacent intervertebral disc were recorded and compared between the two groups. In comparison to the intact model, the surgical segmental range of motion (ROM) for C4-6 was reduced by 96.89% in NATMC and 96.91% in TTMC. The stress peaks at the C4 inferior endplate and C6 superior endplate were higher in TTMC, measuring between 1.61 and 9.96 MPa and 1.46–14.29 MPa, respectively, followed by NATMC with values of 0.93–7.75 MPa and 1.08–11.69 MPa. Stress peaks on NATMC were lower (68.47–309.90 MPa) compared to TTMC (86.80–368.30 MPa). Regarding stress peaks at the screw-bone interface, NATMC exhibited lower values (11.91–42.49 MPa) compared to TTMC (35.49–153.00 MPa). Finally, comparing stress peaks in adjacent discs (C3/4 and C6/7), NATMC and TTMC showed similar results, ranging between 1.56 and 5.47 MPa in C3/4 and 1.56–2.91 MPa in C6/7, respectively. The novel anatomic titanium mesh cage demonstrated effective reduction in vertebral subsidence and minimized pressure on the internal fixation interface following anterior cervical corpectomy and fusion (ACCF). It demonstrated superior stability and safety compared to traditional titanium mesh cage.