Role of the biomechanical property of the endplate in anterior cervical fusion.

OBJECTIVE

To study the distribution of the biomechanical properties in the cervical vertebrae with or without the endplate, so as to evaluate the importance of the endplate in cervical anterior fusion.

METHODS

Indentation tests were performed at 20 standardized testing points chosen on each surface of the endplate with the impact adjusted perpendicular to the endplate surface using a hemispherical indenter 2 mm in diameter. The failure load and rigidity at each test site were determined from the load-displacement curves. Independent sample t test and factorial analyses were used to analyze the results.

RESULTS

On either superior or inferior endplate surface, both the failure load and rigidity differed significantly between the endplate-intact and endplate-removed groups (P < 0.001). The posterior region of the superior endplate and the lateral regions of the inferior endplate were stronger and more rigid than any other region across the endplate surface in the endplate-intact group, while for enplate-removed group, the posterior region of the superior endplate and the posterolateral regions of the inferior endplate were the stronger and more rigid.

CONCLUSION

The endplate plays an important role in deciding the success of anterior cervical fusion, and due attention should be paid to the endplate in the intervertebral implant device designing and the surgical approach modification.