Biomimetic Design of Fatigue-Testing Fixture for Artificial Cervical Disc Prostheses

Abstract

To investigate the biomechanical performances of artificial cervical disc (ACD) prostheses, many studies have been conducted, either with cervical sections of cadavers under physiological loads or with block-like testing fixtures obeying the ASTM F2346 standard. Unfortunately, both methods are almost impossible to utilize for accurate results of lifetime anti-fatigue experiments for at least 10 million cycles due to the difficulties in cadaver preservation and great deviations of natural cervical bodies, respectively. Based on normal human cervical structural features, a novel specimen fixture was designed for testing the fatigue behavior of ACD prostheses under flexion, extension, and lateral bending conditions, with aspects of both structural and functional bionics. The equivalence between the biomimetic fatigue-testing fixture and the natural cervical sections was investigated by numerical simulations and mechanical experiments under various conditions. This study shows that this biomimetic fatigue-testing fixture could represent the biomechanical characteristics of the normal human cervical vertebrae conveniently and with acceptable accuracy.

Advances in Stability of Metallic Implants

“…It is well known that the mechanical properties of medical implants have a significant impact on the in vivo performances after implantation, and biomimetic simulation and finite element analysis are effective methods for investigating the mechanical properties and in vivo stability of implants. Considering the structural features of natural human cervical, Cheng et al [2] designed a new fixture for measuring the fatigue properties of artificial cervical disc (ACD) prostheses under different mechanical conditions, including flexion, extension, and lateral bending. The numerical simulations and mechanical experiments were carried out to characterize the equivalence between the designed fixture and the natural cervical sections, and the results indicated that this novel biomimetic fixture could reflect the biomechanical characters of the natural human cervical vertebrae with acceptable accuracy.…”