Biomechanical study of a novel self-locking plate system for anterior cervical fixation

BACKGROUND Anterior cervical plate had developed continuously, and this study aimed to assess the biomechanics of a novel self-locking plate system for anterior cervical fixation designed by ourselves. METHODS Twelve anterior cervical plates (i.e., six novel plates and six DePuy plates) were subjected to a pull-out test and a fatigue test. In addition, 12 C1-T1 cervical spine specimens underwent anterior cervical corpectomy and C5 fusion using six novel plates and six DePuy plates. Pre- and postoperative range of motion, load-displacement, axial stiffness, torque, and twisting stiffness were compared. RESULTS No differences in maximum pull-out force, relative displacement, or energy absorption were observed between the DePuy plates and the novel plates (P >0.05). The novel plate system could bear an average of 5.6 × 105 times of loading, while the DePuy plate could bear 5.4 × 105 times of loading. The fatigue strengths of the new plate system and the DePuy plate were 490.75 and 485.86 MPa, respectively. No differences in fatigue life or strength were observed between the two types of plates. Cervical spine stability increased significantly after internal fixation. No differences in range of motion, load-displacement, axial stiffness, torque, or twisting stiffness were observed between the novel self-locking plate and the DePuy plate (P >0.05). CONCLUSIONS Compared to the DePuy plate, the novel anterior cervical self-locking plate system described here has good strength and fastening ability, allowing it to provide sufficient biomechanical stability. Further clinical assessment of this system is needed.