A new anterior cervical pedicle screw fixation system was developed based on the relevant anatomical structure of the cervical spine, and its biomechanical properties were evaluated on fresh cadaver cervical spine specimens to provide a basis for preliminary clinical application.
Three-dimensional parameters of the new nail plate system were obtained from the anatomical data of cervical spine specimens, and the system was produced by 3D printing technology. Fresh adult cadaver cervical spine specimens were used to measure biomechanical stability in the intact state (group A: complete group) and to establish a C5-7 instability model in which fixation with the traditional cervical anterior nail plate system was performed (group B). Anterior cervical spine displacement, strength, stiffness, torsion torque, etc. were measured under the fixed state when 4 screws were used for fixation with the pedicle screw system (group C) and 6 screws were used for the anterior cervical pedicle screw system (group D).
In terms of the load-displacement relationship, the results showed that the average displacement difference between group D and group C after the test was 25%, that between group D and group B was 30%, that between groups C and B was 18%, and the differences were statistically significant (P <0.05). In terms of the axial stiffness of the cervical spine, that of group D was 20% higher than that of group C and 40% higher than that of group B, that of group C was 20% higher than that of group B when fixed, and those of group D and C were both better than that of group A, the blank control group; all the differences were statistically significant (P<0.05). In terms of torsion mechanical properties of the cervical spine, the experimental results showed that that of group D was higher than that of group C by 21% and higher than that of group B by 40%, that of group C was higher than that of group B by 30%, and the differences were statistically significant (P<0.05). The biomechanical tests showed that in terms of load-displacement, axial stiffness and torsional mechanical properties, the anterior cervical pedicle locking and guiding internal fixation system was slightly better than the complete method. The 6 nail fixation method was better than the 4 nail fixation method.
The new anterior cervical pedicle screw fixation system conforms to the anatomy of Chinese individuals and has better mechanical stability than do traditional fixation methods. It is a new, reliable anterior cervical pedicle internal fixation system for clinical practice.List of Abbreviations: ACPS: anterior cervical pedicle screw.