Abstract: BACKGROUND: In clinical practice, to solve the problems of cervical spine revision/osteoporosis/long-segment fixation, anterior and posterior internal fixation is generally chosen to obtain satisfactory postoperative stability, which will inevitably aggravate the surgical trauma of the patients and increase probability of postoperative complications and hospitalization costs. The anterior cervical reverse pedicle internal fixation can obtain the stability of the anterior and posterior combined internal fixation through a single anterior operation, but there is no clinically applicable anterior cervical pedicle fixation system.
OBJECTIVE: 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. 
METHODS: The three-dimensional numerical value of the new nail plate system was obtained from the anatomical data of cervical spine specimens, and the system was produced by three-dimensional printing technology. Fresh adult cadaver cervical spine specimens were used to measure biomechanical stability in intact state (group A: complete group), and then to make a C5-7 instability model, followed by traditional cervical anterior nail plate system fixation (group B), anterior cervical spine displacement, strength, stiffness, torsion torque, under the fixed state of four screws fixed by the pedicle screw system (group C) and six screws (group D) of the anterior cervical pedicle screw system (group D) test.  
RESULTS AND CONCLUSION: (1) In terms of load-displacement relationship: the average displacement difference between group D and group C after the test was 25%, group D and group B were 30%, and group C and B were 18%, and the differences were statistically significant (P < 0.05). (2) In terms of the axial stiffness of the cervical spine: group D was 20% higher than group C and 40% higher than group B; group C was 20% higher than group B when fixed; group D and C were both better than group A; the differences were statistically significant (P < 0.05). (3) In terms of torsion mechanical properties of the cervical spine: the group D was higher than group C by 21%, higher than group B by 40%; group C was higher than group B by 30%; the difference was statistically significant (P < 0.05). (4) 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 group was better than the traditional group. The six-screw fixation group (group D) was better than the four-screw fixation group (group C). It is concluded that the new anterior cervical pedicle screw fixation system conforms to Chinese anatomy and has better mechanical stability than traditional fixation methods. It is a new reliable anterior cervical pedicle internal fixation system for clinical practice.

Key words: anterior cervical spine, pedicle, screw, internal fixation, biomechanics