[Biomechanical evaluation of anterior cervical spine stabilization with step-cut grafting and absorbable screw fixation].
OBJECTIVE
To determine the initial stability of a novel construct in cadaveric cervical spine in comparison with a conventional method.


METHODS
Twelve specimens of fresh human cadaveric cervical spines (C(3)-C(7)) were randomly divided into the test group and control group. In the former group, one-level corpectomy of C(5) and three cortical iliac step-cut grafting with absorbable screw fixation was performed, and one-level corpectomy of C(5) and three cortical iliac strut grafting with anterior plate fixation in the control group. Flexibility test and graft push of strength test were carried out before and after grafting and fixation to determine the range of motion (ROM), neutral zone (NZ) and graft push out strength (POS).


RESULTS
The cervical spines of the two groups all had increased initial stability in all 6 rotational degrees of freedom with also enhanced graft POS after fixation. Compared with the control group, the test group had higher stability in extension and comparable stability in flexion and axial rotation, but lower stability in lateral bending. The graft POS after fixation in the test group, however, was lowered in comparison with the control group.


CONCLUSIONS
Step-cut grafting and absorbable screw fixation provides sufficient stability potential for the cervical spine in vitro and allows optimum biomechanical and biological environments to enhance graft fusion and reduce complications.
Zhang
Jian
J
Department of Orthopedics, Second Hospital of Xi'an Jiaotong University, Xi'an 710004, China. zhangjian-937@163.com
He
Xi-jing
XJ
Li
Hao-peng
HP
Wang
Dong
D
Zhao
Wei-dong
WD
D020341:Absorbable Implants; D001696:Biomechanical Phenomena; D001863:Bone Screws; D016025:Bone Transplantation / Q000379:methods*; D002102:Cadaver; D002574:Cervical Vertebrae / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology / Q000517:prevention & control; D019637:Orthopedic Procedures / Q000295:instrumentation / Q000379:methods; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*