Biomechanical Study On The Immediate Stability Of One-level Cervical Spine After ACDF With Two Kinds Of Internal Fixation And Fusion System

Objective: To analysis the immediate stability of two different kinds of internal fixation to reconstruct the immediate stability of the goat’s cervical vertebral single-level anterior cervical discectomy and fusion,and compared with titanium combine with interbody cage.In order to explore the fixed properties of the two internal fixed devices,and to provide a biomechanical basis for the clinically reasonable and effective selection of internal fixers.Methods:24 adult goat cervical3/4 vertebral specimens were randomly divided into 4 groups: Group A is a non-operated group,Group B is a Zero-p group,Group C is a regular titanium plate and interbody cage group,group D is a Skate-plate cervical fusion device group.With C3/4 single-level interbody space as the research object,Non-destructive biomechanical test of flexion,extension,lateral bending and rotation with 6 degree of freedomrobotic manipulator was carried out,and the range of motion and neutral zone were recorded.After one cycle of loading test and record,B,C and D groups were conducted with 0.25 HZ,3000 times of rotation loading,and the ROM and NZ under six working conditions were measured again.Results:1.Compared with the non-surgery group,the ROM and NZ of the Zero-p group,titanium plate combined with cage group and Skate-plate cervical fusion device group were significantly reduced under 6 working conditions,except the ROM and NZ of extension of Skate-plate cervical fixation group were not statistically different from those in non-surgery group(P>0.05),the other mechanical indicators were significantly different from those in the non-surgery group(P<0.05);2.There was no significant statistical difference in ROM and NZ between the Zero-p group and titanium plate combine with cage group(P>0.05);3.There was no significant statistical difference inROM and NZ of rotation between the Skate-plate cervical fusion device group,titanium plate combine with cage group and Zero-p group(P>0.05);but the mechanical indications in the lateral bending,flexion and extension condition of Skate-plate cervical fusion device group is greater than those of the Zero-p group or titanium plate combine with cage group,and there was statistical difference(P<0.05);4.After 3000 times rotation,the ROM and NZ of each fixation group were slightly increased,but there was no screw or plate loosening,and there was no significant statistical difference compared with those before rotation(P>0.05);Conclusion:1.Zero-p provides cervical spine with biomechanical properties similar to the traditional titanium plate combined with interbody cage,especially with superior fixed effect severity in anti-rotation performance;2.Zero-p,ACPS,Skate-plate in the maximum physiological load,range of 3000 times to torsion will not cause the internal fixation loose;3.Skate-plate cervical fusion device can effectively reduce the ROM and NZ after single-level cervical ACDF,although the biomechanical property of Skate-plate is weaker than Zero-p and plate combine cage,but it also can provide biomechanical properties to meet the clinical needs,its design conforms to the anatomical and mechanical characteristics of the cervical spine,can better match the mechanical environment of the cervical spine.