Biomechanical comparison between artificial atlanto-odontoid joint replacament and Magerl transarticular screw fixation / 中国矫形外科杂志

ABSTRACT

[Objective]To determine the initial stability and function of a new artificial joint in a cadaveric cervical spine model by comparing it with a conventional method. [Methods]Twelve fresh human cadaveric cervical spines(C0~3) were randomly divided into 2 groups group 1,resection of the odontoid with artificial atlanto-odontoid joint(AAOJ),and group 2,resection of the odontoid with Magerl atlas and axis by transarticular screw fixation(Magerl).For each specimen,the intact and resection of the odontoid underwent a flexibility test firstly,followed by the instrumented construct.Rotational angles of the C0~3 segment were measured to study the immediate stability and function of resection of the odontoid and AAOJ,compared with the intact and resection of the odontoid and Magerl.[Results]Compared to the intact state,resection of the odontoid and AAOJ resulted in a significant decrease in the range of motion(ROM) and neutral zone(NZ) during flexion,extension,and lateral bending(P0.05).Compared to the intact state,resection of the odontoid and Magerl resulted in a significant decrease in the range of motion(ROM) and neutral zone(NZ) during all 6 degrees of freedom(P0.05).[Conclusion]A new type of artificial atlanto-odontoid joint has been designed for correcting atlantoaxial instability resulted from C1、2 anterior decompression procedures.It can restore,to a great extent,the C1、2 axial rotation that is lost during current stabilization procedures.