CORA ABSTRACT #VI - 1

A BIOMECHANICAL STUDY OF C1-C2 TRANSARTICULAR SCREW FIXATION

M. Sen

T. Steffen

M. Aebi

Study Design: An experimental study of the biomechanical stability of the atlantoaxial joint using three methods of transarticular fixation.

Objectives: To determine how transarticular screw fixation using anterior screws compares to posterior screws with and without cerclage wires.

Background: The best results for fusion of the atlantoaxial joint have been obtained with techniques using posteriorly placed transarticular screws. The anterior surgical approach to the cervical spine has several advantages over the posterior approach. Some centers have attempted fixation of the atlantoaxial joint using anterior transarticular screws, but the stability of this construct has not been evaluated.

Method: Ten human cadaveric specimens were used. The C1-C2 motion segment was isolated and instrumented using either anterior transarticular screws, or posterior transarticular screws with and without cerclage wires. The specimens were then tested in translation, flexion-extension, rotation, and lateral bending and measurements of displacement were made.

Results: Posterior transarticular screws with cerclage wires were stiffer in flexion-extension only. No significant difference in stiffness between the three groups was found under translation, lateral bending, or rotation.

Conclusion: No clinically relevant difference in stability was shown between the three constructs. Anterior transarticular screw fixation therefore provides a suitable alternative to posterior screw fixation in atlantoaxial fusion.