Turkish Neurosurgery
Can C2-Pars Interarticularis Screw be an Alternative in Atlanto-Axial Stabilization? A Biomechanical Comparison of Established Techniques
Philipp Schleicher1, mehmet bulent Onal2, Frank Hemberger1, Matti Scholz1, Frank Kandziora1
1Berufsgenossenschaftliche Unfallklinik Frankfurt am Main, Zentrum für Wirbelsäulenchirurgie und Neurotraumatologie, Frankfurt,
2Acibadem University, Department of Neurosurgery, Istanbul,
DOI: 10.5137/1019-5149.JTN.23791-18.2

Aim:The atlanto-axial complex is usually stabilized by a posterior transarticular screw placement (Magerl) or thru a posterior internal fixator according to Goel/Harms. For atypical anatomy there are possible alternative screw pathways in C2. These alternatives include the use of intralaminar screws, pars interarticularis screws or anterior transarticular screws.Material and Methods:Eight human cervical spines (segments C0-C3) were tested in flexion/extension, lateral bending and axial rotation. Range of Motion (ROM) at a 1.5 Nm load was recorded. After native testing, the Harms (HARMS), pars screw (PARS), intralaminar screw (INTRA) and anterior transarticular screw (ATA) constructs were applied in a random order. Results:All instrumentation techniques were able to reduce ROM for most of the motions. The differences between the techniques were small. Nevertheless, the intralaminar screw showed deficits in lateral bending. Conclusion:Screw positioning seems to be of minor influence on stability in atlantoaxial stabilization. Therefore, the pars screw is a sound alternative to the established techniques from a biomechanical point of view. Anatomical considerations for screw placement should be kept in mind as a superior priority.

Corresponding author : mehmet bulent Onal