Immediate postoperative stability of the atlantoaxial articulation: a biomechanical study comparing simple midline wiring, and the Gallie and Brooks procedures.

A biomechanical study was undertaken to quantitate the immediate postoperative stability of the atlantoaxial articulation after stabilization by simple midline wiring, as well as the Gallie and Brooks procedures. Fresh adult cadaveric cervical spines were mounted for testing such that only the C1-2 motion segment and the load deflection curves generated in flexion, extension, and torsion moved. Spines were tested after the creation of a fracture at the base of the odontoid process with transection of the transverse ligament and after stabilization by each of the surgical techniques. Mean apparent stiffness values evaluated the biomechanical properties of these three commonly performed procedures. Although all tested procedures restored supraphysiologic mechanical properties in all modes tested (p less than 0.001), the Brooks technique was stiffer than the other two methods (p less than 0.001). Although many factors must be considered when selecting a particular surgical technique, the biomechanical data obtained in this study may be of assistance to the surgeon in choosing the type of construct for upper cervical stabilization and arthrodesis.