Bone graft translation of four upper cervical spine fixation techniques in a cadaveric model

The goal of spinal fixation is to promote bony fusion by restricting motion at the site of the bone graft. In order to evaluate the efficiency of various cervical fixation techniques, the authors determined the translations at the posterior arch of C1 for four C1 -C2 posterior techniques: Gallie, Brooks, Mageri, and Halifax. The authors assumed that translational laxity is the critical motion parameter and evaluated this parameter, quantified herein as the neutral zone, at seven points at the graft site. The authors found that there was no significant difference with the fixation techniques in the average axial translation. In shear, the Mageri averaged 1 mm which was significantly less than the Gallie (2.1 mm). The authors propose that evaluation by translational laxity (neutral zone) at the graft site is a noteworthy concept in biomechanical analysis