Modified Gallie technique versus transarticular screw fixation in C1-C2 fusion

The effectiveness of a modified Gallie technique versus Magerl and Seeman t ransarticular screw fixation was compared in the management of 27 patients with symptomatic atlantoaxial instability, Twelve patients were treated usi ng a modified Gallie technique and postoperative halo vest immobilization. Atlantoaxial arthrodesis occurred in seven (58%) patients, stable fibrous u nion occurred in one patient, and pseudarthrosis with recurrent instability developed in four (33%) patients. Average followup was 6.9 years. All 15 p atients treated using Magerl and Seeman transarticular screw fixation and p ostoperative soft collar immobilization had atlantoaxial arthrodesis develo p. Average duration of followup was 4 years. One patient sustained vertebra l artery injury during preparation for screw placement, Magerl and Seeman t ransarticular screw fixation provides stability and more reliably produces atlantoaxial arthrodesis than the Gallie technique provides in patients wit h atlantoaxial instability without the need for rigid postoperative bracing . Potential for vertebral artery exists despite apparent accurate screw pla cement. To ensure that safe transarticular screw placement is possible, pre operative fine cut axial computed tomography with reconstructions Is requir ed to assess vertebral artery position and C2 isthmus anatomy. A proportion of patients have anatomy unsuitable for screw placement. Traditional wirin g techniques are indicated in these patients.