An anatomical study comparing standard fluoroscopy and virtual fluoroscopy for the placement of C1-2 transarticular screws.

OBJECT The authors sought to compare radiation exposure, surgical time, and accuracy of screw placement when using either standard fluoroscopy or virtual fluoroscopy for the placement of C1-2 transarticular screws. METHODS Twenty-two C1-2 transarticular screws were placed in 11 cadavers in a randomized and alternating order by using either standard fluoroscopy or virtual fluoroscopy (fluoronavigation). The radiation time, procedure time, and accuracy of screw placement were recorded and statistically compared. A small but statistically significant reduction in fluoroscopy time was noted with the virtual fluoroscopy technique but the surgical times were similar between the two techniques. The incidence of noncritical and critical breaches (those at risk of causing a neurovascular injury) was not significantly different between the two groups. Careful analysis of the C1-2 anatomy in these specimens underscored the importance of placing the screw path in a maximally dorsal and medial portion of the C-2 isthmus to avoid injury to the vertebral artery and to maximize the bone purchase of the C-1 lateral mass. CONCLUSIONS Although virtual fluoroscopy may represent a useful tool for transarticular screw placement, it does not supplant traditional surgical techniques and does not appear to lower the incidence of bone breaches that can occur when performing this demanding procedure.