Techniques for predicting and avoiding unintentional biplanar movements during iliosacral screw placement

The technique for placing iliosacral screws typically involves the surgeon using an inlet and outlet view as the primary means for assessing the anteroposterior and craniocaudal position of the guidewire, respectively. However, because these views are rarely, if ever, orthogonal to one another, this technique will inevitably lead to unintentional biplanar movements. These unintentional movements, in turn, require correction, which can increase operating room and fluoroscopic time. Here we calculate the degree and magnitude of these unintentional movements. Additionally, we provide a simple technique for minimizing or eliminating them altogether.