Anterior to posterior screw fixation
Posterior column fixation relies primarily on screws placed from the anterior column directed posteriorly.
When possible, it is desirable to place the posterior column fixation through the pelvic brim plate. The most posterior screw (ca 80 mm) is directed toward the ischial spine. It is usually possible to place a second screw (ca 100 mm) in the next anterior plate hole, directed toward the ischial tuberosity.
It may be necessary to place a screw outside of the plate instead. This screw typically starts just lateral to the pelvic brim plate at the level of the angle of the sciatic notch.
Regardless of configuration, it is important that at least two screws be used for the posterior column fixation. A single screw does not provide sufficient torsional stability.