- Discussion:
- allow control of Anterior column via a posterior approach;
- provide 4 point fixation;
- reduce the number of levels that must be incorporated in the construct;
- this is a particular adavantage in the lower lumbar spine;
- screws provide lever arms, which facilitate reduction maneuvers and allow lordosis to be maintained;
- allows saggital plane correction;
- because limitations are imposed by pedicle diameter, these systems are best used for L2 to L5 levels