Adjustment of Suboptimally Placed Lumbar Pedicle Screws Decreases Pullout Strength and Alters Biomechanics of the Construct: A Pilot Cadaveric Study

Great care is warranted in the initial placement of lumbar pedicle screws. Revising a nonparallel screw placement decreases pullout strength and alters biomechanical movements (axial rotation and flexion/extension) in patients with decreased bone mineral density. If a screw is inadvertently placed nonparallel to the endplate but is within the confines of the pedicle and vertebral body with adequate bone purchase, it should not be revised and rather be left in its place.