Pedicle screw accuracy and the ramifications of imperfect screw placement.

COMMENTARY ON: Oh HS, Kim JS, Lee SH, et al. Comparison between the accuracy of percutaneous and open pedicle screw fixations in lumbosacral fusion. Spine J 2013;13:1751-7 (in this issue). Costa F, Villa T, Anasetti F, et al. Primary stability of pedicle screws depends on the screw positioning and alignment. Spine J 2013;13:1934-9 (in this issue).