Sumiya S, Numano F, Ogawa T, et al. - In this retrospective analysis, researchers sought to compare the accuracy of percutaneous pedicle screw (PPS) insertion (P-side) with that of conventional open screw insertion (O-side) during unilateral open transforaminal lumbar interbody fusion (TLIF) in the same patients, and to ascertain the incidence of pedicle screw misplacement and to distinguish relevant risk factors. This study obtained prospectively collected data of 766 pedicle screws placed involving 181 consecutive individuals who had undergone an unilateral open-TLIF technique in the lumbosacral spine. The outcomes of this study displayed that accuracy of pedicle screw insertion was not significantly different between PPS insertion and conventional open screw insertion in the same individuals. It was indicated that body mass index had a significant influence on the risk of screw misplacement in PPS insertion.