TY - JOUR AU - Tsai, Wen-Chi AU - Chen, Po-Quang AU - Lu, Tung-Wu AU - Wu, Shing-Sheng AU - Shih, Kao-Shang AU - Lin, Shang-Chih PY - 2009 DA - 2009/04/30 TI - Comparison and prediction of pullout strength of conical and cylindrical pedicle screws within synthetic bone JO - BMC Musculoskeletal Disorders SP - 44 VL - 10 IS - 1 AB - This study was designed to derive the theoretical formulae to predict the pullout strength of pedicle screws with an inconstant outer and/or inner diameter distribution (conical screws). For the transpedicular fixation, one of the failure modes is the screw loosening from the vertebral bone. Hence, various kinds of pedicle screws have been evaluated to measure the pullout strength using synthetic and cadaveric bone as specimens. In the literature, the Chapman's formula has been widely proposed to predict the pullout strength of screws with constant outer and inner diameters (cylindrical screws). SN - 1471-2474 UR - https://doi.org/10.1186/1471-2474-10-44 DO - 10.1186/1471-2474-10-44 ID - Tsai2009 ER -