Authors: Kota Kojima Shunji Asamoto Yoshiomi Kobayashi Masayuki Ishikawa Yasuyuki Fukui
Publish Date: 2015/05/29
Volume: 157, Issue: 7, Pages: 1173-1178
Abstract
Cortical bone trajectory CBT a relatively new technique for pedicle screw insertion in the lumbar spine is believed to have equivalent pullout and toggle characteristics compared with the traditional trajectory TT It has been hypothesized that the new trajectory offers higher cortical bone contact with the pedicle screws and therefore has an improved anchoring property over the traditional trajectory where the screws are inserted into the vertebral body trabecular space The aim of this study is to evaluate the pedicle screwcortical bone contact between the two trajectories from a radiological standpointTwo hundred twentytwo patients with degenerative lumbar spine disease underwent computed tomography scanning For each patient axial slices of the L4 and L5 vertebra were cut in two planes one horizontal to the pedicle representing the plane at which pedicle screws are inserted using the TT and another in a more caudocranial plane representing the plane at which pedicle screws are inserted using CBT For each trajectory a region of interest ROI was selected within the area in which the screws are inserted A CT number Hounsfield scale was then calculated within each ROI to compare the bone densityThis study has demonstrated that with the cortical bone trajectory the pedicle screws penetrate a region that is richer in cortical bone compared to when using the traditional trajectory This is in keeping with previous hypotheses that the new trajectory offers higher cortical bone contactAll authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest such as honoraria educational grants participation in speakers’ bureaus membership employment consultancies stock ownership or other equity interest and expert testimony or patentlicensing arrangements or nonfinancial interest such as personal or professional relationships affiliations knowledge or beliefs in the subject matter or materials discussed in this manuscript
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