The purpose of this study was to evaluate the change of lumbar lordosis before and after pedicle screw fixation. Authors analyzed the change of lumbar lordosis in 100 cases of degenerative spinal stenosis, which were operated on using pedicle screws f...
The purpose of this study was to evaluate the change of lumbar lordosis before and after pedicle screw fixation. Authors analyzed the change of lumbar lordosis in 100 cases of degenerative spinal stenosis, which were operated on using pedicle screws from January 1994 to July 1996. We also measured the total lordosis angle(TLA) and segmental lordosis angle(SLA) according to the fusion types and the fusion segments. Total lumbar lordosis angle was measured from the upper endplate of the first lumbar vertebra to the upper endplatee of the first sacral vertebra. And the segmental lordosis angle was measured from the upper endplate of the upper-most vertebra in fusion segments to the upper endplate of the lower-most vertebra. In all patients, mean TLA was 33.6 degrees preoperatively, 37.9 degrees postoperatively and 36.1 degrees in last follow-up.
The TLA according to fusion types mostly change in the six and seven decades of two groups (floating, fixed fusion group). The TLA and the SLA according to fusion segments mostly changed in 5 segments fusion group and the change according to fusion types was not.
In pedicle screw fixation, physiologic lordosis can be maintained by using the four-poster frame. Preoperative hypolordosis can be corrected into physiologic lordosis by pre-bending technique of the rod. But excessive pre-bending of the rod for correction of the lordosis increased the possibility of loosening of the sacral screws.