Abstract: Objective  To investigate the accuracy and safety of lumbar pedicle screw placement reference the spine process and the vertebral rim.
  Methods  Eighty-two patients with lumbar spinal stenosis were enrolled and treated with posterior lumbar interbody fusion. According to the pedicle screw placement method, patients were divided into observation group(43 cases) and control group(39 cases). The pedicle screw was placed reference to the spinous process and the vertebral rim in observation group, and it was inserted according to the Magerl method in control group. The operative time, intraoperative blood loss, incision length, intraoperative fluoroscopy times, the accuracy of the nail placement, the relationship between the screw and the pedicle cortex, and the complications were recorded and compared.
  Results  All patients were been operated successfully. The incision length in observation group was significantly longer than that in control group(P＜0.05). There was no significant difference in operative time, intraoperative blood loss, fluoroscopy times, and the accuracy of nail placement between two groups (P＞0.05). The VAS score at one month after surgery was significantly lower than the figure at one week after surgery(P＜0.05). There was no significant difference between two groups at one week and one month after surgery(P＞0.05). The relationship between screw and pedicle cortex in observation group was better than that in control group(P＜0.05). There was no significant difference in the occurrence of complications between two groups(P＞0.05).
  Conclusion  Compared with the Magerl method, the new nailing method can obtain the same accuracy of nail placement, but the relationship between the screw and the pedicle cortex is better. It provided a new solution and choice for the placement of pedicle screws.

Key words: spinal stenosis； pedicle screw, fiducial markers