LAUSR

To investigate the application of a “personalized” guide plate for pedicle screw insertion in the thoracolumbar spine of patients with ankylosing spondylitis using three-dimensional printing. Twenty ankylosing spondylitis patients with a thoracolumbar vertebral fracture were examined using computed tomography. Anatomic digital imaging and communications in medicine data was reconstructed to stereolithography data through M3D software. Three-dimensional printing was done using fused deposition modeling. The length and diameter of pedicle screw, angle between the pedicle screws and the horizontal plane, angle between the PS and the sagittal plane, and distance between the entry position and midline were measured based on three-dimensional printing. Time of operation, intraoperative blood loss, postoperative drainage volume, time of nailing, time of radiation exposure and Japanese orthopedic association scores were also recorded. No significant difference between the preoperative predicted value and actual values of the pedicle screw was found in the three-dimensional printing group for length and diameter of pedicle screw, angle between the pedicle screw and the horizontal plane, angle between the pedicle screw and the sagittal plane and distance between the entry position and midline. The Time of operation, intraoperative blood loss and postoperative drainage volume of the three-dimensional printing group were significantly better than those of the non- three-dimensional printing group. Moreover, the time of nailing and time of radiation exposure of patients in the three-dimensional printing group were significantly shorter than those of the non-three-dimensional printing group. Japanese orthopedic association scores at 1, 2 and 4 w after surgery in the three-dimensional printing group were significantly higher than those in the non-threedimensional printing group, but there was no significant difference between groups at 6 mo. A personalized guide plate constructed by three-dimensional printing could assist thoracolumbar pedicle screw insertion in ankylosing spondylitis patients.