Abstract: BACKGROUND: In recent years, with the development of 3D printing, surgical surgery has become personalized and accurate. 3D printed guide template technique can realize preoperative planning and intraoperative navigation, making surgery more accurate. In clinical orthopedic surgery for moderate and severe stiff scoliosis, there is still a problem that the accuracy of screw placement is not high, resulting in screw loosening and even nerve complications. There are few studies on 3D printed guide template technique to guide screw placement in surgery for severe stiff scoliosis.  
OBJECTIVE: To evaluate the clinical effect of the 3D printed guide template technique combined with multiple posterior derotation in the treatment of severe rigid scoliosis.
METHODS: The clinical data of six patients with severe scoliosis undergoing 3D printed guide template technique of pedicle screw combined with multiple posterior derotation were retrospectively analyzed. There were 3 males and 3 females, with a mean age of (18.17±3.49) years (range, 15-23 years). The changes of parameters related to lateral bending were analyzed at postoperative 2 weeks and 18 months, and the results were obtained by statistical analysis.  
RESULTS AND CONCLUSION: (1) The operation time was 280-540 minutes (mean 340.83±102.20 minutes). The intraoperative blood loss was 1 000-4 000 mL (mean 2 000.00±1 073.70 mL). The fixed segments were 9-14 vertebral bodies (mean 11.83±1.72), and no screw loosening occurred during the operation. (2) All patients were followed up. At postoperative 2 weeks, the anteroposterior and lateral radiography of the whole spine showed that the cobb angle, the distance between the vertical line of C7 on the coronal plane and the median line of S1, the distance between the vertical line of C7 in the sagittal plane and the posterior edge of S1, apical vertebral translation, thoracic kyphosis, and lumbar lordosis were significantly corrected. The average correction rate of the cobb angle in the main curve was 62.22%. After 18 months of follow-up, there was no significant change in all parameters compared with 2 weeks after operation; the orthopedic effect was satisfactory, and there was no infection or internal fixation fracture. (3) There was one case of delayed wound healing; scar healing appeared after dressing change treatment; no neurological complications occurred. (4) The results show that the 3D print-guide template combined with multiple posterior rod derotation technique is safe and effective in the treatment of severe rigid scoliosis, and the correction effect is satisfactory.

Key words: severe rigid scoliosis, derotation, 3D printed guide template technique, rib resection, CT three-dimensional reconstruction