Objective:To explore the application of 3D printing technology combined with CPBL teaching mode in the teaching of master's degree in spine surgery.Methods:42 postgraduates in our department were randomly divided into two groups: experimental group (21) and control group (21). The experimental group used 3D printing technology combined with CPBL teaching mode as teaching techniques. Before class, the teacher would select some typical cases and design related problems. During class, 3D models were used to guide students to think and solve related problems; The control group used traditional teaching mode. Students in the two groups were compared for the theoretical knowledge and operational techniques they have mastered, and the students' satisfaction and recognition towards different teaching modes were obtained through questionnaire survey. Independent sample t-test was performed using SPSS 25.0.Results:The scores of the theoretical knowledge, operational techniques, teaching satisfaction and recognition of postgraduates were (84.7±3.4), (87.1±3.7), (9.7±0.3), (9.3±0.4) in the experimental group, and (79.7±3.3), (80.4 ± 4.0), (8.4±0.7) and (8.3±0.6) in the control group. The difference between the two groups was statistically significant ( P<0.05). Conclusion:The new teaching mode of combining 3D printing technology with CPBL teaching mode is better than the traditional teaching mode, which is worth further promotion and application.

Objective: To investigate the clinical value of gallbladder-preserving cholelithotomy by natural orifice transumbilical endoscopic surgery on patients with cholecystolithiasis. Methods: A retrospective study was performed on data of 15 patients with cholecystolithiasis, who underwent gallbladder-preserving cholelithotomy by natural orifice transumbilical endoscopic surgery from April 2018 to July 2018. The operative data, including situation of operation, operative time, intraoperative hemorrhage, and postoperative complications were recorded. Results: The procedure was performed successfully in all patients with a mean operative time of 108±12 min (ranged from 92-129 min). The intraoperative hemorrhage was 10-30 mL. Eight patients suffered from slight right upper abdominal pain, and 7 patients felt slight pain in umbilical a week after surgery. No fever, incision infection, umbilical hemia, peritonitis, and ascites were reported. The clear-liquid diet was recommended for one day after operation, and postoperative activity was allowed since the second day after operation. All patients were discharged on the fourth or fifth day, and all recovered to their normal life at one week after discharge. Follow-up showed that the scar was small and hidden in umbilical without visible incision after one month. Ultrasonic examination results showed that gallbladder contractile function worked perfectly in four patients and no gallbladder stone was found after three months. Conclusion Gallbladder-preserving cholelithotomy by natural orifice transumbilical endoscopic surgery is a safe and effective option for patients with cholecystolithiasis, provides excellent cosmetic outcomes, and can be appropriately carried out under the strict control of surgical indications.