Objective To investigate the application value of stereotactic digital naviga-tion system assisted three‑dimensional (3D) laparoscopic total mesorectal excision (TME) for rectal cancer.

Methods The retrospective and descriptive study was conducted. The clinicopathological data of a healthy volunteer recruited by the Second Affiliated Hospital of Army Medical University and 3 patients who underwent stereotactic digital navigation system assisted 3D laparoscopic TME for rectal cancer in the Second Affiliated Hospital of Army Medical University from May to September 2019 were collected. The healthy volunteer was male, aged 25 years. Of the 3 rectal cancer patients, there were 2 males and 1 female, with the age of 48 years, 63 years and 67 years, respectively. Ten special patches were placed at the anterior superior iliac spine, pubic tubercle and pubic symphysis of the volunteer's bilateral inguen as skin reference points in intraoperative localization and system registration. On the day of operation, patients were placed 10 special patches as skin reference points according to the test results of the volunteer and were completed the enhanced scan of totally abdominal computed tomography examination. Seven fixed anatomical markers in the abdominal cavity of the patients, including abdominal aortic bifurcation, sacrum scapula, bilateral anterior superior iliac spine, bilateral intersection of ureter and iliac artery and median point of peritoneal reflection, were selected for verifying the accuracy of the correspondence between the instrument tip and the system image. Patients underwent 3D laparoscopic TME for rectal cancer assisted by stereotactic digital navigation system. Observation indicators: (1) test results; (2) surgical situations; (3) accuracy of stereotactic digital navigation system. Measurement data with normal distribution were represented as Mean±SD.

Results (1) Test results. The 10 skin reference points of the volunteer were successfully registered in the stereotactic digital navigation system, with the registration error of 2.8 mm. (2) Surgical situations. All the 3 patients underwent stereo-tactic digital navigation system assisted 3D laparoscopic TME for rectal cancer successfully. The operation time of the 3 patients were 193 minutes, 175 minutes, 210 minutes, respectively, in which the set time of the stereotactic digital navigation system were 34 minutes, 25 minutes, 45 minutes, respectively. The volume of intraoperative blood loss of the 3 patients were 60 mL, 30 mL, 80 mL, respectively. Results of postoperative pathological examination showed 3 patients with adenocar-cinoma, including 1 case with mucinous adenocarcinoma. The tumor diameter and the numbers of lymph nodes dissected of the 3 patients were 2.3 cm, 1.5 cm, 4.0 cm and 12, 12, 13, respectively. No patient had lymph node metastasis. The 3 patients in preoperative clinical TNM stage cT3bN0M0, stage cT4aN1M0, stage cT3bN1M0 were in yield pathological TNM stage ypT1N0M0, stage ypT4aN0M0, stage ypT2N0M0 after neoaduvant chemotherapy, respectively. No patient had complication, and the duration of postoperative hospital of the 3 patients was 7 days, 6 days, 7 days, respectively. (3) Accuracy of stereotactic digital navigation system. The registration errors of the skin reference points were 2.8 mm, 2.6 mm, 2.9 mm and the accuracy errors of the abdominal cavity reference points were (2.5±0.4)mm, (2.3±0.7)mm, (2.6±0.6)mm for the 3 patients.

Conclusion The stereotactic digital navigation system assisted 3D laparoscopic TME for rectal cancer is safe and feasible.