Abstract: Objective:To compare the perioperative and recent curative effects of laparoscopic radical resection of low rectal rectal carcinoma by natural orifice specimen extraction surgery(NOSES) with two-step procedure to turn rectum out from the abdominal cavity and traditional one-step procedure to turn rectum out from abdominal cavity. Methods:The clinical data of 63 patients who were treated by laparoscopic radical resection of low rectal rectal carcinoma by NOSES were analyzed retrospectively. A total of 39 patients were treated with the method of two-step procedure to turn rectum out from the abdominal cavity (two-step procedure group)and 24 patients were treated with the traditional one-step procedure to turn rectum out from the abdominal cavity(traditional one-step procedure group). Results:The maximum tumor diameters, the successful rates, tumor fragmentation rates, operation time, intraperative bleeding loss, postoperative exhaust time, anastomotic leakage rates after operation,and the short-term-follow-up results of the patients in two groups were recovered. The specimens of 39 patients in two-step procedure group were successfully pulled out from the anus, the anastomosis was finishehed after resection, and the NOSES of low rectal carcinoma was successfully completed,while 3 cases were failed of 24 cases in traditional one-step procedure group, the successful rate was decreased(P=0.024).After the specimen were pulled out from the anus,the fragmentation rate of the patients in two-step procedure group was lower than that in traditional one-step procedure group (P=0.004). The operation time of the patients in two-step procedure group was less than that in traditional one-step procedure group (t=4.266,P<0.01).There were no significant differences in the maximum diameters of tumor(t=-0.406,P=0.686),intraoperative bleeding loss(t=1.799,P=0.075), postoperative exhaust time (t=-0.144,P=0.886), postoperative anastomotic leakage rate(P=1.000)of the patients between two groups. During 3 to 24 months of follow-up,there were no significant differences in the recurrence rate(P=0.140) and metastatic rate of carcinoma (P=0.36) of the patients between two groups. Conclusion:Two-step procedure to turn rectum out from the abdominal cavity can reduce the pressure on the tumor during turning the rectum out,which can save the operation time and get good short-term curative effect during the radical resection of low rectal carcinoma by NOSES.

Key words: rectal neoplasms, two-step procedure to turn rectum out, natural orifice specimen extraction surgery, recurrence rate, metastatic rate