Trans-rectal natural orifice specimen extraction (NOSE) during laparoscopic anterior resection: Chinese experience with a novel method

Background: To introduce a novel method for double stapling technique in colorectal anastomosis during laparoscopic anterior resection of upper rectal or sigmoid colon cancer with trans-rectal natural orifice specimen extraction (NOSE). Methods: From June 2015 and May 2016, patients with upper-rectal or sigmoid colon cancer who received treatment in Shanghai East Hospital were enrolled. Preoperative and postoperative clinical variables were analyzed and compared between groups. Postoperative pain was analyzed utilizing a visual analog scale (VAS). Postoperative overall survival was analyzed using a K-M curve. Results: A total of 99 colorectal cancer cases were randomly divided into NOSE with novel method group (NOSE, n=48) and conventional laparoscopic group (non-NOSE, n=51). No statistically significant differences in preoperative demographics of the patients as sex, age, body mass index were found among the groups. The NOSE group had the longer operation time, but less blood loss than the non-NOSE group. The NOSE group had no abdominal incision and the lower postoperative VAS score. The time for intestinal function recovery and the length of hospital stay (LOS) was statistically significantly different, with the non-NOSE group having the longer time. The incidence of postoperative complications was lower in NOSE group (5/48, 10.4%) than in the non-NOSE group (8/51, 15.7%), the difference was statistically significant. The K-M survival curve showed no statistically significant difference in the disease free survival rate between the NOSE group and non-NOSE group. Conclusion: NOSE with novel method is safe and feasible to use in patients having colorectal cancer. Compared with traditional laparoscopic surgery, the postoperative complication rates of NOSE surgery were lower with an improved short-term clinical recovery. postoperative variables of operation time, estimated intraoperative blood loss, size of tumor, intestine function recovery, length of hospital stay (LOS), postoperative complications, postoperative pain score. The pathologist determined the integrity of the TME and the pathologic Stage of the rectal cancer. A 10-point visual simulation scale was used for the assessment of the level of pain. The VAS scores on the first three postoperative days were collected and assessed in the two groups. The more severe the pain, the higher the score. test to analyze the between the survival of two groups. P of

cm incision on the abdomen is required for specimen removal and intestinal reconstruction [2] .
Laparoscopic NOSE was first reported by Franklin in 1993 [3] . In 2008, Palanivel was the first to name the no-abdominal incision surgery as NOSE [4] . The innovation of NOSE surgery lies in the removal of specimens from natural orifices and bowel reconstruction with laparoscopy. Compared with the traditional laparoscopic surgery, the surgical trauma of NOSE is significantly reduced, because NOSE surgery is performed without an additional abdominal incision. Previous studies have reported that NOSE surgery has the advantages of a shorter hospital stay and recovery time, compared with traditional laparoscopic surgery [5][6][7] .
NOSE was usually applied for benign tumour or early stage cancer in previous studies, and the methods of these study could not fulfill the principles of a sterile and tumour-free operation [8][9][10][11] . The NOSE with this novel method requires the avoidance of intra-abdominal bacterial contamination and tumour cell shedding. The short-term safety and complication between NOSE surgery and conventional laparoscopic surgery were compared.

Patient selection and clinical variables
From June 2015 and May 2016, 99 patients with colorectal cancer who received surgery in Shanghai East Hospital were randomly divided into two groups using the random number  Operative procedure Laparoscopic colorectal resection was performed in accordance with the principles of total mesorectal excision, and the specific surgical steps and the preparation of the specimen protection sleeve were performed as previously described. Upon completion of intestinal resection, the self-made specimen protection sleeve was inserted through the trocar into the abdomen. The stapler anvil was placed into the abdominal cavity through the protection sleeve. After the specimen was completely contained in the protection sleeve, the protection sleeve was pulled out together with the specimen. A piece of clean gauze was placed under the proximal colonic stump, the edge of the stump was cut off, and the open colonic stump was locally disinfected using iodophor. The stapler anvil was then placed in the colonic stump, and the colonic stump was closed with Hem-o-lok clips. The colonic stump was annularly fixed onto the central rod of the stapler anvil with a snare, and excess colonic tissue was cut away with scissors. A tubular stapler was inserted through the rectum, and the central rod was pulled out from the centre of the rectal stump and closed with the proximal anvil to complete the colorectal anastomosis, as shown in Figure 1.

Statistical analyses
All data were completed using the SPSS 20.0 statistical software. Measurement data were expressed as () and compared with the t test, and the enumeration data were expressed as [n (%)] and compared using a χ2 test. The survival curves were plotted with the Kaplan-Meier method, and the log-rank test was used to analyze the relationship between the survival cycles of the two groups. Any difference with a P value of <0.05 was considered as statistically significant.

Comparison of Preoperative and Postoperative Clinical Indexes among the two Groups
No statistically significant differences were found among the two groups in terms of preoperative indexes such as age, sex, BMI, tumor distance from the anal margin, and serum CEA and CA199 levels. No significant differences in postoperative tumor diameter, lymph node positivite rate, and tumor staging were found among the two groups (P>0.05).

Disease free Survival for NOSE and non-NOSE groups
The patients were followed up for 3 years. The K-M curve analysis revealed no statistically significant difference in overall survival between the NOSE and non-NOSE groups (P= 0.856), as shown in Figure   2.

Discussion
With the popularisation and development of laparoscopic minimally invasive surgical techniques, there have been reports of laparoscopic colorectal surgery with specimens removed through the colon, rectum and vagina [12,13] . The dissociation, separation, pull-out, and reconstruction of the intestine are all completed in the abdominal cavity during laparoscopic AR with NOSE. Laparoscopic AR with NOSE has an advantage over traditional laparoscopic surgery in postoperative recovery [6,14] .
This study described a novel method of NOSE for sigmoid colon and upper rectal cancer. In addition, the safety and clinical recovery of the NOSE surgery were compared with conventional laparoscopic surgery. This study provides a clinical basis for the application of trans-rectal NOSE surgery for colorectal cancer.
This study showed that the short-term clinical efficacy of the NOSE surgery was superior.
Postoperative pain scores in the NOSE group were significantly lower than those in the non-NOSE group. NOSE surgery maintained the integrity of the abdominal wall and protected the function of the abdominal wall. Therefore, the patient's postoperative pain was also relatively lighter, which contributed to the patient's early activities. Because the abdominal cavity was not exposed, there was less intestinal interference in the NOSE surgery than in traditional laparoscopic surgery [14] . Therefore, the time of intestinal function recovery in the NOSE group was shorter than the traditional laparoscopic group. Tumor metastasis at the puncture and incision sites after laparoscopic surgery for colorectal cancer is still a controversial issue [15][16][17][18][19] . Because there is no auxiliary incision on the abdominal wall in NOSE surgery, there is no chance of incision metastasis [20][21][22] . In addition, the incidence of postoperative complications of the NOSE surgery was lower than non-NOSE surgery.
Incision complications such as wound infection are eliminated in NOSE group.
Our experience with novel method for NOSE surgery have three key surgical steps. The NOSE surgery for cancer must be completed in a '1-out and 2-in' manner. Here, '1-out' refers to the removal of the specimen with protection sleeve, and '2-in' refers to the insertion of the anvil into the abdominal cavity and placement in the proximal colon. In the previous study, a specimen protection sleeve was used in the surgery, which provided an excellent solution for the problems associated with specimen removal and anvil introduction into the abdominal cavity [23] . Instead of using the anus and rectum as the route of insertion, this study inserted the protection sleeve through the 12-mm trocar in abdomen, then pulled it out from the rectum in an anterograde fashion, thereby effectively avoiding the risk of contamination during the insertion of the protection sleeve. Before the specimen was pulled out through the protection sleeve, the sterile anvil was placed into the abdominal cavity through the protection sleeve, thus avoiding the risk of intra-abdominal contamination by bacteria or shed tumour cells. A variety of methods have been reported for the placement of the stapler anvil in the proximal colon, which have shortcomings in terms of complicated use or implausible techniques [10][11] . The introduction of the central rod of the anvil into the sterile abdominal cavity from the non-sterile intestinal canal leads to a high risk of abdominal cavity contamination and violates the principle of a sterile operation. In the present study, we inserted the anvil into the proximal colon in an anterograde fashion, and subsequently ligated and fixed the anvil with a snare.
This method is in line with the principle of a sterile operation, and is simple to perform and easy to master. Concurrently, Hem-o-lok clips were used to pre-clamp the colonic stump, which facilitated the complete and secure colonic stump ligation with the snare, thereby preventing the incidence of anastomotic fistula. These three steps were sure to avoid bacterial contamination and tumour cell shedding in the abdominal cavity during NOSE surgery.
In summary, in laparoscopic NOSE, the novel method of stapler anvil placement described in the present study can effectively reduce the risk of intra-abdominal contamination as well as tumour cell shedding and implantation. In addition, the ease and feasibility of use provide great value in the wide clinical application of this method. Minimally invasive techniques and related devices are still at a stage of rapid development, and the consequent concept of minimal invasion will be further advance.
Certainly, laparoscopic AR with NOSE will be performed in an increasing number of patients, which will lead to more reasonable indications and further optimisation of surgical procedures. Hence, there are great prospects in the practical application of our method.

Conclusion
NOSE with novel method include removal of the specimen with protection sleeve, insertion of the anvil into the abdominal cavity through protection sleeve and placement in the proximal colon. This novel method is safe and feasible to use in patients having colorectal cancer. Compared with