The Experimental Study Of Natural Orifice Translumenal Endoscopic Surgery

Backgroud:Natural Orifice Translumenal Endoscopic Surgery (NOTES) is not through the skin incision,but by the body’s natural cavity.NOTES is performed using flexible endoscopes by an access of the hollow organs. NOTES has no abdominal wall incision,less postoperative pain,shorter hospitalization time, save the hospitalization cost,better cosmetic results and other petential advantages. NOTES research has made a lot of progress at home and abroad,but NOTES mostly remain in the animal experiments and still faces many problems to clinic. With the improvement of equipment and technology,NOTES will certainly bring a new era of minimally invasive surgical.Objective:Our group begin to sduty NOTES in2009,we have preliminary evaluated the safety and feasibility of NOTES,and provid practical experience and theoretical basis for the furfher development of NOTES research.we explore how to avoid intraperitoneal infection further more in this study,how to select and locate a position of the access in trasgastric cholecystectomy.we compare the closures of the access in different ways, then analyze and summarize the feasibility, healing of full-thickness and inflammatory response about different closures.Method:30WuZhiShan miniature pigs were involved in this study. The pigs were deprived of food for24h before surgery. General anesthesia was induced to all animals, then endotracheal intubation and mechanical ventilation. Then a sterile double-channel video endoscopy was inserted into the stomach, The gastrotomy site was carefully chosen by observation of the indentation on the gastric wall produced by palpation of the anterior abdominal wall. The endoscopy was inserted into the peritoneal cavity through the access, then we perform the cholecystectomy.This experimental study includes three parts. In the first part,10porcines were invidided into two groups randomly, The control group has4pigs and the study group has6pigs. The two groups were completed abdominal exploratory surgery. The control group was lavaged with saline, the other group was lavaged with betadine of1:10and pumped after3minutes.5ml gastric juice(sample A) and lavaged fluied (sample B) were collected before and after lavage respectively and5ml of peritoneal fluid(sample C) was collected at the end of the procedure of NOTES. Specimens were submission bacterial culture and identification.All animal of the two groups were detect WBC and CRP before surgery, the end of surgery and the postoperative day of1,3,7. In the second part,20porcines were invidided into A and B groups randomly.Group A uses EUS to scan the stomach cavity and then select a safe location as access position in the lesser curvature of the anterior wall of the stomach. Group B chooses the lesser curvature of the anterior wall of the stomach near the pyloric part1-2cm as the access position under endoscopic, then complete cholecystectomy after into abdominal cavity. Operation time of cholecystectomy were compared between the two group, the number of cases that different from expected position, bleeding in the process of make a incision and damage of around organs were compared. In the second part, survival animals in the second experiment were randomly divided into C, D two groups. The10pigs in group C were used endoclips to close the gastrotomies, and the other9pigs in group D were used endoloop and endoclips to close the gastrotomies. Record the operation time and the success rate of two closure ways. Observe the animal if there was a clinical peritonitis after the gastrotomies were closed, whether there were intraperitoneal adhesions and abscess around the access after necropsied. The specimens were observed directly whether the incision is complete healing, and then observed under the microscope, whether the mucosa, submucosa and muscular were complete healing, if there were signs of infection and ulcers.Result:Experiment one,10cases were successfully complete NOTES abdominal exploration, success rate is100%(10/10). The inflammatory in SG was less than the CG in the hematologic indicators, the bacterial culture results showed that E.coli is the most. The average bacterial load of the fluid before lavage was18.0×103CFU/ml.And the average bacterial load of the fluid after lavage after NOTES were3.3X 103CFU/ml and7.1×103CFU/ml in the control group. There were0CFU/ml and8.1CFU/ml in the study group after the betadine lavaged(P<0.05). Experiment two, group A was time-consuming than group B in the operation of making incisions (25min\15min), but in the operation of cholecystectomy group A was more time-saving (73min\95min).The position of all accesses was same as expected in group A, there were3cases different from the expected location in group B.And there was one case that the access position was in the greater curvature of stomach, this had brought a difficult factor in endoscopic cholecystectomy, this experimental animal had died because of long time operation. Group A was significantly less than group B in the incidence of complications, there was statistical significance (P<0.05).Conclusion:1、Endoscopic abdominal exploration and biopsy were not difficult in existing endoscopic equipment, but the operation of intra-abdominal surgery faces some difficulties.2、Preoprative gastrointestinal lavage was effective in reducing the incidence of abdominal infection, the use of saline lavage can significantly reduce the count of bacteria, and betadine solution lavage was reached sterile state.3、EUS can observe the specific location of the target organ and the relationship between the stomach wall and surrounding organs, even can observe the blood signal of the stomach wall. This can select an appropriate incision to avoid damage to surrounding organs and blood vessels.4、The closure using endoscopic clip was not very safe, and the rate of full-thichness healing was not hing, some small abscess was formed around the incision.5、The method of endoloop combined with endoclip was safe and effective, and easier to operate than pure endoclip.Most of incisions healed full-thichness, and there were no severe inflammatory reaction under the microscope and adhesions around the incision.