The Experimental Study Of Natural Orifice Translumenal Endoscopic Surgery

Background and objective:Natural orifice transluminal endoscopic surgery(NOTES) is a novel surgical technique that performs the diagnosis and therapy for patients via the orifice routes(as transgastric, transcolonic or transvaginal) to the peritoneal cavity without abdominal insicions. NOTES have potiental advantages as following no abdominal insicion, lesser postoperative pain, shorter length of hospital stay and better cosmesis and so on, compared to tranditional open surgery and laparoscopy. So it is regarded as a milestone of mini-invasive surgery and focused by surgeons and gastroenterologists. The NOTES-related experimental and clinical reseach has made significant achievements in western developed countries, unfortunaterly the NOTES study are carried out only in a few hospitals or laboratorys and it is still in the primary stage in our country.To eveluate the feasibility, safety and efficacy of the NOTES to undergo the intra-abdominal surgery, this systemic animal experiment is designed. In the first part, the cholecystectomy is performed in the survival porcines to analysize and summarize the techniques, difficulty and complications of NOTES. In the second part, compared to the traditional laparoscopic surgery, the perioperatively cardiopulmonary and inflammatory response indicators are summarized to eveluate the safety of NOTES. In the third part, we summarize the prevention strategies of the postoperative infection primarily.Methods:30female WuZhiShan small porcines(WZSSP) were involved in the study. The pigs were deprived of food for24h before surgery. General anesthesia was induced to all animals with intravenous(IV) propofol10ml/30kg and pancuronium2ml. 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 or the colotomy was produced in the sigmoid colon15-20cm from the anal verge. Aneedleknife was used to make a incision on the natural orifice wall, which was enlarged with a dilation bolloon. Then the endoscopy was inserted into the peritoneal cavity through the access or the hybrid cholecystectomies were performed. In the first part,20porcines were invidided into two groups randomly and received cholecystectomies with the total transgastric NOTES (group A)or laparoscopic assistance(group B), to summarize the the feasibility, safety and efficacy of the NOTES to undergo the intra-abdominal surgery. In the second part, all of animals in the first part were divided into two groups before the NOTES respectively, i.e. a gastric lavage was performed before NOTES with1,500-2,000ml of sterile saline solution0.9%in group A1and B1and the gastric lavage wasn’t performed in group A2and B2. Gastroscope and peritoneal fluid aspirates in each animal were obtained prior to and after the gastrotomy. Each sample was sent for bacterial colony counts, culture, and identification of species. In the third part,10WZSSP were divided into two groups, i.e. the laparotomy was performed by the total NOTES through the oral access and the pneumoperitoneum were created with the endoscopic insufflation (N group) or by the traditional laparoscopy and the pneumoperitoneum were created with the standard autoregulated laparoscopic insufflator using carbon dioxide(CO2)(F group). In this part, the the perioperatively cardiopulmonary and inflammatory response indicators of each group were collected and summarized.Results:In the first part, the cholecystectomy were successfully performed in12porcines and the success rate was60%.5in group A and7in group B respectively. In the second part, the specimens of19of20animals in the first part were performed NOTES through the stomach. There was no significant difference between both groups on the average platelet preoperatively and postoperatively. However, the white blood cell(WBC) on the postoperative day1and3in the group A1and B1were significant lower than in the group A2and B2. There was no different on the bacterial species bwtween two groups, however, there were fewer bacterial contamination on Contaminated peritoneum sample after NOTES(sample C) in the former two groups than in the other two(30.0%vs55.6%). In the third part, all of10porcines were performed laparotomy by NOTES or laparoscopy without periopera-tive and postoperative complications. There was no significant difference between both groups on the perioperatively and postoperatively average heart rate and arterial blood pressure(ABP). There was no significant difference between both groups on the postoperatively average interleukin-1(IL-1) except on the postoperative day3. And the average tumor necrosis factor-a(TNF-a) on the postoperative day1and3in the group N were significant higher than in the group F. The IL-1and TNF-α on the postoperative day7in both groups were reduced to the normal level almostly.Conclusions:①Using the total transgastric or transcolonic route to expore the peritoneal cavity is feasible with safety, however, it is difficult to performed cholecystectomy using the present endoscopic instruments;②The hybrid approach increases safety of natural orifice wall incision, improves orientation and navigation of the flexible endoscope inside the peritoneal cavity, simplifies NOTES;③The natural orifice wall incision was closed with endoscopic clips is safe to most of animals, however, there are some failures which may lead to gastric and intestinal lavage and peritonitis;④compared to the trditional laparoscopic laparotomy, using the present endoscopic insufflation to create the pneumoperitoneum, the trauma to the experimental animals of the natural orifice translunimal endoscopic laparotomy is much more;⑤The gastric lavage using sterile saline solution before NOTES is one of the effective method of disinfection;⑥It is difficult to performed surgery into the peritoneal cavity using the endoscopic instruments, so much endoscopic instruments need to be improved to show the potential advantages of NOTES.