The Investigation Of Natural Orifice Translumenal Endoscopic Surgery (NOTES) In Experimental Models

Backgrounds and Objectives:Natural Orifices Translumenal Endoscopic Surgery(NOTES) is a relatively new concept describing endoscopic procedures performed via natural orifices(stomach,colon or vagina) without skin incisions. NOTES seems to provide a large potential benefits over currently available surgical interventions,such as improved cosmesis,decreased incidence of wound infection,decreased need for sedation,decreased incidence of incisional hernias and so on.On March 13,2007,the first clinical transvaginal cholecystectomy was performed in a 43-year-old female patient with symptomatic cholelithiasis by J.Marescaux's group in France,which indicated a new era of minimally invasive surgery coming.Despite accumulated significant NOTES-related knowledge more systematic studies are necessary before translumenal procedures can be recommended into the clinical practice.Unfortunately in our country,the NOTES study is still in the elementary stge.To evaluate the models,techniques,outcomes,pitfalls,and applicability to the natural orifice translumenal endoscopic surgery(NOTES) for performing intra-abdominal surgery,systemic animal experimental studies were designed in this project.In the first phrase,the exploration and multiple procedures were performed on live animal model of wuzhishan small pork(WZSSP) to gain more knowledge and experience.In the second phrase,the transgastric cholecystectomy with the assistance of a tissue forcep introduced through an infraumbilical port was performed on live animal model of mongrel dogs to investigate the feasibility,safety and efficiency.Meanwhile,the role of omentum tamping for gastrotomy closure was investigated compared with endoclips closure.Methods:30 female WZSSPs and 12 mongrel dogs were involved in the study. Gastrotomies or colotomy were performed using a needle knife to make an initial gastric incision,which was usually enlarged with either a sphincterotome or dilation balloon.Then,the endoscope inserted into the abdominal cavity through the access via mouth or anus and the pneumoperitoneum were created with endoscopic insufflation to allow visibility of the working space subsequently. The NOTES procedures included abdominal exploration,liver biopsy,tubal ligation,oophorectomy gastrojejunal anastomosis and cholecystectomy were attempted with or without the laparoscopic assistance on 20 WZSSPs in the first phrase.In the second phrase,the transgastric cholecystectomy with the assistance of a tissue forceps introduced through an infraumbilical port was performed on 12 mongrel dogs.We compared the efficacy of gastrotomy closure between omentum tamping and endoclips closure at last.Results:32 procedures were finished in the project,7 non-survival experiments and 25 survival experiments.In the first phrase,3 times per-orally route,2 times transanusly route and 15 times hybrid technique of laparoscopic assistance pre-orally procedures were performed.In the diagnostic peritoneoscopy,the liver, gallbladder,spleen,stomach,colon,part of intestine,bladder,tubal uterine, ovary,abdominal wall,diaphragm and omentum could be visualized through per-orally route or transanusly route.The success of NOTES procedures included liver biopsy(4/4),tubal ligation(6/6) and oophorectomy(6/6) and cholecystectomy(3/7) through single route or with the assistance of laparoscopy. The unsuccessful procedures included retroperitoneal exploration(0/3) and gastrojejunal anastomosis(0/2).In the second phrase,12 times NOTES Cholecystectomy were performed.Except 2 excluded procedures,once due to instruments damages,once due to the primary disease and celiac adhesion, among 10 times finished procedures,8 animal models survived 2w postoperation. The success rate of omentum tamping for gastrotomy closure was better than endoclips closure(93%vs.50%).Conclusions:The per-orally route and treasonously route peritoneoscopy is feasible with safety to explore the celiac organs like liver,gallbladder,spleen, stomach,colon,part of intestine,bladder,tuba uterine,ovary,abdominal wall, diaphragm and omentum,but the exploration to the retroperitoneal cavity appears difficult.The female reproductive procedures were able to be successfully completed in animal models of WZSSPs using per-orally route, transanusly route respectively with safety.Laparoscopic assistance could facilitate these procedures.The laparoscopic assisted NOTES Cholecystectomy is fastidious and complex,and the success rate was low because of the anatomic variability in WZSSPs.Dissection and mobilization of the gallbladder was feasible and safe in the transgastric NOTES with the assistance of a tissue forceps introduced through an infraumbilical port in mongrel dogs model. Omentum tamping was an effective and convenient for gastrotomy closure with safety.