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Background: Diagnostic natural-orifice transluminal endoscopic surgery (NOTES) peritoneoscopy can easily be performed with standard endoscopic equipment in animal studies. The efficacy and optimal transgastric site for NOTES access in humans, however, has not been determined., Objective: To characterize the efficacy of various anterior gastric access locations for diagnostic transgastric NOTES peritoneoscopy in humans., Design: Prospective clinical study., Setting: Tertiary-care center with experience in NOTES peritoneoscopy., Patients: Patients undergoing planned laparoscopic gastrectomy or gastrotomy involving the anterior aspect of the stomach were eligible., Interventions: An anterior gastric site for NOTES gastrotomy was chosen and transgastric NOTES access was independently established after laparoscopic abdominal exploration. Peritoneoscopy was then performed. The site of gastrotomy was closed as part of the intended laparoscopic procedure., Main Outcome Measures: The ability to visualize the abdominal and pelvic organs in all four quadrants was determined. Patients were evaluated postoperatively for complications., Results: Eight patients requiring 9 procedures were studied. Gastrotomy sites were classified as body (n = 3), lesser curvature (n = 3), greater curvature (n = 1), fundus (n = 1), and antrum (n = 1). Satisfactory navigation could only be performed to the right upper and both lower quadrants. The left upper quadrant, specifically the spleen, was adequately visualized in only 1 case (11%), where the gastrotomy site was at the greater curvature. One patient developed a surgical site infection requiring oral antibiotic therapy. The median postoperative stay was 2 days (range, 0-3 days)., Limitations: Small number of patients., Conclusion: NOTES peritoneoscopy with a gastrotomy on the anterior stomach permits adequate visualization of organs in the right upper and both lower quadrants. Visualization of the left upper quadrant and spleen is, however, limited unless access is gained on the greater curvature of the stomach. The accuracy of NOTES in identifying intra-abdominal pathology compared with laparoscopy remains to be determined., (Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: Most natural orifice transluminal endoscopic surgery (NOTES) procedures have been performed through the anterior stomach wall, based on the established safety of PEG placement. This approach does not afford mechanically efficient access to all anatomic areas of interest., Objective: To assess the utility of EUS in identifying safe alternate access sites for NOTES., Design: Nonsurvival animal experiment., Methods: Thirty-two EUS-guided access procedures were performed through the antrum, the posterior stomach wall, or the rectum of 12 pigs. Sixteen safe-access procedures (SAP) used sonographic guidance to achieve safe intraperitoneal access by avoiding extraluminal organs and vessels during the initial NOTES puncture. Sixteen unsafe-access procedures (UAP) evaluated potential complications of blind access by performing a standard NOTES puncture at sites adjacent to critical extraluminal structures identified by EUS. Access was achieved by using a similar technique for both SAPs and UAPs. Baseline and completion laparotomies were performed., Results: All 16 UAPs resulted in clinically relevant complications, such as liver laceration and iliac artery injury. In contrast, 13 SAPs were without complication. The 3 complications in the SAP group occurred with transrectal access and consisted of 2 minor complications and a small-bowel perforation., Conclusions: Blind NOTES access through the antrum, posterior stomach wall, and rectum could result in catastrophic complications. In contrast, EUS-guided access through these sites substantially reduced but did not completely eliminate this risk. EUS appears promising as an adjunct to NOTES access, particularly as more experience is gained in definitively excluding the presence of at-risk extraluminal structures.

Background: Efforts to develop improved endoscopic therapeutic methods for upper GI bleeding require an effective animal model., Objective: To develop a nonsurvival porcine model that simulates acute peptic ulcer bleeding., Design: Prospective animal (porcine) study., Setting: Animal laboratory., Interventions: A surgical seromyotomy was created along the external surface of the greater curvature of the stomach in anesthesized pigs. A submucosal plane was developed and the gastroepiploic bundle, in continuity, was placed adjacent to the mucosa, and the seromuscular tissues were re-approximated over the vascular bundle. By using EGD, a needle-knife with electrocautery was then used to incise the mucosal tissue overlying the vascular bundle. Standard endoscopic methods for bleeding control were then tested in this animal model., Main Outcome Measurements: To evaluate whether successful bleeding that simulates submucosal arterial bleeding from peptic ulcer disease could be achieved in a porcine animal model., Results: Successful simulation of active peptic ulcer bleeding was achieved with this nonsurvival porcine model in a total of 5 sequential pigs. Other porcine models for bleeding were tested and found to be unsatisfactory. Hemoclips and combination injection-thermal therapy were used to stop bleeding over Doppler-positive areas, with subsequent endoscopic nonimaging Doppler US probe examination of the ulcer bed revealing a negative Doppler signal., Limitations: This was an animal laboratory study. Further human studies would be ideal once any future endoscopic interventions are proven to be safe in animals., Conclusions: This active bleeding ulcer model can be used to develop future endoscopic therapies and for training purposes.

Background: Obtaining reliable closure of transvisceral defects currently limits natural orifice transluminal endoscopic surgery (NOTES). PEG tubes are potential means of managing NOTES gastrotomies., Objective: To determine the efficacy of PEG closure after NOTES., Design: An experimental animal study., Setting: A laboratory., Interventions: The pigs received gastric lavage with saline solution, chloramphenicol, or no lavage, and then underwent transgastric NOTES peritoneoscopy. Cultures were obtained by endoscopy during the surgery. A sterile foreign body was left in the peritoneal cavity. The gastrotomy was closed with a 20F PEG tube. The animals were observed for 14 days and underwent sterile laparotomy. Cultures of the foreign body and the peritoneal cavity were obtained., Main Outcome Measurements: Abscess rate, peritoneal quantitative cultures., Results: After 1 exclusion for anesthetic complications, 19 animals underwent NOTES; 18 (94.7%) survived the entire postoperative period. One animal died on postoperative day 2 after the PEG tube dislodged. At 14 days, 5 animals (27.8%) had intra-abdominal abscesses, 8 (44.4%) had positive peritoneal cultures, and 9 (50%) foreign bodies were contaminated on culture. Infectious complications were not altered by the type of gastric lavage or peritoneal bacterial inoculum introduced at the time of surgery., Limitation: An animal model., Conclusions: PEG closure of a NOTES gastrotomy is associated with subclinical intra-abdominal abscess formation and can result in death when the tube is dislodged during the early postoperative period. Preprocedural gastric lavage does not alter the intra-abdominal bacterial burden introduced at the time of surgery or subsequent infectious outcomes in the porcine model. These concerning findings necessitate additional studies to determine if porcine models are appropriate and applicable to human subjects in the NOTES setting.