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BACKGROUND: Leak-resistant closure of transluminal access is a major challenge facing natural orifice transluminal endoscopic surgery (NOTES). OBJECTIVE: To evaluate a hydrogen (H(2))-based leak test for assessment of transluminal-access closure integrity after NOTES procedures. SETTING: Nine acute porcine experiments. DESIGN AND INTERVENTION: After gastric-wall puncture and balloon dilation, peritoneoscopy was performed, followed by transmural closure of the gastric opening. The animals were randomly assigned to complete or incomplete closure groups. The H(2) leak test was performed by using 1000 mL of 4% H(2) gas mixture and the Hydrogen Leak Detector H2000+. The animals were then euthanized for a methylene blue (MB) test of gastric closure integrity. MAIN OUTCOME MEASUREMENT: Intraperitoneal H(2) concentration after gastric insufflation with H(2). RESULTS: The H(2) leak test was quick and easy. Intraperitoneal H(2) concentrations in parts per million in both groups were similar at baseline (mean +/- SD, 0.18 +/- 0.29 parts per million [ppm] vs 0.22 +/- 0.35 ppm, P = .97) and after balloon dilation (414.8 +/- 198.5 ppm vs 601.3 +/- 116.1 ppm, P > .99). Postclosure intraperitoneal H(2) concentrations dropped to 0.01 +/- 0.77 ppm in the complete-closure group, similar (P = .81) to matched-pairs preopening levels and significantly lower than in the incomplete-closure group (162.0 +/- 83.0 ppm, P < .02). On necropsy, the MB test was negative in all 5 animals of the complete-closure group and positive in all 4 animals of the incomplete-closure group. A cutoff of 25 ppm in intraperitoneal H(2) concentration after closure gave 100% sensitivity, specificity, and positive and negative predictive values for MB leakage. LIMITATIONS: Nonsurvival animal experiments. CONCLUSIONS: The H(2) leak test is highly accurate for detection of leakage after NOTES procedures and could become a substitute for currently used MB leak tests. [ABSTRACT FROM AUTHOR]

BACKGROUND: Transluminal access site closure remains a major challenge in natural orifice transluminal endoscopic surgery (NOTES). OBJECTIVE: Our purpose was to develop in vivo leak tests for evaluation of the integrity of transgastric access closure. SETTINGS: Survival experiments on 12 50-kg pigs. DESIGN AND INTERVENTIONS: After a standardized transgastric approach to the peritoneal cavity and peritoneoscopy, the gastric wall incision was closed with T-bars (Wilson-Cook Medical, Winston-Salem, NC) deployed on both sides of the incision and then cinched together. Gastrotomy closure was assessed with air and fluid leak tests. The animals were observed for 1 week and then underwent endoscopic evaluation and necropsy. MAIN OUTCOME MEASUREMENTS: (1) Leak-proof closure of the gastric wall incision. (2) Gastric incision healing 1 week after the procedure. RESULTS: The mean intraperitoneal pressure increased 10.7 +/- 3.7 mm Hg during gastric insufflation when the air leak test was performed before closure compared with 0.9 +/- 0.8 mm Hg after transmural closure of the transgastric access site with T-bars (P < .001). Fluid leak tests demonstrated no leakage of liquid contrast from the stomach into the peritoneal cavity after closure. Necropsy in 1 week confirmed completeness of the gastric closure in all animals with full-thickness healing and no spillage of the gastric contents into the peritoneal cavity. LIMITATIONS: Leak tests were only evaluated on an animal model. CONCLUSIONS: Fluid and air leak tests are simple techniques to evaluate in vivo the adequacy of the transluminal access site closure after NOTES procedures. Leak-proof gastric closure resulted in adequate tissue approximation and full-thickness healing of the gastric wall incision. [ABSTRACT FROM AUTHOR]

Introduction: Lasers 2-microm in wavelength offer efficient tissue cutting with limited thermal damage in biological tissue., Objective: To evaluate the dissection capabilities of a 2-microm continuous-wave laser for NOTES procedures., Methods and Procedures: We conducted 18 acute animal experiments. Group 1 (three animals): transcolonic access to the peritoneal cavity (15-W transcolonic laser puncture, balloon dilation over the laser probe). Group 2 (six animals): transcolonic access with needle-knife puncture and balloon dilation. Group 3 (three animals): transgastric access to the peritoneal cavity (similar technique as group 1) followed by laser-assisted dissection of the kidney. In one animal of group 3, a therapeutic target (hematoma) was created by percutaneous puncture of the kidney. Group 4 (six animals): transgastric access (similar to the technique of group 2)., Results: Translumenal access to the peritoneal cavity was achieved in 2-3 min in group 1 (significantly shorter than with the needle-knife-assisted technique, 4-5 min, p=0.02) and in 7-10 min in group 3 (compared to 6-17 min in group 4, p=0.88). In group 3, laser dissection of the parietal peritoneum and of perinephric connective tissue allowed access to the retroperitoneum with complete removal of a blood collection in the animal with puncture trauma. Laser dissection demonstrated good maneuverability, clean and rapid cutting, and excellent hemostasis. Peritoneoscopy and necropsy showed no damage of targeted tissue and surrounding organs., Conclusions: The 2-microm continuous-wave laser system showed promising capabilities for highly precise and safe dissection during NOTES procedures.

Background: Closure of the transgastric access to the peritoneal cavity is a critical step in natural orifice transluminal endoscopic surgery (NOTES)., Objective: To perform a direct comparison of the histological healing post clips and threaded tags (T-tags) closure after transgastric NOTES procedures., Design and Intervention: Twelve survival porcine experiments. After standardized endoscopic gastric wall puncture, balloon-dilation, and transgastric peritoneoscopy, closure of the gastric wall was performed with either clips or T-tags. Necropsy at 14 days was performed for histological evaluation of 2-mm interval transversal cross sections of the gastrotomy site., Main Outcome Measurements: Histological healing of the gastric wall opening., Results: Endoscopic closure of the gastrotomy was successfully achieved in all 12 animals, followed by an uneventful 2-week clinical follow-up. Transmural healing was seen in 3 (75%) animals after clip closure compared with only 1 (12.5%) in the group with T-tag closure (P = .06). Gastric wall muscular bridging was observed in 4 (100%) animals with clip closure compared with only 1 (12.5%) in the group with T-tag closure (P = .01)., Limitations: Animal model with short-term follow-up., Conclusions: Endoscopic clip closure results in a layer-to-layer transmural healing of the gastric wall. In contrast, T-tag gastric wall plication impairs gastric layer bridging. These findings might guide the future design of new endoscopic devices and techniques for gastrotomy closure after NOTES procedures., (Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: Currently reported natural orifice transluminal endoscopic surgery (NOTES) procedures in animals have been done in heterogeneous milieus ranging from nonsterile to sterile procedures, with mixed results, including no infection in those performed in nonsterile settings., Objective: To establish the potential frequency of infection during NOTES, comparing sterile to nonsterile approaches., Setting: Survival experiments on sixteen 50-kg pigs., Design and Interventions: From pilot data (100% infection frequency after nonsterile procedures), sample size (8 animals in each group) was calculated by using a power of 95% and an alpha risk of 0.05. The animals were randomly assigned to two groups: In the transgastric peritoneoscopy study group, liver and ovarian biopsies were performed with sterile overtubes, endoscopes, and accessories and the use of preoperative intravenous antibiotics and antiseptic gastric lavage. In the nonsterile (control) group, the same procedures were performed with nonsterile endoscopes and accessories without the use of gastric lavage and preoperative antibiotics. Complete transmural closure of the transgastric access site was made in all animals. After a 1-week survival time, all animals were killed for necropsy, which included Gram staining and peritoneal cultures., Main Outcome Measurements: Intraperitoneal infection on necropsy., Results: All necropsies revealed intraperitoneal infection (abscesses, fibrinopurulent exudates, and adhesions) in the control group (frequency of infection 100%). Peritoneal bacterial culture grew various aerobic and anaerobic organisms. No gross or bacteriological evidence of infection was seen in the sterile group (frequency of infection 0%, P value = <.0002)., Limitations: Animal experiments., Conclusion: Nonsterile conditions invariably lead to intraperitoneal infection. Aseptic techniques during NOTES can prevent intra-abdominal infection. Future studies will determine which infection prevention steps are mandatory and which can be omitted during NOTES procedures., (Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.)

Background: We have previously reported the feasibility of diagnostic and therapeutic peritoneoscopy including liver biopsy, gastrojejunostomy, and tubal ligation by an oral transgastric approach. We present results of per-oral transgastric splenectomy in a porcine model. The goal of this study was to determine the technical feasibility of per-oral transgastric splenectomy using a flexible endoscope., Methods: We performed acute experiments on 50-kg pigs. All animals were fed liquids for 3 days prior to procedure. The procedures were performed under general anesthesia with endotracheal intubation. The flexible endoscope was passed per orally into the stomach and puncture of the gastric wall was performed with a needle knife. The puncture was extended to create a 1.5-cm incision using a pull-type sphincterotome, and a double-channel endoscope was advanced into the peritoneal cavity. The peritoneal cavity was insufflated with air through the endoscope. The spleen was visualized. The splenic vessels were ligated with endoscopic loops and clips, and then mesentery was dissected using electrocautery., Results: Endoscopic splenectomy was performed on six pigs. There were no complications during gastric incision and entrance into the peritoneal cavity. Visualization of the spleen and other intraperitoneal organs was very good. Ligation of the splenic vessels and mobilization of the spleen were achieved using commercially available devices and endoscopic accessories., Conclusions: Transgastric endoscopic splenectomy in a porcine model appears technically feasible. Additional long-term survival experiments are planned.

Background: We have previously reported the feasibility and safety of the peroral transgastric endoscopic approach for diagnostic peritoneoscopy, liver biopsy, and gastrojejunostomy with long-term survival in a porcine model. This approach eliminates incisions of the abdominal wall, providing a less invasive alternative to diagnostic and therapeutic laparoscopy. We now report successful performance of peroral endoscopic transgastric ligation of Fallopian tubes with long-term survival in a porcine model., Methods: Six female 50-kg pigs had general anesthesia and irrigation of the stomach with an antibiotic solution. Gastric puncture was performed with needleknife electrocautery followed by balloon dilatation of the tract with 20-mm TTS dilating balloon (Microvasive). A standard upper endoscope that underwent high-level disinfection and gas sterilzation was advanced into the peritoneal cavity through a sterile overtube. Both Fallopian tubes were identified and one was ligated using Olympus Endoloops. The other patent tube served as a control. Tubal patency was evaluated by hysterosalpingogram before and after ligation. After a follow-up period of 2-3 weeks, the pigs were sacrificed for postmortem examination., Results: The Fallopian tubes were easily accessed, identified and ligated in all 6 pigs. In each pig, fluoroscopy confirmed complete obstruction of the ligated tube with preserved patency of the other tube. All pigs survived well and ate heartily without any ill-effects. Postmortem examination did not reveal any peritonitis or intra-abdominal adhesions. The Endoloops were in place with complete obstruction of the ligated tubes and patency of the controls. Histopathologic examination of the tubes showed chronic inflammatory infiltrates without abscesses., Conclusions: The peroral endoscopic transgastric approach to ligation of the Fallopian tubes with long-term survival is technically feasible and safe in a porcine model. The endoscopic transgastric approach to the peritoneal cavity has potential for a wide array of diagnostic and therapeutic procedures.