Stress response and well-being after open, laparoscopic, and NOTES transgastric uterine horn resection in a randomized porcine model.

BACKGROUND: NOTES is believed to induce less surgical trauma than open and laparoscopic surgery. The degree of surgical trauma can be assessed by measuring serum levels of acute-phase proteins such as CRP and TNF-α. We conducted a prospective randomized survival trial in which the inflammatory responses after laparoscopic, open, and NOTES transgastric uterine horn resection were compared. The aim of this study was to investigate whether NOTES procedures induce less inflammatory response. METHODS: Thirty pigs were randomized into three groups to undergo open, laparoscopic, or transgastric uterine horn resection. Weight, body temperature, and postoperative recovery were recorded and venous blood samples were taken for analysis of CRP and TNF-α at different time points. Analyses of CRP and TNF-α were performed using pig-specific ELISA assays. RESULTS: Procedure time was significantly longer for NOTES [median = 121 min (range = 94-155)] compared with that for open surgery [median = 22 min (14-27)] and laparoscopy [median = 37 min (20-45)] (p < 0.0001). There was a nonsignificant tendency for shorter recovery time for the NOTES animals. Twenty-seven animals survived for 4 weeks. One animal in each group was euthanized prior to 4 weeks. All animals gained weight during the 4-week period with no significant differences. Only animals in the NOTES group showed a significant weight gain during the first postoperative week (p = 0.007). On postoperative day (POD) 1, CRP was significantly lower in the NOTES group compared with the open and laparoscopic groups (mean = 0.72 ± 0.22, 0.98 ± 0.26, and 0.97 ± 0.20, respectively; p = 0.048). The CRP levels were normalized on day 14. Throughout the study there were no significant changes in TNF-α levels in the laparoscopic and NOTES groups. At POD 3 the open surgery group showed significantly higher TNF-α levels than the other groups (p = 0.036). CONCLUSIONS: Despite the longer operating time, the transgastric NOTES approach seems to be less traumatic than open or laparoscopic uterine horn resection in this porcine model.

A randomized trial comparing rates of abdominal contamination and postoperative infection among natural orifice transluminal endoscopic surgery, laparoscopic surgery, and open surgery in pigs.

BACKGROUND: Bacterial contamination of the abdominal cavity and infectious complications have been debated concerning transgastric natural orifice transluminal endoscopic surgery (NOTES) procedures. OBJECTIVE: The aim of this study was to compare bacterial contamination of the abdominal cavity and clinically relevant infections after open, laparoscopic, and transgastric NOTES procedures. DESIGN: Randomized survival study in a porcine model. SETTING: Animal laboratory at a university hospital. INTERVENTION: Thirty pigs were randomized to open, laparoscopic, or transgastric NOTES uterine horn resection under sterile conditions. Bacterial cultures were obtained from the pelvic area immediately at entry of the abdominal cavity and just before closure. The left uterine horn was dissected and ligated. The animals survived for 4 weeks. At necropsy, bacterial culture was obtained from the pelvic area. MAIN OUTCOME MEASUREMENTS: Perioperative: operation time and incision length, bacterial growth in abdominal samples. Postoperative: infections or complications, weight gain. Necropsy: signs of peritonitis or infection, abdominal bacterial growth. RESULTS: Procedure time was significantly longer for transgastric NOTES. At the start of the procedure, 4 of the NOTES animals showed positive cultures, but only 1 showed positive cultures at the end. No open surgery or laparoscopic surgery animals showed positive cultures at these time points. At necropsy, none of the animals in the NOTES group showed bacterial growth, whereas 4 open surgery animals and 3 laparoscopic surgery animals had positive cultures. Four of these animals (2 from each group) had concurrent wound infections. LIMITATIONS: Small sample size and lack of power calculation. CONCLUSION: This study indicates that clinically relevant infections are rare after transgastric NOTES procedures despite evidence of bacterial contamination and longer operating times.

Surgical Trauma Caused by Different Abdominal Access Routes-Comparison of Open Surgical, Laparoscopic, and NOTES Transgastric Techniques in a Porcine Model.

BACKGROUND: Investigations indicate that natural orifice translumenal endoscopic surgery (NOTES) procedures induce a less pronounced postoperative inflammatory response than open or laparoscopic surgery, inflicting less trauma. In NOTES procedures, no skin incision is performed. We compare the inflammatory response added by the type of incision by measuring C-reactive protein (CRP) and tumors necrosis factor-alfa (TNF-α). METHODS: Twenty-seven pigs were randomized to open surgical, laparoscopic, or transgastric NOTES abdominal access. After completion of the accesses, no surgery was performed. All accesses were left open for 40 minutes followed by closure, animals were survived for 7 days. Blood samples were drawn at the start of the accesses, at 20 and 40 minutes during the procedure, and at postoperative day (POD) 1, 3, and 7. Analyses of CRP and TNF-α were performed. RESULTS: CRP increased in all animals until POD1. This increase was greater in the open group (P = .006). No significant differences in CRP-levels were found at POD 1, 3, or 7. TNF-α showed a peak during the procedure, at 20 and 40 minutes, with normalization at POD1 for 1/3 of the open and laparoscopic animals, but not for the NOTES animals. Due to variations within the groups, no statistical difference was shown between them. At postmortem, 1/3 of the pigs in the laparoscopic and open groups had wound infections, while no NOTES animals showed infections. CONCLUSIONS: This study provides no statistically significant differences in inflammatory response after the different abdominal accesses. However, the lack of a TNF-α-peak in the NOTES group might indicate a less pronounced response, supporting the initial theories.

A new in vivo method for testing closures of gastric NOTES incisions using leak of the closure or gastric yield as endpoints.

BACKGROUND: We developed a non-survival in vivo model for testing of gastric natural orifice translumenal endoscopic surgery (NOTES) closures based on the gastric yield pressure. The aim of this study was to test our model comparing different endoscopic closure techniques with surgical closure of a NOTES gastric incision. METHODS: Laparotomy was performed in 30 pigs. One tube for air inflation and one manometry tube were inserted into the stomach via the pylorus, which was closed gas-tight, and the abdominal wall was closed. The stomach was inflated with air, and the gastroesophageal yield pressure was measured. A gastroscopy was performed, and a standard NOTES access was created followed by randomization to closure by surgical suturing, T-tags, Padlock-G over-the-scope (OTS)-clips, OVESCO OTS-clips, and traditional clips. All closures were tested twice with air insufflation. Gastric yield pressure or leak pressure of each closure was recorded. RESULTS: The mean baseline gastric yield pressure was 80.5 mm Hg. Post-closure yield pressure was 79.9 mm Hg. Leak test results after closure were as follows: surgery, 0/6 leaked; T-tags, 1/6 leaked before reaching yield pressure (56 mm Hg); Padlock-G, 2/5 leaked (71.5 mm Hg); OVESCO OTS-clips, 3/6 leaked (27.2 mm Hg); and traditional clips, 5/6 leaked (27.2 mm Hg). TAS T-tags and surgical closures leaked significantly less than the other groups (P=.01). Traditional clips and OVESCO OTS-clips leaked at significantly lower pressures than the other three groups (P=.007). CONCLUSION: This in vivo model using leak of the closure or the gastric yield pressure as endpoints for testing of the closure strength of a NOTES gastric access site seems to be reproducible. Our results support closure with T-tags and Padlock-G-clips over OVESCO OTS-clips and standard endoscopic clips.