Late phase TNF-alpha depression in natural orifice translumenal endoscopic surgery (NOTES) peritoneoscopy

BackgroundNatural orifice translumenal endoscopic surgery (NOTES) allows access to the peritoneal cavity without skin incisions. Contamination of the peritoneal cavity by enteric contents may render NOTES more physiologically and immunologically invasive than previously thought. Measurement of interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) is a validated method to quantify surgical stress. The physiologic and immunologic impact of NOTES is unknown.MethodsA total of 37 swine underwent abdominal exploration via transgastric NOTES peritoneoscopy, laparoscopy (LX), laparotomy (OPEN), or sham surgery (CONTROL) and were allowed to survive. TNF-α, IL-1β, and IL-6 plasma levels were determined at the start and completion of surgery, and at 1 hour, 2 days, and 14 days postoperatively.ResultsAt surgical completion, OPEN animals demonstrated higher TNF-α levels than all groups. TNF-α levels were similar for all groups at 1 hour and 2 days. NOTES animals had significantly reduced plasma levels of TNF-α than all other groups on postoperative days 7 and 14. Controlling for baseline cytokine variability, analysis was repeated using normalized data, which confirmed significantly reduced TNF-α levels for NOTES compared with all groups at 14 days. Subset analysis excluding LX and OPEN complications revealed lower NOTES TNF-α levels at 7 and 14 days compared with all groups. IL-1β and IL-6 levels were undetectable in 66.8% and 70.5% of samples, respectively, without significant trends.ConclusionsDiagnostic NOTES peritoneoscopy demonstrated similar levels of systemic proinflammatory cytokine TNF-α compared with diagnostic laparoscopy and exploratory laparotomy in the immediate postoperative period despite gross intraperitoneal contamination. None of the surgical groups, however, produced a measurable, consistent trend in IL-1β or IL-6. Consistently reduced levels of TNF-α in NOTES animals in the late postoperative period indicates an immunomodulatory effect of the NOTES surgical technique not present in laparoscopy or laparotomy.