Peritoneal inflammatory response of natural orifice translumenal endoscopic surgery (NOTES) versus laparoscopy with carbon dioxide and air pneumoperitoneum

The immunologic and physiologic effects of natural orifice translumenal endoscopic surgery (NOTES) versus traditional surgical approaches are poorly understood. Previous investigations have shown that NOTES and laparoscopy share similar inflammatory cytokine profiles except for a possible late-phase tissue necrosis factor-alpha (TNF-alpha) depression with NOTES. The local peritoneal reaction and immunomodulatory influence of pneumoperitoneum agents in NOTES also are not known and may play an important role in altering the physiologic insult induced by NOTES. In this study, 51 animals were divided into four study groups, which respectively underwent abdominal exploration via transgastric NOTES using room air (AIR) or carbon dioxide (CO2) or via laparoscopy (LX) using AIR or CO2 for pneumoperitoneum. Laparotomy and sham surgeries were additionally performed as control conditions. Measurements of TNF-alpha, interleukin-1 beta (IL-1 beta), and IL-6 were performed for peritoneal fluid collected after 0, 2, 4, and 6 h and on postoperative days (PODs) 1, 2, and 7. Of the 45 animals assessed, 6 were excluded because of technical operative complications. The findings showed that LX-CO2 generated the most pronounced response with all three inflammatory markers. However, no significant differences were detected between LX-CO2 and either NOTES group at these peak points. No differences were encountered between NOTES-CO2 and NOTES-AIR. Subgroup comparisons showed significantly higher levels of TNF-alpha and IL-6 with NOTES-CO2 than with LX-AIR on POD 1 (p = 0.022) and POD 2 (p = 0.002). The LX-CO2 subgroup had significantly higher levels of TNF-alpha than the LX-AIR subgroup at 4 h (p = 0.013) and on POD 1 (p = 0.021). No late-phase TNF-alpha depression occurred in the NOTES animals. The local inflammatory reaction to NOTES was similar to that with traditional laparoscopy, and the previously described late-phase systemic TNF-alpha depression in serum was not reproduced. At the peritoneal level, NOTES is no more physiologically stressful than laparoscopy. Furthermore, regardless of which gas was used, the role of the pneumoperitoneum agent did not affect the cytokine profile after NOTES, suggesting that air pneumoperitoneum is adequate for NOTES.