Background: The immunologic and physiologic effects of NOTES are poorly understood when compared to traditional surgical approaches. Previous experimental models have shown NOTES and laparoscopy share similar acute-phase systemic inflammatory cytokine profiles, except for a possible late phase TNF-a depression in NOTES. The local immunologic peritoneal reaction and immunomodulatory influence of pneumoperitoneum agents are also not known in NOTES and may play an important role in altering the physiologic insult induced by NOTES.
Methods: Fifty-one animals were divided into 4 study groups which underwent abdominal exploration via transgastric NOTES with air or carbon dioxide (CO2) or laparoscopy (LP) with air or CO2. Laparotomy and sham surgeries were additionally performed as controls. TNF-a, IL-1b, and IL-6 were measured in peritoneal fluid collected at times 0, 2, 4, and 6 hours and on post-operative days (POD) 1, 2, and 7.
Results: 45 animals were assessed, with 6 excluded due to technical operative complications. LP (CO2) generated the most pronounced response with all 3 inflammatory markers. However, there were no significant differences detected between LP (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-a and IL-6 for NOTES (CO2) compared to LP (air) on POD 1 (p=0.022) and POD 2 (p=0.002), respectively. LP (CO2) had significantly higher levels of TNF-a compared to LP (air) at 4 hours (p=0.013) and POD 1 (p=0.021). There was no late-phase TNF-a depression in NOTES animals.
Conclusion: The local peritoneal inflammatory cytokine reaction to NOTES is similar to traditional laparoscopy, and previously described late-phase systemic TNF-a depression could not be reproduced at the peritoneal level. Regardless of which gas, the role of the pneumoperitoneum agent used in NOTES did not affect the cytokine profile when compared to the gold standard of CO2 laparoscopy. At the peritoneal level, NOTES is no more physiologically stressful locally than laparoscopy. From an immunologic perspective, CO2 pneumoperitoneum does not convey immunomodulatory effects in NOTES, and air pneumoperitoneum is adequate for NOTES procedures.
Session: Podium Presentation
Program Number: S121