Transgastric versus laparoendoscopic single-site peritoneoscopy in a rat model: Effects on motility, inflammation, and nociception

Background: Natural orifice translumenal endoscopic surgery (NOTES) and laparoendoscopic single-port surgery (LESS) are emerging approaches to abdominal surgery that have been advocated as potentially causing fewer physiologic derangements and less pain. This study aimed to compare these procedures in a novel rat model by assessing peritoneal inflammation, gastric motility, and nociception in response to peritoneoscopy performed via NOTES and LESS. Methods: Adult male rats underwent peritoneoscopy via either transgastric NOTES or LESS using the same type of endoscope and were allowed to recover for 2 to 4 h. Liquid gastric emptying was assessed using phenol red, and cytokine levels were analyzed in peritoneal washings. Thoracic spinal cord segments were stained for Finkel-Biskins-Jinkins osteosarcoma gene (FOS) to assess activation of nociceptive pathways. Results: The NOTES procedure significantly delayed both postsurgical recovery time compared with LESS (115 ± 25 vs. 82 ± 20 min, respectively; P = 0.04) and liquid gastric emptying (26.7 ± 11.1% vs. 57 ± 10.5%; P = 0.004). Several cytokines such as interleukin-1β (IL-1β), IL-6, monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1beta (MIP-1β) were significantly elevated in the NOTES group compared with the LESS group. However, the two groups did not differ significantly in spinal FOS activation. Conclusions: The NOTES approach is feasible in an experimental rat model, facilitating a scientific approach to hypothesis testing through specific methods and instruments. The transgastric NOTES approach in rats is associated with a worse physiologic outcome in terms of gastric motility and peritoneal inflammation but does not differ significantly from LESS in activation of pain pathways.