EVALUATION OF OPERATIVE STRESS AND PERITONEAL MACROPHAGE FUNCTION IN MINIMALLY INVASIVE OPERATIONS

BACKGROUND: Laparoscopic operative procedures have decreased postopera tive pain and the length of hospitalization. In addition, evidence sup ports a physiologic benefit from laparoscopic surgery, By analyzing se veral parameters of peritoneal macrophage function, we report a compar ison of the magnitude of postoperative stress between two types of min imally invasive access techniques contrasted with an open laparotomy, in a murine model, STUDY DESIGN Immature male A/J mice were exposed to pneumoperitoneum using carbon dioxide, gasless suspension, or laparot omy. Peritoneal macrophages were then harvested, and the number and vi ability of the macrophages from each group of mice were compared. Last , as a marker of postoperative stress, the in vitro production of nitr ic oxide and tumor necrosis factor alpha by these macrophages was dete rmined. RESULTS: The number of peritoneal macrophages and the viabilit y of the macrophages in the laparotomy group were significantly decrea sed 4 hours after operation compared with the minimally invasive and c ontrol groups, In addition, macrophage production of tumor necrosis fa ctor alpha and nitric oxide, two markers of macrophage stress, 24 hour s after operation was significantly increased in the laparotomy group compared with animals serving as controls, Gasless suspension and pneu moperitoneum decreased the number of macrophages to a lesser degree th an did open laparotomy and did not affect macrophage viability, Moreov er, gasless suspension and pneumoperitoneum did not lead to an increas e in tumor necrosis factor alpha or nitric oxide production by periton eal macrophages. CONCLUSIONS: Postoperative stress, assessed by a decr ease in macrophage viability and an-increase in cytotoxic cytokine pro duction, is maximized after laparotomy compared with stress in murine hosts that underwent minimally invasive treatment. These data provide basic scientific evidence for the possible physiologic benefit of mini mally invasive techniques.