BETTER PRESERVATION OF IMMUNE FUNCTION AFTER LAPAROSCOPIC-ASSISTED VSOPEN BOWEL RESECTION IN A MURINE MODEL

PURPOSE: We evaluated cell-mediated immune function after laparoscopic -assisted and open bowel resection in rats by measuring delayed-type h ypersensitivity responses to keyhole limpet hemocyanin (KLH) and phyto hemagglutinin (PHA). METHODS: Male Sprague-Dawley rats (n = 120) were sensitized to 1 mg of KLH ten days before investigations. Rats were ch allenged preoperatively, immediately postoperatively, and on postopera tive day (POD) 2 with an intradermal injection of 0.3 mg of KLH and 0. 2 mg of PHA (at different sites). Averages of two measures of perpendi cular diameters (taken 24 and 48 hours postchallenge) were used to cal culate the area of induration using the formula for the area of an ell ipse, A = (D-1/2 X D-2/2) X pi. Anesthesia control animals underwent n o procedure (n = 40). Open resection group underwent ligation and rese ction of the cecum (length = 2 cm) through a 7 cm midline incision (n = 40). In the laparoscopic-assisted resection group, under CO2 pneumop eritoneum (4-6 mmHg), the cecum was identified, dissected free, and ex teriorized through a 4 mm port. The cecum was then ligated and resecte d extracorporeally (n = 40). RESULTS: Preoperative responses to both K LH and PHA were the same in all three groups. Furthermore, within each group, postoperative responses were similar. When groups were compare d, the anesthesia group responses were significantly greater than the open resection group responses at all time points (P < 0.05 for all co mparisons). Laparoscopic-assisted resection group responses differed f rom control at only two of eight postoperative measures. Laparoscopic resection group responses were significantly greater than open resecti on group responses to challenge with both KLH and PHA on POD1 (P < 0.0 2, for both comparisons) and POD 4 (P < 0.05, for both comparisons). C ONCLUSIONS: Postoperative cell-mediated immune function is better pres erved after laparoscopic-assisted bowel resection than after open rese ction as assessed by skin antigen testing.