PubMed2003
BACKGROUND: Animal studies have documented significantly better preserved postoperative cell-mediated immune function, as measured by serial delayed-type hypersensitivity (DTH) challenges, after laparoscopic-assisted than after open bowel resection. Similarly, in humans, the DTH responses after open cholecystectomy have been shown to be significantly smaller than preoperative responses; whereas after laparoscopic cholecystectomy, no significant change in DTH response has been noted. The purpose of this study was to assess cell-mediated immune function via serial DTH skin testing in patients undergoing laparoscopic or open colectomy. METHODS: A total of 35 subjects underwent either laparoscopic (n = 18) or open colectomy (n = 17) in this prospective but not randomized study. Only patients who were judged to be immunoresponsive by virtue of having responded successfully to a preoperative DTH challenge were eligible for entry in the study. DTH challenges were carried out at three time points in all patients: preoperatively, immediately following surgery, and on the third postoperative day (POD 3). Responses were measured 48 h after each challenge and the area of induration calculated. There were no significant differences between the laparoscopic (LC) and open (OC) colorectal resection groups in regard to demographics, indications for surgery, or type of resection carried out. The percentage of patients transfused was similar in both groups (17%, LC; 12% OC; p = NS). In the LC group, all cases were completed without conversion using minimally invasive methods. There were no perioperative deaths, and the rate of postoperative complications was similar in both groups. The preoperative and postoperative DTH results were analyzed and compared within each surgical group using several methods. RESULTS: In regards to the OC group results, the median sum-total DTH responses for the day of surgery challenges (0.44 +/- 69 cm2) and the POD 3 challenges (0.72 +/- 3.37 cm2) were significantly smaller than the preoperative results (3.61 +/- 3.83 cm2, p <0.0005 vs op day and p <0.0003 vs POD 3 results). When the LC group results were similarly analyzed, no significant difference in DTH response was noted between the pre- and the postoperative challenge results. Additionally, when the median percent change from baseline was calculated and considered for the OC group's DTH results, both postoperative challenge time points demonstrated significantly decreased responses when compared to their preoperative results (vs day of surgery, p <0.007; vs POD 3, p <0.006). Similar analysis of the LC group's results yielded nonsignificant differences between the pre- and postoperative responses. Lastly, when the LC and the OC groups median percent change from baseline results were directly compared for each of the postoperative challenges, a significant difference was noted for the POD 0 challenge (LC, -21%; OC 88%; p <0.004) but not for the POD 3 challenge. CONCLUSIONS: The postoperative DTH responses of the open surgery patients were significantly smaller than their preoperative responses. This was not the case for the laparoscopic group (a combination of fully laparoscopic and laparoscopic-assisted resections). When the open and laparoscopic groups results are directly compared, regarding the results of the day of surgery DTH challenges, the LC groups median percent change from baseline was significantly less than that observed in the OC group. These results imply that open colorectal resection is associated with a significant suppression of cell-mediated immune response postoperatively, whereas in this study laparoscopic colorectal resection was not. Further human studies are needed to verify these findings and to determine the clinical significance, if any, of this temporary difference in immune function following colon resection.