Laparoscopic vs conventional bowel resection in the rat

Abstract

Background: The role of laparoscopic surgery in the treatment of colorectal disease is still controversial. To assess the metabolic consequences of laparoscopic and open bowel surgery, we studied serum levels of insulin-like growth factor 1 (IGF-1), an anabolic and mitogeneic peptide, in rats.

Materials and methods: In experiment 1, the serum IGF-1 levels of 10 rats undergoing laparoscopic small bowel resections (group I) and 10 rats undergoing conventional small bowel resections (group II) were determined before surgery and on days 1, 2, and 7. Experiment 2 compared five rats that had CO₂ pneumoperitoneum (group III), five rats that underwent laparotomy (group IV), and five rats that received anesthesia only (group V). Differences in IGF-1 levels were tested with analysis of covariance.

Results: In experiment 1, preoperative IGF-1 levels were similar in groups I and II (87.9 ± 6.1 nmol/L versus 90.5 ± 8.1 nmol/L). One day after surgery IGF-1 was 54.6 ± 10.5 in group I versus 41.6 ± 8.3 in group II (p= 0.006). Two days after surgery, IGF-1 was 79.4 ± 9.2 in group I versus 59.0 ± 10.5 in group II (p < 0.001). Seven days after both types of surgery, IGF-1 levels had returned to almost normal levels. In experiment 2, no significant differences were found between the rats with CO₂ pneumoperitoneum (group III) and those with laparotomy only (group IV). Rats that had anaesthesia only showed a significant decrease in IGF-1 levels between days 0 and 1 (p < 0.018).

Conclusion: Our study indicates that laparoscopic bowel surgery is associated with a better postoperative anabolic state (i.e., less catabolism) than conventional surgery. This finding reflects a potential benefit of laparoscopy in bowel surgery.