Colorectal anastomotic leakage caused by insufficient suturing after partial colectomy: A new experimental model

Background: Colorectal anastomotic leakage (CAL) is the most important complication of colorectal surgery, accounting for one third of post-operative deaths. To prevent it, many interventions have been tested in animal models, mostly rats. However, few of these models have been validated. We aimed to develop a reproducible rat CAL model by creating an anastomosis with insufficient suturing after partial colectomy. Methods: To establish the number of sutures that would create an appropriate leakage rate for research (20%-50%), partial colectomy was performed in 60 Wistar rats using a 12-suture anastomosis in the control group and an anastomosis with insufficient suturing in the experimental group, starting with five sutures. Seven days later, the rats were examined for the occurrence and severity of CAL, the presence of adhesions, and anastomotic bursting pressure. When an acceptable leakage rate was achieved, the experimental and control studies were repeated twice to confirm the adequacy of the chosen technique. Results: On day 7, five-suture and 12-suture anastomoses had leakage rates of 50% vs. 30%, 44.4% vs. 20%, and 50% vs. 20%, respectively, in the various series. Overall, the five-suture group had a significantly higher CAL rate than did the 12-suture group (48.3% vs. 23.3%; p=0.045). It also had higher CAL severity and more adhesions (p for both<0.05). The bursting pressure of these anastomoses was significantly lower than that in the 12-suture group (116.8±58.9mm Hg vs. 150.4±50.3mm Hg; p=0.041). Conclusion: Anastomosis with five sutures after partial colectomy provides a suitable rat CAL model. Its future applications may help to improve the consistency of CAL studies.