Colorectal Anastomotic Leakage: A New Experimental Model

Background

Anastomotic leakage is the major complication after colorectal surgery. To date, animal experiments concerning colorectal anastomosis focus on anastomotic healing instead of anastomotic leakage. This study aims to develop a new experimental model for colorectal anastomotic leakage.

Methods

A control group, receiving an anastomosis with 12 interrupted sutures, was compared to a group receiving an anastomosis with 6 interrupted sutures. When the leakage rate was observed to be too low, the number of sutures was decreased stepwise, to 5 or less. Each group contained 9 “C57Bl6–mice”. After 7 d the Anastomotic Bursting Pressure (ABP) was determined.

Results

In the first experiment, one mouse (11.1%) in the case group and none in the control group developed leakage. Average ABP was 152,2 mmHg in the control group and 138,8 mmHg in the case group (P=0,111). In the second experiment, case group receiving an anastomosis with 5 sutures, 4 mice (44.4%) in the case group developed leakage. This experiment was repeated twice resulting in leakage rates of 33.3% and 44.4%. The average overall ABP in the case group was 142,7 mmHg vs. 179,9 mmHg (P=0,022) in the control group. The mice without leakage showed a stabilization of average weight loss around day 2 and 3 and a decrease afterwards. The mice with leakage showed a decrease only after day 5. The difference in wellness-scores between the groups with- and without leakage was 2 points, increasing during follow-up.

Conclusions

The model of anastomotic leakage caused by creating an anastomosis with 5 interrupted sutures is feasible. Weight loss and wellness-scores are good predictors of leakage.

Key Words: colorectal anastomotic leakage, experimental animal model, anastomotic healing, anastomosis, C57bl6