794 Most studies addressing the problem of anastomotic leakage focus on the urgency of the operation. However, few studies report on the time of surgery in relationship to leakage rate. Higher leakage rates at night may be caused by a decreased technical and/or non-technical performance of the entire operating team. Given the current focus of society on medical errors and its prevention, more research should be done on this aspect of colorectal surgery. Prophylactic drainage (PD) appeared to be associated with anastomotic leakage, suggesting that it is a risk factor. However, statistical analysis shows that significantly more drains are placed after LAR (54% of all drains; p = 0,001) and that the duration of surgery on average is 70 min longer in the group that received a drain (219 min) than in the group without (148 min; p = 0,001). The latter is most likely caused by difficulty of operation and adverse events occurring during operation. This shows that the significant association between drainage and anastomotic leakage reflects the prophylactic drain-policy in our hospital. Additionally, since no significant differences in leakage rates between groups with and without drainage were reported in literature [11], PD cannot be considered as a risk factor for anastomotic leakage. Patient outcome Mortality rate due to leakage was 14.1%, which is comparable to mortality rates reported in literature [4, 29]. The aforementioned 33-day increase in mean hospital stay in case of anastomotic leakage was to be expected and is indicative for the enormous increase in costs that is accompanied by this complication. Concerning the postoperative complications, abdominal wound dehiscence (AWD) occurred significantly more often in patients with anastomotic leakage. In literature, several factors associated with abdominal wound dehis- cence, being advanced age, obesity, diabetes mellitus, and steroid use [36], are reported. In this population BMI (p = 0.06), presence of diabetes mellitus (p = 0.99) and use of steroids (p = 0.07) were not associated with AWD. The average age of surgery in the group without AWD was 57 years and in the group with AWD 67 years (p = 0.010). However, since age is not a factor associated with anastomotic leakage this finding cannot explain the correlation between AWD and leakage. Another possible explanation may be found in connective tissue disorders. To date, a substantial body of evidence exists correlating aortic aneurysms to incisional hernia, both caused by connective tissue disorders [37]. In addition, Stumpf et al. have shown colorectal anastomotic leakage is associated with disturbances of the extracellular matrix [38]. These findings suggest that a patient population exists that has a higher risk for developing aortic aneurysms, hernia and Int J Colorectal Dis (2009) 24:789–795 anastomotic leakage. 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