Risk factors for anastomotic fistula after total mesorectal excision: A monocentric retrospective study of 78 patients

Anastomotic fistulas remain one of the most feared complications following rectal surgery, particularly after Total Mesorectal Excision (TME). They compromise prognosis, prolong hospitalization, and increase costs due to the additional interventions they necessitate. To identify predictive factors for the occurrence of anastomotic fistulas, with the goal of personalizing and optimizing surgical management—particularly to guide decisions regarding the use of defunctioning stomas. We conducted a retrospective observational study on 78 patients who underwent TME with low rectal anastomosis for rectal adenocarcinoma at Hassan II University Hospital in Oujda, between December 2017 and May 2024. Of the 78 patients, 21 developed anastomotic fistulas, yielding an incidence rate of 26.9%. Late-onset cases were predominant (16 cases, 76.19 %) compared to early-onset cases (five cases, 23.81%). In univariate analysis, diabetes (p = 0.002), intraoperative incidents (p = 0.014) - particularly blood loss exceeding 150 cc (p = 0.001 ) - and smoking (p = 0.005) were significant risk factors for fistula development. In multivariate analysis, diabetes (OR = 10.87; p = 0.003) and intraoperative blood loss >150 ml (OR = 7.38; p = 0.030) emerged as independent predictors of fistula development. Active smoking showed a borderline association (OR = 6.46; p = 0.056), suggesting a potential but not statistically confirmed impact on anastomotic fistula. These findings are consistent with the existing literature. In contrast, other factors commonly reported in the literature, such as male sex (p = 0.530), ASA score (p = 0.612), anemia (p = 0.324), and preoperative (p = 0.781) and postoperative albumin levels (p = 0.119), did not show a significant association in our study. While the identified risk factors are relevant, they alone are insufficient to warrant major modifications in our surgical strategy, particularly regarding the decision to perform a defunctioning stoma. Further studies are necessary to validate these findings. • Anastomotic Fistulas remains among the most feared complications after rectal surgery, particularly following Total Mesorectal Excision (TME). • We conducted a retrospective observational study on 78 patients who underwent TME with low rectal anastomosis for rectal adenocarcinoma • 21 has developed anastomotic fistulas, resulting in an incidence rate of 26.9%, with a predominance of late-onset cases (16 cases, 76.19%) over early-onset cases (5 cases, 23.81%). • Our analysis revealed that diabetes (p=0.0002), intraoperative incident ( p=0,02) blood loss exceeding 150 cc (p=0.003), and smoking (p=0.005), duration of surgery were significant risk factors for fistulas • while the identified risk factors are relevant, they alone are not sufficient to justify significant modifications in our surgical strategy, particularly concerning the decision for defunctioning stoma, Further studies are needed to confirm our results.