Note: Only the anastomosis-relevant complications are listed here; for those specific to the procedure, see the corresponding article.
Anastomotic insufficiency
Common causes of suture insufficiency include: Non-economical skeletonization of the intestinal wall (perfusion disorder), sutures under tension (dehiscence), and intramural hematomas. Radiation, perfusion disorders, steroid and cytostatic therapy, catabolism, and shock states represent additional risk factors for intestinal suture.
Inadequate fibrin adhesion, infections, and anatomical or microbial peculiarities also promote anastomotic insufficiencies. Extraluminal additional safeguards for the intestinal suture include covering with peritoneum and omentum, with resorbable material such as PGS mesh, and coating the anastomosis with fibrin glue.
Infections and perfusion disorders are, according to clinical experience and animal experimental studies, the most essential causes of insufficiency of anastomoses. The infection-induced collagenase with increased collagen degradation leads to reduced strength of the anastomosis. A leakage can, if the intestinal contents enter the free abdominal cavity, lead to a life-threatening peritonitis . If the insufficiency is covered, an abscess develops, which can evolve into a intestinal fistula.
Abscess
Detritus, hematomas, foreign bodies, and the accumulation of lymph as well as their bacterial contamination are the origin of the perianastomotic abscess with risk of perforation. Deep colorectal or coloanal anastomoses are particularly endangered by such infections. The presence of feces promotes the infection and thus the insufficiency and its consequences.
Animal experimental and clinical statements report that lowered protein or plasma albumin and a significant preoperative weight loss (tumor cachexia!) represent risk factors for anastomotic healing.
Stenosis
All intestinal anastomoses tend to shrink. Rectal anastomoses, which are excluded from stool passage by an enterostomy, stenose more frequently. A stenosis is apparently prevented by the bougie effect of the stool passage.