Note: Only complications impacting the anastomosis will be discussed here; for complications specific to the procedure itself, see the corresponding Webop review.
Suture line failure
Common causes of suture line failure include: Liberal skeletonization of the intestinal wall (impaired perfusion), sutures under tension (dehiscence), and intramural hematoma. Irradiation, impaired perfusion, steroid and cytostatic therapy, catabolism, and states of shock are further risk factors in intestinal sutures.
Insufficient physiological fibrin adhesion, infections, and anatomical or microbial features also promote suture line failure. Additional extraluminal reinforcement in intestinal sutures includes coverage with peritoneum and omentum or with absorbable material such as PGS mesh and coating the anastomosis with fibrin glue.
According to clinical experience and animal studies, infections and impaired perfusion are the most significant causes of suture line failure. The infection-induced collagenase will increase collagen breakdown and decrease the strength of the anastomosis. Leakage may result in life-threatening peritonitis if the intestinal contents reach the free peritoneal cavity. If the suture line failure is walled off, an abscess will form, which may result in intestinal fistula.
Abscess
The outcome of perianastomotic abscess with the risk of rupture includes detritus, hematoma, foreign bodies, and lymph accumulation as well as its bacterial contamination. Deep colorectal and coloanal anastomoses are especially at risk of such infections. The presence of feces promotes infection and thus suture line failure and its sequelae.
Animal studies and clinical evidence indicate that decreased protein and plasma albumin and significant preoperative weight loss (tumor cachexia!) are risk factors in anastomotic healing.
Stenosis:
All intestinal anastomoses tend to shrink. Stenosis is especially more common in rectal anastomosis with proximal enterostomy protecting against fecal passage. The bougienage effect of fecal transit apparently prevents stenosis.