Urinary diversion is a surgical procedure that creates a new pathway for urine to exit the body. This becomes necessary when the normal flow of urine is blocked or when the bladder needs to be removed, such as in cases of bladder cancer or severe bladder dysfunction. The procedure reroutes urine from the kidneys, bypassing the bladder, to either an external opening (stoma) or an internal pouch created from a segment of the bowel. This re-routing allows the body to continue removing waste and excess fluid, preventing complications that could arise from urine buildup.
Immediate Post-Operative Complications
Immediately following urinary diversion surgery, patients may experience a range of complications within the first few days or weeks. Bleeding is a concern, potentially requiring further intervention. Surgical site infections or urinary tract infections (UTIs) are common early issues.
Leakage of urine from the surgical connections can occur in about 2-5.5% of patients. Temporary issues with bowel function, such as a post-operative ileus (a temporary slowdown or halt of bowel movement), are frequently encountered. These immediate complications are typically managed in the hospital setting with close monitoring.
Stoma and Local Complications
For patients with an incontinent urinary diversion, where urine continuously drains through an opening on the abdomen called a stoma, several complications can arise over time. Stoma stenosis, or narrowing of the stoma, can impede urine flow and may require a revision procedure. Stoma retraction, where the stoma pulls inward towards the abdominal wall, or prolapse, where it protrudes outwards, are also potential issues that can make appliance management difficult.
A parastomal hernia, a bulge near the stoma where abdominal contents push through the muscle wall, is another common long-term complication, reported in up to 30% of patients with an ileal conduit. Skin irritation or breakdown around the stoma is a frequent problem, often caused by urine leakage or improper appliance fit, leading to discomfort and potential infection. Maintaining a proper seal for the collection appliance is important to prevent skin issues and ensure continuous drainage.
Urinary Tract and Kidney Complications
Complications affecting the upper urinary tract, including the ureters and kidneys, are long-term concerns following urinary diversion. Recurrent urinary tract infections (UTIs) are common, and these can sometimes ascend to the kidneys, leading to pyelonephritis. Up to 17% of patients with conduits may experience acute pyelonephritis, which can result in kidney function deterioration, especially when certain bacteria like Proteus or Pseudomonas are involved.
Obstruction of the ureters can occur at the point where they connect to the diverted bowel segment, leading to hydronephrosis, where urine backs up and causes the kidney to swell. This obstruction can be caused by scar tissue or strictures, and it may impact kidney function over time. Kidney stone formation is also more likely in individuals with urinary diversions due to changes in urine composition and potential urine stasis within the new pathway. Long-term, these issues can contribute to a decline in overall kidney function.
Metabolic and Systemic Complications
When a segment of the bowel is used for urinary diversion, the body’s chemistry can be affected, leading to metabolic and systemic complications. The bowel segment continues to have some absorptive and secretory properties when exposed to urine. This can result in hyperchloremic metabolic acidosis, where the body’s pH balance shifts towards acidity due to the absorption of chloride and excretion of bicarbonate. While chronic metabolic acidosis can exist in over 70% of patients, severe cases are less common, occurring in about 1%.
Electrolyte imbalances, such as hyperchloremia, can accompany metabolic acidosis. Malabsorption of nutrients, particularly vitamin B12, can occur if a significant portion of the ileum is used for the diversion, as this part of the small intestine is responsible for B12 absorption. This deficiency can lead to neurological and hematological issues over time. Additionally, chronic acidosis can lead to demineralization of bones as the body uses bone minerals like calcium to buffer the acidic environment, potentially contributing to conditions like osteomalacia or osteoporosis.