Comprehensive Guide to Urinary Diversion Surgery: Techniques, Indications, and Outcomes

Urinary diversion (UD) is a surgical procedure performed when the normal urinary system is compromised or surgically altered. This could be due to bladder cancer, neurogenic bladder, severe trauma, congenital abnormalities, or chronic infections. The goal is to reroute urine flow from the kidneys to an alternate collection point, bypassing the bladder. Given the complexity of the procedure and its profound impact on the patient's quality of life, understanding the nuances of urinary diversion is essential for surgeons.

Indications for Urinary Diversion

1. Bladder Cancer

Bladder cancer, particularly muscle-invasive or high-grade non-muscle-invasive types, is the most common indication for urinary diversion. Following a radical cystectomy (removal of the bladder), patients need an alternative route for urine excretion.

2. Neurogenic Bladder

Conditions such as spinal cord injury, spina bifida, and multiple sclerosis can lead to neurogenic bladder, which may necessitate UD if conservative management fails. Urinary diversion can help reduce renal deterioration and urinary tract infections (UTIs) in these cases.

3. Congenital Abnormalities

Children born with conditions like bladder exstrophy or posterior urethral valves might require UD if reconstructive surgeries are not feasible.

4. Chronic Infections and Inflammation

Chronic conditions such as interstitial cystitis, recurrent UTIs, or severe radiation cystitis can lead to a contracted, dysfunctional bladder. In these scenarios, urinary diversion can offer symptomatic relief and prevent further complications.

5. Severe Trauma

Trauma to the bladder or urethra, especially in complex pelvic fractures, may lead to a non-functional bladder, necessitating diversion.

Preoperative Evaluation

The preoperative evaluation for urinary diversion is extensive, requiring a multidisciplinary approach involving urologists, anesthesiologists, and sometimes nephrologists and oncologists. Key elements of the preoperative workup include:

1. Patient’s General Health

Patients must be assessed for fitness to undergo major surgery. This includes evaluation of cardiovascular, respiratory, and renal function.

2. Renal Function

Given that UD can impact renal function, baseline renal function tests, including serum creatinine and glomerular filtration rate (GFR), are critical. Imaging studies like renal ultrasound and CT urogram are used to assess upper tract anatomy.

3. Psychological Evaluation

UD often involves a significant lifestyle change, particularly with continent diversions that require catheterization or with ostomies requiring external bags. A psychological assessment helps in determining the patient’s ability to cope with these changes.

4. Nutritional Status

Malnourished patients are at higher risk for surgical complications. Nutritional assessments, including albumin levels and body mass index (BMI), should be part of the preoperative evaluation.

5. Bowel Preparation

For continent diversions and neobladders that require intestinal segments, bowel preparation is crucial. This involves mechanical bowel preparation and antibiotic prophylaxis to reduce the risk of postoperative infections.

Contraindications for Urinary Diversion

Urinary diversion is contraindicated in the following scenarios:

1. Severe Comorbidities: Patients with significant cardiovascular or pulmonary disease may not tolerate the stress of major surgery.
2. Active Infection: An untreated UTI or systemic infection increases the risk of sepsis postoperatively.
3. Poor Renal Function: Patients with severe renal impairment may not be candidates for diversion, especially those requiring bowel segments, as this can lead to electrolyte imbalances.
4. Shortened Life Expectancy: In terminally ill patients, the risks of the procedure may outweigh the benefits.

Surgical Techniques and Steps

Urinary diversion can be broadly categorized into incontinent and continent diversions. The choice of technique depends on patient preference, health status, and the surgeon’s expertise.

1. Incontinent Diversions

A. Ileal Conduit

The ileal conduit is the most common type of incontinent diversion. After removing the bladder, a segment of the ileum (about 15-20 cm) is isolated and used to create a conduit. The ureters are implanted into this ileal segment, and one end of the conduit is brought out through the abdominal wall to form a stoma. Urine flows continuously into an external appliance (urostomy bag).

Steps:

1. Isolate a segment of the ileum, maintaining its blood supply.
2. Re-anastomose the remaining bowel.
3. Implant the ureters into the isolated segment.
4. Bring the conduit out to the skin to create a stoma.
5. Secure the stoma and attach an external urostomy bag.

B. Cutaneous Ureterostomy

In patients who are not candidates for an ileal conduit (due to poor bowel function), a cutaneous ureterostomy may be performed. Here, the ureters are directly attached to the skin, forming a stoma for urinary drainage. This technique is usually reserved for patients with limited life expectancy or those who cannot tolerate more complex procedures.

Steps:

1. Mobilize the ureters.
2. Bring each ureter to the skin, creating individual stomas.
3. Protect and secure the stomas with appropriate appliances.

2. Continent Diversions

A. Indiana Pouch

The Indiana pouch is a type of continent cutaneous urinary diversion where the right colon and terminal ileum are used to create a reservoir. The appendix or a tapered ileum is used as the catheterizable channel. Patients empty the pouch by inserting a catheter into the stoma.

Steps:

1. Isolate a segment of the ascending colon and terminal ileum.
2. Create a pouch by folding and suturing the bowel.
3. Taper the ileum to create a catheterizable channel.
4. Implant the ureters into the pouch.
5. Create a stoma for catheterization.

B. Neobladder

The orthotopic neobladder is a continent diversion where a new bladder is created using a segment of the bowel (typically ileum or ileocecal segment). The neobladder is attached to the urethra, allowing the patient to void normally. This option is ideal for patients who are motivated to maintain continence and who have intact urethral sphincters.

Steps:

1. Isolate a segment of the ileum.
2. Fold and suture the bowel to create a spherical reservoir.
3. Attach the ureters to the neobladder.
4. Anastomose the neobladder to the urethra.
5. Ensure that the patient can void voluntarily.

Postoperative Care

Postoperative care focuses on managing complications, promoting recovery, and preparing the patient for lifestyle adjustments.

1. Early Postoperative Care

• Pain Management: Adequate pain control is crucial, often managed with epidural analgesia or patient-controlled analgesia (PCA).
• Infection Prevention: Prophylactic antibiotics and careful monitoring of the surgical site and stomas reduce infection risks.
• Fluid and Electrolyte Balance: Bowel segments used in diversion absorb electrolytes, necessitating careful monitoring of fluid and electrolyte balance.
• Stoma Care: Patients with incontinent diversions require education on stoma care, including how to change the appliance and maintain skin integrity.

2. Long-Term Follow-Up

Patients with urinary diversions require lifelong follow-up to monitor renal function, stoma health, and for potential complications such as:

• Obstruction: Ureteral strictures or stomal stenosis can lead to obstruction and hydronephrosis.
• Infections: Recurrent UTIs are common, particularly in continent diversions requiring catheterization.
• Renal Function Decline: Long-term renal function should be monitored with regular serum creatinine tests and imaging studies.
• Metabolic Complications: The use of bowel segments in urinary diversion can lead to metabolic acidosis, vitamin B12 deficiency, and electrolyte imbalances.

Complications

Complications can occur early or late postoperatively. Some of the most common complications include:

1. Infections: UTIs, pyelonephritis, and surgical site infections are common.
2. Stoma-Related Issues: Stomal retraction, prolapse, or peristomal skin irritation can cause significant morbidity.
3. Obstruction: Ureteral strictures or stomal stenosis can lead to hydronephrosis and renal impairment.
4. Electrolyte Imbalances: Depending on the bowel segment used, patients may develop metabolic acidosis, hyperchloremia, or vitamin deficiencies.
5. Continence Issues: Patients with neobladders or continent diversions may experience incontinence or difficulty catheterizing.

Different Techniques and Their Pros and Cons

1. Ileal Conduit

• Pros: Simple, reliable, low complication rates.
• Cons: Requires an external appliance, risk of stomal complications.

2. Indiana Pouch

• Pros: No external appliance, better quality of life for motivated patients.
• Cons: Requires self-catheterization, risk of pouch complications.

3. Neobladder

• Pros: Allows for normal voiding, no external appliance.
• Cons: High complication rates, risk of incontinence or retention, complex surgery.