Urinary Diversion — UroCompanion

Urinary diversion re-routes the upper urinary tract after cystectomy (or for a diseased/dysfunctional bladder) using a reconfigured segment of bowel. Options fall into three families: conduit (incontinent cutaneous), continent cutaneous, and orthotopic (neobladder) diversion. This page covers the intestinal segments and anastomoses common to all of them, then the orthotopic neobladder in detail.

Intestinal Segments and Urinary Diversion

Indications for Urinary Diversion after Cystectomy

A diseased bladder; dysfunctional bladder with persistent bleeding; obstructed ureters; poor compliance with upper-tract deterioration; inadequate storage with total urinary incontinence; and, before transplantation, a bladder that cannot adequately receive the transplant ureter.

Surgical Anatomy of Bowel Segments

Stomach — a vascular organ supplied primarily by three branches of the celiac trunk:

Left gastric artery — lesser curvature.
Hepatic artery — gives the right gastric artery (also the lesser curve) and the gastroduodenal artery (antrum and duodenum) before the latter gives the right gastroepiploic artery.
Splenic artery — gives the vasa brevia (short gastrics) supplying the fundus and cardia, and the left gastroepiploic artery.

The right and left gastroepiploic arteries anastomose along the greater curve and supply collateral flow; using the gastroepiploic vessels, a gastric pedicle can be mobilized as far as the pelvis. A fundal wedge should not include a significant portion of the antrum and should never extend to the pylorus or to the lesser curve.

Small bowel — ~22 feet long (range 15–30). Differences between ileum and jejunum:

Feature	Ileum	Jejunum
Position	More distal	More proximal
Diameter	Smaller	Larger
Arterial arcades	Multiple	Single
Arcade vessels	Smaller	Larger
Mesentery	Thicker	Thinner

The arcades are fed by the superior mesenteric artery. Experimentally up to 15 cm of small bowel can survive lateral to a straight vessel, but in general assume that >8 cm away from a straight vessel will not survive. In a prior-pelvic-radiation patient, avoid the two small-bowel segments most likely irradiated: the last 2 inches of terminal ileum, and the 5 feet of small bowel beginning ~6 feet from the ligament of Treitz.

Colon — cecum, ascending, transverse, descending, sigmoid, and rectum. The ascending colon is fixed to the right posterior abdominal wall to the hepatic flexure (hepatocolic ligament); the transverse colon lies free and is fixed at the splenic flexure (phrenocolic ligament) and attached to the stomach by the gastrocolic omentum; the descending colon is fixed to the left lateral wall; the sigmoid may or may not lie free. An omental flap should be based on the right gastroepiploic artery (usually larger caliber than the left).

Blood supply — superior mesenteric, inferior mesenteric, and internal iliac arteries (ileocolic, right/middle/left colic, sigmoid, and superior/middle/inferior hemorrhoidal arteries).
Weak points in the vascular supply (3): the sigmoid–superior hemorrhoidal junction (Sudeck's critical point), the midpoint between the middle and right colic arteries, and the midpoint between the middle and left colic arteries. Site an anastomosis to one side of these points.
Venous drainage — the inferior mesenteric vein drains into the splenic vein; the superior mesenteric vein joins the splenic vein to form the hepatic portal vein.

Bowel Preparation

Normal bowel flora comprises aerobes (most commonly Escherichia coli and Enterococcus faecalis) and anaerobes (most commonly Bacteroides and Clostridium). Bacterial concentration rises distally:

Segment	Organisms per gram of fecal content
Jejunum	10–10⁵
Distal ileum	10⁵–10⁷
Ascending colon	10⁶–10⁸
Descending colon	10¹⁰–10¹²

Solid feces can strain a fresh anastomosis and cause ischemia/perforation; fecal contamination drives peritonitis, intra-abdominal abscess, wound and anastomotic dehiscence, and systemic sepsis. Preparation is classified as mechanical vs antibiotic.

Mechanical (whole-gut irrigation) — reduces the amount of feces and total number of bacteria but not their concentration; done with polyethylene glycol (PEG)–electrolyte solution. A 2011 Cochrane review (Güenaga; 18 trials, 5,805 participants) found no difference in anastomotic leakage or wound infection — though many studies used perioperative IV antibiotics, likely crucial. No study has adequately assessed omitting mechanical prep in urologic reconstruction. Contraindications (5): obstructed bowel, unstable cardiovascular system, congestive heart failure, cirrhosis, severe CKD. Adverse events: hypokalemia (vigorous cleansing, even with electrolyte solutions, often lowers potassium — watch for muscle weakness with poor respiratory effort and a normal chest X-ray) and diarrhea.
Antibiotic — reduces bacterial concentration. Perioperative IV antibiotics appear to be the single most important means of preventing infectious complications and must be given before the operative event to be effective; a randomized colorectal trial found preoperative (oral) antibiotics alone did not reduce clinical infections. Cover anaerobes. Adverse events: diarrhea and pseudomembranous enterocolitis (treat with vancomycin or metronidazole and stop other antibiotics).

Selecting the Intestinal Segment

Ileum and colon are used most often. Jejunum is usually avoided because it may cause severe electrolyte imbalance. The same electrolyte abnormalities are possible with ileum or colon, but nutritional problems (vitamin B12 deficiency, bile-salt malabsorption) are less with colon than ileum as long as the ileocecal valve is left intact.

Conduit Diversions

Ileal conduit — the simplest conduit, with the fewest intraoperative and immediate postoperative complications. Contraindications (3): short bowel syndrome, inflammatory small bowel disease, and extensive prior pelvic irradiation affecting the ileum. Technique (condensed): a 10–15 cm segment is isolated ~10–15 cm from the ileocecal valve, keeping the mesenteric base wide and mesenteric windows modest (~5 cm) to prevent ischemia; bowel continuity is restored (ileoileostomy) and the mesenteric trap closed; the segment is flushed; the ureters are mobilized (the left ureter passed under the sigmoid mesentery) and the stented ureteroileal anastomoses performed; the conduit base is retroperitonealized in the right lower quadrant.

Colon conduit — common variants: transverse, sigmoid, and ileocecal.

Transverse colon — for prior extensive pelvic irradiation, or when an intestinal pyelostomy is needed.
Sigmoid — a good choice in pelvic exenteration patients who will already have a colostomy (no bowel anastomosis needed). Contraindications: internal iliac artery ligated with the rectum left in situ; extensive pelvic irradiation.
Ileocecal — provides a long ileal segment when long ureteral replacement is needed, plus colon for the stoma. Contraindications (3): inflammatory large bowel disease, disease of the segment considered, and severe chronic diarrhea.

Jejunal conduit — avoids irradiated bowel/ureter but may cause severe electrolyte imbalance; rarely used except when neither colon nor ileum is available.

Stomach conduit — rarely indicated; consider when other segments in a patient with limited intestine would cause serious nutritional problems. Advantages: electrolyte imbalance rare with normal renal function; less permeable to urinary solutes; net excretion (rather than absorption) of chloride and hydrogen ions — may help patients with pre-existing metabolic acidosis or renal dysfunction; no malabsorption (an option in short bowel syndrome); usually outside prior radiation fields; produces less mucus; acidic pH reduces bacterial colonization. Complications specific to stomach — early: gastric retention (atony/anastomotic edema), hemorrhage (usually anastomotic), hiccups (gastric distention), pancreatitis (intraoperative injury), gastroduodenal/gastroureteral leaks (occasionally fatal); late: dumping syndrome, steatorrhea, small-stomach syndrome, increased transit time, bilious vomiting, afferent-loop syndrome, hypoproteinemia, hematuria–dysuria syndrome (from excreted acid), severe metabolic alkalosis with respiratory distress (most likely with elevated gastrin), megaloblastic or iron-deficiency anemia, and rare severe ulcerative complications (consider long-term H2 or proton-pump inhibition).

Ileal vesicostomy — uses spatulated ileum and a generous transverse cystotomy to decompress the bladder for an abdominal appliance. Well suited to spinal-cord-injury or neurologically impaired patients, particularly those with detrusor–external sphincter dyssynergia.

Intestinal Anastomoses

Principles (6): adequate exposure; adequate blood supply; prevention of local enteric spillage; watertight serosal apposition without tension; sutures snug but not strangulating; and realignment of the two mesenteries.

Anastomoses may be sutured or stapled, with similar complication rates (leak/fistula ~2.8% stapled vs ~3% sutured). Theoretical benefits of stapling include better blood supply to the healing margin, less tissue manipulation, less edema, a wider lumen, and faster construction with shorter postoperative ileus. The TA stapler everts the suture line and closes in a "B" configuration that does not crush tissue (theoretically avoiding ischemia); most intestinal anastomoses use medium staples (closed height ~1.5 mm). Staples should not be used in bowel exposed to urine because of the risk of stone formation — use absorbable suture instead.

Complications — the most common cause of early postoperative morbidity/mortality in gut-incorporating urologic surgery relates to the bowel. Factors contributing to anastomotic breakdown: poor blood supply, local sepsis from fecal spillage, a drain on an intra-abdominal anastomosis, and an anastomosis in irradiated bowel (prior radiation markedly increases serious complications after cystectomy). Complications include fecal leak, sepsis, wound infection, abdominal abscess, hemorrhage, anastomotic stenosis, and bowel obstruction.

Bowel obstruction is most common when ileum is used; the most common cause is adhesions, followed by recurrent cancer.
Ogilvie syndrome (colonic pseudo-obstruction) — usually within the first 3 days in patients with multiple medical illnesses; cause unknown; presents with severe abdominal pain and a dilated cecum on radiograph.
Fistulas (fecal and urinary) and wound dehiscence may complicate the early period.
Complications of the isolated segment — strictures and elongation/enlargement (usually signalling distal obstruction, or in continent diversions infrequent catheterization); persistent high pressure can deteriorate renal function, and enlargement may cause segmental volvulus.

Abdominal Stoma

Two types: flush (preferred for continent diversion managed by intermittent catheterization) and protruding (preferred when a collection appliance is worn — lower stomal stenosis, better appliance fit, fewer skin problems). Mark the site preoperatively in both sitting and supine positions. All stomas should pass through the belly of the rectus muscle — a site lateral to the rectus sheath invites parastomal hernia. In paraplegic patients, place the stoma in the upper abdomen whenever possible (a right-lower-quadrant stoma is hard to see and gets squeezed between abdomen and thigh).

Nipple ("rosebud") stoma — the bowel is everted to make a nipple ~2–3 cm long; seromuscular myotomies before construction adhere serosa-to-serosa and reduce stomal retraction, particularly useful in the obese.
Loop end ileostomy — easier than an ileal end stoma in the obese patient.
Complications: stomal stenosis (most common — leaving a catheter through the stoma nightly may reduce the need for revision; the likeliest cause of an elongated, dilated conduit with hydronephrosis and hyperchloremic acidosis), retraction, prolapse, parastomal hernia (more common with loop than end stomas — best managed by relocating the stoma to the other side and closing the defect), bowel necrosis, bleeding (if extremely difficult to control, suspect cirrhosis/varices — portal decompression may be required), dermatitis, and obstruction.

Ureterointestinal Anastomoses

The ureter may be joined to small bowel or colon in a refluxing or non-refluxing fashion; whether either is superior is controversial.

Type	Techniques
Ureterocolonic	Leadbetter-Clarke, Strickler, Pagano, Goodwin transcolonic, Cordonnier and Nesbit
Small bowel	Bricker, Wallace, Le Duc (and others)

Bricker — a refluxing end-to-side ureter–small bowel anastomosis; relatively simple, low complication rate; stricture ~6%, leak ~3% without stents (negligible with stents). Spatulate the ureter ~0.5 cm and suture full-thickness ureter to full-thickness bowel with 5-0 PDS, stented.
Wallace — a refluxing end-to-end anastomosis with the lowest complication rate of any technique. Avoid it in patients with extensive CIS or high risk of recurrent ureteral tumour, because a recurrence at the anastomosis could obstruct both ureters and cause uremia.
Le Duc — a non-refluxing technique (ureter laid down on an ileal trough).
Antireflux valves — three common types: ileocecal intussusception, ileoileal intussusception, and an ileal nipple valve placed into colon.

Complications of ureterointestinal anastomoses (5):

Leakage (fistula) — typically within 7–10 days; may cause periureteral fibrosis and stricture; incidence 3–9%, reduced nearly to 0 with soft Silastic stents.
Stricture — caused by ischemia, urine leak, radiation, or infection; antireflux techniques have a higher stricture rate. A stricture away from the anastomosis is most common in the left ureter where it crosses the aorta beneath the inferior mesenteric artery (from aggressive adventitial stripping/angulation). Endourologic outcomes are less favourable for strictures <1 year from surgery, ≥1.5 cm, left-sided, or with renal-function deterioration; re-exploration with excision and reanastomosis is most successful.
Renal function deterioration — usually from lack of ureteral motility, infection, or stones, but can reflect anastomotic obstruction.
Acute pyelonephritis — early and long-term; incidence 10–20% with ileal conduits, 9% with antirefluxing colon conduits.
Reflux in anastomoses designed to prevent it.

Postoperative Care

Routine nasogastric/gastrostomy decompression for ileus is somewhat controversial, though a nasogastric tube reduces postoperative vomiting. Fluid lost via a nasogastric tube used for paralytic ileus is isotonic and alkaline and should be replaced with Lactated Ringer's (providing potassium, chloride, and bicarbonate); saline with KCl is more appropriate for replacing acidic gastric secretions. Clear liquids begin when ileus resolves and are advanced as tolerated (typically 1–4 days); start IV nutrition if the patient is malnourished preoperatively, a complication delays feeding, or ileus persists on postoperative day 5. Enhanced recovery after surgery (ERAS) protocols reduce variation in perioperative care — a 2016 meta-analysis (Tyson & Chang; 13 studies) found reduced complications, faster return of bowel function, and shorter length of stay, with no difference in overall readmissions (slightly fewer at 30 days).

Metabolic and Other Complications of Urinary Intestinal Diversion

Complications fall into three categories: metabolic (altered solute reabsorption by the bowel holding urine), neuromechanical (gut configuration affecting storage/contraction), and technical-surgical. The metabolic complications follow the mnemonic LSD ORGASMIC: Lytes, Sensorium, Drug metabolism, Osteomalacia, Renal function, Growth retardation, Acidosis/alkalosis, Stones, Malabsorption, Infection, Cancer.

Electrolytes — the segment used, its surface area, urine dwell time, urinary solute concentration, renal function, and pH all influence absorption:

Segment	Derangement	Treatment
Stomach	Hypochloremic, hypokalemic metabolic alkalosis (mainly with concomitant renal failure; lethargy, respiratory insufficiency, seizures, ventricular arrhythmias)	H2 blocker + rehydration
Jejunum	Hypochloremic, hyperkalemic, hyponatremic metabolic acidosis (worse with more proximal segment; may be worsened by hyperalimentation)	Rehydrate with NaCl, correct acidosis with NaHCO₃; thiazide may help the hyperkalemia (with normal renal function it is corrected by renal secretion)
Ileum or colon	Hyperchloremic metabolic acidosis (ionized transport of ammonium); ~16% of ileal-conduit patients need treatment	Oral NaHCO₃, or potassium/sodium citrate (Polycitra) if sodium load is a problem; block chloride transport

Hypokalemia and total-body potassium depletion can occur (most common with ureterosigmoidostomy); if it coexists with severe hyperchloremic acidosis, replace potassium and correct the acidosis with bicarbonate.

Sensorium — altered by magnesium deficiency, drug intoxication, or abnormal ammonia metabolism. Ammoniagenic coma is most often associated with decreased liver function: ammonium excreted by the kidney is reabsorbed by the bowel segment, returned via the portal circulation, and normally cleared by the liver. It can occur with normal hepatic function if systemic bacteremia/endotoxin or urea-splitting UTIs overwhelm hepatic clearance. Manage with prompt urinary drainage, treatment of urinary pathogens with systemic antibiotics, and oral neomycin or lactulose to reduce gut ammonia absorption.

Drug metabolism — drugs absorbed by the GI tract and excreted unchanged by the kidney are re-exposed to and reabsorbed by the bowel segment, reaching toxic levels — reported with phenytoin, methotrexate, lithium, and theophylline. Consider draining a continent pouch during chemotherapy.

Osteomalacia (renal rickets) — from persistent acidosis, vitamin-D resistance, or excessive renal calcium loss; patients report lethargy, weight-bearing joint pain, and proximal myopathy. Treat by correcting acidosis and supplementing calcium.

Renal function — ~20% of patients experience significant progressive deterioration regardless of diversion type; sepsis and renal failure are more common with ureterosigmoidostomy (acquired renal disease is the most common cause of death beyond 15 years). More renal function is needed for continent than for short-conduit diversion. eGFR cut-offs for continent diversion vary by source (Campbell's ch.97 >40, ch.99 >35–40; 2019 AUA MIBC >45 mL/min). A patient with serum creatinine >2 mg/dL (177 µmol/L) may still be considered if they can achieve urine pH ≤5.8 after an ammonium-chloride load, urine osmolality ≥600 mOsm/kg after water deprivation, GFR >35 mL/min, and minimal proteinuria. Because urea and creatinine are reabsorbed by ileum and colon, serum levels may not reflect true renal function — fractional excretion of sodium most accurately measures renal function in a diverted patient.

Growth retardation — conduits impair linear growth and increase fracture risk and orthopedic complications.

Acidosis/alkalosis — most ileal and colonic segments retain the ability to generate a hyperchloremic metabolic acidosis over time.

Stones — risk factors include persistent infection (magnesium-ammonium-phosphate/struvite stones), a foreign body (staple or non-absorbable suture) as a nidus, and altered bowel mucus that interferes with emptying.

Malabsorption — with significant ileal loss: vitamin B12 malabsorption (anemia and neurologic deficits, but the liver's 3–5-year B12 store delays this for years) and bile-salt malabsorption. Three mechanisms of diarrhea with an ileal conduit: bile-salt malabsorption; fat malabsorption (loss of the "ileal brake" presenting unmetabolized lipid to the colon); and loss of the ileocecal valve (bacterial reflux into ileum → small-intestinal bacterial overgrowth). Loss of significant jejunum → malabsorption of fat, calcium, and folic acid; loss of colon → diarrhea from impaired fluid/electrolyte and bicarbonate handling.

Infections — ~75% of ileal-conduit urine specimens are infected, but many patients are asymptomatic; upper-tract deterioration is more likely when cultures become dominant for Proteus or Pseudomonas — treat relatively pure Proteus/Pseudomonas cultures, observe asymptomatic mixed cultures. Pouchitis is common early when mucus accumulation is high (mechanical irrigation reduces infections). Pyocystis occurs in ~20% of supravesical-diversion patients (malodorous discharge, possible sepsis); if conservative bladder irrigation fails, vaginal vesicostomy is effective in women (good for elderly/high-risk patients) and cystectomy is effective and usually required in men.

Cancer — bladder cancer after augmentation presents at a younger age, with atypical symptoms (vague abdominal pain, urosepsis, recurrent UTI, difficult catheterization, renal failure) and signs (new hydronephrosis, wall thickening), often advanced, usually ≥10 years after augmentation; most are adenocarcinomas (also adenomatous polyps, sarcomas, urothelial carcinoma). Cancer develops in 6–29% (mean ~11%) of ureterosigmoidostomy patients — they need scheduled colonoscopy. Defunctionalized ureterointestinal anastomoses carry an adenocarcinoma risk and should be excised rather than ligated and left in situ.

False-positive pregnancy test — male and female diverted patients can have false-positive urinary pregnancy tests, possibly from mucus.

Ruptured augmented bladder — up to 50% of cystograms are falsely negative, so a negative study does not exclude rupture; confirm with a CT cystogram using ≥300 mL of contrast, imaging the bladder distended and emptied.

Neuromechanical Aspects

Two properties matter: volume–pressure and motor activity. Splitting (detubularizing) most segments increases volume by ~50%; the goal is a spheric reservoir (maximum volume for the least surface area), and capacity increases over time only if the reservoir is regularly filled. Detubularization is thought to discoordinate motor activity and lower intraluminal pressure, but the literature is contradictory; over years some neobladders become flaccid, requiring intermittent catheterization.

Orthotopic Urinary Diversion

Background and Principles

Ureterosigmoidostomy is the oldest form of urinary diversion; diversion has since developed along three paths — conduit, continent cutaneous, and orthotopic. The orthotopic neobladder most closely resembles the native bladder in location and function: it relies on the intact external rhabdosphincter for continence, seldom requires intermittent catheterization, and is emptied by pelvic-floor relaxation plus a Valsalva increase in intra-abdominal pressure. Compared with continent cutaneous diversion it allows natural voiding, is simpler to build, and less often needs revision. The finding that urethral involvement is rare without bladder-neck tumour enabled its use in women.

Three principles for a successful continent orthotopic diversion:

An adequate external sphincter and a non-obstructed urethra.
A compliant reservoir (low pressure throughout filling) — best achieved by opening the bowel longitudinally to fully detubularize it and folding it into a sphere.
A capacious reservoir (≥300–500 mL once mature) for reasonable voiding intervals.

All bowel segments stretch over time given adequate outflow resistance, though colon stretches less readily; small bowel has better wall compliance, stretches more, and produces less mucus.

Patient Selection

From a purely medical standpoint, ~80–90% of male and ~75% of female cystectomy patients are potential neobladder candidates. Contraindications (6):

Insufficient bowel length — ileal reservoirs need 60–75 cm vs 10–15 cm for an ileal conduit; in patients with multiple prior bowel resections (e.g. Crohn's) consider a sigmoid neobladder to avoid short-bowel syndrome. Where possible, take down the old bowel anastomosis and use that site as one end of the reservoir to avoid devascularizing the intervening segment.
Unwillingness or inability to self-catheterize — all candidates must be willing/able, as retention can occur years later and cannot be reliably predicted.
Renal insufficiency — eGFR <45 mL/min (2019 AUA MIBC); a patient with creatinine >2 mg/dL may still qualify if GFR >35 mL/min, urine pH ≤5.8 after an ammonium load, osmolality ≥600 mOsm/kg after water deprivation, and minimal proteinuria.
Hepatic dysfunction.
Urethrectomy indications — positive urethral margin; in males, high-grade or invasive urethral disease distal to the prostatic urethra or suspected prostatic stromal involvement; in females, bladder-neck tumours. (Bladder CIS, multifocal tumour, bladder-neck involvement, and locally advanced disease are not in themselves contraindications.)
Severe urethral stricture disease.

The first four also apply to non-orthotopic continent cutaneous diversions.

Oncologic considerations — locally advanced stage and extravesical disease should not, by themselves, preclude orthotopic diversion: local recurrence is relatively infrequent even with locally advanced or node-positive disease, many such patients are long-term survivors, careful urethral preservation does not increase recurrence risk, and if local recurrence does occur only a minority develop problems related to the diversion itself.

Other patient factors — general health and social circumstances, baseline renal/hepatic function, a healthy urethra and functioning sphincter, manual dexterity, prior pelvic radiation/prostate surgery/bowel resection, and personal preference. The frail elderly or those with poor cognition/difficult social circumstances are usually best served by an ileal conduit; chronologic age and obesity are not contraindications.

Prior pelvic radiation — orthotopic reconstruction is possible in carefully selected patients after full-dose irradiation, but ileum should not be used if irradiated. Prior high-dose prostate radiation/brachytherapy or cervical-cancer implants scar the rhabdosphincter area more than external-beam bladder radiation. Mandatory preoperative cystoscopy assesses mucosal integrity near the sphincter; counsel that diversion may prove impossible intraoperatively.
Prior prostate surgery — dissection at the prior vesicourethral anastomosis is difficult but usually feasible; a patient continent after radical prostatectomy can expect an acceptable neobladder result.
External sphincter damage — poor sphincter function in a highly motivated patient may be managed with a concomitant or delayed anti-incontinence procedure.

Continence-Preserving Technique

The striated rhabdosphincter is innervated by branches of the pudendal nerve and is the key to neobladder continence; its fibres concentrate anterior and lateral to the proximal urethra. Dissection at the prostatic apex (men) or bladder neck (women) must be precise to preserve continence without compromising the oncologic result — obtain careful control of the dorsal venous complex and avoid deep suture bites into the pelvic floor.

In women, leave the endopelvic fascia and levators undisturbed and dissect the bladder off the anterior vaginal wall rather than excising it where oncologically safe. Preserving the uterus and its supportive ligaments eliminates the risk of vaginal fistula, improves sexual function, may decrease urinary retention, and improves daytime continence. Nerve-sparing in women is controversial, and perivaginal-nerve preservation may not be strictly required for continence.

Reservoir Construction

Excellent voiding outcomes are achievable with any segment provided the rhabdosphincter is preserved and an adequate-capacity, low-pressure reservoir is built. Detubularized ileum (or ileum + colon) gives the greatest compliance and lowest chance of high-pressure contractions; stomach and sigmoid colon have particularly poor compliance and high pressures.

Advantages of an ileal neobladder (6): larger capacity, lower filling pressures, lower maximum-capacity pressures, better compliance, a more mobile mesentery (reaches the urethra easily; a "tail" such as the Studer's can reach the renal pelvis), and decreased mucus/electrolyte reabsorption as the mucosa atrophies over time (more reliable than in colon). The main disadvantage is potential loss of vitamin B12 absorption. Contraindications to ileum (3): short bowel syndrome, inflammatory small bowel disease, extensive prior pelvic irradiation. An antireflux mechanism does not appear necessary to protect the upper tracts in the intermediate term and may itself cause (often silent) obstruction.

All reservoirs are closed with continuous absorbable suture — non-absorbable suture and metal staples are avoided because of stone formation. Ileal reservoirs use 60–75 cm of detubularized terminal ileum; the two most popular are the Hautmann W-neobladder and the Studer pouch, with the T-pouch and extraserosal-tunnel techniques adding an antireflux mechanism when desired.

Hautmann (W) pouch — an intentionally large-capacity spheric reservoir (~70 cm, M/W configuration) that may aid early continence but can increase late retention and electrolyte reabsorption.
Studer pouch — a double-folded U reservoir with a long afferent isoperistaltic tubular ileal limb thought to prevent reflux during Valsalva voiding; simple to construct, needs no staples, and accommodates short ureters.
Camey II — a serous-lined extramural tunnel design.
Kock / hemi-Kock ileal reservoir — used intussuscepted nipple valves (afferent antireflux ± efferent continence); now mostly historical because of valve-related technical difficulty and complications.
T-pouch — a serous-lined ureteral-tunnel modification preserving antireflux while avoiding Kock nipple-valve complications.

Colon and ileocolic pouches — a good option for multiple prior small-bowel resections or diseased ileum (Crohn's, prior radiation). Colon is less distensible and may generate higher pressure waves, so the initial volume should be larger than for ileum; combining colon with ileum mitigates this. Variants include the orthotopic Mainz (Mainz III), Le Bag, right-colon, and sigmoid pouches (a redundant sigmoid is often readily available; watch for compromised distal-colon vasculature from internal-iliac branch interruption during cystectomy).

Minimally invasive techniques — modest recovery improvement with longer operative times but less blood loss and mixed complication data; in RAZOR, 20–24% underwent neobladder diversion.

Perioperative management — place a pelvic drain in every patient (leave until the pouch heals, given occasional late leakage). Most authors stent the ureters early; at ~3 weeks, if drain output is minimal (<100 mL/24 h) the catheter is removed followed by the drain. Routine pouchograms are not performed unless drain output is significant.

Complications of Orthotopic Diversion

Overall complication, length-of-stay, and reoperation rates are not increased versus ileal conduit. Early and late complications (bleeding, infection, thrombotic/cardiovascular/pulmonary/GI events, bowel obstruction, ureteral problems) occur at similar rates across diversion types. Urine leaks are more common in continent diversions because of long suture lines but usually resolve with good catheter drainage and stents (if no urinoma forms); ~5% need a percutaneous drain or nephrostomy early, as open repair is very difficult in the first weeks. Ventral hernias are common and may relate to the increased abdominal pressure needed to empty the pouch.

Late complications directly related to the diversion include UTI, ureteroileal/afferent-limb obstruction, urethral stricture, upper-tract and pouch stones, pouch-vaginal fistula, pouch perforation, incontinence, and urinary retention — most (other than incontinence and retention) are less common in orthotopic than continent cutaneous diversion and can often be managed endoscopically.

UTI — asymptomatic bacteriuria/colonization is common and should not be treated; confirm symptomatic infection by culture. A febrile infection after the first few months warrants evaluation for upper-tract obstruction and incomplete emptying.
Ureteroileal / afferent-limb obstruction — stricture rate equals that of ileal conduit; the direct end-to-side Leadbetter or combined Wallace anastomosis with interrupted fine absorbable sutures has the lowest stricture risk (~3–6%). Antireflux-valve obstruction can be silent until bilateral hydronephrosis or renal failure.
Urethral stricture — actual neobladder-urethral anastomotic stricture is rare.
Pouch stones — common in the Kock neobladder (staples for the nipple valve) but rare in the all-absorbable Studer and Hautmann pouches.
Pouch-vaginal fistula — a complication unique to female neobladders (incidence 5–10%; higher if anterior vaginal wall is excised or the patient is irradiated). Prevent by leaving the vagina intact when oncologically safe, watertight vaginal-cuff closure, and interposing an omental flap. Suspect (and rule out with pelvic exam ± methylene blue) in any woman with persistent significant incontinence after the first few months.
Pouch perforation — potentially life-threatening but rare (low outlet resistance); risk increased after prior radiation; presents with acute abdominal pain, distention, and often sepsis; CT cystogram is usually diagnostic; generally managed by exploration and repair.

Incontinence — neobladders are generally less continent at night than by day.

Daytime continence improves over the first 6–12 months and is ultimately achieved in 80–90% of men and women (uterine preservation may improve it).
Nighttime continence improves more slowly (may continue beyond 12 months) and persists as a bother in 20–50% — partly from absent neurologic feedback/sphincter-detrusor reflex and decreased nighttime sphincter tone.
Factors: age (older patients take longer), intestinal segment used, and possibly nerve-sparing. Delay evaluation/management until the pouch has expanded (6–12 months). Pelvic-floor physiotherapy with biofeedback may help; urodynamics (especially with colon) can confirm adequate, pressure-stable capacity; reduced urethral closure or low Valsalva leak-point pressure may warrant bulking agents, an artificial urinary sphincter, or a sling (infrapubic bone anchors or a prepubic approach are safest to avoid pouch/bowel injury).

Urinary retention — occurs in 4–10% of males and 20–60% of females, and risk increases with time. Patients may present with acute retention, but more often with UTIs or new overflow incontinence, or are found with a palpable suprapubic mass/distended reservoir/new hydronephrosis. Perform rectal/vaginal exam and cystoscopy to exclude an anastomotic stricture or tumour recurrence. Management favours intermittent self-catheterization (pharmacotherapy is ineffective); biofeedback for pelvic-floor relaxation may help, and an obstructing mucosal flap can be incised endoscopically. Repair abdominal-wall/incisional hernias (common, and they reduce the ability to raise intra-abdominal pressure to empty); in women, posterior pouch prolapse may contribute, and posterior support (omental flaps, sacrocolpopexy) has been advocated.

Follow-up

There is no consensus regimen; follow-up is divided into three periods:

Early (first 4 months) — identify early ureteroileal anastomotic strictures (technical or poorly vascularized distal ureters).
Middle (4 months–3 years) — focus on cancer recurrence, best with CT/cross-sectional imaging (also assessing upper tracts and reservoir for stones/obstruction); frequency risk-adapted to cystectomy pathology.
Long-term (beyond 3 years) — detect pouch stones, late upper-tract obstruction, and urothelial carcinoma of the urethra or upper tracts. Include rectal/pelvic exam and urethral cytology — urethral recurrence occurs in ~10% of males and rarely in females.

Quality of Life

There are no clear data showing an overall quality-of-life advantage for neobladders, and most patients adapt to whatever their diversion requires. Still, given the option most choose orthotopic diversion as the most natural choice that avoids a stoma, and offering it may encourage patients to undergo definitive cancer treatment — provided they have realistic expectations about incontinence and possible self-catheterization.

Indiana Pouch

A non-orthotopic continent cutaneous diversion using a buttressed ileocecal valve as a continence mechanism robust to intermittent catheterization. It isolates ~10 cm of terminal ileum with the entire right colon (to the right/middle colic artery junction); after restoring bowel continuity and appendectomy, the right colon is opened and ureteral-taenial implants fashioned, and the ileocecal valve is double-imbricated with interrupted nonabsorbable Lembert sutures. Early complications: pouch leak, transient small bowel obstruction. Late: incontinence, stomal stenosis, parastomal hernia, stones, small bowel obstruction.

Self-Test

1. List five differences between the ileum and jejunum. Ileum — more distal, smaller diameter, multiple arterial arcades, smaller arcade vessels, thicker mesentery. Jejunum — more proximal, larger diameter, single arcades, larger arcade vessels, thinner mesentery.

2. What is the safe maximum distance of bowel that will survive away from a straight vessel? ~8 cm (up to 15 cm experimentally).

3. Which bowel segments should be avoided in a patient with prior pelvic radiation? The last 2 inches of terminal ileum, and the 5 feet of small bowel beginning ~6 feet from the ligament of Treitz.

4. What are the potential weak points in the colonic blood supply? Sigmoid–superior hemorrhoidal junction (Sudeck's point), middle–right colic midpoint, and middle–left colic midpoint.

5. What are the potential advantages of a stomach conduit? Electrolyte imbalance rare with normal renal function; net chloride/hydrogen excretion (helps pre-existing acidosis); no malabsorption (option in short bowel syndrome); usually outside radiation fields; less mucus; acidic pH reduces bacterial colonization.

6. Which bacterial flora are found in the bowel? Aerobes — E. coli and Enterococcus faecalis; anaerobes — Bacteroides and Clostridium.

7. What is the bacterial concentration in the jejunum, distal ileum, ascending colon, and descending colon? ~10–10⁵, 10⁵–10⁷, 10⁶–10⁸, and 10¹⁰–10¹² organisms per gram, respectively.

8. What is the goal of mechanical vs antibiotic bowel preparation? Mechanical reduces the total bacterial load (amount of feces); antibiotic reduces the bacterial concentration.

9. What are the contraindications to whole-gut irrigation? Obstructed bowel, unstable cardiovascular system, congestive heart failure, cirrhosis, and severe CKD.

10. What are the principles of intestinal anastomosis? Adequate exposure; adequate blood supply; prevention of enteric spillage; watertight serosal apposition without tension; sutures not strangulating; and realignment of the two mesenteries.

11. List the contraindications to using ileum for a conduit. Short bowel syndrome, inflammatory small bowel disease, and extensive prior pelvic radiation.

12. List contraindications to transverse, sigmoid, and ileocecal conduits. Sigmoid — internal iliac artery ligated with rectum in situ, extensive pelvic irradiation. Ileocecal — inflammatory large bowel disease, disease of the segment, severe chronic diarrhea.

13. Which bowel segment has the highest rate of postoperative bowel obstruction? Ileum.

14. What are the risk factors for bowel anastomotic breakdown? Poor blood supply, local fecal spillage, a drain on the anastomosis, and radiation.

15. List three techniques for anastomosing the ureter to small bowel. Bricker (end-to-side), Wallace (end-to-end), and Le Duc (non-refluxing, laid on an ileal trough).

16. Which ureter–small bowel technique has the lowest complication rate? Wallace.

17. List complications of ureterointestinal anastomoses. Leakage/fistula, stricture, renal-function deterioration, acute pyelonephritis, and reflux (in antireflux constructions).

18. List the metabolic complications of urinary intestinal diversion. LSD ORGASMIC — Lytes, Sensorium, Drug metabolism, Osteomalacia, Renal function, Growth retardation, Acidosis/alkalosis, Stones, Malabsorption, Infection, Cancer.

19. What are the electrolyte derangements by segment? Ileum/colon — hyperchloremic (hypokalemic) metabolic acidosis; jejunum — hypochloremic, hyperkalemic, hyponatremic metabolic acidosis; stomach — hypochloremic, hypokalemic metabolic alkalosis.

20. Which diversion segment is associated with elevated aldosterone? Elevated renin? Elevated aldosterone — stomach; elevated renin — jejunum.

21. What is the treatment of hyperchloremic metabolic acidosis in an ileal-conduit patient? Oral sodium bicarbonate (substitute potassium/sodium citrate when a sodium load is undesirable for cardiac/renal disease).

22. What renal-function parameters are recommended before continent diversion? eGFR >45 mL/min (2019 AUA MIBC); minimal proteinuria; urine pH ≤5.8 after an ammonium-chloride load; and urine osmolality ≥600 mOsm/kg after water deprivation.

23. List three mechanisms of diarrhea associated with an ileal conduit. Bile-salt malabsorption, fat malabsorption (loss of the ileal brake), and loss of the ileocecal valve (bacterial overgrowth).

24. What deficiencies result from malabsorption when jejunum is used for diversion? Fat, calcium, and folic acid.

25. When should asymptomatic bacteriuria in a urinary diversion be treated? When the culture is relatively pure Proteus or Pseudomonas.

26. What is the expected histology of a bladder cancer associated with urinary diversion? Adenocarcinoma.

27. What are the contraindications to orthotopic urinary diversion? Urethrectomy indications (positive urethral margin; in men high-grade/invasive disease distal to the prostatic urethra or suspected prostatic stromal invasion; in women bladder-neck tumours); renal insufficiency (eGFR <45 mL/min); significant proteinuria or inability to acidify (pH <5.8 after ammonium load) or concentrate (≥600 mOsm/kg after water deprivation) the urine; hepatic dysfunction; inability/unwillingness to self-catheterize; insufficient bowel length; and severe urethral stricture disease.

28. What electrolyte abnormality develops in patients with renal insufficiency and a neobladder? Hyperchloremic metabolic acidosis.

29. What is the possible benefit of preserving the uterus in women undergoing neobladder reconstruction? Reduced risk of vaginal fistula, improved sexual function, reduced risk of urinary retention, and improved daytime continence.

30. What is the target volume of a mature neobladder, and how much bowel is used for a neobladder vs an ileal conduit? Target volume ~300–500 mL; an ileal neobladder uses ~60–75 cm vs ~10–15 cm for an ileal conduit.