Urinary Diversions and Neobladders 

Updated: Feb 05, 2019
Author: Joseph A Costa, DO; Chief Editor: Bradley Fields Schwartz, DO, FACS 

Overview

Background

Urinary diversion is indicated when the bladder can no longer safely function as a reservoir for urine storage. This article covers the most common types of diversion, the most common indications for diversion, and the most common early and late complications following urinary diversion. See the image below.

Close-up photograph of continent urinary diversion Close-up photograph of continent urinary diversion using ileum.

For patient education resources, see eMedicineHealth's Bladder Cancer.

History of the Procedure

Surgeons have been performing urinary tract diversions for almost 150 years. In 1852, Simon performed the first ureteroproctostomy in a patient with exstrophy. Since then, the procedures have been refined, and patient outcomes have improved. Currently, urinary tract diversions are separated into two standard categories: continent diversions and noncontinent diversions, which necessitate external ostomy collecting devices. Further historical milestones of urinary diversion are as follows:

  • 1851 - Ureteroproctostomy (Simon)

  • 1878 - Ureterosigmoidostomy (direct anastomosis) (Smith)

  • 1898 - Rectal bladder (Gersuny)

  • 1950s - Ileal loop (Bricker)

  • 1959 - Ileal neobladder (Camay)

  • 1970s - Koch pouch

  • Early 1980s - Indiana pouch

  • Late 1980s - Orthotopic diversion

Problem

Noncontinent urinary diversion

Diversion into a noncontinent conduit is considered less technically demanding and is associated with the fewest postoperative complications; therefore, this technique is the criterion standard. Noncontinent urinary diversion is performed by either directly anastomosing the ureters to the anterior body wall (ie, cutaneous ureterostomy) or using a segment of bowel to anastomose in a similar manner to the anterior wall for ostomy bag drainage.

The bowels most commonly used for noncontinent conduit diversion are 15-25 cm of ileum (see the image below), colon, and, least often, jejunum bowel segments. These segments usually lend themselves to easy mobilization on a vascular pedicle, which allows for ureter anastomosis at the proximal end and stoma formation on the abdominal wall (most often in the right lower quadrant) at the distal end. In order to promote drainage and to minimize urine reflux, ensuring that the urine flows in a properistaltic manner relative to bowel segment motility is important.

Noncontinent urinary diversion with ileum. Courtes Noncontinent urinary diversion with ileum. Courtesy of Karl Kreder, MD.

Direct ureter anastomosis with the skin is the only form of diversion that does not require use of the gastrointestinal tract. In pediatric patients, cutaneous ureterostomy is often performed as a temporizing measure prior to a future and more definitive procedure. In adults, cutaneous ureterostomy is currently rarely performed.

Continent urinary diversion

The most commonly used bowel segments for continent urinary diversion are either ileum (as depicted below) or a combination of terminal ileum and ascending colon. Ensuring that all continent diversions store and empty urine at low pressures is paramount. High storage and voiding pressures ultimately cause high-pressure reflux nephropathy and may result in renal failure; therefore, all bowel segments used for continent diversion, with the exception of their use in a ureterosigmoidostomy procedure, are initially detubularized. The bowel segments are then refashioned in a more spherical shape, which increases capacity and decreases luminal pressure by a magnitude of 3- to 4-times lower than the original segmental pressure.

Continent urinary diversion using ileum. Continent urinary diversion using ileum.

Orthotopic diversion (ortho meaning correct, topic meaning of a place) is a term that describes the reconstructed pouch anastomosed to the native urethra. Neobladder is a term used synonymously with orthotopic diversion. The continence mechanism in an orthotopic diversion is the native urethral rhabdosphincter. Continent diversion may be further categorized into 3 types: (1) orthotopic or neobladder diversion, (2) continent catheterizable diversion, and (3) ureterosigmoidostomy.

Patients with a continent catheterizable stoma have a one-way valve mechanism fashioned at the insertion site that leads into the urinary storage system. The limb allows for catheterization through a small stoma on the abdominal wall, enabling the system to empty; however, this limb remains continent during the storage phase between catheterizations. Mechanisms for continence of the efferent limb include a flap valve, nipple valve, pressure equilibration, or combinations of thereof. Ureterosigmoidostomy consists of anastomosing the ureters to the sigmoid colon in a nonrefluxing manner. This diversion method relies on the anal sphincter for continence. For reasons listed in Complications, ureterosigmoidostomy is becoming a less popular method of continent diversion. See the image shown below.

Ileocecal urinary diversion using a plicated effer Ileocecal urinary diversion using a plicated efferent limb and catheterization; ureters are anastomosed into the bowel wall. Courtesy of Karl Kreder, MD.

Epidemiology

Frequency

Bladder cancer is the fourth most common cancer in the United States. Bladder cancer is 3 times more common in men than in women and is 1.5-2 times more common in white Americans than in black Americans.

For additional information on bladder cancer, see Medscape’s Bladder Cancer Resource Center.

Etiology

The most common indications for urinary system diversion are as follows:

  • Bladder cancer requiring cystectomy

  • Neurogenic bladder conditions that threaten renal function

  • Severe radiation injury to the bladder

  • Intractable incontinence in females

  • Chronic pelvic pain syndromes

Pathophysiology

The pathophysiology of the specific indications for urinary diversion listed above is well reviewed in other Medscape Reference articles and is not addressed here.

The pathophysiology of urinary diversion is best described by the interaction of stored urine with the mucosal lining of bowel segments. The inherent property of all bowel segments is that they absorb components of fluids with which they are in contact. Therefore, the urologist who treats patients with urinary diversions is presented with many unique clinical challenges. Specific details regarding the metabolic abnormalities and other problems experienced are discussed further in Complications.

Presentation

Patients who require urinary diversion are often monitored for a time by their urologist, and the decision for surgical intervention is made if conservative management fails. Patients with complications of urinary diversion may present to the primary care physician at any time. Because the complications of urinary diversion are the most common clinical presentation to the primary provider in the urgent setting, this section focuses on the clinical presentation of complications.

Most often, patients with complications of urinary diversion present with an appearance of obvious illness. In the 1950s, Ferris and Odel described the classic presentation of such patients, which consisted of easy fatigability, weakness, anorexia, weight loss, polydipsia, nausea, vomiting, and diarrhea.[1] Additionally, these patients may be bacteremic or septic due to overgrowth in their often-colonized urinary reservoirs or conduits.

The hallmark metabolic abnormality observed in a patient with a jejunal conduit is hyperkalemic, hypochloremic, hyponatremic metabolic acidosis. Patients with ileal conduits, colon conduits, or continent reservoirs tend to present with hyperchloremic metabolic acidosis with normal or low potassium levels.

Patients with urinary retention usually present with abdominal pain and distension. This condition is a medical emergency, and drainage of the reservoir is indicated. Haupt et al reported on a patient with an orthotopic bladder who produced enough mucous to result in bladder outlet obstruction and reservoir rupture.[2]

In patients who have undergone ileal resection for diversion and present with megaloblastic anemia, vitamin B-12 deficiency should be considered.

Patients with continent reservoirs are at risk for secretory and/or osmotic diarrhea, depending on the length of ileum used and whether the ileocecal valve was resected for construction of the urinary pouch. Diarrhea and the metabolic abnormalities discussed above result in a presentation that consists primarily of dehydration.

Indications

Conservative nonoperative medical therapy is the first modality of choice in the management of any spinal abnormality, whether traumatic or congenital. Surgical diversion or augmentation of the urinary tract is indicated only when other less-invasive options have failed. The primary indications for diversion include preservation of renal function, prevention of recurrent infection, and elimination of the need for permanent indwelling catheters.

Indications for diversion arise when the native bladder becomes inherently dangerous to the host. The most common indications for diversion are as follows, in descending order of frequency:

  • Bladder cancer requiring cystectomy

  • Neurogenic bladder conditions that threaten renal function

  • Severe radiation injury to the bladder

  • Intractable incontinence in females

  • Chronic pelvic pain syndromes

Indications for diversion of the upper urinary tract may be divided into malignant and benign disease. Cancer may involve the bladder as a primary lesion, or the bladder may be involved with cancer originating in contiguous pelvic organs. In either case, a radical bladder excision, at times, may provide the patient's best chance for long-term survival.

Patients who present with muscle-invasive tumors (T2 or greater tumor stage) or those who have a particularly aggressive and/or progressive T1 tumor stage are most often treated with a radical cystectomy. The cystectomy includes a radical prostatectomy in men and a hysterectomy with or without an anterior layer of vaginal tissue in women.[3, 4]

Neurogenic conditions that require urinary diversion are most often caused by either traumatic or congenital etiologies. Traumatic spinal cord injury most often affects men aged 16-35 years. Of patients who experience spinal cord trauma, 25% are incomplete quadriplegics, 25% are complete quadriplegics, 25% are incomplete paraplegics, and 25% are complete paraplegics. After spinal shock resolves, the patient's bladder often stores and empties urine in a relatively predictable pattern.

Myelodysplasia is the most common congenital spinal abnormality and the most common etiology of a neuropathic bladder in children. Myelodysplasia occurs in approximately 1 per 1000 births in the United States. In the last half century, the incidence of neural tube defects at birth has decreased, likely because of increased prenatal diagnosis and pregnancy termination. Most patients with myelodysplasia are treated with bladder augmentation; however, some patients require urinary diversion. Approximately 40% of children with myelodysplasia are at high risk for upper urinary tract changes, and approximately 6-8% of these patients require surgical intervention.

Benign disease usually involves elevated storage pressure of the native bladder, which is inherently dangerous to the upper urinary tract. Less commonly, diversion is indicated for patients with intractable incontinence or chronic pelvic pain syndromes. In men, the prostate is usually removed with the bladder, whether the indication is benign or malignant in nature. When treating benign disease in women, the decision to perform a bladder excision is based more on the surgeon's preference.

Chronic pelvic pain syndromes most commonly arise from bladder cancer. Congenital or traumatic injury to the spinal cord often leads to abnormal urinary storage and emptying. Most often, the neuropathic abnormalities are managed in a nonoperative manner. Occasionally, surgical diversion or urinary tract augmentation is required.

Other specific conditions may include abnormally high urinary storage pressures, often observed late in an areflexic bladder that never recovers function after spinal shock. This condition is also common in patients with detrusor external sphincter dyssynergy.

Relevant Anatomy

Anatomy relevant to urinary diversion is primarily associated with the bowel blood supply, specifically, branches of the superior mesenteric artery. Both continent and noncontinent urinary diversions are performed with the use of ileum as shown below, ascending colon, or both or with transverse colon and, occasionally, sigmoid colon. Each bowel segment must be mobilized on its mesenteric pedicle, respecting the major arterial supply on which it depends for survival.

Schematic diagram of continent urinary diversion w Schematic diagram of continent urinary diversion with ileum. Courtesy of Karl Kreder, MD.

Because regular variation exists in arterial branches of the ileum and large bowel, most arcades are identified intraoperatively by examination and back lighting in order to preserve the proper plexus.

Diversion with ileal segments usually begins at least 15 cm from the ileocecal valve and involves segments from 15-80 cm in length, depending on the surgeon's goals. The ileocolic arterial branch and relevant marginal arterial arcade are most often the source of the pedicle. Ileocecal, ascending, and transverse colonic segments rely on a combination of superior mesenteric branches (ileocolic and right and middle colic arteries). See the image below.

Ileocecal urinary diversion using a plicated effer Ileocecal urinary diversion using a plicated efferent limb and catheterization; ureters are anastomosed into the bowel wall. Courtesy of Karl Kreder, MD.

Gastric segments are not used commonly for urinary diversion, although they remain popular for bladder augmentation.

For more information about the relevant anatomy, see Arterial Supply Anatomy, Colon Anatomy, and Bladder Anatomy.

Contraindications

The major contraindications to urinary diversion are bowel-type specific. Because of refractory metabolic abnormalities, jejunal segments should be used only in the absence of another acceptable type of bowel segment. Bowel injured by radiation should not be used for diversion. Patients with poor renal function, severe metabolic abnormalities, and significant proteinuria should not undergo diversion with continent reservoirs. Additionally, patients who lack motivation or are unable to catheterize a continent reservoir should not undergo diversion in this manner.

Because of the potential complications of a continent reservoir versus a noncontinent diversion, the urologist must be aware of the following specific contraindications prior to performing continent diversion:

  • Elderly age and spinal cord injuries associated with poor hand coordination are absolute contraindications for continent urinary diversion (including neobladder) because of the need for intermittent catheterization and the potential for catastrophic complications should these individuals fail to do so.

  • Bowel abnormalities such as Crohn disease, severe irritable bowel syndrome, fat malabsorption, and, potentially, ulcerative colitis preclude the surgeon from taking long segments of bowel.

  • Patients with a preoperative creatinine clearance of less than 60 mL/min should not undergo continent urinary diversion.

  • Those with a prior history of high-dose radiotherapy to the abdomen and/or pelvis should not have long lengths of small bowel used.

 

Workup

Laboratory Studies

Prior to urinary diversion, assessment of the patient's renal function is important. Most consider a minimum creatinine clearance of 60 mL/min necessary prior to performing continent diversion. A minimum of renal function is necessary because of the increased renal demand created by continent urinary diversion. Because of the increased contact time of urine with bowel segments, previously eliminated renal products are reabsorbed and must again be reexcreted.

Laboratory studies for patients with urinary diversion should be primarily directed toward excluding infection and assessing metabolic status, specifically metabolic acidosis because of concerns discussed in Pathophysiology. The following laboratory studies are suggested:

  • Arterial blood gas (if significant metabolic acidosis is expected)

  • Acid-base disturbance graph

  • Acid-base nomogram (may be found at via the National Center of Emergency Medicine Informatics at www.ncemi.org/etools/datafiles/acid-base_disturbance_graph.gif)

  • Complete blood cell count

  • Urinalysis and urine culture (if indicated)

  • Electrolytes, BUN, and creatinine

Imaging Studies

Ultrasonography is as follows:

  • Ultrasonography is a desirable method for imaging the upper urinary tracts because it requires no nephrotoxic agents.

  • Ultrasonography is most useful if findings are completely normal or if no change from prior multiple studies is demonstrated upon comparison.

  • Keep in mind that the appearance of hydronephrosis or hydroureteronephrosis does not always indicate obstruction. Surgeons commonly perform "nonrefluxing" ureteral anastomoses, which may result in an ultrasonographic image similar to that of an obstruction. One must consider if a "physiologic" antegrade study is indicated in conjunction with ultrasonography to definitively rule out obstruction.

  • Mild-to-moderate hydronephrosis in a patient with urinary diversion is not unusual, especially with a noncontinent conduit.

  • Remember that ultrasonography offers no information on the physiologic drainage of the urinary system.

Intravenous pyelography is as follows:

  • Most urologists are comfortable with the anatomical information obtained from an intravenous pyelography (IVP). Depending on the evaluating physician's preference, IVP is an excellent method of imaging the integrity and drainage of the upper urinary system.

  • The major drawback of this test is with a patient who is either allergic to intravenous contrast or is azotemic; however, in the absence of these two limitations, this is the study of choice for evaluating a patient for a urinary diversion procedure.

Nuclear scan is as follows:

  • Mercaptotriglycylglycine or diethylenetriamine pentaacetic acid is an excellent imaging agent for assessing renal function and drainage.

  • Drainage is better assessed with the addition of a Lasix injection after accumulation of tracer in the collecting systems.

  • The main drawback to nuclear imaging is the lack of information obtained regarding the precise location of obstruction or integrity of the urinary tract.

CT scanning is as follows:

  • Noncontrast CT scanning is most useful for demonstrating the presence of urinary calculi; if absent, performing a contrast-enhanced study alone or after noncontrast images is probably more useful for assessing drainage, function, and integrity.

  • CT scanning is extremely valuable for assessing a ruptured continent urinary reservoir or for determining the presence of fistulous communication of the urinary tract with the gastrointestinal or genital tracts.

MRI is as follows:

  • MRI is rarely indicated in an evaluation for urinary diversion. The most likely indication is to rule out recurrent cancer in a patient who has equivocal CT scan findings.

  • The other potential use for MRI is using gadolinium for imaging the drainage of a tract in a patient who is azotemic or allergic to intravenous contrast.

Cystography is as follows:

  • Distension of the continent reservoir with contrast is indicated when the patient is thought to have a ruptured segment. The reservoir must be assessed in at least two views, and the conduit must be adequately distended.

  • Redundant folds of bowel are not uncommon after a continent diversion has been fashioned. With this in mind, ensuring that those redundant folds are adequately distended is important for excluding rupture. A good rule of thumb is to ask the patient how much urine is normally obtained with each void or catheterization.

  • Cystography to rule out a rupture is best performed under real-time imaging, thereby allowing the reservoir to be monitored throughout the entire distension phase.

Other Tests

Urodynamic studies are as follows:

  • Urodynamic studies of continent bowel segments have been performed and reported in the medical literature.

  • Few clinical indications exist for urodynamic studies, with the exception of treating a patient with a continent urinary diversion and unrelenting incontinence.

Diagnostic Procedures

To determine the etiology for which urinary diversion is required, CT scanning, MRI, ultrasonography, IVP, and urodynamic studies play specific roles in helping determine the presence of malignancy, urinary tract obstruction, or urine storage abnormalities. All of these conditions may be harmful to the patient's future renal function.

Histologic Findings

Abnormal histologic findings are uncommon in diversion procedures because the pathologic bladder specimen is removed. Rarely, a biopsy is performed on the intestinal segments that have replaced the bladder. For further information on the histopathologic findings of bladder tumors, refer to Bladder Cancer.

 

Treatment

Medical Therapy

The treatment of urinary diversion is usually limited to the management of complications. These patients have unique problems that require the involvement of the surgeon who has been responsible for the patient's care prior to the date complications occurred.

Initially, the treating physician should focus on the date the patient had the diversion and the type of diversion performed, including the type of bowel segment used. Knowing the chronicity of the problem helps the treating physician stratify the patient as having early or late complications.

Early complications

These complications are best managed by consulting the surgeon who performed the diversion. Most commonly, the treatment is intravenous hydration and possible nasogastric tube placement guided by abdominal radiography and laboratory studies, including metabolic profile, complete blood cell count, urinalysis, and urine culture, if indicated.

If the integrity of the ureteral-bowel anastomosis is suggested to have been compromised, consider performing further imaging studies using ultrasonography, IVP, or nuclear renal scan.

Use ultrasonography judiciously as a diagnostic study because the presence of hydronephrosis does not necessarily indicate obstruction. Some degree of baseline hydronephrosis is not uncommon in patients with refluxing ureteral anastomoses.

Special attention must be given to patients with continent diversion, abdominal distension, and abdominal pain. One of the most catastrophic complications of continent diversion is reservoir rupture and bacterial peritonitis. The examining physician must maintain a low threshold for consulting a urologist and/or performing contrast-enhanced CT scanning of the abdomen and pelvis.

If urinary reservoir rupture goes undiagnosed and untreated, the outcome can be fatal. If a ruptured reservoir is diagnosed, administer broad-spectrum intravenous antibiotics and consult with a surgeon for urgent repair, if indicated. Reservoir rupture may be either an early or late complication of diversion. Particular attention must be given to patients with continent diversion after prior pelvic irradiation because these patients are at a high risk for reservoir rupture.

A continent catheterizable reservoir (ie, the urethra is not attached to the pouch) that is unable to catheterize via the efferent limb is a medical emergency. Ultrasound-guided percutaneous drainage may be required. Blind percutaneous drainage is discouraged because of the risk of injury to the mesenteric vascular pedicle that supplies the reservoir.

Urinoma may be treated with percutaneous drainage and/or stenting of the appropriate urinary segment in an effort to aid in closure of the abnormal communication.

Late complications

Urinary obstruction is best treated in the short term with percutaneous drainage or consultation with a urologist and retrograde drainage.

Prevention is the most effective treatment for vitamin B-12 deficiency. Strongly consider periodic parenteral replacement in patients with a urinary diversion in which ileum was used.

Electrolyte abnormalities are best treated in the short term with intravenous hydration and acidosis correction. The patient should receive lifelong supplementation with oral potassium and/or sodium citrate. Chlorpromazine or nicotinic acid may be given to patients in whom sodium loading may be dangerous.

Administer sodium chloride and thiazide diuretics (the potassium-wasting effect is desirable) to patients with jejunal conduit syndrome.

Diagnosing and treating concomitant pyelonephritis, obstruction, or urinary stasis is important in a patient with metabolic abnormalities; otherwise, the patient is sure to be refractory to treatment.

Secretory diarrhea is initially treated with cholestyramine (4 g PO bid) in an attempt to decrease colonic exposure and to free bile salts. Dietary fat restrictions are recommended for patients with significant steatorrhea (ie, >20 g/d).

Osmotic diarrhea is treated by slowing bowel motility with oral agents (eg, loperamide, diphenoxylate, difenoxin) to decrease transit time.

Surgical Therapy

Urinary diversion is typically performed after radical anterior pelvic exenteration; therefore, the typical patient undergoes surgery for several hours before the diversion is started. Attention must be given to the patient's preoperative state of health and ability to tolerate a potentially long surgical procedure. The surgeon performing the continent urinary diversion must carefully select the patient with this in mind.[5]  Most surgeons do not perform continent urinary diversions as rapidly as they perform noncontinent urinary diversions. See the images depicted below.

Close-up photograph of continent urinary diversion Close-up photograph of continent urinary diversion using ileum.
Noncontinent urinary diversion with ileum. Courtes Noncontinent urinary diversion with ileum. Courtesy of Karl Kreder, MD.

Candidates for urinary diversion due to neurologic dysfunction often do not have normal hand motor skills. Preoperatively, this condition must be evaluated carefully. Many patients with spinal cord injuries are excellent candidates for continent catheterizable diversions. For these patients to possess the skill to catheterize their own stomas and to rely on no one else to do so is paramount.

Preoperative Details

Preoperatively, ensure that the patient has undergone a full mechanical and antibiotic bowel preparation. If large-bowel segments are to be used, an air-contrast barium enema is recommended to rule out significant diverticulosis or other conditions that may exclude large bowel for use in urinary diversion.

Inquire about prior abdominal or pelvic radiotherapy, which suggests that the use of small-bowel segments is not appropriate, unless several years have passed since the patient received radiotherapy and the small-bowel segments appear grossly normal at the time of diversion.

Discuss several options of urinary diversion with each patient preoperatively. This discussion allows the freedom to exercise intraoperative decisions that suit the technical demands of each individual case.

Intraoperative Details

The surgeon should be very familiar with the intended procedure. Occasionally, altering the original plan and performing an alternative type of diversion secondary to individual patient anatomy is necessary.

No matter what type of diversion is planned, basic principles of abdominal surgery apply. Thoroughly irrigate the bowel contents after isolating the limb that will be used for diversion. The bowel reanastomosis should be widely patent and should be performed along the antimesenteric segments.

Debate exists regarding which type of ureteral anastomosis should be performed. Each type has its merits and disadvantages. The Wallace anastomosis allows for widely patent ureteral orifices, which are less likely to become obstructed. This procedure also allows for reflux of urine, which theoretically may predispose patients to long-term reflux nephropathy.

A nonrefluxing anastomosis significantly diminishes the risk of reflux nephropathy; however, it is also more prone to stricture and obstruction, which ultimately may lead to reoperation and repair.

To reduce urinary reflux, the authors prefer the Wallace type of anastomosis with a properistaltic segment of nondetubularized ileum.

Detubularizing continent reservoirs and reconstructing them in a more spherical shape is of paramount importance. This procedure allows for greater capacity and, most importantly, for reduced storage pressure.

In the case of neobladder construction, test the limb that will be isolated for diversion for mesenteric mobility prior to disrupting bowel continuity. Traction on stay sutures in the bowel segment allows the surgeon to determine whether placing the intended neobladder in the pelvis for the urethral anastomosis will be difficult. If difficulty is experienced, the surgeon may counter-incise the mesenteric peritoneum, mobilize the mesenteric pedicle to the root, and, in extreme cases, re-flex the operating table to decrease the distance between the pubic symphysis and the umbilicus.

Stents are recommended to bridge the ureteral anastomosis. When a neobladder is constructed, a urethral Foley catheter and suprapubic tube are left in place. When a continent catheterizable reservoir is constructed, a stenting catheter is left in place in the efferent limb and a suprapubic tube is placed through a separate portion of the reservoir and brought out through a stab incision in the skin. Noncontinent diversion is drained by ureteral stents only.

Postoperative Details

The length of time drainage tubes should stay in place varies according to individual practice. The authors prefer to stent the ureteral anastomosis for 2 weeks. The urethral Foley catheter is left in place for 2 weeks before removal. The suprapubic tube is then clamped and the reservoir, cycled with postvoid residuals, is checked. At the third postoperative week, the suprapubic tube is removed. Typically, an IVP is performed at 6 weeks postoperatively; renal ultrasonography is performed if the patient is allergic to intravenous contrast agents.

Complications

Early complications

These include postoperative ileus or bowel obstruction, which, as a group, is more common in continent diversions. Other early complications may include ureter-bowel anastomotic leak, acute pyelonephritis, and urinoma.

Late complications

Metabolic disturbances may result from the interaction of urine with the absorptive surface of the bowel used for the procedure.

Complications due to technical error and/or patient healing factors manifest most often as ischemic strictures. Technical errors that lead to stricture are caused by tension at the anastomotic site, inadvertent ligation of the vascular supply to the graft, and overzealous ureteral mobilization. In addition to avoiding excessive ureteral mobilization, surgeons must use electrocautery judiciously in their surgical dissection.

Patient comorbidities (eg, peripheral vascular disease, chronic obstructive pulmonary disease, infection) also contribute to altered healing and probably increase the overall incidence of complications. Unique metabolic derangements may occur because of urine contact with the absorptive surface area of the bowel mucosa.

Jejunal segments

Jejunal segments pose the most medically challenging metabolic abnormality with regard to urinary diversion. The decreased number of tight mucosal junctions allows for more water and electrolyte loss. Dehydration results in aldosterone secretion and urine delivery to the jejunal segment that is low in sodium and has an elevated potassium concentration. The jejunum responds by absorbing more potassium and exchanging sodium and water, exacerbating the dehydration and resulting in further aldosterone production. Aldosterone production perpetuates a cycle that is extremely refractory to treatment. The net effect in 27% of patients is a hyperkalemic, hyponatremic, hypochloremic metabolic acidosis, known as the jejunal conduit syndrome.

Ileal and colonic segments

Patients in whom ileal and colonic segments were used may develop hyperchloremic metabolic acidosis, which is likely caused by increased ammonium and chloride absorption by the bowel segment from the urine. Because of the poor absorptive capacity of colonic segments, these patients tend to develop hypokalemia more often than those in whom small-bowel segments were used. Patients with sepsis or decreased hepatic functional reserve who develop ammonia hyperabsorption by the bowel segment are at risk for hyperammonemia and encephalopathy.

Continent reservoirs

Increased bowel surface area or contact time with urine results in greater solute reabsorption and more pronounced abnormalities. Patients with continent reservoirs, which have both a greater surface area for absorption and prolonged contact times with urine, have a higher incidence of metabolic abnormalities. Additionally, creatinine is not a good measure of the glomerular filtration rate (GFR) in a patient who received a continent diversion. Varying amounts of urinary creatinine are reabsorbed by the bowel segment used to store urine; therefore, elevated serum levels of creatinine may not accurately predict the GFR.

Vitamin B-12 deficiency

Vitamin B-12 is an essential nutrient that cannot be synthesized by humans. The human liver is the major site of vitamin B-12 storage, and most stores can last approximately 3 years without replacement. The terminal ileum is the exclusive site of vitamin B-12 absorption in humans. Most urinary diversions in which ileum is used are performed in a way to compensate for the physiology of vitamin B-12 absorption; however, more than 50 cm of resection appears to be the critical length at which abnormal B-12 absorption may be expected.

With the addition of intrinsic factor, Pannek et al demonstrated that 20 of 25 (80%) patients with more than 50 cm of ileum who underwent resection for continent diversion demonstrated abnormal Schilling test results.[6] Patients with shorter limbs of ileum are not immune to vitamin B-12 deficiency and/or megaloblastic anemia; symptoms may take longer to manifest. Long-term follow-up studies in patients with shorter ileal segments demonstrate a 25-28% incidence of complications from vitamin B-12 deficiency. Patients in whom more than 50 cm ileum is resected are at increased risk for vitamin B-12 deficiency, which usually does not become clinically apparent for at least 2 years.

Table. Metabolic Disturbances Associated With Diversion (Open Table in a new window)

Bowel

Segment

Sodium (Serum)

Potassium (Serum)

Chloride (Serum)

Bicarbonate (Serum)

Clinical Presentation

Comments

Jejunum

Low

Elevated

Low

Low

Lethargy, vomiting, severe dehydration, weakness

Severe and refractory hyperkalemia with lack of efficacy of aldosterone; avoid using this bowel segment for diversion

Ileum

Low/Normal

Normal

Elevated

Low

Anorexia, weight loss, polydipsia, fatigue

Must encourage oral salt replacement and hydration; ileum preferred segment for diversion

Colon

Rupture of reservoir

One of the most devastating complications is rupture of the reservoir, which is most common in continent diversions. Hypercontinence of the catheterizable reservoir often leads to an elevated storage pressure and results in rupture. A less common etiology is partial herniation or volvulus of a noncontinent conduit, resulting in rupture of the proximal strangulated portion. Bacterial peritonitis invariably results when a bowel segment used for diversion ruptures. This condition is a surgical emergency that requires exploration, repair, and broad-spectrum intravenous antibiotics; therefore, a patient with a continent diversion and abdominal pain should be presumed to have a ruptured reservoir until proven otherwise. The risk of bacterial peritonitis and increased morbidity should prompt consultation with a urologist early in patient care.

Other complications

Note the following:

  • Secretory and/or osmotic diarrhea

  • Stomal stenosis, dermatitis, prolapse, retraction, and parastomal hernias (incidence, 15-40%)

  • Poor drainage of conduit or reservoir

  • Retention in the continent reservoir

  • Volvulus and retention in conduit (rare)[7]

  • Urinary lithiasis (especially in patients with secretory diarrhea and chronic dehydration)

  • Recurrent symptomatic infections

  • Ureterosigmoidostomy - Adenocarcinoma, urosepsis, ureteral stenosis, and/or hydronephrosis

Outcome and Prognosis

Using continent reservoirs as the primary means of diversion has gained popularity since the techniques have become more refined. Patients receiving continent diversion instead of noncontinent stomas perceive themselves as having a better body image and an improved quality of life. Recent reports do not demonstrate any adverse effects on prognosis or long-term survival for patients with continent versus noncontinent diversion.

Patients with recurrent cancer do not demonstrate any difference in the occurrence of complications with regard to the type of urinary diversion used; therefore, when properly performed, either form of diversion can allow virtually equivalent outcomes and good prognosis in properly selected patients.

Authors of a study of 65 patients who underwent urostomy administered a telephone questionnaire asking about stomal care and quality of life. Results showed that having questions answered before surgery, better bag replacement training, and early stomal care skill were associated with better long-term self-stomal care. Significantly more women than men self-managed their urostomy (85% vs. 44%) and self-management was associated with an improved quality of life.[8]

Future and Controversies

Cellular matrix grafts will be used as a substitute for abnormal tissue and/or to completely replace the abnormal bladder or urethra.

Cystectomy and female sexual dysfunction will become a bigger issue, and more attention will be paid to vaginal-sparing and nerve-sparing cystectomy.

Orthotopic diversion in females is gaining greater acceptance and now has fewer contraindications with regard to bladder replacement after cystectomy for malignancy.

 

Questions & Answers

Overview

When is urinary diversion performed?

What is the historical evolution of urinary diversion procedures?

What is noncontinent urinary diversion?

What is continent urinary diversion?

What is the prevalence of bladder cancer?

What are the most common indications for urinary system diversion?

What is the pathophysiology of urinary diversion?

What are the signs and symptoms of complications of urinary diversion?

What is the goal of urinary diversion in patients with spinal abnormalities?

Which bladder conditions are inherently dangerous and require a urinary diversion procedure?

What are the malignant indications for urinary diversion?

What are the neurogenic indications for a urinary diversion procedure?

Which benign conditions may require treatment with urinary diversion?

What is the anatomy of the bowel blood supply relevant to urinary diversion?

What are the contraindications for urinary diversion?

Workup

How is renal function assessed prior to urinary diversions?

What is the role of lab tests in the preoperative workup of urinary diversions?

What is the role of ultrasonography in the preoperative workup of urinary diversions?

What is the role of IV pyelography in the preoperative workup of urinary diversions?

What is the role of nuclear scan in urinary diversions?

What is the role of CT scanning in the preoperative workup of urinary diversions?

What is the role of MRI in the preoperative workup of urinary diversions?

What is the role of cystography in the preoperative workup of urinary diversions?

What is the role of urodynamic studies in the preoperative workup of urinary diversions?

How is the diagnosis of the condition requiring urinary diversion established?

What is the role of biopsy in urinary diversion procedures?

Treatment

What is included in the long-term care following a urinary diversion procedure?

How are the early complications of a urinary diversion treated?

How are the late complications of a urinary diversion treated?

How are candidates for urinary diversion selected?

What is included in preoperative care for urinary diversions?

How is a urinary diversion procedure performed?

What is included in the postoperative care following a urinary diversions procedure?

What are the possible early complications of a urinary diversion procedure?

What are the possible late complications of a urinary diversion procedure?

What causes jejunal conduit syndrome following a urinary diversion procedure?

What are the possible complications of a urinary diversion procedure using ileal and colonic segments?

Which factors increase the risk for metabolic abnormalities following a urinary diversion procedure?

What causes vitamin B-12 deficiency following a urinary diversion procedure?

What causes the rupture of reservoir following a urinary diversion procedure and how is it treated?

What are possible complications of urinary diversion procedures?

What is the prognosis following a urinary diversion procedure?

What is the future of urinary diversion procedures?