Chapter 25. Urinary Diversion & Bladder Substitutions

Selected patients with lower urinary tract cancers or severe functional or anatomic abnormalities of the bladder may require urinary diversion. Although this can be accomplished by establishing direct contact between the urinary tract and the skin surface, it is most often performed by incorporating various intestinal segments into the urinary tract. Virtually every segment of the gastrointestinal tract has been used to create urinary reservoirs or conduits. No single technique is ideal for all patients and clinical situations. A decision is based on a patient's underlying disease and its method of treatment as well as on renal function, individual anatomy, and personal preference. An ideal method of urinary diversion would most closely approximate the normal bladder: it would be nonrefluxing, low pressure, continent, and nonabsorptive.

Individual methods of urinary diversion can be categorized in various ways, such as (1) by the segment of intestine used and (2) by whether the method provides complete continence or simply acts as a conduit carrying urine from the renal pelvis or ureter to the skin, where the urine is collected in an appliance attached to the skin surface. Continent forms of urinary diversion can be categorized further according to whether they are attached to the urethra (ie, as a bladder substitute) or are placed in the abdomen and rely on another mechanism for continence (continent urinary reservoir).

All candidates for urinary diversion or bladder substitution should undergo careful preoperative counseling and preparation, including a detailed discussion of the objectives and potential complications of each method. Any potential impact of a procedure on sexual function, body image, and lifestyle should be discussed. Overall satisfaction of most patients undergoing urinary diversion appears to be high (Allareddy et al, 2006; Dutta et al, 2002; Fujisawa et al, 2000a; Hara et al, 2002). However, because they allow freedom from an external appliance, continent forms of urinary diversion, especially bladder substitution, may be of great psychological and functional benefit to well-selected patients (Bjerre, 1995; Okada et al, 1997). More recent data suggest that the differences in quality of life between continent and noncontinent diversion may not be as significant as previously expected (Gilbert et al, 2007).

A careful history taken from the patient should note any previous abdominal or pelvic surgery, irradiation, or systemic disease. A history of intestinal resection or irradiation, renal failure, diverticulitis, regional enteritis, or ulcerative colitis would be especially important to consider when selecting a method of urinary diversion or bladder substitution. A complete blood count and measurement of serum electrolytes, urea nitrogen, and creatinine should be performed. The upper urinary tract should be imaged with intravenous urography, ultrasound, or computed tomography to determine whether hydronephrosis, renal parenchymal scarring, or calculous disease exists. Contrast imaging of the small or large bowel or colonoscopy should be considered preoperatively for patients with a history of significant intestinal irradiation, occult bleeding, or other gastrointestinal diseases. Patients with benign bladder diseases—such as a reduced bladder capacity due to neurologic disorders or irradiation, bladder fistulas, or interstitial cystitis—are occasionally considered candidates for urinary diversion or bladder substitution to manage urinary incontinence; however, with such patients, careful evaluation of bladder function and anatomy is required, as adequate urinary function can often be restored by urinary tract reconstruction, pharmacologic manipulation, or intermittent catheterization.

Patients undergo a standard mechanical and oral antibiotic bowel cleansing program beginning 1 or 2 days before surgery. Recent data suggest that mechanical bowel preparation can be avoided in colon and rectal surgery without increased risk of postoperative infectious complications. It may actually contribute to postoperative ileus. Hence use of clear liquid diet without mechanical bowel preparation prior to surgery may be adequate (Slim et al, 2009). Administration of combined oral and intravenous antibiotics prior to bowel surgery is advised as it appears to reduce the risk of wound infections by as much as 75% (Nelson et al, 2009). Much of patients' dissatisfaction with urinary diversion can be attributed to poor stomal construction or siting (Fitzgerald et al, 1997). The patient should be preoperatively evaluated in the lying, sitting, and standing positions with their clothes on. The stoma should preferably be located above or below the belt line. The most common site for stoma placement is through the rectus abdominis muscle sheath to avoid the later development of a parastomal hernia. The ideal location is free of creases, folds, previous incisions, and in a location visible to the patient to ensure ability to care for stoma. In obese patients or patients with a short mesentery, the stoma should be placed closer to the level of the umbilicus or in the right upper quadrant.

Ileal Conduit

Ureteroileal urinary diversion is the most common method of urinary diversion in the United States. The conduit is constructed using a segment of ileum 18–20 cm long and located approximately 15–20 cm proximal to the ileocecal valve (Figure 25–1). Longer conduits may be required in obese patients, but a short segment minimizes the absorptive surface of the bowel in contact with urine. Once the appropriate length of bowel is selected and isolated, the mesentery is divided proximally and distally and individual mesenteric blood vessels are ligated. The bowel is divided, thus isolating the segment selected for conduit construction. The continuity of the small intestine is reestablished, with the anastomoses being above the plane of the conduit allowing for normal bowel function. The conduit is usually positioned in the right lower quadrant of the abdomen in an isoperistaltic direction. The posterior closed end of the conduit can be sewn with an absorbable suture to exclude the staple line and fixed to the posterior peritoneum or the sacral promontory to prevent volvulus of the conduit. The ureters are reimplanted individually in an end-to-side fashion or joined together (Wallace technique) and anastomosed in an end-to-end fashion, creating a refluxing ureteroileal anastomosis. Ureteral stents (7–8F, single-J, Silastic) are usually placed through the ureteral anastomosis and conduit and into the renal pelvis to facilitate urinary drainage while the anastomosis is healing.

The preselected stoma site is identified and a small circle of skin and underlying fat excised. The fascia is incised in a cruciate fashion. The end of the conduit is brought through the rectus abdominis muscle and anchored to the fascia, and the stoma is then formed. The stoma should protrude, without tension, approximately 1–1.5 in above the skin surface.

Jejunal Conduit

Jejunal conduit urinary diversion is used rarely and mainly in cases where other segments cannot be used due to significant ileal and colonic disease caused by previous irradiation or inflammatory bowel disease. Electrolyte disturbances are more common when the jejunum is used for conduit construction and hence this bowel segment is used only if none of the other intestinal segments can be used to fashion a conduit.

Colon Conduit

There are several advantages to using the large bowel in construction of urinary conduits: nonrefluxing ureterointestinal anastomoses are easily performed, possibly abrogating the deleterious effects of reflux on the upper urinary tracts (Richie and Skinner, 1975); stomal stenosis is uncommon because of the wide diameter of the large bowel; limited absorption of electrolytes occurs; and the blood supply to the transverse and sigmoid colon is abundant. Either the transverse or the sigmoid colon can be used, allowing for placement of the conduit high or low in the abdomen, depending on the integrity and condition of the ureters. Use of the transverse colon for conduit construction is especially well suited for patients who have received extensive pelvic irradiation or when the middle and distal ureters are absent.

The blood supply of the transverse colon is based on the middle colic artery. The greater omentum is separated from the superior surface of the transverse colon, and a segment of bowel, usually 15 cm in length, is selected for the conduit (Figure 25–2). Short mesenteric incisions are made, and the colon is divided proximally and distally. Once the conduit is isolated, bowel continuity is reestablished. The proximal end of the conduit is closed and fixed in the midline posteriorly. The ureters are brought through small incisions in the posterior peritoneum and reimplanted into the base of the conduit. The stoma may be positioned on either the patient's right or left side.

A sigmoid conduit is constructed in a similar manner. Great care should be taken to preserve the blood supply by carefully selecting a segment with a good blood supply and by making short mesenteric incisions. The conduit is positioned lateral to the reapproximated sigmoid colon. Ureteral reimplantation and stoma construction are completed.

The ureters can be reimplanted into the large intestine either in a nonrefluxing submucosal tunnel or in a refluxing end-to-side manner. A submucosal tunnel can be created by incising the tenia up to the mucosa of the large bowel for a distance of 3–4 cm. A “button” of mucosa is removed, and the ureter is anastomosed to the mucosa of the bowel. The muscularis of the tenia is reapproximated over the ureter to complete the tunnel (Figure 25–3).

General Considerations

Various procedures have been developed for construction of bladder substitutes or continent urinary reservoirs that preclude the need for an external urine collection appliance. Such reservoirs or bladder substitutes are composed of three segments: ureterointestinal (afferent limb) anastomosis, the reservoir itself, and the conduit carrying the urine from the reservoir to the surface (efferent continence mechanism). Bladder substitutes rely on the intact urethra and sphincter to provide outlet resistance and carry urine to the urethral meatus. In men and women whose urethrae are involved by cancer or are not functional owing to benign diseases, an efferent continence mechanism can be constructed with the ^appx or short segments of tapered, intussuscepted, or reimplanted intestine.

The decision to proceed with bladder replacement is dependent on the risk of urethral recurrence and the continence of the patient. Both men and women who have low risk of urethral recurrence and those who have intact external urinary sphincters should be considered for bladder replacement rather than construction of a continent urinary reservoir. The risk of urethral occurrence or recurrence in men who undergo radical cystectomy is 6.1–10.6%. Carcinoma in situ and tumor multifocality appear to be risk factors for prostatic urethral tumor involvement in men with bladder cancer (Nixon et al, 2002). Although prostatic urethral disease is a risk factor for urethral recurrence, recent evidence suggests that orthotopic diversion may be considered in those with only proximal prostatic urethral involvement and negative urethral margins at cystectomy (Iselin et al, 1997). Although orthotopic bladder replacement was once reserved for men, it is now commonly performed in women as well (Stein et al, 1997). Women with bladder cancer whose tumors are not located at the bladder neck and have a clear urethral margin at the time of cystectomy are candidates for this procedure. Approximately 66% of women undergoing radical cystectomy for the management of bladder cancer fall into this group (Stein et al, 1995, 1998a; Stenzl et al, 1995). Intraoperative inspection and frozen section assessment of the bladder neck limits the risk of urethral recurrence.

The bowel segments should be opened and refashioned (detubularized) to interrupt the normal high-pressure contractions of the intact intestine (Hinman, 1988). A large radius is preferred, as this results in a reservoir with a larger geometric capacity and lower pressure. Continent reservoirs and bladder substitutes may be made of small intestine, large intestine, or a combination of both. Even though bladder substitution is perceived by some as a more complex procedure, prior studies have demonstrated complication and reoperation rates similar to those of ileal conduit urinary diversion in the hands of experienced surgeons (Gburek et al, 1998; Parekh et al, 2000). Long-term results of bladder replacement demonstrate excellent functional outcomes (Abol-Enein and Ghoneim, 2001; Elmajian et al, 1996; Hautmann et al, 1999; Stein et al, 1997; Stenzl et al, 2001; Steven and Poulsen, 2000). Daytime continence can be expected in 87–100% of men and 82–100% of women. Nighttime continence is achieved in 86–94% of men and 72–82% of women. Nearly all men are able to void to completion, while approximately 25–50% of women require intermittent catheterization to completely empty the neobladder. It is beyond the scope of this chapter to review all techniques and minor modifications; instead, the most common techniques and the general principles of continent diversion are reviewed.

Ureterosigmoidostomy

The first direct anastomosis of the ureters into the intact colon was performed by Smith in 1878 (Smith, 1879). Peritonitis (from fecal spillage) and pyelonephritis (resulting from ascending infection and stricturing of the ureteral anastomosis) led initially to very high surgical mortality rates. Recognizing that ascending infection from the rectum into the kidney was a major problem, surgeons developed techniques to reimplant the ureters into the colon in an antirefluxing fashion. Since patients will retain large amounts of urine and fecal material simultaneously in the rectum, assurance of adequate rectal sphincter function is important preoperatively. Since ammonia may be absorbed across the bowel surface, patients with liver disease who may be at an increased risk of hyperammonemic encephalopathy should not undergo this procedure. Patients who have primary diseases of the colon or have received extensive pelvic irradiation should undergo alternative forms of diversion.

The ureters are identified at or below the common iliac arteries. The overlying peritoneum is incised and the ureters are mobilized carefully to preserve their blood supply. A site low in the sigmoid is selected for ureteral reimplantation. The ureters are reimplanted separately into the respective ipsilateral tenia coli, using the antirefluxing techniques described earlier. The peritoneum is sutured over the completed ureteral anastomosis (Figure 25–4).

One particularly worrisome complication of ureterosigmoidostomy is development of adenocarcinoma at the site where the ureters have been reimplanted into the large intestine. The incidence of anastomosis site adenocarcinoma is uncertain, but there seems to be a several thousandfold increase in its incidence in patients who have undergone ureterosigmoidostomy over individuals who have not undergone this type of surgery. The induction period varies but may be approximately 20 years; thus, the risk is especially high in young patients. Experimental studies have shown that the development of adenocarcinoma seems dependent on the presence of urine, feces, urothelium, and colonic epithelium in close approximation. All those who undergo ureterosigmoidostomy should be counseled to undergo yearly sigmoidoscopy starting 5 years after the procedure and at any time occult or gross gastrointestinal bleeding or a major change in bowel habits is noted.

Reservoirs Constructed of Small Intestine

Nils Kock was responsible for the early and ongoing development of a continent urinary reservoir fashioned entirely of small intestine (Kock et al, 1982; Nieh, 1997). This reservoir includes the construction of nipple valves as the proximal and distal ends of the reservoir to prevent ureteric reflux (proximally) and incontinence (distally). The Koch reservoir is no longer commonly used due to a high incidence of complications related to the nipple valves.

In an attempt to decrease the complication rate associated with the afferent intussuscepted antireflux nipple of the Kock ileal neobladder, Stein and colleagues (1998b) have described an innovative antireflux technique (Figure 25–5). This new reservoir, the T pouch, has several important advantages over the Kock ileal neobladder: (1) It requires a smaller segment of ileum to create the antireflux technique, (2) the serosal-lined antireflux mechanism eliminates the need for intussusception, (3) blood supply is better preserved, and (4) urine is not in contact with the implanted portion of the ileum.

Camey described a technique of bladder substitution whereby an intact segment of ileum was anastomosed directly to the urethra (Lilien and Camey, 1984). A 40-cm segment of ileum was isolated from the gastrointestinal tract, and its midpoint was anastomosed, without tension, directly to the urethra. The ureters were reimplanted into either end of the ileal segment in an antirefluxing fashion. However, failure to detubularize the ileal segment led to a high incidence of urinary incontinence compared with substitutes fashioned from detubularized small-bowel segments (Hautmann et al, 1999; Studer and Zingg, 1997). Forty- to sixty-centimeter segments of ileum can be detubularized and folded into U-, S-, or W-shaped reservoirs, which can be connected directly to the urethra (Figure 25–6). The ureters are reimplanted directly into a short segment of ileum at the proximal end of the bowel segment, isolated to fashion the diversion, which is not detubularized. End-to-side ureteric anastomosis into this isoperistaltic segment of ileum prevents reflux. With the Hautmann type of ileal neobladder (W configuration), nondetubularized segments of ileum can be left intact at either end of the W and the ureters individually implanted into each of these segments. This would make it easier to dissect the ureter if a nephroureterectomy is required at a later date for upper-tract tumor recurrence. The larger diameter and lower pressure of these reservoirs compared with those of nondetubularized bowel have led to better continence rates.

Reservoirs Constructed of Large Intestine

Various investigators have described using segments of the large intestine alone or combinations of large- and small-bowel segments to fashion urinary reservoirs (Bihrle, 1997; Lampel et al, 1996). Bladder substitutes have been constructed using detubularized bowel segments from the ileocecal region or sigmoid colon. Use of the ascending colon and terminal ileum to construct continent urinary reservoirs has gained great popularity. Cecum and ascending colon are detubularized and refashioned or augmented with the small intestine to provide for a spherical reservoir. The ureters are reimplanted in a nonrefluxing fashion (Figure 25–7). The reservoir can be anastomosed directly to the urethra. In women or in men who require a urethrectomy, a continent, catheterizable stoma can be fashioned of ^appx or tapered terminal ileum (Figure 25–8).

Postoperative Care

Postoperative care varies depending on the method of urinary diversion or bladder substitution. As with all patients who have undergone major abdominal surgery, early ambulation, use of intermittent compression stockings, and incentive spirometry may be used to prevent pulmonary emboli or respiratory complications. Nasogastric tubes are optional and can be used in patients with abdominal distension, nausea, and emesis. Serum electrolytes and creatinine should be monitored postoperatively for the development of metabolic abnormalities. If single J ureteral stents have been placed, they are usually removed sometime after postoperative day 5; double J stents may stay in place for up to 3 weeks in patients undergoing neobladders. Continent urinary reservoirs and bladder substitutes produce mucus. They should be irrigated regularly in the early postoperative period to prevent mucus accumulation. Mucus production decreases over time, and irrigation ultimately becomes unnecessary. Upper urinary tract surveillance for hydronephrosis should be performed on a regular basis using ultrasound or computed tomography. An initial assessment of the upper urinary tract is made in the early postoperative period; if upper urinary tract dilation is not found, the patient undergoes repeat imaging on a yearly basis or as dictated by surveillance protocols for the stage of bladder cancer.

Complications occurring after urinary diversion, bladder substitution, or continent urinary diversion are generally a product of surgical technique, the underlying disease process and its treatment, the age of the patient, and the length of follow-up (Carlin et al, 1997; Gburek et al, 1998). Early complications, which are uncommon (occurring in approximately 10–20% of patients), include excessive bleeding, intestinal obstruction/ileus, urinary extravasation, and infection. Late complications (10–20% of patients) include metabolic disorders, stomal problems (stenosis or hernia), pyelonephritis, and calculi. Rarely, spontaneous neobladder rupture may occur presumably due to overdistention or blunt abdominal trauma (Nippgen et al, 2001). Such patients usually present with peritonitis and acute abdominal pain. Perforation of continent cutaneous diversions can occur and can be related to vigorous catheterization.

Metabolic and Nutritional Disorders

Fluid, electrolyte, nutrient, and waste product excretion or absorption normally occurs across the intestinal wall. Metabolic abnormalities may occur when intestinal segments are interposed into the urinary tract. As pointed out previously, use of the jejunum may result in hyponatremic, hypochloremic, hyperkalemic metabolic acidosis in up to 40% of patients. The jejunum is unable to maintain large solute gradients, so large amounts of water and solute pass through the jejunal wall. Sodium and chloride are rapidly excreted into the conduit, and potassium is passively absorbed. Aldosterone is produced, resulting in reabsorption of hydrogen and excretion of potassium into the distal tubule of the kidney and consequent acidosis and movement of potassium from the body's intracellular stores. As water is lost into the conduit, extracellular fluid volume is reduced, as is the glomerular filtration rate. The renin–angiotensin system is activated which further stimulates aldosterone secretion. Urea may be absorbed from the jejunal lumen, which (with dehydration) contributes to azotemia. This syndrome is often characterized clinically by nausea, vomiting, anorexia, and muscle weakness.

The pathogenesis and nature of metabolic abnormalities occurring after incorporation of the ileum or colon into the urinary tract differ from those associated with jejunal conduits. When such segments are used, sodium and chloride are absorbed across the bowel surface. Chloride is absorbed in slight excess of sodium, resulting in a net loss of bicarbonate into the bowel lumen. Preexisting renal failure contributes to the development and severity of the disorder, as does a large bowel surface area and long contact time. Hyperchloremic acidosis is more common in patients who undergo ureterosigmoidostomy than in patients who undergo simple conduit construction using either the ileum or the colon, because of the larger surface area and longer contact time with urine associated with ureterosigmoidostomies. Hyperchloremic metabolic acidosis may manifest clinically as weakness, anorexia, vomiting, Kussmaul breathing, and coma. One potential long-term complication of chronic acidosis may be decreased bone calcium content and osteomalacia (Kawakita et al, 1996; McDougal et al, 1988).

Bile salts are important for fat digestion and uptake of vitamins A and D. Bile salt metabolism may be altered after ileal resection (Olofsson et al, 1998). Resection of small segments of the ileum may be associated with mild malabsorption and steatorrhea owing to increased concentrations of bile salts delivered to the colon. The increased concentration of such salts leads to decreased colonic absorption of water and electrolytes. Resection of large segments of ileum may reduce bile salt reabsorption to very low levels, leading to severe fat malabsorption. Bowel transit time may be reduced further by resection of the ileocecal valve. Cholestyramine may be used to treat secretory bile salt diarrhea. If diarrhea persists, addition of agents such as loperamide that decrease bowel motility and increase transit time may be effective. Cholelithiasis may be more common after ileal resections as well.

Vitamin B12 deficiency may occur as a result of either gastric or ileal resection (Fujisawa et al, 2000b; Terai et al, 1997). Because B12 stores are likely to last for years, its deficiency may not become apparent for several years after intestinal surgery. B12 deficiency results in megaloblastic anemia and peripheral nerve paresthesias. The levels of this vitamin can be assessed in patients after ileal or gastric resection. Alternatively, yearly replacement by injection of Vitamin B12 is adequate in those in whom deficiency is noted.

Stoma

A good deal of patients' dissatisfaction with urinary diversion can be attributed to stomal complications. Stoma construction is especially important in procedures in which a pouch must be worn. Careful stomal construction as outlined earlier is essential (Fitzgerald et al, 1997). Most peristomal skin problems can be avoided with adequate siting, good surgical technique coupled with regular follow-up with a nurse specialized in ostomy care and follow-up (Enterostomal Therapy Nurse; wound, ostomy, and continence nurse [WOCN]). Complications related to the stoma can be separated into (1) stomal complications: necrosis, stenosis, hernia, retraction, or prolapse and (2) peristomal complications: dermatitis related to fungal infections, contact allergic reactions, mechanical trauma, and contact dermatitis leading to alkaline encrustations from urine on the skin over time. They are often related, as a stenotic stoma may be difficult to pouch leading to chronic skin irritation. External stomal and peristomal complications rates range from 15% to 65% (Szymanski, 2010). The likelihood of stomal stenosis increases with time. Stomal stenosis can lead to conduit elongation and upper-tract obstruction. This condition can be diagnosed relatively easily by catheterizing the stoma and measuring the residual urine volume. It is corrected by revision of the stoma. Parastomal herniation tends to occur as a delayed complication in 5–28% of patients (Franks and Hrebinko, 2001; Symanski et al, 2010). One cause for this is the location of the stoma lateral to the rectus muscle, which eliminates the circumferential support provided by the muscle cuff around the stoma. The hernia typically tends to occur around the superolateral aspect of the stoma. Placing the stoma such that the conduit is traversing the rectus muscle may not always decrease the likelihood of parastomal hernia (Gray, 2005). Some degree of stomal bulge without a hernia is commonly noted in most patients with conduits. Repair of a stomal hernia requires reinforcing the rectus fascia with mesh, either intraperitoneally through the previous midline incision or through an incision lateral to the stoma. In some cases, it may be necessary to move the stoma to a new site, preferably to the contralateral side of the abdominal wall. Recurrence rates following hernia repair were high previously but have declined considerably to 0–7% in recent series (Franks and Hrebinko, 2001; Ho and Fawcett, 2004).

Skin irritation or infections are most common in procedures in which an appliance is worn and there is prolonged contact of the skin with urine. Some patients' skin may be sensitive to adhesive agents.

Stomal or skin problems are minimized by selecting an appropriate pouching system. Extended wear pouches provide better skin protection because of better adhesion and delayed moisture absorption (Colwell, 2005). The treatment of parastomal conditions is summarized in Table 25–1.

The most troublesome stomal complication of external urinary appliances is unexpected pouch leakage. This is often a result of improper application of the pouch but may be caused by poor stomal construction. With a properly constructed and located stoma, the choice of the pouch is relatively simple and is often determined by patient preference. Factors that must be taken into account when selecting a pouch include patient dexterity and preference, available resources, and stomal construction. Pouches have an adhesive skin barrier that attaches to the skin and a bag that collects urine. An opening is made in the middle of the skin barrier; this opening should be of a diameter just larger than the stoma to avoid erosion of the stoma or prolonged contact of the skin with urine, typically one-eighth of an inch on each side unless the stoma is retracted or at skin level then the opening may be more secure if there is one-fourth-inch clearance on each side to avoid undermining (Doughty, 2005).

Most patients favor using disposable urinary collection pouches. Disposable, one-piece pouches are single use. Two-piece systems allow the patient to remove the pouch, leaving the skin barrier intact. A larger collection device is often attached to the pouch at night.

Continence and Urinary Function

One of the common late complications of continent urinary diversion is urinary incontinence that can occur following both cutaneous diversion and in neobladders. Nighttime incontinence is particularly a problem with neobladders and can occur in about 20–50% of all patients (Lee et al, 2003; Meyer et al, 2004). Daytime incontinence is significantly lower and ranges from <10% to 33%. Reported continence rates are higher with the T pouch at around 87% (daytime) and 72% (nighttime) (Stein, 2004). The wide variations in reported continence rates stem from varying definitions of continence. Improvement in continence is observed with time and increasing neobladder capacity reaching 92% for daytime and 80% at nighttime by 2 years (Studer, 1996). Bladder capacity increases gradually and stabilizes to reach >450 cc and continence also improves over time in these patients (Permenis, 2004). Incomplete emptying can occur in a small percentage of patients requiring long-term self-catheterization. Women who undergo neobladder construction are especially at risk for hypercontinence, which can occur in 12% to as high as 60% of patients and must be counseled preoperatively in this regard (Stein et al, 2009; Stenzl et al, 2001). Day- and nighttime continence rates appear to be similar between male and female patients and the most common types of neobladders reconstruction (Studer vs Hautmann) (Lee et al, 2003; Stenzl et al, 2001). Sphincteric damage and low urethral resting pressures are believed to be the reasons for incontinence while urethral denervation, poor pouch contractility, and/or exaggerated acute angulation of the neobladder urethral junction are believed to be the reasons for hypercontinence and retention. Frequent bladder emptying, urethral collagen injection, artificial urinary sphincter placements, and urethral slings are all potential treatment options for incontinence while catheterization is the main therapy for urinary retention.

Pyelonephritis and Renal Deterioration

Pyelonephritis occurs in approximately 10% of patients who have undergone urinary diversion. Treatment is based on a properly collected urine sample for culture. A urine sample should not be collected from the pouch; rather, the pouch should be removed, the stoma cleansed with an antiseptic, and a catheter advanced gently through the stoma. If infection has occurred in a patient with a simple conduit, the volume of residual urine within the conduit should be recorded. Obstruction and stasis of urine within the reconstructed urinary tract are risk factors for the development of infection.

Although many patients with preexisting dilation of the upper urinary tract show improvement or resolution of the dilation after urinary diversion or bladder substitution, progressive renal deterioration as manifested by hydronephrosis or an increasing serum creatinine level (or both) occurs in some patients who undergo these procedures. The incidence of either complication increases after 10 years. The presence of hydronephrosis, particularly in patients with a conduit diversion, may indicate the presence of ureteric reflux or obstruction at the ureterovesical junction. A loopogram will help demonstrate if there is retrograde flow of contrast from conduit to the ureter and renal pelvis. In some situations, it may be necessary to obtain a radionuclide renal scan (MAG3) to determine if there is antegrade flow of urine from the kidney through the ureters. Pyelographic evidence of upper urinary tract deterioration has been noted in up to 50% of patients who have undergone urinary diversion at an early age. Recurrent upper urinary tract infection and high-pressure ureteral reflux and obstruction, usually in combination, contribute to the likelihood of renal deterioration. Upper-tract deterioration is less likely following ileal continent diversion. While a majority of kidneys will demonstrate mild dilation, 97% of patients show no change in renal parenchymal size and 100% show no change in serum creatinine 10–15 years following the Studer type of ileal neobladder (Perimenis, 2004).

Calculi

Calculi occur in approximately 8% of patients who undergo urinary diversion or bladder substitution (Cohen and Streem, 1994; Terai et al, 1996). Such patients have several risk factors for the development of various calculi. Nonabsorbable staples, mesh, or suture material used to construct conduits or reservoirs may act as a nidus for stone formation. Colonization in either conduits or reservoirs is common, whereas symptomatic infection is much rare. Certain bacteria can contribute to stone formation; some bacteria commonly found in the urinary tract, including Proteus, Klebsiella, and Pseudomonas species, produce urease, a urea-splitting enzyme that contributes to the formation of ammonia and carbon dioxide. Hydrolysis of these products results in an alkaline urine supersaturated with magnesium ammonium phosphate, calcium phosphate, and carbonate apatite crystals. Management of such infection-related stones requires stone removal, resolution of infection, and, often, use of adjunctive agents to complete stone dissolution.

The likelihood of stone formation is increased by the development of systemic acidosis. Prolonged contact of the urine with the intestinal surface facilitates the exchange of chloride for bicarbonate. Bicarbonate loss results in systemic acidosis and hypercalciuria. The combination of hypercalciuria and alkaline urine predisposes a patient to the development of calcium calculi. In addition, the terminal ileum is responsible for bile salt absorption; if this portion of the intestine is used for conduit or bladder reservoir construction, excess bile salts in the intestine may bind calcium and result in increased absorption of oxalate, which may lead to the development of oxalate-containing calculi. Hypocitraturia may also be a risk factor for stone disease in patients undergoing bladder replacement (Osther et al, 2000). Excess conduit length, urine stasis, and dehydration make the development of calculi more likely.

General

Colon Conduit

Continent Urinary Diversion and Bladder Substitution

Ureterosigmoidostomy

Complications

Ostomy Care