22.2.2.2 Continent Pouches and Bladder Augmentation

There were attempts by the turn of the century to use the bowel as a reservoir for urine. Bricker, Eiseman, Gilchrist, and Merricks [13–15] developed a technique that was claimed to give a capacious reservoir with a continent ileal stoma which could be emptied by periodic intermittent self‐catheterization (Figure 22.8). Couvelaire was critical of the method ‘Elle n’a rien d’une vessie, ni la continence, ni la miction’ [16]. Nor was it free from the complications of acidosis, ascending infection, and calculus formation.

More recently, a continent pouch is fashioned from about 60 cm of detubularised ileum rather than colon but employs the same principles. The ureters are anastomosed to the pouch with an anti‐reflux submucosal tunnel. A catheterisable stoma is brought out in the right iliac fossa.

In 1980 Mitrofanoff first described a continent supravesical catheterisable channel, using appendix on vascular pedicle [17]. In patients who have either lost an appendix at operation or do not have suitable lumen or length, alternatives have been used including small bowel [18, 19], ureter, Fallopian tube, colon, vas deferens, or even stomach [20–24].

The earliest attempts to enlarge the bladder with bowel were performed for bladders that had undergone contracture from tuberculosis or interstitial cystitis. Different segments of intestine were used, including colon, small intestine, and caecum (Figure 22.9). Spontaneous contractions of the bowel, especially the caecum, would result in incontinence of urine especially at night, but a more serious consequence of these uninhibited contractions was that they generated such a high pressure that there would be ureteric reflux and obstructive nephropathy.

These could be avoided if the bowel were ‘detubularised’ (i.e. opened out and sewn into the bladder as a flat patch). The uncoordinated bowel contractions would not generate any pressure; indeed, such a patch could be used in ‘clam cystoplasty’ to overcome deliberately raised bladder pressure in patients with vesical detrusor instability (Figure 22.10) [25–28].

As a result of this discovery, it became possible to devise a new kind of pouch or bladder enlargement with a very low pressure – so low indeed that it would not take much pressure on the outlet to maintain continence (Figure 22.11). Continence was usually at the expense of needing self‐catheterization and occasional spontaneous rupture [29].

Although Kock had first developed this pouch as a faecal reservoir for patients undergoing colectomy for ulcerative colitis, the idea was quickly adapted as a urinary reservoir. At first, the stoma was led out on the skin, later, it was anastomosed to the urethra as a true substitute for the bladder [30]. Because only a very low pressure was needed to keep in the urine, one could make use of an artificial sphincter, a loop of ileum, plicated ileum, or the appendix.

The ingenuity of its enthusiasts knew no bounds, and every conceivable permutation and combination of every part of the gastrointestinal tract was used to provide low‐pressure continent substitutes for the bladder (Figure 22.12) [31–34]. The multiplicity of these techniques and their innumerable modifications shows that none of them are yet perfect. Preoperative radiation to the bowel rules them out.

The two problems that remain a challenge are how to prevent reflux up the ureters and how to maintain continence. In the Kock pouch, reflux from the reservoir to the ureters is prevented by an ileal intussusceptum which forms a long nipple‐like valve. Continence of urine is achieved by a second intussusceptum valve on the efferent limb of ileum.

In a Camey technique, reflux is prevented by a submucosal tunnel similar to the classical Leadbetter valve in ureterocolic anastomosis (Figure 22.13) [35]. Mitrofanoff [34, 36] uses the appendix, where present, as a long narrow stoma, joining it to the skin or the urethra. At the umbilicus, it is invisible [37]. Others use plicated ileum to provide continence [38].

Complications of continent pouches [39–41] include:

• Mortality
  
• Small bowel obstruction
  
• Ischaemic necrosis of channel
  
• Peristomal abscess
  
• Stones
  
• Renal impairment
  
• Catheterisation difficulties
  
• Revision rate
  
• Stenosis
  
• Prolapse
  
• Reservoir rupture
  
• UTIs
  
• Metabolic disorders
  
• Malignancy

As mentioned previously, the choice of continent or conduit urinary diversions is based on a number of factors, but there are a number of studies which have reported the rate of complications of either type in the early postoperative period or in the long term. The studies with their number of patients, duration of follow up, and rate complications are tabulated in Table 22.6.

22.2.2.3 Natural Evacuation Urinary Diversion

22.2.2.3.1 Ureterosigmoidostomy

The first type of urinary diversion applied in 1852 by Simon had significant morbidities and mortality due to obstruction and sepsis. Innumerable techniques were devised for performing the ureterosigmoidostomy, but it was not until a direct elliptical mucosal anastomosis was combined with an anti‐reflux tunnel that the ascending infection complication was reduced, but remained significant. However, metabolic complications were significant. Physiologists had long been aware that if enough urine was absorbed by the intestine, it could eventually lead to renal tubular damage [42, 43], but the complication was thought to be very rare [44, 45]. Then, in 1950 Ferris and Odel published their long‐term follow‐up of 124 patients and found that no fewer than 62% had developed severe acidosis [46].

The biochemical changes were due to two factors: first and foremost was absorption of urine. Since normal urine is acidotic to the plasma by one‐third too much chloride, this absorption at a milliequivalent for milliequivalent rate can cause hypochloraemia, and the real problem is how much absorption occurs [47]. The second factor was renal function. If renal tubular function was perfect, it could cope with the acidosis. But when continued absorption of urine or damage from ascending infection and obstruction began to impair tubular function, acidosis would appear. This explained why it took so long for acidosis to develop in patients who started off with good kidneys [48].

Once the hazards of acidosis were appreciated, surgeons welcomed other alternatives to ureterosigmoidostomy. Nevertheless, the method still has a place (e.g. when the patient has a good anal control, good renal function, and a relatively short life expectancy) [49]. The Leadbetter tunnelled anti‐reflux technique reduced infection rates; however, high intrarectal pressures led to persistent infection as well as incontinence (Figure 22.14). The Mansoura and Mainz II techniques were devised to reduce intrarectal pressures.

22.2.2.3.2 The Mansoura Diversion

In Egypt as well as many countries where the poor and low socioeconomic uneducated class are prevalent, incontinence means social ostracism, and adhesive appliances are expensive and unreliable in the hot climate. Ghoneim, working with Kock, devised an ingenious modification of a historical urinary diversion technique the Mauclaire’s operation, which offers the patient a capacious urinary reservoir, prevents reflux of urine even in ureters that have been damaged by bilharziasis, and employs an intussusception valve which keeps the urine in the rectum and out of the rest of the colon (so it limits the absorbent surface area; Figure 22.15). The sigmoid colon is intussuscepted to prevent reflux and Kock ureteric anastomosis fashioned, an ileal augmentation of the sigmoid reduces intraluminal pressures.