Types Of Urinary Diversion History

The earliest attempts at urinary diversion occurred in the mid-19th century. This idea was based on the observation that birds possessed a cloaca, through which both urine and feces were expelled. Improving surgical techniques culminated in the successful creation of the ureterosigmoidostomy in 1911, which was to become the most commonly employed form of urinary diversion for the next 40 yr (8). The operation had the advantages of being relatively easy to perform, and it allowed the patient to be continent via the anal sphincter. It became increasingly evident, however, that ureterosigmoidosto-mies had treacherous long-term complications. First, the anastomoses of the ureters to the intact fecal stream lead to unacceptably high rates of pyelonephritis and renal deterioration. Second, the exposure of urine to the entire length of the large bowel often created severe life-threatening metabolic acidosis. Finally, a high rate of adenocarcinomas was observed to occur near the uretero-intestinal anastomosis (8-11).

The problems associated with urterosigmoidostomy necessitated improvements in urinary diversions. Some surgeons came to prefer cutaneous ureterostomies, whereby the ureters were simply brought up to the skin as stomas. Intuitively, such an operation seemed sensible because it avoided many of the complications of ureterosigmoidos-tomy. In practice, however, cutaneous ureterostomies suffered from high rates of stomal stenosis. They are occasionally useful, however, as palliative procedures (9).

Ileal Conduit

The solution to the problems inherent to both ureterosigmoidostomies and cutaneous ureterostomies came in the early 1950s, when Bricker introduced the ileal conduit (12). The ileal conduit is incontinent and does not actually store urine, but its large "rosebud" stoma allows for proper ostomy appliance placement, and the end-to-side refluxing ureteral anastomosis is technically easy to perform (Fig. 1). Moreover, urinary absorption with a conduit device was minimized, averting the severe acidosis observed with ureterosigmoidostomies. Like all externally draining ostomies, the choice of stomal location is important for the purposes of appliance application and leak prevention.

Bricker's operation remains the gold standard for urinary diversions today. Conduits created from large bowel have also been used for urinary diversion, but they possess no significant advantage over those fashioned from ileum. Candidates for an ileal conduit include adult patients requiring cystectomy. The ileal conduit may also be a better operation for patients in whom postoperative pelvic radiation is anticipated, because it is typically placed outside of the radiation field. Recent studies have demonstrated that patients with ileal conduits adapt well to the operation, and may not necessarily report an inferior quality of life compared to patients who receive a continent diversion (13,14).

Continent Urinary Diversions

Gilchrist described a technique for the creation of continent urinary diversions shortly after the introduction of the ileal conduit (15). In this type of diversion, the ascending colon was utilized as a continent reservoir, whereas the ileocecal valve served as the continence mechanism. The operation was not widely embraced, but its basic principles served as the model for subsequent continent reservoirs. Renewed interest in continent diversions emerged in the 1970s and 1980s, however, in response to patient demands and the realization that the ileal conduit was not an acceptable diversion in the pediatric population.

The most commonly performed continent catherizable urinary diversion utilized in the United States today is the so-called Indiana pouch (16,17). Like Gilchrist's operation, this urinary diversion utilizes the ascending colon, ileocecal valve, and terminal ileum to create a continent reservoir. It differs from this procedure, however, in that the colonic segment is detubularized, and the ileocecal valve plicated to improve continence (Fig. 2). The short segment of terminal ileum is brought to the skin surface as a flush, catherizable stoma. In some cases, an efferent stomal limb may be constructed of appendix (the "Mitrofanoff principle") (18). This is particularly useful in children, whereby the appendiceal limb can be brought out inconspicuously through the umbilicus.

The rationale for bowel detubularization and reconfiguration is that a detubularized segment of bowel maximizes the volume for a given surface area. Furthermore, detubularized reservoirs maintain relatively constant pressures with increasing radius due to distension, following Laplace's law:

Reservoir pressure = Wall tension/ radius

In spite of adherence to these principles, however, reconfigured bowel still remains peristaltic to some degree, occasionally resulting in high-pressure contractions and incontinence. These reservoirs may initially possess a small capacity, but their volumes will increase over time as they are allowed to store urine.

Orthotopic Neobladders

Detubularized bowel reservoirs can also be utilized as orthotopic neobladders. A commonly utilized neobladder was designed by Studer et al. (19). This operation creates a reservoir from a 60-cm segment of terminal ileum, which is then anastomosed to the urethra. Neobladders from combined ileocecal segments and sigmoid colon may also be created (20-23).

Studer PouchBricker Conduit

Fig. 1. Construction of the ileal conduit. (Reprinted with permission: Shapiro E, Ileal conduit urinary diversion. In Marshall F, ed. Operative Urology. WB Saunders, Philadelphia, PA 1991.) (A) Segment of terminal ileum isolated with adequate mesenteric blood supply. (B) Ileal segment resected and ileal continuity reestablished. (C) Ureters anastomosis to ileum in end to side fashion. (D) Distal ileal end pulled through the abdominal wall. (E) Rosebud stoma created.

Fig. 1. Construction of the ileal conduit. (Reprinted with permission: Shapiro E, Ileal conduit urinary diversion. In Marshall F, ed. Operative Urology. WB Saunders, Philadelphia, PA 1991.) (A) Segment of terminal ileum isolated with adequate mesenteric blood supply. (B) Ileal segment resected and ileal continuity reestablished. (C) Ureters anastomosis to ileum in end to side fashion. (D) Distal ileal end pulled through the abdominal wall. (E) Rosebud stoma created.

Indiana Pouch Urinary Diversion

Fig. 2. Construction of an Indiana Pouch with catherizable stoma. (A) Segment of ascending colon and terminal ileum resected with preservation of blood supply. (B) Ureters anastomosed to cecal segment and terminal ileum acting as efferent limb for catheterization. (C) Cecal segment split and pulled over to form a pouch to minimize pouch pressure. (D) Efferent limb brought out for catheterization.

Fig. 2. Construction of an Indiana Pouch with catherizable stoma. (A) Segment of ascending colon and terminal ileum resected with preservation of blood supply. (B) Ureters anastomosed to cecal segment and terminal ileum acting as efferent limb for catheterization. (C) Cecal segment split and pulled over to form a pouch to minimize pouch pressure. (D) Efferent limb brought out for catheterization.

Neobladders may be performed in both sexes and can allow for relatively normal micturition. These patients are able to sense fullness of the reservoir, which they then empty by Valsalva's maneuver. Daytime continence rates approach 100% in some series, but enuresis may occur in some patients (19,22,24,25).

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  • Iolanda
    How to flush an indiana pouch?
    8 years ago

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