Before choosing an ileal conduit, patients should be counseled on all forms of diversion. Comorbidities such as renal insufficiency (serum creatinine >1.5 mg per dL or glomerular filtration rate <50 mL per minute), bowel disease (inflammatory or malignant), extreme obesity, or neurologic illness that prevents the ability to perform self-catheterization may make incontinent diversion a wise choice. Although it was suggested in the past that patients with cardiovascular/pulmonary disease or advanced age may do better with the shorter, simpler conduit diversions, newer evidence suggests that perioperative morbidity is equivalent with conduit and continent diversions (1,2).

Continent catheterizable or orthotopic voiding diversions are the most common alternatives to conduit diversion. In addition, choices exist within incontinent diversion with respect to bowel segment (ileum, jejunum, stomach, and colon) and/or the type of ureteroenteric anastomosis (refluxing versus nonrefluxing). Conduits from nonileal bowel may be associated with higher metabolic complications but may be the only option in some patients. Further, the ability to accommodate nonrefluxing anastomosis in colonic conduits may protect kidney function and be preferable in children or adults with long life expectancy. Additional types of diversion are described elsewhere in the text. Patients undergoing concurrent pelvic exenteration are presented with additional options, including sigmoid conduits with transverse colostomy to avoid bowel anastomosis or the use of the double-barrel wet colostomy to drain both the fecal and urinary streams through a single tract.

Other potential urinary diversions include an ileovesicostomy, which can be used in benign disease to avoid complications associated with ureteral mobilization and anastomosis. Finally, patients with limited life expectancy may be considered for percutaneous nephrostomy tubes.

Traditionally, surgical pathways for ileal conduit diversion have included preoperative bowel preparation. More recently, however, studies have shown that omission of this step may be done without adverse outcomes, including gastrointestinal or infectious complications (3,4). Broad-spectrum antibiotics are given at the time of surgery. The stoma site should be selected after examining the patient in the supine, seated, and standing positions. To best accommodate an appliance, the site should not be too near the anterior superior iliac spine, costal margin, umbilicus, surgical scars, or skin folds. The usual ideal location is just medial to the linea semilunaris, approximately onethird of the distance on a line between the umbilicus and the anterior superior iliac spine.

Markedly obese patients may require a higher site to allow them to perform stoma care under direct vision. In instances where there is a question regarding the ideal stoma site, ambulatory trials of pouching candidate sites or preoperative consultation with enterostomal therapy (where available) can help determine the optimal location.

The increasing prevalence of laparoscopy and robotics in pelvic surgery has led to the development of techniques using these for creation of the ileal conduit. Traditionally, creation of the urinary diversion had occurred extracorporeally after completing the laparoscopic portion of the case (as in radical cystectomy), but improvements in technique have allowed creation of urinary diversions completely intracorporeally. Initial reports of intracorporeal ileal conduit creation demonstrated this procedure to be both reasonable and safe (5). More mature data has compared the intracorporeal and extracorporeal diversions (both continent and incontinent) with respect to patient outcomes. The data showed similar operative times and reoperation rates and further suggested decreased complication rates among patients with intracorporeal diversions (6). Despite this, it should be noted that open approach to urinary diversion remains the standard of care given the surgical expertise
required as well as lack of prospective data evaluating the minimally invasive approach and as such will be the procedure described in the following text. Further, associated procedures such as radical cystectomy require a minilaparotomy incision for specimen extraction limiting the benefits of completely intracorporeal diversion. Detailed techniques for intracorporeal creation of ileal conduit exist in the literature (7).

A low midline incision extending from just below the umbilicus down to the symphysis pubica allows for exposure of the bladder for cystectomy as well as bowel exposure for the conduit portion of the procedure. The patient is positioned supine. A Bookwalter-type retractor may be used to retract the bowel from the cystectomy field, and then the blades may be repositioned on the abdominal wall for the conduit procedure. The posterior peritoneum is incised at the pelvic inlet above the iliac vessels, where the ureter can be found coursing over the vessels. The ureters are then dissected with care distally and transected as close to the bladder as possible. A lesser degree of proximal mobilization is also usually necessary. During mobilization of the ureter, care should be taken to maintain its blood supply by leaving a generous amount of periureteral soft tissue. The distal ends of the ureters may be clipped to allow dilatation while the ileal conduit is harvested and prepared. The terminal ileum is then identified and examined. If signs of inflammatory bowel disease, radiation changes, or insufficient mesenteric length are not present, then this segment is in general preferred for conduit formation. The mesentery is examined by transillumination, and the watershed area between the ileocolic artery and the right colic artery is selected for the distal mesenteric incision. This is typically located 20 to 25 cm proximal from the ileocecal valve, and the preservation of this length of terminal ileum suffices to maintain bile salt and vitamin B12 absorption. The bowel incision is continued proximally into the mesentery to allow the distal end to reach the stoma site without tension. Figure 75.1 demonstrates the isolation of the ileal segment.

The mesentery is again transilluminated, and a relatively avascular site is selected for the proximal incision. The optimal length of the conduit differs from patient to patient due to differences in body habitus and the degree of ureteral mobilization. The longest length of conduit should not exceed the distance between the sacral promontory and the stoma site; usually, if there is adequate left ureteral mobilization, a shorter length than this is optimal. If there is any question regarding the length, one should err on the longer side, as redundant conduit is much easier than insufficient conduit to treat intraoperatively. The conduit and its mesentery are positioned caudal to the rejoined bowel and its mesentery.

Standard hand-sewn or staple techniques are then performed to reestablish bowel continuity. The mesenteric window is also closed with a shallow running suture to prevent internal bowel herniation. Care should be taken during closure of the mesenteric window to avoid ligation of the ileal blood supply, which might compromise the healing of the anastomosis. Sterile towels are placed beneath the isolated ileal conduit, which is irrigated free of enteric contents with an antibiotic solution.

At this point in the procedure, either stoma formation or ureteroenteric anastomosis can be performed. This choice is based on surgeon preference. If ureteral stents are to be used, performing the ureteroileal anastomosis first allows for easier antegrade passage of the stent out of the distal end of the conduit. Creating the stoma first provides for more optimal localization of the ureteroileal anastomotic sites and helps direct the optimal level of the sigmoid mesentery through which the left ureter should be passed.

Construction of the stoma begins with the excision of a circular plug of skin around the preselected stoma site. Dissection is carried down to the anterior rectus sheath, and a cruciate incision is made in this layer. The posterior rectus sheath and rectus muscle are bluntly dissected after taking care to avoid the epigastric vessels. This dissection may be accomplished with a Kelly clamp, which then may be spread to create a hiatus for the conduit to pass through the abdominal wall. Traditionally, creating a hiatus approximately two fingerbreadths wide has been considered ideal to prevent compromise of mesenteric blood flow to the stoma. However, the rate of parastomal hernias in this population has been high, especially in obese patients (8). Ultimately, the size of the hiatus should depend intraoperatively on the width of the conduit. Creating a narrow passage will increase the risk of stomal stenosis, stomal retraction, or compromise of the blood supply. Conversely, a wide hiatus will predispose toward hernia and prolapse (9). To decrease the risk of parastomal hernia, the posterior rectus sheath is fixed with four separate sutures to the ileal conduit in order to prevent a sliding hernia.