It is wise to first use less invasive measures when possible and proceed to augment only if these prove insufficient. Videourodynamic evaluation provides information about bladder compliance, overactivity, outlet resistance, and vesicoureteral reflux (VUR) that is critical in surgical planning. Although successful augmentation can protect the upper tracts and potentially provide for continence, there are potential risks and obligations for ongoing care that patients (and families) must be aware of before choosing to proceed.
Patients should assume that lifelong clean intermittent catheterization (CIC) will be required after augmentation. Additionally, at least once weekly, bladder irrigation to clear mucus is recommended. Early complications may include bowel leak or obstruction, abdominal infection, urinary tract infection, or persistent urinary leak from the augmented bladder. Long term, the patient with renal insufficiency may develop acidosis, and all augmented patients have an increased incidence of bladder stone and tumor formation, which requires surveillance cystoscopy beginning at 10 years postoperatively. Finally, rupture or perforation of an augmented bladder may occur and require urgent repair.
When augmentation is needed, ileum is often the bowel segment of choice. Studies have not documented reasons to choose ileum, but the proximity to bladder and mobility of the mesentery make it easy to work with. The surgeon should preserve the final 20 cm of the terminal ileum (minimum) to assure adequate bile salt and vitamin B 12 absorption. Patients with an ileal augmentation should have vitamin B 12 levels checked beginning 5 years after the procedure.
The patient is positioned supine. Either a Pfannenstiel or low-midline (below the umbilicus) incision may be used ( Fig. 60.1, A ). The midline approach can easily be extended superiorly if exposure is difficult. The patient is placed in slight Trendelenburg position, and the bladder is exposed. If the patient requires a bladder neck procedure or ureteral reimplantation, it is often helpful to avoid opening the peritoneum until these ancillary procedures are completed. Leaving the peritoneum closed early on and using a Bookwalter retractor maximizes exposure by keeping bowel loops contained and avoids unwanted evaporative loss. If either a Mitrofanoff or Monti channel is being created, the peritoneum is opened to allow access to bowel at that point.
The bladder is widely split, starting 2 cm above the bladder neck anteriorly and continuing over the dome to just above the interureteric ridge posteriorly. To accommodate a stoma, it is sometimes helpful to split obliquely, leaving the larger bladder half on the side of the stoma. The bowel is then inspected, and an ileal segment 20 to 30 cm in length is chosen.
The mesentery is taken down and the bowel is divided with either gastrointestinal anastomosis (GIA) staplers or Kocher clamps. Integrity of the ileum is reestablished and the mesenteric window closed. The isolated segment is irrigated by partially opening each end and flushing through with either genitourinary irrigant or half-strength Betadine. The segment is next opened completely on its antimesenteric side using cutting current of the cautery with careful spot coagulation for bleeding points ( Fig. 60.1, B ).
The edges of the open bowel plate are then rotated into position for a detubularizing reconfiguration ( Fig. 60.2 ). Suturing is carried out with 3-0 polydioxanone (PDS) or Vicryl in a running fashion with occasional locking throws and knots tied on the serosal (outside) surface. It is important that each suture bite include slightly more serosa and muscularis than bowel mucosa, so that the mucosa is rolled inward each time the suture is tightened. When complete, the running suture line should not have mucosa peeking between bites because this can predispose to persistent urine leak. After the initial suture line is completed, the bowel is folded again ( Fig. 60.3 ) into the rough form of a cup. It is important that these two suture lines are stopped at a point that will leave the circumference of the “cup edge” roughly equal to the circumference open bladder edge to facilitate a watertight sutured closure.