Cutaneous Pyelostomy, Ureterostomy, and Noncontinent Vesicostomy

Unlike adults where prolonged drainage of the urinary tract system can be safely performed by percutaneous nephrostomy or suprapubic cystostomy tubes, attempted management of infants by continued percutaneous access is associated with a 40% incidence of complications. Specifically, frequent tube dislodgment, urinoma, or obstruction will occur in 15%; infectious complications, pyelonephritis, cystitis or urosepsis in 15%; and bleeding complications, retroperitoneal hemorrhage, or chronic anemia with the need for transfusion due to low-volume but persistent blood loss in 10%. Due to the frequency of these complications the surgeon should consider the use of tubeless diversions, such as cutaneous pyelostomies, ureterostomies, or vesicostomy, in any infant where definitive reconstruction is to be delayed for greater than 6 months. Classically, cutaneous pyelostomy or ureterostomies are performed in infants presenting with an infected obstructive ureter(s), bladder hypoplasia/agenesis, or as a palliative procedure in infants with large nonresectable pelvic tumors. Cutaneous pelvic or ureteral stenosis will occur as a postoperative complication in 10–15% of these cases and recurrent pyelonephritis in 20%. When pyelonephritis does occur it is usually associated with either a cutaneous stenosis or a poorly functioning kidney associated with urinary stasis. In these latter patients, resolution of the recurrent infections is best treated by nephrectomy.

A cutaneous noncontinent vesicostomy is a temporary urinary diversion used to decompress the bladder and upper tracts in the presence of bladder outlet obstruction. It is classically indicated for the following conditions: (1) in infants with posterior urethral valves where the urethra is too small for endoscopic instruments; (2) in patients with neurogenic bladders, cloacal anomalies, or imperforate anus where urethral catheterization is difficult; (3) in patients with common cloacal or imperforate anus where urethral–rectal fistulas have resulted in metabolic abnormalities or repeated urinary tract infections (UTIs); and (4) in infants where parenteral noncompliance with medical directives is a concern. Revision of the vesicostomy due to either stenosis or prolapse will be necessary for 10% of infants. Although this is an excellent form of temporary urinary diversion in neonates, its use becomes more problematic after 3 years of age. Specifically, with maturation, the bladder changes from predominantly an intraabdominal to a pelvic organ. The relative change in position will result in the need to significantly mobilize the bladder to reach the skin level and be associated with increased tension on the vesicocutaneous anastomosis resulting in a significantly increased risk of vesicocutaneous stricture formation in the older child or adult. As the child matures attempts to cover the stoma with diapers, protective clothing, or a collection bag become increasingly problematic with the stoma location usually being cephalad to the areas covered by protective clothing. The stoma is also in a highly mobile area, associated with multiple skin folds, which significantly hinders the patient’s ability to maintain a stomal collection bag. The inability to successfully contain the urine results in problems with skin irritation, breakdown, need for frequent clothing changes, and a decrease in the societal acceptance of the malodorous patient. Take down of a cutaneous vesicostomy is therefore commonly pursued between 1 and 2 years of age.

Neoplasia

The development of a malignant tumor within a urinary reservoir or augmented bladder is based on the type of bowel used, the length of time from surgery, the concurrent use of immunosuppressives, and the etiology for primary bladder dysfunction. It is noteworthy that the overall risk for development of a bladder malignancy is increased in all patients with a primary congenital bladder dysfunction. The incidence of bladder cancer development within this population is approximately 1% per decade. This risk is not significantly increased if these patients undergo an ileal or a colonic bladder augmentation; reported incidence following these procedures is approximately 1.5% per decade. This risk is, however, approximately tripled to 2.8% per decade for patients undergoing a gastric augment and is increased approximately fivefold, i.e., 5% per decade, following a ureterosigmoidostomy. Two specific patient populations appear to be at an increased risk for tumor development following a bladder augmentation; specifically, patients who have undergone a gastric augment and patients with an augmentation who are on immunosuppressives. Both of these patient populations appear to have between a two- and threefold increased risk for cancer development compared to patients with a primary congenital bladder dysfunction.

The question that arises is, should patients with congenital bladder dysfunction treated by bladder augmentation be routinely screened by annual endoscopy and cytology? We currently do not believe data exist that can support this recommendation. Specifically, the World Health Organization recommends annual cancer screening be performed when the four following criteria are met: (1) cancer has a high prevalence within a well-defined patient population; (2) cancer routinely presents at a low treatable stage; (3) screening tests are available that are safe, inexpensive, reliable, and reproducible with high specificity and sensitivity; and (4) the screening test must allow the cancer to be diagnosed at a low treatable stage and result in an improved patient prognosis.

Currently, epidemiologic and pathologic findings reveal tumors arising within a congenitally dysfunctional bladder cannot meet these criteria. Specifically, 5–7.5% of patients with congenital bladder dysfunction with or without an augment will develop a bladder cancer by the sixth decade of life, a 1–1.5% risk of malignancy per decade. Approximately 80% of these patients will present with locally advanced disease or nodal metastasis at the time of diagnosis, with a cancer-specific mortality of 80% at 18 months following the diagnosis.

Pathologic evaluations inevitably reveal unique morphologic, immunohistochemical, and genetic tumor alterations that are associated with rapid tumor growth, i.e., brisk mitotic activity, lymphovascular invasion, tumor necrosis, and a high incidence of invasion into or through the bladder or bowel muscle at the time of diagnosis. Indeed, in support of the findings reviewed above are five cases of malignancy that arose within an augmented bladder where routine cystoscopic evaluations had been normal 4–18 months prior to the development of an invasive malignancy that eventually proved to be fatal.

In essence low-stage medically or surgically curative bladder cancer can rarely be detected by annual screening endoscopic and cytologic studies. Indeed, it is our belief that the costs of these studies far outweigh the prevalence of the disease and have no proven benefit in diagnosing early-stage and curable tumors.

Spontaneous Bladder Perforations

This complication is associated with significant patient morbidity with a reported mortality incidence of approximately 25%. Spontaneous bladder perforations may occur at any time ranging from the first postoperative year to more than 30 years following the augmentation. Their incidence varies from 2% to 10% and is related to the findings of post augment, high leak point pressures, compliance with intermittent catheterization, and length of follow-up.

Diagnosis of a spontaneous rupture of the augment can be problematic due to the large number of patients with impaired sensation that have undergone this procedure, e.g., patients with spina bifida or spinal cord injury. Patients with decreased sensation will frequently present with vague symptomatology, such as malaise and nausea, with or without associated diaphragmatic irritative symptoms, i.e., persistent hiccups or shoulder pain. Without interventional treatment patients will usually progress to complaints of vomiting, fever, abdominal pain with or without abdominal distention, and physical findings consistent with peritoneal irritation. From a urologic standpoint, the differential diagnosis will be small bowel obstruction, severe cystitis-pouchitis, or ruptured viscus, pouch, or augment. The diagnostic test of choice is an abdominal and pelvic CT without contrast followed by a CT cystogram.

Although case reports of successfully managing spontaneous bladder perforation by nonoperative measures, that is, larger bore urethral catheter drainage, intravenous antibiotics, and serial physical examinations, have been reported, the physician should remember the 25% mortality rate associated with this diagnosis.

Radiographic or physical findings of extruded bladder calculi outside of the augment, the presence of omentum or small bowel within the bladder lumen, progressive peritoneal irritation, and/or hemostatic instability should prompt an immediate abdominal exploration. Surgery will require irrigation of the peritoneal cavity, repair of the bladder rupture, and consideration for externalization of the ventriculo-peritoneal shunt, if one is present.

Bladder and Renal Calculi

Bladder stone formation following urologic reconstruction is directly related to the type of augmentation performed, the use of a continent catheterizable abdominal stoma, patient compliance with medical directives, and length of follow-up. Of note is that the incidence of bladder stones following augmentation has significantly decreased over the past 2–3 decades. For example, in the early 1980s 50% of the individuals undergoing an ileal or colonic bladder augmentation developed a bladder calculi within 5 years of the augmentation, and 50% of the patients that developed a bladder stone had a recurrent bladder stone within 5 years. The metabolic composition of these stones was found to be struvite, i.e., infectious, in etiology in 70% of cases. Thirty percent of the bladder stones were, however, composed of metabolic active components, e.g., calcium phosphate or calcium oxalate. Stone analysis usually revealed that the calcium salts had precipitated around a mucous core, with approximately 85% of the stones concurrently having positive bacterial cultures. The finding of metabolically active calcium phosphate stones within a bladder augment is not surprising, based on the high alkalinity of the urine following either augmentation or creation of a continent urinary reservoir with ileum or colon. Specifically, alkaline urine is invariably present due to ammonium chloride absorption and bicarbonate secretion from the bowel wall. Compounding the problem of an elevated pH are the low levels of urinary citrate, a known urinary inhibitor of stone formation. Hypocitraturia is invariably present and directly related to the presence of chronic bacteriuria, with the vast majority of bacteria actively catabolizing citrate. The combination of elevated urinary pH, retained mucus serving as a nidus for crystallization, chronic bacteriuria, and low urinary citrate creates the perfect environment for the precipitation of calcium salts.

Over the past 3 decades, significant strides have been made in decreasing the incidence of stone formation following augmentation or continent urinary diversion. The decrease in the incidence of stone formation has been achieved predominantly by irrigation of the bladder with a minimum of 250 mL of water or saline solution on a daily basis. Use of high-volume daily irrigations coupled with a minimum of four times daily catheterization schedule has been documented to decrease the incidence of chronic bacteriuria, symptomatic UTIs, and bladder stones. Currently, if patients are compliant with high-volume daily bladder irrigations, approximately 10% of the patients will develop a bladder stone by the tenth postsurgical year.

Although high-volume bladder irrigations have helped to reduce bladder stone formation, it is far from a panacea. In patients presenting with a second bladder stone, despite high-volume irrigation, 30% will have a third recurrent bladder stone within 5 years. Metabolic evaluations of patients with recurrent bladder stones will reveal hypocitraturia in >90% of individuals. In addition to the almost ubiquitously found hypocitraturia, either coexisting low 24-hour urinary volumes (<1600 mL) hypercalciura or hyperoxaluria will concurrently be found in one-third of the patients. Although treatment of metabolic abnormalities has been documented to decrease renal calculi, it is controversial if treatment of underlying metabolic abnormalities will reduce the incidence of recurrent bladder calculi. In fact, in our experience with patients with recurrent bladder calculi and a coexisting identifiable metabolic abnormality, correction of the metabolic abnormality did not significantly decrease the risk of recurrent bladder stone formation compared to the controls.

Once we recognized that treatment of the underlying metabolic abnormalities was not reducing the incidence of recurrent bladder stones, we attempted to decrease recurrent stone formation using mucolytic agents, such as 20% N -acetylcysteine or 10–20% urea instilled in the bladder at night along with high-volume bladder irrigation. It was our hope that the addition of mucolytics would enhance dissolution of the mucous nidus and decrease the incidence of recurrent stone formation. Unfortunately, in a clinical trial comparing the use of high-volume bladder irrigation alone compared with high-volume bladder irrigation with the use of indwelling mucolytics overnight, we found no difference in stone formation between the two groups (30% at 5 years). In essence, in patients who experience recalcitrant bladder stone formation following augmentation, we have found that neither treatment of the underlying metabolic abnormality nor the use of mucolytic agents decreased the frequency of recurrent stones over high-volume bladder irrigation alone. This latter finding has been confirmed in a double-blind placebo-controlled study by N’Dow and associates. These authors found that neither N -acetylcysteine nor ranitidine, an H ₂ blocker that reduces mucus secretion, was found to be of any benefit over placebo alone in the prevention of recurrent bladder calculi.

The question arises as to what to do with this difficult patient population. Currently, in patients of ours who are forming recurrent bladder stones, we will, in addition to the high-volume bladder irrigations (250 mL per day), use a 60-mL solution of 20% acetylcysteine placed into the bladder at night. In patients with concurrent hypocitraturia, we will also correct their urinary citrate levels. We would caution that we have absolutely no clinical documentation that this treatment will substantially decrease the risk of additional stones, and this treatment regimen is done as an empiric trial.

During our 20-year follow-up of patients with an ileal or colonic bladder augmentation, we have found that approximately 15% of patients will develop a renal stone, with a median time to stone development post augmentation of 16 years (see Table 62.1 ). Stone analysis will reveal the renal calculi to be of infectious etiology, i.e., struvite, in 40% of cases. The struvite calculi will invariably be associated with a urease-splitting organism colonizing the upper tract. In these circumstances assessment for vesicoureteral reflux may be merited, and it is our unsubstantiated belief that free reflux of mucus into the collecting system results in a high risk of stone recurrence. Consideration for repair of the reflux, if found, should be given. Interestingly, the majority of renal stones within this patient population are associated with metabolic abnormalities such as hyperoxaluria, hypocitraturia, hyperuricosuria, and hypercalciura. The induction of hyperoxaluria, hypocitraturia, and hyperuricosuria are believed to arise as a consequence of a shortened bowel with rapid bowel transit time, saponification of calcium to fatty stools, chronic bacteriuria, and metabolic acidosis. The level of hyperoxaluria can also be affected if chronic antibiotic suppression is used resulting in loss of Oxalobacter formigenes the gut flora that metabolizes intestinal oxalate. Hypercalciuria classically arises in patients with a known neuropathy due to impaired mobility, or mobilization of calcium phosphate from bony stores to buffer the metabolic acidosis induced by the augment.

Need for Secondary Augmentations

The need for a repeat or secondary augmentation has been reported to be necessary for 5–10% of patients. The need for re-augmentation usually comes to attention due to the findings of either persistent or new onset of urinary incontinence or hydronephrosis. The need to re-augment is confirmed by urodynamic evaluation. Urodynamic findings will reveal either impaired compliance or resumption of bladder/bowel contractions. The findings of impaired compliance are believed to be due to an inadequate-sized initial bladder augmentation, vascular impairment of the augment resulting in its fibrosis, or the inherent native characteristics of the augmenting segment. Regarding the inherent characteristics of the augmenting segment both the stomach and sigmoid colon have been found to be problematic. Specifically, ileal or ascending colon augments have been shown to improve their compliance and subsequently increase the bladder capacity on serial postoperative urodynamic studies over the first 3–5 years post augmentation. In contrast, gastric augments exhibit little to no improvement in compliance following the initial postoperative urodynamic evaluation, i.e., no serial improvement in compliance. The problem with sigmoid augmentation relates to its ability to redevelop strong autonomic contractions despite its detubularization at the time of augmentation. The resumption of high-pressure sigmoid mass contractions is associated with upper tract deterioration, urinary incontinence, and spontaneous bladder perforations. These clinical findings strongly suggest that close long-term observation of patients undergoing augmentation with gastric or sigmoid segments is necessary, especially if these procedures are combined with a bladder outlet procedure.

Small Bowel Obstruction

The need for hospitalization to manage small bowel obstruction is dependent upon the length of follow-up. During the first 2 decades post augmentation, hospitalization will be required in 10–15% of patients, with exploratory laparotomy required in 5%. Of note is that patients requiring exploration for a small bowel obstruction will frequently be found to have an internal hernia with the small bowl volvulus intricately involving the vascular pedicle to the augment or continent stoma. Damage to the blood supply to the augment or stoma is, therefore, a distinct concern at the time of surgery.

Stomal Revision of Urinary Conduits or Revision of Catheterizable Limb

The incidence of stomal complications in both urinary conduits and catheterizable limbs is directly related to the surgeon’s experience, the patient’s body mass index, and the length of follow-up. Regarding urinary conduits, stomal, midloop stenosis or parastomal hernias will occur in up to 40% of ileal conduits and 15% of colon conduits by the tenth postoperative year. As noted previously, these complications are frequently related to deterioration of the upper tracts, and routine evaluation for their presence should be an integral part of the patient’s follow-up. If obstruction of the stomal outlet is found it should be immediately addressed by either long-term radiologic intervention with interval stenting of the kidneys and conduit, or surgical revision.

Approximately 75% of children undergoing a bladder augmentation will have the simultaneous performance of a continent catheterizable stoma. The continent stoma is classically performed to either aid the child in his/her ability to catheterize from a wheelchair, to decrease the discomfort of catheterizing through the urethra, to prevent problems with catheterization through a reconstructed bladder neck, or due to surgical closure of the bladder neck. Catheterizable channels are performed using either the principles of the Mitrofanoff procedure, e.g., appendovesicostomy, Montie-Yang tubes, or tapered ileal tubes with a reinforced ileocecal valve. Postoperative complications with stomal leakage of urine are reported to occur in 5–10% of the patients. Incontinence secondary to a faulty valve may be treated with either a bulking agent or revision of the anastomosis. However, if on urodynamic evaluation urinary incontinence is found to be due to persistent elevations in storage pressures or recurrent mass contractions of the augmented bladder, re-augmentation of the bladder, not stomal revision, will be necessary. On occasion we have seen the delayed onset of stomal-site urinary incontinence develop years to decades following the surgical procedure. The late onset of stomal incontinence is frequently due to the development of obesity, with successful weight loss resulting in the patient regaining urinary continence. Alternatively, we have also seen the delayed onset of incontinence secondary to development of a false passage within the catheterizable limb that will require surgical revision. Difficulty with catheterization of the continent limb will be reported in 20% of the patients managed by appendicovesicostomy and Montie-Yang procedures, and in 10% of patients with a tapered ileal channel, by their tenth postoperative year. Unfortunately, we have seen this complication continue to increase with time, especially in patients who gain significant weight as they mature, with difficulty with catheterization reported to occur in up to 50% of the patients by the third postoperative decade. Difficulty with catheterization may arise secondary to either stenosis at the cutaneous or midfascial levels, kinking of the stoma channel, or creation of a false passage or diverticulum within the catheterizable limb. Approximately 50% of the patients may be managed by use of an L-shaped stent at night time. Unfortunately, it will not work in all patients, and approximately 50% of patients will require a formal revision or creation of a new channel.