Metabolic Complications of Urologic Intestinal Substitutes

[Singular ileum interposition with bilateral implantation of the ureters after Wertheim-Meigs surgery]

Ileum or colon interpositions are qualified procedures for functional ureteral replacement in case of extended ureteric lesions. In most cases, a unilateral interposition is sufficient. Rarely, it is necessary to perform bilateral procedures. We report the case of a 41-year-old female patient with bilateral ureter implantation into a singular ileum segment.

ABSORPTION OF INTRAVESICALLY APPLIED DRUGS: COMPARISON OF NORMAL AND ILEAL AUGMENTED RABBIT BLADDER

PURPOSE

Drug absorption within urinary diversions has been reported to cause prolonged and higher grade toxicity. Therefore, continuous urine drainage has been recommended during chemotherapy in patients with continent urinary diversion. We developed an animal model in which to examine the significance of drug absorption in normal rabbit bladders compared with ileal augmented bladders.

MATERIALS AND METHODS

Ten rabbits with ileal bladder augmentation and 5 control animals were used for absorption studies with methotrexate and ofloxacin. One, 4 and 12 months after surgery the rabbits received an intravesical instillation of either drug. During 2 hours blood samples were drawn. To avoid overfilling the bladder by urine it was emptied after 30, 60, 90 and 120 minutes, and refilled with fresh solution to yield a relatively constant drug amount. After 12 months the animals were sacrificed. Area of the native bladder wall and of the intestinal segment was measured to allow the correction of absorbed drug amounts per surface area. Moreover, the median villous heights of native and augmented ileum were compared histologically. Serum levels of methotrexate and ofloxacin were determined by high performance liquid chromatography.

RESULTS

The maximum serum concentration of the 2 drugs was typically seen after 60 to 120 minutes. During the 1-year period peak serum concentrations of ofloxacin remained consistently higher in ileal augmented than in control rabbits, although this did not achieve statistical significance at all instillation time points. For methotrexate a statistically significant difference was not shown for either time point. When absorption was corrected for total bladder surface area, the enhancement of ofloxacin absorption by ileal augmentation weakened and attained statistical significance only at the 1-month time point. Histological examinations after 12 months showed that augmented intestinal mucosa had a significantly smaller villous height than native ileum.

CONCLUSIONS

Our data demonstrate that bladder surface is the most important factor for increased absorption but time dependent histological changes of the integrated intestinal mucosa also influence absorption. There is a broad interindividual discrepancy. Therefore, general rules in patients with urinary diversion may not be justified.

Litotricia extracorpórea en litiasis en pacientes con derivación urinaria

We evaluate the efficacy of ESWL in the management of calculi in patients with urinary diversion. We treated 5 patients who suffered from urinary lithiasis after urinary diversion post cistectomy. We managed the patients with extracorporeal shock wave lithotripsy in monotherapy with a Siemens Lithostar Modularis device. Mean stone size (long axis) was 1.95 cm (range 1 to 3.5 cm). The mean shockwave number per session was 2.6 per patient. Stone free result was 100%. We conclude that ESWL technique can provide acceptable results in patients with urinary diversion and can be used as first choice treatment in these type of patients due to its minimal morbidity and excellent results, equivalent to those achieved in patients without urinary diversion.

The use of in bowel urology. Metabolic and nutritional complications

Metabolic and nutritional complications of urinary diversion through bowel or stomach segments are common, but fortunately, not often severe. When metabolic abnormalities are problematic, deterioration or baseline insufficiency in renal function is the most likely cause. Deterioration is most commonly associated with obstruction or infection. The urologist should be acutely aware of the potential for metabolic derangements when the prediversion creatinine is greater than 2.0 mg/dL. In this situation, the urologist should employ the basic principles in this article when planning the procedure in order to minimize metabolic complications and morbidities. In the setting of significant renal insufficiency, a short colon or ileal conduit would likely be superior to an ileal or colonic neobladder, or a diversion, incorporating a large gastric segment. Furthermore, in the absence of symptomatic metabolic abnormalities, we advocate treatment of minor laboratory abnormalities, particularly acidosis, to reduce the incidence of metabolic bone disease. Nutritional and gastrointestinal complications are treated on an "as needed" basis, with the exception of metabolic bone disease, which we would hope to prevent with alkalinization and Vitamin C supplementation. Some of the nutritional and gastrointestinal complications are best avoided by leaving the ileocecal valve intact, or by minimizing the use of certain segments. Some evidence exists that over time, histologic changes in the epithelium of diversion segments may impair absorption and contribute to greater resistance against metabolic derangements. Whether the changes truly reduce the incidence of metabolic abnormalities remains to be studied. The ideal, complication-free, diversion with universal application does not exist; however, the urologist must strive to select an option that will provide a functional result for the patient with minimal associated morbidity.

Noncontinent urinary diversion

When the need for urinary diversion arises, whether from carcinoma of the urinary tract, malfunction, or malformation, a decision must be made about the type of diversion to be performed. Currently, the patient and surgeon must decide on continent versus noncontinent versus neobladder, and on the type of intestinal segment to be used.

No evidence of osteopenia 5 to 8 years after ileal orthotopic bladder substitution

PURPOSE

The use of bowel segments as bladder substitutes may result in chronic, impaired vitamin D and calcium metabolism, and ultimately in bone demineralization.

MATERIALS AND METHODS

Bone metabolism was examined in 14 patients who lived for 5 to 8 years with an ileal low pressure bladder substitute after radical cystectomy for bladder cancer. Bone mineral density was measured using dual energy x-ray absorptiometry of the total skeleton, lumbar spine, femoral neck, and tibial epiphysis and diaphysis. Laboratory studies included serum levels of 1,25-dihydroxyvitamin D, 25-hydroxyvitamin D, intact parathyroid hormone, plasma alkaline phosphatase, electrolytes, creatinine and blood gas analysis.

RESULTS

Bone mineral density was normal in all patients. There was no evidence of deficient vitamin D stores. There was a tendency toward slightly elevated serum creatinine values in patients with preexisting impaired renal function, including 1 who also had slight acidosis. No patient had hyperchloremia.

CONCLUSIONS

We found no evidence of osteomalacia, osteoporosis or significant metabolic acidosis in 14 patients with an ileal bladder substitute for 5 to 8 years. However, it is not known whether the absence of osteopenia would also apply to patients with poor renal function, to those not followed meticulously and, thus, at risk for major long-term functional or metabolic disturbances from the ileal bladder substitute or to patients with orthotopic bladder substitutes made from longer or other bowel segments than we used.

A simple ileal substitute bladder after radical cystectomy: experience with a modification of the Studer pouch

Bladder substitution using pouches designed from detubularized bowel is gaining widespread acceptance among urologists and their patients. However, few clinical reports have described the effectiveness of the orthotopic neobladder fashioned from ileum in the manner described by Studer. Since 1988, we have used the Studer technique with minor modifications in 20 men who underwent radical cystoprostatectomy for transitional cell carcinoma of the bladder. Early morbidity from the procedure was minimal, although 2 patients later had anastomotic strictures. Significant late complications included low vitamin B12 levels in 4 patients and persistent hyperchloremia in 1. A total of 18 patients achieved diurnal continence but 9 of these had enuresis. Neobladder compliance and emptying were satisfactory in the 12 patients evaluated urodynamically. Upper tracts remained stable in all patients at a median followup of 24 months (range 9 to 60). Isolated episodes of bacteriuria occurred in 11 patients but followup urine cultures have remained sterile in all continent patients. The Studer ileal neobladder is a simple, effective alternative for urine storage, upper tract preservation and efficient voiding.

Absorption of sodium and chloride in continent reservoirs for urine: comparison of ileal and colonic reservoirs

The absorptive capacity of urinary reservoir mucosa was studied by measuring the fractions of 22sodium and 36chloride absorbed after instillation into reservoirs constructed from an ileal or a colonic segment. The absorption of 22sodium did not differ between the 2 reservoir types but absorption of 36chloride was greater in the colonic reservoirs. The levels of chloride in serum were significantly higher in patients with a colonic than in those with an ileal reservoir. In the ileal reservoirs the absorptive capacity was greater for 22sodium than for 36chloride.

Hyponatremia, hyperkalemia and hypercalcemia after ileal conduit diversion

In all types of urinary diversion interchange of electrolytes between blood and the urine in the lumen of the conduit may occur, resulting in electrolyte abnormalities. We describe a 67-year-old woman who developed hyponatremia, hyperkalemia and hypercalcemia following ureteroileocutaneostomy. The hyperkalemia and hypercalcemia were successfully treated with sodium polystyrene sulfonate.

Continent jejunal reservoir (Kock pouch) for urinary diversion in dogs

Urinary diversion by transplantation of both ureters into a reservoir constructed from 60 cm of jejunum was performed in six clinically normal dogs. The reservoir was connected to a stoma on the abdominal wall through a valve constructed from a short segment of intussuscepted bowel to provide continence. The reservoir was emptied three times daily by catheterization. One dog did not survive the surgical procedure and two dogs died within 1 week of surgical complications. The postoperative capacity of the reservoir in surviving dogs was 100 to 200 mL; it increased during the first month to 600 to 750 mL. Continence was excellent in two dogs. One dog was continent until month 2, when partial slippage of the intussusception occurred. A reversible hyponatremic, hypochloremic, hypokalemic metabolic acidosis developed. Bacteriuria was not responsive to systemic or local instillation of antibiotics. Ascending pyelonephritis, hydroureter, and hydronephrosis occurred in two dogs. Struvite urinary calculi formed in one dog. The procedure as described would be unsuitable for clinical use in dogs.

A 55-year followup of a patient with bilateral ureterosigmoidostomy

We report on a patient with bilateral ureterosigmoidostomy who, despite many of the long-term complications associated with the procedure, was doing well 55 years after urinary diversion. This is one of the longest follow-ups reported in the literature. Despite the decreasing popularity of ureterosigmoidostomy, in well selected patients who desire a continent form of internal diversion it may still prove to be useful, as exemplified by our patient.

Current procedures for bladder substitution and urinary diversion at King Faisal Specialist Hospital and Research Centre

Following radical cystectomy for bladder cancer, 14 male patientts had a detubularized colic or ileocolic bladder substitute anastomosed to the membranous urethra and two female patients had urinary diversion to the valved and augmented rectum. There were no early deaths and the complication rate was low. The patients were followed for a mean of 12 months (2-28 months). During this short-term follow-up, no patients suffered deterioration of renal function or symptomatic urinary tract infection. Of the male patients, nine were perfectly continent, four had some incontinence during sleep, and one patient was incontinent day and night. Four had normal erections and three weak erections. Three have received penile implants, but it is too early to assess the need for this in the others. The two female patients were continent. Continent urinary diversion without a stoma appears to be a safe and reliable procedure, and patients should be offered one of these newer alternatives for replacement of the urinary bladder after cystectomy for cancer.

Enterocystoplasty with cystectomy and subtotal intracapsular prostatectomy in the male dog

Urinary diversion by implantation of the ureters into an isolated segment of jejunum was evaluated in eight clinically normal male dogs. Total cystectomy and subtotal intracapsular prostatectomy were performed, and the intestinal loop was sutured to the prostatic remnant. General health, renal function, acid-base balance, urinary tract infection, and urinary continence were monitored during observation periods of 4 to 30 weeks. All dogs survived the observation period and seven were in excellent general health at the time of euthanasia. Six of the 16 ureterointestinal anastomoses were complicated by complete ureteral obstruction. Absorption of urea from the intestinal loop was speculated as the reason for significant increases in serum urea nitrogen concentrations in all of the dogs. Serum creatinine concentrations generally remained within the normal range, but were significantly increased from preoperative baseline values by week 30. There was dilation of 12 renal pelves and ureters in seven dogs. Urine bacterial cultures were positive in six dogs, but histologic evidence of pyelonephritis was present in only five kidneys. Ejaculation was not affected by the procedure, but epididymitis was present in five dogs. The dogs could urinate consciously and did not dribble urine continuously; however, they urinated hourly. While the procedure was well tolerated by the dogs, the frequency of urination makes this technique unacceptable for most household pets.

Prospective study of metabolic abnormalities in patient with continent Kock pouch urinary diversion

Metabolic alterations as a result of bowel being employed in the urinary tract are well documented. To investigate this phenomenon in the continent ileal reservoir urinary diversion, 106 patients who had undergone Kock pouch surgery were followed in a prospective study at the University of Southern California between 1985 and 1987. Serum chemistries and urine osmolality determinations were performed approximately every three months for a year. Mean patient values for each time period were then compiled and compared with the norms and with the preoperative values. The mean serum electrolyte values were found to be within normal limits during all follow-up periods. Fourteen patients were identified, however, as having values falling intermittently outside of the normal range. These patients were investigated and found to be abnormal during episodes of acute renal failure usually secondary to dehydration or obstruction at which time they usually became acidotic and occasionally hyperchloremic. These problems disappeared when the renal failure was corrected. This study corroborated our previously reported findings that hyperchloremic acidosis or other metabolic alterations requiring replacement therapy do not routinely occur in this population.