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

Metabolic and Nutritional Consequences of Urinary Diversion Using Intestinal Segments to Reconstruct the Urinary Tract

Intestinal segments in various forms have been used to reconstruct the urinary tract since the mid-1800s. Currently, many different forms of continent and incontinent diversion options exist. Incorporating bowel mucosa within the urinary tract leads to predictable metabolic and nutritional consequences. The use of ileum or colon can cause a hyperchloremic metabolic acidosis, vitamin B12 deficiency, osteoporosis, fat malabsorption, urinary calculi, and ammoniagenic encephalopathy. Due to metabolic and nutritional consequences associated with the use of jejunum and gastric segments, the use of these bowel segments is not recommended.

Is chronic alkali therapy in orthotopic ileal neobladders necessary? A prospective controlled study

PURPOSE

To evaluate the necessity of chronic alkali therapy in non-complicated orthotopic ileal neobladders with normal renal function.

MATERIALS AND METHODS

This is a prospective study that included 200 male patients who underwent radical cystectomy and ileal W neobladder for invasive bladder carcinoma between January 1993 and December 2013. The studied patients included 100 consecutive patients who were maintained on regular alkali therapy since surgery and 100 consecutive patients who stopped the use of alkali treatment after initial 3 months postoperative with minimum postoperative observation time of 1 year. All patients had satisfactory function of the reservoirs with normal upper tract. The patients were subjected to blood analysis for creatnine, electrolytes, pH and bicarbonate and urine chemical analysis. The study also included 40 healthy male age-matched volunteers who served as a control group.

RESULTS

Both groups were comparable as regard age, BMI, follow-up period and surgical technique. There were no significant differences between both groups as regard serum creatnine, electrolytes blood pH and bicarbonate and the mean values were within normal range; however, the neobladder patients are still toward the acidotic side in comparison to healthy volunteers. Also there were no significant differences between both groups of patients as regard urine pH and excretion of electrolytes, calcium, phosphorus and creatnine.

CONCLUSION

Patients with non-complicated ileal neobladders with normal upper tract who were not maintained on alkali prophylaxis for long period have a compensated acid base status. Therefore, the prolonged alkali prophylaxis is not mandatory.

Morphological changes on the intestinal mucosa in orthotopic neobladder

INTRODUCTION

The intestinal mucosa undergoes significant atrophic changes when it is used to reconstruct the urinary tract. We analyzed the ultrastructural changes of intestinal mucosa in the orthotopic neobladder on the basis of our clinical experience.

PATIENTS AND METHODS

Fifteen male patients with an ileal neobladder underwent endoscopic biopsy at different postoperative intervals.

RESULTS

No significant changes were observed 3 months after surgery. After 6 and 12 months, the structure of the microvilli was modified significantly. No other substantial changes after 24 months were observed.

CONCLUSIONS

Progressive modifications occur in the cytoplasmic structures involved in the absorptive process. They do not seem to begin before 3 months and are almost totally completed after 1 year.

[Metabolic aspects of bowel use in urologic surgery]

Urinary diversion, pouches and orthotopic bladder replacement have been made possible by the use of bowel segments in urologic surgery. The most important complications at short and long-term are metabolic disorders due to the permanent contact of urine with the bowel segment or the exclusion of this segment from bowel continuity. Metabolic acid-base problems occur immediately after the derivation beginning and depend on the renal capacity to compensating. The metabolic disorder due to the exclusion of a bowel segment appears generally years later, after complete depletion of physiologic reserves (vitamin B12). Perfect knowledge of early and late metabolic complications of urinary diversion allows a more accurate indication, a more adequate selection of the derivation type, an improved patient followup, and better long-term results. Metabolic complications constitute the best selection criteria for urinary diversion; subsequently, only a few techniques are likely to persist in the future.

Urinary diversion: options, patient selection, and outcomes

Improved survival following radical cystectomy for bladder cancer as a result of advancements in combination chemotherapy and surgical technique has resulted in a philosophical change in the surgeon's approach to urinary diversion selection. Aims have evolved from the mere diversion of urine to a functional bowel conduit such as an ileal conduit or ureterosigmoidostomy, to providing the optimal diversion for the patient's quality of life. While quality of life is important, one must also consider the stage of cancer and individual patient comorbidities. Which diversion provides the best local cancer control, the lowest potential for complications (short and long term), and the easiest emotional adjustment in lifestyle while still allowing the timely completion of chemotherapy and therapeutic goals? A multidisciplinary approach to diversion selection that includes the patient, the medical oncologist, radiation oncologist, internist, and surgeon is ideal. We describe the three most commonly used types of diversions today, including conduits, continent cutaneous reservoirs, and orthotopic urethral diversions, as well as issues relative to patient selection and functional outcomes in patients undergoing radical cystectomy for the treatment of bladder cancer.

Acid-base and electrolyte disorders after urinary diversion

The use of bowel in urologic reconstructive procedures may result in numerous short and long-term complications, including well-described acid-base and electrolyte disorders. Many of these metabolic alterations are influenced by how solute absorption occurs across the particular bowel segment chosen for reconstruction. Solute absorption is impacted by: (1) the segment of bowel used, (2) the surface area of bowel used, (3) the time of retention of urine, (4) the concentration of solutes in the urine, (5) renal function, and (6) the pH and osmolality of the urine. These factors affect the type and amount of solutes absorbed, as well as the severity of metabolic complications that develop.

Early histological changes of ileal mucosa after augmentation cystoplasty

Segments of bowel are used routinely for transplantation in various pathological conditions such as contracted bladders or poorly compliant neuropathic bladders. However, little is known how these intestinal segments adopt to a toxic environment caused by urine. Therefore, the present study was performed to determine early histological changes of ileal mucosa after augmentation cystoplasty. Seven patients with augmentation cystoplasty underwent random cold-cup biopsies of ileal segments after a mean period of 14.4 months after cystoplasty and morphological changes were evaluated using light microscopy and transmission and scanning electron microscopy. Most pronounced features were varying degrees of villous atrophy, increased numbers of Paneth and goblet cells. Severity of atrophic villous changes were not related to the length of the interval between surgery and endoscopic biopsy. These findings may be explained as adaptations of bowel tissue to counteract noxious effects of urine and to maintain its epithelial function in the bladder.

Acid-base and electrolyte balance in urinary intestinal orthotopic reservoir: ileocecal neobladder compared with ileal neobladder

OBJECTIVES

To compare acid-base and electrolyte balance in ileocecal and ileal neobladders.

METHODS

Acid-base and electrolyte balance were studied in 45 patients with an ileocecourethrostomy and 18 patients with an ileal reservoir. The mean follow-up was 51 months. Results were compared with regard to both the type of operation and the time since surgery.

RESULTS

No significant differences were found with regard to either the type of operation or the length of follow-up. A preserved renal function is important in maintaining a healthy status.

CONCLUSIONS

The use of 35 to 40 cm of ileum or 10 cm of cecum with the ileocecal junction seems to be safe even after a long follow-up. The length rather than the kind of bowel used for bladder replacement appears to be important in safeguarding hydroelectrolyte and acid-base homeostasis. This is particularly true in the presence of preserved renal function.

Metabolic substrate utilization differs in ileal faecal and urinary reservoirs

BACKGROUND

Construction of an ileal faecal or urinary reservoir profoundly alters ileal luminal ecology and availability of mucosal metabolic substrates. The aims of this study were to measure mucosal metabolic flux of butyrate and glutamine in histologically normal (control) ileum and to determine the effect of reservoir construction on metabolic fluxes in patients with ileal pouch-anal anastomosis and ileocystoplasty.

METHODS

Endoscopic biopsy samples were obtained from normal ileum (n = 10), ileum of patients with ulcerative colitis (n = 10), ileal pouch-anal anastomosis (n = 7), ileocystoplasty (n = 7) and ileal conduit (n = 7). Using a closed microculture technique, biopsy utilization of 14C-labelled butyrate and glutamine was measured as [14C]carbon dioxide production. Biopsy DNA content was measured and [14C]carbon dioxide evolution expressed as picomoles [14C]carbon dioxide per microgram DNA per hour.

RESULTS

The metabolic flux of both butyrate and glutamine was reduced in ileal pouch mucosa compared with that of ileal mucosa in patients with ulcerative colitis. In contrast, the metabolic flux of buyrate alone was reduced in ileal mucosa from ileocystoplasty and ileal conduit compared with that in normal ileal mucosa, while the metabolic flux of glutamine remained unchanged.

CONCLUSION

Ileal mucosal metabolic fluxes measured in vitro are altered by changing luminal ecology in vivo. These changes may affect the health and mucosal integrity of ileum used to construct these reservoirs.

Metabolic complications of urinary diversions: an overview

Patients with urinary diversions present unique challenges to internists who have an important role in their long-term management. Advances in surgical techniques over the past 30 years have given rise to a number of urinary diversion procedures that use various intestinal segments. In its normal function, the intestine absorbs water and solutes. When placed in contact with the urinary stream, the intestine can create numerous metabolic abnormalities. These include bone disease, hepatobiliary disease, infection, malignancy, neurologic complications, nutritional deficiencies, and a number of electrolyte and acid-base disorders. An overview of these metabolic abnormalities and their causes is provided, as well as recommendations for screening and management of patients.

Metabolic complications of continent urinary diversions

The advent of modem reconstructive techniques in urologic surgery has allowed a wide use of intestinal segments in young and older patients. Intestinal conduits and reservoirs can produce a series of complications due to hydroelectrolytic disturbances, alterations of acid-base balance and of bone and hepatic metabolism, intestinal malabsorption. The severity of clinical features depends on the quantity of solute exchanges through the mucosa of the intestinal segment used and on the “age” of the conduit or reservoir.

Effect of urinary intestinal diversion on urinary risk factors for urolithiasis

We investigated the effect of urinary intestinal diversion on risk factors for calcium urolithiasis, such as calcium, phosphate, magnesium, uric acid, oxalate and citrate, in 3 groups of patients (Kock pouch, Indiana pouch and ileal conduit). Mean urinary volume was not significantly different among the 3 groups. Mean serum creatinine and 24-hour creatinine clearance in the continent reservoir group were better than in the ileal conduit group. Mean urinary excretion of calcium, phosphate and magnesium was significantly greater in the continent reservoir group than in the ileal conduit group. Although calcium excretion had a positive correlation with 24-hour creatinine clearance, calcium excretion per ml. per minute creatinine clearance still showed a significant difference. Increased calcium excretion is considered to reflect metabolic disturbances resulting from reabsorption of urinary solutes through the intestinal segments. Overall, there was no significant difference in the urinary parameters between the Kock and Indiana pouch groups. While mean urinary oxalate and citrate were within the normal range in all 3 groups, more than a third of the patients in each group were hypocitraturic (less than 100 mg. per day). In none of the 3 groups did the levels of urinary calcium, phosphate and magnesium, as well as other urinary risk parameters show any correlation with the duration of diversion. In summary, our study indicated that the continent urinary reservoir causes a long-term increase in urinary excretion of calcium, phosphate and magnesium. These urinary metabolic alterations might promote the formation of calcium urolithiasis as well as infectious stones. The degree of metabolic alterations may be greater with a continent reservoir than with an ileal conduit.

Studio delle alterazioni metaboliche dei pazienti sottoposti a neovescica ortotopica di sostituzione e reservoir urinario

Urine exposed to intestinal mucosa changes its composition, as some substances are absorbed and others are secreted. Metabolic effects in 57 patients who underwent bladder substitution, augmentation cystoplasty or continent reservoir, were reviewed in our institute. Hyperchloraemic metabolic acidosis was the most common effect. Even if the consequences are often limited by the body's compensatory response, the risk of long-term complications is always present and a close metabolic follow-up is mandatory.

Continent urinary reservoirs

With the increasing incidence of bladder cancer, many different operations have been devised to reconstruct the lower urinary tract in a continent fashion. The incontinent type of urinary reservoir (ileal conduit) has been a surgical preference for many years. However, the continent urinary reservoir (CUR), neobladder, and rectal bladder offer the capable and motivated patient an alternative to an incontinent permanent stoma. Nursing management of patients requiring diversional surgery requires continual updating of these specialized surgical procedures and unique aspects of care.

The effects of ileocystoplasty on the development of renal failure in a rat model 5/6 nephrectomy

We examined the effects of ileocystoplasty on renal function and bone mineral content in 160 juvenile male Wistar-Furth rats with and without renal insufficiency induced by 5/6 nephrectomy. At intervals up to 20 weeks blood, bone and kidney samples were obtained with the animals under anesthesia and then they were sacrificed. Serum parameters of renal function and calcium metabolism were measured. Samples of bone were analyzed for calcium, magnesium and phosphorus content. At 20 weeks after 5/6 nephrectomy renal function was decreased by approximately half. The decrease in renal function and the changes in renal histology were identical in animals with and without ileocystoplasty. Bone mineral content in the animals with renal insufficiency with or without ileocystoplasty was not different from sham operated animals or from animals with an ileocystoplasty and normal renal function. These studies demonstrate that ileocystoplasty per se does not hasten the progression to renal failure or produce bone demineralization in rats having moderate renal insufficiency.

Urinary diversion: Anatomo-physiological assumptions

The basic anatomical and physiological conditions needed for preparation of a good functioning urinary reservoir are analyzed according to current literature and personal experience. Owing to the need for a schematic and concise exposition, the text has been subdivided under five headings: (I) Metabolic considerations: a) the segment used; b) the duration of contact between intestinal mucosa and urine; c) the size of the exposed intestinal surface. (II) Renal function. (Ill) Physical properties of the reservoir: a) contractility; b) configuration; c) accommodation; d) viscoelasticity. (IV) Carcinogenesis: a) statistical considerations; b) ethiopathogenesis. (V) Clinical consequences of the removal of a normally functioning intestinal segment.

Decreased absorption of 22Na and 36Cl in ileal reservoirs after exposure to urine. An experimental study in patients with continent ileal reservoirs for urinary or fecal diversion

After urinary diversion to intestinal segments, reabsorption of chloride, ammonium, and hydrogen ions occurs, sometimes leading to hyperchloremic acidosis. The mucosa of ileal reservoirs exposed to urine show substantial atrophy, indicating a loss of absorptive capacity. In ten patients with urinary diversion via a continent ileal reservoir, the absorption of [22Na] and [36Cl] was studied after instillation for 15 min into the reservoir of a test solution containing 50 kBq [22Na] and 50 kBq [36Cl]. The activity of the radionuclides was determined in serum samples after 60 and 180 min and the fractions absorbed were calculated. Absorption of the two radionuclides was also calculated by comparison of the activities in samples of the test solution taken before and 15 min after instillation into the reservoir. The same investigations were performed in seven patients with continent ileostomy reservoirs. The study demonstrated a decreased capacity to absorb [22Na] and [36Cl] across the mucosa of the reservoirs exposed to urine compared to the mucosa of those exposed to feces. Due to the transformation of the ileal mucosa after exposure to urine, the risk for development of metabolic disturbances should be minimal after urinary diversion to a continent ileal reservoir.

Continent urinary diversion

From August 1982 through March 1988, 531 patients have undergone continent urinary diversion using an ileal reservoir constructed according to the method of Kock. For the last 18 months we have used the principle of Kock reservoir construction for primary lower urinary tract reconstruction after cystectomy in 39 highly selected male patients by means of a ureteroileal urethrostomy. Early complications occurred in 86 of 531 patients (16.2 per cent), resulting in an operative mortality rate of 1.9 per cent (10 of 531). The early complication rate was 16.5 per cent among patients undergoing 1-stage cystectomy and Kock pouch construction, and 15.2 per cent among patients undergoing Kock pouch conversion. Late complications have been analyzed in 489 patients who have undergone Kock cutaneous diversion. The complications unique to continent urinary diversion, their incidence and the effect of technical modifications in reducing the number of late complications are shown. Note that since the last modification in July 1985 the over-all incidence of late complication has decreased to 22 per cent. Based on this ongoing experience we conclude that the continent ileal reservoir, as conceived by Kock, remains the ideal internal reservoir for bladder replacement in terms of volume accommodation with the lowest internal pressures, and the intussuscepted ileal nipple valve mechanism is a reproducible, highly effective mechanism that prevents reflux and pyelonephritis in greater than 95 per cent of the patients and produces excellent continence. Our enthusiasm remains tempered by the need for reoperation in approximately 10 to 15 per cent of the patients, usually due to a pinhole fistula or false passage at the base of the efferent nipple valve mechanism. Electrolyte abnormalities rarely occur and in the absence of radiation gastrointestinal dysfunction is unusual. Continent urinary diversion is a viable concept that provides a real alternative in terms of quality of life and self-image for the patient who requires urinary diversion for any reason.