No Evidence of Osteopenia 5 to 8 Years After Ileal Orthotopic Bladder Substitution

Why do patients with urinary diversions have an increased risk of bone fracture? A systematic review on risk factors for osteoporosis and bone mineral density loss in this group of patients

INTRODUCTION

Patients undergoing radical cystectomy with urinary diversions (UD) are at increased risk of bone fractures compared to the general population. Although a loss of bone mineral density (BMD) has been described in patients with UD, we still do not know with certainty why these patients follow this tendency.

OBJECTIVE

We performed a systematic review of the available literature to analyze the prevalence of osteoporosis and bone alterations in patients with ileal UD and the possible associated risk factors.

EVIDENCE ACQUISITION

We systematically searched PubMed® and Cochrane Library for original articles published before December 2022 according to PRISMA guidelines.

EVIDENCE SYNTHESIS

A total of 394 publications were identified. We selected 12 studies that met the inclusion criteria with 496 patients included. Six of the twelve studies showed decreased BMD values. Prevalence of osteoporosis was specified in three articles, with values ranging ​​from 0% to 36%. Risk factors such as age, sex, body mass index, metabolic acidosis and renal function appear to have an impact on bone tissue reduction, while type of UD, follow-up, 25-hydroxyvitamin D and parathormone had less evidence or contradictory data. The heterogeneity of the studies analyzed could led to interpretation bias.

CONCLUSIONS

UD are associated with multiple risk factors for osteoporosis and bone fractures. Identifying patients at highest risk and establishing diagnostic protocols in routine clinical practice are essential to reduce the risk of fractures and the resulting complications.

Impact of Intestinal Urinary Diversion on the Risk of Fracture and Loss of Bone Mass: A Systematic Review

BACKGROUND

Patients undergoing intestinal urinary diversion (IUD) may have a higher risk of osteoporosis and risk of fractures due to metabolic acidosis and decrease of intestinal absorption surface.

OBJECTIVE

We performed a systematic review of the available literature on the impact of IUD on bone demineralization.

METHODS

We systematically searched PubMed®, for original articles published before April 2020. Primary end points were the risk of fracture and loss of bone density. Secondary outcomes were the metabolic changes in biochemical and urine parameters related to calcium metabolism and histological changes.

RESULTS

Our electronic search identified a total of 2417 articles. After a detailed review, we selected 11 studies that addressed the impact of IUD on bone health in 10369 patients. The risk of bone fracture was studied in 3 articles, showing a higher risk in the IUD population. Of the 9 articles evaluating the relation between intestinal urinary diversion and bone density, 5 did find a positive association. One article evaluated the bone metabolism at a cellular level after IUD showing a decrease in bone turnover in this population. Three of the eight studies reporting data on serum parameters related to calcium and phosphate metabolism showed differences. Finally, a correlation between concentration of pyridolines in urine and loss of bone density was found in two of the three studies.

CONCLUSIONS

Although published data on BMD are contradictory, patients undergoing IUD seem to be at higher risk of bone fractures. Our finding support the need to implement accessible strategies on osteoporosis screening and prevention in IUD patients.

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.

Bone and metabolic complications of urinary diversions

Hyperchloremic metabolic acidosis is a complication of urinary diversion using ileum or colon. Its prevalence ranges from 25% and 46% depending on the procedure used and renal function of the patient. It is a consequence of intestinal fluid and electrolyte exchange between intestinal mucosa and urine. The main mechanism is absorption of ammonium and chloride from urine. Long-term chronic metabolic acidosis in these patients may lead to impaired bone metabolism and osteomalacia. Regular monitoring of pH, chlorine, bicarbonate, and calcium-phosphorus metabolism is therefore essential for early diagnosis and treatment.

Risk of fracture after radical cystectomy and urinary diversion for bladder cancer

PURPOSE

Radical cystectomy and urinary diversion may cause chronic metabolic acidosis, leading to long-term bone loss in patients with bladder cancer. However, the risk of fractures after radical cystectomy has not been defined. We assessed whether radical cystectomy and intestinal urinary diversion are associated with increased risk of fracture.

PATIENTS AND METHODS

Population-based study using SEER-Medicare-linked data from 2000 through 2007 for patients with stage 0-III bladder cancer. We evaluated the association between radical cystectomy and risk of fracture at any site, controlling for patient and disease characteristics.

RESULTS

The cohort included 50,520 patients, of whom 4,878 had cystectomy and urinary diversion. The incidence of fracture in the cystectomy group was 6.55 fractures per 100 person-years, compared with 6.39 fractures per 100 person-years in those without cystectomy. Cystectomy was associated with a 21% greater risk of fracture (adjusted hazard ratio, 1.21; 95% CI, 1.10 to 1.32) compared with no cystectomy, controlling for patient and disease characteristics. There was no evidence of an interaction between radical cystectomy and age, sex, comorbidity score, or cancer stage.

CONCLUSION

Patients with bladder cancer who have radical cystectomy and urinary diversion are at increased risk of fracture.

Bladder augmentation and urinary diversion in patients with neurogenic bladder: non-surgical considerations

Segments from almost all parts of the bowel have been used for urinary diversion. As a result, the available absorptive surface area of the bowel is reduced, and the incorporation of bowel segments into the urinary tract may have metabolic consequences. This is an area somewhat neglected in the literature. Metabolic complications are rare, but sub-clinical metabolic disturbances are quite common. Several studies have demonstrated that some of the absorbent and secreting properties of the bowel tissue are preserved after incorporation into the urinary tract. Hyperchloraemic metabolic acidosis can occur if ileal and/or colon segments are used, as well as malabsorption of vitamin B(12) and bile acid after the use of ileal segments. These metabolic effects are not as severe as may be suspected and can be prevented by prophylactic substitution. Secondary malignancies can develop as a long-term consequence of bladder augmentation. Using colonic segments, tumours are most likely to occur at the ureteral implantation site. To prevent metabolic complications, careful patient selection and meticulous and lifelong follow up, as well as prophylactic treatment, are mandatory. Endoscopy for early detection has been recommended, starting 10 years postoperatively for patients who underwent surgery for a benign condition.

[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

A consensus conference convened by the World Health Organization (WHO) and the Société Internationale d'Urologie (SIU) met to critically review reports of urinary diversion. The world literature on urinary diversion was identified through a Medline search. Evidence-based recommendations for urinary diversion were prepared with reference to a 4-point scale. Many level 3 and 4 citations, but very few level 2 and no level 1, were noted. This outcome supported the clinical practice pattern. Findings of >300 reviewed citations are summarized. Published reports on urinary diversion rely heavily on expert opinion and single-institution retrospective case series: (1) The frequency distribution of urinary diversions performed by the authors of this report in >7000 patients with cystectomy reflects the current status of urinary diversion after cystectomy for bladder cancer: neobladder, 47%; conduit, 33%; anal diversion, 10%; continent cutaneous diversion, 8%; incontinent cutaneous diversion, 2%; and others, 0.1%. (2) No randomized controlled studies have investigated quality of life (QOL) after radical cystectomy. Such studies are desirable but are probably difficult to conduct. Published evidence does not support an advantage of one type of reconstruction over the others with regard to QOL. An important proposed reason for this is that patients are subjected preoperatively to method-to-patient matching, and thus are prepared for disadvantages associated with different methods. (3) Simple end-to-side, freely refluxing ureterointestinal anastomosis to an afferent limb of a low-pressure orthotopic reconstruction, in combination with regular voiding and close follow-up, is the procedure that results in the lowest overall complication rate. The potential benefit of "conventional" antireflux procedures in combination with orthotopic reconstruction seems outweighed by the higher complication and reoperation rates. The need to prevent reflux in a continent cutaneous reservoir is not significantly debated, and this should be done. (4) Most reconstructive surgeons have abandoned the continent Kock ileal reservoir largely because of the significant complication rate associated with the intussuscepted nipple valve.

Effect of stanford pouch and ileal conduit urinary diversions on bone mineral density and metabolism

After urinary-intestinal diversions metabolic complications may occur in long term follow up. We aimed to evaluate bone metabolism changes in urinary diverted patients. Nineteen patients with urinary diversions (11 Stanford pouch and 8 ileal conduit) performed with diagnosis of locally invasive bladder cancer and 19 age-sex matched healthy subjects were enrolled in the study. Bone mineral density (BMD), arterial blood pH, bicarbonate and base excess as well as bone mineralisation parameters at urine and serum were evaluated for all groups. For statistical evaluation, nonparametric comparisons between groups were used. Comparison of ileal conduit and control groups displayed higher alkaline phosphatase and parathormone levels in the patient group though the difference was not significant. The mean BMD values of ileal conduit group were osteopenic, revealing a significant difference with the control group. Statistically significant differences between alkaline phosphatase, parathormone levels of Stanford pouch and control groups were apparent whereas BMD values were not significantly different. When the two patient groups were compared with each other, no difference in BMD or bone metabolism parameter values could be observed. Patients with urinary diversions are under risk of bone demineralisation and must be followed by BMDs, arterial blood analysis and bone mineral metabolism parameters.

Prophylaxis against bone loss in Kock reservoir patients with reduced glomerular filtration rate

OBJECTIVE

We investigated whether treatment with calcium carbonate and vitamin D3 can improve the bone mineral content of patients with ileal reservoirs for continent urinary diversion and a reduced glomerular filtration rate (GFR).

MATERIAL AND METHODS

Twenty-six patients with Kock reservoirs were included in the study. Bone mineralization was determined using dual-energy X-ray absorptiometry. Kidney function was estimated from Cr-EDTA clearance and serum cystatin C concentration. Osteocalcin and parathyroid hormone in serum were also measured. Patients with reduced GFR were treated with calcium carbonate and vitamin D3 perorally.

RESULTS

Bone mineral density in the femur neck and hip increased in the treatment group, as reflected by an improved T score.

CONCLUSION

Patients with ileal reservoirs for continent urinary diversion and reduced kidney function should be supplemented with calcium carbonate and vitamin D3 in order to reduce the long-term risk of osteoporosis.

Bladder, bowel and bones--skeletal changes after intestinal urinary diversion

Impaired bone metabolism following urinary diversion through intestinal segments has always been a controversial subject of unclear clinical relevance. Whereas the perpetuated pathophysiological considerations seem conclusive in theory, the role of acidosis and malabsorption is less clear in animal experimentation and, even more so, in the clinical reality of modern continent diversion. In hardly any of the available contemporary case series was overt derangement of the acid-base balance, rickets or osteomalacia encountered. No consistent changes in osteotropic serum parameters could be found with normal calcium and phosphate in all patients. The assumption that colonic reservoirs have a higher risk of developing metabolic bone disease could not be confirmed by clinical data. As early correction of base excess is easy and probably a common policy in patients with intestinal urinary reservoirs, it will be virtually impossible to further study the natural history of bone metabolism after urinary diversion. While there is no need for a bone specific follow-up in asymptomatic adults with a normal acid-base balance, particular attention should be paid to children and to all patients with impaired renal function.

Metabolic Evaluation of 94 Patients 5 to 16 Years After Ileocecal Pouch (Mainz Pouch 1) Continent Urinary Diversion

PURPOSE In continent urinary diversion metabolic disturbances may be encountered in long-term followup. We evaluated metabolic consequences in patients with a minimum followup of 5 years after Mainz pouch 1 urinary diversion.

MATERIALS AND METHODS

At our institution continent urinary diversion using the ileocecal segment was performed between 1983 and 1995 in 458 patients. A total of 94 patients with an ileocecal pouch for a minimum of 5 years were reevaluated for metabolic changes. Median followup was 9.0 years. Routine laboratory parameters, blood gas analysis, vitamin B12, vitamin D25, cross-laps, bone specific alkaline phosphatase, osteocalcin and propeptide of type I collagen were obtained. Bone density was measured in 18 patients. Vitamin B12 changes could be followed longitudinally in 24 patients.

RESULTS

Medians of all parameters were in normal ranges. Clinical examinations revealed no signs of megaloblastic anemia, funicular myelosis or osteoporosis. There was no significant decrease of vitamin B12 in the long run. After followup examination we recommended vitamin B12 supplementation in 32% of patients because levels were in the lower normal range or below. A total of 37% of patients continue to take Na+/K+-citrate for prevention of metabolic acidosis.

CONCLUSIONS

Patients with an ileocecal pouch and a followup of more than 5 years did not present with clinical symptoms caused by metabolic disturbances. Nevertheless, systematic followup of blood gases in particular and alkali supplementation may have prevented bone demineralization. Followup of vitamin B12 is of concern because about a third of these patients need supplementation.

The effect of enterocystoplasty on bone strength assessed at four different skeletal sites in a rat model

The objective of the study was to investigate bone strength at four different skeletal sites in a chronic animal model of urinary diversion. Young male Wistar rats (120) were allocated randomly to four groups undergoing ileocystoplasty; ileocystoplasty and resection of the ileocecal segment; colocystoplasty; or sham operation (controls). After 8 months the lumbar vertebrae, femora, and tibiae were harvested at necropsy. Bone strength was assessed biomechanically at four different skeletal sites: vertebra L3, femoral middiaphysis, femoral neck, and distal femoral metaphysis. Bone mass and architecture were assessed using standard static histomorphometry of the proximal tibial metaphysis (trabecular bone volume [BV/TV]; trabecular number [Tb.N]) and ash weight. Statistically significant differences of biomechanical parameters between groups were observed at three skeletal sites with corresponding changes in tibial histomorphometry. Isolated ileocystoplasty resulted in decreased maximum load values of L3 (-16.4%; p < 0.0035) and a substantial reduction in tibial BV/TV (-34.7%; p < 0.05). Ileocystoplasty combined with resection of the ileocecal segment led to a significant loss of bone strength of L3 (-32.4%; p < 0.0015) and a dramatic reduction of tibial BV/TV (-45.9%; p < 0.01). Loss of tibial metaphyseal bone mass was predominantly caused by a decrease in Tb.N. (p < 0.01). Colonic augmentation had no significant effect on bone strength or histomorphometric values. In conclusion, this is the first experimental study to demonstrate the relevance of histomorphometrically proven bone loss after enterocystoplasty in terms of biomechanical variables.

Skeletal growth and long-term bone turnover after enterocystoplasty in a chronic rat model

OBJECTIVE

To investigate skeletal growth and bone metabolism in a chronic animal model of urinary diversion.

MATERIALS AND METHODS

Young male Wistar rats (120) were allocated randomly to four groups undergoing: ileocystoplasty, ileocystoplasty and resection of the ileocaecal segment, colocystoplasty, and controls. All animals received antibiotics for 1 week after surgery; half of each group remained on oral antibiotics. Bone-related biochemistry was measured in serum and urine. Dual-energy X-ray absorptiometry and peripheral quantitative computed tomography (pQCT) were used to determine bone mass ex vivo.

RESULTS

Most (90%) of the rats survived the study period (8 months); six rats died from bowel obstruction at the level of the entero-anastomosis and four had to be killed because of persistent severe diarrhoea. Vital intestinal mucosa was found in all augmented bladders. There were no differences in bone length and volume. Loss of bone mass was almost exclusively in rats with ileocystoplasty and resection of the ileocaecal segment (-37.5%, pQCT, P < 0.01). There was no hyperchloraemic metabolic acidosis or gross impairment of renal function. Hypomagnesaemia, hypocalcaemia and decreased insulin-like growth factor-binding protein 3 were the only significant findings on blood analysis. Deoxypyridinoline crosslinks in urine were higher in rats with an enterocystoplasty than in controls.

CONCLUSIONS

Enterocystoplasty in rats neither impairs skeletal growth nor bone quantity, but leads to significant loss of bone mass when combined with resection of the ileocaecal segment. Rarefaction of the trabecular network is confined to the metabolically highly active cancellous compartment, most likely as a consequence of intestinal malabsorption.

Urinary diversion: ileal conduit to neobladder

PURPOSE

The goals of urinary diversion have evolved from simply diverting the urine through a conduit to orthotopic reconstruction, which provides a safe and continent means to store and eliminate urine with efforts to provide an improved quality of life. We address meaningful points that may help optimize clinical results in patients with an orthotopic bladder substitute.

MATERIALS AND METHODS

The review involved an objective evaluation of the basic science literature of functional, structural and physiological characteristics of gastrointestinal tissue as a substitute for bladder. Potential problems that may be associated with particular parts of the gut for use in reconstruction are discussed. We also summarize the clinical results and complications of orthotopic reconstruction.

RESULTS

In the last 10 years the paradigm for choosing urinary diversion has changed substantially: In 2002 all patients undergoing cystectomy were neobladder candidates. It is critically important to understand the phenomenon of maturation. The motor and pharmacological response of the implanted gut changes dramatically toward that of the bladder. Structural and ultrastructural changes in the ileal mucosa lead to a primitive epithelium similar to urothelium. The need for reflux prevention is not the same as in ureterosigmoidostomy conduit or continent diversion. Reflux prevention in neobladders is even less important than in a normal bladder. When using nonrefluxing techniques, the risk of obstruction is at least twice that after direct anastomosis. Kidney function is not impaired by diversion if stenosis is recognized and managed. Patient health status is more influenced by underlying disease than by diversion. Complications of neobladders are actually similar to or lower than the true rates after conduit formation, in contrast to the popular view that conduits are simple and safe. Some degree of nocturnal leakage is a consistent finding in most reports despite a technically sound operation. The precise pathogenesis of urinary retention requiring clean intermittent catheterization remains uncertain. There are new complications, such as neobladder rupture and mucous tamponade.

CONCLUSIONS

Orthotopic reconstruction has passed the test of time. In these patients life is similar to that in individuals with a native lower urinary tract. Until a better solution is devised orthotopic bladder reconstruction remains the best option for patients requiring cystectomy.

Growth and metabolic consequences of bladder augmentation in children with myelomeningocele and bladder exstrophy

OBJECTIVE

Bladder augmentation using intestinal segments is reported to cause decreased linear growth in bladder exstrophy and myelomeningocele patients. We studied changes in calcium metabolism, height, bone chemistry, and bone density in exstrophy and myelomeningocele patients after bladder augmentation.

METHODS

Thirty-three patients were prospectively admitted to the Pediatric Clinical Research Center at the University of California San Francisco for 24 hours. Blood and urine were analyzed for electrolytes, and serum was obtained for markers of calcium metabolism. Dual radiograph bone densitometry of the forearm was performed. Myelomeningocele patients were compared with nonaugmented myelomeningocele patients matched by age, gender, level of defect, and ambulatory status. Exstrophy augmented patients were compared with nonaugmented exstrophy patients. The bone densities in both groups were compared with normal children. Laboratory values and percentile heights were statistically analyzed using the Student t test; bone densitometry was analyzed using the Tukey test.

RESULTS

Twenty-two patients with myelomeningocele and 11 with bladder exstrophy were studied. Mean follow-up was 3.7 years postaugmentation (range: 1-13 years). The results indicate a significant difference in serum bicarbonate and chloride levels between myelomeningocele patients who underwent ileal augmentation and those who did not. Although this may be indicative of chronic metabolic acidosis, there was no affect on growth or bone density when compared with controls. There were no other significant differences in laboratory values, or percentile heights, nor were any differences noted in patients who underwent gastrocystoplasty. In the exstrophy group, there were no observable differences in percentile height or laboratory values between the augmented and nonaugmented group. There were no significant differences in bone density between these 2 groups when matched for age and gender. No significant difference was seen in bone density when these groups were compared with normal children.

CONCLUSION

Bladder augmentation is safe and does not impact negatively on the linear growth or bone densities of patients with myelomeningocele or bladder exstrophy.

Stone risk after bladder substitution with the ileal-urethral Kock reservoir

OBJECTIVE

The study was carried out to compare urinary biochemical and physicochemical environments in patients who had undergone bladder substitution with the ileal-urethral Kock reservoir, and who had no actual urinary infection, with those of healthy subjects.

MATERIAL AND METHODS

The participants were 23 male patients who had undergone bladder substitution with the ileal-urethral Kock reservoir and 25 healthy men. All subjects had sterile urine at the time of urine collection. Concentrations of calcium, magnesium, phosphorus, creatinine, citrate, oxalate, and ammonia in 24-h urine samples were measured. Estimates of ion activity products of calcium oxalate (CaOx), calcium phosphate (CaP), brushite (Bru), and magnesium ammonium phosphate (MAP) in urine were calculated according to Tiselius.

RESULTS

There was no significant difference in 24-h urinary volume between patients with a bladder substitute and the healthy controls. For most of the other measured values the results for patients differed significantly from those for controls. The most striking findings were markedly lower urinary excretion rates of citrate (p < 0.0001) and higher urine pH (p < 0.0001) in patients compared with controls. These findings were reflected in significantly higher levels of urinary supersaturation with respect to CaOx (p < 0.0001), CaP (p <0.0001), Bru (p < 0.0001) and MAP (stuvite) (p < 0.0001) in patients with a bladder substitute compared with healthy subjects.

CONCLUSIONS

Hypocitraturia seems to be the main risk factor for calcium stone formation in non-infected Kock reservoir patients, and citrate supplementation appears to be the most obvious choice for stone prophylaxis in patients with intestinal urinary diversion and recurrent renal stone formation.

Determinants of bone loss in patients with Kock ileal urinary reservoir

The purpose of the present study was to determine the change in bone mineral density (BMD) measured with dual energy X-ray absorptiometry (DXA) in patients with Kock reservoirs for urinary diversion who were examined with the same technique 3 years earlier, and relate the changes to kidney function and variables reflecting bone metabolism. A total of 28 patients with Kock ileal reservoirs to the skin (23) or urethra (5) were reinvestigated 3 years after the first measurement. BMD was measured in the lumbar spine, femur and whole body with DXA. Bone specific alkaline phosphatase, osteocalcin, parathyroid hormone (PTH), calcitonin and chloride were also determined in serum. GFR was determined from the plasma clearance of 51Cr-EDTA. The mean values for BMD expressed in percentage of corresponding mean values for age-matched controls (BMD%) were almost identical after 3 years. Only osteocalcin levels correlated with the BMD% values. However, significant positive correlations were found between GFR and the observed individual changes in BMD% over the 3 years in spite of the fact that most GFR values were fairly normal. Enhanced bone loss was associated with high concentrations of osteocalcin and bone specific alkaline phosphatase. Comparisons with blood gas analyses and determination of 1,25 dihydroxyvitamin D performed in the previous study indicate to us that the relation between reduced GFR and low mineral content might, in part, be related to a low-grade metabolic acidosis and reduced availability of the biologically active vitamin D hormone. The conclusion to be drawn is that urinary diversion with a Kock reservoir does not regularly cause bone demineralization. However, patients with even moderately reduced GFR appear to be at risk for developing osteoporosis in the long-time run.

Whole-body potassium and bone mineral density up to 30 years after urinary diversion

OBJECTIVES

To evaluate the long-term effects of different types of urinary diversion on skeletal bone density and whole-body potassium content in patients with an early correction of base excess (< -2.5).

PATIENTS AND METHODS

The early correction of base excess (< -2.5) is one of the principles of the treatment of patients undergoing urinary diversion at our institution. In 27 patients with urinary diversion, bone mineral density (assessed by dual-photon absorptiometry), whole-body potassium, electrolyte and creatinine levels were determined, and capillary blood gas analysed. The mean time since surgery was 16.8 years in 16 patients with a rectal reservoir, 20.5 years in six patients with a colonic conduit, 7.8 years in four patients with an ileocaecal pouch and 5 years in one adolescent with an ileal bladder augmentation.

RESULTS

Bone mineral density was normal in 25 of the 27 patients; no exact measurement was possible in the remaining two. The whole-body potassium content was reduced in eight of the 27 patients (three with a conduit, two with a rectal reservoir, two with an ileocaecal pouch and one with ileal augmentation). In four of these eight patients the base excess was < -2.5 (-2.7 to -5). Of the other four, two had no regular testing of their base balance and two were obese. The electrolytes were within the normal ranges. None of the patients had hyperchloraemic metabolic acidosis.

CONCLUSION

With early correction of the base excess (< -2.5), there was no decrease in bone mineral density and no hyperchloraemic acidosis. There was no significant difference between the different types of urinary diversion. There seems to be a relationship between low base excess and decreased whole-body potassium.

Ileal orthotopic bladder substitutes. What we have learned from 12 years' experience with 200 patients

The perfect bladder substitute has not been devised yet. The ileal orthotopic bladder substitute, however, provides adequate capacity, convenient voiding patterns, optimal continence rate, preservation of renal function, acid-base balance, and calcium metabolism. The authors describe important surgical details based on experience with more than 200 patients. To achieve a good functional result, patient selection, postoperative voiding reeducation, and meticulous follow-up are important.