Metabolic complications of urinary intestinal diversion

Long-Term Evaluation of Metabolic Profile and Bone Mineral Density After Ileocystoplasty in Children

PURPOSE

We evaluated the long-term effects of ileocystoplasty on linear growth, serum electrolytes, acid-base profile and bone mineral density (BMD) in a group of neurologically intact children with a mean followup of 8.9 years.

MATERIALS AND METHODS

Between 1988 and 1997, 9 girls and 16 boys with a mean age of 6 years (range 1 month to 14 years) underwent ileocystoplasty for etiologies other than myelomeningocele and neuropathic bladder. Indications for ileocystoplasty were small noncompliant bladder secondary to bladder exstrophy in 12 cases, bladder outlet obstruction in 10 and post-partial cystectomy for rhabdomyosarcoma in 3. All patients underwent clinical evaluation, supine height measurement, serum electrolytes, arterial blood gases and BMD measurement using a fan beam dual energy absorpitometry scan. BMD was measured at L1-L4 and corrected for age and sex.

RESULTS

Followup ranged from 4 to 13 years (mean 8.9). Serum creatinine was normal in 20 of the 25 patients. All patients had normal supine height measurement with a mean of 45th (+/- 9) centile on growth charts. Serum electrolytes, calcium, phosphorus and arterial blood gases were normal in all patients. Mean BMD corrected for age and sex was 89 (+/- 10)%. BMD was normal in 17 of 25 (68%) patients. Mild reduction in bone density between 1 and 2 standard deviations below the age/sex mean was documented in 3 (12%) patients and the remaining 5 (20%) showed marked osteopenia of 2 or more standard deviations. Of the latter 5 patients 2 had increased serum creatinine, 1 had a history of radiotherapy for pelvic rhabdomyosarcoma and 2 had cloacal exstrophy and short bowel, all of which might have contributed to the osteopenia.

CONCLUSIONS

Ileocystoplasty for children with normal kidney function is not associated with alterations in serum electrolytes or arterial blood gases in the long term. However, 32% of patients showed variable degrees of reduction in BMD. Although marked reduction in BMD was associated with cofactors, 12% of patients had evidence of mild osteopenia in absence of those cofactors. We recommend routine preoperative and longitudinal followup BMD measurements for children undergoing intestinal bladder augmentation.

Metabolic findings after colocystoplasty in children

OBJECTIVES

To investigate whether colocystoplasty has resulted in metabolic changes in the growing child during long-term follow-up according to whether cecum with ascending or sigmoid colon was used.

METHODS

Twenty-eight patients (mean age at surgery 11 years) were included in the study and divided into two groups: group 1, cystoplasty with cecum and ascending colon (12 patients) and group 2, sigmoid cystoplasty (16 patients). Patients' linear growth, body mass index, and the following parameters were estimated before surgery and at 3, 6, and 12 months, and then yearly after surgery: blood and urine electrolytes (sodium, potassium, chloride, calcium, phosphorus, magnesium), creatinine, urea, blood gases, blood pH, urine pH, and blood alkaline phosphatase (ALP). All the data were statistically analyzed.

RESULTS

In group 1, the blood ALP increased significantly (P = 0.026) during follow-up. Severe metabolic acidosis with or without hyperchloremia was found in 7 patients. In group 2, the serum sodium and serum calcium levels decreased significantly (P = 0.014 and P = 0.003, respectively); however, the blood ALP, urine sodium, and urine phosphorus levels increased significantly (P = 0.033, P = 0.027, and P = 0.026, respectively) during follow-up. A statistically significant decrease in blood pH (P = 0.022) was found after surgery. Severe metabolic acidosis with or without hyperchloremia was detected in 5 patients. The average linear growth decreased significantly (P = 0.001 and P = 0.016, respectively) 1 and 2 years postoperatively.

CONCLUSIONS

The statistically significant increase in blood ALP and decrease in serum calcium indicate bone demineralization after colocystoplasty. Our investigations in children suggest that bone demineralization is more frequent after sigmoid cystoplasty than after the use of cecum and ascending colon.

The use of silver nitrate for chemical de-epithelialization and urothelialization of intestine in a rabbit model of augmentation cystoplasty

Urinary tract reconstruction using bowel segments can result in complications such as electrolyte abnormalities, infections, stones and cancer. Intestinal mucosa is the primary site responsible for these complications. De-epithelialization of the mucosa and subsequent urothelialization might alleviate these problems. We recently reported our success in de-epithelialization and subsequent uroepithelialization of intestinal segments using 10 g/100 ml AgNO(3) solution in a rat model of augmentation. In this study, chemical de-epithelialization of a colonic segment was attempted using 10 g/100 ml AgNO(3) solution in a rabbit model of augmentation. Sigmoid cystoplasty was performed in 20 male New Zealand rabbits using a 6 cm patch of sigmoid colon. There were two groups, including one group of five rabbits (control, group 1) that underwent augmentation alone, while another group (15 rabbits, treatment group or group 2) was treated with 10 g/100 ml AgNO(3 )solution before augmentation. Control rabbits were killed at the week 8 of experimentation. Treatment rabbits were killed at 2-, 4-, 6- and 8-week intervals. Immediately before augmentation and at the end of the 8 week experimental period each rabbit underwent cystometry. De-epithelialization of the bowel epithelium without urothelialization was apparent in the treatment rabbits killed at 2 and 4 weeks. Histological analysis revealed almost complete urothelialization of the augmented sections treated with 10 g/100 ml AgNO(3 )solution at the end of the 6 and 8 week of experimental periods. The preoperative and postoperative bladder capacities increased substantially in all groups. There was no obvious histologic difference in the amount of collagen present in the augmented tissues in any of the experimental groups. The present study confirmed that the treatment of intestinal segments with 10 g/100 ml AgNO(3 )solution led to chemical de-epithelialization and urothelialization of the augmented segments. This procedure could, theoretically, have applications to human surgery.

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.

Ureteral tissue balloon expansion for laparoscopic bladder augmentation: survival study

BACKGROUND AND PURPOSE

The search for the perfect urinary bladder substitute continues. Despite their inherent limitations, intestinal segments remain the commonest material for bladder reconstruction. The ureter, with its transitional epithelium, may be the ideal tissue to augment the bladder. Ikeguchi et al reported the feasibility of chronic ureteral balloon expansion by open surgery (J Urol 1998;159:1665). Herein, we propose a completely minimally invasive approach to balloon overdilate a segment of juxtavesical ureter incrementally and to use this in-line tissue-expanded ureteral patch to augment the bladder laparoscopically.

MATERIALS AND METHODS

In five female pigs, a novel ureteral expansion balloon device (Microvasive, MA) was inserted percutaneously and advanced antegrade into the juxtavesical ureter. The device has two channels: one for balloon inflation and the other for draining the kidney. After progressive ureteral expansion over a 3- to 4-week period, laparoscopic augmentation ureterocystoplasty was performed. Animals were euthanized at 15 days (N = 1), 1 month (N = 1), 2 months (N = 1), and 3 months (N = 2).

RESULTS

Percutaneous balloon device placement was technically successful in all five cases (mean operating room time 52 minutes). The mean volume of the tissue-expanded ureter at 1, 2, and 3 weeks was 12.9 cc, 60.3 cc, and 171.8 cc, respectively. Laparoscopic augmentation ureterocystoplasty with (N = 3) or without (N = 2) concomitant subtotal cystectomy was technically successful in all five cases without any open conversion. The mean operative time was 126.5 minutes, and the mean blood loss was 29 mL. Postoperative complications consisted of one case each of pyelonephritis and ureteral stricture. At autopsy, the mean capacity of the bladder was 574 mL, and the P(ves) at maximum capacity was 14 cm H(2)O. Histologic examination of the tissue-expanded ureter revealed regenerated transitional epithelium and muscle hypertrophy.

CONCLUSIONS

Chronic ureteral tissue expansion can be carried out safely and efficaciously. The expanded tissue is thick, healthy, and vascular, with histologic features of normal transitional epithelium and muscle hypertrophy and hyperplasia. This expanded ureteral tissue can be used to augment the bladder with laparoscopic techniques. Such augmented bladders do not show significant shrinkage and possess urodynamic characteristic of normal capacity and normal compliance over a follow-up of 3 months.

Aerosol transfer of bladder urothelial and smooth muscle cells onto demucosalized colonic segments: a pilot study

PURPOSE

We developed a cell transfer technology for covering demucosalized colonic segments with bladder urothelium. This covering would be achieved through aerosol spraying of single cell suspension of bladder urothelial and smooth muscle cells with fibrin glue onto the demucosalized colonic segments.

MATERIALS AND METHODS

In 6 piglets (20 kg.) a 4 cm.2 area of bladder was excised. Single cell suspension of bladder urothelial and smooth muscle cells was prepared. A segment of detubularized sigmoid colon was isolated on its vascular pedicle and demucosalized. The single cell suspensions were combined with an equal volume of fibrin glue and sprayed over the raw submucosal surface of the sigmoid segment. The sigmoid segment was retubularized and sutured to the posterior peritoneum. Animals were sacrificed 4 weeks later, and the segment was submitted to histological and immunohistochemical analysis.

RESULTS

Sigmoid segments appeared grossly intact with no reduction in surface area. Hematoxylin and eosin architecture revealed an intact urothelial layer. Deep to this layer was a randomly aligned but distinctly segregated layer of smooth muscle cells. The urological new smooth muscle layer stained positive for calponin and the urothelial layer was cytokeratin-7 and uroplakin III positive.

CONCLUSIONS

Separation, cell suspension and aerosol delivery of bladder urothelial and smooth muscle cells in fibrin glue can successfully transfer these urological cell populations to a new host tissue commonly used in urological reconstruction. In vivo co-culture of bladder smooth muscle and urothelial cells results in coverage of a large area of demucosalized gut providing new potential for transfer and reconstitution of urologically functionally appropriate tissue to the bladder itself.

Characterization of Escherichia coli strains causing urinary tract infections in patients with transposed intestinal segments

PURPOSE

Transposition of intestinal segments into the urinary tract predisposes to urinary tract infections. We characterized bacterial infections in these patients and examined the virulence genotype and persistence of Escherichia coli isolates.

MATERIALS AND METHODS

We followed 26 patients who underwent bladder reconstructive surgery using transposed intestinal segments. E. coli strains isolated from the urine of these patients were genotyped for established virulence determinants and the frequency of carriage was compared with E. coli strains isolated from community acquired urinary infections and the fecal flora of anonymous volunteers. A longitudinal study of E. coli strains in 9 patients was also done using pulsed field gel electrophoresis.

RESULTS

E. coli was the most frequently isolated organism, responsible for 59% (62 of 105) of monobacterial infections. Other bacteria isolated included Klebsiella species, Proteus species and Enterococcus faecalis. Community acquired E. coli strains were more likely to carry multiple determinants for particular adhesins (P and S fimbriae) and toxins (alpha-hemolysin and cytotoxic necrotizing factor) than fecal strains. Carriage frequency for bladder reconstruction strains was intermediary and not significantly different. The key finding was that E. coli strains persisted for prolonged periods, including 2 years in certain patients, often despite various antimicrobial treatments.

CONCLUSIONS

This study highlights that further steps must be taken to prevent and treat urinary tract infections in this susceptible group. Particular attention should be given to the treatment of persistent infections.

Intermediate effects of the ileocaecal urinary reservoir (Charleston pouch 1) on serum vitamin B12 concentrations: can vitamin B12 deficiency be prevented?

OBJECTIVE

To assess the long-term effects of a form of ileocolic urinary reservoir (Charleston Pouch 1) on vitamin B12 serum levels, as vitamin B12 deficiency may be an important long-term risk after urinary diversion by this method.

PATIENTS AND METHODS

The study included 60 patients (mean age 52 years, range 27-77; 33 men and 27 women) who had a follow-up of >or= 36 months (36-132 months) after the construction of an ileocaecal urinary reservoir. Vitamin B12 serum levels were determined at the time of diversion and again when the patients were evaluated every 6 months.

RESULTS

Fifty-eight patients had a normal serum vitamin B12 concentration before surgery (two patients were excluded from the study because they had low levels); the mean level was 464 pg/mL (normal range 247-1000). At 6 and 12 months, the mean vitamin B12 levels were 367.5 and 468.5 pg/mL; at 1.5, 2, 3, 4, 5, 6, 7, 8, 10 and 11 years, the mean levels were 305, 495.5, 436.5, 379.5, 423.5, 393, 529.5, 631, 333.5 and 340 pg/mL, respectively.

CONCLUSION

Ileocaecal urinary reservoirs have no adverse effects on serum vitamin B12 levels for up to 10 years after surgery. Patients with vitamin B12 deficiency must be identified and given adequate parenteral doses for life. Because body stores of vitamin B12 may not be depleted for many years, problems with B12 may be masked for a long time. We recommend that vitamin B12 levels be obtained annually, that a modest supplement twice yearly (by injection) may be beneficial and that serum vitamin B12 must be sampled before giving vitamin B12 injections, to avoid false results.

Tissue engineering in urology: where are we going?

Tissue engineering in urology is a broad term used to describe the development of alternative tissue sources for diseased or dysfunctional native urologic tissue. This article reviews the recently published techniques involving synthetic and natural biodegradable matrices alone, known as "unseeded" scaffolds, and the latest data on "seeded" scaffolds, which are impregnated with cultured cells from urologic organs. Recent discoveries in reporter gene labeling of urologic tissue are discussed as a new method to identify and track the fates of these transplanted cells in vivo. This article also investigates how these bioengineering techniques are applied to synthetic and natural scaffolds, such as polyglycolic acid and porcine small intestine submucosa, to increase bladder capacity, repair urethral strictures, and replace corporal plaques in Peyronie's disease. Furthermore, recently published reports that these materials have been seeded with chondrocytes to create corporal rods for penile prostheses and stents for ureteral and urethral stricture disease are discussed. With these latest developments as a foundation, the future directions of tissue engineering in urology are presented.

Continent urinary diversion and the exstrophy-epispadias complex

PURPOSE

The use of continent urinary reservoirs has gained wide acceptance, particularly in urinary reconstruction in children with a small capacity or neuropathic bladder. When augmentation cystoplasty is combined with clean intermittent catheterization, patients are often able to achieve continence with low intravesical filling pressures and renal preservation. Often this approach requires fashioning a continent cutaneous stoma, which remains the most challenging aspect of continent urinary reservoirs. We analyzed our experience with continent diversion in patients with exstrophy-epispadias to determine complications and long-term results.

MATERIALS AND METHODS

We performed a retrospective database review of 704 cases of exstrophy-epispadias. Medical records were then used to identify those patients who had undergone creation of a continent urinary reservoir. Charts were reviewed to determine initial diagnosis, augmentation technique, continence mechanism, age, preoperative and postoperative bladder capacity, continence status and complications.

RESULTS

Of the 91 patients identified (68 male, 23 female) who had undergone continent urinary diversion classic bladder exstrophy was present in 80, cloacal exstrophy in 8, complete male epispadias in 2 and female epispadias in 1. The most common techniques for augmentation and continent diversion were ileocystoplasty (41 patients [45%]) and sigmoid cystoplasty (30 [33%]), respectively. Appendix was used in 67 patients (74%) and variants of the Mitrofanoff procedure using segments of tapered ileum or ureter were used to create a continent stoma in 10 (11%). Bladder neck transection was performed in 59 patients (65%). Mean age at augmentation and continent diversion was 8 years (range 2 to 25), with a mean preoperative bladder capacity of 77 cc (15 to 220). Mean followup was 6 years (range 6 months to 12 years). Of the 91 patients 85 (93%) were continent with clean intermittent catheterization per stoma. Of these 85 patients 13 required anticholinergics and alpha-agonists to achieve continence. Six patients (7%) were incontinent after the procedure. Analysis of bladder capacity measurements after augmentation and continent diversion revealed that mean postoperative volume and mean volume increase were 404 cc (range 250 to 640) and 524%, respectively. The most common complications were bladder stone formation (24 patients [26%]) and stomal stenosis (21 [23%]). Bladder stones recurred in 9 patients and stomal stenosis in 3. Other less common complications were vesicourethral fistula (3 patients) and a small bladder perforation (2).

CONCLUSION

Augmentation and continent diversion procedures can increase the functional capacity of the small contracted noncompliant exstrophic bladder, and allow the vast majority of patients to achieve continence and preserve renal function. Bladder calculi and stomal stenosis pose the most significant long-term complications in these patients.

Urinary diversion after radical cystectomy

At most centers with experience in urinary diversion, an orthotopic urinary reservoir is the diversion of choice after radical cystectomy for bladder cancer. The paradigm has shifted in the past 10 years from actively looking for reasons to do an orthotopic diversion to carefully considering why a patient cannot undergo reconstruction to their native urethra. In our institution, any patient who is to undergo a radical cystectomy for bladder cancer is a potential candidate for orthotopic diversion provided they do not have chronic renal insufficiency. In addition, they must have a negative urethral margin on frozen section at the time of cystectomy, and have the mental and physical capacity to understand what is required to manage the reservoir after surgery. Proper patient selection is the key to success. Notably, chronologic age is not an absolute contraindication to orthotopic diversion. Instead, careful consideration of the patient's comorbid conditions should guide eligibility. In addition, locally advanced disease is not a contraindication to an orthotopic diversion. To have the flexibility to manage whatever situation presents itself intraoperatively, the surgeon performing a urinary diversion after radical cystectomy must be facile with several diversion techniques. At the very least, the surgeon must be comfortable with one type of each major form of urinary diversion, a conduit (incontinent) diversion, a continent cutaneous diversion, and an orthotopic diversion. As a result, radical cystectomy and urinary diversion should be performed at centers with significant experience in all three types of diversions.

Ureterocystoplasty (bladder augmentation) with a solitary kidney

Children who develop end-stage renal disease (ESRD) as a result of obstructive uropathies require evaluation and treatment of associated bladder dysfunction to ensure a good outcome following renal transplantation. Bladder dynamics can often be optimized medically, although surgical intervention is occasionally necessary. For those patients who require bladder augmentation, the use of a dilated native ureter (ureterocystoplasty) is preferred to the more commonly used intestine or stomach (enterocystoplasty), which carry a higher risk of complications. Unfortunately, most patients do not have a suitable anatomy for ureterocystoplasty and, by necessity, intestine or stomach has to be utilized. Herein, we describe the successful application of ureterocystoplasty in the presence of ESRD and a solitary kidney prior to renal transplantation. We believe that owing to the many advantages of native urothelium, every effort should be made to use ureter and avoid the use of intestine.

Bone mineral content and related biochemical variables in patients with ileal bladder substitution and colonic Indiana pouch

OBJECTIVES

To evaluate the effects of ileal bladder substitution or colonic Indiana pouch on skeletal bone density and various biochemical parameters related to bone metabolism.

PATIENTS AND METHODS

In 27 patients with urinary diversion and 14 controls with benign urologic disease, bone mineral density (BMD), assessed by dual-photon absorptiometry; serum electrolyte, creatinine, alkaline phosphatase and parathyroid hormone levels were determined, and capillary blood gas analysed. BMD was measured in the lumbar spine and the femur neck. The mean time since surgery was 33.6+/-10.1 months in 17 patients with an ileal bladder substitution and 56+/-9.1 months in 10 patients with a colonic Indiana pouch (p=0.001).

RESULTS

Although BMD did not change in the colonic Indiana pouch group, it was reduced in the patients with ileal bladder substitution compared to control group. The mean pH value was not statistically significant different in the both groups from the control group (p>0.2). The mean base excess value reduced in the substitution group (p<0.01). While alkaline phosphatase levels increased in both groups compared to control group (p<0.05), the mean parathyroid hormone level decreased only in the patients with ileal bladder substitution (p<0.05). The other biochemical parameters were similar in patients and control subjects. There was a statistically significant correlation between the base excess values and BMD values of the patients in both groups.

CONCLUSION

Although there is decreased BMD in patients with an ileal bladder substitute, there is no change in BMD in the patients with Indiana pouch. Alkaline phosphatase levels increased in both patient groups indicating increased bone turnover.

Future trends in bladder reconstructive surgery

The incorporation of bowel into the urinary tract is associated with significant long-term complications. Therefore, considerable efforts are being made to avoid the use of enteric epithelium in bladder reconstruction. The simplest of these entail the use of native urothelium that is already available, with techniques such as auto-augmentation, auto-augmentation de-epithelialized enterocystoplasty, and ureterocystoplasty. Unfortunately, in many patients, the bladder is too small, or dilated ureters are not available, and these techniques cannot be applied. Recently, experimental techniques are examining the use of tissue expansion to the ureter and bladder to increase the volume of tissue available. Tissue engineering techniques are being applied to bladder regeneration, and considerable advances have already been made leading to in vivo animal experimentation, the results of which are very encouraging. The details of these most recent advances will be discussed in detail in this report.

Ureteral segmental replacement using multilayer porcine small-intestinal submucosa

PURPOSE

To assess the outcome of segmental ureteral replacement using a new multilayer porcine small-intestinal submucosa (SIS), Surgisis ES (Cook Inc., Stouffville, ON, Canada) designed to provide enhanced strength.

MATERIALS AND METHODS

The ureters of five female farm pigs were accessed through a median laparotomy incision. A segment of 2-cm midureter was resected bilaterally. The left ureteral segments were replaced by 10F tubularized SIS segments using 5-0 PDS interrupted sutures. The right ureters were primarily end-to-end anastomosed, serving as controls. Internal pigtail stents were left bilaterally for 6 weeks. One animal at 3 weeks, one animal at 6 weeks, and three animals at 12 weeks were sacrificed. The patency of the ureters was assessed by retrograde pyelography at 6 and 12 weeks, while inflammation and regeneration were assessed grossly and histologically.

RESULTS

At 3 and 6 weeks, both experimental and control ureters were patent without extravasation on retrograde studies. Adhesions and signs of ureteral inflammation were found only on the SIS side. The graft was partially and completely epithelialized at 3 and 6 weeks, respectively. However, at 12 weeks, all the ureters on the experimental side were completely occluded, while on the control side, all were patent. Although histologically, urothelium and muscular cells had proliferated over the graft, they were embedded in an intense fibrotic and inflammatory process. At 12 weeks, all animals had developed hydroureteronephrosis above the grafts.

CONCLUSIONS

Technically, Surgisis ES was easily modeled, providing conditions for a water-tight anastomosis. None of the animals developed urinary fistula. Regeneration of urothelium and muscle were induced and supported by the graft. However, functional replacement was not successful. A suitable material for this purpose has yet to be discovered.

Vitamin B12 and folate after 5-12 years of continent ileal urostomy (Kock reservoir) in children and adolescents

OBJECTIVE

To assess B12 and folate deficiency after continent urinary diversion via a Kock continent urinary reservoir in children and adolescents.

METHODS

Ten boys and 10 girls (10.8-18 years old at surgery) were operated with a Kock reservoir and followed for 5-12 years (mean 8.5). The follow-up period was divided into early (3 months-5 years, EFU) and late (5-12 years, LFU) follow-up. Patients were investigated for haemoglobin, serum iron, total iron binding capacity (TIBC), serum Vitamin B12, serum and blood folate, methylmalonic acid (MMA), homocystine and glomerular filtration rate.

RESULTS

Two patients developed subnormal B12 values (median 107.5 pmol/l), one at the EFU, and the other at LFW. The B12 value decreased during the LFU compared to the EFU in nine patients, but it was still within the normal range. Two patients with renal impairment had elevated MMA with normal B12 values. Five patients had high values of homocystine with folate deficiency and/or B12 deficiency and renal impairment. Plasma folate mean value was normal during the whole follow-up. Blood folate was below normal in five patients at the EFU. Two of these five patients, in addition to three patients, had low values at the LFU. Three of four patients with remaining short terminal ileum (20-45 cm) had normal B12 values at both the EFU & LFU and one had low values at the LFU. Six patients had subnormal GFR at the LFU.

CONCLUSIONS

To a similar degree as in adults, Vitamin B12, folate and iron deficiency can occur in children and adolescents after continent urinary diversion using an ileal segment. Therefore, Vitamin B12 and folate should be monitored regularly in these patients. Serum MMA and homocystine may offer increased detection of Vitamin B12 deficiency, especially in the patients with normal renal function. Vitamin B12 deficiency is neither correlated with the time elapsed since surgery, nor with the ileum length. Patients are usually asymptomatic, so patients with true B12 deficiency should be identified and placed on life-long Vitamin B12 therapy. An adequate synthetic folic acid as supplements or fortified food is recommended for patients with folate deficiency.

Augmentation ileocystoplasty in patients with neurogenic bladder due to spinal cord injury or spina bifida

STUDY DESIGN

Retrospective analysis of augmentation ileocystoplasty for neurogenic bladder.

OBJECTIVES

To analyze the effects and complications of augmentation ileocystoplasty in patients with neurogenic bladder due to spinal cord injury (SCI) or spina bifida retrospectively.

SETTING

Department of Urology, Kanagawa Rehabilitation Hospital, Japan.

METHODS

We have treated 11 patients with neurogenic bladder due to SCI and 10 patients with spinal bifida with augmentation ileocystoplasty since 1989. The purpose of the treatment was to stop vesicoureteral reflux (VUR) and/or amelioration of urinary incontinence. In 17 of 21 cases, the antireflux operation was received simultaneously. All cases performed clean intermittent self catheterization postoperatively.

RESULTS

Urinary incontinence improved in all cases and only transient recurrence of VUR was observed in the follow-up term. Complications occurred in patients with SCI, but they could be treated conservatively.

CONCLUSION

Augmentation ileocystoplasty is a good treatment option for contracted bladder or VUR, which occurs in patients with neurogenic bladder.

New surgical techniques in pediatric urology

More sophisticated endoscopic instruments, combined with a better understanding of bladder and urethral pathology, have significantly improved the therapeutic approaches for both posterior urethral valves and ureteroceles. New generation lithotripters have allowed for a safe and efficient method of treating urinary calculi in children, which was once thought too injurious a process with first-generation machines. The rapidly advancing field of laparoscopy, aided by the development of more optically refined and diminutive instruments, has allowed for its application in a wide variety of surgical interventions in pediatric urology. The tubularized incised plate urethroplasty has challenged more traditional approaches to hypospadias repair and is now considered by many pediatric urologists to be the best approach for midshaft and distal hypospadias. The one-stage approach to exstrophy repair may hold the answer to improved continence without a formal bladder neck reconstruction. Finally, the field of tissue engineering leads the way to new advances in autologous biological substitutes in the surgically-challenged patient where there is a shortage of local tissues at the surgeon's disposal.

Gracilis muscle flap with a tissue-engineered lining for experimental bladder wall reconstruction

OBJECTIVE

To assess a pedicled gracilis muscle flap pre-laminated with autologous, in vitro-expanded urothelial cells to reconstruct an entire supratrigonal bladder-wall defect in rats.

MATERIALS AND METHODS

A gracilis muscle flap was harvested from 36 male Wistar rats, transposed into the abdomen and wrapped around a silicon-block space holder. Urothelial cells were harvested and expanded ex vivo. Cells were then suspended in fibrin glue and seeded into the gracilis muscle pocket. One week later this pre-laminated flap was transposed into a surgically created supratrigonal bladder-wall defect. All animals underwent such a pre-laminated gracilis flap bladder reconstruction and were categorized into three experimental groups. All surviving animals with urothelial-culture pre-laminated gracilis flap bladder reconstruction were killed 12 weeks (group 1) later. Control rats had gracilis flaps with no cell seeding and treated only with fibrin glue (group 2) or a standard culture medium (group 3) before reconstruction.

RESULTS

Specimens stained with haematoxylin and eosin, and a specific immunohistochemical staining (AE1 and AE3-anti-cytokeratin monoclonal antibody stain) showed a continuous, multilayered functioning urothelial lining along the transposed pre-laminated gracilis flap in group 1. All animals in group 1 with an intact urothelial lining on the gracilis muscle survived, in contrast to most animals in groups 2 and 3, where eight and all 12 animals died, respectively. The surviving four animals in group 2 had no detectable urothelial lining. CONCLUSION Successful urinary reconstruction requires a contractile neo-reservoir resistant to resorption over time and a stable, protective urothelial lining. A gracilis muscle flap can be seeded with autologous cultured urothelial cells suspended in fibrin glue. This pre-laminated flap can be safely transposed on its pedicle and be successfully integrated into the remaining bladder wall, with a urothelial lining and the potential to contract. Further studies in larger animals, with a urodynamic assessment, are warranted to determine if this type of bladder-wall replacement technique is suitable for urinary reconstruction in humans.

Fluid and electrolyte abnormalities

Patients with cancer are at risk for developing a variety of fluid and electrolyte disturbances caused by the disease process or by complications from therapy. An understanding of the pathophysiology of these potential abnormalities allows the clinician to manage patients expectantly and to avoid severe metabolic disarray by correcting imbalances promptly.

Kidney transplantation in children with urinary diversion or bladder augmentation

PURPOSE

Urinary tract anomalies or dysfunction leaves the bladder unsuitable for urine drainage in a significant proportion of children presenting for kidney transplantation. We reviewed a multi-institutional experience to determine the ramifications of kidney transplantation in children with bladder augmentation or urinary diversion.

MATERIALS AND METHODS

During a 28-year period 18 boys and 12 girls 1.7 to 18 years old (mean age 12.1) received 31 kidney transplants. Cause of end stage renal disease was renal dysplasia in 8 cases, posterior urethral valves in 5, obstructive uropathy in 5, neurogenic bladder/chronic pyelonephritis in 4, spina bifida/chronic pyelonephritis in 3, prune belly syndrome in 3 and reflux in 2.

RESULTS

Of the patients 17 had augmented bladder (ileum 9, ureter 5, sigmoid 2 and stomach 1), 12 had incontinent urinary conduits (8 ileum, 6 colon) and 1 had a continent urinary reservoir. Surgical complications included 1 case each of stomal stenosis, stomal prolapse, renal artery stenosis, urine leak, enterovesical fistula and wound dehiscence. Medical complications included urinary tract infection in 21 cases and metabolic acidosis in 5. A bladder stone developed in 1 patient. There was no correlation between the incidence of symptomatic urinary tract infections and type of urinary drainage. Acidosis was more common in patients with augmented bladder (4 of 17 versus 1 of 14) but there was no correlation between the bowel segment used and the occurrence of acidosis. Graft survival was 90% at 1 year, 78% at 5 years and 60% at 10 years. Etiology of graft loss included chronic rejection in 6 cases, noncompliance in 4 and acute rejection in 1. There were no deaths.

CONCLUSIONS

Drainage of transplanted kidneys into an augmented bladder or urinary conduit is an appropriate management strategy when the native bladder is unsuitable or absent. Patients with kidney transplants drained into augmented bladder or urinary conduit are at increased risk for urine infection. Graft survival is not adversely affected compared to historical controls when a kidney transplant is drained into a urinary conduit or augmented bladder.

Kidney transplantation in children with urinary diversion or bladder augmentation

PURPOSE

Urinary tract anomalies or dysfunction leaves the bladder unsuitable for urine drainage in a significant proportion of children presenting for kidney transplantation. We reviewed a multi-institutional experience to determine the ramifications of kidney transplantation in children with bladder augmentation or urinary diversion.

MATERIALS AND METHODS

During a 28-year period 18 boys and 12 girls 1.7 to 18 years old (mean age 12.1) received 31 kidney transplants. Cause of end stage renal disease was renal dysplasia in 8 cases, posterior urethral valves in 5, obstructive uropathy in 5, neurogenic bladder/chronic pyelonephritis in 4, spina bifida/chronic pyelonephritis in 3, prune belly syndrome in 3 and reflux in 2.

RESULTS

Of the patients 17 had augmented bladder (ileum 9, ureter 5, sigmoid 2 and stomach 1), 12 had incontinent urinary conduits (8 ileum, 6 colon) and 1 had a continent urinary reservoir. Surgical complications included 1 case each of stomal stenosis, stomal prolapse, renal artery stenosis, urine leak, enterovesical fistula and wound dehiscence. Medical complications included urinary tract infection in 21 cases and metabolic acidosis in 5. A bladder stone developed in 1 patient. There was no correlation between the incidence of symptomatic urinary tract infections and type of urinary drainage. Acidosis was more common in patients with augmented bladder (4 of 17 versus 1 of 14) but there was no correlation between the bowel segment used and the occurrence of acidosis. Graft survival was 90% at 1 year, 78% at 5 years and 60% at 10 years. Etiology of graft loss included chronic rejection in 6 cases, noncompliance in 4 and acute rejection in 1. There were no deaths.

CONCLUSIONS

Drainage of transplanted kidneys into an augmented bladder or urinary conduit is an appropriate management strategy when the native bladder is unsuitable or absent. Patients with kidney transplants drained into augmented bladder or urinary conduit are at increased risk for urine infection. Graft survival is not adversely affected compared to historical controls when a kidney transplant is drained into a urinary conduit or augmented bladder.

Muscle prelamination with urothelial cell cultures via fibrin glue in rats

The purpose of the study was to transplant autologous cultured urothelial cells onto a muscle via fibrin glue as a delivery vehicle to create a vascularized, living matrix lined with urothelium that could subsequently be used for urinary reconstruction. Bladder tissue specimens from male Wistar rats (n = 32; 350--500 g) were harvested for urothelial tissue culture. After 8--10 days when the primary cultures became confluent, the cultured urothelial cells were injected underneath the rectus sheath onto the rectus muscle. As delivery vehicle we compared standard culture media and fibrin glue. At 1- and 4-week intervals following urothelial cell grafting, sections of the muscle were analyzed for urothelial graft take using Hematoxylin & Eosin and immunohistochemical staining. The histology demonstrated viable, multilayered clusters of urothelium cells on the muscle surface only in the group using the fibrin glue delivery vehicle. We conclude that a muscle can be successfully prelaminated with autologously cultured urothelial cells via fibrin glue and has therefore potential for urinary reconstructions.

Continent urinary diversion in preparation for renal transplantation: a staged approach

BACKGROUND

We prospectively assessed the safety of kidney transplantation into continent urinary intestinal reservoirs as a planned two-stage procedure in patients with absent or dysfunctional lower urinary tract.

METHODS

Between November 1990 and June 1999, 12 patients have undergone renal transplantation into continent urinary reservoirs, and a further patient with a diversion is awaiting transplantation. This was part of a larger series of 356 patients who had undergone continent diversions during that period. A further 174 patients (33%) had diversions into ileal conduits.

FINDINGS

Within a mean follow-up of 26.1 months (5-72) after transplantation renal function was stable with serum creatinine values ranging from 0.9 to 1.8 mg/dl. There were 5 reoperations in the 12 patients (40%). Two patients needed their continence mechanism replaced. One had renal vein thrombosis with loss of the transplant. The cause for this was unknown but it had been speculated that it could have been caused by graft/body size disproportion. A second kidney was successfully transplanted after 12 months. Two further revisions were required for ureteric kinking and lymphocele. The patient with orthotopic substitution voids to completion. The other patients are continent day and night with easy catheterization.

INTERPRETATION

This is one of the largest single series reported to date of renal transplantation into continent urinary diversions, and we commend the approach in carefully selected patients, but the difficulties must not be underestimated and the specific problems of intestinal urinary reservoirs have to be reckoned with. These procedures should be confined to centers with considerable experience with this type of surgery and its complications. Lifelong close surveillance is critical for the success of this concept.

Outcome of gastrocystoplasty in tertiary pediatric urology practice

PURPOSE

Although the use of stomach for bladder reconstruction has become popular during the last decade, it is not a panacea. We review our experience with gastrocystoplasty.

MATERIALS AND METHODS

We completed a retrospective chart review of 11 females and 12 males, 1.5 to 22.5 years old (mean age 10) who underwent gastrocystoplasty at Hôpital Sainte-Justine, Montreal, Quebec and Children's Hospital, Winnipeg, Manitoba, Canada between December 1990 and 1998. Primary diagnoses included spinal dysraphism in 14 patients, posterior urethral valves in 3, cloacal exstrophy in 2, cloacal outlet anomaly in 2, multiple failed ureteral reimplantations with bladder dysfunction in 1 and neurogenic bladder of uncertain etiology in 1. Three patients presented with chronic renal failure. Concurrent reconstructive surgery included ureteral reimplantation in 10 patients, bladder neck plasty in 4 or closure in 4, and continent urinary diversion in 5.

RESULTS

Acute postoperative complications included urosepsis in 2 cases, bowel obstruction in 2 and ureteral obstruction in 1. Followup ranged from 4 to 86 months (mean 45). Long-term complications consisted of intractable hematuria-dysuria syndrome in 5 cases, inability to catheterize in 3, perineal urinary fistula in 2, new onset hydronephrosis in 2, continent stomal stenosis in 1 and bladder calculus in 1. Proton pump inhibitors and/or histamine 2 antagonists were used in 16 of the 23 patients to prevent the hematuria-dysuria syndrome. In 5 cases the hematuria-dysuria syndrome was poorly controlled medically and 3 were converted to another form of urinary reconstruction. In 18 of 20 cases voiding cystourethrography revealed no vesicoureteral reflux, and in 18 of 21 ultrasound documented stable or improved upper tracts. Socially acceptable urinary continence was attained in 19 of the 21 patients.

CONCLUSIONS

The use of stomach for bladder augmentation may be considered in patients with cloacal exstrophy and/or metabolic acidosis. Histamine blockers and/or proton pump inhibitors may be required to prevent the hematuria-dysuria syndrome. Symptoms of the hematuria-dysuria syndrome may be disabling and may mandate alternative forms of urinary tract reconstruction.

Decreased linear growth associated with intestinal bladder augmentation in children with bladder exstrophy

PURPOSE

We determine if enterocystoplasty results in delayed linear growth using a case controlled study to observe the effects of intestinal bladder augmentation on growth in patients with bladder exstrophy.

MATERIALS AND METHODS

A total of 50 patients who had undergone bladder augmentation for incontinence due to classic bladder exstrophy were selected from our patient database and matched for gender, age and type of exstrophy with 50 patients who had nonaugmented bladder exstrophy. Patients were then contacted and asked to permit the pediatricians to release growth charts. Once consent was obtained the charts were requested from the pediatricians, and evaluable data, defined as at least 1 height before and after augmentation, were obtained for 17 of 50 (34%) augmented and 15 of 50 (30%) nonaugmented cases.

RESULTS

Mean age at surgery was 7.7 years. Delayed growth as defined by a postoperative decrease in percentile height occurred in 14 of 17 (82%) augmented cases (mean loss 15.6 percentile points). Delayed growth after age 7.7 years occurred in 5 of 15 (33%) controls but average growth for the entire group was 6.7 percentile points (p = 0. 014). Mean followup was 5.7 years (median 4.9) for the augmented group and 7.3 years (median 8.2) for the control group.

CONCLUSIONS

Intestinal bladder augmentation is associated with a nearly universal decrease in percentile height. Close long-term followup of these patients and analysis of subtle metabolic alterations may provide information to help minimize or prevent growth impediment in the future.

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.

Urolithiasis following formation of a continent urostomy: case report and review of the literature

BACKGROUND

Formation of urinary stones in a continent urostomy (Indiana pouch) has been described as a late complication. Management of a patient with symptomatic multiple large stones and review of the literature are outlined.

CASE REPORT

A 32-year-old woman presented with recurrent urinary tract infections and pyelonephritis 6 years after a total pelvic exenteration and creation of a continent urostomy for central recurrent carcinoma of the cervix after radical pelvic radiation. Multiple large stones were found to be the underlying etiology. Laparotomy, enterocystotomy, and removal of stones were performed without apparent complication.

CONCLUSION

It is recommended that for single calculi or multiple small stones, electroshock wave lithotripsy or the percutaneous endoscopic approach be considered. For larger stones the use of laparotomy and enterocystostomy may be appropriate.

New methods of bladder augmentation

Gastrointestinal segments are commonly used for bladder replacement or repair. However, when gastrointestinal tissue is in contact with the urinary tract, several complications may ensue. Recent surgical approaches have relied on native urological tissue for reconstruction. These are based on sound surgical principles, allowing for the exclusion of tissue that is not urological. De-epithelialized bowel segments, either alone or over native urothelium, have also been used. An experimental system of progressive dilatation for ureters and bladders has been proposed. This appears promising, although it has yet to be attempted clinically. There has been a resurgence of interest in the use of acellular collagen-based matrices as scaffolds for bladder regeneration; experimental work is currently underway. Recently, functional bladder tissue has been engineered using selective cell transplantation. This technique uses autologous cells, so avoiding rejection. Tissue is obtained from the host, the cells then dissociated and expanded in vitro, re-attached to a matrix and implanted into the same host. Clinical trials are currently being arranged. Even though the use of bowel for bladder tissue replacement was first proposed over 100 years ago, it remains the gold standard, despite its associated problems. It is evident that urothelial-urothelial anastomoses are preferable functionally. Experience is currently being gained with the recent clinical and experimental approaches to augmentation cystoplasty. It is hoped that this will result in more technologies and methods for bladder augmentation.

Urothelium-preserving augmentation cystoplasty covered with a peritoneal flap

OBJECTIVES

To present the results of bladder autoaugmentation covered with a peritoneal flap in patients with bladder dysfunction.

PATIENTS AND METHODS

Thirteen patients (seven male and six female, mean age 11.9 years, range 4-25) who underwent autoaugmentation covered with a peritoneal flap were evaluated. Seven had different forms of myelodysplasia, four had spinal cord injury and two had Hinman syndrome as the cause of bladder dysfunction. Indications for augmentation included upper tract deterioration, urinary incontinence and recurrent urinary tract infection, despite anticholin-ergic therapy.

RESULTS

The mean bladder capacity increased by 18.6% after surgery and the mean compliance at capacity increased from 3.4 to 5.8 cmH2O/mL. All patients were incontinent before surgery and continence was achieved in only six afterward. Four patients showed no clinical or urodynamic improvement and required re-augmentation using intestinal segments. Only three patients needed no anticholinergic therapy after surgery. All four patients in whom the procedure failed had capacities of < 30% of that expected for their age. There were no metabolic problems.

CONCLUSION

Autoaugmentation combined with a peritoneal flap is an easy procedure but the clinical results are poor in some patients, especially those with a small initial bladder capacity. The need for secondary augmentation with enteric segments was common. The use of a peritoneal flap does not appear to increase the capacity and compliance more than is obtained with the classical technique; it may prevent adhesion to the abdominal wall and make a secondary procedure easier. As the increase in capacity and compliance is limited with this technique, a urothelium-preserving augmentation should be reserved for those bladders with a relatively good initial capacity.