Estimation of glomerular filtration rate and bladder capacity: the effect of maturation, ageing, gender and size

OBJECTIVE

To show that glomerular filtration rate (GFR) and bladder capacity (BC) develop isometrically, and to provide graphs for estimating GFR and BC for specific individuals of any age, sex, height and weight, for cystometric purposes.

MATERIALS AND METHODS

GFR and BC data were collected from published reports; graphs relating GFR and BC to age, sex, height and weight were obtained by using a computerized curve-fitting technique that minimizes the 1.1 power of the absolute error.

RESULTS

The plots show the GFR and BC for individuals of 10th, 50th and 90th percentile height and weight as a function of age and sex for different physiological conditions. GFR increases up to age 20 years and thereafter declines, whereas GFR per unit body surface area reaches a maximum at 3.25 years old and declines thereafter.

CONCLUSIONS

The clinical management strategy to preserve or enhance renal function in paediatric and adult nephrological disease should incorporate the present data on development, growth, ageing and deterioration of function. These data should be used when interpreting cystometrograms and evaluating compliance. The graphs are useful for clinically estimating GFR and BC, especially when estimating infusion rate and BC for individual patients. BC and GFR develop isometrically with a proportionality constant of 4.56 min, except from birth to 1.5 years of age. Accordingly, individuals with healthy urinary systems, irrespective of age, sex and size, in the same physiological conditions have, on average, the same time to reach BC, ranging from 7 h at a normal 1% GFR to 41 min at the maximum diuresis of 10% GFR.

Dysfunction of the lower urinary and distal gastrointestinal tracts in pediatric patients with known spinal cord problems

Destruction of the urinary tract in children with elimination, storage, and holding dysfunction of the lower urinary and the distal GI tracts is caused primarily by high intravesical pressure. UTI accelerates this process. The LPP and the status of the urethral control mechanism and its relationship to the detrusor are the primary determinants of intravesical pressure. Intravesical pressures of more than 40 cm H2O are dangerous because they cause a pressure gradient that is transmitted proximally to the renal papillae, which results in the cessation of renal blood flow and a loss of renal function over time. Hydroureteronephrosis, VUR, UTI, urinary incontinence, and calculi formation also may occur. If these dangerously high intravesical pressures remain untreated, renal failure is likely to occur over time. These children then require dialysis or renal transplantation to survive, which is tragic and represents an enormous economic cost to society. Renal failure and upper urinary tract damage is nearly 100% preventable with early and appropriate evaluation and treatment. CIC is a crucial part of the management of these children and has been shown to be safe and effective, even in newborn boys. The use of the Credé maneuver (i.e., manual compression) to empty the bladder is obsolete and should be abandoned. The distal GI tract is inseparable from the lower urinary tract and must be treated simultaneously. Failure to treat the distal GI tract yields poor clinical results and much patient dissatisfaction and makes it difficult or impossible to treat the child's urinary tract problem successfully. Bowel-management programs must include daily high water and fiber intake, together with digital perianal stimulation or fecal extraction. Neuropathic bladder and bowel problems that are intractable to conservative medical and mechanical (i.e., CIC and digital perianal stimulation or fecal extraction, respectively) management almost always can be corrected surgically with high success rates in cooperative patients. Finally, neuropathic bladder and bowel problems can be extremely isolating and debilitating problems. Psychologic counseling and emotional support must be provided as needed. The care that these patients receive must be organized, comprehensive, and correlated with these patients' lifestyles. If these children are evaluated and treated early, they have the potential to live long, healthy, and productive lives.

Pediatric urine testing

Today, urinalysis is one of the most common clinical tests ordered for adult and pediatric patients. Because urine specimens are usually readily available and are obtained noninvasively, the urine testing is well suited for children. This article discusses the most common urine tests performed in children for screening purposes and also less common tests for diagnosis of specific disorders. Special considerations regarding urine specimen collection in children are discussed. Some simple tests that are underused by clinicians are mentioned, as are some exciting new molecular applications of urine testing.

Dysfunctional elimination syndrome in children without obvious spinal cord diseases

Elimination dysfunction is a functional disease that encompasses the urinary and GI tracts. Because the presentation is varied and ED is a disease of exclusion, a thorough history and physical examination are mandatory. Noninvasive management that includes the "fundamental four" and continuous engagement and encouragement of the patient and family are the pillars of treatment. For patients who are refractory to this approach, new research in children-directed biofeedback research shows promise.

Enuresis

The authors do not have all of the data about enuresis, and many children are subject to relapses or failure of treatment. There is no cause for despondency, however. Enuresis is no longer a mystery. Good data exist about the natural history, epidemiology, and etiology of enuresis. In addition, multiple treatment modalities are available to practitioners. This article has sought to review the scientific literature and to relate the authors' experience with enuresis. The authors recommend a treatment program for children with monosymptomatic nocturnal enuresis that includes removal of caffeine from the diet. Enuretic children do not consume enough fluid, and the authors recommend that the daily fluid requirement be divided during the day: 40% in the morning, 40% in the afternoon, and 20% in the evening, with no restriction of fluid. Normalization of small functional bladder capacities may help to cure enuresis and has an effect on the efficacy of other therapies. Treatment of enuretics with antibiotics is effective in children with UTI, bacteriuria, or cystitis cystica. DDAVP has been shown to be effective in the treatment of enuresis, especially in children who have achieved a normal functional bladder capacity. Bladder alarm systems also offer a potential cure of enuresis, are inexpensive, and show a low relapse rate.

Prototype system for enhancing cystometric analysis with special emphasis on the pediatric population

BACKGROUND AND PURPOSE

A urodynamic test system of improved accuracy and reliability was developed and implemented for enhancing cystometry. This system integrates known medical information, including the specialized problems of pediatric urodynamics, with the cystometric and imaging data.

METHODS

After the requirements for the ideal cystometrogram test unit were established, a system was constructed, calibrated, and implemented in clinical practice. The patient's age, size, and sex are used to produce a patient-specific pressure-volume template for the cystometrogram test.

RESULTS

This template showed the minimal and normal bladder capacities and the physiologically safe, equivocal, and dangerous pressure fields coded with symbolic colors. Different time averages of the pressure data were used to show bladder factors such as compliance and instability. The templates with data were presented automatically (therefore objectively) without operator intervention on monitors during testing and as printed copies on completion.

CONCLUSIONS

The presentation of data in an easily understood format facilitates effective communication between the urologist, referring physician, and patient. Some of the physiological and statistical problems in pediatric urodynamic testing are efficiently and accurately resolved by this system, resulting in better analysis and diagnostic capabilities.

Knowledge-based segmentation of pediatric kidneys in CT for measurement of parenchymal volume

PURPOSE

The purpose of this work was to develop an automated method for segmenting pediatric kidneys in helical CT images and measuring their volume.

METHOD

An automated system was developed to segment the kidneys. Parametric features of anatomic structures were used to guide segmentation and labeling of image regions. Kidney volumes were calculated by summing included voxels. For validation, the kidney volumes of four swine were calculated using our approach and compared with the "true" volumes measured after harvesting the kidneys. Automated volume calculations were also performed in a cohort of nine children.

RESULTS

The mean difference between the calculated and measured values in the swine kidneys was 1.38 ml. For the pediatric cases, calculated volumes ranged from 41.7 to 252.1 ml/kidney, and the mean ratio of right to left kidney volume was 0.96.

CONCLUSION

These results demonstrate the accuracy of a volumetric technique that may in the future provide an objective assessment of renal damage.

Urinary continence after staged bladder reconstruction for cloacal exstrophy: the effect of coexisting neurological abnormalities on urinary continence

PURPOSE

We determined whether there is a difference in the incidence of urinary continence in cloacal and classic bladder exstrophy after staged bladder neck reconstruction using the Young-Dees-Leadbetter technique.

MATERIALS AND METHODS

We reviewed the records of patients with cloacal and classic bladder exstrophy who underwent staged bladder neck reconstruction from 1971 to 1997.

RESULTS

The Young-Dees-Leadbetter bladder neck reconstruction was completed in 23 patients with cloacal exstrophy, of whom 5 (22%) became continent and 18 (78%) have persistent incontinence. A clinically apparent neurological abnormality significantly hindered the achievement of continence. Specifically 1 of the 13 children (7%) with versus 4 of the 10 (40%) without a neurological abnormality became continent (p <0.05). In contrast, staged reconstruction of classic bladder exstrophy resulted in urinary continence in 67 of the 82 patients (82%). Of the 67 continent patients 23 (34%) cannot void and require intermittent catheterization. None of the patients with classic exstrophy had a neurological deficit.

CONCLUSIONS

The ability of the Young-Dees-Leadbetter bladder neck reconstruction to result in urinary continence significantly differs in the cloacal and classic bladder exstrophy populations (22 versus 82%, p <0.001). Our findings also suggest that a coexisting neurological abnormality significantly hinders the ability to reconstruct a functional bladder in patients with cloacal exstrophy.

Urethral replacement with vascularized tunica vaginalis: defining the optimal form of use

PURPOSE

Residual urethral defects after failed hypospadias surgery present difficulties in reconstruction. In these situations, repair using vascularized tissue flaps remains ideal, yet challenging. In order to offer more surgical alternatives in these cases, the use of vascularized tunica vaginalis flaps as urethral replacements has recently been established in an animal model. We undertook the following studies to further define the role of tunica vaginalis in urethral reconstruction.

MATERIALS AND METHODS

A vascularized flap of tunica vaginalis was used to replace an experimentally created 25-30 mm. gap in the anterior urethra of 26 rabbits, either as an onlay or tube flap. A control group consisting of 7 animals underwent only a segmental anterior urethral resection and primary re-anastomosis.

RESULTS

Satisfactory urethral healing occurred in all control animals that survived the procedure. All 8 animals which had tunica vaginalis tube flap reconstruction underwent contracture of the neourethra probably secondary to the presence of striated cremasteric muscle elements brought with the tunica during mobilization. All 16 animals available for long term study in the onlay flap group had excellent flap viability and 100% urethral patency rates. The mesothelial lining of the tunica was seen to be replaced by a stratified epithelial lining similar to the urothelial lining of the native urethra.

CONCLUSION

The tunica vaginalis is a viable alternative to other tissues presently used for urethral replacement and can be used successfully as a vascularized onlay flap.

Ureteral opening pressure: a novel parameter for the evaluation of pediatric hydronephrosis

PURPOSE

The antegrade nephrostogram is an important tool in the evaluation of the upper urinary tract. However, the information currently provided by a nephrostogram is largely limited to anatomical details. To establish a meaningful pressure-flow parameter that may be incorporated into a routine nephrostogram, we evaluated the ureteral opening pressure (defined as the pressure at which contrast material is first seen beyond the suspected site of obstruction) and correlated these findings with the results of pressure-flow studies performed with an external infusion and/or furosemide induced diuresis.

MATERIALS AND METHODS

A total of 52 renal units were studied under a prospective pressure-flow study protocol. All patients had grade 3 or 4 hydronephrosis (Society of Fetal Urology classification) and patient age range was 0.2 to 12 years (median 1.1). The suspected sites of obstruction were the ureteropelvic and ureterovesical junctions in 42 and 10 renal units, respectively. With the patient under general anesthesia 22 gauge percutaneous nephrostomy needles were inserted. Pressure-flow studies with an external infusion and/or furosemide induced diuresis were then performed. As the renal pelvic pressure progressively increased during the course of the pressure-flow studies, the renal pelvic pressure at which contrast material was first seen to appear distal to the suspected site of obstruction was recorded as the ureteral opening pressure. Ureteral opening pressures were compared to the results of the pressure-flow studies.

RESULTS

With a positive test defined as renal pelvic pressure greater than 14 cm. water, positive ureteral opening pressures were associated with positive pressure-flow study results in 100% of the cases, regardless of which form of pressure-flow study was used or where the suspected site of obstruction was located. In contrast, negative ureteral opening pressures had specificities and negative predictive values of only 19 to 57%, depending on the form of the pressure-flow study and the suspected site of obstruction.

CONCLUSIONS

An elevated ureteral opening pressure was 100% predictive of obstruction and may obviate the need for more elaborate pressure-flow analyses. However, if the ureteral pelvic pressure remained low, the possibility of a potentially significant obstruction could not be definitively eliminated and further evaluation was required.

Bilateral single ureteral ectopia: difficulty attaining continence using standard bladder neck repair

PURPOSE

We reviewed the surgical results of the management of bilateral single ureteral ectopia, a rare congenital cause of severe urinary incontinence.

MATERIALS AND METHODS

We reviewed the records of 6 girls and 1 male infant who presented to 1 institution with this diagnosis in a 10-year period.

RESULTS

All patients were incontinent and 3 had undergone ureteral reimplantation as an initial procedure with persistent postoperative wetting. Of the 5 patients who underwent a total of 8 attempts at increasing bladder outlet resistance, including 3 Young-Dees-Leadbetter, 2 Kropp, 1 Stamey, 1 Burch and 1 pubovaginal sling procedure, 2 also underwent simultaneous bladder augmentation to increase bladder capacity. However, none of these children had satisfactory continence after the continence procedure. Three of these patients who subsequently underwent appendicovesicostomy with bladder neck closure are continent. The 2 remaining patients underwent initial appendicovesicostomy with bladder neck closure and augmentation, and they are also continent.

CONCLUSIONS

In our series total day and nighttime continence was only achieved by bladder neck closure, appendicovesicostomy and augmentation. Attempts at increasing bladder outlet resistance in patients with bilateral single ectopic ureters led to suboptimal rates of success even when adequate bladder capacity had been ensured by simultaneous augmentation.

Intestinal metaplasia is not a strong risk factor for bladder cancer: study of 53 cases with long-term follow-up

OBJECTIVES

Intestinal metaplasia often coexists with adenocarcinoma of the urinary bladder, suggesting to some investigators that it is premalignant. However, the natural history and long-term outcome of intestinal metaplasia in isolation are unknown. We report 53 cases of intestinal metaplasia of the urinary bladder followed for more than 10 years.

METHODS

We reviewed the Mayo Clinic surgical pathology files between 1926 and 1996 and all patients with exstrophic bladder recorded in the files of the Hospital for Sick Children (Toronto, Ontario, Canada) and Dallas Children's Hospital (Dallas, Texas) between 1953 and 1987, and identified all patients with intestinal metaplasia of the bladder.

RESULTS

A total of 53 cases were identified from both series, and none of the patients developed adenocarcinoma of the bladder. The Mayo Clinic series consisted of 24 patients. Nineteen of the 24 (79.1%) were alive without evidence of cancer (median follow-up 14 years, range 0.9 to 53), and 5 patients died of intercurrent disease (at 0.9, 4, 8, 11, and 53 years after diagnosis) without evidence of bladder cancer. The Dallas Children's Hospital and the Hospital for Sick Children series consisted of 29 patients. Twenty-seven of the 29 (93.1%) were alive without evidence of cancer (median follow-up 13 years, range 3 to 23.9). Two patients died of trauma (at 10.9 and 12 years after diagnosis) and at autopsy had no evidence of bladder cancer.

CONCLUSIONS

Intestinal metaplasia of the urinary bladder is not a strong risk factor for adenocarcinoma or urothelial cancer.

Renal transplantation in children following augmentation ureterocystoplasty

OBJECTIVES

To assess the impact of augmentation ureterocystoplasty on the success of cadaveric renal transplantation in children with dysfunctional bladders.

METHODS

Two patients with end-stage renal failure secondary to dysfunctional bladders (one myelodysplasia and one posterior urethral valves) underwent augmentation ureterocystoplasty prior to renal transplantation in order to increase bladder capacity and improve compliance.

RESULTS

Significant improvement of bladder storage function was achieved in both patients. By the use of megaureter for augmentation, untoward sequelae of enteric or gastric augmentation were obviated. Renal transplantation was successful in both patients. Both have normal renal function 4 and 3 years after transplantation.

CONCLUSIONS

Renal transplantation into bladders previously augmented with megaureters is successful. The use of urothelial-lined biomaterial for augmentation avoids the potential complications of gastro- or enterocystoplasty, which are especially dangerous in transplant patients.

Outcome analysis of vesicoureteral reflux in children with myelodysplasia

PURPOSE

Vesicoureteral reflux in children with myelodysplasia is usually secondary to abnormal bladder storage. The purpose of this study was to assess the outcome of vesicoureteral reflux in children with myelodysplasia.

MATERIALS AND METHODS

We retrospectively analyzed the records of 319 children with myelodysplasia who presented to our institution between 1978 and 1985. Of these children 95 presented with or had reflux during followup and they were treated with prophylactic antibiotics. Clean intermittent catheterization and anticholinergic medication were added to the regimen when indicated.

RESULTS

Reflux resolved in 63% of these patients with nonsurgical management. Temporary cutaneous vesicostomy was performed in 23 children (24%) with persistent high grade reflux or evidence of upper tract deterioration. Ureteral reimplantation and augmentation cystoplasty were performed in 18 (20%) and 8 (8%) patients, respectively. No patient had progression to chronic renal failure and scars developed in only 14 kidneys (10%).

CONCLUSIONS

In the majority of cases (63%) reflux resolved with nonsurgical management. Reflux in these patients should not be treated in isolation. The management of reflux is primarily aimed at improving bladder storage. The combination of aggressive nonsurgical therapy and close observation is recommended. This regimen leads to the satisfactory resolution of reflux with minimal renal morbidity.

The dartos flap as an adjunct in preventing urethrocutaneous fistulas in repeat hypospadias surgery

PURPOSE

Vascularized flaps for repeat hypospadias repair are often limited. We report our experience with the dartos flap in children undergoing secondary hypospadias and complex urethral repair.

MATERIALS AND METHODS

The dartos flap is fibroadipose tissue between the scrotal skin and tunica vaginalis layers with its vascular pedicle based at the penoscrotal angle. The flap reaches the distal penile shaft without tension. Eight patients 1 to 17 years old (mean age 6) underwent urethral surgery and an interposed dartos flap procedure in 1994 to 1995.

RESULTS

Of 6 patients cosmesis was excellent in 84%, erections were straight in 100%, and urinary streams were of good quality and without fistula in 100% after repeat hypospadias surgery. Following staged repair for anterior urethral valves a urethrocutaneous fistula developed in 1 patient and following urethral duplication repair results were excellent in 1. Mean followup was 1 year.

CONCLUSIONS

The dartos flap is easy to mobilize and it provides excellent coverage for repeat proximal hypospadias surgery, since the dartos remains undisturbed. We endorse its use for complex urethral surgery and believe that the extra layer of closure helps to prevent urethrocutaneous fistulas.

Outcome analysis of Mitrofanoff principle applications using appendix and ureter to umbilical and lower quadrant stomal sites

PURPOSE

We compared the indications for and results of application of the Mitrofanoff principle using appendix and ureter to umbilical and lower quadrant stomal sites.

MATERIAL AND METHODS

We created continent catheterizable conduits in 60 patients 3 days to 20 years old (mean age 8.8 years). The primary indication was refractory urinary incontinence associated with bladder or cloacal exstrophy, or anomalies in 31 cases. We constructed 38 umbilical (all appendix) and 22 lower quadrant (10 appendix and 12 ureter) stomas. Mean followup was 3 years.

RESULTS

We preferred the umbilicus as a stomal site for its cosmetic value. The most common indication for a lower quadrant stomal site was preservation of the retroperitoneal course of the ureter. The stomal stenosis rate was 13 and 4% in patients with umbilical and lower quadrant stomas, respectively. We preferred the appendix as a conduit due to availability. Indications for the ureter as a catheterizable conduit were absence of an adequate appendix or presence of a healthy ureter after nephrectomy. The appendiceal and ureteral conduits were catheterizable in 94 and 84% of patients, respectively, and continence was achieved in 97%.

CONCLUSIONS

In a complex group of patients with incontinence application of the Mitrofanoff principle yielded good results for either combination of stomal site or catheterizable conduit. Appendicovesicostomy to the umbilicus remains our preferred procedure.

Percutaneous vacuum vesicolithotomy under direct vision: a new technique

PURPOSE

The number of vesical calculi is increasing as the number of patients with intestinocystoplasty increases. We describe our technique for easily removing vesical calculi in children via an atraumatic percutaneous endoscopic approach.

MATERIALS AND METHODS

The procedure involves percutaneous suprapubic puncture and direct visualization of the calculi via cystoscopy through the urethra or via a second suprapubic puncture when the bladder neck is closed. The stones are vacuumed up 1 at a time with suction tubing through the suprapubic working sheath in a controlled manner with no urethral trauma. Ten patients 3 to 16 years old (mean age 8) with vesicolithiasis underwent percutaneous vacuum vesicolithotomy under direct vision in 1993 to 1995.

RESULTS

Two to 12 bladder calculi were extracted (mean 7). All calculi less than 1 cm. were removed by this procedure. All bladder calculi between 1 and 1.5 cm. were also removed but they required simultaneous electrohydraulic lithotripsy. There were no complications at a mean 1-year followup. Mean hospitalization was less than 24 hours (range 0 to 3 days).

CONCLUSIONS

Percutaneous vacuum vesicolithotomy is highly successful, easy to perform and safe for extracting vesical calculi. Since the procedure is done through a percutaneous sheath, it is particularly suited to the individual with an absent, small caliber, sensitive or surgically reconstructed urethra.

Minimizing stomal stenosis in appendicovesicostomy using the modified umbilical stoma

PURPOSE

We describe creation of a modified umbilical stoma as part of continent urinary diversion using appendicovesicostomy.

MATERIALS AND METHODS

Umbilical stomas were created using the eversion-inversion principle in 25 patients undergoing appendicovesicostomy.

RESULTS

Mean followup was 3 years. Cosmesis of the umbilical stoma was good in all cases. Stomal stenosis required surgical revision in 8% of cases.

CONCLUSIONS

We recommend our modified umbilical stomal technique for appendicovesicostomy because it allows good cosmesis without compromising stomal function.

Pressure decay half-life: a method for characterizing upper urinary tract urine transport

PURPOSE

We examined the pressure dynamics of hydronephrotic kidneys after elevated renal pelvic pressure developed.

MATERIALS AND METHODS

A total of 40 patients (44 renal units) 0.2 to 12 years old was evaluated. Transiently elevated renal pelvic pressure was induced with a percutaneous nephrostomy infusion. After renal pelvic pressure increased the infusion was stopped and the subsequent decrease in pressure with time was plotted as a pressure decay curve. The rapidity of the decrease in renal pelvic pressure was then quantitated as a half-life for each pressure decay curve. Pressure decay half-lives were compared to corresponding pressure flow study results and diuretic nuclear renography half-lives.

RESULTS

Renal units without elevated renal pelvic pressure during infusion at a high physiological flow rate were associated with relatively rapid pressure decay, whereas those with elevated renal pelvic pressure during infusion were associated with much slower pressure decay (p < 0.0001). Diuretic nuclear renography half-lives had no correlation with collecting system pressure dynamics.

CONCLUSIONS

Pressure decay half-life provides an objective quantitative measure of the relative tendency for elevated renal pelvic pressure to persist. When used in conjunction with other diagnostic modalities, it may be a useful parameter for a comprehensive assessment of the risk of pressure induced injury in hydronephrotic kidneys.

Pediatric renal transplantation into the abnormal urinary tract

Many children with end-stage renal disease have significant urinary tract problems other than irreversible loss of native kidney function. These significant other urinary tract problems, if not corrected prior to transplantation, may significantly increase recipient mortality, graft loss, and patient morbidity. These other urinary tract problems may cause hydroureteronephrosis in the transplanted kidney, lead to an increased incidence of graft rejection, be the source of sepsis after subsequent immunosuppression, and cause hypertension. In addition, pre-existing urinary diversion, large interabdominal masses, or previous cancer require specific pre-transplant management plans. Potential pediatric transplant recipients with other significant urinary tract problems can be classified according to three parameters; anatomical extent, pathology, and pathophysiology of the significant other problems. Particular attention must be paid to pre-existing lower tract problems. Strategy must be worked out pre transplant as to how the lower urinary tract is going to store, hold, and empty urine. The means for assessing the potential recipients and strategies and techniques for correcting pre-existing problems have been summarized in this article.

Donor aortic cuff reduces the rate of anastomotic arterial stenosis in pediatric renal transplantation

A total of 333 pediatric renal transplantations performed at our institution between January 1977 and July 1994 was retrospectively reviewed to provide guidelines for minimizing the incidence of transplant renal artery stenosis. The patients who had renal artery stenosis were 3 months to 17.5 years old (median age 9.3 years) at the time of transplantation and the condition was diagnosed 2.2 months to 2.5 years (median 4.2 months) after transplantation. Renal artery stenosis was diagnosed in 19 transplants (19 of 333, 5.7%) as a result of severe hypertension or renal function deterioration. Stenosis occurred at the anastomosis in 7 cases (37%) and distal to the anastomosis in 12 (63%). Transplantations performed with a donor aortic cuff resulted in a lower rate of renal artery stenosis at the anastomosis (0 of 193, 0%) compared to those performed without a cuff (7 of 140, 5.0%, p = 0.0021). The rate of renal artery stenosis distal to the anastomosis was not different regardless of whether a cuff was used (5 of 193 cases, 2.6%) or not (7 of 140, 5.0%, p = 0.37). End-to-end anastomoses to internal iliac arteries, which were always performed without cuffs, had a particularly high rate of renal artery stenosis (3 of 10, 30%) compared to end-to-side anastomoses performed without cuffs (4 of 130, 3.1%, p = 0.0080). Bench surgery or multiple renal arteries did not adversely influence the rate of renal artery stenosis. With prompt diagnosis and treatment the actuarial graft survival of the transplants with renal artery stenosis was similar to that of the transplants without renal artery stenosis (p > 0.05).

Evaluation of pediatric hydronephrosis using individualized pressure flow criteria

In pursuit of a diagnostic modality better able to assess collecting system urine transport characteristics while operating within physiological ranges, a new set of guidelines for the pressure flow study was proposed. An infusion rate individualized for each patient was chosen based on a calculated estimate of the maximum physiological urine output, adjusted for patient size and age. The upper limit of normal renal pelvic pressure used was 14 cm. water. We evaluated 37 renal units with grade 3 or 4 hydronephrosis with the individualized pressure flow study. Patient age ranged from 0.2 to 12 years (median 1.1). Calculated individualized infusion rates ranged from 1.3 to 12.5 ml. per minute and resulting renal pelvic pressures ranged from 7 to greater than 40 cm. water. In each patient the corresponding renal pelvic pressure resulting from a fixed 10 ml. per minute infusion rate was uniformly equal to or higher than the corresponding individualized study pressures (p < 0.0001). Disagreement between the individualized and fixed rate pressure flow studies was highest in the younger patients. The correlation coefficient between diuretic nuclear renography half-times and individualized pressure flow results was 0.09, indicative of a random association between the 2 variables. By using individualized infusion rates based on the calculated estimate of the maximum physiological urine output, much of the falsely high pressures induced by nonphysiologically high fixed infusion rates in pediatric patients can be avoided.

Contradictory supranormal nuclear renographic differential renal function: fact or artifact?

We previously reported contradictory supranormal nuclear renographic differential renal function in cases of unilateral hydroureteronephrosis, in which the kidneys with hydroureteronephrosis paradoxically had a greater differential function than the contralateral normal mate, based on diethylenetriaminepentaacetic acid (DTPA) nuclear renography. To evaluate whether DTPA supranormal differential function represented true hyperfunction, patients with DTPA supranormal differential function were evaluated with dimercaptosuccinic acid (DMSA) nuclear renography and the results were compared. A total of 16 patients with unilateral hydronephrosis was identified to have DTPA differential function of 53% or more. They were younger than age 1 year and had never undergone any urological surgery. In all 16 patients the DMSA differential function (mean 51.1%, range 42 to 57%) was lower than their own corresponding DTPA differential function (mean 58.3%, range 53 to 66%, p < 0.0001). In addition, the DMSA differential function was not significantly different from the intuitively anticipated mean of 50% (p = 0.48). The DTPA supranormal differential function identified in our patients was not corroborated by the DMSA differential function. With recent evidence that DMSA differential function may be a better predictor of outcome following relief of unilateral ureteral obstruction consideration should be given to using DMSA as a potentially more relevant method for differential function measurement in the setting of unilateral hydronephrosis. Conversely, until the potential deficiencies of DTPA are fully understood caution should be exercised in the interpretation of DTPA differential function in the setting of hydronephrosis.

The effect of temporary cutaneous diversion on ultimate bladder function

We evaluated the effect of temporary cutaneous diversion on bladder function in cases of various congenital uropathies. The clinical courses of patients who underwent reversal of vesicostomy or pyelostomy/ureterostomy in a 7-year period were reviewed. Indications for diversion included azotemia, massive hydronephrosis, high grade reflux and/or incomplete bladder emptying. Mean age at diversion was 15 weeks. Overall 75 cases were evaluated (posterior urethral valves in 31, neurogenic bladder in 16, reflux in 14, the syndrome of vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, and radial and renal anomalies in 8 and other in 6). Of 55 patients who underwent undiversion by direct closure only 2 required later augmentation for bladder/renal deterioration. Excluding the myelomeningocele patients on clean intermittent catheterization 45 of 46 who underwent direct closure were able to void spontaneously with acceptable post-void residuals. Urodynamics in 22 cases revealed normal bladder capacity at pressures below 30 cm. water in 19 (86%) after direct closure. We conclude that after a period of defunctionalization approximately 75% of children will have essentially normal bladder function. The frequency of bladder augmentation varied from 54% in patients with myelomeningocele to 14% in those with vesicoureteral reflux. This observation suggests that the need for bladder augmentation in the remaining patients is more related to the effect of the primary pathological condition on the detrusor rather than the diversion itself.

Concomitant bladder neck closure and Mitrofanoff diversion for the management of intractable urinary incontinence

In a 7-year period 28 patients 1 to 20 years old have undergone bladder neck closure in conjunction with Mitrofanoff diversion for the management of severe incontinence. Surgery was performed as a salvage procedure in 19 patients and as a primary anti-incontinence procedure in 9. At a mean followup of 29 months 27 of 28 patients (96%) were totally continent, requiring no pads. Bladder neck closure was primarily successful in 24 of 28 patients (86%) and 25 (89%) had stable upper tracts. Five patients had bladder calculi and 5 required stomal revisions. One child had a bladder perforation associated with blunt trauma. Bladder neck closure and Mitrofanoff diversion were done without bladder augmentation in 11 cases and augmentation was performed previously or concurrently in the remainder. Four patients who did not initially undergo augmentation required later augmentation (2 for hydronephrosis and 2 for persistent incontinence). We conclude that bladder neck closure in conjunction with Mitrofanoff diversion is highly efficacious in achieving continence in a highly complex subgroup of patients with intractable urinary leakage. With careful patient selection and diligent followup total continence can be achieved in this most difficult patient population.

Voiding efficiency after ureteral reimplantation: a comparison of extravesical and intravesical techniques

The purpose of our study was to examine postoperative changes and recovery in voiding efficiency after intravesical and extravesical ureteral reimplantation. Retrospective review was performed of 188 cases. Inclusion criteria were the presence of primary vesicoureteral reflux and the absence of previous lower urinary tract surgery. Voiding efficiency after ureteral reimplantation was assessed based on post-void residual volume measurements. It was found that postoperative voiding efficiency of patients in the extravesical unilateral group was similar to that in the intravesical group, while the extravesical bilateral group had a statistically significantly higher proportion of patients with transient voiding inefficiency. A statistically higher proportion of those in the extravesical bilateral group also required some form of urinary catheter drainage for a longer period. However, on more prolonged followup all evaluable patients in the 3 groups fully regained voiding efficiency.

Histologic studies of intravesical oxybutynin in the rabbit

Intravesically applied oxybutynin has been reported to have no significant systemic anticholinergic side effects, with excellent efficacy in the treatment of neurogenic bladder dysfunction. Currently, the morphologic effects of intravesical oxybutynin on the local bladder tissue are not well established. It is the purpose of this study to address this issue in an animal model. Thirty-nine New Zealand White female rabbits were catheterized daily and intravesical solutions instilled for as long as 30 days. In part A of the study, the overall histologic effects of intravesical oxybutynin were examined by comparing oxybutynin with saline administration. Part B of this study compared the relative effects of crushed oxybutynin tablets and pure oxybutynin powder. The bladder histology and urine microbiological studies were analyzed in a blinded fashion. We found that the crushed oxybutynin tablets and saline administered intravesically produced similarly mild inflammation in the bladders (p < 0.05). When we compared the crushed oxybutynin tablets and pure oxybutynin powder, however, the crushed tablet group was found to have a mild eosinophilic infiltrate seen in 5 of 9 animals, which was not observed in any of the animals in the other groups (p = 0.029). Qualitative and quantitative analyses of the microbiological findings were not different among the different groups (p > 0.05). Our findings support the clinical use of intravesical oxybutynin as being safe for local tissue. However, consideration should be given to the use of the pure powdered form of oxybutynin, since the crushed oxybutynin tablets may lead to allergic reactions.

Voiding efficiency after ureteral reimplantation: a comparison of extravesical and intravesical techniques

The purpose of our study was to examine postoperative changes and recovery in voiding efficiency after intravesical and extravesical ureteral reimplantation. Retrospective review was performed of 188 cases. Inclusion criteria were the presence of primary vesicoureteral reflux and the absence of previous lower urinary tract surgery. Voiding efficiency after ureteral reimplantation was assessed based on post-void residual volume measurements. It was found that postoperative voiding efficiency of patients in the extravesical unilateral group was similar to that in the intravesical group, while the extravesical bilateral group had a statistically significantly higher proportion of patients with transient voiding inefficiency. A statistically higher proportion of those in the extravesical bilateral group also required some form of urinary catheter drainage for a longer period. However, on more prolonged followup all evaluable patients in the 3 groups fully regained voiding efficiency.

Functional characteristics of the reconstructed neourethra after island flap urethroplasty

To test the neourethra objectively in cases judged to be clinical successes after transverse island flap hypospadias repair, we analyzed uroflowmetry data (peak flow, voided volume and ultrasonically determined post-void residuals) after repair. Patients were included if they were old enough to void volitionally and flow data were available after fistula or stricture repair. Flow data were then plotted on previously published age-dependent nomograms from normal controls. Of 80 boys available for study 51 required no secondary procedures, 16 subsequently underwent fistula repair and 13 had strictures opened. After all primary and secondary procedures 55 patients (69%) had peak flows within the normal range and 25 (31%) had peak flows below the normal range. Of the 51 boys who never had fistulas and/or strictures 37 (73%) had normal flows while 18 of 29 (62%) who underwent fistula and/or stricture repairs had normal flows (p < 0.05). Residual volume was less than 10% of voided volume in 44 of the 51 boys who clinically had no problems postoperatively, in 8 of the 13 who had strictures opened and in 15 of the 16 who underwent fistula repairs. We conclude that the neourethra is functionally equivalent to a normal urethra in most boys after transverse flap urethroplasty. A majority of boys will have normal flow even after stricture or fistula repair.

Extravesical detrusorrhaphy for refluxing ureters associated with paraureteral diverticula

OBJECTIVES

To demonstrate the effectiveness of an extravesical approach to refluxing ureters associated with paraureteral diverticula.

METHODS

Over a 39-month period, 23 children underwent repair of Hutch diverticula with refluxing ureters using an extravesical approach. Seventeen had unilateral reflux with an ipsilateral diverticulum, 4 had bilateral reflux with a unilateral diverticulum, and 2 had bilateral reflux with bilateral diverticula. Overall, 25 ureters with associated diverticula were repaired.

RESULTS

Twenty ureters were repaired with a nondismembered technique and 5 with a dismembered technique. Twenty-two of the 23 patients (96%) were successfully repaired with this approach. Three patients had transient reflux postoperatively, which resolved spontaneously within 6 months. One patient who underwent bilateral dismembered procedures for bilateral diverticula has persistent unilateral grade II reflux postoperatively. No patient developed ureteral obstruction.

CONCLUSIONS

The major advantage of this technique is seen in the minimal postoperative morbidity. The extravesical approach is a safe, simple, and effective method for the management of a refluxing ureter with an associated diverticulum.

Bilateral congenital midureteral adynamic segments

Two cases of congenital midureteral adynamic segments are presented. Both children were successfully managed with excision of the lesions and primary reanastomosis. Pathologic examination revealed probe-patent ureters with muscular disarray, suggesting functional obstruction. Appropriate management of the anomaly was dependent on precise radiographic localization of the area of narrowing, and for this retrograde urography was essential. Primary ureteroureterostomy was successful in both cases. In this report we discuss the diagnosis, embryology, radiographic evaluation, and management of this rate situation.

A modified extravesical technique for megaureter repair

OBJECTIVE

To report on the use of extravesical detrusorraphy for megaureter repair.

PATIENTS AND METHODS

Twenty-three children underwent an extravesical megaureter repair over a 25 month period. There were 17 boys and 6 girls with an average age of 4.4 years. Three children had bilateral megaureters for a total of 26 repairs. Ureters were defined as megaureters if the ureteric diameter exceeded 1.0 cm on pre-operative imaging. There were 14 obstructing and 12 refluxing ureters. Three of the refluxing ureters were tapered while five of the obstructing megaureters were tapered.

RESULTS

Twenty-one of the 23 patients were successfully repaired using this method. Complications were minimal.

CONCLUSION

The extravesical approach can be used to correct reflux or obstruction in dilated ureters with efficacy equivalent to transvesical repairs.

The sensitivity of pressure specific bladder volume versus total bladder capacity as a measure of bladder storage dysfunction

Assessment of bladder storage function requires an accurate measure of bladder capacity and pressure. Pressure specific bladder volume is the volume that a bladder can accommodate at a specific pressure. A total of 21 consecutive children with neurogenic bladders who were candidates for bladder augmentation based on standard clinical criteria (upper urinary tract deterioration, incontinence and infection) was studied to determine the efficacy of pressure specific bladder volume as a measure of bladder dysfunction. Urodynamic indexes were compared to previously established nomograms. All 21 patients had bladder volumes at pressures of 30 cm. water or less, which decreased below the 5th percentile as determined by the nomogram. In 7 patients (33%) normal total bladder capacity was achieved at the expense of elevated storage pressures. Pressure specific bladder volume provides a better measure of bladder storage function than total bladder capacity because it relates volume to intravesical pressure, does not rely on a subjective end point to bladder filling, and is objective and reproducible.

Bladder augmentation: ureterocystoplasty versus ileocystoplasty

The primary advantages of augmentation ureterocystoplasty include the absence of mucus, lack of electrolyte absorption from the augmenting segment and the avoidance of gastrointestinal complications. We tested whether the ureteral patch offers sufficient biomaterial to increase adequately the storage efficiency of dysfunctional bladders. Between April 1989 and November 1992, 8 children with unilaterally dilated and tortuous ureters underwent bladder augmentation using detubularized reconfigured megaureter. Clinical and urodynamic outcomes were compared between these patients and a control group of 8 children matched in age and diagnosis who had undergone ileocystoplasty during the same time. Total bladder capacity, pressure specific bladder volume at pressure less than 30 cm. water, dynamic analysis of bladder compliance, continence and upper tract status were compared between the 2 groups before and after augmentation. Preoperatively, all 16 patients were incontinent with high pressure, small capacity bladders, and all had upper tract changes. Postoperatively, the mean total bladder capacity was 417 ml. in the ureterocystoplasty group and 381 ml. in the ileocystoplasty group (p > 0.05), while the mean pressure specific bladder volume was 413 and 380 ml. (p > 0.05), respectively. Pressure specific bladder volume and dynamic bladder compliance were normal in 7 of 8 patients (87.5%) in the ureterocystoplasty group. All patients in the ileocystoplasty group had normal postoperative urodynamics. We conclude that megaureters subtending effete kidneys may be used to improve the storage function of dysfunctional bladders to the same extent as that achieved with ileum without the complications pursuant to ileocystoplasty, and that the improvement is maintained long term.

Intrarenal resistive index correlates with renal pelvis pressure

Elevation in the intrarenal resistive index has been suggested by many to be a physiological parameter useful for detecting functionally significant hydronephrosis. It is currently unknown whether the intrarenal resistive index changes truly reflect the changes in collecting system pressure or whether they are simply a coincidental epiphenomenon. The purpose of this study is to establish the relationship between intrarenal resistive index and collecting system pressure. Between August 1992 and October 1993, 9 patients younger than 1 year underwent a percutaneous pressure-flow study as part of hydronephrosis evaluation. During the pressure-flow study intrarenal resistive index was measured serially with simultaneous renal pelvis pressure readings. In all patients the index increased as the renal pelvis pressure increased. Furthermore, using the experimentally derived proximal tubular pressure of 14 cm. water as the probable threshold for functionally normal collecting system pressure, it was found that all intrarenal indexes of 82% or less corresponded to renal pelvis pressures of less than 14 cm. water, while all of those greater than 82% corresponded to renal pelvis pressures greater than 14 cm. water. By combining several lines of evidence, it appears probable that as maximal diuresis induced by physiological and pharmacological means leads to acute transient elevation in renal pelvis pressure in a functionally obstructed collecting system, the intrarenal resistive index is capable of reflecting this dynamic elevation in renal pelvis pressure and potentially able to distinguish physiologically significant upper urinary tract obstruction from nonobstructive dilatation.

The role of retroperitoneal lymphadenectomy in localized paratesticular rhabdomyosarcoma

Between 1985 and 1990, 10 cases of embryonal paratesticular rhabdomyosarcoma were treated at our institution. Patient age ranged from 5 months to 16 years at presentation (mean 8.7 years). Chest and abdominal computerized tomography (CT) was performed on all patients. Lymphangiography was performed on 2 patients, and 6 underwent retroperitoneal lymphadenectomy, due to suspicious CT (2) and a positive lymphangiogram (1). All 6 patients had pathologically negative nodes, and they received vincristine, actinomycin D and cyclophosphamide for 8 to 13 months (mean 10.6 months). Four patients also received doxorubicin. The 10 patients are alive and the disease is in complete remission for a mean 6.02-year disease-free survival. These data support the hypothesis that retroperitoneal lymphadenectomy can be avoided for paratesticular rhabdomyosarcoma after radical inguinal orchiectomy when CT is negative for nodal involvement.

Contradictory supranormal differential renal function during nuclear renographic investigation of hydroureteronephrosis

We selected a group of children with unilateral hydroureteronephrosis to assess the significance of the differential renal function as determined by nuclear renography as a factor in defining obstructive dilatation. All children who presented to our institution during a 21-month period with unilateral hydroureteronephrosis and a normal contralateral kidney were reviewed. Patients with reflux or bladder pathology were excluded, resulting in 13 evaluable patients younger than age 2 years. Diuretic renography was performed using 99mtechnetium-diethylenetriaminepentaacetic acid in accordance with the well tempered renogram. Ancillary studies included voiding cystourethrography, ultrasonography and/or excretory urography. Of the 13 patients 5 had a differential function greater than 55% in the hydronephrotic kidney. Ten of the 13 patients, including the 5 with supranormal function, underwent surgical correction in the form of ureteral reimplantation for recurrent infections, increasing hydronephrosis, decreasing or decreased function and loss of parenchyma. Stenotic distal adynamic ureteral segments with proximal dilatation were confirmed in all cases. The implication by nuclear renography that a dilated kidney has better function than its morphologically normal counterpart is at variance with any available clinical or experimental data. The etiology of this apparently elevated function is unclear and its presence on a renographic study should not be interpreted as suggestive that the kidney is free of risk of nephron loss. Management decisions should not be based solely on the differential function as determined by nuclear renography.

Can previously relocated penile skin be successfully used for salvage hypospadias repair?

Between 1986 and 1992, 39 boys underwent 44 pedicle flap urethroplasties as a salvage procedure using penile skin that had been relocated during prior hypospadias repair(s). All previous operations had resulted in a meatus in an unacceptable position. The salvage pedicle flap procedure used for these boys was either a Mathieu urethroplasty or an island flap repair. Of 28 patients who underwent salvage Mathieu urethroplasty 20 (71%) required no further surgery, 4 had strictures or fistulas repaired and 4 (14%) required further urethral reconstruction, including 1 island flap and 2 Mathieu operations. Of 16 boys who underwent salvage island flap procedures 7 (43%) required no further treatment, 4 had fistulas, 2 had had urethral strictures and 4 had a subcoronal meatus, of whom 3 underwent further urethral reconstruction, including 2 Mathieu and 1 Thiersch-Duplay operations. We defined overall success as ultimately having a functional urethra without persistent fistulas or strictures and a cosmetically acceptable glanular meatus. Excluding 2 patients who are awaiting fistula repair, 34 of 37 evaluable cases (92%) were successfully repaired. We conclude that relocated penile skin can be used successfully to base a pedicle flap for salvage hypospadias repair.

Loss of elasticity in dysfunctional bladders: urodynamic and histochemical correlation

To store adequate volumes of urine at low safe pressures an elastic bladder wall is required. We developed 2 new techniques to measure this ability in our urodynamic laboratory: pressure specific bladder volume, which measures the bladder capacity at a given pressure, and dynamic analysis of bladder compliance. Recently, morphometric and histochemical techniques have been used to determine the relative volume of connective tissue in the bladder wall and to measure the 2 major types (I and III) of collagen within the bladder wall. These methods quantitate 3 parameters of bladder ultrastructure: 1) relative volume of per cent connective tissue, 2) ratio of connective tissue to smooth muscle and 3) ratio of type III to type I collagen. These parameters have been shown to be abnormally elevated in patients with dysfunctional bladders compared to normals. The purpose of the study was to describe the ultrastructural changes that occur in the wall of dysfunctional bladders and to determine the ability of these new urodynamic techniques to detect reliably the clinical effect of these histological changes. The study included 29 consecutive patients with dysfunctional bladders necessitating bladder augmentation. All patients had upper tract changes and/or were incontinent despite treatment with clean intermittent catheterization and pharmacotherapy. Preoperative urodynamic evaluation included measurement of the total bladder capacity, pressure specific bladder volume and dynamic analysis of bladder compliance. Full thickness bladder biopsies were obtained from the dome of the bladders during augmentation. The per cent connective tissue and the ratio of connective tissue to smooth muscle were determined for all patients, and 4 unselected patients from this group had the ratio of type III to type I collagen determined. These histological results were compared to previously established normal values. All 29 patients had a decreased pressure specific bladder volume and dynamic analysis of bladder compliance, whereas 9 had a normal total bladder capacity. The per cent connective tissue was 35.19 +/- 2.84 and ratio of connective tissue to smooth muscle was 0.60 +/- 0.08 compared to normal values of 10.6 +/- 0.020 and 0.131 +/- 0.021, respectively (p < 0.05). Ratio of type III to type I collagen was also significantly elevated in the 4 samples analyzed (30.53 +/- 1.37 versus 24.00 +/- 2.50, p < 0.05). We conclude that poor storage function of poorly compliant bladders is secondary to an alteration in the connective tissue content of the bladder wall. Furthermore, these pathological ultrastructural changes are universally reflected by an abnormally low pressure specific bladder volume and dynamic analysis of bladder compliance. This strong association validates the use of these parameters and suggests that they are urodynamic indicators of a loss of elasticity in bladder wall.

Iliac osteotomy: a model to compare the options in bladder and cloacal exstrophy reconstruction

Bladder exstrophy and cloacal exstrophy present challenging reconstructive problems. Traditionally, bilateral posterior iliac osteotomy has been performed in the majority of patients undergoing primary closure for these abnormalities. Recently, 2 anterior osteotomy approaches have been proposed: 1) incision of the ilium transversely above the acetabulum (transverse osteotomy) and 2) incision of the superior ramus of the pubis (superior ramus osteotomy). We devised a new anterior mid-iliac diagonal osteotomy that provides a more functional pelvic closure. To provide a fair comparison of the procedures we developed a pelvic exstrophy model based on data from a 3-dimensional computerized tomogram of a 3-year-old patient with classical bladder exstrophy. The different osteotomies were then performed on the model and the results were compared. Our new anterior mid-iliac diagonal osteotomy correction allowed the best surgical approach, provided the best correction of the flattened ilia bony deformities, was performed in the thinnest area of marrow bone and resulted in the best pelvic symmetry.

A new technique for dynamic analysis of bladder compliance

We propose an alternative method of measuring compliance that takes into account the multiple phases of bladder filling. We describe our new technique, dynamic compliance analysis, and evaluate its clinical applicability. To perform the analysis we digitized a cystometrogram curve at a sampling rate of 2 samples per second using an MS-DOS computer system. A program designed to retrieve the stored data was used to analyze the subtracted bladder pressure. The result yielded a value of compliance every half second that was then plotted on an x-y graph, with instantaneous compliance as the dependent variable and per cent of total volume infused as the independent variable. To determine the clinical applicability of this technique we chose 63 curves from clinically normal patients. The results of the dynamic compliance analyses were predictable. The dynamic compliance values for the normal group had a minimum that was always greater than 10 ml./cm. water throughout the tonus limb (phase 2) of the cystometrogram. We conclude that dynamic compliance analysis yields more information about bladder response during filling, similar to the stress-strain curve used in the study of solid mechanics.

Effectiveness of preoperative chemotherapy in the treatment of Wilms tumor with vena caval and intracardiac extension

Surgical treatment of Wilms tumor with vena caval and intracardiac extension is challenging, often requiring cardiopulmonary bypass. We report the response to preoperative chemotherapy in 3 patients following a protocol at our hospital. The tumor thrombus was limited to the inferior vena cava in 2 patients and extended to the right atrium in 1. All 3 patients had marked reduction or complete eradication of the venous thrombus, facilitating the final surgical procedure. The patients are disease-free 18 months to 7 years after the initial treatment. Our protocol involves initial radiographic staging followed by needle biopsy, chemotherapy, repeat radiographic staging, definitive resection and additional chemotherapy. Our results confirm the effectiveness of this approach, which appears to decrease morbidity associated with intracaval and intra-atrial tumor extension.

Ureteral bladder augmentation

Virtually all segments of the gastrointestinal tract have been used successfully in augmentation cystoplasty. The complications inherent in enterocystoplasty are well described. Megaureters subtending effete kidneys (poorly or nonfunctioning) provide a novel and excellent source of augmentation material with urothelium and muscular backing, free of the electrolyte and acid base disturbances, and mucus production that plague enterocystoplasty. Augmentation cystoplasty using detubularized, reconfigured, otherwise disposable megaureter, with or without ipsilateral total or partial nephrectomy, was performed in 16 patients (mean age 8.8 years, range 1 to 25) with inadequate and dysfunctional bladders. Postoperative followup varied between 8 and 38 months (mean 22). The overall renal function and radiographic appearance of the remaining upper tracts have remained stable or improved in all patients. Of the 16 patients 15 require intermittent catheterization and 1 voids spontaneously. Ten patients are continent day and night, 5 have improved continence (4 damp at night and 1 stress incontinence) and 1 has failed to gain continence despite good capacity and compliance. Complete postoperative urodynamic evaluations in 12 of 13 patients show good capacity, low pressure bladders with no instability. Complications occurred in 5 patients, including transient urine extravasation in 2, contralateral ureterovesical obstruction in 2 and Mitrofanoff stomal stenosis in 1. Augmentation ureterocystoplasty combines the benefits common to all enterocystoplasties without adding any of the untoward complications or risks associated with nonurothelial augmentations.

What volume can a child normally store in the bladder at a safe pressure?

To determine what volume a child can normally store in the bladder at a safe pressure 923 pediatric urodynamic studies were reviewed, and 69 examinations done on 17 boys and 52 girls were considered normal. Patient ages were recorded and body surface areas were calculated. A continuous intermediate flow water cystometrogram had been performed. Total bladder capacity in milliliters, full resting pressures (cm. water), and the volumes (milliliters) and percentages of the total bladder capacity stored at detrusor pressures of less than 10, 20, 30 and 35 cm. water were measured. We found that 98.1% of the total bladder capacity could be stored at a detrusor pressure of less than 20 cm. water in more than 95% of the children independently of age or body surface area and 99.9% could be stored at a detrusor pressure of less than 30 cm. water. An approximation of the minimal acceptable total bladder capacity for age can be calculated by 16(age) + 70 in ml. According to our results, we proposed criteria for good storage characteristics of the bladder in children.

Hypertension following primary bladder closure for vesical exstrophy

Since the initiation of staged reconstruction for bladder exstrophy, hypertension has been a known complication of the procedure. The etiology of the elevation in blood pressure was presumably secondary to ureteral dysfunction caused by edema at the ureterovesical junction and secondary renal obstruction. This report details the clinical course of three patients who developed significant hypertension following primary bladder closure with posterior iliac osteotomies and bony immobilization by skin traction. None of the patients had urinary obstruction and all had their hypertension alleviated by removal of the traction. The presumed etiology of the elevated blood pressure within these patients is similar to that experimentally produce by inappropriately applied traction resulting in tension on the sciatic nerve and reflex induced vasoconstriction. The need to maintain appropriately applied traction and the necessity of monitoring the postoperative blood pressure is stressed.

Radiographic and serologic correlates of azotemia in patients with posterior urethral valves

A retrospective statistical analysis with a minimum followup of 10 years was done on 102 patients who presented in early childhood with posterior urethral valves. All patients were treated with initial bladder drainage. Factors correlating with the development of renal failure were evaluated. No patient with a normal kidney on 1 side had renal failure. Calculated glomerular filtration rate was significantly higher in patients who retained adequate renal function (80.7 +/- 17.8 ml. per minute per 1.73 m.2), as compared with those who had renal failure (18.6 +/- 9.6 ml. per minute per 1.73 m.2). Patients with renal failure also had a significantly higher serum creatinine level at stabilization (2.0 +/- 0.8 mg./dl.) than those who had adequate renal function (0.5 +/- 0.2 mg./dl.). The presence of bilateral high grade vesicoureteral reflux, hydronephrosis and nonfunction was significantly higher in patients with renal failure. Patient age at presentation was not a significant factor. These data represent a guideline for the prognosis and management protocols of infants with dilated upper urinary tracts and posterior urethral valves.

The efficiency of bladder emptying in the prune belly syndrome

From 1956 to 1991, 49 cases of the prune belly syndrome were seen at our institution. Voiding information and/or 1 or more urodynamic studies were available in 30 male and 4 female patients. Analysis of multiple urodynamic studies during long-term followup periods ranging from 6 months to 19 years, with particular regard to any reconstructive procedures performed, revealed that voiding in the prune belly syndrome is variable, with 44% of the patients achieving spontaneous voiding and 56% requiring clean intermittent catheterization. The ability to void or need for clean intermittent catheterization was by no means permanent, indicating the need for meticulous followup. The 3 distinct voiding patterns observed included an approximately normal pattern, prolonged voiding with a low peak and an intermittent pattern. These 3 voiding patterns did not correlate with residual volumes. Comparison of urodynamic voiding parameters between reconstructed voiding patients and nonreconstructed voiding patients did not show significant differences.