Search

To investigate whether orchiopexies are occurring later than recommended by American Academy of Pediatrics 1996 guidelines (around age 1). Adherence to guidelines is poorly studied.The main cohort consisted of 4103 boys insured from birth (Innovus i3, insurance claims database). The complementary cohort consisted of 17 010 insured and noninsured boys (Pediatric Health Information System, PHIS). The inclusion criteria was age ≤ 5 years at time of International Classification of Disease, 9th revision-defined cryptorchidism diagnosis. The primary outcome was timely surgery (orchiopexy by age 18 months).In Innovus, 87% of boys who underwent an orchiopexy had a timely orchiopexy. Of those who did not undergo surgery (n = 2738), 90% had at least 1 subsequent well-care visit. Those who underwent timely surgery were referred to a surgeon at a younger age compared with those who underwent late surgery (4.1 vs 16.1 months, P.00005). Predictors of timely surgery were number of well-care visits (odds ratio 1.5, 95% confidence interval 1.3-1.7), continuity of primary care (odds ratio 1.9, 95% confidence interval 1.3-2.7), and use of laparoscopy (odds ratio 4.5, 95% confidence interval 1.4-14.9). Family/internal medicine as referring provider was predictive of delayed surgery (odds ratio 0.5, 95% confidence interval 0.3-0.8). In the Pediatric Health Information System, 61% of those with private insurance had timely surgery compared with 54% of those without private insurance (P.0001).We found an unexpectedly high adherence to guidelines in our continuously insured since birth Innovus population. Primary care continuity and well-care visits were associated with timely surgery. Further studies can confirm these findings in nonprivately insured patients with the ultimate goal of instituting quality improvement initiatives.

Following bladder augmentation, patients are at significant risk for bladder calculi. We present our experience with a minimally invasive treatment approach using endoscopically assisted percutaneous cystolithotomy.A retrospective chart review identified 74 patients who underwent percutaneous cystolithotomy following bladder augmentation between 2002 and 2009. Cystogram was performed to determine the ideal location for percutaneous bladder access and a guidewire was inserted in the bladder through a bile needle. A balloon dilator was used to place a 30Fr sheath. Rigid cystoscopy with a 26Fr nephroscope allowed stone treatment by basketing and ultrasonic lithotripsy. A suprapubic 22Fr catheter was then placed. Patients were seen on postoperative day 14 and abdominal ultrasound was performed. If no significant residual calculi were visualized, the suprapubic tube was removed.Mean +/- SD patient age at operation was 20 +/- 10.7 months (range 4 to 40). Mean +/- SD time between bladder augmentation and percutaneous cystolithotomy was 4.8 +/- 2.05 years. Of the patients 38 (51%) were male and 36 (49%) were female. Mean +/- SD number of stones per patient was 4.6 +/- 7.8 (range 1 to 60). Ultrasonic lithotripsy was performed in 49 cases (66%). In 25 cases (34%) only stone basketing was performed. A total of 70 patients (95%) were stone-free on abdominal plain film at 14 days. Of the procedures 24 (32%) were performed on an outpatient basis and 50 were performed on an inpatient basis with a mean +/- SD hospital stay of 1.3 +/- 2.7 days (range 1 to 21). There were 9 minor complications noted (12%).Endoscopic percutaneous cystolithotomy offers a safe and effective treatment option for bladder calculi in reconstructed bladders and is the preferred method at our institution.

OBJECTIVE To show, for pressure-time data from cystometrography (CMG), the potential practical clinical application of automatically identified, displayed, analysed and quantified compliance and contractility, as undesirable high-pressure detrusor storage may be caused by inefficient compliance or uninhibited contractions (UNC). MATERIAL AND METHODS Bladder contractility was measured by UNC and compliance by relaxed-state detrusor pressure (RSDP), i.e. the detrusor (bladder-abdominal) pressure with all UNC removed. Forty-one CMG examinations were used retrospectively to: (i) validate the separation and identification, by comparing the resulting separate graphs (data) of UNC and RSDP with an expanded time scale for raw vesical and rectal data; (ii) show that the separation is correct by examples; and (iii) show the potential practical utility by results for typical cases. RESULTS Separation into RSDP and UNC was correctly identified and plotted. The examples showed the utility and four types of UNC (‘high’, contractions of >25 cmH2O of long duration; ‘medium’, >25 cmH2O of short duration; ‘low’, 4–25 cmH2O of short duration; and ‘frequent’, of 2–6 cmH2O). CONCLUSIONS UNCs as small as 2 cmH2O can be detected and measured. The explicit enhanced estimate of compliance and contractility will be useful in the follow-up when comparing different patients and studies, and assist in more appropriate diagnosis and treatment. Because the treatment for bladders with poor contractility differs greatly from those with detrusor instability, the ability to reliably and accurately differentiate between these causes is important.

S ince the mid-1980s, minimally invasive surgery has evolved with the creation of such devices as 3-mm instruments and miniature probes for percutaneous therapies. However, one must ask, “When does it end? How small is too small?” This fundamental question is the foundation of microelectromechanical systems or MEMS technology. Although images of the 1966 film Fantastic Voyage, in which a group of humans are miniaturized and travel within the vascular system of a human, may come to mind, MEMS technology is in no way science fiction. Rather, it is the integration of decades of knowledge from many fields that allows us to interact with the physical world at a level once thought to be impossible. MEMS technology is based on techniques used in the semiconductor fabrication industry and has generated significant enthusiasm among physicians and surgeons in recent years. At their most basic levels, MEMS are devices with dimensions of micrometers to a few millimeters that combine electrical and mechanical components to acquire data or do work. An exhaustive review of the biomedical applications of MEMS is beyond the scope of this review. Rather, its purpose is to introduce the urologist to this exciting technology and present the existing and future ways in which this technology will aid the clinician.

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.

INTRODUCTION AND OBJECTIVES: Long-term indwelling urinary catheters are susceptible to blockage due to formation of crystalline biofilms by urease-producing microorganisms such as Proteus mirabilis. An in vitro catheter biofilm model (CBM) was developed to compare current methods for maintaining urinary catheter patency. We compared various bladder irrigation solutions or antimicrobial-coated urinary catheters, versus a novel anti-microbial catheter irrigation solution containing auriclosene (N,N-dichloro-2,2-dimethyltaurine; formerly designated NVC-422). METHODS: CBM units were fed artificial urine at 0.5 mL per min. The artificial bladder chamber was inoculated with 10 8 colony forming units (CFU) of P. mirabilis and biofilm was allowed to establish for 48 hours before daily treatments commenced. A single treatment consisted of two sequential 50-mL irrigations. Each irrigation was retained in the catheter for 15 min and then drained, with a 30-min washout period between the two irrigations. Experiments were conducted for up to 10 days or until catheter blockage. The pH of the effluent, CFU counts in the bladder chamber and the time to catheter blockage were recorded. The area of catheter encrustation was measured using Stereo Zoom imaging. RESULTS: Inoculation of the CBM reactor with 10 8 CFU of P. mirabilis resulted in blockage of the urinary catheters within 5 days. The use of silver-hydrogel or nitrofurazone-coated catheters did not extend the period of catheter patency. Catheters irrigated with 0.25% acetic acid, 10 mM acetate-buffered saline or isotonic saline blocked at the same rate as untreated catheters. Catheter irrigation with a citrate-buffered formulation of 0.2% auriclosene resulted in complete eradication of P. mirabilis biofilm within one treatment day. In contrast, daily irrigations of infected catheters with 0.2% auriclosene in 10 mM acetate-buffered saline (at pH 4) or Renacidin ® Irrigation Solution had no effect on P. mirabilis colonization of the bladder chamber, even though catheter patency was maintained throughout 10-day studies. CONCLUSIONS: Irrigation with the rapidly bactericidal antimicrobial auriclosene in a buffered acidic formulation - termed Auriclosene Irrigation Solution - significantly enhanced catheter patency in vitro versus other irrigation solutions and antimicrobial- coated urinary catheters. Clinical evaluation of Auriclosene Irrigation Solution is ongoing. Results (continued) Abstract

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.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.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.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.

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.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.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.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.

We reviewed the surgical results of the management of bilateral single ureteral ectopia, a rare congenital cause of severe urinary incontinence.We reviewed the records of 6 girls and 1 male infant who presented to 1 institution with this diagnosis in a 10-year period.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.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.

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.

To: (i) calculate traditional compliance (CTrad) for a normal bladder by DeltaV/DeltaPdet, where DeltaV is the mean volumetric capacity and DeltaPdet is the detrusor pressure rise; (ii) assess its usefulness; (iii) identify the variables that are necessary for correctly assessing bladder compliance; and (iv) using these variables, report a method that, because it includes the effect of patient age, sex and size, correctly assesses compliance for management strategies.We obtained the mean volumetric capacity of a normal bladder (V(cap,NL)) and the mean detrusor pressure rise (P(cap,NL)) on filling a normal bladder to its volumetric capacity from our and other published work; (ii) calculated CTrad for a normal bladder; (ii) showed that the variables necessary for assessing compliance correctly are DeltaV, DeltaPdet, V(cap,NL), and P(cap,NL); and (iii) showed that the relationship among these is the dimensionless number, NWahl(-1), calculated as (DeltaV/V(cap,NL))/(DeltaPdet/P(cap,NL)). This value for individuals with a normal bladder was calculated, tabulated and graphed.Because a normal individual's bladder capacity increases with age while the detrusor pressure increase does not, CTrad increases with age and therefore cannot be used for assessing compliance. Published data substantiate our result that CTrad for an individual with a normal bladder varies from 6.3 at 0.5 years old to 90 mL/cmH2O at 18 years old. NWahl(-1) correctly assesses bladder compliance because it is the same for all normal cases; consequently NWahl(-1) is more practical for clinical use.Bladder compliance is standardized using DeltaV, DeltaPdet, V(cap,NL), and P(cap,NL) to give NWahl(-1), and bladder compliance is usefully reported using this value.

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%, p0.0001). 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.

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 (p0.0001). 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.

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 (p0.05).

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.

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 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 (p0.05), while the mean pressure specific bladder volume was 413 and 380 ml. (p0.05), 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.

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.

The current diagnosis and management of pediatric urinary tract infection is reviewed along with recent developments in the pathophysiology of urinary infection. We discuss current knowledge of host and bacterial factors and how these influence our management in terms of investigation and treatment.

We evaluated the outcome in 19 patients who underwent bladder neck reconstruction by lengthening, narrowing and tightening the bladder neck with a combined tubularized posterior urethroplasty and circumferential fascial wrap.We reviewed the records of all patients who underwent bladder neck lengthening, narrowing and tightening between April 1996 and November 2002. Preoperative urodynamic and radiographic data were available on all patients. The surgical technique involved retroperitoneal exposure of the bladder neck with a tubularized posterior urethroplasty over a urethral catheter. The reconstructed urethra was then circumferentially wrapped with a fitted piece of cadaveric fascia.Of the 19 patients 15 remain completely continent at a mean ± SD followup of 35.5 ± 29.1 months. Three patients underwent secondary reconstruction, including bladder neck ligation in all 3 and secondary enterocystoplasty in 2. No patient experienced difficult intermittent catheterization via the urethra postoperatively.Bladder neck lengthening, narrowing and tightening is effective for managing neurogenic sphincteric incontinence. Outcomes are comparable with those of other reconstructive procedures.

Voiding cystourethrography is a routine component in evaluating children awaiting renal transplantation. We examined whether this assessment is necessary in children with renal failure due to dysplasia/aplasia/hypoplasia syndrome and unknown etiology, which account for up to 25% of those with renal failure requiring renal replacement therapies.We performed an institutional review board approved, retrospective review of 191 children undergoing transplantation between 2002 and 2007. We reviewed clinical factors associated with positive findings on voiding cystourethrogram. We also reviewed cystography results in children with chronic kidney disease due to renal dysplasia and unknown etiology.We identified 113 boys and 78 girls who underwent renal transplantation during the study period. Pre-transplant voiding cystourethrography was documented in 108 children (57%). Predictors of positive pre-transplant results included history of hydronephrosis, urinary tract infections and renal failure due to urological causes. No pre-transplant cystogram was positive in children with renal failure due to dysplasia or unknown etiology.We recommend selective use of voiding cystourethrography to evaluate children awaiting renal transplantation. We continue to support performing this test in children with renal failure due to urological causes and those with a history of urinary tract infection, hydronephrosis or voiding dysfunction. In the absence of these findings children with renal failure due to renal dysplasia/aplasia/hypoplasia syndrome or unknown etiology need not undergo pre-transplant voiding cystourethrography.

The magnetic resonance imaging (MRI) appearance of a cystic, partially differentiated nephroblastoma is described, together with pathologic correlation. The difficulty in reaching a correct preoperative diagnosis even with multimodal imaging techniques is emphasized. MRI is an adjunct to ultrasonography and may be superior to computerized tomography (CT) scan in the evaluation of a child with multiloculated cystic renal mass.

Posterior urethral valves have a broad spectrum of clinical severity determined by the degree and reversibility of the long stepwise sequence of secondary pathology. Neonatal azotemia and severe bilateral reflux are particularly important negative prognostic factors. In the mild cases, valve ablation with or without delayed reconstruction is good therapy. In the very severe cases, our interpretation of all the clinical and experimental information now available suggests that the time interval and the level of decompression are extremely important. Achievement of consistent low caliceal pressure without stasis and infections should be achieved as soon as possible. We do not agree with the philosophy of "valve ablation and wait and see" for secondary reconstruction as applied to the severe cases. An analogous philosophy would be treating all respiratory infections as upper respiratory infections and applying aggressive appropriate therapy for pneumonia only if the patient does not respond clinically. However, all controversy aside, the management of neonatal infants with posterior urethral valves remains a difficult and challenging problem for us all. The real challenge will be to improve published management results to the point that the family faced with decisions regarding an in utero diagnosis of posterior urethral valves will have enough hope to continue the pregnancy.

Severe hypertension developed secondary to renal artery stenosis in 11 of 229 children who received a renal allograft. Renal artery stenosis was suspected because of de novo development of hypertension or exacerbation of pre-existing hypertension, which was detected 1 to 24 months after transplantation. Selective renal angiography was performed 2 to 74 months after transplantation (mean 13 months). Follow-up was 1 to 8 years (mean 2.5 years). The stenosis involved the anastomosis in 5 patients and was distal to the anastomosis in 6. One graft had an arteriovenous malformation. Seven grafts were suitable for vessel dilation; percutaneous transluminal angioplasty was partially successful in 4 cases in which the stenosis occurred at the anastomosis. The remaining patients were treated with medical therapy alone and the grafts were not lost. Our findings suggest that strictures distal to the anastomosis rarely are amenable to percutaneous transluminal angioplasty and should be treated medically whenever possible. Strictures at the anastomosis respond to vessel dilation but antihypertensive medication also often is required. An operation should be reserved for patients who do not respond to these measures.

The significance of early renal graft function on long-term transplant survival is controversial. From our pediatric renal transplant population we studied 151 children who had an initial cadaveric rehal transplant, were dependent on dialysis before transplantation and were 5 to 19 years old at transplantation. We used dependence upon dialysis as the parameter for early graft function.There was a statistically significant difference in long-term graft survival between patients who were independent of and dependent on dialysis at 1 week and 1 month postoperatively. Our results show that early renal graft function is important for long-term graft survival. All efforts should be directed to obtaining early renal graft function by proper organ procurement, storage, operative technique and aggressive postoperative management. (J. Urol., 143: 326–329, 1990).

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 ...

Recent reports of outcomes of bladder neck closure for neurogenic urinary incontinence reveal poor initial continence and high vesicourethral fistula rates. We evaluated a large series of patients who underwent complete transection and closure of the bladder neck with modified abdominal stoma creation.The medical records of 52 consecutive patients (23 males and 29 females) undergoing bladder neck closure by a single surgeon between July 1996 and January 2003 were reviewed. Mean follow up was 20 months (range 2-68 months) and mean age was 13.9 years (range 1.5-58 years). Forty-two patients (81%) underwent concomitant bladder augmentation. Catheterizable stomas included 46 appendicovesicostomies (88%) and six Monti tubes (12%). Of the 52 patients, 22 were confined to wheelchairs (42%), and the majority of patients had spinal cord pathology (40/52, 77%). Mean preoperative vesical leak point pressure was 25 cm/H(2)O (range 4-69 cm/H(2)O).Complete postoperative urinary continence was achieved in 44 patients (88%) after one procedure. Of the six patients who were incontinent (12%), one had a vesicourethral fistula (2%) and five had incontinence at the urinary diversion stoma (10%). Twelve of 50 patients had urinary stomal stenosis (24%), with six requiring urgent evaluation (12%) and six requiring surgical revision (12%). Postoperative urinary continence was unknown in two patients due to inadequate follow-up data.Our findings suggest that bladder neck closure is a safe and effective method of achieving urinary continence in children with neurogenic voiding dysfunction. While there are risks of stomal stenosis and fistula formation, modifications in surgical technique may reduce them to acceptable levels.

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 percent, erections were straight in 100 percent, and urinary streams were of good quality and without fistula in 100 percent 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 mobili...

OBJECTIVES To: (i) calculate traditional compliance (CTrad) for a normal bladder by DeltaV/DeltaPdet, where DeltaV is the mean volumetric capacity and DeltaPdet is the detrusor pressure rise; (ii) assess its usefulness; (iii) identify the variables that are necessary for correctly assessing bladder compliance; and (iv) using these variables, report a method that, because it includes the effect of patient age, sex and size, correctly assesses compliance for management strategies. METHODS We obtained the mean volumetric capacity of a normal bladder (V(cap,NL)) and the mean detrusor pressure rise (P(cap,NL)) on filling a normal bladder to its volumetric capacity from our and other published work; (ii) calculated CTrad for a normal bladder; (ii) showed that the variables necessary for assessing compliance correctly are DeltaV, DeltaPdet, V(cap,NL), and P(cap,NL); and (iii) showed that the relationship among these is the dimensionless number, NWahl(-1), calculated as (DeltaV/V(cap,NL))/(DeltaPdet/P(cap,NL)). This value for individuals with a normal bladder was calculated, tabulated and graphed. RESULTS Because a normal individual's bladder capacity increases with age while the detrusor pressure increase does not, CTrad increases with age and therefore cannot be used for assessing compliance. Published data substantiate our result that CTrad for an individual with a normal bladder varies from 6.3 at 0.5 years old to 90 mL/cmH2O at 18 years old. NWahl(-1) correctly assesses bladder compliance because it is the same for all normal cases; consequently NWahl(-1) is more practical for clinical use. CONCLUSIONS Bladder compliance is standardized using DeltaV, DeltaPdet, V(cap,NL), and P(cap,NL) to give NWahl(-1), and bladder compliance is usefully reported using this value.

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.

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 less than 0.05)...

To test the neorethra 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 percent) had peak flows within the normal range and 25 (31 percent) had peak flows below the normal range. Of the 51 boys who never had fistulas and/or strictures 37 (73 percent) had normal flows while 18 of 29 (62 percent) who underwent fistula and/or stricture repairs had normal flows (p greater than 0.05). Residual volume was less than...

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.

A highly select group of 31 patients presenting with urinary incontinence failed to respond to conservative management and were found to have unstable bladders and spina bifida occulta. After thorough evaluation they were suspected of having neurogenic bladder dysfunction possibly due to a tethered cord. Following division of the filum terminale daytime incontinence resolved in 72%, urodynamic detrusor hyperreflexia disappeared in 59% and bladder compliance improved in 66% of the patients. The operation was well tolerated and did not result in any neurological complications. The clinical, radiological and urodynamic characteristics of these patients before and after treatment are reported.

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.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.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.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.

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. Twentyseven 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.

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.

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

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.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.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).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.

We examined the pressure dynamics of hydronephrotic kidneys after elevated renal pelvic pressure developed.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.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 (p0.0001). Diuretic nuclear renography half-lives had no correlation with collecting system pressure dynamics.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.

Objective To determine the detrusor pressure rise of a normal bladder (P(cap,NL)) when filled to capacity. Patients and methods Twenty-four patients with an apparently normal bladder, i.e. with symptoms but whose cystometrogram (CMG) showed no pathology of any kind and a near-normal pressure vs volume plot, were selected from 218 clinical CMGs. A straight line was fitted to the PV plot of these CMGs and then the P(cap,NL) calculated, e.g. by a straight line extending to the point of the normal expected cystometric bladder capacity (V(cap.NL)). Published data relative to P(cap,NL) were evaluated and compared with the values obtained. Results The mean (range) P(cap,NL) was 6 (4.5-7) cmH2O for patients with apparently normal bladders infused at the maximum physiological diuresis (MPD). This value was substantiated by three other studies of published values. The P(cap,NL) was 6 cmH2O at infusion rates of 10% of glomerular filtration rate (GFR), 10 cmH2O at 20% of GFR and 7-15 cmH2O for 3-10 times the infusion rate of 10% of GFR. Conclusion P(cap,NL) is independent of age, size and sex and, at constant infusion rates of approximately MPD, will be 6. For infusion rates up to 35 mL/min, it is in the range of 6-15 cmH2O.

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 rare situation.

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.

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.