The changing urodynamic pattern in valve bladders during infancy

Assessment of lower urinary tract function in pediatrics using ultrasonography

Ultrasound imaging is a less invasive imaging modality without radiation exposure and is available for repeated tests. It is the gold standard examination for diagnosing and managing disorders of the urinary tract, including lower urinary tract dysfunction (LUTD) in pediatric urology. Ultrasound imaging is effective for screening underlying diseases and determining treatment strategies. Ultrasound examination at the bedside should focus on post-voided residual urine (PVR), bladder wall thickening, renal morphology, and rectal diameter. Since PVR must be tested immediately after voiding, examining infants who cannot complain of the urge to void is difficult. PVR measurement combined with a 4-h voiding observation or alarm system activated by urine is recommended for these infants. Early diagnosis is important because LUTD is associated with the risk of morbid residual urine and high voiding pressure, which can result in renal deterioration, urinary leakage, and febrile urinary tract infection.

Effectiveness of a voiding evaluation technique using a diaper equipped with a urination-activated alarm system to assess bladder function and voiding patterns in infants

PURPOSE

Four-hour voiding observation is a conventional method for evaluating bladder function in infants. However, it requires a diaper check every 5 min during the observation period, which creates an unusual environment for the infant, making the evaluation of natural urination difficult. This study aimed to investigate the parameters of urination before mature bladder function using a diaper equipped with a urination-activated alarm system.

METHODS

The study participants were 51 infants aged 0-4 years without bladder dysfunction. A urination-activated sensor was used to notify the inspector wirelessly when urination was detected, enabling the immediate assessment of ultrasonically measured residual urine. Bladder capacity was calculated as the sum of both residual urine volume and micturition volume, and the residual urine rate as the residual urine volume divided by bladder capacity.

RESULTS

A total of 36 boys and 15 girls were enrolled. The median (interquartile range) residual urine volume, bladder capacity, and residual urine rate were 3.0 mL (1.1-6.6), 53.0 mL (33.9-75.3), and 7.0% (2.1-15.0), respectively. Infants aged 0-1 and 2-4 years were then classified into Group A (N = 27) and Group B (N = 24), respectively. The residual urine rate was significantly higher in Group A (11.0% [5.4-21.2]) than in Group B (4.8% [0.6-8.9]; p < 0.01).

CONCLUSIONS

Voiding observation using a urination-activated alarm system allowed less invasive analysis in infants and revealed that the residual urine rate decreased with mature bladder function from about 2 years of age.

Posterior urethral valves: Role of prenatal diagnosis and long-term management of bladder function; a single center point of view and review of literature

Posterior Urethral Valves (PUV) are the most common cause of lower urinary tract obstruction. More severe forms are detected early in pregnancy (mainly type I), while other forms are usually discovered later in childhood when investigating lower urinary tract symptoms. Bladder dysfunction is common and is associated with urinary incontinence in about 55% (0%-72%). Despite the removal of the obstruction by urethral valve ablation, pathological changes of the urinary tract can occur with progressive bladder dysfunction, which can cause deterioration of the upper urinary tract as well. For this reason, all children with PUV require long-term follow-up, always until puberty, and in many cases life-long. Therefore, management of PUV is not only limited to obstruction relief, but prevention and treatment of bladder dysfunction, based on urodynamic observations, is paramount. During time, urodynamic patterns may change from detrusor overactivity to decreased compliance/small capacity bladder, to myogenic failure (valve bladder). In the past, an aggressive surgical approach was performed in all patients, and valve resection was considered an emergency procedure. With the development of fetal surgery, vesico-amniotic shunting has been performed as well. Due to improvements of prenatal ultrasound, the presence of PUV is usually already suspected during pregnancy, and subsequent treatment should be performed in high-volume centers, with a multidisciplinary, more conservative approach. This is considered to be more effective and safer. Primary valve ablation is performed after clinical stability and is no longer considered an emergency procedure after birth. During childhood, a multidisciplinary approach (pediatric urologist, nephrologist, urotherapist) is recommended as well in all patients, to improve toilet training, using an advanced urotherapy program with medical treatments and urodynamic evaluations. The aim of this paper is to present our single center experience over 30 years.

Bladder function in children with posterior urethral valves: impact of antenatal versus postnatal diagnosis

Purpose:

Posterior urethral valves (PUVs) are the most common cause of congenital bladder obstruction in boys. Our aim was to assess the impact of early diagnosis and fulguration of PUVs on bladder function and compare their functional and urodynamic outcome with children who underwent delayed intervention.

Materials and Methods:

We retrospectively evaluated 153 patients who underwent primary valve ablation from two tertiary hospitals between 2001 and 2018. Patients have been divided into 2 groups, group 1 included 69 patients who were detected antenatally and underwent early fulguration of PUVs while group 2 included 84 children presented postnatally and underwent delayed valve ablation. The recorded data throughout follow-up in renal function tests, urodynamics and changes in the upper urinary tracts were evaluated and compared.

Results:

Median age at time of valve ablation was 10 days in group 1 and 7 months in group 2. The median follow-up period was 6.5 and 7 years in group 1 and 2, respectively. Chronic kidney disease (CKD) developed in 15 (22%) boys in group 1 while in group 2 it was observed in 31 (37%), p=0.04. While Q-max, mean bladder capacity and post-void residual (PVR) volumes were comparable in both groups, percent PVR was significantly higher in group 2 (3.27 vs. 1.44, p=0.002). Detrusor overactivity was slightly different in both groups (p = 0.07).

Conclusions:

Compared to delayed intervention, primary ablation of PUVs during the early neonatal life possibly provides the optimum chance to have optimum renal function without impact on bladder function.

BOO induces fibrosis and EMT in urothelial cells which can be recapitulated in vitro through elevated storage and voiding pressure cycles

PURPOSE

To determine the unique contributions from elevated voiding and storage pressures in the development of fibrosis and the epithelial-to-mesenchymal transition (EMT) in urothelial cells, and how progressive BOO pressure cycling is an important mechanical cue leading to these pathological changes.

MATERIALS AND METHODS

Urothelial cells isolated from control, SHAM, 2 (acute)- or 6 (chronic)-week BOO rats treated with an inflammasome inhibitor or no drug. Total RNA was isolated and RT-PCR was conducted with custom primers for pro-fibrotic and EMT genes. In separate experiments, a rat urothelial cell line was exposed to cyclic pressure regimes characteristic of acute and chronic BOO in the presence or absence of an inflammasome inhibitor. Following exposure, RT-PCR was conducted, collagen content was determined and intracellular caspase-1 activity was measured.

RESULTS

Urothelial cells isolated from acute and chronic BOO rat models demonstrated expression of pro-fibrotic and EMT genes. Similarly, MYP3 rat urothelial cells subjected to pressure cycling regimes that reflect intravesical pressures in the acute or chronic BOO bladder also demonstrated increased expression of pro-fibrotic and EMT genes, along with elevated soluble collagen. Treatment with inflammasome inhibitors reduced expression of pro-fibrotic genes in the rat model and pressure cycling model but had a limited effect on EMT.

CONCLUSION

These results indicate that acute and chronic BOO pressure cycling are essential in the initiation and progression of fibrosis in the bladder via the NLRP3 inflammasome, but also provide new evidence that there is also an alternative NLRP3-independent pathway leading to EMT and fibrosis.

Urodynamics in Posterior Urethral Valve: Pursuit of prognostication or optimisation

INTRODUCTION

Detrusor dysfunction is known to persist in several patients of Posterior Urethral Valve (PUV) after successful fulguration leading to progressive deterioration of renal function. Persistent bladder outlet obstruction (BOO) in the form of bladder neck hypertrophy, residual valves or strictures may contribute to progressive detrusor dysfunction. These are assessed radiologically or cystoscopically and are managed variedly by anticholinergics, alpha-adrenergic blockers or even bladder neck incision. Unfortunately, currently we do not have any objective measures to evaluate the degree of BOO in children or follow treatment outcome of any such measures.

OBJECTIVE

To assess the feasibility of pressure flow studies in children and proposition of an age independent index to quantify outflow parameters.

STUDY DESIGN

We retrospectively studied the urodynamic data of the follow up cases of PUV who had been referred to us for urodynamic evaluation. Free flow uroflowmetries and filling and voiding cystometrogram were performed as per recommended protocol. Parameters like Adjusted Bladder Capacity (ABC = Voided volume + post void residue; expressed as percentage of expected bladder capacity {EBC}), overactivity, compliance, Qmax and P _{det at Qmax} were taken into consideration. Indices like Bladder Outlet Obstruction Index (BOOI) and Bladder Contractility Index (BCI) were calculated. Multivariate analysis was run to assess correlation of ABC with other parameters. Receiver Operating Characteristics (ROC) curve analysis was performed to assess predictive values of BOOI for ABC.

RESULTS

We did not find the ABC to change with age as has been classically described. Qmax and BCI were found to correlate with age. Values obtained for P _{det at Qmax} and BOOI were not dependent on age and were in similar range as observed in adults. On multivariate analysis, small bladder was found to positively correlate with presence of overactivity, high BOOI and low BCI. ROC curve analysis showed a BOOI >29 could predict ABC to be <100% EBC with moderate sensitivity and specificity.

DISCUSSION

Pressure flow studies are the only objective means of quantifying outlet resistance, hitherto they have been considered to be unrepresentative in children. Documentation and correction of high outflow pressures may arrest the cycle of detrusor hypertrophy and dysfunction.

CONCLUSION

Quality pressure flow studies are feasible in children. Values of P _{det at Qmax} and BOOI in children are age independent and similar to those observed in adults. BOOI can be potentially used in children to assess degree of BOO.

Challenges in pediatric urologic practice: a lifelong view

The role of the pediatric urologic surgeon does not end with initial reconstructive surgery. Many of the congenital anomalies encountered require multiple staged operations while others may not involve further surgery but require a life-long follow-up and often revisions. Management of most of these disorders must extend into and through adolescence before transitioning these patients to adult colleagues. The primary goal of management of all congenital uropathies is protection and/or reversal of renal insult. For posterior urethral valves, in particular, avoidance of end-stage renal failure may not be possible in severe cases due to the congenital nephropathy but usually can be prolonged. Likewise, prevention or minimization of urinary tract infections is important for overall health and eventual renal function. Attainment of urinary continence is an important goal for most with a proven positive impact on quality of life; however, measures to achieve that goal can require significant efforts for those with neuropathic bladder dysfunction, obstructive uropathies, and bladder exstrophy. A particular challenge is maximizing future self-esteem, sexual function, and reproductive potential for those with genital anomalies such as hypospadias, the bladder exstrophy epispadias complex, prune belly syndrome, and Mullerian anomalies. Few endeavors are rewarding as working with children and their families throughout childhood and adolescence to help them attain these goals, and modern advances have enhanced our ability to get them to adulthood in better physical and mental health than ever before.

Do functional changes occur in the bladder due to bladder outlet obstruction? - ICI-RS 2018

Studies on bladder dysfunction (BD), more specifically functional‐urodynamic changes in the bladder as a result of bladder outlet obstruction (BOO) have been summarized for this TT. Based on available, but limited evidence from human studies a three‐stage model can be hypothesized to characterize BOO‐induced bladder remodeling: hypertrophy, compensation (increased detrusor contractility during the voiding phase, often in combination with filling phase detrusor overactivity) followed by the phase of decompensation [detrusor underactivity]. The time between the start of compensation and eventual decompensation seems to be determined by age of onset, severity, and type of obstruction and clinical mitigating factors such as vascular and metabolic problems. Understanding the relative contributions of these factors may allow the development of personalized timelines and probabilities for these obstructed patients.

Posterior urethral valves: comparison of clinical outcomes between postnatal and antenatal cohorts

BACKGROUND

Posterior urethral valves (PUVs) constitute the most common infravesical urinary obstruction in boys and are often accompanied by severe consequences to the lower and upper urinary tract. Currently, about two-thirds of diagnosis of PUVs has been suspected by prenatal ultrasonography findings. The aim of this study was to compare long-term clinical outcomes in two groups of patients with PUVs, with antenatal vs. postnatal diagnosis.

STUDY DESIGN

This was a retrospective cohort study of 173 patients with PUVs systematically followed up in a tertiary center. Median follow-up time was 66.5 months (interquartile range [IQ], 11.4-147.9 months) for those patients who survived neonatal period. Seventy-nine (45.6%) patients were followed up for more than 5 years and 55 (32%) for more than 10 years. For analysis, the cohort was stratified into two groups according to the clinical presentation (prenatal vs. postnatal). The events of interest were urinary tract infection (UTI), surgical interventions, proteinuria, hypertension, chronic kidney disease (CKD), and death. Survival analyses were performed to evaluate time until occurrence of the events.

RESULTS

Sixty-two patients (35.8%) were diagnosed by fetal sonography. Patients of postnatal group presented a higher incidence rate of UTI episodes (6.5, 95% confidence interval [CI], 4.9-8.3) than antenatal group (1.2, 95% CI, 0.4-2.7) (P < 0.001). Thirty-six patients (21%) presented hypertension, and 77 (44.5%) had persistent mild proteinuria. There was no significant difference in the estimated incidence of hypertension (P = 0.28) and proteinuria (P = 0.78) between antenatal and postnatal groups. The cumulative incidence of CKD stage ≥3 was estimated to be about 37% at 10 years of age, and 56% at 18 years of age. By survival analysis, there was no significant difference in the estimated incidence of CKD stage ≥3 (log-rank = 0.32, P = 0.57) and CKD stage 5 (log-rank = 1.08, P = 0.28, Figure) between antenatal and postnatal groups. Of 173 patients included in the analysis, 13 (7.5%) died during follow-up with a median age of 2.6 months (IQ, 15 days-62 months). Survival analyses have not shown any significant difference in the estimated incidence of death between antenatal and postnatal groups (log-rank = 1.38, P = 0.24).

CONCLUSION

The study findings did not corroborate the initial hypothesis that the rates of renal function declining in patients with PUVs would be attenuated by an early diagnosis and intervention after antenatal diagnosis.

Efficacy of bladder neck incision on urodynamic abnormalities in patients with posterior urethral valves

PURPOSE

This study aims to study the efficacy of simultaneous endoscopic bladder neck incision (BNI) and primary endoscopic valve incision (PEVI) in patients with posterior urethral valves (PUV).

MATERIALS AND METHODS

Nine PUV patients underwent PEVI and BNI over a year. They were compared to nine comparable historical controls that had undergone only PEVI. Trends in renal function tests, urodynamics and changes in the upper urinary tracts were evaluated after 3 months during which no pharmacotherapy was given.

RESULTS

The incidence of bladder dysfunction in the two groups was similar-55.5 % in case group and 66.6 % in control group. Hypocompliant, high-pressure bladder was the predominant cystometric finding in both groups. Three patients in the case group and two patients in the control group had high end infusion pressure (EIP) with poor compliance. Detrusor overactivity (DOA) was seen in 23.1 % patients in the case group as compared to 55.5 % patients in the control group (P = 0.3348). Five patients in both groups were later started on anticholinergics due to raised EIP, small capacity bladder and/or DOA.

CONCLUSION

Although BNI should theoretically improve the outcome of PUV patients, the current pilot study failed to demonstrate any significant difference. A larger sample size and longer follow-up are required to prove or disprove its efficacy.

Long-term bladder function followup in boys with posterior urethral valves: comparison of noninvasive vs invasive urodynamic studies

PURPOSE

We studied whether noninvasive urodynamic evaluation can be as effective and safe as invasive urodynamics in detecting lower urinary tract dysfunction and in preventing late onset renal failure during long-term management of boys with posterior urethral valves.

MATERIALS AND METHODS

We evaluated 47 boys with posterior urethral valves using repeat urodynamics. A total of 28 patients with followup of at least 3 years and repeat evaluation of serum creatinine were included in the study. The first 14 boys in the series underwent cystometry and pressure-flow study at least every 3 years (group A), and the remaining 14 patients were monitored annually from age 5 with bladder diary, uroflowmetry, post-void residual urine on ultrasound and serum creatinine (group B). Lower urinary tract dysfunction and serum creatinine were compared (Fisher exact test and Mann-Whitney test) between groups A and B, and by stratifying patients into subgroups by age (5 to 6, 7 to 13 and older than 13 years). In all patients urodynamic diagnosis of lower urinary tract dysfunction was matched and confirmed with lower urinary tract symptoms.

RESULTS

During followup the prevalence of lower urinary tract dysfunction did not differ significantly between group A (71% in boys 5 to 6, 43% in boys 7 to 13 and 85% in boys older than 13 years) and group B (36%, 43% and 60%, respectively). Late onset renal failure was observed in 2 boys in group A and 2 in group B.

CONCLUSIONS

Noninvasive urodynamic evaluation seems to be as safe and effective as invasive urodynamic study in the long-term management of boys with posterior urethral valves. Based on these findings, invasive urodynamics may be reserved for cases of progressive deterioration of lower urinary tract dysfunction or renal function.

Mini-vesicostomy in the management of PUV after valve ablation

AIM

To determine the usefulness of infra-umbilical mini-vesicostomy in infants with posterior urethral valves (PUV), in developing countries. This new technique facilitates clean intermittent catheterization (CIC) and overnight bladder drainage, which have been effectively used for the treatment of valve bladders in the developed world.

METHODS

A retrospective analysis of the records of three infants who underwent a mini-vesicostomy between 2005-2009 was done. All were put on CIC in the neonatal period. Monitoring of renal parameters, bladder function and structural changes in the bladder was done before and after 4 years of CIC.

RESULTS

All three showed a decrease in upper tract dilatation, improvement in cortical function and improvement of bladder compliance at the end of 4 years. Two patients are on CIC through vesicostomy and can pass a good stream of urine per urethraly, and in one the vesicostomy has been closed.

CONCLUSION

Mini-vesicostomy is a useful option to allow CIC on a long-term basis in children with PUV. There were no complications with this technique in this small group of patients, and it has been well accepted by their families.

A review of urodynamic evaluation in children and its role in the management of boys with posterior urethral valves

Posterior urethral valves are the commonest cause of lower urinary tract outflow obstruction in male infants with an estimated incidence of 1:5000 male infants and 1:25,000 live births. Despite treatment with fulguration of the obstructing valves, bladder function is abnormal in up to 70% of older children and adolescents. Bladder dysfunction causes morbidity e.g. urinary incontinence and has been implicated in the late deterioration of renal function in this population. A poor understanding and inappropriate management of bladder dysfunction can result in unnecessary morbidity, which can handicap a child for life. Any method that measures function or dysfunction of the lower urinary tract constitutes a urodynamics investigation. Broadly, the investigations can be classified into simple or noninvasive urodynamics and invasive urodynamics. The objective of urodynamics assessments in children is to reproduce the patient's complaints or symptoms. Video urodynamics can provide additional information that may contribute to a further understanding of the problem under investigation. Urodynamics provides a useful tool to test the efficacy of treatment as well as determine any refinements necessary to improve the outcome of such treatment.

Primary ablation of posterior urethral valves in low birth weight neonates by a visually guided fogarty embolectomy catheter

PURPOSE

In low birth weight neonates primary ablation of posterior urethral valves represents a particular difficulty. The tiny caliber of the urethra presents a challenge for even the smallest commercially available pediatric resectoscope. Transurethral ablation by wired electrodes is difficult due to the narrow field of neonatal scopes with slow irrigation and restricted maneuverability. A Fogarty embolectomy catheter under fluoroscopic control does not allow direct visual assessment, and can be a lengthy procedure with numerous manipulations at the radiology suite. We describe a hybrid technique for primary valve ablation in neonates using a Fogarty catheter working retrograde under direct visual guidance of a neonatal cystoscope.

MATERIALS AND METHODS

A total of 17 low birth weight newborns (median 2,100 gm, range 1,760 to 2,690) underwent primary valve ablation using a 2Fr Fogarty catheter working through a 7.5Fr neonatal cystoscope with an offset lens. Both components were withdrawn as a single unit to avulse the valve leaflets under vision. Vesicoureteral reflux was present in 13 patients (76%) involving 24 renal units. A voiding cystourethrogram was performed 8 to 10 weeks postoperatively to delineate adequate decompression of the posterior urethra and mark the end point of the study in evaluating the efficiency of the technique.

RESULTS

There were no immediate perioperative complications. Three patients died of causes unrelated to the procedure, leaving 14 boys (21 refluxing units) for evaluation. Voiding cystourethrogram revealed effective decompression of the posterior urethra with adequate drainage in all but 1 remaining patient (93%) due to a persistent left leaflet. Of 21 refluxing units reflux resolved in 6 (29%), was downgraded in 10 (48%) and remained unchanged in 5 (24%).

CONCLUSIONS

In low birth weight neonates primary valve ablation by a visually guided Fogarty catheter ensures effective disruption of the valvular obstructive mechanism. The technique maintains the transurethral visual standard and avoids the difficult manipulation of wired electrodes in a restricted field. It is devoid of radiation exposure and its simplicity enables safe performance at the neonatal intensive care unit, where the support needs of this fragile subset of patients are optimally provided for.

The urethral valve of Guérin and lacuna magna: clinical presentations and urodynamic findings

We described the clinical presentations, radiological findings, urodynamic patterns and endoscopic management in a series of patients with symptomatic lacuna magna (LM). The medical records of 14 boys diagnosed as LM were reviewed, retrospectively. The presence of LM was first diagnosed based on clinical history, physical exam, and radiological findings; then confirmed by urethroscopy. Urodynamic study was performed in 10 boys before and after the procedure. Transurethral incision and fulguration of the valve was performed in all patients. The mean (range) age of patients was 3.1 years (6 months to 8 years). The boys presented with dysuria (n = 9), postvoid dribbling (n = 4), hematuria (n = 3), bloody spotting (n = 3), enuresis (n = 4), and glanular irritation and pain (n = 6). The post-operative period was uneventful in all patients. The symptoms were relieved and repeat radiological exam showed complete resolution of LM in all children by the 3rd post-surgical month. Before the procedure, main urodynamic abnormalities in children were high P(detmax) and detrusor instability that significantly improved within 3-6 months after treatment. Despite evidence suggesting that a LM is a frequent, normal anatomical variant, the valve may cause symptoms such as intermittent hematuria, dysuria, and bloody spotting of underwear. The lesion may be associated with obstructive urodynamic patterns in some children. Endoscopic treatment of patients effectively relieves the symptoms and corrects the urodynamic abnormalities.

Radiotelemetered urodynamics of obstructed ovine fetal bladders: correlations with ex vivo cystometry and renal histopathology

OBJECTIVE

To test the hypothesis that fetal bladder outlet obstruction (BOO) in sheep causes abnormal urodynamics correlating with the initiation of renal pathology, as most boys with posterior urethral valves (PUV) have bladder dysfunction when assessed after birth.

MATERIALS AND METHODS

Male ovine fetuses at 94 days of gestation were assigned to BOO (four) or sham control (five) groups. In BOO fetuses, radiotelemetry catheters were inserted transurachally and intraperitoneally, and the urethra was partly occluded. In two sham controls catheters were inserted directly through the bladder wall; the remaining three had sham surgery only. Radiotelemetered cystometry was recorded daily where possible. At the end of the experiment (9 days), ex vivo cystometry, bladder contractility studies and renal tract histology were assessed.

RESULTS

Ultrasonography showed dilated renal tracts only in BOO fetuses; three of four BOO fetuses had renal cortical cysts. The control fetuses with bladder catheters died in utero, so urodynamics were recorded only in fetuses with BOO. The baseline filling/storage detrusor pressures increased slightly (by a mean of 5 mmHg) during the first 4 days of BOO, thereafter returning to those at the outset. There were marked changes in the patterns of bladder activity from 1 to 9 days. The frequency and duration of 'voiding' increased; as such the higher sustained pressures of emptying activity were progressively extended and the periods of low pressure filling/storage accordingly shortened. The patterns among individual fetuses with BOO were not substantially different, except that the one with the non-cystic kidneys had a more moderate frequency and duration of voiding. Ex vivo compliance and contractility showed no consistent differences in detrusor compliance or contractility between BOO and sham bladders.

CONCLUSION

In this fetal model of PUV, there was a progressive increase in the duration and frequency of sustained elevated 'voiding' pressures, with no change in bladder compliance. Fetal kidneys were sensitive to these altered dynamics, with the formation of cortical cysts by 9 days after initiating BOO.

Does bladder augmentation stabilize serum creatinine in urethral valve disease? A series of 19 cases

OBJECTIVE

This study evaluates the results of bladder augmentation (BA) in 19 boys with posterior urethral valves, especially as regards its efficacy in stabilizing serum creatinine.

PATIENTS AND METHODS

In the period 1995-2005, 188 patients with urethral valves were surgically managed. Nineteen of these had undergone BA as a part of their surgical management after initial endoscopic valve ablation in 15 and diversion in four boys. The mean serum creatinine at the time of BA was 2.11 mg/dl.

RESULTS

BA stabilized the serum creatinine in 14 but failed to do so in five boys. A serum creatinine level of more than 2mg/dl at the time of BA was associated with a significantly worse rate of success. BA as part of an undiversion procedure in three boys was unsuccessful.

CONCLUSION

In an economic milieu where renal transplantation is not available for the majority of deserving children, careful selection is required before BA is considered as a surgical solution for the valve bladder. BA, when otherwise indicated, has been beneficial in children with pre-augmentation creatinine up to 2 mg/dl.

Urodynamic investigation of valve bladder syndrome in children

OBJECTIVE

To investigate urodynamic manifestations and their relationship with the postoperative experience of children with valve bladder syndrome (VBS).

METHODS

Included were 16 children (mean age 3.2+/-1.8 years) with VBS, who were divided into two groups. The urodynamic study was performed less than 1 year in group 1 (seven boys, aged 1-1.9 years) and more than 1 year in group 2 (nine boys, aged 2.9-6.5 years) after urethral valve fulguration; at the time of operation patients were less than 2 years old. Standards of the International Children's Continence Society were respected, and results were compared between the two groups.

RESULTS

Compared to group 1, group 2 showed a significant decrease in maximum detrusor voiding pressure (Pdet.void.max) and bladder compliance (BC), and an increase in post-voiding residual (PVR) and maximum bladder capacity (MBC) (p<0.05), but the difference in detrusor instability was not significant (p>0.05), Pdet.void.max and PVR were 56.2+/-14.1 cmH(2)O and 96.6+/-52.4 ml, respectively, in group 2, and there were more intermittent detrusor contractions during voiding in this group.

CONCLUSION

Patients with VBS frequently present with multiple bladder dysfunctions that can be diagnosed accurately using urodynamics. Even after urethral valve fulguration Pdet.void.max and BC were inclined to decrease, while PVR and MBC increased with the growth of the children.

Myogenic bladder decompensation in boys with a history of posterior urethral valves is caused by secondary bladder neck obstruction?

OBJECTIVE

To investigate whether myogenic bladder decompensation in patients treated for congenital posterior urethral valves (PUV, the most serious cause of infravesical obstruction in male neonates and infants) may be secondary to bladder neck obstruction, as despite prompt ablation of PUV these patients can have dysfunctional voiding during later childhood or adolescence, the so-called 'valve bladder syndrome'.

PATIENTS AND METHODS

The study comprised 18 boys (mean age 14 years, range 6.2-18.5) who had had successful transurethral ablation of PUV between 1982 and 1996, and had completed a follow-up which included serial assessment of serum creatinine, completion of a standard voiding diary, ultrasonography with measurement of urine before and after voiding, a urodynamic examination with simultaneous multichannel recording of pressure, volume and flow relationships during the filling and voiding phases, coupled with video-cystoscopy at least twice. The mean (range) follow-up was 9.3 (6-17) years.

RESULTS

Urodynamic investigation showed myogenic failure with inadequate bladder emptying in 10 patients; five with myogenic failure also had unstable bladder contractions. On video-cystoscopy the posterior bladder neck lip appeared elevated in all patients but in those with myogenic failure it was strongly suggestive of hypertrophy, with evidence of obstruction. At the last follow-up one patient with myogenic failure who had had bladder neck incision and four others who were being treated with alpha-adrenergic antagonists had a significant reduction of their postvoid residual urine.

CONCLUSION

Despite early valve ablation, a large proportion of boys treated for PUV have gradual detrusor decompensation, which may be caused by secondary bladder neck obstruction leading to obstructive voiding and finally detrusor failure. Surgical or pharmacological intervention to improve bladder neck obstruction may possibly avert this course, but further studies are needed to validate this hypothesis.

First report of overactive detrusor in association with hypospadias detected by urodynamic screening

AIMS

The purpose of this study was to determine urodynamic features in hypospadic patients.

METHODS

Thirty-seven patients with hypospadias (distal: 31, proximal: 6) underwent preoperative urodynamic study according to International Continence Society (ICS) recommendations. Statistical analysis were done for comparison between urethral obstruction and non-obstruction in patients with detrusor overactivity (DO) plus the relationship of DO with localization of hipospadias.

RESULTS

Nearly 45.9% of the patients showed overactive detrusor. Urethral obstruction was found in 60.8% of the patients. The rate of DO was higher in proximal hipospadias, and urethral obstruction than distal type, and non-obstructed patients (P > 0.005). The means overall cystometric capacity, maximum voiding detrusor pressure and maximal urinary flow measured were 132.6 +/- 111.14 ml (range 21-610), 72 +/- 53 cmH2O (range 12-181), and 7.9 +/- 7.1 ml/sec (range 2-30 ml/sec), respectively.

CONCLUSIONS

To the best of our knowledge, this is the first study ever to show that overactive detrusor is an accompanying entity in the hypospadic patients.

Pediatric urodynamics: baseline audit and effect on management

OBJECTIVES

To undertake a baseline audit of our pediatric urodynamic service, identifying areas for improvement, and to determine whether clinical management was affected by urodynamic results.

PATIENTS AND METHODS

All pediatric urodynamic studies during one calendar year were reviewed to determine the quality of reports that were issued and to assess any problems encountered. A postal questionnaire was sent to all referring doctors to determine whether the urodynamic report had influenced management.

RESULTS

In all, 48 children attended for videocystometry, with successful tests in 39 (81%); 97% of written reports were judged to contain adequate information. In all, 33 postal questionnaires were returned (85%); in 30 (91%) the referring clinician felt that the urodynamic result had directly influenced management.

CONCLUSION

The audit highlighted areas for improvement, which have been addressed. The response from the postal questionnaire showed that urodynamics directly influenced the management of children with complex urological and neurological abnormalities.

Does Treatment With Clean Intermittent Catheterization in Boys With Posterior Urethral Valves Affect Bladder and Renal Function?

PURPOSE

In boys with resected posterior urethral valves (PUV) deterioration of renal function is seen during childhood and adolescence, which may partly be caused by bladder dysfunction. We present data on renal and bladder function initially and at followup of boys with PUV in whom the bladder dysfunction has been treated since infancy.

MATERIALS AND METHODS

The study included 35 boys with PUV. Bladder regimen, including early toilet training from the age of 1.5 years and detrusor relaxant drugs for the treatment of incontinence from ages 4 to 6 years, was introduced to all patients. A total of 19 boys were started on clean intermittent catheterization (CIC) at a median age of 8 months due to pronounced bladder dysfunction with poor emptying, unsafe pressure levels, high grade reflux and renal impairment.

RESULTS

No serious complications of CIC have been seen during followup. Of the 19 boys 2 stopped performing CIC due to noncompliance of the parents at 1 and 3 years, respectively. Initial renal function, measured as median glomerular filtration rate (GFR) in percent of expected for age, was 60% in the CIC group and 90% in the nonCIC group. At followup at a median age of 8 years the CIC group (n = 14, 3 transplanted boys excluded) had an increase in median differential GFR (difference between followup and initial GFR) of 7% (p <0.01), which was similar increase to that of the nonCIC group. In the 2 boys who stopped performing CIC renal function deteriorated with a median differential GFR of -24%. In the CIC group detrusor instability decreased. Poor compliance was seen in 6 of the 19 boys initially and only one remained poorly compliant. In 1 of the boys who stopped performing catheterization a low compliant bladder developed. In all of the other cases bladder capacity increased more than expected for age.

CONCLUSIONS

The results suggest that treatment of bladder dysfunction in boys with PUV can counteract the deterioration in renal function seen during childhood but the number of patients in our study is limited.

Antenatal urodynamic studies in the fetal lamb: experimental protocol and preliminary results

OBJECTIVES

To set up a fetal lamb model for intrauterine fetal urodynamic studies.

METHODS

Fourteen fetal lambs underwent placement of a bladder catheter at a mean gestational age of 87 days. Three fetuses also had a partial urethral obstruction by the simultaneous placement of a peri-urethral constricting ring. Urodynamic and ultrasound studies were performed weekly by the filling cystometry method.

RESULTS

Hundred and six voiding cycles were recorded during 25 urodynamic studies between 84- and 133-days gestation. All voiding profiles were biphasic with a mean duration of 4.2 min (range 1-10), a mean voiding pressure of 23 cm of water (range 7-33) and a mean periodicity of 19.2 min (range 11-50). The obstructed animals had bladder overactivity. This correlated with ultrasound and post-mortem findings of megacystis and bilateral hydroureteronephrosis. The fetal mortality rate was 85.7% and the mean duration of survival post surgery was 45 +/- 5.7 days.

CONCLUSION

Serial urodynamic studies could be performed in a fetal lamb model. Following partial urethral obstruction, bladder overactivity was observed.

Special considerations of the overactive bladder in children

The overactive bladder (OAB) in children is defined as both involuntary detrusor contractions and urethral instability. The development of urinary control plays a key role in its incidence and in our understanding of its pathogenesis. It is seen in a number of conditions but by far is most common among patients with dysfunctional voiding. Urinary infection can be both a cause and an effect of OAB. In some instances, vesicoureteral reflux may result from detrusor overactivity because its successful resolution has been shown to depend on abolition of the hyperactivity. Early diagnosis and appropriate treatment can affect upper urinary tract function and drainage and ultimate bladder function. Recognition is noted via a thorough history and careful physical examination. Urodynamic assessment is indicated in neurologically normal children >5 years old and is combined with a voiding cystourethrogram in boys and a radionuclide cystogram in girls who have a history of recurrent urinary infection. Treatment consists of prophylactic use of anticholinergic agents in patients with neurologic dysfunction, as an early adjunctive measure in boys after ablation of posterior urethral valves, and in children with vesicoureteral reflux. The dose must be carefully titrated in children with cerebral palsy to prevent the appearance of elevated residual urine. Behavioral therapy and biofeedback techniques are effective alternatives to anticholinergic agents for children with dysfunctional voiding.

The valve bladder syndrome: pathophysiology and treatment with nocturnal bladder emptying

PURPOSE

We determine the etiology and treat the specific pathophysiology of the valve bladder syndrome.

MATERIALS AND METHODS

Defined as persisting or progressive severe hydroureteronephrosis without residual or recurrent obstruction, the valve bladder syndrome developed in 18 boys who underwent successful ablation of the posterior urethral valve. Serial radiographic, renal function, renographic, urodynamic and perfusion studies were performed for a mean time of 11 years.

RESULTS

The cause of the valve bladder syndrome proved to be sustained bladder over distention due to a combination of polyuria with 24-hour urine volume greater than 2 l. in 10 boys, impaired bladder sensation in 18 and residual urine volume in 14. Treatment of over distention during the daytime alone was unsuccessful. Nocturnal bladder emptying was performed with an indwelling nighttime catheter, intermittent nocturnal catheterization and/or frequent nocturnal double voiding. Hydronephrosis markedly improved once nocturnal bladder emptying was started and was comparable to the results after urinary diversion.

CONCLUSIONS

The valve bladder syndrome is not due to a permanent prenatal alteration in bladder anatomy and function. Instead, it appears to result from sustained postnatal bladder over distention due to a combination of polyuria, impaired bladder sensation and residual urine volume, which represent sequelae of prenatal valve injury. These factors synergize to prevent bladder normalization after valve ablation and progressively reduce functional bladder capacity to maintain bladder over distention. Bladder decompensation, upper tract dilation, and renal injury develop and characterize the valve bladder syndrome. Because current therapy, including intermittent catheterization, leaves the bladder full throughout the night, it remains markedly over distended. Nocturnal bladder emptying is the specific antidote for this pathophysiological situation, and results in prompt and impressive improvement or elimination of hydronephrosis in these and similar groups of patients. This response to nocturnal bladder emptying suggests that the bladder is not the primary cause for the valve bladder syndrome.

Detrusor hypocontractility evolution in boys with posterior urethral valves detected by pressure flow analysis

PURPOSE

We evaluated the natural evolution of detrusor voiding contractility in boys who underwent posterior urethral valve ablation using pressure flow analysis, which is a mathematical computerized analysis of pressure flow studies.

MATERIALS AND METHODS

Among 30 boys with posterior urethral valves who were being prospectively followed, even if asymptomatic on serial pressure flow studies, 11 were included in our study. These 11 patients had had at least 2 evaluations performed between ages 5 and 15 years, a minimum interval of 4 years between the first and last examination, and all pressure flow studies records available for mathematical analysis of voiding contractility. The first examination had been done at ages 5 to 10 years (average 7 +/- 2.04) and the last one at ages 9 to 15 (12.5 +/- 2.5), including 6 evaluated after puberty. All but 1 patient underwent valve endoscopic resection as a newborn and none received urinary diversion. Voiding symptoms, post-void residual, cystometric bladder capacity and bladder instability were considered. Voiding phase maximal detrusor pressure and flow rate were evaluated and detrusor contractility was calculated by the pressure flow analysis parameters of contraction velocity, detrusor contractile power expressed as watt factor and Schafer's nomogram. Contraction velocity and contractile power factor were considered low if below 2 standard deviations of previously determined normal values. True hypocontractility was diagnosed when at least 2 pressure flow analysis parameters were low.

RESULTS

True hypocontractility was detected in 3 of the 11 boys at the first examination and in 8 at the last pressure flow analysis. The remaining 8 and 3 cases of first and last examinations, respectively, were considered to have normal contractility even if 4 of the 8 and 1 of the 3 had 1 low pressure flow analysis parameter (covert hypocontractility). Detrusor contractility worsened in 6 patients, hypocontractility was detected at the first pressure flow analysis in 2, hypocontractility changed to normal in 1 and pressure flow analysis remained normal in 2. Of the 6 boys followed through puberty 5 had hypocontractility, including 3 with cystometric bladder capacity greater than 700 ml., high post-void residual and strained voiding. Of the 11 patients 8 had detrusor instability, including 7 with urge symptoms, at first evaluation which was not found at last examination.

CONCLUSIONS

Pressure flow analysis extensively used in men has been confirmed as a useful tool to assess voiding contractility in children. The majority of boys with posterior urethral valves have progressive impairment of detrusor contractility at voiding many years after relief of obstruction. The pattern of hypocontractility, which is detected early on pressure flow analysis, follows a prolonged phase of instability in many cases and leads to an over distended bladder in most patients followed after puberty. Questions arise if this evolution may be prevented by early (pharmacological or rehabilitative) treatment and if it is partially determined by extensive use of drugs acting against unstable detrusor contractions.

DETRUSOR HYPOCONTRACTILITY EVOLUTION IN BOYS WITH POSTERIOR URETHRAL VALVES DETECTED BY PRESSURE FLOW ANALYSIS

PURPOSE

We evaluated the natural evolution of detrusor voiding contractility in boys who underwent posterior urethral valve ablation using pressure flow analysis, which is a mathematical computerized analysis of pressure flow studies.

MATERIALS AND METHODS

Among 30 boys with posterior urethral valves who were being prospectively followed, even if asymptomatic on serial pressure flow studies, 11 were included in our study. These 11 patients had had at least 2 evaluations performed between ages 5 and 15 years, a minimum interval of 4 years between the first and last examination, and all pressure flow studies records available for mathematical analysis of voiding contractility. The first examination had been done at ages 5 to 10 years (average 7 +/- 2.04) and the last one at ages 9 to 15 (12.5 +/- 2.5), including 6 evaluated after puberty. All but 1 patient underwent valve endoscopic resection as a newborn and none received urinary diversion. Voiding symptoms, post-void residual, cystometric bladder capacity and bladder instability were considered. Voiding phase maximal detrusor pressure and flow rate were evaluated and detrusor contractility was calculated by the pressure flow analysis parameters of contraction velocity, detrusor contractile power expressed as watt factor and Schafer's nomogram. Contraction velocity and contractile power factor were considered low if below 2 standard deviations of previously determined normal values. True hypocontractility was diagnosed when at least 2 pressure flow analysis parameters were low.

RESULTS

True hypocontractility was detected in 3 of the 11 boys at the first examination and in 8 at the last pressure flow analysis. The remaining 8 and 3 cases of first and last examinations, respectively, were considered to have normal contractility even if 4 of the 8 and 1 of the 3 had 1 low pressure flow analysis parameter (covert hypocontractility). Detrusor contractility worsened in 6 patients, hypocontractility was detected at the first pressure flow analysis in 2, hypocontractility changed to normal in 1 and pressure flow analysis remained normal in 2. Of the 6 boys followed through puberty 5 had hypocontractility, including 3 with cystometric bladder capacity greater than 700 ml., high post-void residual and strained voiding. Of the 11 patients 8 had detrusor instability, including 7 with urge symptoms, at first evaluation which was not found at last examination.

CONCLUSIONS

Pressure flow analysis extensively used in men has been confirmed as a useful tool to assess voiding contractility in children. The majority of boys with posterior urethral valves have progressive impairment of detrusor contractility at voiding many years after relief of obstruction. The pattern of hypocontractility, which is detected early on pressure flow analysis, follows a prolonged phase of instability in many cases and leads to an over distended bladder in most patients followed after puberty. Questions arise if this evolution may be prevented by early (pharmacological or rehabilitative) treatment and if it is partially determined by extensive use of drugs acting against unstable detrusor contractions.

Posterior urethral valves: pre- and postnatal management

Posterior urethral valves are a common problem encountered by pediatric urologists. The diagnosis is most frequently suggested by antenatal screening ultrasound. A variety of pre- and postnatal parameters have been identified to aid in predicting ultimate renal outcome. These prognostic tools are invaluable to the clinician for counseling parents and for choosing appropriate management. Several approaches to the treatment of patients with posterior urethral valves exist, and the ideal strategy is debatable. As technology evolves, more options for early intervention become available. Whether early detection and antenatal intervention improve patient outcome remains to be proven.

The changing urodynamic pattern from infancy to adolescence in boys with posterior urethral valves

OBJECTIVE

To determine whether bladder dysfunction in boys with posterior urethral valves (PUV) changes from a uniform pattern of hypercontractility during infancy to the hypocontractility found in adolescence, by reviewing serial urodynamic studies.

PATIENTS AND METHODS

Thirty boys with PUV and no voiding symptoms underwent a total of 86 urodynamic tests (mean 2.8 each). The first urodynamic study was undertaken at 1-4 years of age in 15 boys and at 5-13 years in 15. They were re-evaluated at least 3 years later; 15 patients underwent the first and last urodynamic study, respectively, at a mean age of 2.8 and 7.7 years (group A), 10 boys at 6.2 and 8. 8 years (group B) and five at 9.4 and 15.2 years (group C). In 10 boys aged > 5 years the first and last pressure-flow studies (PFS) were analysed using an advanced analysis (PFA) to better identify hypocontractility.

RESULTS

Bladder dysfunction was found in 21 of 30 (70%) boys at the first evaluation and in 18 (60%) at the last. In 25 boys the urodynamic pattern changed. Of the 15 boys in group A, 10 of 12 who had hypercontractility changed to normal (seven), low compliance (one) or hypocontractility (two), and two remained stable; two of the remaining three with normal urodynamic studies changed to hypocontractility, while one was unchanged. Among the 10 boys in group B, six with hypercontractility changed to normal (three) or hypocontractility (three); two with normal urodynamic findings and one with low compliance changed to hypocontractility. Of the five boys in group C who showed severe hypocontractility after puberty, three had a normal pattern, one low compliance and one hypercontractility before puberty. The PFA showed a 'weak' detrusor in four of the seven boys who were considered normal on standard PFS. At the urodynamic follow-up, the PFA pattern changed to a 'weak' detrusor in four boys who had a normal (two) or strong (two) detrusor at the first evaluation.

CONCLUSIONS

Bladder dysfunction in boys with PUV changes during childhood and through adolescence. The urodynamic pattern of hypercontractility generally found soon after valve ablation gradually changes to hypocontractility in many boys and this pattern seems to be the rule after puberty. The evidence from this series supports the hypothesis that long-term detrusor hyperactivity in boys with PUV leads to detrusor failure, but a longitudinal 15-year follow-up from birth to puberty is needed to validate this concept.

[Posterior urethral valve: determining factors of long-term results]

Posterior urethral valves (PUV) is the most common congenital urine flow impairment in boys. Long-term prognosis involves: renal function impaired in 30 to 50% of PUV and leading to hyperdiuresis, low GFR and acidosis; bladder urodynamics impaired in 75% of PUV with abnormal urine storage, abnormal micturition and vesicoureteric reflux. Incontinence and recurrent urinary tract infections commonly reflect bladder and renal failures; abnormal bladder outlet leads to incontinence and abnormal ejaculation. The roles of antenatal treatments (vesico-amniotic shunts), neonatal treatments (resuscitation and endoscopic treatment of PUV) and long-term treatments (urinary diversions, bladder augmentation, alpha blockers, anticholinergic, dialysis and renal transplant) in the long-term outcomes of PUV are reviewed.