Evaluation and Management of Urinary Incontinence After Surgery for Posterior Urethral Valves

Best practice in the assessment of bladder function in infants

The purpose of this article is to review normal developmental bladder physiology in infants and bladder dysfunction in conditions such as neurogenic bladder, posterior urethral valves and high grade vesicoureteric reflux. We contrast the classical concept that bladder function in nontoilet-trained children is thought to be 'reflexive' or 'uninhibited', with the results of more recent research showing that infants most commonly have a stable detrusor. The infant bladder is physiologically distinct from the state seen in older children or adults. The voiding pattern of the infant is characterized by an interrupted voiding stream due to lack of proper urinary sphincter relaxation during voiding. This is called physiologic detrusor sphincter dyscoordination and is different from the pathologic 'detrusor sphincter dyssynergy' seen in patients with neurogenic bladder. Urodynamic abnormalities in neonates born with spina bifida are common and depend on the level and severity of the spinal cord malformation. Upper neuron lesions most commonly lead to an overactive bladder with or without detrusor sphincter dyssynergy while a lower neuron lesion is associated with an acontractile detrusor with possible denervation of the external urinary sphincter. In infants with neurogenic bladder, the role of 'early prophylactic treatment (clean intermittent catheterization and anticholinergics)' versus initial 'watchful waiting and treatment as needed' is still controversial and needs more research. Many urodynamic-based interventions have been suggested in patients with posterior urethral valves and are currently under scrutiny, but their impact on the long-term outcome of the upper and lower urinary tract is still unknown. Cumulative data suggest that there is no benefit to early intervention regarding bladder function in infants with high-grade vesicoureteric reflux.

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.

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.

Oxybutynin for diagnosis of infravesical obstruction in boys with urinary incontinence

OBJECTIVES

To investigate whether good suppression of symptoms during anticholinergic therapy in boys with urinary urge incontinence is correlated with anatomic infravesical obstruction.

METHODS

In a prospective study, 65 boys with urge incontinence were treated temporarily with anticholinergics. The effect of therapy was assessed, and a full video-urodynamic evaluation was performed. When obstruction could not be excluded urodynamically, urethrocystoscopy was done to assess the level and severity of obstruction, followed by endoscopic treatment. The effect of oxybutynin on incontinence was compared with the presence or absence of obstruction.

RESULTS

In 49 of 65 boys aged 4 to 14 years with daytime urge incontinence, infravesical obstruction was found. Of the 49 boys, 38 (76%) had a good response to anticholinergic therapy. Of the 16 boys without infravesical obstruction, 12 (75%) did not improve with anticholinergic therapy. When anticholinergic therapy was used as a diagnostic test for infravesical obstruction, we found a positive predictive value and negative predictive value of 90% (95% confidence interval 74% to 96%) and 52% (95% confidence interval 31% to 73%), respectively.

CONCLUSIONS

The effect of anticholinergic therapy on urge incontinence can be used as a diagnostic test to differentiate between anatomic infravesical obstruction and other causes of incontinence in boys.

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.

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.

Evolution of urodynamic patterns in posterior urethral valves

A retrospective, long-term urodynamic study was performed in order to follow the evolution of the urodynamic patterns in 55 unselected patients previously affected by posterior urethral valves (PUV). The mean maximum cystometric capacity (MCC) values progressively increased over time and, on long-term follow-up, were just above 2 standard deviations (SD). The mean compliance values were clearly reduced in the first urodynamic studies after valve ablation, and only after a mean of 5 years follow-up did they approach the lower limits of normal. The small compliance and capacity (SCC) group showed two trends of evolution: a more numerous subgroup tended toward progressive normalization while a second subgroup (<20%) showed mean compliance values below normal limits, with reduced (-2 SD) MCC persisting at long-term follow-up. The number of patients in this group decreased over time. In contrast, we were able to show a significant increase in patients with myogenic failure. In this group scheduled voiding using the Valsava maneuver in conjunction with a regimen of double or triple micturition was usually succesful in modifying the course, normalizing MCC, reducing residual urine, and also eliminating incontinence. Finally, initial urodynamic investigations in the fulguration and vesicostomy groups showed a much higher percentage of SCC bladders in the latter group (83.5% vs. 35%). However, at long-term examinations the urodynamic parameters were nearly identical in both groups, showing that temporary bladder defunctionalization does bot adversely affect future detrusor activity. No direct relationship between urodynamic abnormalities and renal insufficiency could be shown, however, the majority of patients with reduced glomerular filtration rates still showed urodynamic dysfunction at long-term follow-up. In the authors' opinion, serial urodynamic investigations in association with serial evaluation of the evolution of upper urinary tract and renal function are mandatory for correct PUV management and provide useful guidelines for avoiding incorrect treatment and obtaining better long-term results.

Congenital bladder obstruction: research strategies and directions

The clinical significance of congenital bladder obstruction is evident to those who deal with children suffering from severe bladder dysfunction and renal failure. It is a lifelong effect often requiring complex surgical reconstruction and renal transplantation. CBO also represents an important pathophysiologic process with relevance to other organ systems in which hypertrophic and fibrotic processes occur. CBO occurs in a dynamic and developing organ in which function and development are interdependent. Alterations of one will induce alterations in the other which then affect the first. Multiple levels of organization are involved and relevant, from the cell to the whole bladder as a part of the organism. Functional and developmental changes have been demonstrated in models of CBO. Much attention has been focused on the connective tissue compartment of the bladder due to its important role in determining bladder compliance characteristics. Preliminary findings suggest that connective tissue remodeling may be affected by alterations in the balance of the regulatory mechanisms of collagen degradation. Further studies should be able to define these alterations and may permit specific modulation of these mechanisms.

A fetal lamb model of partial urethral obstruction: experimental protocol and results

The functional effects of bladder outlet obstruction in the developing urinary tract are well recognized in patients born with posterior urethral valves, in whom a spectrum of bladder dysfunction has been described. To better understand the changes occurring in the partially obstructed developing lower urinary tract, a fetal lamb model of partial urethral obstruction was developed. Fetal lambs at 90 days' gestation underwent surgical placement of a silver ring (ex utero) at the level of the proximal bladder neck, with concomitant ligation of the urachus. Control animals underwent urethral ligation only. The lambs were then allowed to go through normal gestation, and ewes were delivered spontaneously. The animals were studied between 2 and 7 days after birth. The postmortem examination showed that the ring was just distal to the bladder neck, around the proximal urethra. This resulted in gradual, partial occlusion of the urethra. Bladder weights, bladder wall thickness, and bladder capacity were significantly increased in the partially obstructed animals as compared with the controls. There was little or no upper tract dilatation in the obstructed group. This animal model, the first to produce gradual outflow obstruction in the fetus, provides a reproducible model of partial urethral obstruction. The model can be used to assay the biochemical and physiological changes found in the developing urinary tract of fetal lambs submitted to intravesical obstruction.

Developmental alterations in the fetal lamb bladder subjected to partial urethral obstruction in utero

To identify the structural changes seen in the developing bladder subjected to outflow obstruction, a fetal lamb model was developed. With this model, which attempts to reproduce conditions such as those found in posterior urethral valves, quantitative biochemical parameters were used to evaluate the effects of partial outflow obstruction on detrusor cellularity and innervation in the developing bladder. Partial urethral obstruction was created in 9 fetal sheep (90 to 100 days gestation), 6 sham operated animals serving as controls. Fetuses were delivered at term and sacrificed. Bladders were removed and weighed. Mucosa free detrusor was assayed for DNA and choline acetyltransferase (ChAT) activity, indices of cell number and cholinergic innervation, respectively. In similar specimens of detrusor, cell ploidy and nuclear size were determined by flow cytometry and nuclear morphometry, respectively. The results showed that partial urethral obstruction in utero resulted in a significant increase in bladder weight (p < 0.05) and total detrusor DNA content (p < 0.01). With the increase in detrusor DNA content, there was a parallel increase in total detrusor ChAT activity. These results suggest that early development of the bladder is altered both on a cellular level (increase in cellularity) and a neural level (increase in cholinergic nerve density) under conditions of mechanical distension.