Posterior urethral valves--new concepts

Renal impairment in children with posterior urethral valves

BACKGROUND

Posterior urethral valves (PUV) are a common cause of end-stage renal failure in childhood. Our aim was to describe a cohort of patients with PUV and to investigate the predictors of renal impairment.

METHODS

We performed a retrospective chart review of children with PUV who were followed at King Abdulaziz University hospital between 2002 and 2011.

RESULTS

The cohort comprised 68 boys. There was a significant difference in the duration of follow-up (p = 0.024), nadir serum creatinine (p < 0.001), and last known serum creatinine level (p = 0.001) between the patients with and without renal impairment. The duration of follow-up appeared to be a significant predictor for serum creatinine doubling (p = 0.003; odds ratio, 1.8). There was no difference in the age of presentation, age at the time of the study, and first or last serum creatinine between children who initially had vesicostomy and children who had ablation.

CONCLUSIONS

Ablation of PUV or vesicostomy did not influence kidney function in our study cohort. Children with a normal nadir serum creatinine who presented early had a better outcome.

Role of alpha adrenergic blocker in the management of posterior urethral valves

PURPOSE

To evaluate the effect of Terazosin (alpha1 adrenergic blocker) on bladder emptying in children with posterior urethral valves.

MATERIALS AND METHODS

Forty-two children with significant post void residual urine after valves ablation were placed on Terazosin ranging from 0.25 to 2 mg. Post void urine at the commencement and at follow up was monitored with abdominal ultrasound.

RESULTS

Post void residual urine significantly reduced in 40 patients (95%) who were put on Terazosin. Mean pretreatment PVR was 15.7 ml and mean PVR at the last follow up was 2.4 ml (P = 0.000). This was a reduction of 85% in the pretreatment post void residual urine volume. All the patients had improvement in urinary stream. One patient reacted to Terazosin with hypotension necessitating its withdrawal. Mean follow up was 17 months.

CONCLUSION

Terazosin has proved to be safe and results in significant improvement in bladder emptying in our patients with posterior urethral valves. Randomized controlled trial and long-term follow up are necessary to further define the role of alpha1 adrenergic blocker therapy in children with posterior urethral valves. This study will become the justification for such a study.

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.

Defunctionalized bladders: effects before and after refunctionalization in an animal model

PURPOSE

Bladder behavior after refunctionalization is usually unpredictable. We comparatively analyze various aspects of bladder defunctionalization and subsequent refunctionalization using an animal model.

MATERIALS AND METHODS

A total of 18 rabbits were divided equally into 3 groups. Animals in group 1 underwent 2 successive surgical procedures, including bladder division and reattachment. Bladder division was performed by hemisecting the bladder from dome to trigone into a functioning and nonfunctioning chamber. Bladder reattachment was achieved by reanastomosing both hemibladders. Group 2 animals underwent sham operations, and group 3 animals were age matched normal controls. Serial urodynamic studies and fluoroscopic cystograms were performed in all animals. Gross, histochemical (hematoxylin and eosin, Masson's trichrome and Sirius red) and immunocytochemical (alpha-actin, collagen I and III) analyses, collagen content determination and organ bath studies were performed.

RESULTS

The defunctionalized hemibladders demonstrated lower wet weight, capacity and compliance compared to the functional contralateral and normal control bladders. Refunctionalization of the bladders resulted in a progressive recovery of capacity and compliance with time. The bladder contractile response and connective tissue-to-muscle ratio were abnormal in the defunctionalized segments but normalized after bladder refunctionalization.

CONCLUSIONS

Defunctionalization results in remarkable alterations in bladder growth, capacity, compliance and distribution of connective tissue. However, these bladders demonstrate an innate capacity to recover from these alterations following refunctionalization.