Related Experiment Videos
Posterior urethral valves after infancy-urodynamic consequences
1Division of Paediatric Surgery, Department of Surgery, University College of Medical Sciences & Guru Teg Bahadur Hospital, Delhi 110 095, India.
Insights
Late-presenting posterior urethral valves (PUV) can cause upper tract damage due to high bladder pressures. Some patients with PUV escape upper tract damage due to normal bladder dynamics, irrespective of obstruction severity.
Area of Science:
- Pediatric Urology
- Nephrology
- Pediatric Surgery
Background:
- Posterior urethral valves (PUV) are a common cause of bladder outlet obstruction in male infants.
- Late presentation of PUV beyond infancy is less common but can lead to significant urinary tract complications.
- Understanding factors influencing upper tract damage in late-presenting PUV is crucial for management.
Purpose of the Study:
- To identify factors contributing to persistent upper tract back-pressure effects despite adequate valve ablation in children with late-presenting PUV.
- To investigate factors preserving upper tracts in some patients with untreated obstruction.
Main Methods:
- Evaluation of six children with PUV diagnosed after infancy.
- Pre-operative assessment including renal biochemistry, ultrasonography, voiding cystourethrography, and uroflowmetry.
- Post-operative urodynamic studies (uroflowmetry, slow-fill cystometry) 6 months after valve ablation, confirmed by urethroscopy.
Main Results:
- Three patients with normal upper tracts showed improved flow rates and normal bladder pressures post-surgery.
- Three patients had bilateral hydroureteronephrosis, two with chronic renal failure, exhibiting decreased bladder capacity, poor compliance, and significant residual volumes.
- These findings suggest myogenic detrusor failure in patients with persistent upper tract damage.
Conclusions:
- Late-presenting PUV (beyond 5 years) can lead to upper tract deterioration associated with high bladder storage pressures.
- Some boys with long-standing PUV obstruction may maintain normal upper tracts, linked to normal bladder dynamics unrelated to obstruction severity or duration.
Abstract:
This study describes a subset of patients with posterior urethral valves (PUV) who presented late in childhood. The objective was to identify factors that lead to back-pressure effects on the upper tracts, which persist in spite of adequate valve ablation in some patients, and seek factors that may preserve the upper tracts despite untreated obstruction in other patients. Six children with PUV diagnosed after infancy were evaluated. The pre-operative work-up included renal biochemistry, ultrasonography, voiding cystourethrography, and uroflowmetry. Detailed urodynamic studies, including uroflowmetry and slow-fill cystometry, were performed in all cases 6 months after surgery. Adequacy of valve fulguration was confirmed by urethroscopy. Three of the six patients had normal upper tracts; in these, there was marked improvement in peak urine flow rates after fulguration and bladder pressures were normal. The other three patients had bilateral hydroureteronephrosis, and two had chronic renal failure. This group had markedly decreased functional bladder capacity with loss of compliance at low bladder volumes and significant residual urine volumes in spite of adequate valve fulguration, suggesting myogenic detrusor failure. We conclude that in patients with PUV presenting beyond the age of 5 years, upper-tract deterioration may accompany high storage pressures in the bladder. In some boys with long-standing obstruction the upper tracts may escape damage; in our series this was associated with normal bladder dynamics and appeared unrelated to the severity or duration of outflow obstruction.