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Posterior urethral valves, pressure pop-offs and bladder function
M Kaefer1, M A Keating, M C Adams
1Division of Pediatric Urology, James Whitcomb Riley Hospital for Children, Indianapolis, Indiana 46202, USA.
Insights
Pressure pop-offs in boys with posterior urethral valves are linked to better bladder function. These protective mechanisms significantly improve outcomes, indicating a favorable prognosis for bladder development.
Area of Science:
- Pediatric Urology
- Developmental Urology
- Nephrology
Background:
- Posterior urethral valves (PUVs) can impact renal function due to elevated bladder pressures.
- The effect of pressure pop-off mechanisms on bladder development and function in boys with PUVs is not well-defined.
Purpose of the Study:
- To investigate the significance of pressure pop-offs for bladder function in boys with posterior urethral valves.
- To determine if pressure pop-offs are associated with favorable or unfavorable bladder outcomes.
Main Methods:
- Retrospective review of medical records for 63 boys diagnosed with posterior urethral valves.
- Analysis of bladder outcomes based on urodynamic parameters and clinical status.
- Correlation of pressure pop-off presence and number with bladder outcome.
Main Results:
- Of 55 evaluable boys, 39 (71%) had at least one pressure pop-off.
- A statistically significant positive correlation was observed between pressure pop-offs and favorable bladder outcomes (87% vs. 55%).
- Boys without pop-offs had a higher incidence of requiring augmentation cystoplasty (5 out of 7).
Conclusions:
- The presence of pressure pop-offs is a favorable prognostic indicator for ultimate bladder function in boys with PUVs.
- Pressure pop-offs appear to protect the developing bladder from adverse effects of elevated pressures.
- These findings highlight the importance of identifying pop-off mechanisms in managing PUV patients.
Abstract:
The pop-off mechanisms that sometimes occur with posterior urethral valves have well recognized implications for renal function, such that 1 or both kidneys can be protected from the deleterious effects of elevated bladder pressures. What has not been defined is the significance, if any, of pressure pop-offs to the developing bladder and ultimate bladder function. To answer this question we reviewed the records of 63 boys with posterior urethral valves. Eight boys who were not yet toilet trained had unevaluable bladder outcomes. Of the 55 remaining boys there was 1 or more pressure pop-off in 39 (71%), including massive (grade 5) reflux, massive reflux associated with ipsilateral renal dysplasia, a patent urachus, large diverticula and urinomas. Bladder outcomes were judged as favorable or unfavorable on the basis of urodynamic parameters and/or patient clinical status. A statistically significant positive correlation was found between the presence of a pop-off and a favorable outcome. Favorable characteristics were found in 34 of 39 bladders (87%) with pressure pop-offs. In contrast, only 9 of 16 bladders (55%) without pressure vents had favorable outcomes. In addition, 5 of the remaining 7 boys without pressure vents have required augmentation cystoplasty. A direct correlation between absolute number of pop-offs and favorable bladder outcome was also noted, further emphasizing this relationship. The presence of a pressure pop-off is a favorable prognostic sign for ultimate bladder function in boys with posterior urethral valves.