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.