Urodynamic interpretation of changing bladder function and voiding pattern after radical prostatectomy: a long-term follow-up

OBJECTIVE To investigate and compare changes in the bladder function after radical prostatectomy (RP) and to correlate changes in subjective voiding symptoms with the observed changes in function. PATIENTS AND METHODS In 72 patients who had RP between 2003 and 2004, we serially evaluated urodynamic studies (UDS) before RP and at 3, 6 and 36 months afterward. The short-form International Continence Society-male symptom questionnaire was also repeated at corresponding periods. Changes in bladder contraction and storage function after RP were compared for changes in subjective symptoms. RESULTS On serial UDS, there were reductions in maximum cystometric capacity, maximum detrusor pressure and maximum urethral closure pressure (MUCP) at 3 months, after which all remained relatively unchanged. On the questionnaire, the voiding symptom domain score improved (8.04 to 4.82, P < 0.001) while the storage domain score significantly and progressively worsened, beginning from 3 months (2.25 to 3.78, P = 0.04), resulting in an unchanged overall urinary symptom-related quality of life at 3 years. The incidence of detrusor overactivity increased from 37.5% before RP, to 45.8% at 3 months and 51.4% at 3 years. At 3 years, a recurring postvoid residual urine volume was the cause of the deterioration in the voiding symptom domain score, while a prominent reduction in MUCP resulted in a deterioration in the storage symptom score. CONCLUSIONS There is a reduction in bladder capacity, detrusor and sphincteric activity immediately after RP, stabilizing thereafter but remaining significantly reduced at 3 years. Although voiding symptoms improved in most men, the significant deterioration in storage symptoms, which might be attributed to sphincteric incompetence in addition to increased detrusor overactivity, became a source of overall urinary bother in the long term.