Preoperative cystometrography in patients with clinical benign prostatic hypertrophy

Summary

Preoperative water cystometrograms obtained from 437 patients with benign prostatic hyperplasia (BPH) were examined in a retrospective study. The cystometrographic results were analyzed regarding the preoperative clinical features: the patients' age, presence or absence of urinary incontinence, history of urinary retention, and rate of residual urine. Their prognostic value in terms of improvement in voiding difficulty and postoperative urinary incontinence was also analyzed at 1 and 6 months after elective transurethral resection of the prostate (TURP). Of these patients, 263 (60.2%) had detrusor instability (group I), whereas 174 did not (group II). Vesical denervation supersensitivity (Vds) to bethanecol chloride was noted in 47 (12.5%) of 375 patients. The observed difference in clinical features was significant between the two groups, with group I being older (P<0.01) and showing a greater incidence of urinary incontinence (P<0.001) and retention (P<0.001). The difference seen between groups I and II in terms of mean bladder capacity (P<0.01), compliance (P<0.01), and a greater positive rate of Vds (P<0.001) was also significant. The clinical and cystometrographic parameters studied worsened with advancing age of the patients. Although the majority of the patients (94.7%) were relieved of obstructive symptoms after TURP (6 months later), 113 (25.9%) showed no relief at 1 month. As compared with the 324 early improvers (74.1%), nonimprovers at 1 month were characterized by a higher age (P<0.01), a higher prevalence of preoperative incontinence (P<0.05) and retention (P<0.01), a higher residual urine rate (P<0.05), a less compliant bladder (P<0.01), and a higher positive rate of Vds (P<0.05). The cystometrographic findings, however, had no relevance to the late (6 months) outcome of voiding difficulty. On the other hand, postoperative incontinence was noted in 100 patients (22.9%) at 1 month after TURP, the majority of whom were afflicted with similar preoperative episodes (70.0%) and detrusor instability (87.0%). They were also older (P<0.01) and had a less compliant bladder (P < 0.01) and a higher positive rate of Vds (P<0.01) than did continent patients. Only 18 elderly patients (4.1%), however, remained incontinent 6 months later, all of whom initially had a less compliant (P<0.01) and more unstable bladder (P<0.01). The genesis of this detrusor dysfunction was conjectured to be a function of aging in men whereby BPH evolves and progresses. In conclusion, preoperative cystometrography in patients with BPH is valuable in that (1) it correlates well with the clinical features and (2) it can predict to some extent the outcome of obstructive symptoms and urinary incontinence after TURP.