Measurement of detrusor contractility in patients of benign prostatic hypertrophy with episodes of acute urinary retestion

Lee, Jeong Gu; Cho, Jae Heung; Koh, Sung Kun

Abstract

Incomplete bladder emptying even after prostatectomy were not uncommonly anticipated in patients with benign prostate hypertrophy (BPH) who had episodes of acute urinary retention. This may be related h impaired contractility of detrusor muscle secondary to decreased blood flow to the bladder and over-stretching of detrusor muscle caused by overdistension of bladder. We measured detrusor contractility in 41 patients with BPH who had episodes of urine retention (Group A) and 77 patients with BPH without urine retention. Also, follow up uroflowmetry were taken for 25 patients of group A and 40 patients of group B in 30-50 days after prostatectomy. Results were as follows; I. On filling cystometry. first sense of fill, urge sense to void, maximum cystometric capacity and compliance were not significantly different between 2 groups and detrusor instability were 23 cases (56%) in group A, 38 cases (49%) in group B. 2. On pressure-flow study, maximum detrusor voiding pressure was 32.5+/-4.13 cmH2O in group A and 50.27+/-2.4 cmH2O in group B (P<0.01). Peak flow rate (Qmax) and voided volume were 4.1 to 0.7 ml/sec, 76.1+/-12.7 ml in group A and 8.6+/-0.65 ml/sec, 176.1+/-16.7 ml in group B respectively (P<0.01, P<0.01). Residual urine was 256.5 1:24.3 ml in group A and 111.6 t 14.7 ml in group B (P<0.01). 3. On postoperative follow up uroflowmetry, voided volume and Qmax were increased compared to preoperative value in group A but still lower than those in group B (P<0.05, P<0.05). 4. The number of patients who didn't show any improvement of voiding symptoms after surgery were 17 on group A and 11 on group B. Impaired detrusor contractility was present in 25 of 41 cases (61%) of group A and 10 of 71 cases (13%) of group B on urodynamic diagnosis. Conclusively, in patients with BPH who had episodes of urine retention, preoperative pressure-flow study to recognize impaired detrusor contractility would be helpful in anticipating incomplete bladder emptying after prostate surgery and considering other forms of ancillary therapy.