Urodynamic assessment of patients with acute urinary retention: is treatment failure after prostatectomy predictable?

Some patients with acute urinary retention due to benign prostatic hyperplasia do not have successful outcome after prostatectomy and require either a chronic indwelling urethral catheter or clean intermittent catheterization. Urodynamic and clinical parameters were examined preoperatively in 81 men 56 to 93 years old (mean age 72 years) in search of an outcome predictor after prostatectomy.

International Prostate Symptom Score, prostate volume, retention episodes, retention volume and urodynamic parameters from a multichannel pressure-flow study were analyzed preoperatively and postoperatively. All patients underwent transurethral prostatectomy and were reexamined 2, 4, 12 and 24 weeks after surgery. A multichannel pressure-flow study was performed preoperatively and 12 weeks postoperatively.

At 24 weeks postoperatively 11 patients (13%) were unable to void and therefore classified as treatment failures while the remaining patients voided spontaneously and were classified as treatment successes. There were statistically significant differences (p < 0.005) between treatment failure and treatment success regarding age (83.5 +/- 7 versus 70.1 +/- 8 years), preoperative volume of retention (1,780 versus 1,080 ml.), and maximal detrusor pressure (24.4 versus 73.5 cm. water), but not to International Prostate Symptom Score, episodes of retention and prostate volume. The ability to void during preoperative pressure flow study and the presence of detrusor instability predicted good outcome. In treatment success patients postoperative urodynamic data showed significant decrease in detrusor pressure at maximum flow rate (from 80.8 +/- 33 to 34.6 +/- 10 cm. water). Those with treatment failure had an increase in maximal detrusor pressure (from 26 +/- 12 to 42.6 +/- 13 cm. water), suggesting detrusor recovery.

Patients with acute urinary retention, age 80 years or older, with retention volume greater than 1,500 ml., no evidence of instability and maximal detrusor pressure less than 28 cm. water are at high risk of treatment failure. However, despite treatment failure the detrusor may recover in patients younger than 80. Therefore, prostatectomy should still be performed in this group (less than 80 years old) even if preoperative urodynamics suggest an unfavorable outcome.