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J Urol. 2001 Jul;166(1):166-70; discussion 170-1.

Transurethral prostatic resection or laser therapy for men with acute urinary retention: the ClasP randomized trial.

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  • 1Department of Social Medicine, University of Bristol, United Kingdom.



Transurethral resection of the prostate is the standard operation for acute urinary retention, although laser prostatectomy is reportedly effective and safe. The ClasP (conservative management, laser, transurethral resection of the prostate) study compared transurethral prostatic resection and noncontact neodymium (Nd):YAG visual laser assisted prostatectomy for treatment of acute urinary retention.


This study was a multicenter randomized controlled trial, analyses were by intention to treat and followup was at 7.5 months after randomization. Primary outcomes were treatment failure, and included International Prostate Symptom Score, International Prostate Symptom Score quality of life score, residual urine and flow rate. Secondary outcomes included complications, and duration of catheterization and hospitalization.


A total of 148 men were randomized to transurethral prostatic resection (74) and laser (74). There were fewer treatment failures after prostatic resection (p = 0.008) and fewer men after resection required secondary surgery for poor results (1 versus 7, p = 0.029). Maximum flow rates after transurethral prostatic resection were better than after laser (mean difference 4.4 ml. per second). Comparison of symptom and quality of life scores demonstrated that any clinically significant advantage for laser could be ruled out. Patients stayed a mean of 2 extra days in the hospital after resection. The duration of catheterization was greater after laser but significantly fewer major treatment complications were found with laser therapy.


Transurethral prostatic resection was more effective, resulted in fewer failures than laser treatment and remains the procedure of choice for men with acute urinary retention.

[PubMed - indexed for MEDLINE]
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