The unstable bladder and prostatectomy.

Cystometry was carried out on 51 male patients presenting with frequency, urgency and a poor urinary stream. Twenty-four obstructed and unstable patients were referred for prostatectomy and underwent repeat cystometry at intervals after the operation. Forty-one per cent of patients became stable by 6 months and no patient reverted to stability after this time. Grading of pre-operative instability according to the provoking stimulus was of value in forecasting improvement. A voiding pressure of over 100 cm of water before operation was associated with a good result.