Urodynamic findings in chronic retention of urine and their relevance to results of surgery.

Fifty-five consecutive male patients aged 18-77 with chronic retention of urine were investigated urodynamically. All were shown to have obstructed micturition. Inflow cystometry defined two groups, one with high-pressure and one with low-pressure filling. Recent-onset enuresis and upper-tract dilatation as seen on radiography were significantly associated with high-pressure bladder filling. Postoperative studies showed that patients with high-pressure filling on preoperative cystometryhad a better response to outflow-tract surgery. The poor response of the patients with low-pressure filling was due to a high incidence of inadequate detrusor contraction leading to persistent residual urine. Thus urodynamic studies may be used to indicate which patients are likely to benefit from prostatectomy and, after the operation, whether the obstruction has been relieved.