PRESSURE CROSS-SECTIONAL AREA RELATIONS IN THE PROXIMAL URETHRA OF HEALTHY-MALES .1. ELASTANCE AND ESTIMATED PRESSURE IN THE UNINSTRUMENTEDURETHRA

The pressure/cross-sectional area relation in the resting urethra duri ng the storage phase was studied in 31 healthy male volunteers aged 23 -85 years. Measurements were performed at 5-mm intervals from the blad der neck and beyond the region of high pressure, and the elastance and estimated pressure in the uninstrumented urethra (P-0) were calculate d at each measurement location. Ah subjects were further evaluated by means of symptom score, prostatic volume determined by rectal ultrasou nd, urethral pressure profile, cystometry, and pressure flow. The elas tance and P-0 both varied along the urethra, with significantly higher values of both parameters in the sphincteric region as compared to th e prostatic area. A significant positive correlation was found between P-0 and age in the prostatic parts of the urethra, whereas no correla tion could be demonstrated between elastance and age in any part of th e urethra. These results indicate that the prostatic parts of the uret hra are readily distensible at modest intraluminal pressures as compar ed to the sphincteric segment, and that the intraluminal pressure requ ired to obtain a given distension of this segment of the urethra seems to increase with age. It is suggested that the technique may prove of value in the elucidation of pathophysiological mechanisms related to benign prostatic hyperplasia, and that the technique may bring new ins ight into the mode of action of various treatment modalities for this disease.