Conventional and extramural ambulatory urodynamic testing of the lower urinary tract in female volunteers

Referential quantitative urodynamic parameters obtained in healthy subjects can rarely be found in the literature. More differentiated and reliable urodynamic diagnoses are essential, since our patient groups and the available therapies are more diverse. Therefore, a group of 50 healthy female volunteers was investigated urodynamically. After a standardized questionnaire 14 volunteers were excluded: 12 because of lower urinary tract symptoms and 2 because of failure of equipment. Conventional and ambulatory techniques were applied. Results of the conventional method were compared with the literature: in 18% of the subjects detrusor instability was noted. During ambulatory monitoring this incidence was 69%. The mean detrusor activity index is introduced. This index contains the number of detrusor contractions in the absence of voiding per hour, the mean amplitude of these contractions and the mean duration. In volunteers and patients with stress incontinence the mean detrusor activity index was significantly lower compared to patients with complaints of urge and/or urge incontinence. As expected, transmission ratios were lower in the distal urethra. At filling volumes of approximately 100 (first sensation) and 300 (strong desire) ml. a decrease in the transmission ratio was noted.