Purpose: The urethral resistance relation was studied in relation to stress incontinence and detrusor instability, and used to examine age related differences in women.
Materials and methods: We investigated women with lower urinary tract symptoms and analyzed pressure-flow plot data.
Results: Women with pure detrusor instability had greater detrusor pressures at urethral opening and closure than those with a stable bladder and no stress incontinence. The latter women had greater detrusor opening and closing pressures than those with a stable bladder and genuine stress incontinence at all ages. Detrusor pressures at urethral opening and closure were less in absolute terms in association with greater age. Urethral resistance was lower during voiding in women with stress incontinence.
Conclusions: Our analysis showed a distinct difference in detrusor pressures at urethral opening and closure between women with and without stress incontinence. Differences were also demonstrated between women with and without detrusor instability. We found lower values of these indirect measures of urethral function in association with greater age. There was no evidence of lower urethral compliance in older women with lower urinary tract symptoms.