A comparison of bioelectrical and mechanical activity of the female urethra.

OBJECTIVE

To determine the relationship between mechanical function and innervation of the urethra in order to clarify the effect of denervation and reinnervation on urethral function.

DESIGN

Prospective observational study.

SETTING

Tertiary referral urodynamics unit.

SUBJECTS

Thirty-six women, 21 with urinary symptoms and urodynamically proven genuine stress incontinence and 15 without urinary symptoms.

INTERVENTIONS

All women underwent concentric needle electromyography of the urethral sphincter and urethral pressure profilometry at rest and during cough induced stress.

RESULTS

Significant correlations were found between variables indicating denervation and reinnervation and improved resting urethral function. No correlation was found between these variables and urethral function under stress.

CONCLUSIONS

Our findings contradict current opinion that denervation of the urethral sphincter is associated with a reduction in the sphincteric function of the urethra, at rest or during stress, and suggest that denervation cannot therefore be a major aetiological factor in the development of genuine stress incontinence.