A comparison of bioelectrical and mechanical activity of the female urethra

Abstract

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.