Dysfunctional voiding in women: which muscles are responsible?

Objective To analyse the striated external urethral sphincter (EUS) and pelvic floor muscles using two different electromyography (EMG) techniques in women with dysfunctional voiding and/or urinary retention. Patients and methods Fifteen women (mean age 38.2 years, range 18-61) with dysfunctional voiding and/or unexplained voiding dysfunction associated with urinary retention were examined neurologically and urologically; urodynamics and kinesiological EMG of the bilateral pubococcygeal and external urethral striated sphincter muscles were obtained. In an additional neurophysiological session. concentric-needle EMG of the external urethral sphincter was performed. Results Kinesiological EMG recordings revealed inappropriate pelvic floor muscle activation during voiding in 11 and EUS activation in four women. Concentric needle EMG of the EUS revealed complex repetitive discharges in the four women with inappropriate urethral sphincter activation recorded by kinesiological EMG during voiding. Biofeedback training led to improvement in women with inappropriate pubococcygeal activation but not in those with urethral sphincter complex repetitive discharges. Conclusion Urodynamic examinations in combination with kinesiological EMC examination of the pubococcygeal and external urethral sphincter muscles revealed two groups of women with dysfunctional voiding, Further diagnostic evaluation of such patients with concentric-needle EMG is mandatory. The differentiation of the two groups is therapeutically relevant.