Superficial EMC of the pelvic diaphragm (introitus EMG) in the diagnosis of urinary stress incontinence

The EMG of the pelvic diaphragm is primarily used to diagnose urethrovesica l dyssynergy. It is well known that many stress-incontinent women cannot co ntract the M. levator ani on demand, that there is a damage of the pelvic d iaphragm innervation sub partu, and EMG-based biofeedback trainers are succ essfully used in the therapy of urinary and stool stress incontinence. Howe ver, the EMG has not been used to further differentiate stress incontinence or incompetence of the pelvic diaphragm until now. Objective: Can the EMC verify pelvic diaphragm incompetence? Methods: 267 superficial EMG were taken from 236 incontinent and continent women. Incontinence in nonpregnant women was confirmed by urodynamic invest igations, which included urethrocysto-tonometry, perineal sonography, cysto scopy and micturition X-ray. 33 pregnant women, some of them were examined several times follow-up study, were separated in a special group. A three-p ole electrode (introitus EMC) measured the summation potentials of the pelv ic diaphragm, with certain frequencies amplified. Results: 72 women showed no signs of incontinence, 87 revealed stress or co mbined stress-urge-incontinence while 42 had pure urge incontinence. The EM G revealed potentials between 2 and > 20 mu V that were easy to reproduce. Stress incontinent women exhibited significant lower potentials than non st ress incontinent women (7,856 +/- 4,256 vs. 14,069 +/- 4,489, p < 0.0001). However, no further correlation to the degree of incontinence or descensus could be shown. During pregnancy, women showed lower potentials and a sign. Decrease of electrical activity correlating to the number of childbirths ( p < 0.05). Conclusion: Most stress-incontinent women reveal a weakness of the pelvic d iaphragm which can easily be verified by the introitus EMG. Beside pressure transmission and bladder neck descensus the pelvic diaphragms ability to c ontract is an independent etiological factor of stress incontinence.