Denervation and re-innervation of the urethral sphincter in the aetiology of genuine stress incontinence: an electromyographic study.
OBJECTIVE
To investigate the role of altered innervation of the urethral sphincter in the genesis of genuine stress incontinence.


METHODS
Prospective observational study.


METHODS
Tertiary referral centre urodynamics unit.


METHODS
Sixty-eight women, 33 with urodynamically proven pure genuine stress incontinence and 35 controls without urinary symptoms.


METHODS
Concentric needle electromyography of the urethral striated sphincter.


METHODS
The means of motor unit potential duration, number of changes in polarity and the amplitude of individual motor unit potentials were compared between the two groups.


RESULTS
There was no statistically significant difference in motor unit potential duration (P = 0.87) or in the number of changes in polarity (P = 0.85). There was a trend towards a higher amplitude of motor unit potentials in the control group (P = 0.07).


CONCLUSIONS
Our findings suggest that denervation and re-innervation of the striated urethral sphincter following trauma to the pelvic floor, such as that occurring during childbirth, is not a major aetiological factor in the development of genuine stress incontinence.
King's College Hospital, London.
C G
CG
Barnick
L D
LD
Cardozo
D000200:Action Potentials; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004576:Electromyography; D005260:Female; D006801:Humans; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology; D011446:Prospective Studies; D014521:Urethra / Q000294:innervation* / Q000503:physiopathology; D014550:Urinary Incontinence, Stress / Q000209:etiology* / Q000503:physiopathology