Time-series analysis of urethral electrical conductance measurements in the assessment of unstable urethral pressure: results in normal patients and in those with genuine stress incontinence.
It is well established that urethral pressure variations occur in patients with or without urinary incontinence, but to what extent they contribute to a patient's symptoms remains unclear. Previous work has suggested that in stress incontinent patients, a rise in bladder neck electrical conductance (BNEC) occurs simultaneously with a fall in urethral pressure, and that this represents bladder neck opening. Six patients with genuine stress incontinence (gsi), and six normal controls underwent simultaneous urethral pressure and BNEC measurements, the results being subjected to time-series analysis, to determine whether the previous finding could be confirmed statistically, and to establish whether a similar association was present in normal women. All six patients with gsi and five of the normal patients had unstable urethral pressure. Estimated cross-correlation of differenced data for the two parameters showed a significant negative correlation at zero time lag in three patients with gsi and two of the control group. There was no significant correlation between the two parameters in the other seven patients. We conclude that the previous finding of a correlation between urethral pressure variation and BNEC, suggesting bladder neck opening occurs as urethral pressure falls in patients with gsi is confirmed, but appeared to be present in only 50% of patients; the finding is just as likely in normal patients, and therefore whilst it may be of relevance to the severity of symptoms, could not be held to have any aetiological significance.
Ramsay
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Department of Obstetrics and Gynaecology, University of Newcastle Upon Tyne, England.
Hilton
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Cox
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D000328:Adult; D000368:Aged; D004553:Electric Conductivity; D005260:Female; D006801:Humans; D008875:Middle Aged; D011312:Pressure; D012016:Reference Values; D013223:Statistics as Topic; D013997:Time Factors; D014521:Urethra / Q000503:physiopathology*; D001743:Urinary Bladder / Q000503:physiopathology; D014550:Urinary Incontinence, Stress / Q000503:physiopathology*