Stress urinary incontinence may be caused by urethral
hypermobility, intrinsic sphincter deficiency (ISD), or a combination
of both. Identification of
an open bladder neck at rest on videourodynamic studies (VUDS) is
diagnostic of ISD in women, and the “gold standard.”
A valsalva leak point pressure (VLPP) ≤65cm H2O
is also considered suggestive of ISD.
We reviewed VUDS and VLPPs to determine the correlation of
findings and express the probability of having an open bladder neck
when taking VLPP into account.
Methods
The VUDS and VLPPs of 132 adult women who demonstrated
stress incontinence were retrospectively reviewed. All women with prolapse were reduced prior
to VLPP. All patients were
stratified into “open” or “closed” bladder neck categories, depending
on the interpretation of VUDS by a single senior reviewer (KJK). Mean VLPPs for each group were compared using
the Kruskal-Wallis test. Logistic
regression was used to calculate a coefficient for VLPP, which was
used to determine risk ration of having open or closed bladder neck.
Results
Forty-nine of 132 patients had closed bladder necks
on VUDS, with a mean VLPP of 87cm H2O (95% confidence,
77-97cm H2O). Eighty-three of 132 patients had open bladder
necks at rest on VUDS, with a mean VLPP of 67cm H2O (95%
confidence, 61-74cm H2O).
Differences in mean VLPP were highly statistically significant
(P,0.0027) between groups. Predicted
probability of an open bladder neck versus VLPP is not less than 50%
until 100cm H2O. At
a VLPP of 120cm H2O, a closed bladder neck was falsely
predicted on VUDS in 36% of patients with our model.
Conclusions
VLPP alone was not predictive of VUDS in this series.
Although the mean VLPP between groups was statistically significant,
there is a continuum between pure ISD and stress urinary incontinence
due to hypermobility. If surgical intervention other than pubovaginal sling is entertained,
both VLPP and VUDS should be performed preoperatively.
Direct
correspondence to:
