[Quantification of bladder-outlet obstruction in males: standard method vc VBN method].
OBJECTIVE
To compare the merits of two methods, standard (Abrams-Griffiths number, Schafer's classification, etc.) and VBN, to study bladder-outlet obstruction in men with benign prostatic hyperplasia (BPH).


METHODS
The parameters deduced from both methods and from repeated pressure-flow studies were computed for a population of patients with BPH. Correlation coefficients between standard and VBN parameters were systematically evaluated. Test-retest reliability and inter-rater reliability of the VBN parameters were investigated.


RESULTS
The VBN obstruction parameter was linearly corelated to the A-G number (R = 0.992) and thus is related to the provisional ICS obstruction nomogram. A simple modification to the standard index projected isometric pressure (PIP) yields an mPIP parameter strongly correlated with the VBN detrusor contraction-strength parameter (R = 0.962). VBN analysis reveals minor phenomena such as premature fading of the detrusor contraction to be responsible for much of the void-to-void variability of pressure-flow studies. Consequently, the primary VBN obstruction and contraction-strength parameters exhibit better test-retest and inter-rater reliability than the standard parameters and are less sensitive to changes in testing circumstances (bladder volume, urethral catheter size and psychological factors).


CONCLUSIONS
With the standard approach to test bladder obstruction, two values: A-G and mPIP, derived from pressure-flow studies, best qualify the patient's voiding status. These parameters are simple to calculate but are sensitive to testing variations and minor phenomena. The VBN approach is more complicated, but its parameters for obstruction and detrusor contraction strength are less dependent on testing variations.
Valentini
F A
FA
Equipe Mixte Inserm EMI 03 49, université Pierre-et-Marie-Curie, Paris, France. francoise.valentini@jrs.ap-hop-paris.fr
Griffiths
D J
DJ
Zimmern
P E
PE
Besson
G R
GR
Nelson
P P
PP
D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008297:Male; D008875:Middle Aged; D011312:Pressure; D011470:Prostatic Hyperplasia / Q000150:complications; D001748:Urinary Bladder Neck Obstruction / Q000175:diagnosis* / Q000209:etiology; D014563:Urodynamics