Can urodynamic diagnosis of dysfunctional voiding/external sphincter nonrelaxation be made on two-channel pressure-flow study without video-urodynamics, electromyography, or urethral pressure profilometry? Plateau detrusor pattern in perspective.

Aims: urodynamic diagnosis of dysfunctional voiding/external-sphincter nonrelaxation (DV/EUSD) needs assistance of specialized testing namely urethral pressure profilometry (UPP), electromyography (EMG), and/or videofluoroscopy (VUDS). We aimed to find a predictive model based on standard pressure-flow study without need for specialized testing.
Material and Methods: In this retrospective study (2017-2021), clinical and urodynamic data of adult men and women presenting with voiding dysfunction was collected. Mandatory inclusion criteria were availability of all-(1) findings of clinical examination and neurological status, (2) a valid filling cystometry and pressure-flow study (with active detrusor contraction), (3) a final clinic-urodynamic diagnosis. Voiding cystourethrography (VCUG) was performed to confirm the location of obstruction.
Results: Data of 218 participants (178♂, 40♀) was eligible. Plateau detrusor contraction pattern was observed in 89.0% of men and 86% of women with DV/EUSD; whereas only 7.5% men and no women with other obstructions demonstrated this pattern. Forward likelihood Logistic regression analysis revealed presence of plateau pattern, lower bladder outlet obstruction index (BOOI), and smaller difference between Pdetmax and PdetQmax highly predictive of presence of DV/EUSD in men as per the following equation-Y = -9.900 + (0.085 × BOOI) + (0.123 × pdetmax - pdetQmax) + (4.061 × detrusor pattern). A kattan-type nomogram was constructed based on the above equation. In women, presence of plateau pattern alone was highly predictive of DV/EUSD.
Conclusion: Diagnosis of DV/EUSD can be accurately predicted using parameters of three-channel urodynamics (plateau pattern, BOOI, Pdetmax-pdetQmax) minimizing need for specialized testing.
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