[The urodynamic nomogram in defining the degree of obstruction in patients with benign prostatic enlargement--defining clear obstruction].

OBJECTIVE: In order to define clear urodynamic obstruction, all patients from unclassified zone of the nomograms are to be allocated in the zone of obstruction or out of obstruction combining the parameters of different nomograms. Then, to analyze difference of the physical and radiological variables between obstructed and unobstructed groups. Finally, to determine the percentage of the patients with additional urinary bladder co morbidities in clear obstruction zone.

SAMPLE AND METHODOLOGY: 102 patients with proved BPE underwent complete urodynamic investigations, (uroflowmetry, cystometry and pressure/flow studies). All methodology of measurement and definitions were based on the definitions of the International Continence Society. Basic urodynamical data were manually plotted on the Abrams-Griffiths, URA, ICS and Schafer nomograms; A/G number was calculated as well. Then, patients were allocated in the region of clear obstruction from II region of Schafer nomogram by the several models (URA number of > or = 29 cmH20, according to the strength of detrusor contraction, opening detrusor pressure > or = 40 cmH2O, PdetQmax > 50 cmH2O with Qmax < 15 ml/s), comparing matching degree to the ICS nomogram.

RESULTS: Combining URA > or = 29 cmH2O (group-specific urethral resistence) and II zone of the Schafer nomogram the best allocation of the patients and best fitting to the ICS nomogram was achieved (99.1% of the cases). 65 patients (63.7%) went in the clear obstruction zone and 35 patients (36.3%) in the unobstructed zone. Student test, with 2-tail level of significance showed difference in the detrusor opening pressure (p < 0.01) among groups, although there is no difference in the premicturation detrusor pressure (p > 0.05), but there is clear difference in the duration of the detrusor contraction between obstructed and unobstructed groups (DCD; p < 0.005), independently of the grade of the detrusor contraction (GDC; p > 0.05). Obstructed group has a smaller cystometric capacity (p < 0.05), although there is no difference in the volume of voided urine (p > 0.05). Noticed is increased incidence of the detrusor instability in the obstructed group (42% versus 22%, p < 0.0005). Analyze of physical variables has shown that there is a difference in the prostate volume among the groups (p < 0.05), and the patients age (p < 0.05), albeit there is no difference in the level of I-PSS, QOL scores (p > 0.05) and post void residual urine volume (p > 0.05), as well. Out of the 65 obstructed patients, only 23 patients (35.3%) have uncomplicated urodynamical obstruction, while other 42 patients (64.7%) have additional detrusor instability or hypocontractility, or combination of both (10.7%). 8 patients (25%) from unobstructed group have detrusor instability (presumable idiopathic instability), and for the 14 patients (38%) detrusor hypocontractility was detected.

CONCLUSION: Combination of the II zone of the Schafer nomogram and URA > or = 29 cmH2O increases accuracy of defining clear urodynamic obstruction, achieving better accordance with ICS nomogram, as well. It has been shown that almost two third of obstructed patients have a bladder comorbidities (detrusor instability and hypocontractility), while more than half of unobstructed patient have similar problems as a cause of the lower urinary tract symptoms.