[Diagnosis of infravesical obstruction in patients with benign prostatic hyperplasia].

To improve reliability of the diagnosis of infravesical obstruction (IVO) in patients with benign prostatic hyperplasia (BPH), we examined 80 BPH patients (mean age 58.2 +/- 2.1 years). The examination included evaluation of complaints by IPSS, ultrasound investigation with determination of prostatic size and residual urine, and urodynamic tests: uroflowmetry, miction cystometry. We came to the conclusion that symptoms of BPH, size of the gland, amount of residual urine and maximal volumetric miction velocity not always evidence for IVO. To raise reliability of IVO diagnosis we propose the following formula: D1 = 0.818 x S(max) +0.0006 x S(min) +0.215 x Q(max) - 0.478 x Q(aver), where D1 is a discriminant function; S(max) is a maximal linear size of the prostate; S(min) is a minimal linear size of the prostate; Q(max) is maximal volumetric flow rate; Q(aver) is mean volumetric flow rate. If D1 > or = 2.85, IVO is definite. If D1 < or = 2.85, IVO absence is more probable. Thus, the proposed formula provides more reliable diagnosis of IVO in BPH patients than assessment of clinical indices.