To investigate the effect of pelvic floor relaxing position on voiding using uroflowmetry parameters in patients with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH).

We conducted a cross-sectional study from May 2017 to Nov 2017 and included men with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). A total of 71 patients were enrolled in the study. The uroflowmetry were performed in both standing and pelvic floor relaxing voiding position (unilateral abduct hip and flex knee) for each patient. The post-void residual urine (PVR) was measured using a portable ultrasound bladder scanner after each voiding. The maximum flow rate (Qmax), average flow rate (Qave), voided volume (VV) and PVR values were compared between the two different voiding positions. Statistical analyses were done using Stata 14.1®. Paired t-test and Paired sign test were done for parametric and nonparametric comparisons, respectively; P < 0.05 was considered significant.

A total of 71 men with a median age of 69 (43, 85) years were evaluated. The median void volume for the standing and pelvic floor relaxing positions in the patient group were 277.5 (150.8, 744) and 291.2(156.4, 866.2)ml, respectively with no statistically significant difference between groups. The median Qmax values for the standing and pelvic floor relaxing position in the patient group were15(6.1, 44.2) and 16.4 (5.3, 45.9)ml/s, respectively. The median Qave values were 8.4(4, 19)and 8.3(4.5, 20.9) ml/s, respectively. The mean PVR values were 50.30 ± 68.07 and 63.56 ± 72.28 ml, respectively.

The median Qmax values for the standing and pelvic floor relaxing position reach statistical significance (P value 0.041). The mean PVR values for the standing and pelvic floor relaxing position reach statistical significance (P value 0.002). 
Comparison of uroflowmetry results in both positions showed statistical differences for higher Qmax and larger residual urine volume in the pelvic floor relaxing position relative to the standing position.

The uroflowmetry parameters seem to be affected by the voiding positionin men with lower urinary tract symptoms due to benign prostatic hyperplasia. It can be assumed that some benign prostatic hyperplasia patients might have some components of pelvic floor muscle dysfunction. Therefore, pelvic floor relaxing voiding position may be applied in these patients. More research is needed to further study in the patient with pelvic floor dysfunction.