This is the first study to clarify what urinary background causes post micturition dribble (PMD). PMD is the symptom of involuntary loss of urine immediately after voiding and classified as a post micturition symptom. There was a positive trend between PMD prevalence and age, but PMD is not rare in non-elderly men. Bulbar urethral massage and pelvic floor exercise are known to relieve PMD. That guidance is needed for patients with PMD however we focused on the fact that men with PMD do not have PMD every time they void. There are some reports on prevalence of PMD, but it has not been reports on what urinary background causes PMD. We thought that the investigation what urinary background causes PMD enables more detailed lifestyle guidance. The purpose of this study is to clarify what urinary background causes PMD and how to prevent PMD.

Twenty volunteer men with PMD used portable uroflowmetry for 48 hours between 2018 and 2021. Men with LUTS or incontinence other than PMD were excluded. We targeted non-elderly volunteers to exclude the effect of BPH on urination. They recorded symptoms of PMD (grade and timing) and strength of desire to void (no, weak, normal or strong) for each voiding. They urinated in standing position and shake their penises well after voiding. Bulbar urethral massage after voiding was prohibited. We investigated the risk factors of PMD and the correlation between strength of desire to void and PMD or parameters measured by UFM. Using the value of the difference from the average of the parameters for individual, we judged what kind of urinary background.

Median age of volunteer men was 36 years old. Fifteen percent of them had PMD every day and 65% of them had PMD more than once a week. Twenty volunteers experienced a total of 208 voiding. Twenty seven percent of voiding had PMD. All PMD wet only underwear. The most frequent timing of PMD was when they put on underwear after voiding. Low voiding volume was statistically significant risk factor for PMD in univariate analysis(p<0.01).  Flow time, maximum flow rate and average flow rate ware not significant factors for PMD. There was a statistically significant correlation between the strength of desire to void and voiding volume (p<0.01). The voiding with no or weak desire to void caused PMD statistically significantly compared to voiding with normal or strong desire to void (figure;36% vs 21%, p=0.03).

In order to facilitate guidance to patients with PMD, we investigated the correlation between PMD with desire to void as well as UFM data. Low voiding volume and the voiding with unclear urinary sensation were risk factors for PMD on non-elderly men without LUTS. The mechanisms of PMD are presumed to failure of the pelvic floor muscles or external urethral sphincter. They cause urine residue in the bulbar or prostatic urethra after voiding. The pelvic floor muscles or external urethral sphincter may not work well when the amount of urine storage is small. Avoiding the voiding with unclear urinary sensation contribute to prevent PMD. We are sure that the instructing to avoid voiding with unclear urinary sensation is easy to understand for the male patients with PMD.

Low voiding volume and the voiding with unclear urinary sensation are risk factors for PMD. These data suggest that instructing male patients with PMD to avoid voiding with unclear urinary sensation contribute to prevent PMD.

Continence 7S1 (2023) 100834
DOI: 10.1016/j.cont.2023.100834