Terminal dribbling in male patients with lower urinary tract symptoms: relationship with International Prostate Symptom Score and with intravesical prostatic protrusion

One of the difficulties encountered in earlier studies regarding TD was the lack of a clear definition ensuring that patients could discriminate it from post-void dribbling. The current concept of TD was first addressed on the ICS male questionnaire and has been defined by ICS recommendations in 2002 [ 4, 7]. Before this definition, the studies performed in 1990s used various definitions of TD [ 12– 16]. Moreover, several reports have regarded TD as an initial or mild form of post-void dribbling [ 13– 15]. Post-void dribbling was recently determined to be one of post-micturition symptoms that is distinct from TD. The pathogenesis of post-micturition dribbling involves weakness of the bulbocavernosus muscle, which results in failure to evacuate urine that has pooled and trapped in the bulbar area of the urethra after voiding [ 17]. Additionally, the ICS previously removed the term “terminal dribbling” because of its similarity with post-void dribbling, which could be the main reason why there have been few studies on this issue [ 18]. To achieve the consistency, we conducted face-to-face interview by a single investigator using standardized definition of TD. Clinical studies on this topic should describe the demographic characteristics of the subjects, the prevalence of TD, the questionnaire used, and the definition of TD. Table  4 summarizing the previous studies related with TD indicates that the prevalence of TD is much greater in the LUTS patients than in the community people.

Although few studies have been perform to investigate TD, high rates have been observed in patients with LUTS in both Western and Asian populations [ 2, 4, 19]. The ICS–‘BPH’ study reported 91–96 % of symptom prevalence of TD in BPH patients and 73–79 % in community people by ICS male questionnaire [ 4]. Korean study using translated version of ICS male questionnaire also showed that 86 % of male patients with LUTS had the symptom of TD, which was the second most common symptom even though TD has not been regarded as a bothersome symptom [ 2]. In addition, the reported prevalence of TD in elderly men was less than that of middle aged men [ 4]. This may imply that TD is an early obstructive symptom and that the patients with TD get used to this symptom as time passes by. Interestingly, our results were consistent with the previous study that the prevalence of TD in male LUTS patients was higher in their 60’s compared with in their 50’s and 70’s. TD does not seem to be the sign of the early stages of LUTS because IPSS total score and IPSS QoL score in TD group were significantly higher than those in non-TD group.

Since there have been few studies investigating TD, its associations with LUTS and several clinical parameters have not been well characterized so far. In this study, TD had an association with voiding subscore in IPSS but no associations with serum PSA level, prostate volume, and prostate transitional zone volume. Traditionally, TD has been regarded as one of the voiding symptoms [ 4, 6, 13]. In addition, IPP has been reported to be associated with voiding symptoms [ 9, 20, 21]. In the present study, IPSS voiding subscore had a strong correlation with TD and IPP emerged as a significant risk factor for uroflowmetry-confirmed TD.

Earlier reports have tended to put an emphasis on objective tools such as uroflowmetry. However, 48 % of the patients who reported TD did not show any objective evidence of TD on uroflowmetry [ 6]. In our study, about 30 % of the patients did not show the typical finding of TD on uroflowmetry. One of the reasons of this result is probably that TD does not happen all the time in some patients. Another reason to be considered is the large amount of urine volume that the patients try to void when they are taking the uroflowmetry test.

This study has several limitations. First, pressure flow studies were not performed, and as a result we could not confirm bladder outlet obstruction of each patient. However, the recent guideline recommends that pressure flow studies should be considered before invasive treatment in men with a Qmax greater than 10 ml per second and are not necessarily needed in the patients whose maximum flow rate is less than 10 ml per second [ 22]. Second, we did not use the entire ICS male questionnaire because it contains a large number of questions. Notably, however, the initial developers of the questionnaire have recommended the short form ICSmaleSF questionnaire omitting duplicate or redundant items [ 19].