Dysfunctional voiding (DV) is defined by the ICS as ‘an intermittent and/or fluctuating flow due to inadequate/variable relaxation of the external sphincter during voiding in neurologically-normal men’. However, we noted that flowrate and associated voiding contraction patterns can be far more heterogeneous in this group.  

The micturition cycle is complex, involving the central nervous system (CNS), peripheral nervous system (PNS) as well as smooth and striated muscles. Therefore, the cause of DV could be a result of pathology at any of these systems. The presence of concomitant bowel and/or sexual symptoms may indicate if the dysfunction is global pelvic floor or limited to the peri-urethral sphincter (potentially akin to the male-equivalent of Fowler’s syndrome).

The aim of our study was to assess the prevalence of pressure/flow (P/F) patterns and bowel as well as sexual symptoms in men with DV.

We retrospectively classified the P/F of 31 consecutive neurologically-normal (MRI-excluded) men (age: 23-50, median 36 years) with evidence of DV on video urodynamics. 

DV was diagnosed if there is intermittent flow with associated isovolumetric detrusor contractions and/or dilated prostatic urethra with or without intermittent closing of the membranous urethra on the micturating cystogram (strictures are excluded prior to VCMG).
We classified the patients into three original groups: 

1.	Fluctuating P/F, with an out of phase saw-tooth pattern. 
2.	High pressure / low flow (BOOI > 21).
3.	Low pressure / low flow (BOOI < 21).

Bowel and sexual function were assessed using the patient assessment of constipation symptoms (PAC-SYM) and International index Erectile Function (IIEF) questionnaires respectively.

Figure 1 illustrates the prevalence of pressure flow patterns. Only 48% of patients had the expected intermittent flow presentation. 
Bothersome bowel symptoms and erectile dysfunction (ED) questionnaire results were available in 22 patients. 11/22 had bowel or ED symptoms (3/22 had both).

Patients with DV present with a range of voiding patterns with only ~half voiding with the expected detrusor-sphincter dysynergia pattern. The presenting characteristics of DV patients overlap with other bladder outflow obstruction (BOO) aetiologies, therefore emphasising the need for video urodynamics to be the utilised in all men under the age of 50. Only the use of fluoroscopic imaging with pressure-flow data can reliably differentiate between DV and bladder neck obstruction. 

Functional changes can occur in the bladder as a result of BOO. The classification of patients within these groups could indicate the degree or obstruction or how long it has been present. 

~50% present with bowel and/or ED symptoms (~20% with both symptoms). This indicates that pan-pelvic floor dysfunction could be a significant contributing factor in DV. Comprehensive histories should be taken in all patients in order to help delineate DV aetiologies.

Patients with DV have a wide-ranging clinical and urodynamic presentation. This heterogeneity may indicate diverse aetiology and/or severity. Delineating the root cause and severity of DV may allow the development of new therapies or predicting response to current ones.