Urethral diverticulectomy is known to be associated with Stress Urinary Incontinence (SUI) both at presentation and after diverticulectomy but, due to the rarity of the condition, there is little knowledge of risk factors for developing post-operative incontinence. Interpretation of MRI images before diverticulectomy aid surgical planning and we hypothesise may also give metrics to help understand which patients may be at an increased risk of post-operative urinary incontinence. We report our updated series on MRI configurations of urethral diverticulum in particular in relation to the incidence of de novo stress urinary incontinence after urethral diverticulectomy.

We retrospectively analysed records of 122 consecutive patients undergoing urethral diverticulum excision at a single  unit over a 13 year period (2005-2018). Data collected included symptoms, surgical and obstetric history, operative details, MRI and Video Urodynamic (VUD) data and subsequent interventions. MRI images were re-reviewed by a specialist Uro-Radiologist to gather data from the MRI on antero-posterior (AP)/transverse/length measurements of the diverticulum, angle of the diverticulum around the urethra, urethral length, distance of the Os from the bladder neck and urethral meatus, and loculations. Statistical analysis was performed using Chi-squared test for categorical variables and Student's unpaired T-test for continuous variables.

Of our cohort of 122, 81 patients had full MRI and VUD data available. This cohort was then separately analysed. Median age was 45 years and all patients had a minimum 12month follow-up. 35 patients did not have urodynamic stress urinary incontinence (USUI) pre or post-operatively. 17 patients had pre-operative USUI which persisted after diverticulectomy and 23 patients had de novo post-operative USUI. The MRI findings for these groups are shown in Table 1.

We subsequently compared patients without USUI with those who developed de novo SUI. Statistical analysis showed that urethral diverticulum circumferential configurations are associated with de novo SUI post-operatively (p<0.05) which was also supported by the finding of a greater angle of diverticulum involvement around the urethra in cases with post-operative de novo SUI (p<0.05). AP and length measurements did not show any statistical significance but there was a statistically significant increase in transverse measurements of the diverticulum in patients with de novo SUI (p<0.05). Other MRI and patient risk factors were analysed but not found to be associated with developing de novo SUI in this setting although this may change as the data matures and the size of the cohort expands.

This data suggests that MRI configuration could be used to aid pre-operative counselling of patients and identifying those at risk of developing post-operative SUI in this condition. Maturation of this cohort will hopefully strengthen this data and identify other factors that can be used to risk-stratify patient risk of post-operative de novo SUI after urethral diverticulectomy.