Introduction
The urinary bladder collects and stores urine before its disposal. As a hollow organ of high compliance, the pressure of the bladder is elevated slightly in response to a considerable filling volume during the storage1. Impaired bladder compliance is deleterious because aberrantly elevated intra-vesical pressure could lead to upper urinary tract damage2 and/or urinary incontinence3.
The prevalence of pelvic organ prolapse (POP), i.e., pelvic organ(s) protrudes beyond its anatomical confines, is increasing owing to the continuously advancing age, as it affects most commonly women elder than 70 years old4,5. Notably, a retrospective videourodynamic analysis demonstrates decreased bladder compliance is positively correlated with the incidence of POP6. Moreover, when compared with healthy volunteers, patients with stage III-IV POP displays a lower bladder compliance at urgency7, indicating POP patients is associated with a diminished bladder compliance.
Trans-vaginal mesh (TVM), which aims to correct anatomical abnormalities and thereby restore pelvic floor function8, is a minimally invasive therapy for POP9. Though, in 2016, USA Food and Drug Administration issued a notification concerning the long-term safety of the TVM repair10, some TVM kits11,12,13 are so far viable options for treating POP because they offer a successful anatomical reconstruction and satisfied objective outcomes14. Nevertheless, the objective outcome of TVM on the storage function of the bladder, particularly the compliance, has been scarcely investigated.
In the current study, the potential benefit of TVM on bladder storage of POP patients was investigated. For this purpose, history of POP patients with voiding difficulties were reviewed; and their data of urodynamic investigations measured before and after the procedure were analyzed by focusing on changes in bladder compliance and associated parameters. Moreover, as a preclinical study has demonstrated pressure-volume analysis (PVA) as a tool that graphically and conceptually assesses the bladder compliance15; and a retrograde cohort analysis has very recently established PVA in stress urinary incontinence patients16, we established PVA of POP patients and assayed the bladder compliance as the slope of the regression line of the trajectory during the filling stage.