Bladder compliance dynamics of pelvic organ prolapse patients subjected to robotic-assisted sacrocolpopexy

Abstract

Purpose Though a static compliance over the entire filling phase of the bladder can be easily assayed from the cystometry, a protocol measuring the dynamic compliance at a specific filling stage has not been established in human subjects/patients. As objective benefits of robotic-assisted sacrocolpopexy (RSCP) to the bladder function, particularly urine storage, of pelvic organ prolapse (POP) patients wait to be established, this study investigated the impact of RSCP on the bladder storage by focusing on its impact on compliance using the pressure-volume analysis (PVA), a protocol used to measure compliance dynamics in animals. Materials and Methods: Pre- and post-operative PVAs derived from urodynamic studies of a total of 27 female POP patients, who underwent RSCP for prolapse stage ≥ II (POP Quantification system) were retrospectively reviewed. Bladder compliance, infused volume, and threshold pressure were analyzed. Results: Compared with the pre-operative control, RSCP increased the mean compliance of the filling phase (p<0.01, N=27). Notably, RSCP increased the compliance of the late half (p<0.01, N=27) but displayed a negligible effect on that of the early half (p>0.05, N=27) of the filling phase. Mechanistically, RSCP decreased the change of detrusor pressure (p<0.01, N=27) without significantly affecting that of infused volume (p>0.05, N=27). Furthermore, RSCP decreased the ΔPdet in the late half (p<0.05, N=27) but not that in the early half (p>0.05, N=27) of the filling phase. Conclusions: RSCP improved bladder storage as it increased bladder compliance, particularly the late filling phase; possibly by restoring anatomical location and geometric conformation for bladder expansion.