Bladder Compliance Dynamics of Pelvic Organ Prolapse in Women Undergoing Robotic-assisted Sacrocolpopexy

Study Objective: Although mean/static compliance of bladder filling can be readily assayed via cystometry, a protocol measuring compliance dynamics at a specific stage of bladder filling has not been established in human patients. For patients with pelvic organ prolapse (POP), the objective benefits of robotic-assisted sacrocolpopexy (RSCP) surgical intervention for restoring bladder functions, primarily urine storage, have yet to be established. Also, bladder compliance is a viscoelastic parameter that crucially defines the storage function. Therefore, we aimed to investigate the impact of RSCP on bladder compliance of POP patients using a pressure-volume analysis (PVA), which graphically illustrates bladder compliance. Design: A retrospective pre and postoperative study. Setting: Multiple hospitals in Taiwan. Patients: Twenty seven female POP patients (stage ≥ II). Intervention: RSCP for POP repair. Measurements and Main Results: We retrospectively reviewed the pre- and postoperative PVAs for women with POP who underwent RSCP. The mean compliance of the entire (Cm), the early half (C1/2), and the late half (C2/2) of bladder filling were analyzed as primary outcomes. Changes in intravesical volume (ΔVive) and detrusor pressure (ΔPdet) of bladder filling, ΔPdet in the early (ΔPdet1/2) and late (ΔPdet2/2) filling, and postvoiding residual volume (Vres) were analyzed as secondary outcomes. Compared with the preoperative control, RSCP increased Cm (p =.010, N = 27) and C2/2 (p <.001, N = 27) but negligibly affected C1/2 (p =.457, N = 27). Mechanistically, RSCP decreased ΔPdet (p =.0001, N = 27) without significantly affecting ΔVive (p =.863, N = 27). Furthermore, RSCP decreased the ΔPdet2/2 (p <.001, N = 27) but not ΔPdet1/2 (p =.295, N = 27). Conclusions: This is the first report on applying PVA in assaying dynamics of bladder compliance in patients with POP. Our results suggest that RSCP improved bladder storage in women with POP since it increased bladder compliance, particularly in the late filling, possibly by restoring the anatomical location and geometric conformation for bladder expansion.