3.2 TVM increases bladder compliance
Derived from time-domain cystometry performed pre- and post-operatively (Figure 2A PRE and 2B POST, respectively), pressure-volume analyses (PVAs) of voiding were established by plotting intra-vesical volume (Vive) against detrusor pressure (Pdet) (Figure 2C and 2D. Peng et al., 2020;2021; Lau et al., 2022); and the trajectory of each PVA shaped a loop demonstrating a voiding cycle. The left border of the loops which displayed progressively increased Vive with slightly elevated Pdet, represented the filling stage; and the slope of the regression line of the left border (red) was measured as the mean compliance (Cm) of the filling phase(Cm=ΔVive/ΔPdet).
Illustrative PVAs showed, when compared with the pre-operative control (Figure 2C PRE), TVM markedly increased the mean compliance of the filling stage as it tilted the regression line counterclockwise and thereby increased the slope of the line (Figure 2D POST). The increased Cm was confirmed by summarized data demonstrating TVM consistently increased Cm in most patients (Figure 3A; 17 out of 22, 77%) and significantly increased the mean value of Cm of the patient (Figure 3B. p<0.05, N=22).