3.5 TOT increases voiding pressure
Because the mean resistance during voiding was defined as the mean voiding pressure (Pv) divided by the mean urethral flow (Fv; Rv=Pv/Fv); and the Fv can be further calculated by dividing the mean voided volume (Vv) by the voiding time (Tv; Fv=Vv/Tv). Thereby, the relationship between the mean urethra resistance and the derived parameters can be described as Rv=Pv/[Vv/Tv]. We hence further assayed the changes in Pv, Vv, and Tv in response to surgery to specify the impact of TOT. When compared with pre-operative controls (Figure 4B PRE), TOT post-operatively increased individual Pv in most patients (POST; 21 out of 26, 80%) and significantly increased the mean value of Pv of patients. In contrast, individual data demonstrated that neither Vv (Figure 4C; 9 patients, 34% increased; 16 patients, 62 % decreased; 1 patient, 4% unchanged) nor Tv (Figure 4D; 8 patients, 31% increased; 17 patients, 65 % decreased; 1 patient, 4% unchanged) displayed a majority change (>75%). Moreover, no statistical significance was evidenced in the mean values of Vv and Tv of patients. These results indicated that in accompanied with an increased outlet resistance, TOT post-operatively elevated bladder pressure during voiding.