HOW TO EVALUATE THE “TRUE” BLADDER CONTRACTILITY IN PATIENTS UNDERGOING PELVIC ORGAN PROLAPSE SURGERY?
KITTA, Y. KANNO, M. OUCHI, M. TSUKIYAMA, M. NAKAMURA, K. MORIYA, N. SHINOHARA;
Department of Renal and Genitourinary surgery, Hokkaido Univ. Graduate Sch. of Med., Sapporo, Japan.
Introduction: Pelvic organ prolapse (POP) may cause bladder outlet obstruction and decrease detrusor contractility. Bladder contractility consists of contractile strength and duration. However, the variable method for evaluating the contraction duration is not well validated. We previously reported that the parameter which represent when reach the maximum Watts factor (WF) (Wmax%) could provide the bladder contraction sustainability. However, Wmax% could not represent the pattern of detrusor contraction completely throughout micturition. Because the WF curve was spiny appearance which could not be a smooth line (because of biological data) and Wmax% itself could not represent the duration of bladder contractility. Wmax% alone could not represent the patterns of bladder energy using throughout the voiding cycle.
Objective: At this point, we have no simple parameter for evaluating the pattern of detrusor contraction (“true” bladder contractility). In the present study, we provided further insight into the detrusor contraction pattern using a new pressure flow study (PFS) parameter. We focused on the detrusor contractility pattern of POP patients pre and post operation using PFS data.
Methods: In the present study, we calculated the percentage of when reach the peak of WF (Wmax%) and area under the WF curve of throughout the voiding cycle (WF-AUC) (Figure (a)). A normal detrusor contractility pattern show a sharp increase at the initiation of micturition, and slight increasing to the end of micturition, moreover duration of bladder contraction is long enough. However, patients with impaired detrusor contractility show a fading contraction pattern (decreasing to the end of micturition). Wmax % and WF-AUC could represent the detrusor contractility of the entire picture compared to previous parameters. Sixteen women with advanced anterior vaginal wall prolapsed were urodynamically evaluated. PFS were thirdly performed pre, post 1week and post 3 months after POP surgery. Maximal urinary flow rate (Qmax), residual volume, detrusor pressure at maximal flow (Pdet at Qmax), Wmax, Wmax % and WF-AUC were measured.
Results: The mean age (range) of patients was 74 (63-84). The mean pre and 1week and 3 months postoperative Qmax were 10.0 ± 6.0, 8.4 ± 6.5 and 10.9 ± 7.6 ml/s, respectively. The mean Residual volume were 145.6 ± 135.7, 218.0 ± 120.6 and 114.9 ± 102.3 ml, respectively. Residual volume were once increased significantly 1 week after the operation (P<0.05). However, there were not significantly changed pre and 3months postoperatively. The mean pre and postoperative Pdet at Qmax were not changed significantly (23.0 ± 21.4, 16.5 ± 11.9 and 18.0 ± 11.4 cmH2O, respectively). Although both parameters Wmax (5.1 ± 3.4, 3.6 ± 2.3 and 4.7 ± 2.8 W/m2, respectively) and Wmax % (64.6 ± 24.7, 58.1 ± 26.5 and 51.7 ± 43.5, respectively) have not changed significantly, WF-AUC was increased significantly 3 months after the operation compared to 1 week (832.0 ± 660.0, 457.0 ± 487.0 and 977.2 ± 617.8, respectively (P<0.05)) (Wmax% did not increased, however WF-AUC was increased up to 2-times, typical case: figure (b)). Wmax is the maximum instantaneous power of bladder contraction, whereas WF-AUC can confirm the improvement of detrusor contraction throughout micturition to assess overall detrusor contractility.
Conclusions: Our study confirmed that POP surgery change the detrusor contractility pattern of anterior pelvic organ prolapsed patients. The measurement of WF-AUC provides new approach to the bladder contraction pattern.