Influence of ATOMS implant on the voiding phase of patients with post-prostatectomy urinary incontinence

Objective To assess changes in voiding phase, especially urethral resistance after post-prostatectomy urinary incontinence (PPI) treatment with the Adjustable TransObturator Male System (ATOMS). Material and Methods A longitudinal prospective study was performed on 45 men treated with ATOMS for PPI, with the intention to evaluate the changes produced by the implant on the voiding phase. Patients with preoperative urodynamic study were offered postoperative urodynamic evaluation, and both studies were compared. The following urodynamic date were evaluated: maximum voiding detrusor pressure, detrusor pressure at maximum flow rate, maximum flow rate (Qmax), voiding volume, post-void residue, bladder outlet obstruction index (BOOI), urethral resistance factor (URA), and bladder contractility index (BCI). The statistical analysis used were the mean comparison test for dependent groups (Student's t test) for parametric variables and the Wilcoxon test for non-parametric variables. The signification level was set at 95% bilateral. Results A total of 37 patients (82.2%) used zero pads/day at the time of urodynamic postoperative evaluation and pad-test evolved from 592 +/- 289 ml baseline to 25 +/- 40 ml (p = 0.0001). Significant differences were observed in Qmax (15 +/- 8.3 before and 11 +/- 8.3 after surgery; p = 0.008), voiding volume (282 +/- 130.7 before and 184 +/- 99.92 after surgery). BOOI (-12 +/- 23.9 before and -2 +/- 21.4 after surgery; p = 0.025) and BCI (93 +/- 46.4 before and 76 +/- 46.0 after surgery; p = 0.044). In no case did we observe postoperative bladder outlet obstruction, according to URA parameter below 29 cm H2O in all cases. There was not a significant variation either in post-void urinary residual volume (15 +/- 47.4 before and 14 +/- 24.2 after surgery, p = 0.867). Conclusions The ATOMS implant induces a decrease of Qmax, voided volume, and bladder contractility and an increase of BOOI. However, our findings suggest that ATOMS device does not cause bladder outlet obstruction.