Introduction: The Artificial Urinary Sphincter (AUS) is currently the standard of care for men with severe Stress Urinary Incontinence (SUI). It's also a treatment option for SUI in women in Europe. Urethral occlusion pressure transmitted by the cuff to the urethra is determined by the Pressure Regulating Balloon (PRB), that cannot be adjusted after implantation. Low pressure will affect functional result on continence, excessive pressure could lead to urethral erosion. The UroMems AUS is an implantable device with a cuff and a Control Unit (CU) which embeds an automatic pump and electronic components. This allows to wirelessly set the device occlusive pressure, thereby personalizing the therapy. The objective of this study is to compare on cadavers the range of urethral occlusion pressure covered by the UroMems AUS compared to the AMS800™(Boston Scientific).
Methods: This study was conducted on 6 cadavers, 3 males and 3 females. Each cadaver was implanted with an AMS800 occlusive cuff, around the bulbous urethra by perineal approach in males, and around the bladder neck by median incision in females. For each cadaver, the cuff was successively connected to the 3 different AMS800 PRB: 51-60 cmH2O, 61-70 cmH2O and 71-80 cmH2O. For each PRB, Urethral Pressure Profilometry (UPP) was done with a Goby™ urodynamic system (Laborie). The AMS800 PRB was then replaced by the UroMems CU. After device calibration, UPP was done for set pressures ranging from 10 to 150 cmH2O by increments of 10 cmH2O. The main outcome of the study was Maximal Urethral Closing Pressure (MUCP). A study correlation was performed between CU set pressure and MUCP.
Results: Cuff size were 4; 4; 4,5 cm for males and 5; 5; 5,5 cm for females. With AMS800 PRB, mean MUCP was 58 cmH2O IC95%[53; 62], 66 cmH2O [65; 68], and 76 cmH2O [70; 81] for the 51-60 cmH2O, 61-70 cmH2O and 71-80 cmH2O PRB respectively. With the UroMems CU, mean MUCP range was from 23 [16; 30] to 120 [108;131] cmH2O for a set pressure range of 10 to 150 cmH2O respectively, as shown in Figure 1. There was a significant correlation between the CU set pressure and the MUCP for both males (r=0,99, p<0,01) and females (r=0,97, p<0,01).
Conclusions: In male and female cadavers, the UroMems CU provides a range of MUCP from 23 to 120 cmH2O, which covers MUCP obtained with the 3 different AMS800 PRB.