Comparative study of urodynamic tests after AMS 800 and ZSI 375 insertion

Retrospective, non-randomised, single-centre study.

Comparative study of urodynamic tests in patients presenting social continence after AMS 800 or ZSI 375 insertion.

Study was open to patients with social continence, implanted with AMS 800 or ZSI 375. Vesical pressure (VP), urethral functional length (FL), maximal urethral pressure (MUP), maximal urethral closure pressure (MUCP), maximal urinary flow rate (Q_max) were registered with standard urodynamic equipment.

From March 2012 to September 2014, 27 male patients with AMS 800 and 28 with ZSI 375 were recruited. In the AMS 800 group mean VP was 25.03 cmH₂O (range 13-47), mean FL 31.96 mm (range 20-52), mean MUCP 88.29 cmH₂O (range 32-160), mean MUP 119.55 cmH₂O (range 77-180), mean Q_max 22.86 mL/s (range 5.6-54.6). In the ZSI 375 group, mean VP was 24.89 cmH₂O (range 6-40), mean FL 30.53 mm (range 12-87), mean MUCP 70.11 cmH₂O (range 38-108), mean MUP 99.89 cm H2O (range 63-134), and mean Q_max 19.25 mL/s range (7.3-39.6).

Results of urodynamic tests are similar for both artificial urinary sphincters. AMS 800 cuff pressure over 70 cmH₂O could be explained by the pelvis pressure and the difference of altitude between the pressure-regulating balloon (PRB) and the cuff. ZSI 375 pressure-regulating tank (PRT) is not influenced by these factors. Very high MUP could be explained with too tightened cuffs.

AMS 800 and ZSI 375 urodynamic tests are similar. Pressure of the pelvis and difference of altitude between the AMS balloon and the cuff can lead to high MUP.