Occlusive Properties of Transrenal Ureteral Occlusion Self-Expandable Metallic Stents: 3D-Printed Phantom and Ex Vivo Studies

Newly developed transrenal ureteral occlusion self-expanding metallic stents (SEMSs) are applied in patients with inoperable fistulas. In this study, the occlusive properties of M- and D-type occlusion SEMSs were investigated in 3D-printed phantom and ex vivo porcine urinary tracts. In the former, the mean bursting pressure causing leakage of contrast medium through the occlusion SEMS was relatively higher in M-types (42.8 ± 3.8 mmHg) than in D-types (38.8 ± 3.8 mmHg), without a statistical difference (p = 0.075). In the latter, the bursting pressure causing leakage through the M-type occlusion SEMS (110.7 ± 8.6 mmHg) was significantly higher than that of the D-type occlusion SEMS (93.8 ± 11.2 mmHg, p = 0.015); however, the mean bursting pressures causing contrast blowout did not differ between the two types (178.7 ± 11.2 mmHg vs. 176.2 ± 11.8 mmHg, p = 0.715). In conclusion, M- and D-type occlusion SEMSs showed similar efficacy in occlusive properties in the 3D phantom study; however, the M-type was superior in the ex vivo porcine urinary tract model. Further in vivo experimental studies are required to confirm these experimental results.