Comparison of efficacy and safety between a segmental thermo-expandable metal alloy spiral stent (Memokath 051) and a self-expandable covered metallic stent (UVENTA) in the management of ureteral obstructions.

Objective: To determine the efficacy and safety of the Memokath 051™ (PNN Medical, Glostrup, Denmark) and UVENTA™ (Taewoong Medical, Seoul, Korea) metal stents, we reviewed our experience with these two metallic ureteral stents for treating benign and malignant ureteral obstructions.

Methods: Twenty-seven patients who received treatment with metallic ureteral stents (Memokath 051, 10 patients; UVENTA, 17 patients) from November 2011 to May 2013 at our institution were identified and analyzed. We conducted a comparative analysis of the causes of obstruction, technical/clinical success rate, cause of failure, and complications.

Results: No difference was observed between the two metallic stents for the causes of benign and malignant ureteral obstructions (P=.073). The Memokath 051 and the UVENTA were inserted successfully in all ureters using a retrograde technique. The mean follow-up was 13.6 months for Memokath 051 and 12 months for UVENTA (P=.244). The clinical success rate of the UVENTA was higher than that of Memokath 051 (82.4% versus 42.9%; P=.031). The causes of failure were obstruction by tumor progression (n=2) and stent migration (n=6) in cases that received Memokath 051 and stent migration (n=1) and obstruction by mucosal hyperplasia (n=2) in UVENTA. The complications caused by Memokath 051 were intermittent flank pain (n=1) and acute pyelonephritis (n=1), whereas those of UVENTA were intermittent flank pain (n=1), gross hematuria (n=1), and acute pyelonephritis (n=1).

Conclusions: The UVENTA achieved a higher clinical success rate than the Memokath 051. Our study demonstrated that the UVENTA is safe and effective in the management of benign and malignant ureteral obstruction. The complications were similar between the two metallic stents.