Nickel-titanium shape memory alloy Memokath 051 ureteral stent for managing long-term ureteral obstruction: 4-year experience

Purpose: We present our 4-year experience with the thermo-expandable shape memory alloy Memokath 051 stent (Engineers and Doctors of Copenhagen, Copenhagen, Denmark) for managing long-term ureteral obstruction. Materials and Methods: We used a nickel-titanium shape memory alloy ureteral stent to treat 28 patients 29 to 86 years old (mean age 59.2). Ureteral obstruction was caused by malignancy in 18 cases and by recurrent benign disease in 10. A total of 37 stents were inserted from November 1996 to November 2000 using general anesthesia. Mean followup was 19.3 months (range 3 to 35). Results: Upper tract decompression was achieved in all cases. Currently 15 stents are functional in 13 patients, while 8 patients died with a total of 13 functioning stents in place. In 7 patients 9 stents were removed for various reasons. There has been no radiological evidence of encrustation to date. No patient has been rehospitalized with stent related sepsis pain or hematuria, resulting in improved quality of life. Conclusions: This stent seems to provide a significant benefit over conventional Double-J (Medical Engineering Corp., New York, New York) and other metallic stents. Its remarkable thermal memory permits removal, a feature that until recently was not available in any other metallic ureteral stent. Durable and complication-free decompression of the upper tract can be achieved with the Memokath 051.