Presented by: John Hayes
Department of Urology. The James Cook University Hospital.

Introduction

Memokath 051 (MMK) is a thermo-expandable nickel-titanium alloy stent used in the management of ureteric obstruction. The proposed advantages of MMK over the traditional double-J stent include the avoidance of repeated stent changes, reduced irritative bladder symptoms and potential longterm cost savings. The National Institute for Health and Care Excellence (NICE) has recently recommended its use in selected cases. In this series we evaluate the outcomes of MMK in double-J stent dependent patients.

Materials

A retrospective analysis of a prospectively maintained database of MMK insertions at a single unit between February 2020 and May 2023 was conducted. Inclusion criteria comprised patients that were (1) stent dependant (2) had an anticipated life expectancy of >1 year and (3) were unsuitable for reconstructive procedures. Patients were followed up for stent position and patency with biochemical and radiological investigations. Outcome measures included stent function, migration rates and adverse events. 

Results

,

Forty-nine consecutive MMKs were inserted in 34 patients (20 female and 14 male). This included 33 unilateral and 8 bilateral stent insertions. 20 patients had a benign and 14 an underlying malignant aetiology. Prior to MMK insertion, patients were dependent on their double-J stent(s) for a median of 33 months (4-180). The median follow up following MMK insertion was 32 months (6-44). 12-, 24- and 36-month stent function rates were 60%, 56% and 56% respectively. There were 11 stent migrations, 7 blockages, 2 encrustations, 3 episodes of urosepsis and 1 ureteric perforation.

Conclusion

Our case series would suggest that MMK 051 has a role in select patients with refractory ureteric obstruction. The rate of stent migration is particularly high within the first year of insertion. Longer-term follow up data are required including more evidence in relation to patient-reported outcomes. We await the results of the MinUS study; specifically designed to investigate quality-of-life outcomes of MMK versus double-J stent. 

Funding

None

Co-Authors

Parag Sonawane,
The James Cook University Hospital

Kalpesh Parmar,
The James Cook University Hospital

Chandrasekharan Badrakumar,
The James Cook University Hospital