Current status of metal stents for managing malignant ureteric obstruction.

Obstruction of the ureters caused by extrinsic compression from a primary tumour or retroperitoneal lymph node masses is not unusual in the course of advanced pelvic malignancies. Most of the cases are of gynaecological or gastrointestinal origin, and the situation can be aggravated by peri-ureteric fibrosis, a long-term adverse event of previous chemotherapy or radiotherapy. Undoubtedly upper urinary tract decompression and maintenance of ureteric patency, even as a palliative measure, is important in managing these patients. Options for upper tract decompression include percutaneous nephrostomy, retrograde stenting and open urinary diversion. Plastic stents have long been used for managing malignant ureteric obstruction, but their overall success remains limited. Plastic stents often fail to be placed correctly, require regular exchange, and are faced with a high incidence of encrustation and migration. For these reasons plastic stents have been unsuccessful for long-term maintenance of ureteric patency. To overcome these limitations metal stents were introduced and recently developed in an effort to ensure better long-term patency of the obstructed ureter, fewer hospital admissions for stent change and better overall quality of life. In the present review the clinical applications of different types of metal stents are discussed, with a specific focus on the latest advances and the future options for managing malignant ureteric obstruction.