The purpose of this study is to evaluate the safety and efficacy of the Memokath 051 ureteral stent as a long-term temporary and minimally invasive means of providing ureteral drainage in the setting of malignant extrinsic ureteral obstruction secondary to inoperable abdominal or pelvic malignancies. Up to 15 adults who have extrinsic ureteral obstruction secondary to an inoperable abdominal or pelvic malignancy and need ureteral stent drainage will undergo outpatient placement of the ureteral stent. Ongoing monitoring will continue for as long as the stent is in place.

The Memokath 051 ureteral stent is a device designed to provide long-term temporary ureteral drainage in the setting of extrinsic ureteral obstruction secondary to inoperable pelvic and abdominal malignancies or secondary to changes caused by surgery, chemotherapy, or radiation for pelvic and/or abdominal malignancies. The management of malignant extrinsic ureteral obstruction secondary to inoperable neoplastic disease of the abdomen or pelvis is a common urologic problem, and has important implications for a patient's quality as well as quantity of life, which has been estimated to generally range between 6.5 to 23 months in this population. Currently, extrinsic ureteral obstructions are usually managed with double-J ureteral stents, placed either cystoscopically, or antegrade via a percutaneous nephrostomy tube. Double-J stents are prone to encrustation and obstruction over time, necessitating stent exchange under general anesthesia every 3 to 4 months. These repeat surgical procedures under general anesthesia carry subsequent risks of infection, drug reactions, and iatrogenic injury, leading to degradation in the quality of life of these patients who often have a year or less to live. To circumvent these disadvantages, the nickel-titanium Memokath 051 ureteral stent was developed to provide a means of minimally invasive long-term temporary ureteral drainage.

This is a prospective non-randomized clinical study to evaluate the efficacy of the Memokath 051 ureteral stent in managing extrinsic malignant ureteral obstruction secondary to an inoperable abdominal or pelvic malignancy or secondary to changes caused by surgery, chemotherapy, or radiation for pelvic and/or abdominal malignancies. Enrollment of study subjects will take place over a period of two to three years for to a total of 15 patients.

A control group 10 patients with extrinsic ureteral obstruction secondary to an inoperable pelvic or abdominal malignancy or secondary to changes caused by surgery, chemotherapy, or radiation for pelvic and/or abdominal malignancies and treated by other urologic staff surgeons in a standard fashion with retrogradely placed double-J stents will also be followed every 3 to 4 months.

Inclusion Criteria:

1. Presence of extrinsic ureteral obstruction

   1. secondary to inoperable pelvic or abdominal malignancy or
   2. secondary to changes caused by surgery, chemotherapy, or radiation for pelvic and/or abdominal malignancies who have had >2 standard double J stent exchanges with no prospect of being stent-free

2. Life expectancy greater than 4 months

3. Adult patient (18 years of age or older)

4. Preoperative medical examination clearing the patient for general anesthesia

5. No active urinary tract infection by urinalysis and urine culture.

Exclusion Criteria:

1. Ureteral obstruction of a benign or intrinsic etiology
2. Lower urinary tract abnormality precluding cystoscopic stent placement
3. Patients with a solitary kidney
4. Patients not willing or unable to receive their post-operative follow-up at the Mayo Clinic in Rochester, Minnesota
5. Pregnant female patient.

Low number of subjects in each cohort.