Multicenter experience with metallic ureteral stents for malignant and chronic benign ureteral obstruction

Background and Purpose: A new coil-based metallic ureteral stent offers greater radial strength with longer indwelling time compared with plastic stents. This multicenter retrospective study reviews the clinical experience with this stent for malignant or benign chronic ureteral obstruction. Patients and Methods: Patients had stent placement in a retrograde fashion. We analyzed preplacement and postplacement renal imaging to determine degree of hydronephrosis. Stent encrustation was determined by either visual inspection at the time of stent change or plain abdominal radiography. Preoperative and follow-up serum creatinine values were compared for each patient. Results: A total of 76 stents in 59 renal units (40 patients) were successfully placed. Creatinine value follow-up on 54 renal units showed 20 (37%) units to have stable, 15 (28%) improved, and 19 (35%) with worsening values. No stent showed encrustation on plain radiography despite it being seen on two during direct visualization. Three stents needed operative removal with either percutaneous nephrolithotomy or cystolitholapaxy. Fifteen of 41 (37%) metallic stents placed because of an obstructed plastic stent also became obstructed. At last follow-up, 6 of 40 patients were kept from nephrostomy tubes because of the metallic stent. Conclusions: Metallic stents are a viable alternative to nephrostomy tubes in patients in whom conventional stents fail because of malignant obstruction, but patients need to be followed closely. Stent encrustation that resulted in retained stents was poorly visualized on plain radiography. Patients still remain at risk for obstruction, urinary tract infections, and lower urinary tract symptoms from the metallic stent.