[Indwelling of Full-Length Metallic Ureteral Stents as an Initial Treatment for Patients with Untreated Malignant Ureteral Obstruction].

To examine the efficacy and safety of a full-length metallic ureteral stent (MS), Resonance®, we retrospectively evaluated 16 cases (22 ureteral units) with indwelling MS as the initial treatment for patients with untreated malignant ureteral obstruction (MUO). All patients had undergone MS insertion by the retrograde approach without cystoscopy, with indirect stent placement under fluoroscopy, as a new method that can be performed even if the number of medical staff is one less than that required. Both serum creatinine and estimated glomerular filtration rate values in all cases improved significantly (p<0. 001). Moreover, MS failure occurred in only one patient and the stent patency rate was 93.8%. Stent-related complications were observed in four patients. Two patients experienced stent dislodgement, and one each had fever and acute pyelonephritis, although none of the complications were life-threatening. After the introduction of MS in our hospital, the rate of percutaneous nephrostomy in MUO patients excluding those not suited for indwelling MS, clearly decreased from 80% to 20%. This is the first report on the clinical evaluation of indwelling MS as the initial treatment of MUO in Japan, and this report indicates that MS is a very useful choice in terms of effectiveness, safety, medical cost, and reduction in the workload of medical staff. We believe that the indwelling MS will become a standard initial treatment for patients with untreated MUO in the future.