A Prospective Randomized Comparison of a Covered Metallic Ureteral Stent and a Double-J Stent for Malignant Ureteral Obstruction

Abstract

Objective: To compare the safety and efficacy between a covered metallic ureteral stent (CMS) and a double-J ureteral stent (DJS) for the treatment of a malignant ureteral obstruction (MUO).

Materials and methods: Nineteen patients (seven men and 12 women; mean age, 53.4 years) were randomly assigned to the CMS (n = 10) or DJS (n = 9) group. The following were compared between the two groups: technical success, i.e., successful stent placement into desired locations; stent malfunction; stent patency, i.e., no obstruction and no additional intervention; complications; and patient survival.

Results: The technical success rate was 100% in all 10 and 12 ureteral units in the CMS and DJS groups, respectively. During the mean follow-up period of 253.9 days (range, 63-655 days), stent malfunction was observed in 40.0% (4/10) and 66.7% (8/12) in the CMS and DJS groups, respectively. In the per-ureteral analysis, the median patency time was 239.0 days and 80.0 days in the CMS and DJS groups, respectively. The CMS group yielded higher patency rates compared with the DJS group at three months (90% vs. 35%) and at six months (57% vs. 21%). The overall patency rates were significantly higher in the CMS group (p = 0.041). Complications included the migration of two metallic stents in one patient in the CMS group, which were removed in a retrograde manner. The two patient groups did not differ significantly regarding their overall survival rates (p = 0.286).

Conclusion: Covered metallic ureteral stent may be effective for MUO.

Keywords: Covered ureter stent; Double-J ureter stent; Metallic ureter stent; Random; Study; Trial; Ureter obstruction; Ureter stent.

Fig. 1. Structure of silicone-covered, self-expandable, metallic stent (Urexel, S&G Biotech).

A. Both ends are fully covered with silicone membrane, and distally tapered shape is shown with 1-mm difference in diameter between proximal and distal ends. B. Comparison of Urexel metallic ureteral stent and DJS. DJS = double-J ureteral stent

Fig. 2. 55-year-old, male patient with advanced gastric cancer.

A. Enhanced axial CT image shows hydronephrosis of left kidney (arrow) that was caused by periureteric metastasis. B. Antegrade pyelogram via percutaneous nephrostomy tube shows diffuse, long-segmental ureteric strictures (arrows) from proximal- to mid-ureter. C. Antegrade pyelogram immediately following metallic ureteral stents placement shows good flow of contrast medium through metallic ureteral stents into urinary bladder. D. Follow-up enhanced CT image obtained one month after metallic ureteral stents placement shows complete resolution of hydronephrosis of left kidney (arrow). CT = computed tomography

Fig. 3. Kaplan-Meier curve of primary patency rates of both stent groups.

Overall patency rates were significantly higher in CMS group compared with DJS group (log-rank test, p = 0.041). CMS = covered metallic ureteral stent

Fig. 4. Kaplan-Meier curve of survival rates of both stent groups.

Two groups did not differ significantly regarding overall survival rates (log-rank test, p = 0.286).