The primary aim of the present systematic review and meta-analysis is to determine the technical feasibility and safety of tandem ureteric stent insertion, and the failure rate of tandem stents in relieving malignant ureteric obstruction.

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) Statement. The primary study outcome was the rate of tandem stent failure and the time to failure. Failure was defined as malignant ureteral obstruction that was refractory to tandem stenting, necessitating alternative methods of drainage. Secondary outcomes included technical success, rate of adverse events, overall survival, and duration of stent patency.

The search identified 10 studies for inclusion. A total of 533 patients underwent tandem ureteric stenting for malignant ureteric obstruction. The pooled proportion of stent failure during the follow up period was 18.90% (95% CI, 12.39% – 27.73%, I2 = 66.3%) (Figure 1a). The pooled mean time to stent failure was 13.25 months (95% CI, 4.30 – 22.20 months, I2 = 98.6%) (Figure 1b). The pooled proportion of patients that died during the follow up period of included studies was 49.72% (95% CI, 34.98% – 64.52%, I2 = 86.6%), with a pooled mean survival time of 11.42 months (95% CI, 7.51 – 15.3 months, I2 = 90.7%). The pooled proportion of successful tandem ureteric stent insertions was 96.44% (95% CI, 93.40% – 98.11%, I2 = 0%) (Figure 2). Of these reported adverse events, 8.18% (95% CI 5.63% – 11.74%, I2 = 67.8%) were Clavien-Dindo grade 1 events, 19.50% (95% CI 15.51% – 24.22%, I2 = 61.5%) were Clavien-Dindo grade 2 events, and 4.72% (95% CI 2.86% – 7.68%, I2 = 0%) were Clavien-Dindo grade 3 events. There were no reported grade 4 or grade 5 events.

Our systematic review and meta-analysis suggests that tandem ureteric stenting in patients with malignant ureteral obstruction is a technically feasible procedure that can be performed to de-obstruct the involved renal unit with improved failure rates compared to single ureteric stent insertion.