Spontaneous Stone Passage Rates of Ureteric Stones After Stenting for Acute Renal Colic: A Systematic Review

Background/Objectives: Renal colic poses a significant burden on patients and healthcare systems. Negative ureteroscopy in the setting of stented patients is reported at up to 14%, resulting in unnecessary surgeries and inefficiencies. While ureteral stents have demonstrated efficacy in relieving obstruction, their exact effect on spontaneous stone passage (SSP) is unclear. Hence, a systematic evaluation of the literature was performed to identify the impact of ureteral stents on spontaneous stone passage rates. Methods: A systematic search was conducted in MEDLINE, Embase, and PubMed (January 1989–February 2025) to identify studies investigating indwelling ureteric stents and SSP. Two independent reviewers screened the abstracts and full texts, with a third resolving conflicts. Quality assessment was conducted using The Risk Of Bias In Non-randomized Studies—of Interventions (ROBINS-I) and Cochrane Risk of Bias 2 (RoB-2) tools. Results: A total of 2437 patients in 14 studies investigating SSP in stented patients were included. One included study was a randomised controlled trial, but the rest were observational (n = 13). Three studies compared stented and control groups, whereas 11 studies only investigated patients with stents. Mean/median overall stone sizes ranged from 4.7 to 7.8 mm in diameter. Overall, SSP rates with stents varied significantly, ranging from 1.7 to 42.3%, in the setting of variable stone size, location, duration of follow-up, and method of stone passage detection. When comparing stented and non-stented patients, two studies demonstrated impaired SSP rates in stented patients (13.9% vs. 26.8% and 14% vs. 20%), but only one of these differences was statistically significant. Three studies comparing patients with retrograde ureteral stents and nephrostomies found increased SSP rates in nephrostomy cohorts (p < 0.001). Conclusions: Stone passage rates with stents vary widely due to heterogeneity in study design, patient characteristics, and follow-up. Some studies suggest that stents may impair passage; however, evidence remains inconclusive due to the limited availability of high-quality comparative data. This study underscores the need for larger prospective trials to clarify the actual impact of stenting on stone passage.