Flexible Ureteroscopy for Renal Stones < 20 mm with Low-Power Holmium Laser: Is Basket Extraction still Needed or Is Dusting Enough? A Prospective Study with CT-Based Outcome Assessment

Abstract

Objective:

This study compared the stone-free rate (SFR) and complications of two holmium laser lithotripsy techniques—active fragment extraction (FRAG) and dusting (DUST)—during flexible ureteroscopy (FURS) for renal stones using noncontrast computed tomography (NCCT).

Materials and Methods:

A total of 100 patients with renal stones (5–20 mm) undergoing FURS were randomized into FRAG and DUST groups. All surgical parameters, except lithotripsy strategy, were standardized, and ureteral access sheaths were used. The primary outcome was SFR at 90 days, defined as residual fragments ≤2 mm (Grade A + B) on NCCT. Secondary outcomes included the influence of stone volume, density, and complication rates.

Results:

Ninety-three patients completed follow-up (FRAG: 45; DUST: 48). Baseline demographics and stone parameters (diameter, density, volume, location) were similar. Mean stone size (FRAG: 13.9 ± 5.2 mm vs DUST: 13.0 ± 4.7 mm, p = 0.378) and density (FRAG: 999.7 ± 267.6 Hounsfield unit [HU] vs DUST: 1,111.8 ± 249.1 HU, p = 0.044) were comparable. SFRs were 66.7% (FRAG) and 68.8% (DUST) (p = 0.751). Multivariate analysis identified higher body mass index as a predictor of improved SFR (odds ratio 1.17, p = 0.022), whereas stone volume (p = 0.179) and density (p = 0.884) had no significant impact. Operative time, complications, and ancillary procedure rates were comparable.

Conclusions:

Both techniques achieved similar SFRs, with no significant influence from stone volume or density. Postoperative complications and ancillary procedures were comparable. These findings suggest either method is effective, with technique selection based on surgeon preference.