In endourology, defining ‘DUST’ and optimising its management is vital for improving stone-free rates (SFR) and reducing complications. Residual fragments, even those ≤4mm, can act as a nidus for infection, obstruction, and recurrence. Studies have shown that 30% of patients with small residual fragments required re-intervention within three years. Therefore, fragment clearance is clinically relevant, challenging the notion of ‘clinically insignificant residual fragments’. Dusting – producing fine stone particles during laser lithotripsy – is preferred over fragmenting large pieces, as it reduces the need for basket extraction. However, dust can accumulate in renal cavities, potentially obstructing the ureter, particularly in high-risk patients. Consequently, aspiration and removal of stone dust have become a key focus in ureteroscopy (URS). Despite its importance, ‘DUST’ lacks a standard definition. The Tenon group proposed criteria based on floating ability, sedimentation time, and aspiration feasibility, identifying 250μm as a practical cut-off. However, real-time measurement of particle size during surgery is unreliable due to fluid turbidity, magnification changes, and subjective estimation. Thus, a functional definition, focused on technique rather than fragment size, is more clinically applicable. Producing DUST safely requires careful laser setting selection. While high-power lasers like Ho:YAG and thulium fibre laser (TFL) are effective, excessive energy and temperature can damage tissue. Recent recommendations favour low-frequency, low-power settings for ureteric stones and higher settings for renal stones. TFL offers finer dusting and less retropulsion than Ho:YAG, with smaller fibres (150–270μm) improving flexibility and access. Removal strategies, including suction-enabled ureteral access sheaths (S-UAS), dual-lumen catheters, and the DISS system, show promise, but evidence remains limited. Technological improvements, such as ureteroscopes with dual working channels, may enhance dust removal. Ultimately, consistent terminology, standardised laser settings, and validated dust evacuation techniques are needed to optimise outcomes and reduce recurrence in stone disease.
Why defining and managing DUST matters in endourology
Reviewed by Asif H Ansari
Stone dust in endourology: a systematic review of its definition, management, and clinical impact.
