Educational content only. This article is not medical advice or an instruction for clinical use.
Progress in fragmentation does not end the problem
Flexible ureteroscopy and modern laser systems have expanded the options for treating urinary stones. Nevertheless, the final state after fragmentation can include dust and small residual fragments. The ability to create smaller particles should not be confused with guaranteed complete stone clearance. Clinical follow-up and the significance of residual material depend on factors such as fragment size, composition and patient context.
Why residual fragments matter
Guidelines recognise that residual fragments may be associated with subsequent events or further intervention, while some fragments pass without incident. Their clinical importance is not uniform. This is precisely why technology developers should avoid selecting a single convenient endpoint as proof of value: retrieval rate, device usability, residual burden, procedure time and adverse events answer different questions.
Existing approaches have trade-offs
Baskets capture selected discrete fragments but occupy working-channel space and involve repeated manoeuvres. Dusting strategies may rely on later passage of fine particles. Irrigation and suction arrangements can influence fluid and debris movement, while the safe balance of pressure and visibility remains important. No one approach removes the need for procedure-specific judgement.
What a new retrieval technology would need to prove
An investigational approach intended to gather small fragments would need to demonstrate that it can be delivered through existing instruments, interact predictably with the operative environment, retain material during extraction, and be removed without unacceptable tissue or device-related risk. Bench performance is only an early part of that evidence. Biocompatibility, stability, sterility, usability, preclinical evaluation and any required clinical investigation must follow the relevant development pathway.
An engineering challenge, not a product promise
TORSH is exploring a biomaterial-based concept in this area. It remains investigational and is not available for clinical use. We view residual-fragment management as an example of the need for close dialogue between surgical teams, biomaterials researchers and device engineers—especially when technical feasibility must eventually meet clinical and regulatory standards.
Editorial reference
EAU 2026 Urolithiasis guidance on residual fragments [C1].