Improving Stone Surgery Efficiency: New Insights from a Kidney Model Study
A new approach to kidney stone removal shows promise for safer and faster procedures
A recent in vitro study explored how a combination of two technologies—a flexible suction ureteral access sheath (FANS) and a foot-controlled irrigation device (Peditrol®)—can improve the efficiency of kidney stone fragment removal during retrograde intrarenal surgery (RIRS), while maintaining safe kidney pressures.
The findings suggest that this combined approach may help surgeons remove stone fragments more quickly without increasing the risk of dangerous pressure build-up inside the kidney.
What the study investigated
Researchers used a synthetic kidney model made from hydrogel, designed to closely mimic the structure and pressure dynamics of a human kidney.
Artificial stone fragments (2–4 mm) were placed inside the model and removed using two different techniques:
Group A (standard method): Continuous gravity irrigation + FANS suction
Group B (new approach): Same setup + intermittent foot-controlled flushing (Peditrol®)
The goal was to compare:
Intrarenal pressure (IRP)
Stone fragment retrieval time
Key findings
1. Kidney pressure remained safe in both methods
No significant difference in intrarenal pressure between the two groups
Mean and peak pressures stayed within safe ranges
This suggests the new method does not increase risk of pressure-related complications
2. Stone removal was significantly faster
Standard method: ~312 seconds
Peditrol-assisted method: ~236 seconds
The addition of intermittent flushing significantly improved retrieval efficiency
3. Safety + efficiency combined
Even though pressure briefly fluctuated during flushing, the overall kidney pressure remained stable and safe. The improved flow likely helped mobilize stone fragments toward the suction sheath more effectively.
Why this matters
Kidney stone surgery (RIRS) has evolved toward “dusting” techniques using lasers, which break stones into tiny fragments. However, not all fragments pass naturally, and some still require removal.
This study highlights a potential improvement:
FANS already helps suction stone dust and fragments
Adding foot-controlled irrigation gives surgeons more control over fluid flow
The combination may reduce the need for basket retrieval tools
It may also shorten surgery time without increasing complication risk
How it works (simplified)
Researchers believe the improvement comes from fluid dynamics:
Continuous suction creates a steady flow pathway
Intermittent flushing briefly increases fluid velocity
This helps “push” or mobilize stone fragments toward the suction channel
The result: faster and more efficient clearance
Study limitations
This was an in vitro phantom (lab) model, not real patients
Human factors like bleeding, anatomy variation, and breathing were not present
A relatively large 12/14 Fr access sheath was used, which may not suit all clinical cases
So while promising, the findings still need confirmation in animal and clinical studies.
Conclusion
The study demonstrates that combining FANS suction technology with intermittent foot-controlled irrigation can:
Improve stone fragment removal efficiency
Maintain safe intrarenal pressure levels
Potentially enhance performance during RIRS procedures
However, further clinical research is required before widespread adoption in real-world surgical practice.