Suction Access Sheaths for Kidney Stone Surgery

Flexible Active Suction Sheaths (FANSs) are transforming ureteroscopy by improving visibility, reducing pressure, and clearing stone debris in real time. This post explains how they work and why they matter.

The Problem with Traditional Ureteral Access Sheaths

Conventional ureteral access sheaths are rigid. While they help surgeons guide a ureteroscope into the kidney, their inflexibility creates a real challenge: the kidney's internal anatomy is anything but straight. Tight angles around the ureteropelvic junction and access to difficult calyces, particularly the lower pole, have been persistent obstacles.

Rigid sheaths also cannot apply suction at the point of laser lithotripsy, meaning stone dust, debris, and fragments accumulate inside the kidney during treatment. This raises intrarenal pressure, reduces visibility, and slows down the procedure.

Traditional rigid sheaths were like trying to vacuum a room through a straw stuck in the doorway. FANSs bring the suction directly to the source.

What Are FANSs and How Do They Work?

Flexible Active Suction Sheaths (FANSs), sometimes called kidney hoovering devices, represent the next generation of ureteral access technology. Unlike rigid predecessors, FANSs are designed to:

Bend and flex alongside the flexible ureteroscope, navigating even tight renal angles.

Apply continuous active suction directly at the working tip, where the laser is fragmenting stone.

Clear stone dust and debris in real time, maintaining excellent visibility.

Reduce intrarenal pressure by actively removing fluid and fragments rather than allowing buildup.

The result is a cleaner operative field, safer pressure levels within the kidney, and more efficient stone clearance, all without increasing the invasiveness of the procedure.

Expanding the Reach of Ureteroscopy

Before active suction sheaths, the accepted guideline was to use percutaneous nephrolithotomy for stones larger than 2 cm. The rationale was sound: larger stones, when broken up ureteroscopically without suction, risked causing steinstrasse, where fragments block the ureter as they pass.

Active suction changes this calculus. By continuously evacuating fragments during laser lithotripsy, FANSs reduce the steinstrasse risk and make it safer to treat larger stones ureteroscopically. Surgeons can now fragment and remove stones in real time, not just blast them and hope for the best.

Clinical Evidence: FANSs vs. Mini-PCNL

A recent international randomised controlled trial compared flexible ureteroscopy with FANSs against mini-PCNL for the treatment of 2 to 3 cm renal stones. The results were striking:

Flexible ureteroscopy plus FANSs achieved stone-free rates comparable to mini-PCNL.

The ureteroscopic approach offered a less invasive alternative with no skin incision.

Patient recovery was faster and discomfort levels were lower in the FANS group.

Outcomes were strong across a range of stone compositions and locations.

For 2 to 3 cm kidney stones, flexible ureteroscopy with active suction can match mini-PCNL while offering a less invasive path to stone freedom.

Why This Matters for Patients

No skin incision, unlike PCNL, so there is no external surgical wound.

Shorter hospital stays, with most FANS-assisted ureteroscopy performed as a day case.

Faster return to normal activity compared to percutaneous approaches.

Suitable for patients who are not good candidates for open or percutaneous surgery.

Reduced risk of bleeding and infection associated with kidney puncture.

Looking Ahead

The development of FANSs is part of a broader trend in urology towards smarter, less invasive instrumentation. As laser technology, digital miniaturised ureteroscopes, and suction sheaths continue to evolve, the boundary of what can be achieved endoscopically keeps moving.

It is not unreasonable to expect that in the near future, a significant proportion of kidney stones currently treated with PCNL will instead be managed entirely through the ureteroscope, with FANSs playing a central role in making that possible.

Conclusion

Flexible Active Suction Sheaths represent one of the most exciting recent advances in kidney stone surgery. By combining flexibility, precision, and active clearance, FANSs are enabling surgeons to safely treat larger, more complex stones ureteroscopically with outcomes that rival percutaneous surgery and far less impact on the patient.

If you or a patient is facing management of a kidney stone, particularly one over 1.5 cm, it is worth asking your urologist whether ureteroscopy with a FANS device may be the right approach.

Written for urologists, trainees, and informed patients. Always discuss treatment options with a qualified urological specialist.

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