Stone Cone™Nitinol Retrieval Coil Technique

Paul K. Pietrow, MDAssistant Professor of Urology,University of Kansas Medical Center

Introduction The role of endoscopy in the management of ureteral

and renal calculi continues to evolve and expand.

Ureteroscopy provides extensive access to the upper

collecting system, and when combined with holmium

laser energy, facilitates ablation of a vast array of stones.

However, the retropulsion of fragments up the ureter and

into the kidney can extend the required operative time and

can cause colic if all sizeable pieces are not accounted for.

The Stone Cone retrieval coil provides an atraumatic

backboard within the ureteral lumen and can therefore

prevent the retropulsion of calculi. The same device can

also be used to sweep small fragments from the lumen

into a ureteral access sheath or down into the bladder.

(To avoid ureteral avulsion or entrapment, the Stone Cone

device is designed to uncoil as it meets resistance.)

The illustration above demonstrates the stonecone sweeping stone fragments in the ureter.

Technique Steps forusing the Stone Cone™Nitinol Retrieval Coil:

Technique Spotlight

Paul K. Pietrow, MD Assistant Professor of Urology, University of Kansas Medical Center

A gentle retrograde pyelogram is performed at the beginning of the procedure to determine stone

location and possible obstruction. A guidewire is passed beside the stone until it reaches the renal

pelvis and upper calyces.

If the calculus lies above the iliac vessels, a ureteral access sheath is placed over the guidewire under

fluoroscopic visualization.

At this point, I prefer to drive the ureteroscope to the level of the calculus and to pass the Stone Cone

retrieval coil beside it under direct visualization until the stone is between the two black lines on the

Stone Cone sheath. Coaxial traction on the Stone Cone sheath allows the cone to reform. In this way, the

cone can be activated, pulled down to the stone and minor adjustments can be made under endoscopic

rather than fluoroscopic guidance. The endoscope is then backed off of the Stone Cone device.

Next, the ureteroscope is maneuvered beside the Stone Cone device to the level of the calculus and the

holmium laser device is used to destroy the stone. I generally use settings of 0.8 Joules at a rate of 8Hz

in a capacious ureter and lower the settings to 0.6 Joules and 6Hz when the space is snug. As the stone

is painted with laser energy, the Stone Cone retrieval coil sometimes requires minor adjustments to keep

the stone and the cone within the center of the lumen.

Once the calculus has been sufficiently destroyed, residual fragments are pulled down through the ureteral

access sheath under direct endoscopic guidance using the Stone Cone retrieval coil. Significant resistance

will cause the cone to uncoil. While small amounts of uncoiling are common, excessive uncoiling implies

that there is a significant fragment that requires further laser ablation prior to removal. In this scenario,

the Stone Cone sheath is re-deployed; the device is advanced beyond the stone and then reactivated. The

fragment is further lasered before attempts are made to resume sweeping.

After all fragments have been cleared, the ureter is carefully inspected with the ureteroscope. Concurrent

renal calculi can be treated as necessary. The use of a ureteral stent is left to the discretion of the surgeon.

Technique Spotlight

Helpful Tips

1 How to address a failure to completely entrap the calculus: This is best avoided by placing the Stone

ConeT'" retrieval coil past the stone under direct endoscopic guidance.

2 How to address complete uncoiling ofthe Stone Cone device: This occurs when a sizeable fragment

becomes lodged during sweeping. At this point, it is best to deactivate the Stone Cone coil by te-deploying

the sheath, then advancing the tip beyond the calculus, reactivating the coil and continuing to laser the

stone before attempting to clear the ureteral lumen.

3 How to address a clogged access sheath: The ureteral access sheath can occasionally become gritty

and can grab at the ureteroscope as stone dust and small particles flush their way back down. This is com­

pounded by the crowding of the access wire, Stone Cone device and ureteroscope within a tight lumen.

I try to avoid this by using a mid-size access sheath (NavigatorT

" Ureteral Access Sheath 13/15F). Placing the

safety wire outside of the access sheath helps clear space, but requires the use of an extra wire at the start

of the procedure.

Stone Cone NitinoL RetrievaL Coil Ordering InformationProduct Code

M0063903100

M0063903200

Description

Stone Cone Nitinol Urological Retrieval Coil 3.0Fr, 7mm Coil (Each)

Stone Cone Nitinol Urological Retrieval Coil 3.0Fr, 10mm'Coil (Each)

Navigator UreteraL Access Sheath Ordering InformationProduct Code Size Packaged

M0062502000 11/13Fr x 28 em Unit

M0062502011 11/13Frx28em 5-Paek

M0062502020 11/13Fr x 36 em Unit

M0062502031 11/13Fr x 36 em 5-Paek

M0062502040 11/13Fr x 46 em Unit

M0062502051 11/13Frx46em 5-Paek

M0062502060 13/15Fr x 28 em Unit

M0062502071 13/15Fr x 28 em 5-Paek

M0062502080 13/15Fr x 36 em Unit

M0062502091 13/15Fr x 36 em 5-Paek

M0062502100 13/15Fr x 46 em Unit

M0062502111 13/15Fr x 46 em 5-Paek

BostonSCIentIfic

Delivering what's next:"

Boston Scientific CorporationOne Boston Scientific PlaceNatick, MA 01760www.bostonscientific.com/urology

Ordering Information888.272.1001

Caution: Federal law (U.S.A.) restricts this device to sale. distribution and use by or on the order of a physician. Refer to theDirections for Use provided with this product for complete instructions, warnings, and precautions prior to using this product.

Copyright © 2004 by Boston Scientific Corporationor its affiliates. All rights reserved.

DVU1210 5M 6/04-6/06