Urologists at Work

USE OF THE HOLMIUM:YAG LASER FOR THE IMPACTED STONEBASKET

JOEL M. H. TEICHMAN AND ANGELA D. KAMERERFrom the Division of Urology, University of Texas Health Science Center, San Antonio, Texas

ABSTRACT

Purpose: During ureteroscopic basketing of ureteral calculi a stone may become engaged in thebasket and the basket impacted in the ureter. We describe an endoscopic technique of managingthe impacted basket and stone.

Materials and Methods: The ureteroscope is back loaded off of the basket, and passed into theureter beside the basket and stone. The holmium:YAG laser is used to irradiate a basket wire,fracturing the wire and releasing the stone. The basket is removed and the stone managed byholmium:YAG lithotripsy.

Results: We successfully treated 3 consecutive patients with this technique. No injuries wereobserved.

Conclusions: The holmium:YAG laser may be used to free an impacted stone basket containinga ureteral calculus.

KEY WORDS: ureter; ureteral calculi; ureteroscopy; lithotripsy, laser; intraoperative complications

Ureteroscopy is often performed for ureteral calculi. Whenfeasible, basketing is considered to be the most rapid meansof removing a ureteral stone.1 A potential complication iswhen the basket engages the calculus but the basket andstone cannot be removed from the ureter. Certain simplemaneuvers may solve the problem, such as opening the bas-ket to allow the stone to disengage, and disassembling thebasket hand piece and back loading the ureteroscope off ofthe basket in an attempt to release the stone. We describe aholmium:YAG laser technique to use when these simple ma-neuvers have failed.

MATERIALS AND METHODS

The ureteroscope is passed back into the ureter beside thebasket and entrapped stone. The holmium:YAG laser with a365 mm. optical fiber is positioned in contact with a basketwire. The laser is fired, applying 0.6 J. at 6 Hz. The bas-ket wire fractures, releasing the basket tension, and thestone disengages from the basket. The basket may then bewithdrawn easily and removed from the ureter. The calculusmay be managed by holmium:YAG lithotripsy without thebasket in the ureter.

RESULTS

We successfully treated 3 consecutive patients with animpacted stone basket. In all 3 cases the ureteral orifice wasballoon dilated at the outset of the procedure. Plain x-ray ofthe kidneys, ureters and bladder showed a stone size of 6 to7 mm. All calculi were in the distal ureter and were placed inthe basket without difficulty. A 3Fr tipless nitinol basket wasused in 2 cases and a 3Fr tipped steel wire basket in 1. Initialattempts to withdraw the basket were unsuccessful and at-tempts to disengage the stone from the basket or dissemblethe basket hand piece did not release the stone.

Applying a holmium:YAG laser successfully fractured the

basket rapidly and the stone was immediately released. Noureteral injury occurred due to reflected energy or with-drawal of the fractured basket. All 3 stones were successfullyfragmented by holmium:YAG lithotripsy and the fragmentswere removed with another basket. A Double-J* ureteralstent was placed with dangle strings exiting the urethra.Stents were removed at an outpatient clinic followup visitwithin 1 week after the procedure.

DISCUSSION

With a long pulse duration of 250 microseconds the holmi-um:YAG laser exerts a predominantly thermal effect.2 Inci-dental thermal fracture of accidentally irradiated guide wireshas been reported.3, 4 In an experimental study thermal dam-age to guide wires was predictable based on the irradiationangle and separation distance, consistent with laser physics.5

All wire compositions were susceptible to thermal damage incontact mode at an energy setting of 0.5 J. or less.

Based on our limited series we observed that the holmium:YAG laser fractured the basket and permitted rapid stonerelease and safe basket withdrawal. Holmium:YAG irradia-tion of a basket has been previously described by Segura, whobasketed a stone to stabilize it for holmium:YAG lithotripsy.6

After melting 1 wire he deliberately melted the remainingwires to divide the basket into 2 pieces, which were extractedfrom the ureter with endoscopic forceps. Based on our expe-rience it seems unnecessary to divide the basket into 2 pieces.After 1 wire fractures the basket collapses and is removedunder endoscopic guidance.

Alternatively the entrapped calculus may be irradiated inthe basket and debulked until it falls out or the stone andbasket collapse to a smaller size that may be withdrawn.7

This latter strategy may be particularly useful when thereare 2 ureteroscopic working ports. However, it is possiblethat the basket may be accidentally irradiated, resulting in

Accepted for publication June 9, 2000. * Medical Engineering Corp., New York, New York.

0022-5347/00/1645-1602/0THE JOURNAL OF UROLOGY® Vol. 164, 1602–1603, November 2000Copyright © 2000 by AMERICAN UROLOGICAL ASSOCIATION, INC.® Printed in U.S.A.

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basket fracture. Thus, a dedicated attempt to fracturethe basket initially would rapidly resolve the problem. Byfracturing the basket and removing it at the outset only theresidual calculus must be managed, rather than the stoneand basket.6

A limitation of our strategy is that we have experience withonly 3 cases and 2 basket compositions. Although basketdesign and materials differ, all baskets break with holmium:YAG irradiation at modest settings.8 Tipless baskets breakwith less distortion than tipped baskets. Tipped baskets tendto break with the broken distal wire protruding outward, sothat the basket should be observed carefully as it is removedto avoid accidental ureteral laceration. If the protruding bas-ket wire causes a risk of ureteral injury, the other wiresshould be irradiated until the basket collapses more com-pletely or is divided into 2 pieces.6 In our case of a tippedmetal basket the broken basket wire protruded. However,since the basket collapsed, outward protrusion was minimaland the basket was removed under endoscopic guidance.

Additional strategies may be used for impacted stone bas-kets. The entrapped basket and stone may be left in theureter and extracorporeal shock wave lithotripsy performed.After successful fragmentation the basket should collapse,facilitating removal. This option may be impractical when ashock wave lithotriptor is not immediately available or theentrapped basket and calculus are obscured by the bonypelvis. When a holmium:YAG laser is not available, a uret-eroscope may be passed beside the entrapped basket andanother intracorporeal lithotrite used to fragment the stone,such as a pulsed dye laser, or electrohydraulic, pneumatic or

ultrasonic lithotriptor. When the stone is small enough forthe basket to collapse, the basket and residual stone may beremoved. Furthermore, open ureterolithotomy and basketremoval may be considered when endoscopic options fail. Inconclusion, when a stone is engaged in a basket and thebasket cannot be removed from the ureter, a holmium:YAGlaser may be applied to fracture the basket and proceed withendoscopic lithotripsy

REFERENCES

1. Netto, N. R., Jr., de Almeida Claro, J., Esteves, S. C. et al:Ureteroscopic stone removal in the distal ureter. Why change?J Urol, 157: 2081, 1997

2. Vassar, G. J., Chan, K. F., Teichman, J. M. et al: Holmium:YAGlithotripsy: photothermal mechanism. J Endourol, 13: 181,1999

3. Freiha, G. S., King, D. H. and Teichman, J. M.: Holmium:YAGlaser damage to ureteral guidewire. J Endourol, 11: 173, 1997

4. Grasso, M.: Experience with the holmium laser as an endoscopiclithotrite. Urology, 48: 199, 1996

5. Freiha, G. S., Glickman, R. D. and Teichman, J. M.: Holmium:YAG laser-induced damage to guidewires: experimental study.J Endourol, 11: 331, 1997

6. Segura, J. W.: Intracorporeal lithotripsy. AUA Update Series,vol. 18, lesson 9, pp. 66–71, 1999

7. Low, R. K. and George, D.: Removal of the entrapped basketedureteral calculus: a novel technique. J Urol, 163: 1863, 2000

8. Gallentine, M. L. and Harmon, W. J.: The broken stone basket:configuration and technique for easy removal. J Urol, suppl.,163: 339, abstract 1504, 2000

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