1

UPDATE ON LASER

LITHOTRIPSY

Joel Teichman MD

University of British Columbia

Vancouver, BC

2

OBJECTIVES

• Mechanisms of laser lithotripsy

• Clinical results

• Limitations of fibers

• Ureteronephroscopy?

PULSE DURATIONJ Endourol 2001; 15: 257

3

SHORT PULSE LASERSLasers Surg Med 1995; 16: 134

PULSED DYE LASERJ Urol 1991; 146: 1228, J Urol 1990; 143: 267

• 504 nm

• Safe

• 64% effective solo

• Effective for dihydrate, struvite

• Ineffective for monohydrate, brushite,

cystine (FREDDY same)

• LEP induces color vision deficits

4

ALEXANDRITE, Q-SWITCHLSM 1997; 20: 433, Urol 1998; 51: 33

• 810-850 nm

• Ultrashort pulse (500 ns)

• High peak power

• No more effective than pulsed dye

• Fiber problems

HOLMIUM:YAG LASER

• 2100 nm

• 250 usec

• Near-infrared spectrum H20 absorption

• Low OH- silica fibers (200 – 1000 um)

5

PULSE DURATION AND

VAPOR BUBBLE DYNAMICSLasers Surg Med 1996; 18: 278

PHOTOTHERMAL

MECHANISMJ Endourol 1999; 13: 181

1 mm150 µµµµs40 us

300 us

400 us

6

PHOTOTHERMAL

MECHANISMJ Endourol 1999; 13: 181

400 us

PHOTOTHERMAL

MECHANISMJ Endourol 1999; 13: 181

0

5

10

15

20

25

30

35

40

45

COM stone loss

sto

ne loss (m

g)

Stone in water

Wet stone in air

Dry stone in air

150 J Ho:YAG

P=0.001

7

BEAM PROFILEJ Endourol 2003; 17: 63

• Fragmentation =

fluence

ENERGY DENSITY J Urol 1998; 160: 471-6

• symmetric craters

• Energy efficient up

to 1 J

• 365 um fiber

8

FRAGMENT SIZEJ Urol 1998; 159: 17-25

• Smaller fragments

• All compositions

RETROPULSIONJ Urol 2003; 169: 881-5

9

PULSE DURATION

Lasers Surg Med 2006; 38: 762

0 100 200 300 400

0.00

0.05

0.10

0.15

0.20

Short pulse

Long pulse

Signal (V)

Time (µµµµsec)

Q0 = 800 mJ

FWHM 120-190 µsec vs. 210-350 µsec

RETROPULSION VS. ENERGYLasers Surg Med 2006; 38: 762

400 600 800 1000 12000

5

10

15

20 Short Pulse

Long Pulse

Retropulsion D

ista

nce (mm)

Pulse Energy (mJ)

273 µµµµm fiber

400 600 800 1000 12000

5

10

15

20 Short Pulse

Long Pulse

Retropulsion D

ista

nce (mm)

Pulse Energy (mJ)

365 µµµµm fiber

400 600 800 1000 12000

5

10

15

20 Short Pulse

Long Pulse

Retropulsion D

ista

nce (mm)

Pulse Energy (mJ)

550 µµµµm fiber

P<0.05

10

ABLATION VS. ENERGYLasers Surg Med 2006; 38: 762

400 600 800 1000 12000.00

0.04

0.08

0.12

0.16

Ablation V

olume (mm

3)

Pulse Energy (mJ)

273 µµµµm

365 µµµµm

550 µµµµm

Short Pulse

400 600 800 1000 12000.00

0.04

0.08

0.12

0.16

Ablation V

olume (mm

3)

Pulse Energy (mJ)

273 µµµµm

365 µµµµm

550 µµµµm

Long Pulse

RETROPULSION NORMALIZED

FOR ABLATION

Lasers Surg Med 2006; 38: 762

400 600 800 1000 12000

50

100

150

200 Short Pulse

Long Pulse

Retropulsion D

ista

nce (mm) / A

blationVolume (mm

3)

Pulse Energy (mJ)

273 µµµµm fiber

400 600 800 1000 12000

50

100

150

200 Short Pulse

Long Pulse

Retropulsion D

ista

nce (mm) / A

blation V

olume (mm

3)

Pulse Energy (mJ)

365 µµµµm fiber

400 600 800 1000 12000

50

100

150

200 Short Pulse

Long Pulse

Retropulsion D

ista

nce (mm) / A

blation V

olume (mm

3)

Pulse Energy (mJ)

550 µµµµm fiber

P<0.05

11

PRESSURELasers Surg Med 2006; 38: 762

0

5

10

15

20

Pulse Duration

Long PulseShort Pulse

Pressure (bar)

0 200 400 600 800 1000

0

10

20Short Pulse

Pre

ssure (bar)

Time (µµµµsec)

0 200 400 600 800 1000

0

10

20

Long Pulse

Pre

ssure (bar)

Time (µµµµsec)

P<0.05

URETERAL STONES

• 94% stone-free J Urol 1997; 158: 1357

• 86% stone-free J Urol 1996; 156: 912

• 90% stone-free UROLOGY 1996; 48: 199

• 92% stone-free BJU 1999; 84: 1

• 84% stone-free > 2 cm J Endourol 2005; 19: 780

• HM-3 J Urol 1997; 158: 1915-21

12

RENAL STONESJ Urol 2002; 167: 31

75

80

85

90

95

100

sto

ne-f

ree %

Distal Ureter

Proximal Ureter

Kidney

LOWER POLE STONESJ Urol 2001; 166: 2072

0

10

20

30

40

50

60

70

80

90

100

sto

ne-f

ree %

PCNL

ESWL

P<0.001

13

LOWER POLE

NEPHROSCOPY• Extend holmium

fiber PRIOR to

ureteroscope

deflection

• Deflect

ureteroscope after

fiber tip is seen

beyond scope

LOWER POLE 2J Urol 2005; 173: 2005-9

• N=78 (67)

• LP stones < 1 cm

• Comparable preop

0102030405060708090

100

OR

time

(min)

stone-

free %

SWL

scope

P=0.01

P=0.82

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ACCESS SHEATHUrol 2003; 61: 713; J Urol 2003; 170: 111; J Urol 2006; 175: 2129

•Decreases OR time

•Increases irrigation

•Decreases RPP

•Protects scope

•Stent!

•54% stone-free

STENT?

• J Urol 2001; 166: 1651

• J Endourol 2002; 16: 9

• J Urol 2002; 167: 1977

• J Urol 2001; 165: 1419

• J Urol 2001; 166: 1252

• J Urol 2003; 169: 1257

• BJU Int 2004; 93: 1032

0

5

10

15

20

25

30

35

40

stented unstented

ER

retu

rn r

ate

%

Access sheath

P<0.05

15

LIGHT TRAVELS STRAIGHT!

• Anecdotes of

ureteroscope #

• Lower pole cases

• Maximal deflection

FIBER DESTRUCTION

TESTINGJ Endourol 2005; 19:1092

• Lumenis

• Sharplan

• InnovaQuartz (IQ)

• Dornier

• Trimedyne

• Laser Peripherals

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LASER FIBERJ Endourol 2004;18:818

LIGHT TRANSMISSIONJ Endourol 2004;18:818

δ

Lens

Laser Beam

m

Acceptance Cone

Laser Fiber

Laser Fiber

Laser Fiber Core (n )

Laser Fiber Cladding (n )2

1

δm

cα

90°−αc

Environment (n )0

17

FIBER DEFLECTIONJ Endourol 2004;18:818

38°

9°

51°

23°

Totally Reflected Ray of Light

(Total Internal Reflection)

Totally Reflected Ray of Light

(Total Internal Reflection)

Incident Rays of Light

Laser Fiber

URETEROSCOPE

DEFLECTION

18

SMA CONNECTOR FAILURE

PROXIMAL FAILURE

• Fiber NA

• Refractive index

• Overfill

δ

Lens

Laser Beam

m

Acceptance Cone

Laser Fiber

19

FIBERS

• Dornier Super 200 failed repeatedly (8 watts)

• Dornier DUR reusable failed at 20th cycle (5

cycles)

• Trimedyne 200 fails with Lumenis

• BS AccuFlex does not couple well with

Lumenis laser

• LP RBLF200 fractured once

• All other fibers tested well

DISPLACE LP STONESJ Urol 2002; 168: 43

• Tipless nitinol baskets, graspers

• Displace into upper pole or RP

• Work with ureteroscope straight

• Avoid fiber issues

• Stone-free 77% in situ vs. 89% displace

• > 1 cm, 29% vs. 100%, p<0.01

20

ERBIUMJ Urol 2001; 165: 876; J Urol 2002; 168: 436

• FEL 2.9 um

• Erbium 2.94 um

• 2-3 x

• Germanium /

sapphire fibers

0

20

40

COM cystine

Er

Ho

P<0.01

CYSTINELSM 2006; 38: 39

Erbium

Holmium

1 x 5 x

21

THULIUMLSM 2005; 37: 53; Appl Opt 2006; 38: 39-45

• 1.94 um

• Soft tissue

• Hard tissue

• Thulium laser

• Thulium fiber laser

• Diode

CONCLUSIONS

• Photothermal mechanism

• Ureteroscopy better and easier

• Ureteroscopy for ureteral stones (renal)

• Renal stones (UP, interpolar, renal

pelvis)– ESWL?

• Lower pole (displace if possible)

• Future advances