1

CAMPUS GROSSHADERN

Laser-Forschungslabor

Laser assisted stone fragmentation

Ronald Sroka

Oulu – Summerschool 2017

ECBO 2015 - Sroka 2/23

Stones

Mechanism

Fibre & Damage

Side Effect Investigations

Clinical Laser

Collateral Damage

Summary

Outline

ECBO 2015 - Sroka 3/23

Urinary Stones

increased expulsion of stone promotors- Calcium- Oxalic acid- Cystine

reduction of stone inhibitors- Citrate- Magnesium

changed acid content- strongly acidic urine (uric acid diathesim)

- strongly alkalin urine (renal illness, RTA)

ECBO 2015 - Sroka 4/23

Urinary Stones

hyperexcretion+

supersaturation

crystallisation

ECBO 2015 - Sroka 5/23

Diagnostic

CTx-rayECBO 2015 - Sroka 6/23

Therapy ESUT Report

57% URS:

intracorporealLithotripsy

PneumaticLithotripsy

70%

Laserlithotripsy24%

Electrohydraulic Lithotripsy

6%

survey of trends and strategies of endourologic stone-therapy

(ESUT Endourological Stone Management Questionnaire) Kauer et al, Eur. Urol. 2005

2

ECBO 2015 - Sroka 7/23

Laser ESWL

SFR:

SFR:

SFR:

SFR:

SFR:

SFR:

50-84%

83-100%

95-100%

45-80%

45-64%

73-100%

Stone-free-rate

ECBO 2015 - Sroka 8/23

Equipment Semirigid URS

- OD 7,5 - 12 Ch

- Workchanel: 5 - 8 Ch

Flexible URS- OD: 6,5 - 7,5 Ch

- Workchanel: 3,6 Ch

- Flexion: → 360°

Endourologic tools- forceps

- dormia

- catheter

treatment options- pneumatic

- ultrasound

- electrohydraulic

- laser

ECBO 2015 - Sroka 9/23

Stones

Mechanism

Fibre & Damage

Side Effect Investigations

Clinical Laser

Collateral Damage

Summary

Outline Disruption - Fragmentation

Irradiance[W/cm²]

Irradiation[J/cm²]

Time [s]

<70°C100°C

>>150°C

<40°C

ECBO 2015 - Sroka 11/23

Dynamic of an vapor bubble

expanding phase

collapsing phasemax

Ho:YAG in watert(sequence) = 1ms

Verdaasdonk et al 2007; Proc SPIE 64350S

ECBO 2015 - Sroka 12/23

Bubble dynamic

Cavitation

Shockwave induced by collapse

oscillation

3

ECBO 2015 - Sroka 13/23

Optic breakthrough (LIB)

Optical breakthrough: 1011 W/cm2

laser induced breakdown (LIB)

- ionisation- Electrons get accelerated by laser field- Ionisation-avalanche (plasma)- Optical penetration decreases significantly (plasmashielding)

ECBO 2015 - Sroka 14/23

Laser pulse in waterVapour bubble Shock wavePressure wave

v(shock) >> v(pressure)

ECBO 2015 - Sroka 15/23

Shock wave front

High pressure high speed

x

p

ECBO 2015 - Sroka 16/23

High energy shockwave

Transmission / Reflexion at boundary to tissue or water

Tension and pressure within the stone structure

Fragmentation

Photomechanic process

ECBO 2015 - Sroka 17/23

Photothermal Ablation

∆t > 100μsP = 106 W/cm2

Photomechanic Ablation

∆t = 1ns-100μsP > 108 W/cm2

Mechanic vs Thermal

ECBO 2015 - Sroka 18/23

Photothermal destruction

Moses effect

Absorption by stone water

Expansion / vaporisationwater jet

destruction

4

ECBO 2015 - Sroka 19/23

Laser parameter0.5 GW / m²

stone properties

IonisationPlasma creating

10-9 s 15.000 K1020 Elektrons / cm³

Stochastic process

Heating of heavy particles due t impulse

10-8 s

Thermal circumference

Of the volume (200 m/s)10-8 - 10-4 s

Shock wave5 %

Shock < 30 %

Secondary shock wave

water - Jet10-4 s

Fragmentation

Cavitation10 %

Stochastic processECBO 2015 - Sroka 20/23

Mechanisms

2-10µs-laser pulse 250-1000µs-laser pulse

photomechanic photothermal

ECBO 2015 - Sroka 21/23

Laser safed operation process at the urology, ed AG Hofstetter Thieme 2003

Ureter Stone

Stone bed afterlaserlithotripsy

stone after 62shock waves(FLPD, 594nm, 150mJ)

Stone after 84shock waves(FLPD, 594nm, 150mJ)

Before laserlithotripsy

ECBO 2015 - Sroka 22/23

Stones

Mechanism

Fibre & Damage

Side Effect Investigations

Clinical Laser

Collateral Damage

Summary

Outline

ECBO 2015 - Sroka 23/23

core diameter 200-600µm

Light emission:

in air and water

Verdaasdonk et al 2007; Proc SPIE 64350S

Fibres

ECBO 2015 - Sroka 24/23

Fibre tip damage

angled side-firing

random process

Verdaasdonk et al 2007; Proc SPIE 64350S

5

ECBO 2015 - Sroka 25/23

Deflection angled fibre tip (45°)

Verdaasdonk et al 2007; Proc SPIE 64350S

Ray-tracingcalculation

Emissionin air

Deformation of bubble3-beam deflection

ECBO 2015 - Sroka 26/23

Fiber burn

Laser type Ep [mJ] Fiber burn off [µm / pulse]

Ho:YAGdcore = 365 µm

500 3,6 ± 0,3800 11,7 ± 0,5

FREDDYdcore = 273 µm

_120 14,1 ± 1,5

_160 25,2 ± 2,0

FLPDdcore = 300 µm

100 9,5 ± 1,3150 16,9 ± 1,7

ECBO 2015 - Sroka 27/23

Verdaasdonk et al 2007; Proc SPIE 64350S

Thermal impact bare fibre tip

Bubble – shock wave Temperature profil

ECBO 2015 - Sroka 28/23Verdaasdonk et al 2007; Proc SPIE 64350S

Thermal impact angled fibre tip (45°)

Bubble – shock wave Temperature profil

ECBO 2015 - Sroka 29/23

Stones

Mechanism

Fibre & Damage

Side Effect Investigations

Clinical Laser

Collateral Damage

Summary

Outline

ECBO 2015 - Sroka 30/23

Schematic diagram of the forces involved in the equation of motion of the pendulum experiment:

F Stokes frictionFback restore forcem mass of the pendulumr radius of the lead balls deflectionL length of pendulumΘ deflection angleηH2O viscosity of water

Repulsion set-up

Experimental set-up, measurements and evaluation were previously described

Sroka R et al. Lasers Med Sci. 2012 May;27(3):637-43

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ECBO 2015 - Sroka 31/23

Stone repulsion - pendulum test

xmax: maximum deflectionv0: start speed

20cm/s = 0,72km/h; 5cm/s = 0,18km/h

Laser type Ep [mJ] xmax [cm] v0 [cm / s]

Ho:YAGdKern = 365 µm

800 0,94 ± 0,38 6,1 ± 2,5

1200 1,61 ± 0,42 10,5 ± 2,7

FREDDYdKern = 273 µm

_120 3,19 ± 0,26 17,0 ± 1,4

_160 3,63 ± 0,29 19,4 ± 1,5

FLPDdKern = 300 µm

100 2,11 ± 0,41 14,2 ± 2,8

150 2,67 ± 0,42 17,9 ± 2,8

ECBO 2015 - Sroka 32/23

Fiber burn back result

Fibre burn back is a stochastic processn(LP) >> n(SP) to destroy fibre

Sroka R et al., World J Urol. 2015 Apr;33(4):479-85.

ECBO 2015 - Sroka 33/23

Repulsion result

max. pendulum deviation

high energy per pulseshort pulse durationlarge fibre core diameter

repulsion decreases

reduced energy per pulsesmaller fibre core diameterlonger pulse duration

Sroka R et al., World J Urol. 2015 Apr;33(4):479-85.

ECBO 2015 - Sroka 34/23

Hand-held and motivated fragmentation showed no sign. differences LP vs SP but for 2J-5Hz

Fragmentation hand-held

Bader MJ et al., World J Urol. 2015 Apr;33(4):471-7.

ECBO 2015 - Sroka 35/23

Scope: Are there differences in puls induced craters?

Fibre position: nearly contact, stepping motor drivenvelocity according to repetition rate

Fibre: fresh polishedLaser parameter: 365µm–10W (20Hz-0.5J, 10Hz-1J, 5Hz-2J)

200µm–10W (5Hz-2J, 10Hz-1J)Laser mode: short pulse vs long pulse

20Hz-0.5J (400µs vs 600µs)

10Hz-1J (475µs vs 1220µs)

5Hz-2J (678µs vs 1500µs)

Evaluation: n=10 holes in BEGOS / group

OCT: TELESTO™ OCT Imaging SystemThorlabs GmbH, Dachau/Munich, Germany

lat. res. 15µm / axial res. 5µmCalculation: topology (depth, diameter, area, volume)Statistic: mean, stddev, 1way Anova

Single Pulse Crater

ECBO 2015 - Sroka 36/23

Single Pulse Crater OCT-evaluation

Sroka R et al., World J Urol. 2015 Apr;33(4):479-85.

7

ECBO 2015 - Sroka 37/23

Single Pulse Crater volume

365µm results trend:depth SP < LParea SP > LP volume SP < LP

Sroka R et al., World J Urol. 2015 Apr;33(4):479-85.

ECBO 2015 - Sroka 38/23

Side effects summary

LongPulse ShortPulse

Fibre Burn Back reduced

Repulsion reduced

Fragmentation hand-held no difference

Fargmentation hands-free no difference

Single Pulse Crater no significance

trends depending on fibre diameter (irradiation)

pulse duration

ECBO 2015 - Sroka 39/23

Recommendation

Fragmentation experiments showed no sign. difference

Single Pulse trends may reflect clinical observation

Recommendation

LongPulse reduced side effectsadditional maneuvres could be reducedeffect on soft tissue may be reducedsmaller fragments could be beneficial

ShortPulse fixed urolithrepulsion effects are minimizedfast fragmentation looks promising

ECBO 2015 - Sroka 40/23

Stones

Mechanism

Fibre & Damage

Side Effect Investigations

Clinical Laser

Collateral Damage

Summary

Outline

ECBO 2015 - Sroka 41/23

Historic list

Laser Excimer FLPD Alexandrit Ti : Saphir Nd : YAG Ho : YAG

Wellenlänge [nm] 308 504 / 594 755 792 1064 2130

Leistung [mJ / Puls]

30 - 60 30 - 150 70 bis 250 10 - 100 500 - 2000

Pulsdauer [µs] 0.04 1 - 2.5 0.1 - 0.5 0.1 - 0.5 0.01 350

Repetitionsrate[Hz]

1 - 40 1 - 10 1 - 10 1 - 10 k. A. 1 - 15

Laser Excimer FLPD Alexandrit Ti : Saphir Nd : YAGFreddy

Ho: YAG

Wavelength [nm]

308 504 / 594 755 792 1064532

2130

energy/pulse[mJ / Puls]

30 - 60 30 - 150 70 bis 250 10 – 100120-160

500 -2000

Pulsduration[µs]

0.04 1 - 2.5 0.1 - 0.5 0.1 - 0.5 0.011-3

350

Repetition rate [Hz]

1 - 40 1 - 10 1 - 10 1 - 10 k. A. 1 - 15

ECBO 2015 - Sroka 42/23

Clinical available today

company name type

Wavelight Auriga Ho:YAG

Dornier Medilas H20 Ho:YAG

WOM Freddy Nd:YAG / KTP

STORZ Calculase Ho:YAG

Baasel Lithognost FLPD

EMS Ho:YAG

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ECBO 2015 - Sroka 43/23

Lasers feedback

Laser type Wavelength Parameter tissue-stone-determination

FreDDYFREquency-Double Dual Pulse

Nd:YAG-Laser

(U100plus – WOM)

532nm plus 1064nm E (puls) = 160 mJ

t(puls) = 1,2 µs

Rep.rate = 1-20 Hz

yes

flashlamp-pmped colouring laser

(FLPD)

(Lithognost - Baasel, Wavelight)

5943nm E (puls) = 60-150 mJ

t(puls) = 2,5 µs

Rep.rate = 1-10 Hz

yes

Ho:YAG

AURIGA – WavelightMedilas H20 – DornierCalculase – STORZ

2100nm E (puls) = 0,3–3 J

t(puls) = 200–600 µs

Rep.rate = 1-25 Hz

no

ECBO 2015 - Sroka 44/23

FREDDY-systemFrequency Doubled Dual pulse Nd:YAG

ECBO 2015 - Sroka 45/23

Feedback -Lithotripsy

t (Feedback) 0,8µsafter 2% total energymax. 5% on tissue

ECBO 2015 - Sroka 46/23

Dormiabasket

Lasergestützte Operationsverfahren in der Urologieed. AG Hofstetter Thieme 2003

Lasercatheter Hofstetter

Central lumenLaserfibre 365µm

Left: Stone in DormiabasketRight: LISL

ECBO 2015 - Sroka 47/23

... depends on the stone composites

... depends on build-up of the stones

Calziumoxalatmonohydrat Calziumoxalatdihydrat Struvit Apatit Bruschit Uric acid (green - brown) Cystin Cholesterol

Efficiency

ECBO 2015 - Sroka 48/23

Stones

Mechanism

Fibre & Damage

Side Effect Investigations

Clinical Laser

Collateral Damage

Summary

Outline

9

ECBO 2015 - Sroka 49/23

aus: Körperwelten (v. Hagen)

Upper Urinary Tract

ECBO 2015 - Sroka 50/23

Instruments

Advantages:• easy handling

• multiple working instruments

• large lumen of the working channel

Disadvantages:• limited flexibility

• limited possibility of inspection areas

Semirigide or rigide Ureterorenoscope

ECBO 2015 - Sroka 51/23

Instruments

Advantage:• High degree of flexibility

(270°/90°)

possible inspection of

lower renal calix

Disadvantage:• complex orientation

• special instruments required

• mechanically sensitive

• handling

Flexible Ureterorenoscopes

ECBO 2015 - Sroka 52/23

Interaction guide-wire

Freddy120mJ, 273µm

distance3mm

FLPD120mJ, 300µm

distance0mm

Ho:YAG1200mJ, 600µm

ECBO 2015 - Sroka 53/23

Interaction kidney-catheter

Freddy120mJ, 273µmdistance: 1mm

Ho:YAG800mJ, 365µmdistance: 1mm

FLPD120mJ, 300µmdistance: 1mm

ECBO 2015 - Sroka 54/23

Interaction 3-handed gripping pillars

Ho:YAG1700mJ

Ho:YAG500mJ

Freddy120mJ

FLPD120mJ

10

ECBO 2015 - Sroka 55/23

Interaction ureter tissue

Ho:YAG, FLPD, Freddydistance: 1-2mm

ECBO 2015 - Sroka 56/23

OrientationHo:YAG

ECBO 2015 - Sroka 57/23

Stones

Mechanism

Fibre & Damage

Side Effect Investigations

Clinical Laser

Collateral Damage

Summary

Outline

ECBO 2015 - Sroka 58/23

Cave ...stone repulsion (splitter, catapulting)

individual choice of E(puls) and Hz

damage on tissue

potential of destruction of equipment

Attention

ECBO 2015 - Sroka 59/23

Summary

LISL-effect depends on ...laser and laser parameters

LISL is ...efficient local stone destruction therapy

(with each laser)

efficient in destruction of equipment, too(positive, as well as, negative in terms of use)

ECBO 2015 - Sroka 60/23

Thank You !!