effect of modification of shock-wave delivery on stone fragmentation talic rf & rabah dm college...
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Effect of modification of Effect of modification of shock-wave delivery on stone shock-wave delivery on stone
fragmentationfragmentation
Talic RF & Rabah DMTalic RF & Rabah DM
College of Medicine & king Khalid university hospitalCollege of Medicine & king Khalid university hospitalKing Saud UniversityKing Saud UniversityRiyadh, Saudi ArabiaRiyadh, Saudi Arabia
First generation LithotriptorFirst generation Lithotriptor
High success rateHigh success rate
Minimally invasiveMinimally invasive
Second & 3Second & 3rdrd generation lithotriptors generation lithotriptors
User convenienceUser convenience Reduced anesthesia requirmentsReduced anesthesia requirments Multi-functionalityMulti-functionality Results?Results?
Recent publications evaluating Recent publications evaluating different SWL of renal calculidifferent SWL of renal calculi
StudyStudy YearYear LithotriptorLithotriptor Stone Stone freefree)%( )%(
Retreatment Retreatment raterate)%( )%(
Cope et alCope et al 19911991 Wolf PiezolithWolf Piezolith 7575 5151
Mykulak et alMykulak et al 19921992 TherasonicTherasonic 5656 2121
CassCass 19951995 Dornier HM3Dornier HM3 6363 66
Coz et alCoz et al 20002000 Modulith SL-20Modulith SL-20 8787 2121
Lalak et alLalak et al 20022002 Dornier CompactDornier Compact 6363 NDND
Johnson et alJohnson et al 20032003 Dornier Doli SDornier Doli S 7474 66
Stone clearance is the most Stone clearance is the most important aspect for patients important aspect for patients
receiving SWL for urinary calculireceiving SWL for urinary calculi
Kouriefs et al. Ann R Col Surg Eng 2004Kouriefs et al. Ann R Col Surg Eng 2004
Improving SWL resultsImproving SWL results
Patient selectionPatient selection Prognostic variablesPrognostic variables Modification of SW deliveryModification of SW delivery
– Shock-wave rateShock-wave rate– Shock-wave pulse sequencing Shock-wave pulse sequencing – Stone targetingStone targeting– Dose escalation in SW deliveryDose escalation in SW delivery
Modification of SW treatment strategyModification of SW treatment strategy– Chemolytic pretreatmentChemolytic pretreatment– Synchronus bilateral stone SWLSynchronus bilateral stone SWL
Pressure-wave-form at the focusPressure-wave-form at the focus
Leading shock-waveLeading shock-wave (compressive force)(compressive force)– Dynamic fractureDynamic fracture– Cavitational erosionCavitational erosion
Tensile waveTensile wave
Modification of Shock WaveModification of Shock Wave delivery & Strategy delivery & Strategy
Shock-Wave Rate ModificationShock-Wave Rate Modification
Shock-wave pulse sequencing Shock-wave pulse sequencing
Stone targetingStone targeting
Dose escalation in SW deliveryDose escalation in SW delivery
Chemolytic pretreatmentChemolytic pretreatment
Shock-wave rate modificationShock-wave rate modification
FAST RATE
Shock-wave rate modificationShock-wave rate modification
SLOW RATE
Shock-wave rate modificationShock-wave rate modification
Electrohydrolic lithotriptor/Ceramic spheresElectrohydrolic lithotriptor/Ceramic spheres
– 0.4-s interval = few large fragments0.4-s interval = few large fragments
– 2.0-s interval = many small fragments2.0-s interval = many small fragments
Wiskell & Kinn. Br J Urol 1995
Shock-wave rate modificationShock-wave rate modification
Econolith 2000/118 Ceramic stonesEconolith 2000/118 Ceramic stones
– 15,20,22 KV at 30,60,120 &150 sw/min15,20,22 KV at 30,60,120 &150 sw/min
– Improved fragmentation at ↑ KV and slow rateImproved fragmentation at ↑ KV and slow rate
Greenstein & Matzkin. Urology 1999
Shock-wave rate modificationShock-wave rate modification
Dornier MFL 5000/ 12 solid stadandarised Dornier MFL 5000/ 12 solid stadandarised spherical blaster stonesspherical blaster stones
More SW needed at 20 KV to fragment stonesMore SW needed at 20 KV to fragment stones
at 117 sw/min compared to 60 or 80 sw/minat 117 sw/min compared to 60 or 80 sw/min
Weir et al. J endourol 2000
Shock-wave rate modificationShock-wave rate modification
EDAP piezoelectric lithotriptor/ Human EDAP piezoelectric lithotriptor/ Human kidney stoneskidney stones
– 3000 SW at frequencies of 1.25,2.5,5 & 10/sec.3000 SW at frequencies of 1.25,2.5,5 & 10/sec.– Better fragmentation with SLOWER frequencies Better fragmentation with SLOWER frequencies
Vallancien et al. Eur Urol 1989
Shock-wave rate modificationShock-wave rate modification
In-vivo studyIn-vivo study Artificial stones in pig kidneys/ PCNLArtificial stones in pig kidneys/ PCNL
– Stone fragmentation significantly improved at Stone fragmentation significantly improved at
SW rate of 30/min compared with 120/min.SW rate of 30/min compared with 120/min.
Paterson et al. J Urol 2002
Shock-wave rate modificationShock-wave rate modification
First clinical study (prospective radomized)First clinical study (prospective radomized) 114 patients with ureteric stones114 patients with ureteric stones Piezoelectric lithotriptor at a rate of 60 or Piezoelectric lithotriptor at a rate of 60 or
240240 Success rate was reduced for lower ureteral Success rate was reduced for lower ureteral
stones and unchanged for upper ureteral stones and unchanged for upper ureteral stones with the slower ratesstones with the slower rates
Roberts et al. J endourol 1999
Shock-wave rate modificationShock-wave rate modification
To determine the effect of To determine the effect of SWL RATESWL RATE on the treatment outcome of patients on the treatment outcome of patients
with renal and ureteric stoneswith renal and ureteric stones
Shock-wave rate modificationShock-wave rate modification Patients & MethodsPatients & Methods
A Prospective Randomized TrialA Prospective Randomized Trial Inclusion Criteria:Inclusion Criteria:
Stones Stones SingleSingle
Radio-opaqueRadio-opaque
Renal or uretericRenal or ureteric
Not more than 30mmNot more than 30mm
Exclusion CriteriaExclusion Criteria Bleeding disordersBleeding disorders Distal obstructionDistal obstruction Uncontrolled UTIUncontrolled UTI
Shock-wave rate modificationShock-wave rate modification
FOLLOW UPFOLLOW UP At 3 month visitAt 3 month visit KUB ±IVU/USKUB ±IVU/US Success: completely stone freeSuccess: completely stone free clinically insignificant gravel < 2mmclinically insignificant gravel < 2mm Statistics: Univariate AnalysisStatistics: Univariate Analysis chi-squarechi-square
Fisher’s Exact testFisher’s Exact test Mann-Whiney testMann-Whiney test
Multivariate AnalysisMultivariate Analysis
150 patients150 patientsSlow rate = 71 patientsSlow rate = 71 patientsFast rate = 79 patientsFast rate = 79 patients
SexSex 108 (72%) Male 108 (72%) Male 42 (28%) Female42 (28%) Female
AgeAge 42.1±13.4 years 42.1±13.4 yearsSlow: 41.8±14.8 yearsSlow: 41.8±14.8 yearsFast: 42.3±12.1 yearsFast: 42.3±12.1 years
((P=NSP=NS))
0
10
20
30
40
50
60
Slow rate Fast rate
Male Female
No
of p
atie
nts
(P=NS)
SEX
Results
Shock-wave rate modification
Shock-wave rate modificationShock-wave rate modification
Stone sizeStone size:: – 11.98 ± 6.0 mm11.98 ± 6.0 mm
– Range = (5-30)Range = (5-30)
Slow rate: 12.4 ± 5.9Slow rate: 12.4 ± 5.9 Fast rate: 11.6 ± 6.3Fast rate: 11.6 ± 6.3
((P=NSP=NS))
0
5
10
15
20
25
30
35
40
Slow rate Fast rate
Right Left(P=NS)
No
of p
atie
nts
Side
Results
Shock-wave rate modificationShock-wave rate modification
0
1000
2000
3000
4000
5000
6000
7000
8000
Slow rate Fast rate
Total SW
5794±3384 7438±4519(P=0.005)
Results
Shock-wave rate modificationShock-wave rate modification
0102030405060708090
100
Slow rate Fast rate
Treatment time
96.5±56,4 61.9±37.6(P=0.000)
Results
Shock-wave rate modificationShock-wave rate modification
ResultsResults Success rateSuccess rate
Entire group of patients: Entire group of patients: 141/150 141/150 ))94%94%((
Slow rate group: 70/71 (Slow rate group: 70/71 (98.5%98.5%)) Fast rate group: 71/79 (Fast rate group: 71/79 (89.8%89.8%))
((PP= 0.025)= 0.025)
Shock-wave rate modificationShock-wave rate modification
VARIABLEVARIABLE SIGNIFICANCESIGNIFICANCE
))P valueP value((
SWL rateSWL rate 0.0250.025
Stone LengthStone Length 0.0000.000
Session numberSession number 0.0010.001
Total ShocksTotal Shocks 0.0120.012
Success Rate
Shock-wave rate modificationShock-wave rate modification
CONCLUSIONSCONCLUSIONS
Shock Wave Lithotripsy Shock Wave Lithotripsy raterate has an has an independent significant impact on the independent significant impact on the successsuccess rate after rate after SWLSWL Treatment Treatment
The The EnhancedEnhanced success rate with success rate with slow slow SWLSWL rate treatment is achieved with rate treatment is achieved with Less Less
number of shock wavesnumber of shock waves
Shock-wave rate modificationShock-wave rate modification
Results are better at a Results are better at a SW rate of 60/min.SW rate of 60/min.
Especially in patients Especially in patients with larger stones with larger stones (namely those who (namely those who have worse outcome have worse outcome classically)classically)
Pace et al. J Urol 2005
Shock-wave rate modificationShock-wave rate modification
Efficacy of Slow shock wave rate is Efficacy of Slow shock wave rate is establishedestablished
Enhanced Safety and reduced renal tissue Enhanced Safety and reduced renal tissue injury → Awaits further studies.injury → Awaits further studies.
Modification of Shock WaveModification of Shock Wave delivery & Strategy delivery & Strategy
Shock-wave rateShock-wave rate
Shock-wave pulse sequencingShock-wave pulse sequencingSynchronus twin-pulse techniqueSynchronus twin-pulse techniqueSequential twin – pulse – deliverySequential twin – pulse – delivery
Stone targetingStone targeting
Dose escalation in SW deliveryDose escalation in SW delivery
Chemolytic pretreatmentChemolytic pretreatment
SW Pulse sequencing modificationSW Pulse sequencing modification
Synchronus twin-pulse techniqueSynchronus twin-pulse technique
The best angle The best angle between the 2 shock between the 2 shock tubes was 90tubes was 90oo
Enhanced stone Enhanced stone dissintegration with the dissintegration with the use of 2 energy use of 2 energy sourcessources
Sheir et al. J Endourol 2001
SW Pulse sequencing modificationSW Pulse sequencing modification
Synchronus twin-pulse techniqueSynchronus twin-pulse technique
Gross & histologic examination Gross & histologic examination of porcine kidneys showed of porcine kidneys showed renal damage when treated renal damage when treated with 2 shock tubes compared with 2 shock tubes compared to conventional under the table to conventional under the table single tube.single tube.
Sheir et al. Urology 2003
26%
34%
SF at 14/7
40%
Redo- All SF in 1/12
At 1/12
Sheir et al. BJU 2005
)Awaiting prospective randomized studies(
Clinical study
SW Pulse sequencing modificationSW Pulse sequencing modification
Sequential twin – pulse – delivery Sequential twin – pulse – delivery
HM3 pulse followed, at HM3 pulse followed, at carefuly timed close interval, carefuly timed close interval, by an auxilliary sw from by an auxilliary sw from (PEA) pizeo- electric annular (PEA) pizeo- electric annular
array. array. ↓↓ (Intensify the collapse of SW (Intensify the collapse of SW
induced bubles at stone induced bubles at stone surfac)surfac)
Zhou et al. J Urol 2004Zhou et al. J Urol 2004
SW Pulse sequencing modificationSW Pulse sequencing modification
Sequential twin – pulse – delivery Sequential twin – pulse – delivery 20 KV HM3 pulse 20 KV HM3 pulse
(500-600ms interval) (500-600ms interval) 4KV PEA pulse4KV PEA pulse
1500 SW to cylindical 1500 SW to cylindical Bego stone phantomsBego stone phantoms
Vessel phantom to Vessel phantom to mimic renal injurymimic renal injury– Consistent rupture after Consistent rupture after
30 SW at 20KV with 30 SW at 20KV with original HM3original HM3
– No Vessel rupture after No Vessel rupture after 200 SW with combined 200 SW with combined HM3/PEAHM3/PEA
Zhou et al. J Urol 2004Zhou et al. J Urol 200470
75
80
85
90
95
100Efficiency
HM3 HM3/PEA
81.3%
95.2%
Modification of Shock WaveModification of Shock Wave delivery & Strategy delivery & Strategy
Shock-wave rateShock-wave rate
Shock-wave pulse sequencingShock-wave pulse sequencing Synchronus twin-pulse techniqueSynchronus twin-pulse technique Sequential twin – pulse – deliverySequential twin – pulse – delivery
STONE TARGETINGSTONE TARGETING
Dose escalation in SW deliveryDose escalation in SW delivery
Chemolytic pretreatmentChemolytic pretreatment
Effect of stone motionEffect of stone motion
Ventilatory motion )50mm(Ventilatory motion )50mm( Focal zone of most Focal zone of most
lithotriptors )4-15mm(lithotriptors )4-15mm(
In-vitro study:In-vitro study: Motorized positionerMotorized positioner Storz Modulith SLXStorz Modulith SLX Gypsum cement stonesGypsum cement stones
Motion > 20mmMotion > 20mm
)75% of SW missed the stone()75% of SW missed the stone(
0
10
20
30
40
50
60
70
80
75% 50%
No motion 10mm motion
Fragmentation
Cleveland at al. J Endo urol 2004
Effect of stone motionEffect of stone motion
Solution:Solution: ? Stone Tracking Device? Stone Tracking Device ? Gating Device? Gating Device
– Stops the shock wave that will miss the stoneStops the shock wave that will miss the stone– Decrease injury and maintain stone Decrease injury and maintain stone
comminution efficiency comminution efficiency
Modification of Shock WaveModification of Shock Wave delivery & Strategy delivery & Strategy
Shock-wave rateShock-wave rate
Shock-wave pulse sequencingShock-wave pulse sequencing Synchronus twin-pulse techniqueSynchronus twin-pulse technique Sequential twin – pulse – deliverySequential twin – pulse – delivery
Stone targetingStone targeting
DOSE ESCALATION in SW DELIVERYDOSE ESCALATION in SW DELIVERY
Chemolytic pretreatmentChemolytic pretreatment
Dose escalation in SW deliveryDose escalation in SW delivery
In-vitro studyHM3 Lithotriptor
Begostone phantoms
500 SW at 18 KV500 SW at 20 Kv500 SW at 22 KV
CE* = 88.7%
500 SW at 22 KV500 SW at 20 Kv500 SW at 18 KV
CE * = 81.2%
1500 SW20 Kv
CE = 83.5%
* P significant
Zhou et al. J Urol 2004
CHEMOLYTIC PRE-TREATMENTCHEMOLYTIC PRE-TREATMENT
Altering the chemical environment of the Altering the chemical environment of the fluid surrounding stones, it is possible to fluid surrounding stones, it is possible to
decrease the surface energy and the decrease the surface energy and the concomitant fracture strength of renal calculi concomitant fracture strength of renal calculi
Akers SR et al. J Urol 1987
CHEMOLYTIC PRE-TREATMENTCHEMOLYTIC PRE-TREATMENT
In vitro evidence concludes that wave In vitro evidence concludes that wave speed, wave impedance, dynamic speed, wave impedance, dynamic
mechanical properties and micro hardness mechanical properties and micro hardness of EDTA treated calcium oxalate stones of EDTA treated calcium oxalate stones
and Tromethamine treated uric acid stones and Tromethamine treated uric acid stones were found to decrease compared to were found to decrease compared to
untreated (synthetic urine) control groupsuntreated (synthetic urine) control groups
Heimbach D et al. J Urol. 2004
CONCLUSIONSCONCLUSIONS
Progress in basic research of SWL allowed Progress in basic research of SWL allowed urologists to start implementing their better urologists to start implementing their better understanding of the mechanisms involved understanding of the mechanisms involved in stone comminution and tissue injury into in stone comminution and tissue injury into clinical practice. clinical practice.
Slowing the shock wave rate was shown in Slowing the shock wave rate was shown in prospective randomized clinical trials to prospective randomized clinical trials to enhance patients stone free rates enhance patients stone free rates
CONCLUSIONSCONCLUSIONS
In vivo and clinical work is needed to further In vivo and clinical work is needed to further evaluate the beneficial effects seen in, in evaluate the beneficial effects seen in, in vitro studies, with sequential twin pulse vitro studies, with sequential twin pulse
delivery and with dose escalation in SWL on delivery and with dose escalation in SWL on stone comminution while simultaneously stone comminution while simultaneously
decreasing side effects. decreasing side effects.
CONCLUSIONSCONCLUSIONS
This future work may well pave the way for This future work may well pave the way for new designs and modifications of existing new designs and modifications of existing
lithotriptors that will ultimately enhance lithotriptors that will ultimately enhance current stone free rates and minimize tissue current stone free rates and minimize tissue
injury.injury.
Thank You
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