Charles D Kelman MD 1930-2004 Principles of n … · 2018. 6. 5. · Capsule Tension Ring n Size of...
Transcript of Charles D Kelman MD 1930-2004 Principles of n … · 2018. 6. 5. · Capsule Tension Ring n Size of...
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Principles of Phacoemulsification
David A. Wilkie, DVM, MS, DiplomateACVO
ProfessorDepartment Chair
The Ohio State [email protected]
Charles D Kelman MD 1930-2004
n �Father of Phacoemulsification�n 1962 - invented cryoproben 1966 - first animal phacon 1967 - first human phaco
- 76 minute phaco time- Inspired by dental unit
Phacoemulsificationn Technology and techniques are rapidly
evolving
This is a technology driven procedure
This is a technology driven procedure
You get what you pay for
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Phacoemulsificationn Handle
n Ultrasonic energy n Fluidics
n Irrigation n Bottle height
n Aspirationn Flow raten Vacuum
n Foot Pedaln Controls device
Phacoemulsification
n Ultrasonic phacon Electrical energy converted into
mechanical energyn Tip vibrationn Generates friction which creates
heat - thermal damage
Phacoemulsification
Phacoemulsificationn Older generation machines
n More energy n Increased thermal damage
Phacoemulsificationn Reuseable tips & tubing
n Cost effective?n How do you clean and sterilize???
n Disposablesn $/patient
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Should you re-use your materials?
Sterilization n Do Not gas your tubing or handpiecesn Gas does not sterilize areas that are
wet or have trapped liquidn Clean after each use
n Distilled watern Steam autoclave
n Routinen Flash
Phacoemulsificationn Power controlled by
frequency and stroke length
n Frequencyn 35,000 - 45,000
cycles/sec (Hz)n Lower frequency = less
efficientn Higher frequency =
excess heat
Phacoemulsificationn Stroke length
n 2-6 mil (thousands of an inch)
n Most operate at 2-4 miln (0.1-0.12mm)
n Longer the stroke lengthn Increased heatn Increased cavitationn Increased physical impact on
lens
Phacoemulsificationn Emulsification of lens
n Jackhammern Physically striking the lens
n Cavitationn “The formation and immediate implosion of
bubbles in a liquid”n High and low pressuresn Microbubblesn Implosion of microbubblesn Temperature at implosion of 13000o Fn Shockwave at implosion 75,000 PSI
Phacoemulsification
Cavitation
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Phacoemulsificationn Transducer
n 40,000 cycles per secondn Power related to stroke lengthn Destructive events
n Cavitationn Fluid and lens particles at tip reach velocities of 72 km/hrn Shock of the acoustical waven Mechanical impact of tip against lens
Phacoemulsificationn 15,30,45 degree cutting tips
n 45 degree - improved cutting efficiency, more difficult to occlude
n Flare tipsn Angled tips - Kelman
Phacoemulsificationn Various needle designs
KelmanFlare
Holding Strength
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Angle of the tip can be varied to facilitate occlusion
Phacoemulsificationn Minimal phaco energy is desired
n Stroke lengthn Presetn Foot pedal
n Durationn Efficient surgeonn Pulse or burst mode
n Emmisionn Tip selection
n Kelmann Flaredn 0, 15, 30, 45 degree
Preset
100%
50%
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Phacoemulsificationn Kelman tip
n Hard nuclein Flare tip
n Direct cavitation into tip
Phacoemulsificationn Fluidics
n Inflown Bottle height
n Outflown Incisionn Aspiration raten Vacuum preset and
demanded
Phacoemulsification
n Fluidicsn Irrigation
n Cooling at incisionn Maintain the anterior chamber
n Aspirationn Aspiration flow in ml/minuten Vacuum in mmHg
PhacoemulsificationInfusion bottle height-every 15cm above the eye = 11mmHg
Active fluidics
Phacoemulsification
n Fluidicsn Peristaltic
n Wheel with rotating bearings
n Venturin Compressed gas
n Diaphragmn Piston and valve
n Hybrid
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Phacoemulsification
n Irrigation/Aspirationn Peristaltic
n Wheel with rotating bearings
n Diaphragmn Piston and valve
n Venturin Compressed gas
Diaphragm
Phacoemulsificationn Peristaltic pumps �safer� as they take
several seconds to build to preset vacuumn More forgiving
n Diaphragm and Venturi pumps give preset vacuum immediatelyn More responsiven Better for posterior segment work
Irrigation Irrigation/Aspiration
Know where the aspiration reversal switch is
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Phacoemulsificationn Aspiration reversal
Phacoemulsificationn How to �Set the Dials�?n Goal is a �stable� eye. Not too soft, not
too hardn Just Right
Vacuum Settingsn Standard Phaco
n 20 mmHg minn 70 mmHg max
n Phaco Pulsen 28 mmHg minn 220-300 mmHg max
n I/An 26 mmHg minn 300 mmHg max
Vacuumn Do not need high vacuum when
sculpting as lens is stablen Higher vacuum for cracking, chopping
and fragments to �hold� will allow lower phaco energy
Phaco
Vacuum
Tip occlusion
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Phacoemulsificationn Surge
n Tip occlusion followed by fragmentation and immediate aspiration
n Shallowing of the chambern Newer technology addresses this
n Microprocessors sample vacuum/flow 50 times/sec
Higher the vacuum the greater the surge effect
Group L- 50 mm bottle height- Vacuum 80 mmHg- US time 117 +/-12s- Volume 165 +/- 54ml
Group H- 120 mm bottle height- Vacuum 150 mmHg- US time 96 +/-31s- Volume 255 +/- 33ml
Fluid in vitreous and anterior hyaloiddetachment
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n Fluid in the vitreousn Worse opposite entry siten > with longer irrigation timen > with increased fluidics
n Bottle heightn Vacuum
n Would stage of cataract and state of vitreous affect this?n Could be associated with:
n Retinal detachmentn Vitreous contamination and endophthalmitis
Phacoemulsificationn Pulse setting
Phacoemulsificationn Pulse/Burst Mode
n Decrease overall power deliveryn Provides deeper more stable A/Cn I choose to increase vacuum
setting to 300-350 mmHg max setting
n Think of increased vacuum as an extra hand in the eye to hold and pull the sculpted lens apart
Phacoemulsificationn Pulse/Burst Mode
n Pulse - Alcon Legacyn 50-150 msec of power followed by variable
period of aspiration only
n Burst - Allergan Sovereignn 80-120 msec of power followed by fixed short
period of aspiration
Phacoemulsificationn Whitestar®, Hyperpulse® technology
n �Cold Phaco�n Instead of 2-6 pulse/sec get 50
microbursts/secn No time to create thermal effectn Minimal cavitation
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Pulse PhacoK9 unstable lens
Coaxial standard phacovs.
High vacuum pulse phaco (350 mmHg)
Watch the lens movement decrease when switched to high vacuum pulse
Hydrodissectionn Inject BSS between capsule and cortexn Separates posterior cortex/nucleus from the
posterior capsule
Hydrodissectionn Better for 2-handed technique
n Divide & conquern Chip & flipn Phaco chopn CTR placement in unstable lens
n Lens free to rotate in the capsule bagn Less desireable for one-handed
coaxial phaco
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Hydrodissection + CTR Hydrodissection
Hydrodelineationn Injection of BSS into nucleus n Separates nucleus from the epinucleus
n Used for hard nucleus so epinucleus protects capsule
Phacoemulsificationn Trauma
n Time n Surgery time - 10-17 minutes/eyen Phaco time - 0-120 seconds/eye
n Fluid Volumen 50-200 ml/eye
n Turbulencen Phaco Energyn Chamber bounce
Intraocular Surgeryn �The enemy of GOOD is BETTER�
Phacoemulsificationn Surgeon must be adaptable
n Know more than 1 techniquen No one single method works on all
cataracts
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Phacoemulsificationn Divide and conquern Chip and Flipn Croissantn Phaco Chopn Stop and Chopn Other
Phacoemulsificationn One handed vs two handed technique
Zonules are like corn silk. They entwine and extend far posterior
Pull on the lens….You pull on the zonules
Pull on the zonules….You pull on the ora
Pull on the ora….You pull on the retina
And it may lead to…
Retinal tears, detachment
Phacoemulsificationn One-handed technique
n Sculpt a large, deep bowln Rotate lens and divide & conquer
n Crack the bowln Increase suction, use pulse
n Flip bowl over to phaco posterior aspectn Pressure at near side, push down and awayn Use suction to pull bowl over as it flips
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One-handed technique Coaxial forces
One-handed phaco
One-handed techniquePulse setting, Vacuum 300 mmHg One-handed technique
One-handed technique One-handed technique
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6 Year – old Diabetic DogPhaco -37 sec, 120ml Phacoemulsification
n Two-handedn Hard nuclein Unstable lensn Shorten surgical
time and decrease phaco power
n Zonular dehisence <120 degreesn 2-handed phacoemulsificationn Hydro-dissection + CTR and IOL in
the bag IOL or Sutured IOLn Zonular dehiscence >120 degrees
n 2-handed phacoemulsification or ICLEn Sutured IOL
THIS IS OFTEN AN INTRAOP DECISION
Lens Subluxation/Luxation n 2-handed phacon Hydro-dissection + CTR
and IOL in the bag IOL or Sutured IOL
n Zonular dehiscence >120 degreesn 2-handed phaco or ICLEn Sutured IOL
nZonular dehiscence <120 degrees
Phacoemulsificationn Two-handed
n Side-port incision 45o- 90o
from coaxial phacon 1mm keratomen When to perform?
n I choose to enter after phaconeedle in the eyen Can choose to switch mid-surgery
n Insert rotator, manipulator, choppern Retract into A/C when not in use
Two-handed conversion
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Choppers, manipulators
Warren C: Veterinary Ophthalmology 7:348-351, 2004Maggio F, et al: ACVO 2008
Phaco Chop
Divide & Conquer
Two-hand phaco for unstable lens
XX
Divide & Conquer
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Incorrect Divide & Conquer Incorrect Divide & Conquer
FDA Approved
n Stabilize the lens capsule when zonular weakness, degeneration, dehiscence is present
n Prevent capsular phimosisn When to implant?
n Pre or Post phacon Size selection
Capsule Tension Ring
n Size of CTR matches size of IOLn 12mm IOL = 12.5 mm CTRn 13mm IOL = 13.5 mm CTRn 14mm IOL = 14.5 mm CTR
Capsule Tension Ring
n Risks of CTR implantation?n 47 dogs, 94 eyesn One receives CTR, other is controln 1 yr follow upn No signif diff CTR vs no-CTR
Capsule Tension Ring
Hoy S, Wilkie DA, et al: CTR safety and complication rates in stable & unstable lenses. Veterinary Ophthalmology 11:426, 2008
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CTR Pre-phacoZonular dehiscence >120 degrees
240 degree instability-2 handed
300 degree Anterior luxationTwo Handed with vitrectomy and ECP
Pre-op IOP 32 mmHg
Complete Lens Luxation- anterior/posterior
Personally – I always try to remove by phaco. I NEVER use a cryo-technique
Medical vs Surgicaln Posterior entrapment plus a miotic
n No significant mean time to glaucoma or vision loss
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Phaco vs ICLEn Better vision preservation with surgery
vs. medical for subluxation vs luxationn Better success for Phaco vs ICLEn Retinal detachment
n 28% with ICLEn 6% with Phaco
n Glaucoman 60% have IOP concerns longterm -ECP
Manning S, Renwick P, Heinrich C, Cripps P: Lens instability in the dog: A retrospective study of surgical results in 102 cases (155 eyes). Vet Ophth 12:63, 2009
K9 Anterior lens luxation 2-hand phaco, vitrectomy, ECP
O�Malley Lens
Courtesy of Dr. Brian Gilger
K9 Posterior lens luxation 2-hand phaco
Want a high viscosity visco like 2% Acri-Syn
n Sabet® Lenticular Safety Net
Sabet® lenticular safety net
Cortical Aspiration
n ≥0.5 mm port required for canine cortex
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Cortical Aspiration Cortical I/A0.5mm curved
Bi-Manual Cortical I/ABi-Manual Cortical I/A
Capsule Vacuum
Value of this step??
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Capsule vacuum Capsule polish
Whitman Shepherd Capsule Polisher
n Removal of Viscoelastic
AcriVet 60V IOL Forceps fold acrylic IOL
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Modified ab-externo IOL
Wilkie DA, et al: A modified ab-externo approach for suture fixation of an intraocular IOL in the dog. Veterinary Ophthalmology 11:43-48, 2008
Modified ab-externo IOL
Wilkie DA, et al: A modified ab-externo approach for suture fixation of an intraocular IOL in the dog. Veterinary Ophthalmology 11:43-48, 2008
Ventral suture placement
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Dorsal suture placement -PMMA IOL
Dorsal suture placement -Duet® Forceps
IOL Placement Suture Fixation
Modified ab-externoCow Hitch Technique
Acrivet Acrylic IOL for Modified ab-externocow-hitch technique
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Acrivet Acrylic IOL for Modified ab-externocow-hitch technique
Ozil® torsional phaco
Active fluidics
Phacoemulsificationn Change is difficult, but not always badn We are now the �conventional
surgeons� and newer technologies are challenging us Dr Wilkie Dr Allgoewer
My new residents!!
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