laser in surgery
TRANSCRIPT
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SEMINAR PRESENTATION
DEPARTMENT OF SURGERY
ABUTH ZARIA
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USERS OF LASER IN SURGERY.
PRESENTERDR.IBRAHIM A.
MODERATORPROF.MBIBU.H
DATED 25TH;SEPT.2011.
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INTRODUCTION
Light
Amplification
by theStimulated
Emission
ofRadiation
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Introduction
A device that produces highly directional
light beam
Can be focused and positioned accurately
on a biological material
Has sufficient energy to affect the material
in a number of ways
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INTRODUCTION CONTD
Most medical applications rely on heat produced by laserlight
Laser light when absorbed is used in vapourizing,coagulating, or cutting tissues
Delivery of laser via optical fibres is useful in endoscopicprocedures
Non-thermal application is photodynamic therapy(PDT)
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Introduction contd
Einstein first conceptualized laser in 1917
First laser built 1960 Theodore H. Maiman(1960)
ruby crystals
Lasers were not used in operating room untilabout 1970
Can cause serious injury to patients, anaesthetistsand other theatre workers
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BASIC PHYSICS
Atom-consists of nucleus ( protons and neutrons)
and electrons
Quantum theory-electrons confined to certain energy levels
-can only move between these levels-by gaining or losing well defined amountof energy
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Resting atom: spontaneous emission of
radiation
Photon of
specific energy
strikes a resting
atom. Atom absorbs it
& gets excited
Excited atom
comes back to
resting state and
emits light
Energy
Absorbed energy
emitted
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Basic physics contd
Energy of radiation
E = hv
E =energy of the photons
h = planks constantV = photon frequency
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Basic Physics contd
Total intensity =k(nA)2
A = amplitude
n = total number of atoms
k = constant
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STIMULATION
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AMPLIFICATION
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Stimulated emission
Singular property of laser beam
Process that effectively dumps storedenergy from an active material into a light
beam passing through
Accurately alligned mirrors
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Basic composition of lasers Power source
Tube cavity with lasermedium
Mirrors total and partialreflecting
Laser media:
ruby crystals &Neodymium in yttriumaluminum garnet (ND-YAG)
Gases or mixture:
helium, argon, Co2 ,Excimer (exciteddimer)
Dye lasers: organic dyein liq soln.e.g.Rhodamine
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Generation of the beam
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Slide 25
K1 KHADIJAH, 9/29/2011
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Peculiarities contd
Laser Beams with wavelengths in a visible &
near the infrared portion of spectrum aretransmitted efficiently along flexible quartz
fibreoptic cables.
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Semiconductor
-Gallium arsenide laser
Liquid
. Dye lasers
Gas
. Argon
. C02
. Krypton
. Helium
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RUBY LASER
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Semiconductor laser
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Laser on tissue
Diff have diff absorption xteristics in tissue
Uv strongly absorbed, effect on surface only
As increase from blue>Green>Red, tissue become
more transparent and allow light to penetrate
Nd-YAG (near infrared = 1064) penetrate>argon (Blue= 488, green= 514)
As increases into the infra red region, tissue becomemore opaque and transmission reduces in the co2range ( = 10600nm) and hence effect limited on thesurface
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laser effects
No thermal effect at low intensity but can activatephotosensitive compd. leading to toxic reactions(photodynamic Therapy)
Photo thermal effect at high intensity for hemostasis,tumor vaporization, laser knife
Photomechanical effect lead to shock wave
Photo ablation effect (at extreme short interactiontime and peak pulse power
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USES OF LASERS
Broadly, lasers are used for
Photocoagulation of blood vessels.
Photo vaporization of unwanted tissues.
Photo fusion of adjacent structures.
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Surgical specialties uses
OPHTHALMOLOGY.
The 1st surgical specialty to use lasers
Treatment of diabetic retinopathy
Spot welding of retinal tears to prevent
detachment
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Ophthalmology contd
Iridectomy in closed angle glaucoma
Trabeculoplasty in open angle glaucoma
Ablation of posterior lens capsule(Intracapsular cataract extraction).
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Neurosurgery contd
Photocoagulation of brain aneurysms
(Argon lasers)
Neurosurgical pain relief (laser myelotomy or
anterolateral cordotomy).
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Thoracic surgery
Nd-YAG for obstructive bronchial ca viaendoscope
Coagulation of bleeders in haemoptysis
Intraluminal in operable/ non resectable tumors
Argon&Nd-YAG in laser assisted ballonangioplasty for impassable arterial obstruction.
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Thoracic surgery contd.
Cardiovascular surgery
- IHD (Ischaemic Heart Disease)
treatment using laser drills into
myocardium.
- Laser angioplasty of coronary &
peripheral arterial artheromas &thrombosis.
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Surgical specialities contd.
Gastroenterology:
- Control of upper GI Haemorrhage
(PUD, Varices, Ca).
- Hepatic resection eg PLCC or
secondaries.
- Haemorrhoids.
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Gastroenterology contd
Upper GIH (Nd-YAG) to ring the bleeders
Angiodysplasia, hereditary haemorrhagic
telangiectasia of stomach duodenum and colon
Oesophagitis, Mallory Weiss, gastritis
Palliation of malignant dysphagia
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Pancreatico-hepatibiliary system
Biliary calculi lithotripsy (Nd-YAG)
Recanalization of malignant stricture of bil. tree.
To allow endoscopic stenting
Hepatic resection (Nd-YAG) to reduce bld. loss(thermal knife)
Hemoistasis in liver trauma
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Urology contd.
Urology
- Bladder tumor resection
- TULIP (Transurethral Laser Induced
Prostatectomy)
- Internal laser urethrotomies in
strictures.
- Fragmentation of renal stones (Nd
YAG).
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Gynaecology contd.
Colposcopic treatment of CIN (CO2)
VIN and VaIN.(CO2)
Laser ablation of endometrium (Nd-YAG) in
menorrhagia (obviates hysterectomy)
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Benefits of lasers
High precision surgery, allows controlledpreservation of normal tissues.
Bloodless surgical field
Minimal wound contraction (No tissue reaction)
Provides No Touch surgery with better Asepsis.
Minimal pain and early convalescence
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Hazards
To Patient:
Excessive burning (injury to tissues other than
site being treated).
Visceral perforation
Excessive bleeding (ineffective in presence ofgross bleeding
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HAZARDS CONTD.
To Surgical Staff
Smoke inhalation and vaporization of viral and
bacterial particles Accidental skin exposure
Corneal or retinal burns
Fire hazards in presence of inflammableanaesthetic agents or high oxygen atmosphere.
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LASER SAFETY
The American National standard safe use of
laser in health facilities which was revised in
2002.
LASER Officer and LASER Committee
Staff training
Avoidance of litigation
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Laser safety contd
Use non-volatile anaesthetic agents
Using wet swabs to surround operation field
Suction to remove laser smoke/vapour.
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