Lasers in surgery

1. Surgical Lasers:
Types , Advantage and
shortcomings, List indications for
use in surgical practice
Presenter: Dr Ravi Bhushan jha
Moderator: Dr Manish K Gupta

2. LASER
 Light Amplification by Stimulated Emission of
Radiation
 The first laser was built in 1960 by Theodore H.
Maiman.
 In 1962 Dr. Goldman’s experiment was the first
use of lasers in medical history.

3. What is Laser?
 A laser is an electro-optical device that emits
organized light in a very narrow, intense beam by
a process of optical feedback and
amplification.
 Almost pure monochromatic light, i.e. single
colour or frequency (ν).

5. Laser output
2 Modes
 Continuous mode (Watts)
 Pulsed mode (Joules)
Output depends upon the Medium

6. Properties
 Collimation
 Monochromacity
 Coherence

7. Effect of Laser on tissues

8. Mechanism
Three Mechanisms involved:
Photocoagulation
Photovaporization
Photoablation

9. Photocoagulation
 A Laser heating of tissues above 50 C & below 100
C induces disordering of proteins and other bio-
molecules
 Shrink in mass – water expelled
 Heated region loses its mechanical integrity
 photocoagulation burn
 Blood vessel subjected to photocoagulation
develops a pinched point due to shrinkage of
proteins in the vessel’s wall, helps seal off the flow.

10. Photovaporisation
 With very high power densities, lasers will
quickly heat the tissues to above 100 C
 water in tissues boils and evaporates.
 Since 70% of the body tissue is water, the
boiling change the tissue into a gas.
 Results in complete removal of the tissue.
 Hemostatic incision or excision, Skin
Rejuvenation, Resurfacing

11. Photoablation
 When using high power lasers of ultraviolet
wavelength, chemical bonds are broken,
without causing local heating.
 Thermal component is relatively small and zone
of thermal interaction is limited
 Results in clean cut incision

12. Selective absorption
 A given color of light is strongly absorbed by
one type of tissue , while transmitted by another.
 Lasers pure color is responsible.
 Oxyhemoglobin in blood: Absorption of
UltraViolet, blue and green light
 Melanin a pigment in skin, hair, moles etc:
 Absorption of visible and near Infrared light

13. Selective absorption

14. TYPES OF LASER

15. Types of lasers depending upon active
medium:
Solid state laser:
a) Active medium consists of a glass or crystalline
medium (sapphire, ruby)
b) Doped with neodynium, chromium, erbium or other
ions.
c) Most commonly used; Neodynium doped: yttrium
aluminium garnet (Nd:YAG).
d) Other examples: KTP (potassium titanyl
phosphate), Alexandrite laser.

16. Types of lasers depending upon active
medium:
Semi-conductor:
a) Uses an active medium formed by doping thin layer on
surface of crystal wafer.
b) This forms a p-n junction, this comprises a diode.
c) These emit light at wavelengths between 800-900nm
d) Examples: Gallium arsenide (GaAs) laser
Liquid:
Also known as dye lasers

17. Types of lasers depending upon active
medium:
Gas
a) These apply electric current through a gas.
b) Gas lasers use noble gases and also few other gases.
i. CO2 Laser
ii. Argon Ion
iii. Excimer

18. Type of lasers according to modes of
operation:
Continuous-wave laser:
Emits a continuous beam.
Example: argon, krypton, and some CO2.
Long periods of exposure and less cooling time can
cause tissue damage
Pulsed lasers:
Emits energy in form of brief pulses rather than
continuous.
Power output of short pulsed is in mega to gigawatt
range.
That of long pulsed laser is in kilowatt range.

19. Type of lasers according to modes of
operation:
Quasi-continuous Lasers:
In this the laser is automatically switched on and off
Optically in a state of continuous wave operation
Short enough to decrease tissue heating and long
enough to maintain laser at a steady state.
Eg; KTP

20. Types of Laser
Excimer Laser
 Excited dimer
 Noble gas halide
 Photoablative Effect:
Cool Laser
 Opthalmologic surgeries:
LASIK, PRK

21. Types contd…
Argon Laser
 Tissue depth penetration only 1mm Superficial
coagulation
 Precise cutting with minimal damage to adjacent tissue
 Absorbed best in Black tissue
 Retinal photocoagulation
 Arterial Recanalisation

22. Types contd…
Dye Laser
 Pulsed Lasers
 Organic Dyes like Kiton Red, Rhodamine.
 Tunable Lasers
 Dye can be replaced-Different
wavelengths with same laser
 Port-wine stains, Pigmented lesions

23. Types contd…
CO2 Lasers
 Most effective Laser Scalpel
 0.1mm zone of Histologic Necrosis
 Cutting & Vapourising Instrument
 Seals lymphatics as it cuts through,
decreasing spread of malignant
cells
 Loss of tissues through
Evaporisation
 Skin resufacing- Laser Facelifts
 Carried via hollow tube not
fibreoptics

24. Types contd…
Nd:YAG Laser
 High penetration capacity of >5mm
 Photocaogulation
 Endoscopic Laser
 To arrest bleeding GI varices
 Debulking GIT &
Pulmonary tumours
 Coagulates Bladder tumour

25. Types contd…
Ho:YAG
 Ho:YAG lasers, like CO2 lasers, offer precise
cutting with minimal damage to adjacent tissue
 Treats tissue in a liquid-filled environment (e.g.,
saline, blood)
 Endoscopic Laser(Fibre optic delivery)
 Arthoscopy including general surgery,
urology, laparoscopy, neurosurgery,
lithotripsy, angioplasty, orthopedic surgery

26. Types contd…
Er:YAG
 Shallow penetration
 Extreme surgical precision( more precisely than co2
laser)
 Facial resurfacing, Incision and ablation of soft
tissue
 Combined Co2-Er:YAG laser now available to
decrease the amount of tissue damage

27. Types contd…
Diode Laser
 Semiconductor devices that emit Laser light as
electric current passes through them
 Tunable laser
 Fiberoptic delivery system
 Hair removal

28. Types contd…
KTP Laser
 Modified Nd:YAG laser with frequency doubling
device
 Fiberoptic delivery system
 Used in Vascular and pigmented lesion, Tattoo
removal
 Cholecystectomy

29. Applications of Laser in Surgery

30. Vascular Malformations of GIT
 Diffuse gastric antral vascular ectasia
 Colonic vascular malformation
 Argon & Nd:YAG lasers
 Photocoagulation therapy
 80% success rate in contolling recurrent blood loss &
subsequent transfusions

31. Upper GIT Carcinoma
Endoscopic laser therapy (Nd:YAG)
 Requirment:
 Lesion <4cm with no lymphnode metastasis
 Advanced carcinoma it is a palliative
 Destroy neoplastic tissues & recanalize lumen
 Relief of dysphagia 92%, perforation 10%
 Outpatient basis

32. Colorectal Cancer
 Laser therapy with Nd:YAG indicated in
 Patients with Metastatic or unresectable local
disease
 In Obstruction, Haemorrhage for Palliative
therapy

33. LIVER
 Fibrotic Liver Resection
 Nd:YAG Laser with tissue contact tip
 Insitu ablation of Intrahepatic malignancies
(metastases)
 Palliation in HCC

34. Bile duct stones
 Laser Lithotripsy
 Coumarin pulsed dye laser
 For Bileduct stones that can’t be extracted easily
 Light energy to Acoustic energy

35. Haemorrhoidectomy
CO2 or Nd:YAG Laser with contact tip
Neurosurgery
 Nd:YAG
AV malformations
Lesions at inoperable sites like Base of
skull, midbrain, floor of fourth ventricle

36. Laparoscopic Surgery
 It has been tried in many studies in Mastectomy,
lumpectomy, hernia repair, rectal fistulae,
hemmorhoidectomy.
 Even tried in the laparoscopic surgeries like
cholecystectomy(KTP/Nd:YAG), adhesiolysis,
metastases

37. Vascular Applications
 Smart Laser-
 Combination of Helium laser for fluorescence
excitation & Holmium laser for plaque ablation are
tried
 Laser Angioplasty – Co2,Argon,Nd:YAG
 Laser assisted balloon angioplasty done in
localised lesions of common iliac & superficial femoral
artery

38. Urology
 Renal stones - Laser lithotripsy
 Coumarin-based pulsed dye laser
 Light energy is delivered through Flexible quartz
fibers, directed Endoscopically onto a calculus
 Mechanism of action occurs via plasma

39. BPH
 Photovaporisation - Tissue water is
vaporized resulting in an instantaneous debulking
of prostatic tissue.
 KTP or Greenlight is commonly used for its
vaporization effects on prostate tissue.
 Less bleeding and fluid absorption than standard
TURP
 Lack of tissue for HPE

40. Skin lesions
Ruby lasers first used for tattoo removal
Argon lasers are readily absorbed by Hemoglobin are
used in treatment of Port-wine stains.
CO2 Lasers -used for superficial lesions (Condyloma
acuminata, Haemangioma of external genitalia, early
penile carcinoma. ) and resurfacing of the skin.
Dye lasers are useful for removal of tattoos as well as
other pigmented (Port wine stain) and vascular
lesions. (Rx of choice)

42. Selective absorption : Absorbing component being Melanin pigment in
hair and follicle, it is best worked with a Red light ruby laser.

43. Advantage
 Bloodless field
 Excellent Haemostasis
 Excellent Healing
 Allow precise Microsurgery
 Less postoperative pain & oedema
 Lower infection rate
 Outpatient procedure

44. Disadvantages
 Atmospheric contamination: Laser Plume
 Mutagenic,Teratogenic or vector for viral infection.
 Misdirection of laser energy
 Perforation of viscous or large blood vessels
 Eye damage
 Skin damage
 Fire and explosion
 Gas embolism

45. Safety with lasers
 Hazards electrical, mechanical, chemical, biological, optical
and firehazards as well as toxic effects of laser plume.
 Laser light, either transmitted directly, or reflected into the
eye, may be very dangerous.
 Visible spectrum- the retina may be burned (permanent blind
spot) or the head of the optic nerve may be damaged (partial
or total blindness).
 Infrared light -cornea, lens, and aqueous and vitreous
humour
• Eye and skin are the most susceptible
• Effects vary depending upon the wavelength and exposure
duration

46. Take Home Message
 3 properties: Collimation , Monochromacity, Coherence
 3 mechanism: Photocoagulation (50-100C) ,
Photovapourisation(>100c) , Photoablation( Breaks
chemical bond)
 Selective absorption- given colour strongly absorbed by
one type of tissue
 Types depending upon medium-Solid, Semiconductor,
Liquid , Gas
 Types depending upon mode of output- Continuous(
Ar,Cr), Pulsed ( Dye), QuasiPulsed ( KTP)

47. Take Home Message
 Excimer Laser- Cool laser- LASIK
 Argon Laser- Coagulation of blood vessels, Black tissue
 Dye Laser- Pigmented skin lesions
 Co2 Lasers- Laser SCALPELS,
 Nd-YAG Laser: Endoscopic laser,
 Ho-YAG Laser- Endoscopic laser in liquid medium
 KTP Laser: Vascular and pigmented lesion