5. PRINCIPLES OF LASER
Electrons in the atoms of the laser medium are first
pumped to excited state by external energy source.
Electrons are stimulated by external photon to emit their
stored energy in form of photons – STIMULATED EMISSION
6. Photons now strike other excited atoms to release even
more photons .
Photons move back and forth between two parallel mirrors
LIGHT AMPLIFICATION.
7. PROPERTIES OF LASER LIGHT
Monochromatic
A single pure color emitted by a single wavelength
Collimated
A beam in which all photons travel in same parallel
direction
coherent
All waves or photons travel in steps, or in phase
with one another.
10. PATTERNS OF LASER OUTPUT
Continuous : continuously pumped ,emits light continuously
Pulse: laser energy delivered with each peak over an extremely short
period of a few nanoseconds with rest period (allows time for tissues
to cool down)
Q-switched: Allows a high build-up of energy within the tube which is
then released over a very short duration of a few nanoseconds
11. Cavity dumped Lasers- produces slightly shorter
pulse of light
Mode locked lasers-produces pulses of light as
short as few pico seconds
15. When laser radiation strikes a tissue, the temperature begins to rise
100 C – 45 0C : Conformation change of proteins
500 C : Reduction of enzyme activity
60o - 99°C : Coagulation begins
100°C and above : Vaporization starts
400 -500°C : Char starts to burn
16.
17. ARGON LASER
488 - 514 nm wavelength (Blue green spectrum) in visible spectrum.
Oxyhemoglobin is target chromophore
Small spot size (0 . 1 – 1 mm) , variable in size and intensity .
Flexible delivery system
Mainly used in ophthalmological procedures.
Selective absorption of light from Laser to photocoagulate pigmented
lesion such as port wine stains, haemangiomas and telangiectasias.
Stapedotomy in otosclerosis
18. ARGON TUNABLE DYE LASER
High intensity beam that is focused on dye that
continously circulates in a second layer optically
coupled with the argon laser.
Photodynamic therapy - injection of
photosensitizer hematoporphyrin derivative.
Therapy for malignant tumors.
19. Limitations –
Also absorbed by epidermal and dermal tissues
due to melanin
Continuous mode of operation-Higher fibrosis
prevalence of postoperative pigmentary alteration
20. CO2 LASER
10,600 nm wavelength
Built –in coaxial helium neon Laser is necessary.
Highest power continuous wave laser used for cutting or ablating
tool using water as target chromophore
Focus to <500 mm and seals blood vessels less than 0.5 mm
Pulsed to accommodate thermal relaxation time (less pain and less
edema)
Used in majority of procedures except those requiring coagulation
of larger vessel
21. Comparatively a poor hemostat (not being
effective in controlling bleeding from vessels
greater than 0.5 mm in diameter)
Not transmissible through the common optical
fibre
Its use on the cords has the advantage of
producing minimal scarring therefore glottic
competency is rarely jeopardized
22. USES OF CO2 LASER
Laser stapedotomy
Recurrent respiratory papillomatosis
In paediatric patients surgery for web , subglottic
stenosis, capillary hemangiomas.
Laser cordotomy , arytenoidectomy.
Malignant & benign laryngeal tumours.
Transoral robotic surgery.
23. ND YAG: NEODYMIUM-DOPED
YTTRIUM ALUMINIUM GARNET
1064 nm wavelength with Helium-Neon (He-Ne) beam
Solid state laser with fiberoptic carrier
Deeper penetration (up to 4 mm)
Radiant energy transmitted through clear fluid used in eye and
water filled cavity urinary bladder.Ideal laser for ablation,
coagulation and hemostasis in vascular malformations
24. USES OF ND-YAG IN ENT
Ablation of obstructing tracheo bronchial lesion,
oesophageal lesions.
Removal of malignant tumors in oral cavity.
Obstruction of tracheobronchial tree –
complication hemorrhage- ND-YAG laser deep
penetration
28. 585-NM PULSED DYE LASER
Used in larynx, absorption peak 577nm
Targeted chromophore is oxyhemoglobin
Papilloma ,vascular polyps, varices and vocal fold polyps
Unlike CO2 laser ablation effects pulsed dye laser causes
involution of lesion through disruption of vascular supply .
Reduced risk of collateral thermal injury
29. DELIVERY SYSTEM
Articulated arm
Mirror lens system
Hollow wave guides
Micromanipulator
Fibreoptic fibre
Fibre tip
Robotic scanner
30. Articulated arm
use system of hollow Tubes &
mirrors to direct Laser beam to
tissue.
Micromanipulator
Focussing device connected To
microscope create an Accurate
&reproducible spot On target
tissue
31. Fibre optic cable
Inserted through biopsy channel of a fibreoptic endoscope.
End of laser fibre must protrude beyond the end of
endoscope.
Preliminary check of the length of fibre required to achieve
a satisfactory distal position.
33. Class 1 lasers pose no safety hazard (e.g., a CD
player).
Class 2 lasers emit only wavelengths in the visible
range of the spectrum and are not hazardous even
when shined directly into the eye(helium-neon laser
pointers).
Class 3a lasers are hazardous to the eye .
Class 3b and 4 laser, looking directly into the beam
close to its emergence from the applicator can
injure the eye regardless of the lens systems used.
Medical lasers are in classes 3b and4
34. Education-
1 .Appropriate credential certifying mechanism required for
physician,and nurses.
2 .Develop education policies for surgeon anaesthesiologist and
nurses
3 .Periodic review of all laser related complications
35. EYE PROTECTION AND SKIN
PROTECTION
Lasers absorbed by water (e.g., CO2) damage the anterior
portions of the eye (cornea, lens)
Wavelengths in the visible and NIR range (e.g., argon and
Nd:YAG lasers) pass through the optical media of the eye
and damage the retina.
Wavelenght specific protected eye glass with side
protectors
Double layer of saline moistened eye pad
Saline saturated surgical towel completely drape
36.
37. SMOKE EVACUATION
Seperated suction set up in aerodigestive tract
One for Smoke and steam evacuation from operative field
Constant suctioning prevent inhalation by patient Surgeon
or personnel.
38. ANAESTHESIA CONSIDERATION AND
RISK OF INTRA-OP FIRE
ET tube ignition & injury to larngotracheal mucosa
Tubes are made laser safe in two ways by using:
Noncombustible or fire-resistant materials such as a metal spiral
tube
Compressed foam (Merocel Laser-Guard), which is made laser
resistant by moistening.
Methylene blue colored saline to inflate cuff
39. 1. An endotracheal tube should be kept out of the operating field if at
all possible
2. If this cannot be done, a laser-resistant tube should be used
3. If a laser-resistant tube cannot be used, the surgeon should be able to
identify the tube the operative field at any time.
4. In this case the part of the tube closest to the surgical site can be
protected by covering it with wet neurosurgical cotton.
5. Wrapping the tube with aluminum foil can give a false sense of
security and is not advised.
40. IF LASER WILL FALL ON ET TUBE……
50ml bulb syringe and basin of saline should be available
Stop ventilation immediately
Withdraw tube and flush saline
Re establish airway immediately
Bronchoscopy to assess degree of injury
I/V steroids
Remain intubated
Repeat bronchoscopy
41. Keep lasers in standby mode when not in operation
Bystanders should remain at a safe distance.
Warning sign & locked doors
Wear protective glasses (the right kind) in the laser
environment
Never use the laser as a pointer (coworkers are not a target)
Do not aim the beam at other instruments (reflections)
Do not aim the beam at flammable materials (especially the
endotracheal tube)
Check your system (be informed)
42. LASER IN OTOLOGY
Stapes surgery
Chronic hyperplastic mucosal
suppuration
Cholesteatoma
tympanosclerosis
malleus fixation
adhesive processes
external auditory canal
exostoses
vascular lesions of the middle
ear
Tympanic membrane -middle
ear ventilation problems,
transtympanic endoscopy, and
the treatment of perforations
Inner ear- peripheral vestibular
disorders , tinnitus and
sensorineural hearing loss .
43. Three types of continuous-wave (CW) thermal
laser are currently used in otologic surgery:
The argon laser
The KTP laser
CO2 laser
The Er:YAG laser is a pulsed laser that produces
an oligothermal tissue effect.
44. LASER USE IN EXTERNAL AUDITORY
CANAL
Vascular Lesion -hemangiomas and telangiectasias of the
external auditory canal with argon laser light .
Polyps and Granulations
Exostoses: Er:YAG laser
Stenoses: co2 laser
Debulking Inoperable Tumors
45. LASER USE ON TYMPANIC MEMBRANE
laser myringotomy :
CO2 and Er:YAG lasers
opening of at least 2 mm should be created with the CO2 laser
Secretory Otitis Media
Acute Eustachian Tube Dysfunction
Barotrauma
Acute Otitis Media With Vestibulocochlear Complications
Transtympanic Endoscopy
47. Tympanic Membrane Perforations and Atrophic Scars
Graft Fixation for Tympanic Membrane Defects
epidermoid Cysts of the Tympanic Membrane
48. USE OF LASER IN MIDDLE EAR
Medialization of the Malleus
CO2 laser for dividing scar tissue and
exposing the malleus.
Resecting the distal third of the malleus
handle
Malleus Fixation
Vaporization of the malleus neck or
sclerotic foci around the malleus head
with the laser can mobilize the chain
Tympanosclerosis:
On the tympanic
membrane and on the
ossicular chain and its
surroundings causing
fixation and obliteration
of the window niches can
be removed
50. OTOSCLEROSIS
Using a drill to perforate a thick footplate obliterating the oval
window niche (as in obliterative otosclerosis) can cause harmful
vibrations to be transmitted to the inner ear.
Goal of laser stapedotomy is to create a precise opening while
protecting the inner ear and avoiding damage to the remaining
middle ear structures
CO2 laser
C/W mode.
A power of 1–22 W
pulse duration of 0.03–0.05 s
power density ranges from 4000 W/cm2 to 80,000 W/cm2.
A single laser applicationpoduces precise footplate
opening 0.5–0.7 mm in diameter .
51.
52.
53. Obliterative Otosclerosis-
The CO2 laser can vaporize a fenestra in the stapes footplate,
regardless of its thickness or degree of fixation, without
mechanical trauma to the inner ear.
Overhanging Facial Nerve
CO2 laser beam can be carefully applied tangentially at low
power (1–2 W), using short pulse lengths of 0.05 s, to remove
the bone.
A conventional stapedotomy with a curved perforator.
Redirect the CO2 laser beam with a mirror.
54. Overhanging Promontory:
Covering the footplate with saline solution or moist gelatin
sponge), the bony overhang can be ablated.
Inaccessible Footplate
Due to an abnormal course of the facial nerve or a
vascular anomaly
Fenestration of the promontory
Floating Footplate: Laser enables to create a fenestration of
the desired diameter even in a floating footplate
55. USE OF LASER IN INNER EAR
Cochleostomy
Laser cochleostomy inserting the electrode of a cochlear
implant.
Effective for an ossified cochlea
Peripheral Vestibular Disorders:
56. Tinnitus and Sensorineural Hearing LossLow-level laser therapy
Acoustic Neuroma:
Availability of fiberoptic delivery; spot size focusable to 0.15 mm,
free passage of argon laser light through media such as
cerebrospinal fluid, and good hemostatic effect of the argon laser
wavelength.
pulsed holmium:YAG laser for the removal of cranial and spinal
meningiomas and neuromas
57. LASER IN RHINOLOGY: INTRANASAL
LASER APPLICATION
Turbinate Reduction
enlarged inferior nasal turbinates secondary to allergic or
vasomotor rhinitis
Thermal damage due to laser energy causes scarring of the
mucosal epithelium.
In the submucosa, reduces the swelling capacity and secretory
functions of the turbinate.
Laser surgery of hypertrophic inferior turbinates is appropriate
only if the obstruction is largely due to severe mucosal swelling
58. Nd:YAG
Induces marked fibrosis in the mucosa with atrophy of the
mucous glands and shrinkage of the venous plexus deep
penetration .
CO2 laser : reduce turbinate mucosa by excision or
vaporization
59.
60.
61. septal surgery
include the CO2 laser, Nd:YAG laser and diode laser .
confined to removing a ridge or spur chiefly on the anterior
portions of the septum.
An S-shaped septal deformity with an ascending ridge
should still be corrected using conventional techniques.
62. Paranasal sinus surgery:
The removal of polyps in patients who refuse conventional
surgery or are poor candidates for general anesthesia.
treatment of circumscribed recurrent polyposis following
prior intranasal surgery .
70. LASER USE IN ORAL CAVITY AND
OROPHARYNX
The (CO2), (Nd:YAG), (KTP), and argon lasers are most commonly
used for soft-tissue surgery in the oral cavity and oropharynx.
occlusion of small transected vessels, providing hemostasis
bloodless field;
no-touch operating technique;
precise incisions
no need for sutures.
71. Hyperplasia of the Lingual Tonsil
Vascular Malformations
Other Benign Tumors: papillomas,fibromas, cysts, and
ranulas excision and vaporization.
Premalignant Lesions: leukoplakia and erythroplakia.
Labial and Lingual Frenoplasties
72. LASER FOR TREATMENT OF SNORING
AND SLEEP APNOEA
Laser-assisted uvulopalatoplasty (LAUP)
Appropriate for higher grades of OSA.
Contraindications for LAUP in primary snoring:
AHI greater than 20–30/h
BMI greater than 28 kg/m2
Midfacial deformities
Posterior airway space at the mandibular level smaller than
10mm
Severe concomitant medical disease
Severe neurologic or psychiatric comorbidity
75. Lasers in the Treatment of Salivary Gland Disease “optical
breakdown.”
When laser pulses of sufficiently high energy and short duration
are applied to tissue, they form a plasma that causes the sudden
volume expansion of fluids and generates a shockwave.
The laser fiber is advanced to the stone through an endoscope
The particles of the fragmented stone are either passed
spontaneously with the salivary flow or flushed out through the
working channel of the endoscope.
76. LASER FOR BENING CONDITIONS OF
LARYNX, HYPOPHARYNX AND TRACHEA
Laser Surgery of the Vocal Cords epithelial changes (vocal
nodules, leukoplakia, hyperkeratosis, acanthosis, dysplasia,
etc.),
Exudative changes in the Reinke space (vocal cord polyps,
Reinke edema).
Granulomas: (contact granuloma, intubation granuloma),
scarring, and subepithelial lesions (cysts)
77. Laser surgery can be done under general
endotracheal anesthesia and using jet ventilation
Postoperative monitoring in an intensive care unit (ICU)
following laser surgery for airway stenosis.
84. LASER SURGERY OF BENIGN TUMOURS
OF LARYNX AND TRACHEA
RECURRENT LARYNGEAL PAPILLOMATOSIS
85. SUBGLOTIC AND TRACHEAL STENOSIS
CO2 laser therapy is well accepted as the first approach to
the problem of benign stenosis of the upper airway.
Use of a rigid bronchoscope is necessary for the CO2 laser
bronchoscopy because the CO2 laser energy cannot be
transmitted through a flexible fibre.
86. COMPLICATION IN ENDOSCOPIC LASER
SURGERY IN LARYNX, HYPOPHARYNX
AND TRACHEA
Combustion of ventilation tube materials and anesthetic
gas mixtures during surgical laser use in the larynx .
Combustion of tube materials can be avoided by the use of laser-
safe tubes.
Ignition of anesthetic gas mixtures during procedures using jet
ventilation can be prevented by ventilating the patient with room
air (rather than pure oxygen) and by operating in intermittent
apnea.
On the whole, such incidents can be safely avoided by the selection
of suitable materials, operating methods, and analgesic
techniques.
87. LASER IN MALIGNANT LESIONS OF
UPPER AERODIGESTIVE TRACT
Diameter of the CO2 laser beam :
adjusted to produce either of two effects:
• Tissue ablation with a spot size of 1–4 mm or
• Tissue cutting with a spot size of 0.2–1 mm.
• The limits of the resection are defined by the tumor extent
visible under the operating microscope and can be adapted
to individual circumstances.
88. Carcinoma of the Oral Cavity
Pharyngeal Carcinoma
Laser Microsurgery of Glottic Carcinoma
T1 and T2a Glottic Carcinoma
Glottic Carcinoma with Involvement of the
Anterior Commissure
90. Carcinomas of the anterior commissure should
always be resected en bloc under high
magnification.
The vocal cord insertion on the thyroid cartilage
is completely removed along with the
surrounding perichondrium.
If subglottic tumor growth is visible below the
anterior commissure, the resection should be
extended to the inferior border of the thyroid
cartilage to ensure that extralaryngeal tumor
spread around the inferior edge of the thyroid
cartilage is not missed
91. DISADVANTAGES
1. high cost of purchase & maintenance
2. special training
3. special precautions & safety measures
4. special anaesthesia requirements
