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Dr Disha sharmaENT-HNSIGMC Shimla
light amplification by stimulated emission of radiation
Albert einstein theodore Maiman
C.Kumar N.Patel
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
Photons now strike other excited atoms to release even more photons .
Photons move back and forth between two parallel mirrors LIGHT AMPLIFICATION.
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.
Solid : Nd: YAG laser Liquid : Organic dye laser.( rhodamin 6G ,
disodium fluorescein) Gas : Helium Neon (HeNe) laser, CO2,Argon
and Krypton Gas laser. Semiconductors : Gallium-Arsenide -Diode
laser Excited dimer (Eximer Laser) : Argon
fluoride and Krypton fluoride
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
Cavity dumped Lasers- produces slightly shorter pulse of light
Mode locked lasers-produces pulses of light as short as few pico seconds.
Power Spot size Exposure time
Absorption Scattering Reflection transmision
Photothermal Photomechanical Photochemical Photoablative
• When laser radiation strikes a tissue, the temperature begins to rise
• 10 0 C – 45 0 C : Conformation change of proteins
• 50 0 C : Reduction of enzyme activity • 60 0 - 99°C : Coagulation begins • 100°C and above : Vaporization starts • 400 0 -500°C : Char starts to burn
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
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.
Limitations –Also absorbed by epidermal and dermal
tissues due to melanin
Continuous mode of operation Higher fibrosis
prevalence of postoperative pigmentary alteration
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
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 glotticcompetency is rarely jeopardized
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.
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
Ablation palliation of obstructing tracheobronchial lesion, oesophageal lesions.
Removal of malignant tumors in oral cavity.
Obstruction of tracheobronchial tree –complication hemorrhage- ND-YAG laser deep penetration
Limitations Greater scatter than CO2 Deep thermal injury Risk for transmural injury
532 nm wavelength with Oxyhemoglobin as primary chromophore
• Continuous wave (CW) mode to cut tissue
• Pulsed mode for vascular lesions.
• Q-Switched mode for red/orange tattoo pigment • Delivery • Insulated fiber, fiber handpiece, scanner, or
microscope for CW/pulsed mode • Articulating arm for Q-Switched mode
Tosillectomy Pigment dermal lesion Revision stapedotomy Limitation – unintended thermal injury
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
Articulated arm Mirror lens system Hollow wave guides Micromanipulator Fibreoptic fibre Fibre tip Robotic scanner
Articulated arm use system of hollowTubes & mirrors to direct Laser beam to tissue.
MicromanipulatorFocussing device connectedTo microscope create an Accurate &reproducible spotOn target tissue
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.
Hollow wave guide
fibre tip
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
Education- 1 appropriate credential certifying mechanism required for physician, nurses to become involved with each.
2 Develop education policies for surgeon anaesthesiologist and nurses
3 periodic review of all laser related complications
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
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.
ET tube ignition & injury to larngotrachealmucosa. Tubes are made laser safe in two ways by using: noncombustible or fire-resistant materials
such as a metal spiral tubecompressed foam (Merocel Laser-Guard),
which is made laser resistant by moistening.Methylene blue colored saline to inflate cuff
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 in 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.
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
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)
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 .
Three types of continuous-wave (CW) thermal laser are currently used in otologicsurgery:
the argon laser the KTP laser CO2 laser The Er:YAG laser is a pulsed laser that
produces an oligothermal tissue effect.
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
laser myringotomy : CO2 and Er:YAG lasers opening of at least 2 mm should be created
with the CO2 laserSecretory Otitis MediaAcute Eustachian Tube DysfunctionBarotraumaAcute Otitis Media With Vestibulocochlear
ComplicationsTranstympanic Endoscopy
Tympanic Membrane Perforations and Atrophic Scars
Graft Fixation for Tympanic Membrane Defects epidermoid Cysts of the Tympanic Membrane
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
Chronic Otitis Media Cholesteatoma Vascular Lesions (glomus tumour)
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 CW 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 .
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.
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 fenestra of the desired diameter even in a floating footplate
Adhesions are frequently present and are vaporized with the CO2 laser using the safe and effective laser parameters
prosthesis is exposed by noncontact vaporization of the fibrous attachments
the soft tissue covering the oval window niche is uniformly vaporized
Once the distal end of the prosthesis has been cleared of all fibrous attachments, it is detached from the incus and extracted with a 90° hook 2 mm long
. tissue at the center of the oval window is then uniformly vaporized incus is badly eroded, a malleovestibulopexydone
Cochleostomy Laser cochleostomy inserting the electrode
of a cochlear implant. effective for an ossified cochlea Peripheral Vestibular Disorders:
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
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
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
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.
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 .
Lacrimal Duct Surgery:
Laser-Assisted TranscanalicularDacryocystorhinostomy
Laser-Assisted IntranasalDacryocystorhinostomy
Laser-Assisted Dacryoplasty
Choanal atresia:
epistaxis
Hereditary Hemorrhagic Telangiectasia
Benign tumours Malignant tumours synechia
Laser Treatment of Rhinophyma
intranasal Photodynamic Therapy
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.
Hyperplasia of the Lingual TonsilVascular Malformations Other Benign Tumors: papillomas,
fibromas, cysts, and ranulas excision and vaporization.
Premalignant Lesions: leukoplakia and erythroplakia.
Labial and Lingual Frenoplasties
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 10 mm Severe concomitant medical disease Severe neurologic or psychiatric comorbidity
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.
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)
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.
Contact granuloma
Vocal cord polyp
SubepithelialVocal cordcyst
Zenker diverticulum deficient or delayedrelaxationof thecrico-pharyngeusmuscle
Supraglottic StenosisGlottic Airway Stenosis Bilateral Recurrent Nerve ParalysisArytenoidectomy Cordectomy Posterior cordectomy Temporary lateral fixation
Subglottic and Tracheal StenosesAirway Stenosis Due to Malignant Disease
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.
combustion of ventilation tube materials and anestheticgas 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.
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 tumorextent visible under the operating microscope and can be adapted to individual circumstances.
With cancers involving the anterior commissure, the perichondrium about the vocal cord attachment should be dissected from the cartilage with a round knife to
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
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 tumorspread around the inferior edge of the thyroid cartilage is not missed
The resection can be extendedto the perichondrium of thethyroid cartilage and cricoidcartilage, to the thyroid andcricoid cartilages themselvesto the arytenoid cartilagethe cricothyroid ligamentand the extralaryngeal soft tissues
SUPRAGLOTTIC T1 AND T2carcinomas of thesuprahyoid epiglottis orventricular fold can usually
be clearly exposed and excisedInfrahyoidepiglottisincision in the glossoepiglotticvallecula and splitting theepiglottis in the midline,including the preepiglottic fat preserving the vocal cords andarytenoid cartilages
poorest prognosis . High rate of local tumor recurrence High cervical lymph node metastases at the
time of diagnosis metachronous distant metastases high incidence of metachronous second primary
tumors. Laser surgery appears to be effective for T1
T2 hypopharyngeal cancer treatment as long as clear surgical margins can be achieved.
1. high cost of purchase & maintenance2. special training3. special precautions & safety measures4. special anaesthesia requirements