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