LASER Therapy : Type,Effects, Indiacation, Contraindication

Table of Contents

Full form LASER Therapy :

Light Amplification by Stimulated Emission of Radiation – LASER

Introduction of LASER Therapy :

Laser Therapy involves the application of low-intensity laser light to relieve pain caused due to the damage of soft tissue.
It facilitates tissue repair and restores normal cell function.
It is used by experts to heal wounds and pain.
The level of light is quite low compared to other forms of Laser Therapy, such as those used to destroy tumors and coagulate tissues.

Properties of LASER Therapy :

Compressed light of a wavelength form the cold, red part of the spectrum of electromagnetic radiation.
Monochromatic = single wavelength, single color.
Coherent = travels in straight line.
Polarized = concentrates its beam in a defined location / spot.

History of LASER Therapy :

Albert Einstein = first describe this therapy that was transformed in to laser therapy.
By the end of the 60’s Endre Master = was resorting on wound healing through laser therapy.
In early 1960’s , the first low level laser was developed .
In Feb . 2002 = the microlight 830 [ ML 830 ] received FDA approval for carpal tunnel syndrome treatment .

Class level of LASER by AEL :

It is classified by the FDA’S center for devices & radio logical health based on the Accessible Emission Limit [ AEL ] .

Incapable of producing damaging radiation levels .
Power visible LASER [ 400-700 nm wavelength,1 nW ].
Medium-power LASER [ need eye protection .
High power LASER [ more than 500 nW ] [ Present fire hazard ] .

Classification of LASER :

According to nature of the material placed between two reflecting surface
According to intensity
According to hazards

According to nature of the material placed between two reflecting surface :

Crystal lasers [ solid-state lasers ]

Ruby crystal [ aluminum oxide + chromium ]
Neodymium crystal is embedded in yttrium – aluminium garnet [ Nd: YAG ] lasers

Gas laser :

Helium neon
Argon
Carbon dioxide

Semiconductor or diode laser :

Gallium arsenide [ GaAs ]

Liquid laser :

Polypropylene
Oxazine

Chemical laser :

It is with high intensity not used therapeutically but used in industrial production .

According to intensity :

High power :

It is known as hot lasers because of the thermal response they generate .
There are used in the medical realms in numerous areas .
Including surgical cutting and coagulation , ophthalmologist , dermatological and vascular specialties .

Low power :

It is used for wound healing and pain management .
There lasers produce a maximal output of less than a milliwatt causing photo chemical , rather than thermal effects .
No tissue warming occurs .

According to hazards :

CLASS – 1	CLASS – 2	CLASS – 3	CLASS – 4
Less than 0.5 mW	Less than 1 mW	1 mW to 500 mW	More than 500 mW
Visible & non – visible	Visible	Visible & invisible	Visible
No eye or skin danger	Safe for shirt periods on eyes &extended on skin	Protective eye ware if direct viewing beam	Eye danger can result form indirect or reflected beam
Laser printer Car entry, CD player	Helium neon	Helium neon Galium Arsenide	Co2 , Argon , YAG laser
No heating / No healing	No heating / no healing	MPE can be exceeded with limited effects	Dehydrates tissue

Classification of LASER

Types of LASER :

High power LASER
Low power LASER

High power LASER :

It is also known as hot lasers because of the thermal response they generate.
They are used in surgical cutting, coagulation conditions, destroy tumors and coagulate tissues.

Low power LASER

It is also known as Cold LASER .
Low power LASER act according to the Arndt-Schulz principle which states that if a stimulus is too weak, no effect is seen.
Increased stimulation and optimal dose lead to the optimal effect, while further dose increase leads to a decreased effect and furthermore increase leads to inhibition of stimulation is also known as photobiomodulation .
Used in wound healing and pain management.
Low laser is a pain-free, non-invasive method.

High lasers	Low lasers
Surgical lasers	Medical lasers
Hard lasers	Soft lasers
Thermal lasers	Sub thermal lasers
Energy (3000-10000 Mw) lasers	Energy 1-500 mW lasers
Therapeutic (hot ) lasers produce a maximum output of 500 mW or 0.5 Watts	Therapeutic (cold) lasers produce a maximum output of 90 mW or less
1000 nm light	600- 1000 nm light

types of LASER

Production of Laser :

Laser device is made up of an optical cavity or chamber that contains active medium for which laser is named.
The chamber has mirrors on either end that are perfectly parallel to each other within a single wavelength of light.
One of the mirror is partially open. Electricity or energy is added to the medium which excites it.
The active mediums atoms are reflected back and forth across the mirrors within the chambers.this causes more excitation of atoms within the medium.
Laser light is then emitted through the partially reflective end of mirror.

Production of light :

1.Electron is pumped to a higher energy level.

2.Pumping level is unstable so the electron quickly jumps to a slightly lower energy level.

3.Electron relaxes to a lower energy state and releases a photon.

4.Light and an electron in an excited energy level produces two photons of same wavelength and phase.

5.Mirror reflects the photons or laser light is emitted.

Components of LASER generator :

Power supply = electrical power supply than can deliver up to 10000 volts & 100 amps
Lasing medium = gas , solid , liquid
Pumping device = high voltage , photo flash lamps
Optical resonant cavity = contains lasing medium

How does LASER Work?

When the light source is placed against the skin, the photons penetrates several centimetres and gets absorbed by the mitochondria.
The energy fuels many positive physiological responses resulting in restoration of normal cell morphology and function but at enhanced rate.
Targeted in hemoglobin and cytochrome oxidase, the high power diode laser could help in respiration and then in result have a good performance therapy .

EFFECTS OF LASER THERAPY :

This procedure is generally safe, effective and non-invasive to use.
Although you will feel the laser device touching your skin but the procedure is painless, no vibration or heat is felt.
The non-thermal photons of light that are emitted from the Laser, pass through the skin layers.
Once the light passes through the layers of the skin and reaches the target area.
The body tissue then absorbs the light and initiates a series of events in the cell resulting in the healing of damaged or injured tissue .
Reduction in pain and inflammation, and an overall reduction in healing time by increasing intracellular metabolism.

Most commonly used LASER :

Helium-neon (He-Ne)
Gallium arsenide (Ga-As)

Helium-neon (He-Ne) :

In this laser, a mixture of helium gas and neon is used in a pressurized tube.
This creates a laser in the red portion of the electromagnetic spectrum with a wavelength of 632.8nm.
The power out-put of the HnNe can vary .
But typically runs form 1.0 to 10.0 mW depending gas density used .

Gallium arsenide (Ga-As) :-

It uses a diode to produce an infrared invisible laser at a wavelength of 904nm.
Diode lasers are composed of semiconductor silicon that is cut and layered.
An electrical source is applied to each side and lasing action is produced at the junction of the two surfaces.
The surfaces function as partially reflecting surfaces that produce coherent light.
This laser is given in pulsed form because of the heat produced by it.

The 94 -nm laser is delivered in a pulsed mode because of the heat produced at the junction of the diode chips .

Diode laser can single beam and multi source cluster beam .

Preparation of the patient for LASER Therapy :

The skin to be treated is cleaned to lower the skin resistance.
Gels sprays or water is applied to the skin to lower the resistance .
Wearing of protective glass by therapist and patient .
Working in well-lit room .
Avoiding reflective surface with the beam .
The skin in the area of electrode placement should be cleaned by saline water , shop or Vaseline to lower skin resistance .
Electrodes should be fixed in position , using mending tapes to maintain good contact throughout treatment period.

Calculation of LASER Therapy doses :

It is dependent on :

The output power of the laser in mw
The time of exposure in second
The beam surface area of the laser in cm2

Energy or total energy [ joule ] = watt X seconds
Time of exposure [ second ] = joule / watts

Depth of penetration :

He-Ne laser energy :

Absorbed rapidly in the superficial structures, especially within the first 2-mm of tissue.
The He-Ne has an indirect effect on the tissues up to 8-10mm.

GaAs laser energy :

Ga-As laser which has a longer wavelength is directly absorbed in tissues at depths of 1-2 cm and has an indirect effect up to 5 cm.

LASER Therapy treatment techniques :

Contact technique = GaAs only for trigger points or around wound.
Non – contact technique = for superficial wound or stimulation of wound bed .

Difference between contact and non-contact technique of LASER :

NO	TITLE	CONTACT	NON – CONTACT
1	Use	Pain relief	Open wound
2	Distance between laser probe and skin	0 cm	0.5 – 1 cm
3	Held of probe	Perpendicular to skin	Perpendicular to site of radiation
4	Penetration	Deeper	Superficial
5	Power density	Maximize	Minimize
6	Reflection	Minimize	Maximize
7	Diameter of head	76 mm	13 mm
8	Power	No wasted	Wasted

Difference between contact and non – contact technique of LASER

Physiological effect of LASER Therapy :

Reducing pain
Reducing inflammation
Promoting tissue healing
Recovery form nerve injury

Consequently as a result of these effects , laser of this type could have a valuable role to play in the treatment of painful soft tissue injuries .
It is importance of accurate assessment and diagnosis to determine the area for laser application is vitally important .

Indication of LASER Therapy :

Orthopedic causes and sports causes :

General Chronic
Tennis elbow
Plantar fasciitis
Shoulder impingement
Frozen shoulder
Disc herniation
Pelvic Dysfunction
Osteoarthritis of the knee, hip, and ankle
Rheumatoid arthritis
Tendinitis
Tennis Elbow
Temporal mandibular Joint

Neurogenic causes :

Diabetic Neuropathy
Sciatica
Trigeminal neuralgia

Dermatological causes :

Hip or shoulder bursitis
Wound
Ulcer

Contraindications of LASER Therapy :

Cancer = Do not use it over the cancerous part of the body.
Epileptics = Do not use in epileptic patients.
Cardiac patients = pacemaker
Pregnancy = The laser rays should not reach the fetus.
Skin infection