High Power Laser Therapy

Original Editor - Pooja Sethi Top Contributors - Dana Alhindawi, Pooja Sethi, Lucinda hampton, Sai Kripa, Kim Jackson, Vidya Acharya and Saemeh Eldaly

Introduction

LASER means light amplification from stimulated emission of radiation. A laser is created by a specific process within the laser device to cause the controlled emission of radiation in the form of light. Laser usually comes in one colour, and it comes in a thin beam. Lasers were first invented by physicist Gordon Gould in 1958, and the first working model was built in 1960. They have been used in Europe and America for more than forty years and have been used in fields of dermatology, surgery, ophthalmology, and physical medicine and rehabilitation. Lasers are used by physiotherapists for relief of pain, to accelerate healing, and to decrease inflammation.

Difference between Low Level Laser Therapy and High Power Laser Therapy

An output power of less than 0.5 Watts is classed as Low Level Laser Therapy (LLLT) (class III in the USA), whereas lasers with an output power greater than 500 mW or 0.5 Watts are termed High Power Laser Therapy (HPLT) (class IV lasers in the USA). HPLT creates heat on the surface of the skin due to their higher power density (irradiance). LLLT is often referred to as “cold lasers” since they do not create a heating sensation during treatment.

Production of Laser

A laser device is made up of an optical cavity or chamber that contains an active medium for which the 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 mirrors is partially open. Electricity, or energy, is added to the medium, which excites it. The active medium 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 the mirror. The light production occurs in the following steps:

• The electron is pumped to a higher energy level.
• The pumping level is unstable, so the electron quickly jumps to a slightly lower energy level.
• An electron relaxes to a lower energy state and releases a photon.
• Light and an electron in an excited energy level produce two photons of the same wavelength and phase.
• Mirror reflects the photons or laser light that is emitted.

Characteristics of Laser

Due to the specific nature of laser production, it also has specific characteristics:

• Monochromaticity: ''mono'' means single. ‘Chromaticity’ meaning color. Laser, when emitted, produces a single pure colour because it has one specific wavelength.
• Coherence: Laser rays are synchronous to each other. The crest and trough of individual rays match each other.
• Collimation: It is also termed non-divergence. Laser rays travel parallel to each other.

How does Laser Work

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

Description of the video:

A high-intensity laser is a device that produces a light that carries energy and spreads it to the tissue to promote healing and improve the pain of the inflamed tissue. It penterates and spreads through subcutaneous fats, muscles, tendons, and bones. There are four different effects that lasers produce on the inflamed tissue: reflection, scattering, absorption, and transmission through a process called photobiostimulation. Its therapeutic effects include photoacoustic, biostimualtion, and thermic. High-intensity laser has a penetration of up to 10 cm, which could stimulate the free nerve endings, hence the immediate pain reliving.

Indications

Physiotherapists use HPLT basically on the presumption that energized cells from the laser increase the rate of healing.

Class IV hot laser therapy (high intensity laser therapy) can treat a variety of conditions, such as:

• Osteoarthritis of the knee, hip and ankle
• Rheumatoid arthritis
• Shoulder impingement syndromes
• Hip or shoulder bursitis
• Low back disc degeneration
• Disc herniation
• Sciatica
• Tendonitis
• Tennis elbow
• Plantar fasciitis
• Sprain
• Tenosynovitis
• Trigger finger
• Ulcers
• Incisions

Contraindications

• Pregnancy
• Tumor
• Hemorrhage
• Pacemaker
• Thrombosis
• Chronic refractory wounds

Precautions

• Should wear laser-protective glasses or goggles
• Inappropriate use of the goggles is more dangerous than their non‐use, as they may provide a false sense of security.
• Laser equipment should be placed in a controlled area with minimal access to avoid inadvertent exposure.
• Avoid laser reflection from mirrored surfaces.
• Avoid exposure of eyes, unclosed fontanels of children.

Evidence

The results of the 2018 study entitled "Effectiveness of high-intensity laser therapy in the treatment of musculoskeletal disorders. A systematic review and meta-analysis of randomised controlled trials" concluded that HILT treatment for back and neck pain significantly improved pain and disability scores compared with controls. It also commented that additional well-designed studies involving larger samples with long-term follow-up were needed to further assess each laser application, treatment region, and comparator.

A 2017 review titled "Effective treatment options for musculoskeletal pain in primary care: A systematic overview of current evidence" concluded that the evidence on effectiveness of laser therapy for shoulder pain or acute or chronic neck pain was inconclusive. With regards to knee pain, low-level laser therapy may confer added benefits to exercise and/or surgical treatment.