THERAPEUTIC LASERS IN MEDICINE A SHORT REVIEW

Michael Mikowski, DO, DMD February 24, 2018

2018 Annual FOMA Convention

I have NO financial agreements with any companies or individuals I am getting NO financial gain for this presentation

Light Amplication Stimulated Emmision Radiation LASER Purpose-Therapy lasers but basics of lasers necessary understand why

First concept of LASER-Einstein 1917 proposed the concept of stimulated emmision while working on the interplay of matter and radiation-the beginnings of Quantum Theory Einstein- one of the founders First working LASER—1960 Hughes research ruby laser-red light -694nm

First medical use of Lasers-1962 Goldman removal of tattoos In 1967-Hungarian physician by accident found laser increased hair growth and wound healing on rats---discovered by accident as he was trying to see if laser radiation could cause cancer Important – the initial concept of “cutting” vs “therapy “ laser

How a laser works—basic

Components of a typical laser 1-gain medium 2-Laser pumping energy 3-High reflector 4-Partial reflector 5-Laser beam

Diode laser work essentially the same except for oscillation vs amplication LASER vs LOSER!

Lasers

• Cutting/surgical • Therapy—pain management-rehab-regeneration-functional restoration-wound healing -etc

Physiology of laser interaction with tissue Already have a natural model Photosynthesis Chlorophyll in chloroplasts(mitochondria) Light –dependent reaction---light(photon) hits a molecule of chlorophyll—releases an electron—travels down electron transport chain—ATP best wavelengths—450nm and 655/705nm

In normal cellular respiration-chemical energy is used to cause the release of electrons that travel down the electron transport chain Instead of chemical energy—lasers can can cause the release of electrons to electron transport chain and production of ATP

Chromophores are components of various

cells and sub-cellular organelles which absorb light. Similar to chlorophyll

Cytochrome C oxidase in mitochondria

Increased ATP Production

Cellular mechanisms of Schematic diagram showing the absorption of red or near infrared (NIR) light by specific cellular chromophores or photoacceptors localized in the mitochondrial. During this process in mitochondria respiration chain ATP production will increase, and reactive oxygen species (ROS) are generated; nitric oxide is released or generated. These cytosolic responses may in turn induce transcriptional changes via activation of transcription factors

Two possible sources of nitric oxide (NO) release from cytochrome c oxidase (CCO). Path1 shows CCO can act as a nitrite reductase enzyme: Path 2 shows possible photo-dissociation of NO from CCO.

Note-biologic optimal light window 600 nm to 1100nm most used 808nm-815nm 940nm-980nm Also most studied

The most important wavelength is in the range of 800 to 850nm with the peak around 810nm. This is the best wavelength to get a combination of deeper penetration and cellular interaction. Laser in this range are the optimized to interact with the mitochondria and they trigger an increase in Cytochrome C Oxidase and Adenosine Tri-Phosphate

As we near 980nm, we approach the peak interaction of light with H2O in the body. Although some of the energy is also interaction in the hemoglobin and performing the same function as a 800 to 850nm laser, the bulk of the energy goes to creating thermal gradients in the H2O that increase circulation and blood flow. The increase in circulation allows the bodies natural healing process to accelerate. This is also the most popular wavelength for high-end pain control lasers and many doctors feel that 980nm system provide the highest level of pain control

Continuous Wave (CW)Versus Pulsing Pulsing is beneficial because it allows for more intense micro absorption of energy with less possibility of damage from excess heat or other effects The following statements are true when pigmentation is not a primary factor: Continuous wave energy is absorbed more rapidly in the tissues, and therefore is considered to be most appropriate for more superficial conditions and more permeable tissues. Pulsing is absorbed less rapidly with progression through the tissues and can therefore be more effective at greater depth and denser tissues.

Penetration of tissue mainly dependent on wavelength as a general rule higher wavelengths penetrate

further/tissue factors-fat,water content,bone pigmentation etc/power – higher power lasers penetrate further/size of the beam-wider beam deeper penetration due to decreased spectral reflectance Generally 810nm penetrates further than 980nm

LLLT-generally considered to be laser with power less than 500 mW with tissue penetration of around .5cm Class 3b HPLT-generally considered to be laser with power more than 1 W—up to 60 W with tissue penetration of greater than 4-5 cm Many of the laser studies were done with LLLT the reason is up to recently HPLT was not available and if so cost were prohibitive Now a number of studies are using HPLT and comparing it to LLLT and HPLT by itself and numerous case reports as HPLT is becoming less costly Examples of HPLT studies: Use of 10 W laser on epicondylitis Use of HPLT for whiplash Use of HPLT for chronic neck pain vs LLLT

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Continued Use of HPLT vs LLLT for back pain Use of HPLT for Myfascial Pain Syndrome Use of HPLT for post cardiac pain Several new studies are currently beginning Use of HPLT on Rotator cuff injuries Use of HPLT on Non specific low back pain Dosages for HPLT initial dosages 3000 to 6000 J first session from 6000 to 15000 J on subsequent sessions Review of advantages of HPLT increased depth of tissue penetration, increased power, decreased treatment times

Pulse vs non-Pulse Lasers there have been a number of studies, some show a difference between pulse and continuous wave laser therapy/also a number that show no difference, almost all were done with LLLT, Reasons for difference? target tissue, disease or non disease state, body composition pigmentation, power level More studies needed As of now, a few certain difference ie neurorehabilatation,may increase penetration depth, less heat on skin—more tolerable

Biphasic Response—to much can be bad ? a number of studies have shown a biphasic dose response the were almost all done with LLLT, only one done with HPLT-it was a study that looked at only one tissue observation and noted only at one time and healthy tissue involved, ie flawed study The theory - there is extended release of ROS(reactive oxygen species) that can cause tissue damage However, there are no individual case studies that show it with HPLT-talked with a number of providers –never seen it REASONS THAT IT MIGHT NOT OCCUR normal vs disease state level of oxidative stress current meds HPLT might overpower ROS response after a certain time tissue target

What to look for in a an office laser -power 10 W or more -cost-current—10000 to upwards of 25000 -wavelenght—810 vs 980 vs 810 and 980 -customer support Pros and cons of 810 Pros and cons of 980 Pros and cons of 810/980

Current uses of lasers anti-inflamatory wound healing tissue repair pain management increased immune respone improved vascular flow neurorehabilation muscle pain spinal disc and joint pathology/pain neuropathy dental pain/hypersensitivity neurological conditions –MS,stroke headaches

Examples and possible future directions acute ischemic stroke-if within 24 likely effective HPLT for depression-improved improved memory in multiple rat models ALS rat model-improved early motor function SCI rat model-contusion and hemi-section,showed increased function vs control group

Continued examples and directions Case studies—numerous ALS MS-very effective in mouse models HPLT for cervical disc herniations Increased muscle performance and recovery

Personal Observations and Notes Why I became interested in Lasers

friends animals treated by lasers friends treated by lasers Personal experience

LAST CASE STUDY QUESTIONS