Learn tips about Class IV laser therapy and other health related topics on the LightForce Therapy Lasers blog! Check back weekly for updated posts.
Contributed by Mark Callanen, PT, DPT, OCS
In Part 1 of this laser forum, we discussed the basic terms related to the physics of laser therapy. Here we will cover the significant role irradiance (power density) and dosage (energy density) plays in 3 concepts pertinent to photobiomodulation (PBM) therapy.
1. Higher irradiance allows more photons to be applied at depth for a given wavelength. Please refer to the image below for a visual representation of this concept.
This is important with regard to PBM as it is a threshold-phenomena. If sufficient light does not reach the injured target tissue, there will be no notable therapeutic change1. Higher powered lasers can help with this problem by providing higher photonic density at the skin which helps transfer proportionate levels of light to deeper tissues. This concept can be referred to as “therapeutic depth”. It is worth noting that this is a complicated topic that goes well beyond the scope of this article and that there are several variables that impact optimal tissue dosing.
2. When treating with a laser, it can be difficult to maintain therapeutic dosing levels when treating over large surface areas. This is because as the treatment area grows, so does the denominator of the energy density equation (J/cm2) which can dilute the dose of energy being applied if higher joule levels are not applied proportionately. Having more laser power to utilize makes this adjustment easier for the clinician. Note: (J = W x s).
The graphic below helps clarify how adding power impacts treatment time for a given energy density and a given area.
In summary, adding power to the energy equation can significantly reduce the time needed to apply a therapeutic PBM dose of light.
3. The final important clinical factor that higher irradiance impacts is with regard to pain relief. More specifically, analgesia that can be created at peripheral sensory nerves when higher irradiances are applied to C and A-delta sensory nerves. It has been shown that when > 270 mW/cm2 is applied to these nerves, neuroplastic changes take place within 2-3 minutes at the peripheral nerve that slows the conduction rate of the pain signal3. This physical change to the nerve quickly reduces pain4.
Additionally, it has been shown that an inhibition of nociceptive action potentials takes place when higher power densities are applied to nerve tissue. Specifically, a 30% neural blockade has been shown to start 10-20 min after treatment, which further reduces pain perception4.
There are other longer lasting benefits that PBM provides with regard to reducing inflammation around damaged tissue, but this is a mechanism of healing that is not unique to treatment with higher irradiances1,2,4.
One final note with regard to safety, treating with higher power density does increase the risk of thermal effects on surface tissue as more heat is produced. Using ideal wavelengths that minimize photonic absorption at the skin and utilizing appropriate treatment heads that help manage surface heat is an important component to consider when treating with Class 4 lasers.
LightForce Therapy Lasers influence® Technology helps to easily manage these factors through a combination of patented software and hardware features. The patented large massage ball and large cone applicators play an integral role in delivering high powered treatments that are safe and comfortable to the patient.
If after reading this you still have questions about the effectiveness of higher powered lasers, please watch this informative animation, or contact us directly at firstname.lastname@example.org.References
1. Huang, Y. Biphasic Dose Response in Low Level Light Therapy. Dose Response. 2009; 7(4): 358–383.
2. Bjordal JM, Couppe C, Chow RT, Tuner J, Ljunggren EA. A systematic review of low level laser therapy with location-specific doses for pain from chronic joint disorders. Aust J Physiother. 2003;49:107–16.
3. Holanda, V.M. et al. (2017) The Mechanistic Basis for Photobiomodulation Therapy of Neuropathic Pain by Near Infrared Laser Light. Lasers Surg Med. 2017 Jul;49(5):516-524
4. Cotler, H et al. The Use of Low Level Laser Therapy (LLLT) For Musculoskeletal Pain. MOJ Orthop Rheumatol. 2015 ; 2(5).
Contributed by Mark Callanen, PT, DPT, OCS
There is often confusion in the medical field when clinicians research the topic of laser. At the center of the confusion is power and its relationship to lasers’ effect on tissue, which is referred to as photobiomodulation (PBM)1.
To understand the role of power, there needs to be an understanding of its relationship to laser dosing, penetration, and how higher power lasers impact tissue(s). This two-part blog is intended to clarify some of the key terms related to the physics of laser therapy and expound on the clinical implications of treating with higher power density. But first, let’s look at a few key terms:
Photons: When any form of light is introduced to tissue, small “packets” of light called photons are emitted from the light source. At any specific wavelength of light, every photon contains exactly the same amount of energy. Think of a photon as the building block of light.
Energy: The total energy applied during treatment is the addition of all the individual photons that are emitted over a predefined period. The International System of Radiometric Units uses the joule (J) as the unit of energy to measure this property. Joules are the product of power and time.
Power is measured in watts or milliwatts and plays a key role in the total energy that is applied to tissue. Total energy (joules) by definition is the product of power (watts) and time (seconds). (J = W x s).
Therefore, increasing the power of a light source will deliver more joules of energy per unit time to a target. This plays a significant role in delivering photons to deeper tissues. A simple way to envision its importance is to think about how much light a 10 W bulb produces in a dark room vs a 100 W bulb. The more wattage the bulb emits, the more light will be present in the room. This analogy is similar to the wattage of a laser that is applied to the skin – the higher the wattage, the more “light” that is delivered into the tissue (at a given wavelength).
Now that you have more clarity on power and energy, the last important characteristic to understand is the concept of density with regard to these two terms. Density brings into account the area that is treated, and will be noted in cm2.
Power Density (W/cm2): This term describes the intensity of the light, or its “brilliance” and is referred to as irradiance in the literature. Irradiance impacts the number of photons that will be applied at depth for a given wavelength and is directly related to the heat that will be produced at the surface when a light source is applied.
Energy Density (J/cm2): Commonly referred to as fluence, it is synonymous with dosage when defining PBM treatment parameters. It defines the total amount of energy that is applied per unit area and can be influenced by increasing the time of the treatment and/or the power that is being applied from the light source. (J= W x s).
To summarize, these terms all play a role in understanding the basic physical properties of light and how it impacts PBM. With this knowledge in place, Part 2 will discuss the benefits of higher power laser therapy as it relates to 3 key treatment attributes. Stay tuned!
References: 1. Anders JJ, Lanzafame RJ, Arany PR. Low-level light/laser therapy versus photobiomodulation therapy. Photomed Laser Surg 2015;33:183–184
Contributed by Mark Callanen, PT, DPT, OCS
Healthcare is no different than most other businesses when it comes to customer satisfaction. If you want to retain and attract more patients, you need to focus on improving customer experience. Helping patients feel better quickly is a key component to customer satisfaction that leads to more successful practices with high patient retention and steady growth.
It may seem obvious that better treatment outcomes would increase practice traffic, but by pin pointing the exact marketing mechanism responsible, that is, the power of word of mouth marketing, you can maximize your patient growth potential. The Net Promoter Score (NPS) is a tool designed to quantify this phenomena: “NPS is an index that measures the willingness of customers to recommend a company’s products or services to others. It gauges the customer’s overall satisfaction with a company’s product or service and the customer’s loyalty to the brand” (Wikipedia).
So, if your goal is to increase customer loyalty by improving your staff’s ability to reduce pain complaints quickly, you should consider investing in a deep tissue therapy laser. While most clinics promote a variety of manual techniques and modalities to help with pain, few offer deep tissue laser therapy (which promotes lasting pain relief for both deep and superficial musculoskeletal complaints).
LightForce Therapy Lasers can help a practice stand out to patient populations that are currently not having their pain needs met. How big is this market? Pain related diagnoses including low back pain, osteoarthritis, and general joint related disorders account for over 57% of primary physician care visits annually2. Laser therapy (also known as photobiomodulation therapy) can help with many of these diagnoses. This is significant as many of these patients are looking for treatment options that don’t include meds or surgery.
While it requires time to educate patients on the benefits of a newer technology like photobiomodulation, it is highly beneficial to both the patient and the provider to do so. A patient’s decision to consult a health professional is based on a complex mix of social and psychological factors1. Fear and anxiety about their condition play a significant part in this equation. Reducing pain quickly with a modality that focuses on reducing musculoskeletal pain will help reduce patient anxiety that the problem is something more sinister. In this way, laser technology can serve as a powerful tool to get immediate patient buy-in to a plan of care and reduce their overall levels of fear. This should benefit their overall outcome on multiple levels.
By changing a patient’s pain status with this kind of “wow factor” and giving them a clear understanding on how you plan to attack their painful musculoskeletal condition, the impact this message will have should be quantifiable via the facility’s NPS. More importantly, this type of therapeutic alliance will turn your patients into the facility’s best marketers as they will want to tell friends and family about their positive experience.1. Campbell SM and Roland MO. Why do people consult the doctor? Family Practice 1996; 13: 75-83. 2. Why Patients Visit Their Doctors: Assessing the Most Prevalent Conditions in a Defined American Population St. Sauver, Jennifer L. et al. Mayo Clinic Proceedings , Volume 88 , Issue 1 , 56 – 67