Contributed by Ren Houyoux, LVT
When performing a laser therapy treatment, selecting the appropriate treatment head for the intended technique as well as the selected power is imperative. When treating using an on-contact method, only the deep tissue applicators (also referred to as “massage ball” applicators) are appropriate to use. The two flat “cone” attachments can NEVER be used with this technique, as it is not their intended method of delivery and could cause harm to the patient or damage to the treatment head itself – their use is restricted to an OFF-contact technique.
Benefits of Treating On-Contact
There are several advantages to treating with an on-contact technique. First, making direct contact will reduce the amount of light reflection off the skin’s surface and maximize penetration into the deeper target tissues. Any time we operate off-contact, a certain amount of natural reflection from the surface of the skin and the hair coat occurs.
Second, by making contact and applying a moderate amount of pressure (similar to a massage), we are able to blanch the tissue and reduce the amount of incidental light absorption by hemoglobin in superficial capillaries, etc, thus further optimizing photonic saturation of deeper target tissues. Additionally, this massage-like technique not only feels good to the patient, it also encourages local blood blow.
Lastly, applying a combination of on-contact treatment while applying a moderate amount of pressure will compress superficial tissues (such as fat), bringing the target tissues closer to the laser’s point of emission. A myriad of deep musculoskeletal conditions can and should be treated with an on-contact technique, including osteoarthritis, sprains, fractures, tendinopathies, cystitis, asthma, and pneumonia.
Ensuring Adequate Dose Delivery
In order to ensure complete saturation of the target tissues, the hand piece must be held perpendicular to the tissue surface. Any time we operate at any other angle than perpendicular (90⁰), the beam spot will be distorted, reflection from the tissue surface will increase, and there is an overall uneven distribution of light to the tissues.
In addition to treating perpendicularly, it is also important to remember to treat all limbs/extremities with a circumferential approach (from 360⁰) so as to fully and evenly illuminate the target tissues and structures.
Knowing Your Equipment
We should also be mindful of the parameters specific to each attachment head. The two attachment heads meant for an on-contact technique (also called “massage ball” or “deep tissue applicator”) each have their own power applications and beam divergence (widening). While the large deep tissue applicator can be used at any power and has a divergence of 3⁰, the small deep tissue applicator should NOT be used when operating over 3 watts, and it has a divergence of 13⁰.
Thus, we should select the appropriate treatment head as per the specifics of the case and should be able to “visualize” tissue exposure. So, while the large massage ball has a larger beam spot (at the surface of the lens) than the small massage ball, the latter has a more pronounced beam divergence (widening) as the laser gets further away from the hand piece.
That being said, the deep tissue applicators may be used with an off-contact approach when the situation allows. The beam of the large deep tissue applicator only diverges at a 3⁰ angle, meaning the beam itself remains highly collimated. This high-degree of collimation is ideal when performing intraoperative treatments when we cannot make contact with sterile tissues. Thus, a very specific area (such as a cystotomy incision, anastomosis, enterotomy, gastrotomy, etc.) can be treated from a short distance without compromising sterility.
Maximizing Patient Comfort
Part of deciding on a treatment approach (i.e. on/off-contact) also depends on the amount of sensitivity a patient displays. If a patient is extremely painful, it may be needed to start therapy with an off-contact approach and work our way up to an on-contact technique once we’ve attained a significant clinical (palliative) response.
Sometimes, a patient may seem sensitive when it may actually be a “startle” response when the operator makes initial contact with the skin. This startle response could also be from a temperature gradient (i.e. the treatment head surface may be cold). It is useful for the operator to make initial contact nearby, but away from the painful tissues so as to minimize or prevent this type of response. Making initial contact with a non-painful part also decreases the stress the patient will experience. For example, a geriatric cat suffering from lumbar spondylosis can be relaxed by using the deep tissue applicator as a massage ball on the neck just prior to moving to the lumbar spine and starting treatment.
It is also important to determine if the patient is hypersensitive to touch, temperature, or both, especially in cases in which the laser operator is treating for chronic pain. This is particularly true over boney prominences, and in areas of thinned skin, especially of the elbow and the stifle. In these patients, as well as in any patient with a wound in the treatment area, treating in an off contact manner may be necessary. A simple technique that can differentiate between patients objecting to physical contact and those sensitive to warmth is to attempt to “treat” with the laser off, that is simply applying gentle pressure with the massage ball treatment head. If the patient does not object to this technique, but displays agitation or signs of discomfort during treatment when the laser is on, adjustments may need to be made in turning the power down (usually in increments of 2W) and attempting to treat again, following proper guidelines on monitoring patient comfort as discussed in previous blogs.
Proper treatment head selection and delivery technique are of crucial importance with any photobiomodulation (PBM) treatment. Following manufacturer guidelines and recommendations for treatment head use ensures safe treatments and optimal results, and should thus be strictly adhered to.