By Renaud Houyoux, CVT, LVT, CVDT, VNA, LSO, CCRP

The advent of photobiomodulation therapy (PBMt) as a medical modality has proven itself in the veterinary field, but we are all too often reminded that some conditions can be extremely challenging to treat regardless of the modalities being considered for a specific case presentation. A wise laser operator will recognize this and keep it in mind as we develop goals and expectations for each case. This, in turn, will drive the treatment design and delivery techniques best applied. Other than death, taxes, and a partial CCL progressing to a full CCL, there are few guarantees in life. When used appropriately, PBMt is a tremendous asset in establishing a pain management protocol which also induces active tissue healing for a myriad of conditions. Having recognized the expected and potential hurdles each case brings forth, there are several “usual suspects” which come to mind as the more challenging cases to approach. In this first part, we will look at some of these “usual suspects.” Further presentations will be addressed in the second portion of this discussion.

Degenerative myelopathy (DM) is a particularly devastating disease, as we currently have very few effective options in dealing with this incurable condition. Our goals would primarily be slowing disease progression, preventing an active decline, and managing any secondary painful conditions that may also exist. As with any other situation where tissue dysfunction is occurring, the earlier we start treating the better outcome we can hope for. We have seen very encouraging results when we start treating these patients while still in stage I when combined with good physiotherapy. Typically, a patient will progress from the pelvic limbs and then move on to the thoracic limbs as the disease is ascending. The time frame can range from 6-9 months for progression from stage I to stage II disease, but we know that this will invariably occur. When adding PBMt to an intensive rehabilitation therapy program for DM patients, we have seen evidence of delayed disease progression and time to non-ambulation as well as anecdotally maintained good quality of life as long as a comprehensive medical care plan continues to be applied. Here is a link to recently published research which supports using the laser as part of an intensive physiotherapy protocol for these patients.

PBMt is always best applied as an adjunctive modality to a comprehensive treatment plan which incorporates standard of care, and this is especially important with DM. For optimal results, it is imperative that the client be instructed as to environmental modifications and at-home care directed to face this condition head on. We can certainly guide the client to provide an environment more easily navigated by the patient whose mobility has been compromised such as placing rugs over slick hardwood floors, applying basic massage techniques, and improvised land exercises which mimic in-clinic rehabilitation. Hydrotherapy is another easily-replicated modality which can be modified to be applied at home with smaller patients. We can fill a bathtub or children’s pool up to a certain level for smaller patients and give them the benefits of assisted standing and balancing or walking with hydrotherapy. Pillows and couch cushions can be considered in a similar fashion as wobble boards and peanuts – as long as the patient can safely be ‘challenged’ in an assisted manner without being put in potential danger from a fall. Appropriate nutrition is also paramount to promote systemic well-being and help combat any muscle wasting. The objective here is to introduce the concept of multimodal integration, and the above is a succinct list of supportive aspects of home care that can be beneficial with these cases.

When specifically looking at PBMt treatments combined with physiotherapy for DM, evidence has shown that in order to get the best clinical response, a higher fluence (dose in J/cm2) and irradiance (W/cm2) is optimal. An on-contact delivery technique should be directed along the spinal cord and paraspinals along the entire thoracic and lumbar spine. The savvy laser operator will be careful not to apply too much pressure when passing over the dorsal spinous process with patients who have undergone some muscle atrophy, as this bony prominence can become quite sensitive. If we are to expect optimal results, a frequent treatment schedule must also be adhered to. Typically, starting three times weekly promotes the best response when first attending to these cases. Once the patient is enrolled in a good physiotherapy and laser treatment routine, we must continue with an ongoing maintenance treatment frequency. Unlike osteoarthritis, it is best to continue ongoing long-term maintenance treatments delivered at a twice weekly interval. Decreasing treatment frequency further than this point has been shown to be insufficient for ongoing prevention of active decline. For a more in-depth look at both in-clinic and at home rehabilitation for these patients, the following webinar will help the attending veterinarian and medical team (click link). 

Feline Stomatitis is another devastating disease that can be challenging to deal with. This disease will typically have systemic repercussions, which can quickly lead to our medical options being reduced if the client is not committed to assertive and ongoing care. It would be best if we could initiate therapy as early as possible, but unfortunately we usually see these patients present after multiple options (such as dental extractions and oral surgery) have been exhausted. PBMt will greatly help reduce the oral pain and assist the body’s ability to heal these inflamed tissues. In turn, we can usually alleviate one or more symptoms secondary to the disease such as dysphagia, ptyalism, bruxism, head shyness/aggression, decreased social interaction, weight loss, and hydration. Treating these patients is a perfect example of how the laser operator needs to interact with the patient in a non-threatening manner, as they will likely be reluctant at first to any manipulation of the face and head due to wind up. The savvy laser operator will adjust their treatment delivery technique so as to build trust with the patient who in turn will then allow treatments to be carried out.

This is where technician ingenuity (such as distraction techniques the patient can respond to due to their heightened sense of smell) can be really beneficial in being able to deliver these treatments without undue stress to the patient. Examples include the use of catnip on the substrate/bedding the patient is placed on, placing a heating pad under the substrate to provide a warm and relaxing spot for the patient to settle down on, and dabbing a finger over some enticing food smell (like the chicken breast sitting in the fridge that we know we’ll never get to eat) and then dabbing this over strategic places either on the substrate (or even the client’s hands/wrist). Never underestimate the benefit of using feline pheromone sprays or diffusers, as some cats are very receptive to these. Granted, not all patients will respond to the same degree, but it is a valid thought to entertain.

Depending on case history and presentation, the initial induction phase will likely need to be delivered off-contact. This may change as the patient becomes desensitized. If the latter does occur, it is recommended to go with the grain, especially when passing over the whiskers which are every sensitive. The goal here is to illuminate the entire oral cavity, including all dental arcades and hard/soft palate structures. Thus, a circumferential delivery technique must be applied, as well as illuminating the intermandibular space. Treatments can be delivered either via an intraoral or extraoral approach. In a perfect world, both should be done for full illumination of the oral mucosa, but it is unlikely a cat will willingly open their mouth unless there is some kind of sedation or anesthetic being applied as well. The laser operator will remain mindful of all these factors and mold the treatment delivery technique to provide a clinically effective treatment while at the same time minimizing patient stress.

Here is an example of an intraoral treatment being performed (click link). Since we are operating near the eyes, we must protect them from the laser beam. This can be done by using either laser-rated lenses or placing a cloth over the patient’s eyes and securing it in place with digital pressure.

We don’t pick them, but we must treat them. All of these case presentations can be quite complicated in nature and challenging to respond, and we must be prepared for that. At the same time, the attending veterinarian must set reasonable expectations and have precise goals for each case so the client is on the same wavelength as we course through treatment phases. Unfortunately, when a client has limited financial resources or when their ability to come in are less than ideal, these obstacles will greatly impact the patient’s glide path of response to therapy. In any setting, the therapy laser should be used as an adjunctive modality to standard of care. The use of PBMt does not replace the need for (and benefits of) widely accepted modalities such as pharmaceuticals, surgical intervention, physical rehabilitation, etc. Granted, we need much more research in multiple areas of the modality, but it is valid to say that we now have powerful units of appropriate therapeutic wavelengths which (when used in accordance to the knowledge base we have gathered over the past few decades) have a much more broad ability to effectively treat even the more challenging conditions. In part two of this blog, we will look at some other challenging case presentations which should still be candidates for PBMt.

Polyarthritis can be especially difficult to address due to several factors. This condition usually occurs with geriatric patients who thus have a decreased ability to physically respond to medical modalities than their younger counterparts. Keep in mind that more complex comorbidities may also come into play when dealing with systemic medications. With multiorgan involvement, it may not always be appropriate for a certain medication to be used depending on the drug pathway and which organs are affected. Depending on the number and locations of the joints affected, there is usually a very dynamic compilation of various compensatory mechanisms that patients will naturally use. To complicate things further, these sites of compensation will likely change as the patient improves and their kinematics change.

Thankfully, there are multiple protocol selections from which the operator can choose to address conditions such as arthritis, pain/trauma, and edema/swelling. To compound things even further, the laser operator needs to be familiar with the anatomy of each site being treated, as well as any other biomechanically-associated sites secondary to these. These cases may require even experienced operators to review their A&P notes since not everyone has to deal with these structures on a regular basis. Examples would include the iliopsoas and pectineus, which are more often assessed in a rehabilitation setting than in a general practice. Consider the patient that comes in with a markedly kyphotic stance: Not only do we have to address this site, but they are likely to be weight shifting forward, thus increasing load on thoracic limbs and decreasing the load on pelvic limbs. Treating multiple sites at the same time will require the operator to be skilled in accurately assessing the patient’s overall glide path of response to therapy, as well as assessing each site individually. The wise laser operator will remain flexible in the treatment design and delivery as per the patient’s glide path of response to therapy as these changes occur. Further supportive information on treating chronic conditions can be found here (click link).

The dreaded acral lick granuloma (ALG) can also be one of the more challenging case presentations we have to contend with. Due to the chronicity of these cases and amount of tissue planes involved, these will require patience and consistency in order to be treated effectively. While it is a challenging condition to treat, we can expect substantial improvement when treatments are consistently applied as an adjunct to standard of care. It is important that the appropriate diagnostics are used in these cases, as they can help rule out the etiology of the granuloma. Simple diagnostics such as a fine needle aspirate and radiographs can quickly give the attending veterinarian a much clearer picture from which an appropriate treatment plan can be formulated. For example, a radiograph could show an underlying early osteosarcoma- this would greatly impact the diagnosis, and thus the treatment recommendation. There is also evidence that these cases involve a certain amount of psychological changes with these patients. Data suggests that with these chronic cases, there is a serotonin release which reinforces this self-soothing mutilation (similar to OCD with humans). This is a prime example as to how PBMt is always best applied as an adjunct to standard of care.

A thorough pain exam must always be performed, regardless of condition, and it proves to be very important in this setting. The ALG could certainly be a displacement behavior for pain which originates in another location (like the neck or back), so it is crucial the pain exam incorporates this area to assess the possibility for radiating radicular pain. Oftentimes, treating the neck and other reactive spinal sites proves to be beneficial. Consider the pain pathway, and specifically the spinal intumescence innervating the affected limb as we can address the pain pathway at the step of modulation in the dorsal horn of the spinal cord. For best expectations to be met, PBMt treatments should be assertive if we are to expect reasonable expectations. The laser operator must lase not only the lick granuloma itself, but be sure to make a full beam cross over into the healthy tissue periphery simultaneously to enable the body to respond as effectively as possible. In a similar fashion to degenerative myelopathy, this condition will require a higher fluence than other protocols in order to enable an optimal tissue response in remodeling. Ongoing commitment to treatment must also be part of the plan if we are to expect significant and lasting changes.

Hospice/end of life care is as challenging to treat medically as it is to deal with emotionally. No amount of time in clinical practice makes this situation easier to deal with- it just gives us a better skill set and muscle memory to provide the last medical care we can give to a terminal patient. When options are reduced, we must in turn show some flexibility that would not apply to cases where we are seeking a curative result. For example, the terminal patient who has a confirmed malignancy comes to mind. Again, setting precise goals and expectations is crucial with these cases. If our focus has changed from curative to palliative then we must apply the same flexibility in the way which we use various modalities. When this terminal patient presents and the client has decided that they want to focus on a pure pain management plan instead of a curative plan of action, the laser can again be quite useful as an adjunct to this final treatment philosophy. We will not walk away from our patients, especially in their time of greatest need. We know the inevitable will come regardless, but we will not sacrifice quality of life for quantity of life. So, if this pain relief and maintaining their dignity and quality of life is the last thing we can do for a patient, it is our Hippocratic duty to show flexibility for the benefit of the patients entrusted to our care and medical expertise.

Again, we do not pick them, but we must treat them. All of these case presentations can be quite complicated in nature and challenging to respond, and we must be prepared for that. At the same time, the attending veterinarian must set reasonable expectations and have precise goals for each case so that the client is on the same wavelength as we course through treatment phases. Unfortunately, when a client has limited financial resources or when their ability to come in is less than ideal, these obstacles will greatly impact the patient’s glide path of response to therapy. In any setting, the therapy laser should be used as an adjunctive modality to standard of care. The use of PBMt does not replace the need for (and benefits of) widely accepted modalities such as pharmaceuticals, a surgical intervention, physical rehabilitation, etc. Granted, we need much more research in multiple areas of the modality, but it is valid to say that we now have powerful units of appropriate therapeutic wavelengths which (when used in accordance to the knowledge base we have gathered over the past few decades) give us a much more broad ability to effectively treat even the more challenging conditions.