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Pointing light at soft tissue: clinical applications 67

have said, if you treat a chronic wound with 4–5 achieve a biological effect, and steroid treatment
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J/cm and after 1–2 treatments (in 24–72 h) it may also change that threshold.
looks the same, stimulate it more. You can use a • Endocrine disorders: diabetes, Cushing’s, hypo-
higher dose (more J/cm ), a higher power density thyroidism, and Addison’s can be quite a challenge,
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(more W/cm ) or both. I tend to maintain power especially Addison’s.
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density around 0.2–0.5 W/cm but increase dose • Paraneoplastic syndromes can dramatically
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(by 30–100%) by increasing treatment time when alter wound healing – usually other symptoms are
I want to stimulate a wound more. Underdosing is present.
much more common in LT than overdosing; just • Nutritional deficits: an insufficient caloric and/or
don’t try to give that extra energy too fast (too protein intake will affect wound healing. Some situa-
much power) or over too small a spot (too much tions, such as burns, post-ops, and severe infections,
power density). require a higher protein intake. Vitamins A and E,
• Consider other factors that may interfere with the zinc, copper, magnesium, and omega-3 fatty acids
healing process: I suggest you read the “Guidelines are especially relevant to proper wound healing.
to aid healing of acute wounds by decreasing imped- • Immune and/or infectious diseases, such as leish-
iments of healing” [217] for a more extensive review of maniasis (which is unfortunately very common in
local and systemic factors affecting wound healing Southern Europe) will have an effect. This does
and the level of evidence behind them. The Wound not mean you will not achieve wound closure in an
Healing Society categorizes local factors into immune-suppressed patient, but it may take longer.
wound perfusion, tissue viability, hematoma and/ In an experimental study with hydrocortisone-
or seroma, infection, and mechanical factors. LT induced immunosuppressed rats, LT improved
improves blood supply, oxygenation, and metabo- wound closure and decreased inflammation. [48]
lism, which affects both perfusion and viability. LT Interestingly, 10 Hz seemed to work better than 100
should not be used if there is active bleeding, since Hz in these rats. Leishmaniasis patients may expe-
we would increase hematoma, but after bleeding is rience more challenges when it comes to wound
controlled it can help resolve the hematoma faster, healing, but in my experience LT is very likely
decrease the risk of seroma formation, and decrease to help them too when it comes to wounds and
bacterial counts in infected wound and burns. pododermatitis.
Mechanical factors such as licking or other forms
of self-trauma to the wound are very common in 7.3 Lick granuloma
small animal practice, much more than in human
medicine. Many owners report their that animals This is one of the conditions in which you often have to
pay less attention to the wound after LT, but we still significantly increase the dose, and it is not uncommon
need to find the best way to protect the wound while to end up using 20–30 J/cm , especially in the more
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keeping the patient comfortable. chronic and hyperplastic lesions. Nevertheless, some
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patients respond to 4–5 J/cm , which is a usual dose for
If local factors seem to be under control but the chronic wounds. You can use 2–4 W. Do not hesitate
wound is not properly progressing, consider systemic to broaden the treatment area and treat a 5 cm margin
factors that may be contributing to this delay – these (Table 7.2).
are just a few. The etiology of lick granulomas is multifactorial, and
often not even diagnosed. Behavior disorders, atopy,
• Steroid treatment affects wound healing, whether folliculitis, and other causes are considered, but some
you laser the wound or not. But LT will help coun- animals enter this cycle because a painful condition
teract those inhibitory effects of steroids. [118] One is present, in the granuloma area or at a distant site,
paper described no effect of LT in steroid-treated and this should be ruled out and treated if diagnosed.
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rats, [137] but they were using 1–15 mW/cm , whereas Neuropathic pruritus and dysesthesia may also occur,
you will be using around 200–600 mW/cm most for example in intervertebral disk disease and nerve
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of the time while working with class IV devices root irritation. Investigate these as potential causes;
and wounds. You need a certain power density to if you think there is such a component, you need to

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