Response to Laser Therapy
A Case Study
Keith A. Bailey, DVM
Laser therapy has been found to increase cellular respiration and enhance neovascularization as well as reverse inflammatory processes, hence accelerating healing. A variety of wavelengths between 600 nm and 1100 nm have beneficial effects on tissue. The lower end of that spectrum is more useful superficially while the higher end can penetrate deeper tissues as well, with those between 700 nm and 800nm having less benefit.
This case involved the use of the Companion® Therapy Laser by LiteCure. It operates at 980 nm wavelength and is variable in power from one to ten watts. This is a Class IV laser and, as such, must be handled properly, with all the laser safeguards outlined by the American National Standards Institutes in the documents, ANSI 136.1 and ANSI 136.3. More on safety and training, as well as available publications may be found at www.laserinstitute.org.
Craig:
Craig, a three-year-old male Mastiff weighing ninety-seven pounds, presented with right forelimb lameness. It had appeared suddenly, two days earlier, with no known incident of trauma. Upon examination it was noted that there was a non-weight-bearing lameness of the right forelimb. Carpus was knuckling under and elbow carried low. Limb was edematous and painful from the elbow down. Deep pain was present but there was no withdrawal response.

Radiography revealed only soft tissue involvement.


The limb, from the shoulder to the carpus, was treated with 2000 Joules of energy at eight watts continuous wave. Two days later his demeanor was much better. The limb was still edematous but there was no pain on manipulation. He was still dragging it and there was no withdrawal response.
At this time the same treatment regimen was applied. On day four, the edema had nearly resolved and he was not painful. Other than the motor deficits, he acted and appeared normal.

A slightly different approach was taken at this time. We treated only the subscapular region, using the massage ball head, which allows deeper delivery of energy while massaging the tissues and placing the limb through passive movements. Ten watts of power and continuous wave were used. The delivery was aimed all the way around the perimeter of the scapula, from the axillary region to the dorsal midline. Gentle pressure was maintained as the tissue was massaged.
Seven days later (day eleven) Craig was presented for evaluation. He was using the limb with barely any perceptible limp. All motor and sensory function appeared to be intact on examination and his owner reported that their lives had returned completely to normal.

Radial nerve paralysis is one of the most common forms of nerve injuries in dogs. Avulsion of some of the nerve roots of the brachial plexus is a much worse scenario and the two may be difficult to differentiate.
The degree of damage and prognosis for recovery depends on which form of paralysis occurs. The first form is called neurapraxia and holds the most favorable chance of full recovery. In this case, the fibers have been tweaked or stretched but not ruptured. Often, deep pain remains while motor and tactile sensory functions are diminished or absent.
Axonotmesis is the second form. Here the axon and myelin sheath are damaged but the connective tissue remains intact, allowing regeneration of the axon distal to the injury. This, too, may allow for recovery but holds a less favorable prognosis.
Finally, neurotmesis involves complete severing of the axon, myelin sheath and supporting connective tissues. Prognosis here is poor and amputation may be the only option.
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