PA as clinical tool
"Until now, we've mostly used PA as a diagnostic tool in the research setting," Haussler says, "but as veterinarians become
more familiar with the technology it has potential as a therapeutic monitoring device."
It can be used in practice for subtle or hard-to-localize problems. "Affected horses often are stiff, but when PA was used
as a diagnostic tool, we were able to localize the pain to one side and one vertebral segment. Without the tool, you couldn't
really do that.
"There are a lot of horses that seem to be painful over their entire back, and if you take the time to map out the painful
area, you find that the pain is localized maybe to one area or to specific muscles or bony landmarks," Haussler explains.
"It helps us as a clinical tool to identify whether a horse has more of a muscle injury that is causing the back pain,
or a bony-related problem, such as impinged dorsal spinous processes or possible osteoarthritis of the synovial articulations."
The benefit of PA is in localizing the pain and grading its severity, but more accurately than the subjective grades of mild,
moderate or severe.
There are other applications for PA to quantify limb pain, but more clinical research and case studies are needed.
"I talk about the potential clinical applications of PA in horses whenever I get the chance," Haussler says. "However, I do
not know how common it is used by others."
PA is being studied by Willem Back at Utrecht University and the University of Queensland in Australia to evaluate sacroiliac
problems and possible integration and assessment of physical-therapy techniques.
"With all things new and different, you need to see what its strengths and weaknesses are," Haussler says. At Utrecht University,
researchers are evaluating repeatability between days and between examiners.
"It's probably not a tool that every practitioner has in the back of his or her truck, but if you're interested in looking
at back problems, or if you're really serious about evaluating your treatment effectiveness, then I think that it is a tool
that practitioners should start looking at."
Other methods studied
In addition, equine practitioners are looking at other methods to best diagnose and treat different types of back problems.
"We need to come up with better tools, similar to PA, to assess muscle spasms, back stiffness and poor performance objectively,"
Haussler concedes. "PA is one tool, but we're always trying to find new ones that can give us numbers or objective data rather
than subjective assessments of back pain or poor performance."
Other methodologies being examined to improve diagnosis of equine back problems include improved radiography, diagnostic local
anesthesia, thermography and diagnostic ultrasonography.
"Hopefully, in the near future, we will be able to do MRIs or CT scans on the entire horse, and not just on its head or its
upper neck," Haussler says. "If we can approach equine back problems using several different diagnostic or therapeutic techniques,
then I think we're going to be much more effective in helping horses with back pain."
Kane is a Seattle author, researcher and consultant in animal nutrition, physiology and veterinary medicine, with a background
in horses, pets and livestock.