Research has highlighted a lack of evidence to support the usefulness of taking neck X-rays in pre-purchase examinations (PPEs).
A new paper by Royal Veterinary College (RVC) researchers has reviewed findings from previous studies on cervical X-rays, to answer whether they should be included in PPEs. The researchers said neck X-rays are more frequently being requested in vettings – but concluded that current evidence suggests “most findings present on cervical radiographs acquired at PPEs are of unknown or low significance in a clinically normal horse” – and there is “little evidence to support these as part of a PPE”.
It was also found that there is “minimal evidence of the progression of subclinical abnormalities found in cervical X-rays and their future impact on performance”.
Rupert Freddie Dash, lead author and RVC staff clinician in equine diagnostic imaging, told H&H as radiologists his team is often asked to look at PPE X-rays and that the neck “can often be an area that is quite tricky for us”.
“We find that sometimes, due to no fault of the vet taking the X-rays, they can be of lesser diagnostic quality than, for example, limb X-rays. If they are of reasonable quality, even then the findings can be quite difficult to interpret, so we thought it would be a good idea to review all of the evidence and see whether these are worthwhile X-rays to be taking,” said Dr Dash, adding that although the neck is a well-researched area, there is limited research around PPEs in general and on this issue.
“There’s almost no evidence that will tell us if we find something [on a cervical X-ray] in the PPE, how likely that is going to inhibit or reduce the horse’s performance.”
The paper also addressed the difficulties of cervical X-rays being taken in an ambulatory setting such as at someone’s yard, as portable machines are not as powerful as those used in a hospital. This means the images are “often underexposed”, which can “reduce image quality and hinder thorough evaluation”.
Dr Dash said a portable X-ray machine is more suited to limbs, so “perfectly diagnostic” images can be obtained.
“In my opinion there is still a place for X-rays of the limbs in PPEs,” he said. “There is still relatively limited research about how findings will go on to affect performance, however there is more research than on the neck, and vets may have more depth of experience to draw from with issues relative to the limbs.”
Dr Dash said that when it comes to PPEs “there is more evidence currently that a physical exam of the neck is more valuable in terms of predicting if there’s an issue”.
“Vets should palpate and manipulate the neck, including doing tests that may involve getting some feed and making sure that the horse can reach its flanks. I would say that would be more useful than radiographs,” he said.
Lucy Grieve, the British Equine Veterinary Association’s projects officer, told H&H that X-rays are very common now in PPEs, but buyers “should beware of their limitations”.
“At one end of the spectrum, there is clear evidence that deviations from the normal in neck and back X-rays are of no predictive value for future soundness or athletic potential, where the PPE and history have not raised suspicions,” she said.
“At the other end, some abnormalities seen on limb X-rays will have a significant predictive value – but buyers should remember that there are still many deviations seen in limb X-rays that are not indicators of future problems.”
Ms Grieve added that misjudging the significance of abnormalities seen on X-rays alone “can and does result in many sales falling through unnecessarily” – and advises owners to discuss any findings with their vet.
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