Medicandus

Medicandus

Can we make whiplash less of a pain in the neck?

Once upon a time, not too long ago, ‘whiplash injury’ was regarded as a prototypical malingerer’s diagnosis. I can even remember an episode of the Brady Bunch where the dad ‘proved’ the plaintiff in a personal injury case (complete with massive neck collar) was a fraud by chucking his briefcase onto the floor so the faker would look round in surprise. At the time it seemed like a brilliant ‘gotcha’ but these days I would have a lot of sympathy with the collar-wearing guy. He might have been able to do that as a one-off movement when startle responses override normal movement patterns, but he was probably crippled by increased pain for the next week, and lost the case to boot without the chance for its legal merit to be tested by due process.

The key to understanding principle in managing trauma patients is to understand in detail exactly how they were injured. Body tissues have evolved to demonstrate fairly predictable biomechanical properties. They tend to fail in more or less predictable patterns. Watch any video compilation of ACL ruptures in sportspeople and you will quickly get the idea. This principle is very important in whiplash injuries, as the term refers to the mechanism of injury, rather than the body part or parts injured. This short video demonstrates the accepted biomechanical understanding of how these injuries occur, but it is very interesting that it doesn’t mention the structures that have prompted me to bring this problem to your attention.

Attempts to pin whiplash-associated neck pain down to a simple explanation have come up short repeatedly, which has led to some therapeutic nihilism in many circles. This NHMRC report from 2008 is typical of the genre. The evidence -based treatment consists of little more than encouragement to move the neck actively and ‘rub where it hurts’-type treatments covered by a fig-leaf level of good-quality evidence.

In more recent times, some useful progress has been made by new approaches focusing on tissue function rather than structure, and based on a much more sophisticated understanding of the biomechanics of the injury and how it can affect neck, shoulder and arm tissues. This one is a rather good, and readable summary of the newer stuff. This one specifically mentions a potential source of pain that seems to have been missed until quite recently - the cervical zygapophyseal joints (also known as facet joints).

Proponents of the ‘all in the head’ school argue that some combination of psychological factors or central sensitisation of the spinal cord and brain explains the whole problem, and that long after the injury, there is little pain actually generated in the neck. If they concede there might be a little, they argue that it is clinically irrelevant beside the importance of the central processes. They argue that the neck itself isn’t where the pain comes from, and we should focus out efforts on the spinal cord and brain to understand more.

Others (myself included) feel that an ‘all in the neck’ approach may still yield more progress, as peripheral input is probably the driver of the sorts of central changes that have been observed. The contribution of facet joints and soft tissues such as muscles and ligaments is arguably much more important determining outcome than has been recognised to date. It’s impossible to move your neck and stay active and think positively if the very movement you are supposed to perform creates severe pain.

With this background debate going on in the literature, I came across a very important paper this week. Here it is in full. The authors have serious pedigrees, particularly Gwen Jull and Michelle Sterling who are two of the most respected research academic physiotherapists working in Australia. The study makes a direct link between a procedure which reduces the nerve input from the facet joints in the neck (cervical radiofrequency neurotomy) and improved neck movement, with substantially reduced evidence of central sensitisation. It is a very rigorous and high-quality study from a methodological standpoint. It tends to confirm what many of us in the field have noted in practice, that so-called ‘poorly coping’ whiplash patients can make impressive gains in quality of life and reduction in their medication use if their neck pain can be reduced by a procedure. It should give hope to sufferers of chronic neck pain following whiplash injury that they may be able to get improved quality of life, even a long way down the track, if their pain is coming from dysfunctional or injured facet joints. Other studies report outcomes from cervical RFN that the better established conservative treatments can only dream of.

Access to cervical RFN is still very patchy within Australia, and many centres which provide it don’t do so within a broader multidisciplinary setting. These procedures might be effective in the medium term, but in the long term they will only be as good as the new movement patterns and muscle strength which can be developed afterwards. There is a huge effort needed to create integrated services which can perform the procedures and adequately rehabilitate people afterwards. But the prejudice and nihilism of years past is crumbling, and studies like this help to give it huge shove.

Disclaimer-I use cervical RFN to manage whiplash-associated neck pain as part of a comprehensive approach