by M. Stewart
One of the most unusual things about CSM is what we call the “clinical radiological mismatch”. This means that there is no clear link between the clinical picture (the pain and disability that you feel, and the abnormal neurological signs we see in the clinic) and the radiological picture (what we see when we take images of your spine using X-rays and MRI). Some people can have very little abnormality on imaging, but have disability indicating severe myelopathy. Others can have major changes in their spine on imaging, which we might expect to give myelopathy, but have few or no symptoms.
It’s easiest to understand why mismatch is a problem using the example of a simpler condition. Imagine you have fallen onto an outstretched hand and come into A&E. We can examine you and establish that your wrist is painful and difficult to move. We take an X-ray and see clearly that you have fractured one of the bones in your wrist. This allows us to:
Here, there’s no mismatch – what we see on the images (normally) links directly to what we see at the bedside. Compare this to CSM. There’s nothing as simple and easy as a broken bone to look for, with numerous changes on imaging being potentially associated with myelopathy. Cervical spinal cord compression (seen on MRI scans) was thought to be one of the key imaging changes seen in myelopathy. However, just last month we talked about how most older people have spinal cord compression, but only one or two in a hundred have actual myelopathy (i.e. are ‘symptomatic’). As we have no definite way of spotting it on imaging, it can be difficult to diagnose myelopathy, decide when to offer surgery for it, determine how well our surgery worked or judge how the disease might progress. This is especially problematic as effective surgery depends on early diagnosis, offered too late and spinal cord damage may be permanent. With this in mind, it could be extremely useful if we could find imaging changes that only occur in people who actually have myelopathy (the ‘symptomatic’ group).
Fascinatingly, a group in Hebei Medical University China seem to have done just this. They have discovered several imaging changes that may distinguish symptomatic patients and could even predict the likelihood of myelopathy .
What did this experiment involve?
68 patients with cervical spinal cord compression were examined and divided into two groups. 30 had no signs or symptoms of myelopathy (the ‘asymptomatic’ group) and 38 were symptomatic for myelopathy (nerve damage, changes in reflexes, muscle spasms etc). The researchers then looked at the patients’ X-rays, CTs and MRI scans and tried to identify any differences in imaging between the two groups.
What were the results?
Three types of imaging change were found to be significantly more common in the symptomatic group.
What might this mean?
This could be a chance to overcome the clinical-radiological mismatch in CSM. Looking out for these three imaging changes could help us identify those patients who actually have myelopathy and are in need of surgery from those who don’t, making sure we operate in time. Furthermore, they could help us confirm when asymptomatic patients have progressed to a symptomatic stage. Potentially, they could even help us see how well our operations have worked, by seeing if the changes are reversed after the procedure!!
What were the weaknesses of this study? What could be next?
The main weakness here was the small number of patients used. The next step is to continue it in other hospitals, to see if the results are supported or if other important imaging changes can be found. However all of this seems extremely promising for the future of CSM, especially in terms of early diagnosis and choice of treatment!!
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