There are some limitations to this study, including that almost all patients had disease at C5 or above, so whether these findings would still occur if patients were affected below this level remains unanswered.
However these are very interesting findings and raise many important questions; Could lung function be used as a marker of disability in CSM? What are the day to day implications for CSM patients - for example do CSM patients become more prone to chest infections? We will have to wait and see.
The are many different types of surgery proposed for the treatment of CSM. The main distinction is whether the surgery is from the front (anterior) or back (posterior) of the neck. A recent large scale study has found that there is no overall difference in their efficacy. (1)(2) However some recent research may have re - opened the debate by suggesting some subtle differences...
At present CSM research is largely based on functional scores. There are various different types, but typically they are designed to given an overall impression of a patients function.
Hu Ren et al have been looking at specific components of function, e.g. just arm recovery.(3) In their small study of 124 patients undergoing treatment at more than one spinal level, although they again confirmed no overall difference between anterior and posterior surgery, they did find that arm recovery may be better if patients underwent anterior compared to posterior surgery.
This is a small study with limitations, and should not be taken at face value at this stage. However the results are interesting, as they re-affirm the need to individualise the type of treatment offered patients. At present surgical experience and the type of pathology are likely to be the main factors in determining the type of surgery offered. But perhaps the exact disability and types of symptoms may be pertinent. With ever advancing methods of assessing CSM, this is an important future research question.
1. Fehlings et al 2013. Anterior vs Posterior surgical approaches to treat cervical spondylotic myelopathy: outcomes of the prospective multicenter AOSpine North American CSM study in 278 patients Spine (Phil)
2. Luo et al. Comparison of anterior approach versus posterior approach for the treatment of multilevel cervical spondylotic myelopathy. Eur Spine J.
3. Hu Ren et al 2016. Patterns of neurological recovery after anterior decompression with fusion and posterior decompression with laminoplasty for the treatment of multilevel cervical spondylotic myelopathy Clin Spine Surg
What the team from Taiwan did, was to identify all patients with CSM, and then to look at who went on to have a SCI. They also compared between patients who had had surgery and those that had not.
They found an overall risk of developing SCI of 0.2% per year. That means for every 1000 patients with CSM, 2 each year will develop a SCI. Although not directly compared this would be considered greater than the risk of those in the general population.
The group also went on to consider risk factors. They found that Men, CSM patients with OPLL (ossification of a specific ligament in the spine) but more interestingly perhaps, those that had not undergone surgery, were more likely to develop a SCI. They estimated a two fold increase in risk.
This is interesting data, particularly given we know so little about what happens in the longterm for patients with CSM, either treated or not. Whilst a two fold increased risk remains a very small risk, SCI is a potentially life threatening injury and paralysis is common.
1. Li-Fu Chen et al. Risk of spinal cord injury in patients with cervical spondylotic myelopathy and ossification of posterior longitudinal ligament: a national cohort study. Neurosurg Focus 40 (6):E4, 2016
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