by A Badran
Our ambition therefore was to look at the medical literature to see if there was any suggestion it could be of benefit to patients with myelopathy.
How did we go about this?
We performed something called a systematic review and this has recently been published in the journal of Clinical Rehabilitation. (1) This is a research technique which rigorously screens databases of medical literatures. Typically this is done in three stages: Firstly, a search strategy (string of relevant words) is put together. This is then applied to medical literature databases and the results of the search are manually screened, initially by their title and summaries. Any articles considered potentially relevant and then read in full to evaluate their relevance to the research question.
What did we find?
We found only one study commenting on the effects of physiotherapy after surgery for DCM. This is a small retrospective study of 21 patients with DCM that underwent surgery and then rehabilitation. However it was a poor quality study, and spontaneous recovery after surgery could not be distinguished from the effects of physiotherapy specifically. Although the study concluded that rehabilitation improved functional status, the small study size and its design make this conclusions very tentative.
Therefore, unfortunately, we identified that the effect of postoperative physiotherapy in DCM has been poorly studied and we could not make any recommendations about whether it should be routinely provided. This does not mean that physiotherapy is harmful or should not be provided after surgery for degenerative cervical myelopathy but simply more investigation is required.
Pleasingly there are now two registered randomised controlled trials, one in Taiwan and another in Canada, which will hopefully shed light on the effects of postoperative rehabilitation in DCM.
1. Badran et al. Is there a role for postoperative physiotherapy in degenerative cervical myelopathy? A systematic review. Clinical Rehabilitation. April 2018.
by Max Stewart
It appears that the story isn’t quite as simple as we might initially think. Could there be other factors, beyond gross compression of the cord, which determine whether or not someone develops myelopathy?
A group of researchers at Wenzhou Medical University in China, led by Wu Shiyang , thought that one such factor could be reduced spinal blood flow. They reasoned that the same degenerative changes that compress the spinal cord in older people could also compress the blood vessels that supply it, the so called ‘spinal arteries’ (Figure 1). If these arteries became compressed there would be less oxygen reaching the cord, leading to death of nerve cells and inflammation of the surrounding areas. This damage to the spinal cord could lead to the symptoms of myelopathy.
What did this study involve?
To test whether spinal artery compression is associated with myelopathy, the Chinese researchers decided to look at the blood flow in one of the biggest arteries supplying the spinal cord, the anterior spinal artery (Figure 2). They compared flow in this artery between healthy people and people with DCM. The researches also compared blood flow before and after CSM surgery, to see if there was any link between improvement in symptoms and restoration of blood flow to the cord.
To look at blood flow, the researchers used an advanced technique called ‘dual energy computed tomography’ (DECT). Normal CT scans are used widely in hospitals, and some groups have tried to use them image blood flow in DCM. However, these efforts have been unsuccessful . Shiyang’s group are the first to use the more advanced DECT instead, which is able to produce better pictures of blood movement within arteries. DECT is complicated, but here’s a (very) simplified explanation. First, Iodine is injected into one of the patient’s arteries. The patient is then placed in the CT scanner. Two sets of mages are produced; one using a high energy X-ray beam, one using a low energy beam. Body tissues look similar in both types of X-ray, but iodine looks very different. By combining the two sets of images, a computer is able to focus on body structures that contain iodine – in this case, the arteries. The computer can then see how much iodine is flowing through the arteries and use this to work out blood flow.
The study involved 50 patients with confirmed DCM and 10 health patients. Both groups underwent DECT scans. The DCM group had their level of disability measured using the JOA score. The DCM patients then had surgery – each underwent an anterior cervical discectomy and fusion. The DCM patients then had another DECT scan after surgery (to see if blood flow in the arteries had changed) and then had JOA scores calculated again one month and six months after surgery.
Researchers then looked at:
1. The difference in blood flow between pre-surgery DCM patients and healthy patients
2. The difference in blood flow between pre-surgery and post-surgery DCM patients
3. Any link between change in JOA score (disability) and change in blood flow after surgery
What did this study show?
There were three important results from this study:
1. Blood flow through the anterior spinal artery is significantly lower in pre-surgery DCM patients than healthy patients
2. Surgery leads to a significant increase in spinal artery blood flow in DCM patients
3. Patients who had bigger improvements in blood flow after surgery had greater recovery in JOA score (i.e. were less disabled) 6 months later
What might these results mean for the future?
This study suggests that reduced blood flow to the spinal cord could be associated with the symptoms of myelopathy and that improvement in blood flow could help predict to recovery from surgery. These links between spinal artery compression and myelopathy could be important because:
1. They could help us better understand the underlying processes which damage the spinal cord in DCM, which in turn would help us develop new treatments. These results could even help explain why spinal cord compression on imaging doesn't always cause DCM – perhaps compression of the spinal arteries is also required for symptoms to develop.
2. They could help us diagnose myelopathy earlier. Reduced spinal blood flow could now be considered a sign of DCM, which we can combine with our existing diagnostic makers (MRI scans, neck pain, disability etc). The earlier we diagnose myelopathy the sooner we can operate and the less severe lasting disability will be. Remember: time is spine.
3. They could help us assesses how successful surgery has been and predict how much recovery we can expect. A big improvement in blood flow suggests that recovery will be better. This clarity can help us plan your future care and helps you know what to expect.
4. They could help us compare treatments to see which is best. Surgeries that produce the bigger increases in blood flow may lead to better recovery than surgeries which produce smaller improvements in blood flow. Shiyang’s group has already planned studies to see if DECT can be used to compare outcomes of anterior vs posterior decompression operations.
What are the limitations of this study?
Obviously, use of DECT and study of blood flow in general is still at a very early stage. Most hospitals don’t have access to DECT yet, so it will be a while before we could think about using it in diagnosing DCM. We’d also need to confirm that there is a consistent difference between healthy and DCM patients that is big enough to detect. Furthermore, we don’t know what processes reduced blood flow is actually triggering to the spinal cord. Finally, it is likely that compression of arteries is only one of many changes and disease processes that drive DCM. Time will tell just how significant the contribution of reduced blood flow is to the disease.
1. Shiyang, W. et al. Is Cervical Anterior Spinal Artery compromised in Cervical spondylotic myelopathy patients? – dual energy Computed tomography analysis of Cervical Anterior Spinal Artery. World Neurosurg. (2018). doi:10.1016/j.wneu.2018.03.217
2. Zhang, Z. & Wang, H. CT angiography of anterior spinal artery in cervical spondylotic myelopathy. Eur. Spine J. 22, 2515–9 (2013).
My name is Dr Teena Fernandez. I am a GP in North Wales currently undertaking research as part of my Masters in Sports and Exercise Medicine at Nottingham University. During my studies my husband sustained a cervical spine injury resulting in a 2 level anterior cervical discectomy and fusion and we found little advice or evidence on returning to sport following such surgery.
Can you help researchers from the University of Nottingham?
We did not know if he could go dog walking, do martial arts or do manual labour for 2 hours a day? I subsequently undertook research which only identified expert opinion on returning to sport. I have now (with the help of a neurosurgery consultant) decided to find out how people return to sport following 2 level anterior cervical discectomy and fusion.
I plan to undertake a qualitative project interviewing approximately 8-16 participants to find out whether they have returned to at least 2 hours of exercise a day following the surgery. I would like to know whether they developed problems such as neck pain or pain or loss of function of the arms and legs with exercise.
Being a GP, I hope I can interpret the interviews and help people who require advice on getting fit after surgery.
Please have a look at my advert and get in touch if you would like to be involved.
Dr Teena Fernandez
MBBS MRCGP DFFP DRCOG BMEDSCI PGCE
Why does this matter? A word from the director
The role of exercise after surgery in CSM is largely unexplored. However there is much to suggest that it can enhance recovery; indeed this is well demonstrated in animal studies of spinal cord injury, underpins the basis for spinal cord injury rehabilitation centres and is starting to be evidence based in traumatic spinal cord injury. So at Myelopathy.org, we are pleased to support this research study. It should be noted, that this study is not just for CSM and looks in particular at higher performance athletes (exercising more than 2 hours per day), but no doubt this will have some relevance and we look forward to seeing the results. Ben Davies, Director Myelopathy.org
Worried about participating in research?
Myelopathy.org ensures all affiliated research meets UK Research Standards. A useful video has been prepared by Connected Health Cities and The Farr Institute to provide an overview of how health research is conducted and overseen in the UK, including how your data is looked after and used. If you have any further questions or concerns, please get in touch.
Researchers from the University of Nottingham are looking into this, and want to learn from your experiences!
Many people undergo 2 level Anterior Cervical Discectomy and Fusion Surgery, this includes patients with CSM. The operation requires the removal of 2 intervertebral discs and the fusion of the cervical vertebrae. Current advice is unclear about whether a person can take up sport following this surgery. Doctors are concerned about safety to the spinal cord if people return to sport following this surgery. This study will interview 16 people who regularly exercise following this surgery. It is hoped these experiences will allow patients to be advised more accurately in the future.
Can you help? Find out more about the study and its lead investigator
What is the significance for CSM?
The role of exercise after surgery in CSM is largely unexplored. However there is much to suggest that it can enhance recovery; indeed this is well demonstrated in animal studies of spinal cord injury, underpins the basis for spinal cord injury rehabilitation centres and is starting to be evidence based in traumatic spinal cord injury. However this has to be balanced against any necessary 'healing' time for the surgery itself, with many surgeons recommending months of very limited activity. So at Myelopathy.org, we are pleased to support this research study as it represents an important knowledge gap. It should be noted, that this study is not just for CSM (as ACDF can be performed for other reasons) and looks in particular at higher performance athletes (exercising more than 2 hours per day), but no doubt this will have relevance and we look forward to seeing the results. Ben Davies, Director Myelopathy.org
"The dogma that the central nervous system cannot regenerate is simply not true; we just haven’t figured out how to make it happen yet."
These neurons, and their connections to the spinal cord, do not regenerate. To regenerate specific neurons, we must understand how they are generated in the first place. In other words, we believe that the key to achieving therapeutic regeneration is a clear understanding of development.
How genes are regulated to control corticospinal motor neuron development is just beginning to be understood. One way genes are regulated is by small, non-coding RNAs (microRNAs). Our lab has recently discovered that microRNAs appear to be critical to corticospinal motor neuron development. The members of my lab are investigating the ability of microRNAs to control corticospinal motor neuron development in the embryo, in immature brain cells in the dish, and in stem cells.
Why is this exciting?
Regulation by microRNAs represents an entirely new way of understanding the generation of these important neurons. If we can understand how neurons naturally develop, we will be able to identify targets to stimulate their regeneration.
1) Tharin Lab, University of Stanford
2) S.Tharin et al A microfluidic device to investigate axon targeting by limited numbers of purified cortical projection neuron subtypes. Integr Biol (Camb) Nov 2012
3) Iyer et al. Cervical Spondylotic Myelopathy. Clin Spine Surg. Jun 2016
Dr. Satkunendrarajah, from the Fehling's Lab Canada, is using animal models to understand how the electrical connections of the spinal cord are disrupted in CSM
What are you working on at the moment?
There is now evidence to show CSM patients are more likely to suffer breathing related illnesses, such as pneumonia and atelectasis (partial or complete collapse of the lung). (3) (4) This may correlate with the severity and level of cord compression.
Why does this excite you?
1. SK Karadimas et al. Riluzole blocks perioperative ischemia-reperfusion injury and enhances post decompression outcomes in cervical spondylotic myelopathy. Sci Trans Med 02 Dec 2015: 316ra194
2. SK Karadimas et al. A novel experimental model of cervical spondylotic myelopathy (CSM) to facilitate translational research. Neurobiol Dis. 2013 Jun;54:43-583. Toyoda, H et al. Does chronic cervical myelopathy affect respiratory function? J Neurosurg Spine 1:175-178.
4. Gelaye, A et al. Difficult-to-wean: High index of suspicion. Am J Case Rep 2014 15:163-167.
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