By B Hilton
Finger flexion, Hoffmann reflex, and Plantar Reflex in DCM
Degenerative cervical myelopathy (DCM) produces a range of symptoms (changes that patients report) and signs (changes that doctors detect through examining a patient). There are several reflexes that occur when the cervical spinal cord is compressed, as it is in DCM. These are: finger flexion, Hoffmann reflex, Plantar reflex (Babinski sign), generalised hyperreflexia, and clonus. Let’s focus on the first three.
Finger flexion - when a doctor taps the base of your fingers with a tendon hammer and your hand moves as if beginning to bring your fingers into a fist
Hoffmann reflex - when the end of your middle finger is flicked downwards, your thumb and first finger flex, as if going to touch each other
Plantar reflex (also known as the Babbinski Reflex) - when a doctor scratches the outside edge of the bottom of your foot and your toes point upwards towards your head
However, these reflexes are not always present in DCM and may be caused by other diseases too. A team of researchers in India investigated how common the reflexes were in DCM and compared this to how common they were in people without DCM.
The team tested the three above reflexes in 32 people with symptoms of DCM and 304 people without DCM. Findings were cross-checked and all participants in the study received an MRI scan of their neck. 24/32 symptomatic patients also had cervical spinal cord compression on their scan. Here’s what they found
Clearly these reflexes are much more common in patients with spinal cord compression and only rarely occur in totally asymptotic patients without spinal cord compression. The team found that when all three reflexes were tested together, if one reflex was positive they could be 92% sure that the patient had DCM. If none of the reflexes were present, they could be 78% sure the patient didn’t have DCM.
What does this mean?
Well we know that detecting early DCM is difficult. What this study shoes is that perhaps the combination of these three tests could be used to assess patients who had been experiencing symptoms consistent with DCM. If even one reflex were positive, they could be >90% sure the patient’s spinal cord could be compressed. If all 3 reflexes were negative, they could be >75% sure that the person’s spinal could wouldn't be compressed. In addition to the patients history, symptoms, and other examination findings, testing these reflexes could offer important insight into who should receive an MRI and potentially see a surgeon scan more urgently and who can likely afford to wait a short while longer.
Of course, it is clear that this reflexes are not perfect. And there are a group of patients with DCM, in whom these reflexes are normal.
1) Tejus MN, Singh V, Ramesh A, Kumar VR, Maurya VP, Madhugiri VS. An evaluation of the finger flexion, Hoffman's and plantar reflexes as markers of cervical spinal cord compression - A comparative clinical study. Clin Neurol Neurosurg. 2015 Jul;134:12-6
Having a raised Body Mass Index (BMI) is known to lead to poorer patient outcomes in surgery for lower back problems. However, what impact does a raised BMI have on patients who undergo surgery on their neck for Degenerative Cervical Myelopathy (DCM)? A team of researches in Canada decided to investigate
What did they do?
The team looked at data collected from patients operated on for DCM in 26 centres located in America and Canada. 757 patients were included in the study and were split into groups based on their BMI: underweight, normal weight, overweight, and obese. The researchers then looked at how well the groups of patients faired after surgery on their neck for DCM.
Patient outcomes were assessed by looking at three outcome domains: function (using a scale called the mJOA), symptoms (using a scale called the NDI or neck disability index), and quality of life (using a scale called the SF-36).
They went on to control their results for many other factors such as the patient’s age, level and severity of DCM, surgical technique, which are known to affect how patients respond to surgery By doing this, any differences between the groups of patients post-surgery could be attributed solely to differences in their BMI (and not bias by other factors).
So what did they find?
The researchers found that the greater a patient’s BMI, the higher their Neck Disability Index i.e. symptoms would be after surgery. NDI is a measure of difficulties patients have in day-to-day life such as with personal care and reading that are caused by pain in their neck. The team also found strong trends but no significant relationship between patients’ BMI and their quality of life after surgery (MCS/PCS).
So, what does this all mean? Well, the researchers suggest that although patients with a raised BMI have good functional outcomes from surgery, this appear to be less likely to translate into practical improvements in their day to day activities.
However, the trouble with examining NDI in this setting is that it relates to disability caused by neck pain, a feature which DCM surgery does not specifically aim to improve. By the functional measures that surgery aims to improve or at least stabilise (mJOA), patients with BMI were no worse off post-op than those with normal weight.
What can we conclude?
We have recently described a study showing fat infiltration in neck muscles is associated with greater neck pain in myelopathy. Is this more evidence that obesity can worsen symptoms of DCM?
What remains to be seen, is whether efforts to counter obesity can help improve symptoms in DCM. However there is clearly a growing number of studies pointing towards a relationship and that requires further investigation.
Of course, weight loss in DCM will be easier said then done, given the functional impairments, but if it can make a positive impact, surely it is worth pursuing?
1.Jefferson et al. Impact of Elevated Body Mass Index and Obesity on Long-term Surgical Outcomes for Patients With Degenerative Cervical Myelopathy: Analysis of a Combined Prospective Dataset Feb 2017 Spine
By J Tempest Mitchell
When considering whether to undergo surgery for treatment of CSM, one of the biggest questions that people want answered is what the risks are, and how likely they are to occur. Well, they’re in luck- a team from China have just completed a large-scale study, looking at previous research on the topic, to try and find out exactly that (1)!
Overall, the researchers looked at over 100 previous studies, and more than 8500 patients who underwent surgery to treat CSM, and found that just over 20% experienced some degree of complications from the surgery: in other words, twenty out of every hundred patients had some form of issues afterwards. Whilst this percentage may initially seem quite high, it is important to remember that CSM surgery can be life-changing, and that many of these side effects may be only temporary or minor compared to the damage that the disease itself can cause.
So what sort of complications did patients experience?
The most common of the complications examined in the study was difficulty or pain on swallowing, which nearly 17% of the patients studied reported on the first day after surgery (although the data doesn’t tell us how long this effect lasted beyond that first day). The next most common complication was axial (neck) pain, which was reported by 15.6% of patients.
Other problems seen after surgery were:
· Damage to the nerve C5, which supplies part of the upper arm (5.3%)
· Hoarseness (4.0%)
· Graft subsidence, an issue where the graft sinks into the bones of the spine, causing distortion (3.7%)
· Dislodgement of the graft (3.4%)
· Infection (2.8%)
· Failure of the bones in the spine to fuse (2.6%).
Two rarer, but potentially more serious complications seen were infection of the CSF (the fluid surrounding the spinal cord) in 1.9% of patients and epidural haematoma (bleeding between the outer lining of the spinal cord and brain, and the skull) in 1.1%.
These complication rates varied slightly, depending on the subtype of myelopathy from which patients were suffering, and also the exact operation type. In particular, patients with myelopathy caused by OPLL (a condition in where a flexible structure known as the posterior longitudinal ligament thickens and become less elastic) had a higher risk of damage to the C5 nerve and CSF infection after surgery.
This information is useful to allow patients to make an informed decision. It should be remembered that despite these possible problems, overall surgery for CSM has been shown effective to stop disease progression.
The team looked at past medical records and matched together 21 pairs of patients. In each pair, the patients’ age, gender, anaesthetic classification, and operative parameters were the same. The only difference: one of each pair had CSM while the other had CSM and PD. All patients underwent decompressive spinal surgery for their CSM. The researchers subsequently followed-up the patients to see how they fared after surgery. They found that patients with CSM and PD showed similar improvement to CSM patients for most areas; upper limb function, sensory disturbance, and bladder function. However, not with lower limb function. Additionally, overall, patients with PD were less likely to achieve what is referred to as a minimum clinically important difference, i.e. an improvement that is deemed to be worth while.
So, what does this all mean? Well, despite the study’s small sample size, this work suggests that patients with both CSM and PD can benefit from standard CSM surgery, although not always and not to the same extent as those with just CSM. Ultimately, this study calls for further research looking at the interplay between PD and CSM. As in order to best treat patients, CSM doctors must be able to discern the major culprit for the patients’ symptoms and advise patients accurately whether they would benefit from surgery (which is not without risk).
1) Xiao et al. Clinical Outcomes Following Surgical Management of Coexisting Parkinson Disease and Cervical Spondylotic Myelopathy. Neurosurgery Feb 2017
dsMRI is a modified form of the normal imaging technique, first introduced in the 1980s. This form of dynamic MRI imaging can be carried out in the same, standard, MRI machines we use now. Images are still taken with the patient lying down in the scanner (‘supine’), but rather than just take one series of images, the spine is imaged through a range of different neck positions (‘dynamic’), so its effect on the spinal cord can be seen. The major drawer back for patients is the imaging takes even longer (the researchers in this article estimate this would be an additional 15 minutes) and holding the different neck positions may not be possible for patients, as it could exacerbate their symptoms.
Do you suffer from CSM or know someone who does? Then share your experiences to help researchers understand the disease
In this article, the researchers found thirteen previous studies comparing dsMRI to traditional MRI techniques in the diagnosis of CSM. They found that on average, dsMRI was able to identify compression that was either missed or underestimated by traditional techniques in around 20% of patients. This suggests that dsMRI may be able to measure spinal cord compression with a higher degree of sensitivity.
It should be noted that the types of studies conducted so far are at risk of bias which means that the conclusions of this study can only be hesitant. Nevertheless, these findings are interesting as they have identified clear examples of where a standard MRI may not identify any compression, yet dsMRI does. And of course, many doctors rely on ‘MRI compression’ to make their diagnosis.
Additionally given ‘basic’ MRI imaging has been shown to poorly predict the severity of CSM and therefore response to surgery, could dsMRI change this and better inform patients?
One thing is certain, more investigation is required!
(1) Nanfung Xu et al. Does Dynamic Supine Magnetic Resonance Imaging Improve the Diagnostic Accuracy of Cervical Spondylotic Myelopathy? A Review of the Current Evidence, World Neurosurgery http://dx.doi.org/10.1016/j.wneu.2017.01.047.
By looking at MRI scans, the team were able to identify a larger amount of fatty tissue in two neck muscles, directly above and below the point of spinal cord compression. A larger build-up of fat cells was found to be linked to heightened symptoms of CSM, such as taking longer to walk 30m, and more difficulty with movement. They also found that patients with unevenness in one of their other neck muscles reported greater neck pain, and associated problems.
The increase of fat cells in muscle can be linked to a number of causes, but is most often seen as a normal part of the ageing process. Previous research has already found that we can reduce this age-related build-up of fat using physical activity and regular exercise (2), so the Canadian team speculate that a scheme of targeted neck exercises might help to improve the results of surgery in the treatment of CSM.
It’s important to remember however, that this research is still in its early days, and that so far, and a number of questions remain unanswered:
- Can neck exercises reverse fat infiltration?
- if so, what type of exercises are appropriate?
- Does this improve patient symptoms?
- Is it a consequence of CSM, or related to its origins?
It should be remembered that neck exercises will not remove the compression behind CSM and that at present, this can only be treated with surgery. Additionally some suggest extensive neck therapy before surgical treatment can make symptoms worse. (3) More work will need to be done to see whether the possible benefits of exercise are actually seen in patients, and if so, which types of exercises are most useful. However, if the suggestions made in this paper are found to be accurate, then this could be a simple way for patients to change the way that they prepare for surgery, in order to improve results.
(1) Fortin M, Dobrescu O, Courtemanche M, Sparrey CJ, Santaguida C, Fehlings MG,Weber MH. Association Between Paraspinal Muscle Morphology, Clinical Symptoms and Functional Status in Patients With Degenerative Cervical Myelopathy. Spine (PhilaPa 1976). 2016 May 23
(2) Hamrick, Mark W., Meghan E. McGee-Lawrence, and Danielle M. Frechette. “Fatty Infiltration of Skeletal Muscle: Mechanisms and Comparisons with Bone Marrow Adiposity.” Frontiers in Endocrinology 7 (2016): 69. PMC. Web. 15 Feb. 2017
(3) Rhee JM, Shamji MF, Erwin MW, Bransford RJ, Yoon T, Smith JS, Kim HJ, Ely CG, Dettori JR, Patel AA, Kalsi-Ryan S. Nonoperative management of cervical myelopathy: a systematic review. Spine
It has been well shown in many studies that Cervical Spondylotic Myelopathy (CSM) is a chronic and debilitating condition that reduces quality of life (1). However, until recently no one has studied how this compares to other common chronic conditions.
The study also found that the mental impairment caused by CSM was worse than for any of the other conditions, surpassed only by back pain and sciatica.
This was a well conducted, large, multi-centre study which successfully demonstrated that CSM carries a greater physical and mental disease burden than many other conditions, including cancer, diabetes and chronic lung disease. With a growing elderly population causing the prevalence of CSM to rise (3), the average age of a CSM patient is 57 (2), this study has made the important point that the condition is affecting an increasing number of people and to a greater extent than many better known diseases.
With this in mind, it is only fair to say that CSM deserves to receive a far larger share of medical attention than it does at present.
1. Al-Tamimi YZ, Guilfoyle M, Seeley H, Laing RJ. Measurement of long-term outcome in patients with cervical spondylotic myelopathy treated surgically. Eur Spine J . 2013 Nov;22(11):2552–7.
2. Oh T, Lafage R, Lafage V, Protopsaltis T, Challier V, Shaffrey C, et al. Comparing Quality of Life in Cervical Spondylotic Myelopathy with Other Chronic Debilitating Diseases Using the SF-36 Survey. World Neurosurg. 2017 Jan 5;
3. Wang MC, Kreuter W, Wolfla CE, Maiman DJ, Deyo RA. Trends and variations in cervical spine surgery in the United States: Medicare beneficiaries, 1992 to 2005. Spine. 2009 Apr 20;34(9):955-961-963.
We are often asked whether you should wear a neck collar after surgery for CSM. Some centres advise it and some do not.
This is a well conducted study, which shows very clearly that the collar offers no benefit on symptoms or recovery after surgery. It reiterates the same message discussion during the Myelopathy.org Patient Information Day.
So if there is no difference, should I wear a collar or not? This will need to be discussed with your surgeon. Whilst there is no benefit in terms of symptoms or recovery, some types of operation for CSM may require a period of stabilisation with a collar. It should be remembered that this study was done in patients undergoing cervical laminoplasty without instrumentation (metal fixation).
1. T.Hida et al. Collar Fixation is not Mandatory after Cervical Laminoplasty: A Randomized Controlled Trial Spine Nov 2016
2. Mark Kotter at the Myelopathy.org Patient Information Day
"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
This group followed up 135 patients with CSM, of which some patients underwent surgery and some did not. They found that the blood pressure of patients undergoing surgery improved (lowered) after surgery, whereas those who did not, remained the same.
You of course might say, well 'stress and pain' are a result of CSM, surely if they improve after surgery, my blood pressure will go down? Well the group measured pain, and found that the improvement of blood pressure did not relate to pain, but instead severity of CSM...
This puts the cat amongst the pigeons. Why should CSM cause high blood pressure?
That remains an unanswered question. This study did not measure stress, additionally some limitations in the study, particularly the number of patients, may have hidden a relationship with pain.
However there is some theory to the idea that CSM could affect your blood pressure. Control of blood pressure is naturally dependent on many things. Partly it relies on some very small nerve fibres called your 'Sympathetic Nervous System'. Although this nervous system is separate to your spinal cord, there is some communication which could be potentially disrupted in CSM. If we look at patients who have a traumatic spinal cord injury, their blood pressure is often unstable as a result. So there could be something more to this than simply pain or stress! We will have to watch this space! But be prepared to reduce your blood pressure medication after surgery if that is applicable.
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