Degenerative Cervical Myelopathy (DCM) is a common spinal cord disorder. What do these words mean?
- Degenerative = in our case this refers to the gradual worsening of the integrity of the spinal column (bones, ligaments and intervertebral discs)
- Cervical = concerning the neck
- Myelopathy = injury to the spinal cord
DCM results from degenerative changes caused by wear and tear in the spinal column. These structural changes reduce the space for the spinal cord, which is housed inside the spinal column. The degenerative changes cause mechanical stress and compression of the spinal cord, and this can trigger a ‘slow-motion spinal cord injury’.
It is important to recognise that these degenerative changes of the spinal column are very common, and most often a normal finding: such changes can be seen on neck scans of 1 in 5 healthy adults, and become even more common as we get older. However, in a subset (~10%) of these people, over time this can affect the spinal cord and lead to DCM.
The processes that lead to DCM can, therefore, be thought of in three phases:
- Spondylosis or degeneration of the spinal column occurs. These ‘wear and tear’ arthritic changes cause mechanical stress on the spinal cord, mostly by compressing it.
- In a subset of individuals, the mechanical stress will trigger the myelopathy or damage of the spinal cord.
- The disease evolves as further damage to the spinal cord occurs. However, the response of the spinal cord to compression differs from person to person, meaning that each individual will experience this differently.
Because of problems with diagnosis, the number of people who suffer from DCM is unclear. It is estimated to affect up to 5% of people over the age 40 (~2% of adults). This is expected to rise as populations age .
The name ‘Degenerative Cervical Myelopathy’ has recently been introduced as an umbrella term for several degenerative changes of the spine that can result in myelopathy in the neck. However, there are as yet no specific and recognised disease codes (e.g. International Classification of Disease) or literature database (e.g. Medical Subject Heading) codes, making it difficult for researchers to find or interpret clinical studies. We are working with our global community to produce a clear definition for DCM, which will enable the creation of disease codes. Not only will this streamline research into the condition, but also it will allow scientists to speak a common language when referring to the disease.