Epidural Haematoma "Epee-jur-al"
The spinal cord lies within a sac called the 'dura' or 'dural sheath' or 'meninges'. Epi ['outside'] dural ['the casing around the spinal cord'] haematoma ['blood clot'] is a description for a blood clot forming around this sheath. This can happen for a variety of reasons, however because these structures lie within a bony canal, if a blood clot forms here it has now where to expand to and will therefore compress the spinal cord causing neurological symptoms.
Why is this relevant to CSM?
An epidural haematoma is a potential complication of surgery for CSM. It affects about 1% of operations.
During an operation a degree of bleeding is to be expected but the surgeon will endeavor to ensure that this is controlled and stopped. Occasionally a collection of blood can pool within the spinal canal causing spinal cord compression and myelopathy. If this were to occur, it would generally do so within the first 24hrs. A common story for this problem would be to awake after the operation with or develop within the first few days a worse function in arms and/or legs. If you are concerned about this, you should talk to your surgeon.
If this is to arise, a further urgent operation will be required to remove it. Generally a repeat scan is used to make the diagnosis.
Not to be confused with natural healing:
Following an operation, as the body starts to heal, the tissues involved in the operation swell. This increase in their size can also cause some gentle compression on nerves and it is common in the first few days after surgery for arm and leg function get a little worse before it gets better. This is entirely normal.