This is a surgical emergency caused by severe compression of the cauda equina (the nerve roots below the end of the spinal cord), affecting the nerve signals to the legs, and those that control bowel and bladder function. Patients need urgent surgical decompression of the affected area, but even with this treatment, some patients will not fully recover complete function.
The spinal cord typically ends at the L1/2 level at the region known as the conus terminalis, and then becomes the cauda equina. These are the nerve roots that each exit the spine through an exit foramen at the appropriate level, and then give nerve supply to the group of muscles for that level. The spinal canal is the area surrounding the cauda equina to protect these vital structures, but also allow us to stand and mobilise by providing support to the muscles. It is comprised of individual vertebrae, as well as the discs and ligaments that support the bones and allow movement between the bones.
Cauda equina can be caused by anything that causes compression of the spinal canal. This includes herniated discs (the most common), tumour, infection, fracture, or degenerative disease of the spine. It is relatively easy to diagnose when presenting as an acute issue as patients typically will present with severe pain, difficulty using their legs (to a varying degree) and possibly bowel and/or bladder dysfunction. When it presents slowly the symptoms can be vague and difficult to diagnose.
Patients should present to their local doctor or emergency department if they have the following symptoms:
Your doctor will perform an examination looking to confirm the extent of the neurological issue. This includes testing strength of the legs, assessing sensation and reflexes. They also need to test the strength of the anal sphincter muscles and sensation around this area. The other test typically performed will be a bladder ultrasound scan to determine the amount of urine within the bladder.
The gold standard test in this setting is an MRI scan, as this will allow for an accurate diagnosis of the region affected, as well as the structure that is causing the compression. MRI is generally required before having surgical decompression as this allows for surgical planning to ensure that an adequate procedure is performed.
In some patients where MRI scan is not possible, CT scan can be performed.
Cauda equina syndrome requires urgent decompression to remove the material that is causing compression of the nerves. This can be laminectomy with discectomy, or laminectomy and fusion.
Even with prompt surgical decompression, normal function does not always completely return. Patients may be left with bowel and bladder dysfunction, as well as sexual dysfunction. There may also be issues with numbness and/or weakness of the legs. If this is the case, you will given support from staff within the hospital, and then once you return to home to allow you to get the best possible return to function.