Understanding, Diagnosing and Treating Cauda Equina Syndrome
Patients who have cauda equina syndrome usually have lower back pain, sciatica on one side or both, leg weakness, change in sensation in the "saddle" area, and possible loss of bowel or bladder. This is caused by pressure on the nerves.
The spine is made up of vertebrae (bones) that align one on top of the others to form the back. These vertebrae protect the nerves and other portions of the spine. The meninges, the membranes that surround the spine and brain, and the spinal fluid are also part of the protection of the spine. The outermost meninge is called the dura mater. Finally, the nerves that go down along the spine and branch off are called nerve roots. Near the bottom of the spine is an area that has a bundle of nerve roots and this is called the cauda equina.
As with any part of the spine, if a certain part is compressed, there can be pain, changes in sensation, weakness, and slowed reflexes. When this happens in the lower back and is severe, this is called cauda equina syndrome. Because of the severity of the problem, this is considered to be an emergency.
There are several issues that can cause cauda equina, including trauma and injury, tumors, build up of fluid that causes pressure, are a few.
To diagnose cauda equina syndrome, doctors need to do a thorough physical exam including x-rays to rule out other problems and to find at what level the nerves are being pressed. Sometimes, it is possible to confuse a bulging or herniated disc for cauda equina, so this is an important distinction to make.
Pain, for people with cauda equina syndrome can come on very suddenly (acutely) or slowly (chronically). Regardless of how the pain comes on, it is usually quite severe. "Saddle anesthesia," a loss of sensation around the genitals, is a very suspicious sign for this syndrome.
When reviewing the patient history to see if cauda equina syndrome is a possibility, beside the traumatic injuries that are possible, other things to watch out for are activities like weight lifting or chiropractic manipulation. Losing control of the bladder is another symptom, but occasionally, this is the reverse and urine is retained. Loss of bowel function is possible but not as telling for diagnosis as bladder dysfunction.
The different symptoms can also help tell doctors how the chances of recovery are for individual patients. For example, if a patient has problems with their bladder, they have a better prognosis if they have retention rather than loss of control. If a man experiences erectile dysfunction, this is usually not a good sign for recovery.
When testing, after x-rays, often the next step is myelography, which is using x-ray and dye to evaluate the vertebrae. This is being replaced now more with magnetic resonance imaging and computed tomography scanning, with MRI being the most reliable, doctors feel. However, MRIs can't be done on all patients. Patients with metal hardware, such as pacemakers, clips to repair aneurysms, or metal fragments near vital organs or near the eyes can't have an MRI because of the magnets used to make the images.
Some doctors may choose to do bladder studies, checking to see how well the bladder is working, but this isn't considered to be a definite sign of cauda equina syndrome.
Once cauda equina syndrome has been diagnosed, it must be classified as incomplete or complete with retention. Incomplete cauda equina syndrome is diagnosed with the patients still have some function of their bowels and bladder, although they do have back pain and saddle anesthesia. Complete with retention is, as the name infers, with retention of urine.
Seeing as this is considered to be a medical emergency, surgery must be done as soon as possible but researchers don't agree on how quickly it needs to be done. Delays in surgery could be caused by a delay in diagnosis, delay in testing, and/or delay for the surgeon or the operating room.
The authors of this article conclude that the surgery does have to be considered to be an emergency in order to decompress the spine, or remove the stress on the nerves. Most surgeons feel that this should be done within 24 to 48 hours of onset and diagnosis.
Alex Gitelman, MD, et al. Cauda Equina Syndrome: A Comprehensive Review. In The American Journal of Orthopedics. December 2008. Vol. 37. no. 11. Pp. 556-562.