Q: One of my relatives has had lower-back pain, and they diagnosed her with a synovial cyst. They tried to put a needle in it to take out the fluid, and now they want to do surgery. What is this disease, and is surgery the right answer?

Q: One of my relatives has had lower-back pain, and they diagnosed her with a synovial cyst. They tried to put a needle in it to take out the fluid, and now they want to do surgery. What is this disease, and is surgery the right answer?


A: Lower-back pain is extremely common; 3 out of 4 people will have at least one severe episode of lower-back pain in their lifetimes. Over 90 percent of these are from muscular skeletal injury/strain (especially in younger people) and resolve with only conservative treatments such as:




Over-the-counter pain medication.

Ice after an acute flare up to help decrease local inflammation (use a washcloth to keep the ice from being directly on the skin, then leave it 20 minutes on and 20 minutes off frequently for the first two to three days).

After this initial period of ice treatments, heat (heating pad or hot water bottle are fine, be careful to avoid burns) can be tried or the ice treatments continued, whichever helps more.

Return to normal activity as quickly as tolerated.

And, most importantly, tincture of time (patience), as these episodes typically resolve over a month or so.

However, if the back pain becomes chronic or there are concerning symptoms (such as radiculopathy with leg weakness, loss of sensation and/or other focal neurologic signs along the course of the nerve), this may be an indication that something is mechanically pressing on a nerve as it leaves the spinal cord. MRI or CT myelogram help identify the anatomy of the cause, such as a herniated disc or even a synovial cyst.


The lower spine is actually several joints, where the spinal bones meet but movement is preserved. The spine is also important in the structural integrity of the skeleton and to protect the nerves of the spinal cord.


Each spinal joint has a “disc” of gelatinous material in the middle with a harder cartilage around the outside. This acts as shock absorbers between the spinal bones, allowing the backbone to move and put up with daily stress and strain. If a part of this disc gets squished and bulges out, it is called disc herniation. This becomes more common with age, likely due to repeated wear and tear on the discs as well as degenerative changes of the discs themselves. Disc herniation is a relatively common cause of radiculopathy; I have discussed this in a previous column.


A synovial cyst is a fluid filled sac that can develop in the joint. Overall, these are uncommon, being a contributing cause in less than one of 200 people with radiculopathy. They usually occur in the most mobile part of the lower spine, between the fourth and fifth lumbar bones. Although the specifics of why they develop are not completely understood, wear and tear and degeneration of the spine may be a contributing factor. These typically do not develop until people are in their 50s and 60s.


There are documented cases of synovial cysts resolving without any intervention; however, the severity of symptoms and chronicity of the problem often leads to the decision to intervene in a more aggressive way than the conservative methods discussed above.


Since a cyst is a fluid filled sac, it may seem logical to put a needle into it to drain the fluid. As there is often inflammation from the irritation of the cyst pushing on nearby structures, injection of steroid medication may also be attempted. Most of the studies I was able to find on this condition are small, and many have some methodological limitations (not surprising for an uncommon condition where it is difficult to study large numbers of patients), however several of them showed limited efficacy of these treatment options. Therefore, surgical intervention is often recommended.


There are many possible surgical approaches, and the specific type of surgery recommended depends on the details of the patient’s condition. One important feature is the stability of the joint; unstable joints may benefit from fusion (where the movement of the joint is intentionally restricted).


Patients diagnosed with a lumbar synovial cyst should consult with an experienced surgeon, reviewing the potential benefits and risks of each treatment option.


Jeff Hersh, Ph.D., M.D., F.A.A.P., F.A.C.P., F.A.A.E.P., can be reached at DrHersh@juno.com.