A Tarlov Cyst is a cyst that can develop within the layers of the sheath that covers a nerve root. When one of these layers develop a weak spot it will begin to fill with CSF (cerebral spinal fluid) and balloon out forming the cyst.
Named after the neurologist
that first studied them.
TCs were first described by the neurologist Isadore Tarlov in 1938. Research since that time has been limited.
There is widespread disagreement among scientists regarding the possible causes, symptoms, and best treatments for these cysts.
On the Spinal Nerve Roots
There are many different types of cysts that can develop in different areas. TCs are found on the spinal nerves close to where they exit the spinal canal.
They most commonly occur in the sacral region as part of the sacral nerve roots, S1, S2, S3, and S4.
Tarlov Cysts develop within the
Epineurium or Nerve Sheath
Image thanks to Wikimedia Commons
No Clear Cause has ever been found
The cause of TCs has never been clearly defined. Some theories suggest that they are a congenital deformity while others think that they may be related to childhood trauma. Dr Tarlov postulated that these cysts may develop when minor trauma caused problems with the nerve root blood flow.
Unfortunately, none of these theories have been scientifically proven.
Most TCs are completely asymptomatic meaning that they do not cause any symptoms. They are often discovered as an incidental finding on an MRI that is done for other reasons.
Depending on which study you believe these cysts may cause symptoms in 15-30% of cases. Symptoms are most commonly caused by the expanding cyst placing pressure on surrounding bones or nerves.
Most Common on the Sacral Nerve Roots
The sacrum, where most TCs are found, is a solid piece of bone that is made up of five sacral vertebrae that are fused together. When the cyst expands and begins pushing against the bone it may cause the bone to erode or recede.
This may cause pain across your sacrum or pain radiating into your abdomen.
A cyst that is putting pressure on nerves or nerve roots may cause pain and other problems in the area that nerve serves. The sacral nerves innervate the genital and peri-rectal regions.
Compression or other irritation of these nerves may cause problems controlling your bowels or bladder, numbness around your rectum or genitals, or pain and muscle weakness in your lower extremities. Your exact symptoms will depend on which nerve is being irritated and the severity of the pressure or irritation.
Image thanks to Raynata, via Wikimedia Commons
Most TCs are small and they do not cause any symptoms. In these cases no treatment is necessary. When larger cysts do cause symptoms they are often related to the enlarging cyst putting pressure on surrounding bone or nerves.
Tarlov cysts also have nerve fibers within the cyst wall or within the cyst itself that may cause symptoms.
Always begin with the most
Treatment options for Tarlov cysts that are causing pain and/or other symptoms always begin with conservative therapies such as medications and then progress to more aggressive treatments like injections or surgery.
If you have a cyst that is causing pain across your sacrum, abdomen, or radiating into your genitals or buttocks your doctor may trial some different pain medications to try and make you more comfortable.
Anti-inflammatory drugs like diclofenac or meloxicam may help by relieving swelling and inflammation. These drugs may affect your stomach or kidneys and should only be used under the direction of a physician.
Narcotics and Anti-Seizure Medications
Narcotic pain medication can be helpful for nociceptive pain (pain that is coming from the pain receptors), but they are less helpful for neuropathic pain (pain that is coming from the nerves). These medications also have risks and will need to be prescribed by your doctor.
Anti-Seizure drugs like gabapentin or pregabalin can help relieve neuropathic pain, but they are not very good for relieving nociceptive pain. These too will need to be prescribed by your doctor.
Symptoms besides Pain
If you are having other symptoms besides pain such as difficulty controlling your bowels or bladder your doctor may refer you to a specialist for special testing to rule out other possible causes of your symptoms.
Injection Treatments for Tarlov Cysts
Steroid medicine injected into the area of the cyst may relieve your symptoms by reducing the pain and swelling. The medication will be slowly absorbed by your body over the following 6 weeks. How much relief you get and how long it will last is very variable.
Some people only see a short period of minor relief while other get more significant relief that may last for several months. You don't know if you don't try.
Image thanks to Austin Samaritans, via Wikimedia Commons
Some doctors will draw fluid out of the cyst to deflate it and then inject a fibrin glue to try and keep it from refilling with fluid. Fibrin is a naturally occuring substance that helps your blood to form blood clots.
Unfortunately, these treatments are not always successful and the cyst will quickly fill back up with fluid causing your symptoms to return.
If injection treatments are not helpful you may be referred to a neurosurgeon. He can go in and surgically
remove the cyst and repair the nerve sheath. You will need to discuss the risks of surgery including possible nerve damage before deciding to have surgery.
There are treatments for Tarlov Cysts that are causing problems but they are not always effective.
More aggressive treatments have increased risks. You need to discuss these risks with your doctor who knows your medical history and what other medical problems you are dealing with.
He can help you understand how they relate to you and your situation.