What are Tarlov Cysts?
Tarlov cysts or perineural sacral cysts are described as fluid-filled sacs that most often effect nerve roots at the lower end of the spine (sacrum). Tarlov cysts were first identified in 1938, yet there is still very limited scientific knowledge available.
One explanation for the limited research is the problem of understanding the importance of Tarlov cysts in problems of back pain.
New research looking to confirm or deny the importance of Tarlov cysts in problems of sciatica, suggests that “These cysts are rarely sources of complications due to distorting, compressing, or stretching of adjacent sacral nerve roots. These are symptomatic in 12% of cases and responsible of 0.2% of the lumbosacral radicular pain.”1
More research from 2016 centers around when Tarlov Cysts do cause problems, because of the seeming rarity of the cysts being the root cause.
These lesions are generally reported as incidental findings on CT or MRI studies. This condition affects women far more frequently than it affects men. These cysts can occur anywhere in the spine, but the most common areas affected are the sacral area the S-2 and S-3 nerve roots.
On average most Tarlov cysts are small, but some can be as large as 6 cm (about 2.4 inches). There is some confusion over the precise definition of Tarlov cysts and how they are different from other spinal cysts. The distinctive feature of the Tarlov perineurial cyst is the presence of spinal nerve root fibers within the cyst wall or cyst cavity itself.
The exact cause of Tarlov cyst is unknown, but there are theories as to what may cause an asymptomatic Tarlov cyst to produce symptoms. In several documented cases, accidents or falls involving the tailbone area of the spine caused previously undiagnosed Tarlov cysts to flare up. Symptoms vary greatly by patient, and may flare up and then subside.
Any of the following signs and symptoms may be present in patients that have symptomatic Tarlov cysts:
- Pain in the area of the nerves affected by the cysts, especially the buttock
- Weakness of muscles
- Difficulty sitting for prolonged periods of time
- Loss of sensation on the skin
- Loss of reflexes
- Changes in bowel function, such as constipation
- Changes in bladder function, including increased frequency or incontinence
- Changes in sexual function
Non-surgical therapies include lumbar drainage of the cerebrospinal fluid, CT scanning-guided cyst aspiration, and a newer technique involving removing the CSF from inside the cyst and then filling the space with a fibrin glue injection. Unfortunately, none of these procedures prevent symptomatic cyst recurrence. Injections of corticosteroids usually help. Other neurosurgical techniques for symptomatic Tarlov cysts include simple decompressive laminectomy, cyst and/or nerve root excision, and microsurgical cyst fenestration and imbrication. The key to deciding about treatment of these cysts is to be certain the cyst is the cause of the symptoms. Before deciding on intervention the symptoms should be serious enough that their treatment is indicated.
Prolotherapy for Treating Tarlov Cysts
There are many times when Prolotherapy can be used when someone has a Tarlov cyst. It is on a case by case basis and dependent on physical exam, and other tests, such as ultrasound scans and EMG/NVC. Generally, surgery is done to remove the cyst if the EMG/NCV test confirms that a nerve is getting injured and this is the nerve where the cyst is located. If exams indicate that the pain is associated ligament laxity and joint instability (such as SI joint instability), Prolotherapy could be the treatment of choice. In such a situation, there is a good chance that Prolotherapy can give a lot of symptom relief and restore function.
1 Mahmoudi SF, Layeb M, Layouni S, Jemni S, Gaddour M, Jeddou KB, Khachnaoui F. The Tarlov cyst: A cause of sciatica. Ann Phys Rehabil Med. 2016 Sep;59S:e95. doi: 10.1016/j.rehab.2016.07.215.