What is Tarlov Cyst?
Tarlov cysts are sacs filled with fluid that form between layers of the nerves in your spine. These cysts usually form near the joints where nerve roots and the spinal cord meet. Although they can happen anywhere in your spine, they mostly occur around the nerves of the lower back, especially the S2 nerve, which is primarily responsible for sensation and movement in the thighs and feet. Typically, these cysts are filled with cerebrospinal fluid, which is a clear, watery fluid that protects the brain and spine. However, if a cyst has a complication like rupturing or bleeding, it may contain blood.
Most often, these cysts do not cause any symptoms. However, if they do, these might include chronic back pain in the lower back or tailbone area. In some cases, there may be nerve-related symptoms like leg weakness, changes in bowel and bladder control, and sexual problems. These symptoms can be particularly severe if the cyst ruptures or bleeds.
The condition, first defined by American neurosurgeon Dr. Isadore Tarlov during autopsy examinations in 1938, bears his name.
What Causes Tarlov Cyst?
The exact reason why Tarlov cysts develop is still not known. However, the cysts usually don’t shrink by themselves and may actually grow because of spinal fluid flowing into the cyst. This happens through a sort of one-way valve system.
The term ‘arachnoid mater’ refers to a membrane that covers the brain. Around the entryway to the cyst, this membrane becomes scarred in a circular pattern, forming a valve. Some surgical treatments aim to target this area to restore the normal flow of spinal fluid and help the cyst reduce in size.
It has been observed that people with disorders such as Marfan syndrome and Ehlers-Danlos syndrome, which affect the body’s connective tissue, are more likely to have Tarlov cysts.
Risk Factors and Frequency for Tarlov Cyst
Tarlov cysts are quite rare. According to the most recent studies, about 4.27% of people worldwide and 3.82% of people in the United States have them. These cysts tend to be more common in women, with 7.01% of women and 4.05% of men having them. Moreover, about 15.59% of these cysts cause symptoms.
Signs and Symptoms of Tarlov Cyst
People complaining of chronic or recurring back pain often have issues with Tarlov cysts. Pain can spread to different parts of the body, leading to reduced feeling or weakness. Tarlov cysts can also cause discomfort in the genital or anal area, bladder and bowel issues, and sexual problems. A study indicated that these symptoms are likely to get worse with physical activity, while trying to bear down or defecate (Valsalva maneuver), or while sitting. These issues may become so bothersome that they interfere with work and social life. Other factors to consider when diagnosing this condition include whether the person has recently suffered trauma or if there are signs and symptoms of infection or cancer.
- Chronic or recurring back pain, sometimes spreading to other areas
- Discomfort in genital or anal area
- Bladder and bowel issues
- Sexual problems
- Pain worsens with physical activity, Valsalva maneuver, or sitting
- Possibility of interference with work and social life
- Recent trauma, infection, or symptoms of cancer
During a physical examination for Tarlov cysts, a detailed neurological checkup is conducted particularly for the areas showing symptoms. The skin areas and muscle groups of the lower limbs and genital or anal region are examined, along with reflexes in the lower limbs. Some signs such as urinary retention and decreased anal sphincter tone can especially point towards Tarlov cysts, because these lower motor neuron lesions can cause low reflexes, loss of feeling, and muscle weakness.
Testing for Tarlov Cyst
Depending on where you receive your healthcare, the steps for evaluating your situation may vary. For instance, in a general practice or emergency department, doctors often focus on the possibility of a condition called cauda equina syndrome, which can be caused by a larger-than-normal Tarlov cyst. Tarlov cysts are fluid-filled sacs that most often occur at the base of the spine. If there are signs of cauda equina syndrome–a rare but serious condition where nerves at the lower end of the spinal cord are squeezed–you’ll likely need to be referred to a spinal specialist.
Cauda equina syndrome can present in different ways, so medical professionals often concentrate on ruling out this diagnosis. The best way to do this is through a magnetic resonance imaging (MRI) scan of your lower spine (the lumbosacral spine). If you have certain health conditions that make getting an MRI unsafe, a procedure called CT myelography can be used, but it’s slightly more invasive.
MRIs are usually the preferred method for looking at Tarlov cysts. These cysts can be seen as thin-walled structures that are closely tied to the nerves in the spine. They are outside the spinal cord, but the nerve root is inside their walls. On the MRI, the cyst appears as a faint signal on the T1 image and a bright signal (like cerebral spinal fluid, or CSF) on the T2 image. The shape of the cyst can range from simple to complex, with different compartments and partitions. These cysts can also cause the openings in the tailbone area of the spine to widen.
Treatment Options for Tarlov Cyst
Treatments for Tarlov cysts, a type of spinal cyst, fall under three general categories: conservative treatments which take a less invasive approach, medical treatments that typically involve prescription medications, and invasive therapies, which include surgical techniques that can be either percutaneous (involving needle-puncture of the skin) or open surgeries.
If you have a Tarlov cyst but don’t experience any symptoms, doctors usually recommend conservative treatment. This means your doctor will monitor the cyst rather than treat it.
Medical treatments primarily deal with managing pain. These may include over-the-counter pain relievers, such as paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), and stronger pain killers (opiates). Other medications like antidepressants (e.g., amitriptyline) and anticonvulsants (e.g., pregabalin and gabapentin) may also be used to help manage the pain.
One specific treatment, caudal epidural steroid injections, has shown positive results for patients experiencing bladder pain and who are found to have incidental Tarlov cysts. However, this treatment is not commonly used.
With percutaneous therapies, the doctor can either drain the cyst or use a two-needle technique to drain and then inject the cyst with a substance called fibrin glue, all to prevent the cyst from refilling. One needle goes into the cyst while the other on the outside allows for the fluid to be drained and the air to be let in. This process can be monitored by CT scans. If the cyst quickly refills, physicians plug it with fibrin glue.
Open surgical techniques typically involve removing the cyst or creating an opening in it for drainage. After this, the covering of the spinal cord (dura) is repaired, and often, a special patch and/or fibrin glue are applied to prevent the spinal fluid leak. Some newer methods include blocking off the opening to the cyst and using a muscle graft, or shaping the cyst after creating the opening, both to prevent the cyst from refilling. Full removal of the nerve root is also possible but is less commonly done.
More radical approaches include decompressive laminectomy, a surgery that creates more space for the nerve roots to alleviate pressure, and shunting, where a tube is used to drain fluid from the cyst.
It’s important to note that surgical treatments tend to have higher risks of complications compared to less invasive procedures. These complications could include infection at the site of surgery, new or worsening bladder dysfunction, and failure of treatment.
What else can Tarlov Cyst be?
When dealing with chronic back pain, doctors consider numerous possibilities from a simple mechanical issue to more serious conditions such as a compressed cauda equina and infections—like discitis—or even cancer.
The diagnosis is usually clear based on imaging (like X-rays, MRIs, etc.), but sometimes, it’s not so straightforward. In such instances, conditions that look similar on imaging and may be confused include:
- Dural ectasia: a condition that’s often linked with Marfan syndrome and presents with similar symptoms
- Cancer: a metastatic deposit or nerve sheath tumors, like schwannoma
- Spinal synovial cysts: fluid-filled sacs that may form on the spine
- Meningocele: a type of spinal defect
- Cysticercosis: a parasitic tissue infection.
It’s essential for professionals to consider these possibilities and perform appropriate tests to ensure the correct diagnosis is made.
What to expect with Tarlov Cyst
Treatment of Tarlov cysts generally results in good relief from symptoms, and there doesn’t seem to be a major difference whether you get surgery or a less invasive treatment known as percutaneous treatment. However, Tarlov cysts tend to come back less often in people who have had surgery than in people who have had percutaneous treatment (8% compared to 20%). But, it’s worth noting that people who have had surgery are typically followed up with for a longer time than those who have had percutaneous treatment (38 months vs. 15 months).
When it comes to symptoms getting better, it’s reported that 81% of people who have surgery don’t have symptoms a year later, which is similar to the cyst being completely or substantially smaller in size (79%).
Possible Complications When Diagnosed with Tarlov Cyst
: Complications from cysts are usually rare, but they can include the wall of the cyst breaking or having a hemorrhage or bleeding event within the cyst. These complications can increase pre-existing symptoms or make new ones appear. One such symptom can be radiculopathy, which is nerve pain caused by pressure on the spinal nerves. It can also mimic cauda equina syndrome, a severe condition where the bundle of nerves at the end of the spinal cord are compressed.
In rare cases, bleeding from a hemorrhage in the brain, also known as a subarachnoid hemorrhage, can travel into the Tarlov cyst, causing similar symptoms.
In extremely rare cases, a fracture in the sacrum bone, which is at the base of the spine, could leak contents from within the spinal cord through a Tarlov cyst. This could lead to a sudden cerebral fat embolism, which is when fat particles block blood vessels in the brain.
Lastly, if there’s a hemorrhage within a Tarlov cyst, it might look like intradural carcinomatosis, which is when cancer spreads in the space within the layers of the meninges, the protective covering around the brain and spinal cord. This could lead to unnecessary medical tests and treatments.
Common Complications:
- Cyst wall breaking
- Hemorrhage in the cyst
- Radiculopathy symptoms
- Similar symptoms to cauda equina syndrome
- Subarachnoid hemorrhage bleeding into the Tarlov cyst
- Sacral fracture following trauma
- Acute cerebral fat embolism
- Falsely diagnosed as intradural carcinomatosis leading to unnecessary procedures
Preventing Tarlov Cyst
In order to determine why a patient is experiencing certain symptoms, it’s important for doctors to investigate thoroughly. In some cases, Tarlov cysts (fluid-filled sacs that most commonly occur at the base of the spine) may not be the only reason for the symptoms a patient is experiencing. In this light, other potential causes should also be considered.
Once all possible causes are identified, the patient needs to be fully informed about what to expect going forward. This involves explaining the good and bad aspects of available treatments, the likelihood of the cyst or symptoms recurring, and any associated risks.
To ensure the best possible outcome for the patient, a team-based approach is recommended. This involves various healthcare professionals collaborating and contributing their expertise, helping to improve the overall care that the patient receives.
