Tarlov Cyst (Perineural Cyst)

Tarlov cysts, also called perineural cysts, are fluid-filled sacs of cerebrospinal fluid that form on spinal nerve roots, most often in the sacrum at the S2 level [Source]. Most are found by chance on an MRI and cause no symptoms. This guide explains what a Tarlov cyst is, when it matters and what can be done about it.

Basic Anatomy of Tarlov Cysts

A Tarlov cyst is a pocket of cerebrospinal fluid (CSF) that forms inside the covering of a spinal nerve root. It sits between two thin nerve layers, close to the dorsal root ganglion, a cluster of nerve cells near the spine [Source]. Nerve fibers can run through the cyst [Source]. That is one reason treatment needs care.

A Tarlov cyst is not a tumor. It is also different from a facet joint (synovial) cyst, which grows from a small joint in the back of the spine.

Tarlov Cysts in the Sacrum

The sacrum is the triangle-shaped bone at the base of the spine. Its nerve roots are numbered S1 to S5. Sacral Tarlov cysts are far more common than cysts higher in the spine, and S2 is the most common level [Source]. A sacral cyst sits near nerves that serve the buttocks, the back of the legs, the pelvic floor, the bladder and the bowel.

What Causes Tarlov Cysts?

The cause is not fully known. Experts think changes in the nerve covering and in spinal fluid flow or pressure may play a part. One idea is that a tiny opening lets fluid into the cyst more easily than it can leave [Source]. An MRI usually cannot show why a cyst formed.

How Common Are Tarlov Cysts?

Tarlov cysts are found in about 4 out of 100 people who have spine imaging. A 2021 meta-analysis of 22 imaging studies and 13,266 people found a pooled rate of 4.18% (95% CI 2.47% to 6.30%). Cysts were more common in women than in men [Source].

Having a cyst does not mean you will need treatment.

Clinical Presentation: Tarlov Cyst Symptoms

When a cyst does cause problems, the symptoms follow the nerves it presses on [Source]. They may include:

• Sacral or buttock pain: aching low in the back, over the sacrum or near the tailbone.
• Trouble sitting: pain that builds when you sit for a long time.
• Nerve pain in the leg: burning, tingling, numbness or sciatica-type pain.
• Pelvic or perineal symptoms: pain or changed feeling in the groin, genitals or the area between the legs.
• Bladder, bowel or sexual changes: such as urgency, constipation or changes in sexual function.

These symptoms are not unique to Tarlov cysts. Disc problems, a pinched nerve root, sacroiliac joint dysfunction, tailbone pain (coccydynia) and pelvic conditions can cause the same complaints. More than one problem can be present at once.

Are Tarlov Cysts Dangerous?

Most Tarlov cysts are not dangerous. They are benign, which means they are not cancer [Source]. A cyst becomes a concern only when it seems to press on nerves and cause symptoms.

Warning Signs That Need Emergency Care

Go to the emergency room for new trouble passing urine, new loss of bladder or bowel control, numbness in the groin or “saddle” area, or leg weakness that gets worse quickly. These signs need urgent care, whether or not you know you have a cyst. See when back pain is an emergency.

Work-Up and Diagnosis

Imaging finds the cyst, but deciding if it causes your symptoms takes more. A specialist looks at the MRI images, your history and a careful nerve exam together.

• Dedicated sacral MRI: a routine lower back MRI may not show the whole sacrum well.
• CT or CT myelography: used in some cases to check bone changes or how the cyst connects to the spinal fluid space [Source].
• EMG and nerve conduction studies: can look for nerve damage, but a normal test does not rule out a sacral nerve problem.
• Bladder or pelvic tests: may help when urinary or pelvic symptoms are present.

Does Cyst Size Decide Treatment?

No. There is no single size cutoff. A large cyst can cause no symptoms, while a smaller one can matter. Symptoms, exam findings and the cyst’s shape are weighed together.

Tarlov Cyst Treatment Without Surgery: Your Options

Most people with these cysts never need a procedure. When treatment is needed, care usually starts with the simplest, safest steps [Source]. No option works for everyone.

• Watching the cyst: a cyst with no matching symptoms usually needs no treatment.
• Activity changes: pacing activities, taking sitting breaks and using cushions may ease pain.
• Physical therapy and pelvic floor therapy: can improve movement and comfort, but do not shrink the cyst.
• Medicines: for nerve pain or inflammation, chosen with your doctor based on your health history.
• Image-guided injections: may give short-term relief and help show where pain comes from, but they do not reliably shrink the cyst [Source].
• CT-guided aspiration: a specialist drains fluid with a needle. Relief may be short-lived because the cyst can refill [Source].
• Aspiration with fibrin sealant: the cyst is drained and then filled with a medical glue to help stop it from refilling.

In a study of 213 patients treated with aspiration and fibrin sealant, 81.8% of those followed were satisfied at one year and 74.0% were satisfied at three to six years [Source]. This was an observational study from one center, and satisfaction is not the same as full recovery. A cyst with a wide opening to the spinal fluid space is usually not suitable for fibrin sealant [Source].

When Is Surgery Considered?

Surgery is considered when symptoms clearly match the cyst, other causes have been ruled out and nerve problems or disability are serious. Surgeons may open the cyst wall (fenestration) or fold and tighten it (imbrication) while protecting the nerve fibers that run through it [Source] [Source].

In a study of 97 patients who had surgery, 76.0% reported good or excellent improvement, and the complication rate was 17.5% [Source]. This was a retrospective study. Risks include spinal fluid leak, ongoing pain and new bladder, bowel or sexual problems [Source].

Living With a Tarlov Cyst: What to Avoid

There is no standard list of activities to avoid. Pay attention to what reliably makes your symptoms worse, such as long periods of sitting, and adjust those activities. Do not ignore new bladder, bowel or weakness symptoms.

Questions to Ask Before a Procedure

• Which symptoms and exam findings suggest this cyst is the cause?
• Does the cyst’s connection to the spinal fluid affect the plan?
• How much experience does the specialist have with this procedure?
• What are the likely benefits, the main risks and the chance of needing more treatment?

Tarlov Cyst Evaluation at SpinePain Solutions

At SpinePain Solutions, Dr. Amit Sharma, Chief, Division of Pain Medicine at Good Samaritan University Hospital, offers evaluation and treatment options for back, buttock and nerve pain, including pain linked to a Tarlov cyst. The first step is finding out whether the cyst, another problem or both explain your symptoms. For selected patients whose symptoms clearly match the cyst, Dr. Sharma offers image-guided Tarlov cyst aspiration, with or without a fibrin sealant injection. The cyst can refill, and every procedure has risks, so you decide together after talking through the possible benefits and risks.

Bring your MRI images, reports and a short timeline of your symptoms. We see patients at our Bay Shore, Commack and Farmingdale offices (see office locations). Call or text 631-310-0000.

Frequently Asked Questions

What is a Tarlov cyst?

A Tarlov cyst is a small sac filled with cerebrospinal fluid (CSF) that forms on a spinal nerve root, most often in the sacrum. Most Tarlov cysts are found by chance on an MRI and cause no symptoms. A few press on nearby nerves and cause pain or other nerve problems.

Is a perineural cyst the same as a Tarlov cyst?

Yes. Perineural cyst and Tarlov cyst are two names for the same thing. The cyst forms within the covering of a nerve root. It is named after Dr. Isadore Tarlov, who first described it in 1938.

What does a Tarlov cyst at S2 mean?

S2 is the second level of the sacrum, the bony base of the spine. It is the most common place to find a Tarlov cyst. On its own, a cyst at S2 does not mean it is causing your pain. A specialist compares the MRI with your symptoms and exam.

Are Tarlov cysts dangerous?

Most are not. Tarlov cysts are benign, which means they are not cancer, and most need no treatment. Seek emergency care for new trouble urinating, loss of bladder or bowel control, numbness in the groin or saddle area, or leg weakness that gets worse quickly.

Can a Tarlov cyst cause sciatica or pelvic pain?

Yes, a cyst that presses on a nerve can cause buttock or leg pain, sacral pain, or pain and numbness in the pelvic area. These symptoms have many other causes too, so a cyst on an MRI does not prove it is the source.

What size Tarlov cyst needs surgery?

There is no single size that means you need surgery. Doctors look at your symptoms, exam, nerve tests and the shape of the cyst together. A large cyst can be harmless, and a smaller cyst can sometimes cause symptoms.

How are Tarlov cysts treated without surgery?

Options include watching the cyst, pacing activities, physical therapy, pelvic floor therapy and medicines for nerve pain. In selected patients, specialists may use image-guided injections or image-guided aspiration, with or without fibrin sealant. SpinePain Solutions offers both types of aspiration for selected patients. None of these work for everyone.

Can Tarlov cysts come back after treatment?

Yes. Fluid can build up again, especially after aspiration alone. Symptoms can also return after fibrin sealant or surgery. No treatment can promise lasting relief.

Does physical therapy shrink a Tarlov cyst?

No. Physical therapy does not shrink the cyst. It may help you move better, sit longer and manage muscle or pelvic floor problems that occur with it. Exercises that keep triggering nerve pain should be changed.

Medical References

1. Klepinowski T, Orbik W, Sagan L. Global incidence of spinal perineural Tarlov’s cysts and their morphological characteristics: a meta-analysis of 13,266 subjects. Surg Radiol Anat. 2021;43(6):855-863. doi:10.1007/s00276-020-02644-y. PubMed.
2. Murphy K, Nasralla M, Pron G, et al. Management of Tarlov cysts: an uncommon but potentially serious spinal column disease. Review of the literature and experience with over 1000 referrals. Neuroradiology. 2024;66(1):1-30. doi:10.1007/s00234-023-03226-6. PMC.
3. Murphy K, Oaklander AL, Elias G, et al. Treatment of 213 patients with symptomatic Tarlov cysts by CT-guided percutaneous injection of fibrin sealant. AJNR Am J Neuroradiol. 2016;37(2):373-379. doi:10.3174/ajnr.A4517. PubMed.
4. Abdi D, Huttunen J, Leinonen V, et al. Operative treatment of Tarlov cysts: outcomes and predictors of improvement after surgery. A series of 97 consecutive patients and a systematic review of literature. Global Spine J. 2025;15(2):1041-1048. doi:10.1177/21925682231221538. PubMed.
5. Fletcher-Sandersjöö A, Mirza S, Burström G, et al. Management of perineural (Tarlov) cysts: a population-based cohort study and algorithm for the selection of surgical candidates. Acta Neurochir (Wien). 2019;161(9):1909-1915. doi:10.1007/s00701-019-04000-5. PubMed.
6. Lim Y, Selbi W. Tarlov cyst. In: StatPearls. StatPearls Publishing; 2023. PMID 35881759. NCBI Bookshelf.
7. American Association of Neurological Surgeons. Tarlov cyst. AANS.
8. National Institute for Health and Care Excellence. Therapeutic percutaneous image-guided aspiration of spinal cysts (HTG143). NICE.

Related resources: spinal nerve conditions, nerve pain, sciatica, back pain.