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Tarlov Cysts: Symptoms, Diagnosis & Treatment
Audrey Qian • Updated Jul 9, 2025 • 343 hits
Tarlov cysts, or sacral perineural cysts, are cerebrospinal fluid (CSF)-filled dilations that most commonly arise at the junction of the posterior nerve root and dorsal ganglion, appearing as dilations of the distal nerve roots at usually S2 to S4. Although often detected in spinal imaging and proven to have clinical significance, they are generally dismissed or unreported in a differential diagnosis, adversely impacting patients’ health and well-being. Women with chronic pain are disproportionately affected due to implicit gender bias and lack of consensus on management approaches. Neuroradiologist Dr. Kieran Murphy explains the diagnosis, clinical significance, and proper treatment of Tarlov cysts.
This article features excerpts from the BackTable MSK Podcast. We’ve provided the highlight reel in this article, and you can listen to the full podcast below.
The BackTable MSK Brief
• Tarlov cysts are often dismissed in spinal imaging despite evidence that up to 20% are clinically significant and may contribute to CSF leakage, intracranial hypotension and radiculopathy.
• Implicit bias in pain assessment, particularly among women, contributes to gaps in diagnosis, leading to mislabeling of Tarlov cyst-related symptoms as psychosomatic or fibromyalgia. Expending diagnostic sensitivity and clinical empathy are critical for equitable care.
• Accurate diagnosis of symptomatic Tarlov cysts requires stepwise exclusion of other etiologies and a rigorous imaging-based evaluation. Dr. Murphy’s percutaneous two-needle technique offers a minimally invasive therapeutic approach for narrow-necked cysts.
• The growing focus on CSF leaks has raised ethical concerns regarding overtreatment and commercialization of patient syndromes. Clinicians must critically evaluate therapeutic mechanisms and avoid unsupported, speculative interventions.
Table of Contents
(1) Clinical Significance of Tarlov Cysts: Causes & Symptoms
(2) Tarlov Cyst Diagnosis & Treatment
(3) Ethical Considerations for CSF Leak Treatment in Patients with Tarlov Cysts
Clinical Significance of Tarlov Cysts: Causes & Symptoms
The pathogenesis of Tarlov cysts remains unclear, though the currently accepted mechanism of cyst development is the disruption of the CSF-venous drainage system at the perineurium-epineurium junction [1]. Because these cysts are often asymptomatic, they remain frequently mischaracterized and dismissed in spinal imaging. However, up to 20% of Tarlov cyst cases are clinically significant – extensive evidence reports that individuals diagnosed with a Tarlov cyst can experience symptoms, such as lower back pain, numbness in the legs, headaches, and sexual dysfunction [2]. Additional physiologic complications may include intracranial hypotension and CSF leakage.
One of the significant barriers to diagnosing and managing Tarlov cysts and other chronic pain syndromes, particularly in women, is implicit bias. Dr. Murphy believes there is a hyperfocus on high-yield anatomical areas only during imaging, and women with chronic pain are often misdiagnosed or dismissed as fibromyalgia or psychosomatic. This diagnostic gap leads to a cycle of patient marginalization, ineffective pharmacologic treatment, and social isolation. It calls for the importance of attuning to patient narratives, especially when external or objective signs are not present. Additionally, since Tarlov cysts lack any clear external signs, addressing these biases and expanding diagnostic acumen is needed now more than ever to promote equitable care.
[Dr. Jacob Fleming]
The world is ready for the definitive discussion of Tarlov cysts. This is a really fascinating topic in that, as radiologists, especially neuroradiologists, are probably at the forefront for diagnosis of this entity, and yet we get very little, if nothing, in our training about what is the clinical meaning. What actually is this? Tell us, what are Tarlov cysts?
[Dr. Kieran Murphy]
These are dilatations of the dura over the distal nerve roots at usually S234. In about 20% of the people who have them, they're painful, but 80% of people will have pain from something else. It's really important to work out who is the appropriate patient, and systematically exclude everything else before you treat the cyst. They were initially described by Tarlov in McGill in Montreal based on pathologic dissections of cadavers in the anatomy lab in the 1920s, and he published a paper, I think, in 1934 about them. Then they were dismissed, largely, by bald white guys like me, as not significant.
There's gender bias in this. There's dogma in this. Humans are weird. There are things we decide, "That doesn't matter." We have phrases like, "Not uncommon." What does that mean? What is not uncommon? It's common or is it--? We do this to ourselves in medicine all the time, and we overlook things. A good example would be imaging of stroke that focuses on the carotid bifurcation. Why do we look there? It's because we do an endarterectomy or we stent it. We don't look at the rest of the pipe from the apex left ventricle to the MCA branches to look for atheroma.
We focus on certain areas because that's our food source. When we do a lumbar spine MRI, we look at the disc, we look at the end plates, we look at the cauda equina, we look at the nerve roots, and the dura. We don't look anterior to the sacrum, and we don't look at the facet joints much. We don't look for synovial cysts coming off the posterior aspect of the facet joints. We look where the money is, and we have to stop doing that. In particular, in women, these cysts have been overlooked, and for some reason, radiologists took to saying these are asymptomatic.
They're not the easiest patients in the world to look after because many of them have had negative experiences with physicians dismissing them. They've often been through the whole path of gabapentin, Lyrica, oxycodone, and then the worst, fentanyl patches, which you can never get people off.
They've often lost their jobs, lost their families, lost their homes, become isolated, and then they get entrapped in this whole online world of misinformation about Tarlov cysts, where they think the be-all and end-all is to go to a handful of US surgeons for Tarlov cyst surgery. When I see them come back from that, usually they're worse. It's a combination of our behavior, their experience, the commoditization of Tarlov cysts by a handful of mercantile surgeons, and it creates a difficult environment to communicate with that patient openly. I've been looking after people with this for 20 years.
When Don Long, a brilliant chair of neurosurgery at Hopkins, asked me to look after the first few patients. It's not been easy, but it's been worthwhile, and about 70% of these people can be made better. I'm delighted you're interested in this. It's a good example of the fact that it takes about 20 years for things to catch on in medicine.
In those patients, sometimes I see, I'm thinking of two or three in particular.
Particularly one young lady who had tattoos everywhere, really quite terrifying to see, and she was the nicest, kindest person. She was more tattoos than surface area, almost, but when she lifted a heavy object, she would Valsalva. This would push fluid into her presacral dilatation, giving her transient intracranial hypotension. Then, it would recover over the next half hour or so. She eventually died. Some of these people will commit suicide because they have chronic, untreatable, unmanageable pain and no hope. The risk of suicide in this group overall is quite high.
A lot of these folks they have this underestimated, misunderstood, chronic pain at S234, in their pelvis, in their vaginas, in their perineums, down their legs. They've been told they're not symptomatic by orthopedic surgeons, spine surgeons, that this isn't a thing. They've been put on horrible drugs by spine guys who just want to put them on Lyrica and Gabapentin, which are cynical drugs because they do nothing for the underlying condition. They're anticonvulsants that were designed for epilepsy, that Park Davis figured out could be sold for other things even more. They're shit drugs. They're so over-prescribed.
They get depressed. If they're in some place where they don't have a good family doctor and they've no one to communicate and they're isolated, they will kill themselves. It's not uncommon. I hear this once or twice a year. You have to take these things seriously. They're existential for some patients.
[Dr. Jacob Fleming]
Yes. I agree, and it can be difficult, especially in our position. Often we're being referred patients who've been seen by a lot of other physicians. For some reason, and I call it the black pearl, it's that, "Oh, this patient has fibromyalgia." They've been told that. We take whatever that proclamation is as the truth. We continue running with it. We have to have a discerning eye and think, "Is that really true? Is that the source of the problems?" I feel that these patients often end up in that situation, "Oh, yes, they have fibromyalgia. They have a Tarlov cyst, and it all relates to that." They need someone with the diagnostic acumen and ability to say, "Does this make sense?"
[Dr. Kieran Murphy]
I'm a huge fan of the placebo effect. A big fan. I think a lot of what I achieve is thanks to that. We shouldn't underestimate it. I think, to be honest, long COVID teaches us a lot about how people with fibromyalgia are treated, and it's changed their awareness that it's a thing. Again, predominantly women. The other thing is there's a lot to be said for like, gout and a big red toe. You can point to it and go, "That's gout."
[Dr. Jacob Fleming]
Yes, right.
[Dr. Kieran Murphy]
Thank God, it's a sign. I have psoriatic ankylosing spondylitis, and I've had it since 1999. I've been on prednisone and methotrexate and all these things. I got disseminated histoplasmosis after. I was really sick after one of the grumbly mabs. I, first of all, didn't know what was wrong with me. I just thought I was tired. Then I got dactylitis in my left hand. Thank God I did, because you could point to it and show it's abnormal. There's a lot to be said for having a visible clinical sign. Now, with these ladies with Tarlov cysts, if you dismiss the cyst as the cause of the problem, then they have no problem. Then they get bucketed with the fibromyalgias and everything else.
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Tarlov Cyst Diagnosis & Treatment
Identifying which Tarlov cysts are clinically significant requires a thorough evaluation, especially without biases. Dr. Murphy provides a stepwise process of ruling out other etiologies, ranging from degenerative joint disease to gynecologic masses or congenital abnormalities, prior to determining that a patient has sacral perineural cysts. Most of the cases that Dr. Murphy treats are narrow-necked Tarlov cysts, recognized through distinct imaging features, including bone erosion, static high T2 signals, and compression of adjacent sacral nerve roots.
Treatment involves a percutaneous minimally invasive intervention via a two-needle technique inspired by simple fluid mechanics: aspirate fluid through a deep 18-gauge spinal needle while venting through a superficial needle to avoid vacuum resistance, then carefully inject fibrant sealant.
[Dr. Jacob Fleming]
So much to unpack with the significance of the Tarlov cysts. A difficult population and often their imaging is read as essentially negative, and perhaps the only thing that's mentioned out of the ordinary is Tarlov cyst, so a lot of these patients somewhat naturally latch on to, "This has to be the cause for my symptoms." As you said, it is some of the time. Tell us about how you tease that out a patient who's come to you and said, "I have a Tarlov cyst?" How do you tease out, what are the symptoms? Is the cyst causing it? How do we go from there?
[Dr. Kieran Murphy]
First of all, I get all my patients - their GP has to send the referral, their family doctor. I have to get a formal referral from that person, not the person referring themselves. I practice now in Canada, in Toronto, where we have a socialized system. My salary doesn't change whether I treat 1 or 200. We get the referral, then I review their imaging, then I have a consultation with them. Reviewing outside imaging in itself is a pain because you've got to figure out how to read that CD or how to download that thing from Public Health or whatever. Then, we talk.
I divide the patients into those who have pain from something else and those who may have pain from their cystic dilatation of distal or caudal sacral nerve roots. I look for other causes of low back pain, radicular pain. There will be a handful of people who have a congenital anomaly. They will have some ligamentous laxity, and they will have perineural cysts all the way down. On sagittal T2, I'll look at the C-spine, T-spine, C of each little neuroforaminal has a light bulb in it, some dilated perineural cyst.
[Dr. Jacob Fleming]
Neurolactasia, yes.
[Dr. Kieran Murphy]
Then you know already, there's something more systemic going on here. Then I look in the sacrum for degenerative disease, for set joint disease in particular. Many of these people cannot sit. I look anterior to the sacrum for fibroids, ovarian masses. It's amazing how many have been missed, or piriformis syndrome, or ischial vine tuberosities, or irregularities, or spicules of bone or other things, and prior trauma to the sacrum, where somebody might have fallen out of a tree when they were a kid, but now at 52, they've got an abrupt angulation at S34 and they've got pain from that.
You have to go through step by step to figure these things out. In terms of the anatomy of the sacral abnormality, because it's usually S234, Tarlov cysts are a particular narrow-necked entity with minimal communication with the subarachnoid space around the distal caudal nerve roots. There are meningeal diverticula, which are wide-necked communications which are really form fruits of sacral agenesis or digenesis.
You'll have these big dilated distal, sacral, dural, CSF-filled sacs that directly communicate with the nerve roots around the distal spinal canal. Sometimes you'll see a lipoma of the phylum terminale going into them, and you do not treat those. They were built like this. It's the way that person is built. Their pain may be from something else. There will be people with erodent loss or Marfan's or Loeys-Dietz who have enormous duralectasias, and sadly, there is nothing you can do for them. That's a case of waiting for reincarnation.
Now, the ones that I treat, I can define as the cause of the symptoms. They will be narrow-necked. Usually, they've eroded bone around them. The signal on T2 is going to be higher in the cyst than the adjacent subarachnoid space because it's not recessing. It's not moving. You've got static CSF. It'll be slightly brighter on T2.
The bone erosion is fascinating because you're talking about CSF pressure in a cyst and pulsating with each cardiac output, because the brain's a pump. This erodes cortical bone over time. You're talking about millimeters of water causing bone erosion. That's really unusual. Normally, you're talking about mercury and sphygmomanometers and that level of pressure, not millimeters of water. The bone erodes, I think, the distended dura around the cyst, is the cause of the pain because it's referred from the dural innervation of the cyst. Often, when I pass my needle through that dura, they reproduce their pain. That's really reassuring.
If I'm not sure, I will do nerve root blocks around the nerve that is compressed. Usually, this is S2. The S2 adjacent nerve that's compressed can be flattened and ribbon-like between the cyst and the adjacent bone. When you deflate the cyst and treat the cyst, you see that formerly ribbon-like nerve becomes plump again and slightly oval. The symptoms go away. As the cyst retracts and shrinks, that nerve will re-expand. I firmly believe that these patients, I treat them a bit like gardening. You don't finish your garden in one day. If you try and do everything at the one time, you can hurt people.
Our job is not to make people worse. I will stage things if I have to. Aspirate the cyst, put in half or one cc of 1% lidocaine to see if there's symptoms. If that works, then I use that two-needle technique that I described, which is really simple.
[Dr. Jacob Fleming]:
Yes. I wanted to hear you talk about it. I think this is one of the compelling things.
[Dr. Kieran Murphy]:
Yes. The first one or two patients I treated, I caused them more pain than anything else I've done. When you try and aspirate liquid out of a closed space, you can't. Then at two, three, in the morning, I just thought of how we get detergent out of a big detergent bottle. There's a vent. How we used to drink beer by putting two holes in the can. That's how I thought I'll put in two needles and take the stylet of both out. One goes deep, one is relatively superficial. Aspirate from the deep one, get an air fluid level. If the air fluid level stays over about three, four, five minutes, you know it's a narrow neck cyst that's not going to refill, and you can safely put Baxter to seal fibrin into it.
I add probably half a cc of 1% lidocaine up front just to decrease post-operative pain because the fibrin can cause some inflammation. Now, is this on-label or off-label? To discuss that. Baxter's fibrin has been used for years as a dural sealant for spine surgery. I think it's arguable. It's a bit gray. We do need a better dural sealant. All this work on CSF leaks tells us we need a better dural sealant. I've been fortunate enough to be asked to work on a better one that looks interesting. It works and it's safe. That's the technique. Two needles, one deep, one superficial, air fluid level, weight, then put in fibrin.
I put in about 80% of the volume of CSF that I aspirated because there will be some inflammatory reaction. How do I get the needles in? The lamina usually will have a defect in it from the chronic expansion of the cyst and the erosion of the bone. I find that defect and put the needles in through there. I find the place of most thinned lamina, and I just use conventional 18-gauge spinal needles, and I get them to go through that thinned lamina by spinning them at my fingertips. Very little pressure. Just spin them, and it will go through the lamina.
You put in one, they experience their typical pain. You put in the other, then you aspirate. That's all there is to it. What's the retreatment rate? About 20 to 30% after a few years. Because I don't move my job. I've only had two jobs. 10 years at Hopkins, 15 years in Toronto, I have a longitudinal follow-up on people. Over time, you see the cyst shrink and shrink and shrink and go away. These folks will let you know if they have recurrences or other things happen. That's all there is to it. It's pretty simple.
Ethical Considerations for CSF Leak Treatment in Patients with Tarlov Cysts
When they become symptomatic, Tarlov cysts can cause CSF leakage. An interest in CSF flow disorders has been growing within neuroradiology, and so too does the concern about the ethical implications of overdiagnosis and commercialized treatment. CSF leaks often manifest as chronic headaches in patients without clear imaging evidence, increasing the risk of speculative intervention. According to Dr. Murphy, they have been increasingly used as catch-all explanations that result in the commercialization of headache treatment and the broad overuse of interventions like fibrin glue patching without precise localization or justification. With this awareness, clinicians must resist such trends by questioning their own biases and being conscious of the mechanism of action behind every treatment.
[Dr. Kieran Murphy]
I actually think we have an ethical issue with over-treatment of people's headaches and it being turned into a cash cow by centers who are commercializing that. We need to be careful with that. There are more trial and assist patients out there looking for care than there are people with CSF leaks. Yet all the focus is on CSF leaks. Why is that? It's money. I've seen this once or twice before. Y90 is a good example. I think those institutions that are turning these patients into their product line and charging outrageous sums should be subject to some ethical oversight.
[Dr. Jacob Fleming]
Absolutely. Yes.
[Dr. Kieran Murphy]
There needs to be better patient selection.
[Dr. Jacob Fleming]
I agree with that. I trained in an institution that at the time had a very vigorous blood patching program. The neurologist who was there at the time was one of these experts in CSF hypotension. A lot of the patients that you've alluded to multiple times now, these patients have been put through it and bounced around.
[Dr. Kieran Murphy]
Yes, to separate out the Tarlov cysts, I think that we can define with a dermatome distribution what is causing the problem. When you start to get into this whole weird world of cranial cervical instability and chronic headaches, and imaging negative CSF leaks and headaches being so common, and so many reasons for headaches. I don't mean to dismiss the suffering of people with these problems or any of the other functional abnormalities that people suffer from. These are terrible complaints to have. They are terrible diseases to have. The commercialization of them is an ethical issue. We've had this before in medicine. It's not uncommon.
I constantly look at what we do with a certain level of functional circumspection to make sure that I'm trying to do better. I worry about this whole headache thing. I've sat in the back of those meetings. One person was asked about how many allergic reactions they'd seen to fibrin glue. This person said, "Well, I've-- Oh, I've injected, probably, Fibrin 2000 times." I'm thinking that means you don't have a target. You don't know where you're putting it. You don't have a specific location to put that fibrin.
If you're putting fibrin at every level, whether it's a perineural cyst in somebody's T-spine, you don't know what you're doing. As neurodivergentalists, if I'm off by a millimeter, something goes haywire. I think we have to look at the technique, we have to look at the implant, we have to look at the logic, we have to look at the culture of what's going on, and get more specific and get more focused. It's always about the implant. It's always about the mechanism of action.
[Dr. Jacob Fleming]
That's so thought-provoking, everything that you just said. It makes me think about, we talked about, the commercial aspect. How does that inform what has a future for improvement, for treatment for Tarlov cysts?
[Dr. Kieran Murphy]
We need a better-- First of all, I'm fascinated by CSF. We don't think about liquids. We don't think about liquids much. I'm fascinated by synovium. I know that sounds bizarre. Do you think the synovial fluid at occipital C1 is the same as the synovial fluid in your ankle?
[Dr. Jacob Fleming]
No, probably not.
[Dr. Kieran Murphy]:
No, it wouldn't be. If you've got a car, you're going to have gearbox oil in the gearbox, you're going to have axle stuff on the axle, you're going to have different fluids lubricating the engine. When we look at Synovest, why is it the same everywhere? Should we not actually study the synovium, the synovial fluid in different locations, and see what is specific to that? When you think about a Tarlov cyst, why is the CSF like that, and what is it doing, and what can it tolerate being in there with it? Now, sadly, nerves only like CSF. If there's a nerve in that cyst or in the wall of that cyst and I put fibrin in there, it's going to get pissed off.
I need to come up with a fibrin sealant, a dural sealant, that does not cause a neuritis of some kind by being a foreign body. When people are treating CSF leaks, they need to have a material that does that as well. Adhesives to dura shuts the hole because fibrin's not very adhesive, and actually solves the problem, and be really specific on what they're doing.
Podcast Contributors
Cite This Podcast
BackTable, LLC (Producer). (2025, April 8). Ep. 74 – Diagnosis & Treatment of Tarlov Cysts [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
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