AAN 2026 | Could a subset of sacral Tarlov cysts be misdiagnosed chronic sacral CSF leaks?

This research is particularly exciting to me right now. I think that if you’re at all familiar with imaging in the spine, you might have heard of something called sacral Tarlov cysts. These are cystic lesions that are in the sacrum that are traditionally conceptualized as benign and incidental. They occur more often than women. They’re very, very commonly seen on routine spine MRI. And certainly as a radiologist in training, I was told that these are not something that we should really pay attention to in a report. Simply just mention it and move on. Meanwhile, we have this phenomenon of spinal fluid leaks that occur throughout the spine. But for some reason, peculiarly, sacral CSF leaks have seemed to be the most rare of any type of CSF leak. And this is despite the fact that as upright individuals, the pressure is the highest in the bottom of the spine in the sacrum. The dura there, if you ask any neurosurgeon, is incredibly thin with very little epidural fat cushioning that dura. Yet the CSF leaks in the sacrum are incredibly rare. So that seemed very peculiar to me. So we organized a multicenter study across the United States, Europe, and Australia to look to see, you know, how common are these? Let’s find real sacral CSF leaks that we’ve all found together and look at what these patients look like pre and post treatment. How do they do with treatment? And where do we go from here? And what we found is that many of these patients will start with what looks like a traditional spinal fluid leak. There’s fluid emanating from the intradural compartment into the epidural space. But after a treatment, particularly one that was not completely effective, they develop a cystic structure which looks indistinguishable from the sacral Tarlov cyst. And when they are taken to surgery, they have a persistent leak there. And so what this proves counterfactually is that there are some of these lesions, which we are calling Tarlov cysts, benign perineural meningeal diverticula, that are actually chronic sacral CSF leaks, which would then make a lot of sense in terms of how we are seeing so many patients who fall into an overlapping demographic of patients with sacral tarlov cysts who have orthostatic headaches in a CSF leak phenotype that actually just have chronic CSF leaks that all of us have been looking right in the face of and missing all along. And so this is particularly exciting because of the widespread prevalence of sacral Tarlov cysts. Certainly not all of them are chronic CSF leaks, but even if a small fraction of them are, that is millions and millions of people that could potentially be helped in the future.

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