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Moderator: For our first talk of Bridging the Gap 2025, we have Professor and Dr. Jurgen Beck, director and chair of the Department of Neurosurgery at the University of Freiburg in Germany. And I’m the patient moderator for this section. My name is Jen MacKenzie, and I’m a recovering PDPH patient who, after having a very long-term spinal CSF leak, was eventually repaired through surgery. And I’m currently volunteering on the board of directors at the Spinal CSF Leak Foundation.
Dr. Beck, we’re very glad to have you here today presenting on such an important topic as PDPH. Please begin when you’re ready.
Dr. Beck: Good morning everyone. I hope you can hear me, you can see me, and if all good. First of all, I would like to thank Andrew Callen and the Spinal CSF Leak Foundation for making this possible. I’m very honored and very proud to be here in this, I always call it, a family with the colleagues and also the patients, and that we have so much time to spend this whole morning, or afternoon in Germany, with some conundrums and some progress we have made in spinal CSF leaks.
This is Freiburg and Black Forest. This is our medical center where we have the benefit to have all necessary specialties, neurology, neuroradiology, neurosurgery in one building, and this is what you can see here.
The topic is about post-dural puncture headache, but of course has a lot in common with spontaneous intracranial hypotension, and both diseases or both disorders are primarily orthostatic headache disorders, as you can see here. And despite the common clinical presentation, of course we have to take into account that the etiology is different. In post-dural puncture headache, we have always iatrogenic needles that entered, intendedly or unintendedly, the thecal sac, versus in spontaneous intracranial hypotension, the disease starts spontaneously.
And if you look at the definition of the International Classification of Headache Disorders, it is still a little bit neglected because there is no such thing as a persistent or a chronic post-dural puncture headache. Currently it is defined that after a dural puncture, intendedly or unintendedly, if you get headaches within 5 days of the lumbar puncture, then this is caused by CSF leakage. Please keep that in mind. We come back to that later. And then you have post-dural puncture headache, and usually it should stop after two weeks or earlier after sealing with an epidural blood patch.
So what our patients, what many of you and many of us physicians are dealing with, is not really defined in this, at least not in this… in this International Classification of Headache Disorders.
But of course we do see many, many patients with chronic or persistent post-dural puncture headache. And not only that we see these patients, and not only that you are affected with this disorder. There is a growing body of literature and evidence that this disorder does exist, and that as well it is possible that the onset of the disease is later than 5 days after a dural puncture, and of course that symptoms might very well be prolonged and last longer than 14 days or last even after a blood patch.
So on the other hand, it is a quite severe disease and it is accompanied with a lot of signs and symptoms that might change a little bit over time. It’s different immediately after a lumbar puncture, an intended or unintended lumbar puncture, where you have clear orthostatic headache and neck pain and tinnitus, and then it’s changing a little bit into more fatigue or reduced quality of life, symptoms that resemble depression, and even severe sequelae like subdural hematomas. And if you ask the patient group, it’s a severe disease and it’s changing completely their current life, and patients and affected patients lose their jobs, lose their families, lose their joy of life. So it’s a full spectrum of a severe chronic disease.
One thing I have learned in this family, in this spinal CSF leak family and professional community, is that it does matter what kind of needle you are, as a physician, you are taking when you do an intended lumbar puncture. And it really does make a difference if you look at the tip of these needles, whether it’s beveled and it’s sharp, or whether it’s kind of a pencil-tip needle where the opening is at the sides of the cannula and not at the tip with a sharp edge.
This is nicely demonstrated here, that it does make a difference whether you enter the thecal sac with a pencil tip or with a sharp tip, where you cut out a piece of dura, and the remaining hole is way smaller in a pencil-tip needle than in a beveled sharp needle. And this is supported by numbers now. So you can reduce the number of post-dural puncture syndrome from 11% to 4.2%, by just using the modern appropriate needles that are not beveled at the tip, that are pencil-like at the tip. And this has been validated and again put into a nice paper that needle type has a high level of certainty that we can harm our patients using the sharp beveled needles, as well as the size of the needle. So it’s rather simple. The smaller the better for preventing post-dural puncture headaches and post-dural puncture syndromes.
This is an aggressive-looking image, but this is just the form of the beveled cannula that has entered the dura, as nicely depicted by electron microscopy, that you can see when the needle is sharp you do more harm than when you use a blunt pencil-type needle.
Again, there’s more and more data that also this chronic or persistent form of post-dural puncture headache exists. And this is not a real systematic overview, but it’s just what we encountered two or three years ago. We just put together how severely affected our patients are. On the one hand, it’s clearly there is a huge bias because we are a referral center, and patients that are severely affected come from all over Germany, Europe, and the world to our place in Freiburg. But on the other hand, you can clearly see it is not a harmless disease. These patients have been on sick leave for over a year on average, have seen at least five doctors, were hospitalized in at least five different institutions, and have been even one month in acute hospital care.
This is another paper that shows how severely affected post-dural puncture patients are. This is a survey Ali Kapan has made and published in Headache last year. And don’t focus on the single numbers. It just gives you an overview that once you are affected with this post-dural puncture syndrome, the capacity to do your job full-time in the same job, in the same work you have been before, is only 12%. So roughly only every tenth patient can return to his same job. Or to put it in another very impressive number, the ability to take care of your own children the whole day, only 12.8% of the affected patients were able to do that.
Something that is known up to now is where does it come from, how do we approach patients after intended or unintended lumbar puncture. And there was this arachnoid bleb sign. This is a very subtle sign that you can see here where the arrow points to, and in the sagittal MRI you have this small tiny little bleb, and this is really something that does exist.
This is a case here with one, two, three, four, five blebs, and all these blebs really have been some forms of leak locations once we did surgery on this patient. On the other hand, another sign that has been proposed and propagated is the so-called dinosaur tail sign in patients, even when the MRI of the brain looks normal in patients after post-dural puncture, that there are some of these wide structures here that we have to make more visible here with the red dots. These are some structures, some fluid structures that accumulate here beneath the ligamentum flavum and make the sagittal spine look like the tail of a dinosaur, as it was put in the publication of Sakurai in Headache 2017. This is where the name of this sign comes from. It should resemble the tail of a dinosaur. This is why it’s called the dinosaur tail sign, and this is supposed to be more prevalent in post-dural puncture. But to give you our impression, it is not. This is just experience-based up to now, but the dinosaur tail is very, very often present in completely healthy patients, even in individuals that never have seen a dural needle or underwent a dural puncture. So this is not a very good sign.
But now coming to the new evidence that is available, and Andrew has asked me to report a little bit about two papers that have been published recently, one about imaging and one about CSF dynamics. What is really going on? What do we see on imaging when we have a post-dural puncture patient, and what really is going on in the CSF system? What about the pressure and the CSF dynamics?
Of course, thanks to my team, we are able to produce these data and to produce these numbers, and also thanks to all the patients and families and caregivers that have been involved in these studies. Without you, that would not have been possible.
I’ll give you some numbers now. So Charlotte Zander was very clever to put this together. What is actually going on in imaging if you have a post-dural puncture headache? And this was a general overview and, of course, also utilizing the Bern score, just to have a uniform language all over the world where the Bern score is used. How does this relate to post-dural puncture? The Bern score is now kind of a standard in spontaneous intracranial hypotension. So how does it look in post-dural puncture syndrome?
And unfortunately, there is not much going on. You can have an MRI that completely looks like SIH, a CSF loss syndrome, with a large pituitary, downward displacement of the brain, sagging of the brain, enlarged venous systems, and you can have a completely normal MRI in post-dural puncture. This is striking, and there’s a big difference as compared to SIH, and this is probably one of the main messages of my talk: a normal brain MRI does not rule out post-dural puncture headache syndrome.
This is, for instance, an example given. Two patients, both after peridural anesthesia while in labor, and one MRI is clearly positive and one is clearly negative. And unfortunately, in PDPH, most of the scans are negative.
But we also, Charlotte Zander and our team, looked at the spinal findings. And this is very interesting because this is really where the crime scene happens, so to say, where the action takes place. And unfortunately, you don’t see much evidence of CSF leaking either. But if you look clearly here, you have a kind of a ventral—this is the ventral side—these are the spinal vertebrae, this is the spinal cord, this is the CSF space that is normal, and here in front of it you have a ventral fluid deposit outside of the thecal sac, which is clearly pathologic. Here now shown with the red arrows, this is CSF where it does not belong. This is a positive spinal MRI.
And this now is the corresponding post-myelo CT, and you can see here this cap of white stuff here. This again is contrast media, so this is CSF outside of the thecal sac, but interestingly not here where the spinal needle enters during the lumbar puncture, but on the other side, on the ventral side.
And these are now clear numbers. This was positive in our study, which included, I think, almost 100 patients, 88 or 90 patients, in 12% of patients with post-dural puncture headache.
This is an overview of the results of this study. So as I’ve shown you just a second before: epidural fluid was present in 12% of the patients, and interestingly only at the ventral side, opposite to the side where the spinal needle enters the thecal sac.
There was not one case, not one MRI, where there was clear free fluid on the dorsal side of the thecal sac. And the other striking finding is that, as opposed to spontaneous intracranial hypotension where we have a high Bern score, where we have a lot of signs that Wouter Schievink has described and others — brain sagging, enhancement of the meninges — we can clearly find in most of the patients with spontaneous intracranial hypotension. It’s the other way around in post-dural puncture headaches. So the Bern score is very low if we exclude these positive patients, rather 0.9 or 1, so rather normal.
Meaning: is post-dural puncture headache an MR diagnosis? No, it’s not. This is really, I think, a clear message and a strong message. In most patients, you don’t see it on imaging, neither on brain imaging nor on spinal imaging. And to put it in other words, does negative imaging rule out post-dural puncture headache? No, it does not. Negative imaging, a negative MRI, does not rule out post-dural puncture headache or syndrome.
This is also reflected in what anesthesiologists currently propose. It’s not an imaging diagnosis, it’s a clinical diagnosis. But on the other hand, do we image or shall we image patients with this syndrome? Yes, of course we shall. Especially in this group of patients and doctors and caregivers in some specialized centers where patients approach us asking what’s going on now. Of course we shall image because if there are atypical symptoms — and by definition symptoms longer than 14 days are atypical symptoms — so if a chronic PDPH develops, and of course in CSF centers, and even if you consider surgery or surgical exploration, you do need an MRI of the spine and the brain.
And one finding again that was also present in this study was the arachnoid blebs. They were present in the study of Charlotte Zander in 9% of the patients. So it is also a little bit disappointing that we have probably one clear sign, but we had a very well-defined cohort of almost 100 patients with post-dural puncture headache, and in only 9% we did find an arachnoid bleb that looks like this was the very spot of the bleb on imaging. Now you can see here that the CSF is oozing out next to the bleb and washing away the blood that has accumulated, so we called it weeping dura that you can remember very easily. So this is a clear sign on imaging, but unfortunately it is only positive in 9% of our patients.
Now switching to the CSF system, to the CSF dynamics, we utilized a procedure that was invented in the 1970s in kids, in the pediatric population for hydrocephalus, and this is the measurement of how the system reacts to a volume load that is injected into the spine, into the spinal dura. So once you insert the needle into the thecal sac and you start infusion of Ringer or saline here, there is an increase in the slope in the pressure that we can measure with the same or a second needle until it reaches a plateau. This is a normal reaction. This is a normal curve, and this was used heavily for diagnosis of normal pressure hydrocephalus in kids.
And we transferred this in 2017 to spontaneous intracranial hypotension. So this is now spontaneous several spinal CSF leaks, and you can clearly see again this normal curve, as I’ve shown you a second ago, and a clearly different-looking curve, a completely pathological-shaped curve. This goes for spontaneous intracranial hypotension, and it kind of makes sense. If you have a system with a hole in it, it reacts differently to a fluid, to a volume overload. And we wanted to test this in post-dural puncture as well, of course. How does it look like?
And just to give you some numbers for the spontaneous CSF leaks, there was a clear benefit. The false negative rate was clearly lower than in just regarding the opening pressure, and the area under the curve for the resistance to CSF outflow was increasing our diagnostic accuracy, and it was investigator independent and showed a specific pattern of CSF dynamics once the dura has a hole in it. And the Rcsf out, the resistance to outflow, was the best diagnostic parameter. But, and this was very interesting in 2017 already when we first tested it, there is a clear difference whether you test patients acutely, subacutely, meaning within one year, or even later than one year.
So, and if you looked at the numbers again, this only goes for spontaneous spinal CSF leaks. In the acute phase, meaning less than 10 weeks, everything is straightforward. The resistance is very low, pathologically. After 10 weeks, it’s 50/50. And after one year, more patients do have an increased resistance to CSF outflow despite having still an open hole in the dura. This is tough to grasp, but these are the results. And this gives us a clear time dependency.
The same data just shown otherwise. So in the acute phase, you have five as the threshold. You have a very pathological threshold in the acute phase. In a subacute phase, it’s rather normal. In the chronic phase, it’s even resembling patients with normal pressure hydrocephalus. Nobody is fully knowing what’s going on. But please keep this in mind when we now interpret the data for post-dural puncture headache. Timing does matter. Time matters for spinal leaks.
And this was also true for treatment that you do. If you treat patients with spontaneous leaks early, they have a very, very high chance of completely resolving the symptoms, and if it is done years or decades after, the chances are lower.
So now the interesting stuff for chronic post-dural puncture headache. We did repeat the same study now in patients with post-dural puncture headache and not with spontaneous CSF leaks. And we were able to include 21 patients, which is quite a lot because, as you can all understand, if you are affected by a disorder that has changed your life completely after someone stuck a needle in your dura, we want to repeat this using smaller needles, but we want to repeat this. So we were lucky that a lot of patients agreed to do that, and we have data for 21 patients now.
These are the numbers, and symptom duration is important, as I have shown you. So 21 months. So this is a real chronic patient group. And again, as in Charlotte Zander’s youngest publication, almost all these patients had a normal brain MRI and a normal spine MRI. Again, repeated imaging does not rule out post-dural puncture headache.
If you don’t look at the numbers in detail, too many, but to me the striking results are that the Rcsf out is 10.7, the lumbar pressure at opening is 9 mm of mercury, equaling 12 or 13 cm of water, so this is just normal. All these numbers are normal.
So, to show you in a more simple way in a graph, both the lumbar pressure and the Rcsf out of severely affected patients with post-dural puncture syndrome were normal. No change. No decreased lumbar pressure. No elevated or decreased resistance to CSF outflow. It is striking and unexpected, but these are the numbers. All normal.
So we cannot use CSF testing to rule out or to rule in chronic post-dural puncture headache, or to put it in other words: with this study, and this is the gold standard in infusion testing, we were not able to find any pathological changes in post-dural puncture headache.
What can we learn from this study? It is a single-center small study, but at least with our system, chronic post-dural puncture headache does not seem to be related to a measurable — this is important — a measurable CSF leak, a CSF leak that we can measure with this system. It is not related to low CSF pressure or CSF depletion or to reduced outflow resistance. And again, like in Charlotte’s study, there was no leak visible on imaging.
So it seems to be a problem. But if you look into the literature, there is also already a study from the 1950s and then repeated in 2019 that in PDPH it does not appear that there is a different or decreased opening pressure and no changed pressure-volume index.
So do we really have a CSF leak disorder then? This is the question, and we have to be careful with interpreting this study. And I think there is a wonderful editorial in the study that was published 2025, a couple of months ago, and a wonderful editorial by Jeremy Cutsforth-Gregory, and he nailed it down, so to say.
What we can learn is that we cannot tell from one study that PDPH is not due to active CSF leakage. Probably we can say it’s not gross overt CSF leakage, because we don’t see it on imaging, and we don’t have different CSF dynamic results. So this is not, let’s say, a massive amount of CSF that is leaking, because this we would have seen with our CSF study and with imaging. And probably we can summarize it that despite these patients having symptoms and all the signs, we can currently not identify with our methods that this is normal. So probably our study methods are not sophisticated enough at the moment.
This means that imaging, a normal CSF opening pressure, not just the CSF dynamic studies, just an opening pressure, does not rule out PDPH. And a low Bern score or a normal brain imaging or also a normal spine imaging does not rule out PDPH. And as Jeremy nicely put it in the editorial, we still should continue with blood patching as early as possible.
And so what’s going on there? And there was the first report from Russell MacRobert over a hundred years ago in JAMA that, of course, there should be something going on at the dura when you stick a needle in, and he kind of initiated this, that this is a leaking syndrome, and once the hole in the arachnoid is at the very same spot as the hole in the dura, then we have a CSF leak syndrome and post-dural puncture headache.
We couldn’t really corroborate that, neither on imaging nor on CSF dynamic studies, but there is still something going on. And this is also a comment from Jeremy Cutsforth-Gregory in the editorial, which is very very sophisticated, I think. And probably future work, he says, will demonstrate structural or functional remodeling of the dura that occurs over time, that perpetuates the orthostatic headache in our patients. And I think these are two very important issues or points, that it is a structural thing of the dura, and timing is so important.
There is evidence that very early after post-dural puncture, in the first days, so to say, you clearly find positive imaging, but this is changing over time, and we need to look more closely at what’s going on there to help our patients. And this shifts a little bit the concept of MacRobert from the CSF leaking to more a kind of arachnopathy or duropathy that is evolving over time. Timing is so important.
To elaborate on this, what else do we have? What else can we see? And we have, of course, some surgical findings, since in the most desperate patients, after the MDT decision, we never do this alone. We explore these patients surgically, and we do this minimally invasively in Freiburg over a small incision, and we use this tubular tractus, and we always do these days a three-level approach, because you’re never really sure where the needle hit the dura, where the lumbar puncture was.
And these are some results of our surgical findings, and I think it’s very valid to look at the surgical findings to try to understand the pathophysiology of this disease and what’s going on. And of course, again, we have these arachnoidal blebs you’ve already seen, and I show you some videos from the surgical exploration.
And this is one striking feature. This is what we call neomembranes, and this is never ever the case in a normal spine. And I’ve done many, many, many spine surgeries for lumbar disc herniations and tumors and so on, unrelated to CSF, and not in one instance I found these sticky neomembranes. Only in CSF patients, meaning in SIH patients and in post-dural puncture patients, I do find these membranes.
So there is something going on that we probably do not understand at the moment, but there is a pathological change of the dura. There is the duropathy, so to say. And once these sticky membranes are removed, underneath there is this tiny little bleb that you see on imaging that is clearly oozing out, probably to an extent that we cannot measure with our CSF testing. But there is clear oozing. Whether this suffices for causing symptoms, we do not know, but it’s clearly pathological, and probably it is the same mechanism in these tiny little blebs as we have described in 2016.
My group has shown this in 2016, that in spontaneous intracranial hypotension there’s a dural tear. It’s on a macro level. There’s a huge bleb herniating out. Probably this is arachnoid, and the oozing happens next to the diverticulum, to the dural tear. And probably this is the same on a microscopic scale. So this is just less than 1 millimeter, that there is a kind of a bleb, and the CSF is oozing out next to the bleb, to the still not healed, still open dural tear induced by a spinal needle in that case, in post-dural puncture headache.
And under these membranes, this is just another case. This is the membrane, and under these membranes we found these open tiny holes, a millimeter or so, just at the size of the needle, that we closed. And we also found — again sticky membranes — and several needle holes. So this is one, this is another one, this is another one. And so we have three or four — probably it’s too bright — but we have three or four clear incision needle holes with beveled needles that are persisting in post-dural puncture headache, covered by membranes that we can see on surgery.
A very important finding for the prognosis of our patients are these tiny little ventral leaks. Probably you can see it here. This doesn’t belong here, and this is not on the dorsal side. It’s on the ventral side. Meaning the spinal needle was penetrated through the ventral and through the dorsal aspect of the dura, to the whole thecal sac on the other side. And when you find this in post-dural puncture headache — now you can probably see it more clearly with the red arrow — if you find this, you are kind of have some luck in this poor situation, because the prognosis is way better. In all our patients, we found this ventral leak in post-dural puncture headache.
We opened the dura, this again is sticky neomembranes on the dorsal aspect. We still opened the dura and went all the way through the rootlets to the ventral aspect of the dura, and I show you this is the dorsal aspect. We open the dura, and now we are on the ventral side, and you have this clear, now I’m in with the hook, with the dissector. You have this persisting hole on the other side of the dura, and once we encounter this, we are quite happy because we can suture this easily, and the prognosis is quite grim in PDPH, but all these patients that have a ventral leak are doing very good, very good, so they have a good prognosis.
Again, several arachnoid blebs that we found with corresponding surgical images. We can take care of this during surgery, and there is also another mechanism with these blebs that I would like to show you during surgery, and I think it’s important to look at these surgical findings because we haven’t understood the disease. So probably this gives us some insights that there is a tiny little vein really connected to that bleb, and probably you can see it here. This is a venous vessel, a vein that is sticking to the dura, and you have to cut it sharp to dissect it from the dura. This is not normal. This does not happen normally. And probably this is also one mechanism how the CSF, here I need to cut it and then I can close it. And underneath there is this flap that was under the vein most likely. Here you can see it once the vein was removed, most likely the entry point of the spinal needle.
So this might also explain why CSF testing is negative because the amount of CSF that is, so to say, withdrawn by the body to these tiny little holes is probably too small to be detected by our CSF infusion testing.
This is just more of the same stuff. These are just changes that we can see during surgery. To summarize these findings, so we have clear pathological findings once we explore post-dural puncture headache patients. They have blebs, they have a weeping dura, there can be single or multiple needle holes. So all these attempts to penetrate the dura have been successful and have left some scars on the dura. And from the prognosis point of view, once we find this ventral leak on the ventral surface of the dura, the prognosis after surgery is quite good. Then we find these all kind of sticky membranes, sticky translucent membranes, or sometimes we call it a web pattern because there are a lot of vessels in it, and once we open it, only below these membranes the normal dura appears, sometimes with a hole, not always, sometimes without a hole that we can find. Sometimes it’s more vascularized, sometimes not.
But there’s clearly something going on, and I’ve never found these patterns in non-CSF or non-PDPH patients. So this is something where we need to concentrate on in the future if we want to understand this disease in more detail.
These are numbers from our center in Freiburg. These are real numbers. So in percentages, this is 100%. So in almost all cases you find neomembranes, only in half of them arachnoid blebs and puncture holes, and in only 10% ventral holes. Unfortunately these are with the best prognosis.
And this is very important, that I don’t pretend to have a solution. Even after surgical removal of the neomembrane, not all of our patients are getting better. So surgery for post-dural puncture is still not a solution for everyone, and the success rate is not so good. So only 20%, only 20% are really healed, so to say. They are really clearly getting better. 40% are getting better with still some remaining symptoms, but 20 to 30% do not improve after surgery for post-dural puncture headache, and 5 to 10% even get worse. So this is currently not the solution, and we still need to do this in centers and only based on MDT decisions.
So if you ask me what is PDPH? No. It is imaging negative, it is a CSF study negative. I don’t know the answer. But if you ask me to speculate, I speculate about an arachnopathy, a duropathy, a membranopathy that is probably leading to a soft oozing or a subtle CSF loss syndrome that we cannot see on imaging and that we cannot measure, but is still related to CSF and is still related to CSF loss, probably in a more subtle way, and has a lot to do with arachnoid and duropathy.
It is clearly not a benign disease. The sequelae are severe. It is currently, I think, best managed in specialized centers and in international collaborations, and like in this meeting today, thanks to the Spinal CSF Leak and to the Colorado University and Andrew Callen, we are able to talk about this and probably to find solutions and do better studies.
And to give you my perspective in Freiburg, so if we do surgery in PDPH patients, we only do it after a multidisciplinary treatment team decision, and then the principles are to resect the pathological membranes, to always respect the arachnoid. I think this is key for this disease, to try to restore the arachnoid and to restore the anatomy and rebuild the layers and augment the dura.
And of course there is more work. We are obliged to do imaging at the clinical spectrum, targeted treatment, and also for supportive treatment, and we try to form a register currently now in Freiburg in Europe, and I can only invite patients to participate and colleagues to participate. And of course we need more long-term follow-up and outcome evaluation, and we surely should tackle this.
This was a slide. I took a photograph this year of the European Neurology Conference. These are striking numbers. 1.7 trillion dollars, dollars, euros in health care costs from neurological disorders all over Europe, and 50%, 48% driven by headache disorders. So it’s worthwhile doing this.
And again thanks to my beautiful team in Freiburg, and thanks to you. Thanks to your patients and to the audience and to Andrew and the Spinal CSF Leak Society. Thank you so much.