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Thank you. Thank you so much. It’s a real pleasure and honor to be here. Thank you for organizing and inviting me. I have no relevant disclosures for this topic.
Chronic PDPH is not really addressed in the national classification of headache disorders. This was a very impressive talk by Julie. But still, what’s going on after 14 days, or if a post-dural puncture headache is not resolving upon the blood patch – at least in Europe, or in Germany, it’s in the hands of the neurologists and the general practitioners. “This cannot be. It’s a different disease. You’re suffering from something else.” Or, even after labor, you have other problems. This is really the daily situation we are facing.
Post-dural puncture headache is not SIH, despite the symptomatology being quite similar. I think the etiology is different, and we do not really understand what’s going on in post-dural puncture headache. It’s a tough topic, SIH, but dealing with post-dural puncture headache patients is a real challenge.
The symptomatology is quite similar. I don’t touch on all these symptoms, but mostly, most of the patients have orthostatic headaches. But a lot have cognitive symptoms, brain fog – as you put it here in the US – and also depression-like symptoms, anxiety, and so forth.
It’s not a benign disease. We heard in the last talk, very impressively, what it means in daily life. But still, patients are confronted with, “Come on, it’s just a headache,” or, “Have a rest, drink, and it will go over.” So, this is definitely not the case.
But there are no good data out. This is just a very referral-biased evaluation of some patients we evaluated two years ago in Freiburg. Up to then, we had like 60 patients. Just look at the numbers. These are the average – 381 days of sick leave, these patients had consulted a lot of doctors, were even institutionalized in several hospitals, and had on average 31 days in acute hospital care because of this so-called benign disorder.
There is a very good cross-sectional survey using social media by Ali Kapan and his group in Vienna. Just to give you some numbers out of his publication, patients in this group were only able to work full-time in their same job 12%, and parents were only able to take care of their newborn in 12% of the cases for one day.
Now, coming to our neurosurgical findings in this patient group, 2/3 are patients after a diagnostic lumbar puncture, and 1/3 are patients after labor peridural anesthesia – spinal anesthesia. All of them had at least three epidural blood patches before they came to our place.
It was very nicely shown how the principles of surgery by Peter Lennarson how this works. We use a minimally invasive surgical approach for the lumbar spine as well. We can cover with one inch skin incision all three levels that we are aiming to explore.
This is thanks to my great team in Freiburg. A lot of people are taking care of these patients, especially Katharina Wolf, Amir El Rahal, Niklas Lützen – brilliant work. He delivers us the pictures, Florian Volz, and also many other specialties, and even our friends all over the world working with us.
Giving you some examples now. You already heard of this teeny tiny little bleb here. This is a sign of probably where the leak is. We are not sure really. To see how this looks during surgery is probably a completely different picture than in spontaneous intracranial hypotension. Again, we use this tubular 20 mm access, and then you see these huge membranes. They’re very sticky and very vascularized to the dura. It’s a new layer. It’s clearly not there if you do spine surgery. After you remove this and you see this tiny little bleb at the very spot on the MRI and you see this oozing out of CSF that is washing away the blood. We’re calling this the “Weeping Dura”. And there is probably the same mechanism that the CSF exits at the edge of the dura – of this dural cut next to the arachnoid outpouching.
Then this is the stills of it. You see this sticky membrane with a lot of vessels in it. Maybe this is a clue of another pathophysiologic mechanism – that the vessels are transporting the CSF away from the leak, and this is the blood just gathering around this bleb. And the CSF is just this little river here flowing away from this point. If you explore it over several levels, usually it’s only over one or two vertebral levels where these neomembranes form. They don’t form all along the spinal axis.
Another case – I think what might be important, you can clearly see the bleb here. And what might be important is that you not just cover it – you need to reconstruct the dura. And the way we do this is we put in a little sealant that pushes the bleb inside the dura propria, and then after that, in this case, we can suture it. And we suture even another layer of substitute material on top of it.
So, we have repositioning of the arachnoid bleb and then a sandwich patch that we suture to the dura in this instance. So, the pathophysiology, as I suppose, is similar to the diverticulum. The CSF – we have published already in 2016 – oozes out next to the diverticulum, not through the diverticulum. It looks like it might be the same in these tiny little micro-blebs, that there is an arachnoid outpouching, and the arachnoid prevents the dura from healing. At least, this is my theory, and the CSF is oozing out next to the bleb.
Then, what you also can do – if we have, for instance, several leaks – we can do combined techniques and also do a collar and a 360 patch around. You see here two needle holes after removing of the membranes. You see two needle holes, one up here and one there – and both are oozing. What we did here is, additionally to repositioning the bleb and closing it, sealing a dural substitute all around the 360° of the thecal sac. Then we repositioned, reduced the arachnoid bleb. These are AnastoClips®. I was originally trained as a vascular surgeon, so I think sometimes the AnastoClips® work quite well. There’s no additional hole from the suturing, and then we handle the 360 column. When it’s tight, I apply an angled aneurysm clip to it. It really gives an additional sealant around the 360 surface of the thecal sac.
Very interestingly, you saw cases of ventral dural puncture – double puncture holes. Curiously, I think in these cases, there is almost always a SLEC associated with it – at least a tiny little SLEC. So, the dorsal puncture holes are imaging-negative. Sometimes you see this tiny bleb. But the ventral holes are curiously most often open, and you can even see the outflow of contrast material.
We also heard about, from any of these, the dinosaur tail sign you need to look at. These are probably the most significant signs in imaging – either very tiny or a little bit larger blebs. This is a case – we identified four blebs. If you can see, this is a myelogram. There’s one bleb, the second bleb, a very tiny third bleb, and a fourth bleb. They were all real blebs and arachnoid outpouching at the spaces that Niklas has shown us here.
Long-term chronic PDPH – I’m speaking about 5, 10, 20 years after dural puncture – so it’s getting more and more complex. You see, yeah, some membranes probably in the SLEC in the bleb. It’s a large bleb, and this is how it looks during surgery. Again, the access is minimally invasive, and you see a lot of neomembranes. There is no CSF oozing out – only when I open the neomembrane and remove the sticky membrane. You see how the CSF is oozing out, and this is 10 years after lumbar puncture. This is now very interesting. This is very sticky, and when I remove the sticky membrane, suddenly the puncture hole comes into field of view. It looks like, really, it still has the shape of a sharp puncture needle, and there – CSF is oozing out like a jet then. And we do not know whether this happens and is oozing beneath the membrane, whether the membrane kind of sucks out – sucks off the CSF. And then the principle is, again, the same: reduce the arachnoid, try to reconstruct the dura, and only then suture it. Just don’t cover it simply with some material.
This is 20 years after giving birth with a PDA during labor – 20 years after. And very interesting finding. Again, an arachnoid bleb, a large one, not a tiny one, and there were strangulated fascicles and was referred to us because we cannot operate on this. It would be paraplegia afterwards because the nerve roots are out, and you here, you see the dura. But this is not the dura – the neodura in chronic cases really resembles the dura. Open this false membrane, and only then you enter the site of pathology, and then you see there is a space filled with CSF, and then you have the dura propria underneath this neomembrane – you have the real dura, and you see the strangulated fascicles popping out of this puncture hole 20 years after labor.
And then it’s rather easy, but still, free the edges of the dura from the arachnoid. I strongly believe that the arachnoid is preventing the hole from healing on its own. We need to free the edges of the dura, reduce the fascicle, reposition them, and then you can suture it. I n this case, even in a double-layer fashion because you have the neomembrane that helps you close it in this instance here.
This was already reported over 100 years ago – that probably the arachnoid is the key player here, whether the arachnoid hole is really over the dura or is popping out. I think this is the key mechanism in chronic post-dural puncture. And again, we published this in 2016 and in all our reviews in, again 2023 – that the arachnoid is probably key, and I’m happy that people from Mayo Clinic also published this now, 2024. It’s really important that not the tick is leaking – it’s next to the tick, in between the dura and the diverticulum, is the CSF oozing out. I suspect it’s the same in post-dural puncture. I cannot prove this yet. Be aware of this very sticky, vascularized neomembrane that is around it. And these neomembranes are key for my understanding for SIH and for chronic post-dural puncture. You need to be aware of these membranes that prevent – unless you do it like Mamlouk – Mamlouk has shown us – really with the needles into this SLEC-space and compressing it. These membranes prevent healing, and I think it’s the same in post-dural puncture. You have to not have this outer membrane, but the inner membrane is very sticky to the dura and has a lot of vessels.
Maybe these vessels – as Vinay has shown us – clearly also use ICG in these cases in the future to see whether there is a drainage pattern that we can detect. I think the microanatomy we see under the surgical microscope probably gives us some keys to understanding of this disease because it’s not a low-pressure state. There is no really intracranial hypotension in PDPH as well, and this was shown in 2019. We have done a series now where we did lumbar infusion testing in patients with post-dural puncture headache, and the rCSF out is not changed – all the other parameters are not changed. So, it’s not an acute intracranial low-pressure state.
So, what is it then? I really can speculate after our experience and the surgical findings. It’s a kind of leaking syndrome – probably a slow leak, an oozing, or a weeping as we have called it, or even a combination of all these three mechanisms, or also an increased absorption of CSF by these neomembranes that are very vascularized and sticky.
It’s very vague only to give you some facts – at least not only vague theories. What I do in surgery for PDPH is resect the pathology, resect these neomembranes. They don’t belong. They are sticky. They are, I think, part of the pathology. I restore the anatomy – really reduce the bleb, rebuild it in layers. Don’t just cover it with something sticky. Rebuild the dura in layers, augment the dura, and always respect the arachnoid. I think the arachnoid is the key element in CSF leaking in the dura – in the spinal dura.
To look into the future, we’re just establishing a PDPH program in Freiburg. I think we need to be more systematic and do systematic imaging with the protocol, and all the decisions we do should be done by a CSF board because it’s not non-invasive doing surgery. So all decisions should be based in a multi-disciplinary team. And once we suggest proceeding with surgery, we even ask our patients now – please let us do lumbar infusion testing and Gallium CSF PETs and dynamic studies at the very place we will perform surgery anyway – so that you don’t have to be afraid of an additional dural puncture. But this needs to be a shared decision-making process on whether we do this or not. And key, of course, is to assess the clinical spectrum with numbers – with headache numbers, with PDPH inventory – and follow the patients over a long time. So, it’s really mandatory not to tell them when they are good for the next four weeks, but they need to be in a long-term program.
So, thank you very much for your attention.