Dr. Geoffrey Parker at the 2023 Cedars-Sinai Intracranial Hypotension Conference
Dr. Geoffrey Parker, of Macquarie University Hospital in Australia, presented this talk on interventional treatments and cautions for RIH at the 2023 Cedars-Sinai Intracranial Hypotension Conference on July 9, 2023. The conference was hosted by Cedars-Sinai with generous support from the Spinal CSF Leak Foundation in Kohala Coast, Hawaii.
Transcript
[00:00:12] Thank you. Thank you very much. I did have to ask Wouter what he wanted me to address in this talk, because I didn’t think that there was much here for the interventional neuroradiologist, but he means interventional in a broader sense. So once I understood that, I had a bit of an idea where to go. And Peter has already mentioned his paper from the AJNR in 2014, which put together an opinion that this problem really was quite widespread and it had only been described in a handful of papers in the literature prior to that. And he said that it’s actually not uncommon.
[00:00:53] And we’ve just heard some numbers that show that. And he said that, and this is a problem that we’ve run into, the primary clinical manifestation is headache, which may be associated with nausea, vomiting, and blurred vision. But because the patients with SIH also have headache as their primary complaint, and because experience is limited with these patients at many centers, it’s pretty easy to make the mistake and think that they have refractory SIH.
[00:01:28] And it’s been our experience in Sydney that some patients will swear that they have high pressure or low pressure and they cannot tell. Some of them cannot tell. And it’s not until you do an ICP monitor or just a lumbar puncture that you’ll find that a patient who says I’ve done, you know, terrible low pressure at the moment, that their pressure is, you know, 33 or something like that. And as a consequence, if you treat someone with RIH for SIH, you can make them worse. So, therefore, it’s very important to keep this in mind.
[00:02:04] So, Wouter’s group’s paper in 2019 has also been mentioned because it was very important, because they prospectively surveyed 113 patients undergoing treatment for SIH and they found that 31 developed RIH, with RIH being defined as as those three things, but principally resolution of a headache with acetazolamide. So this is not an uncommon problem, and as we’ve already been told, the patients, all the patients had an MRV beforehand, and they found that 14 patients with RIH had basically normal MRVs, and 24 percent had a narrowing of both sinuses, but mainly on one side. 44 percent had grade two narrowing.
[00:03:02] And I haven’t got the, I haven’t got the score of four on here. There were no patients with a score of four, but 67 percent had a narrowing width here and here. So, venous sinus narrowing is common, and all of those patients with RIH had oral acetazolamide; nine didn’t tolerate acetazolamide and diuretics or topiramate was prescribed; and overall, rebound high pressure headaches resolved with medical treatment within six weeks in 25 of 31, and within three months in a further four patients. So that’s 29 of 31, and one had to undergo a VP shunt and one could not be weaned off acetazolamide at 15 months.
[00:03:46] So yes, it’s a very common problem. Occurs in about a quarter of patients who are treated for SIH. It’s characterized by, usually by a reverse orthostatic headache, and you don’t need to do an LP to diagnose it. And transverse sinus stenosis is a risk factor. So, one of the questions is why does RIH occur? And well, it could be because the patient has a pre-existing high-pressure state. And it’s well known that patients with, as Deborah said, patients with high intracranial pressure are well known to develop cranial CSF leaks, erosion of the skull base, and formation of an abnormal communication between the subarachnoid space and the paranasal sinuses.
[00:04:33] So, what’s the likelihood of a pre existing high CSF pressure state being a risk factor for developing a spontaneous CSF leak? Well, we’ve seen this in a number of patients you know, typically a patient with a typical IIH phenotype who develops leaks from four or five nerve roots at the one time. So it’s, it’s most commonly found in patients with type 1B leaks and also in those without a connective tissue disorder, which must be a minority because we know that the majority have some form of connective tissue disorder, as we heard yesterday.
[00:05:14] And this is Deborah’s slide to answer the questions of, was IIH the original problem? Do they have the typical phenotype? Have they had treatment for acne, for example? Do they have undiagnosed sleep apnea, which I think is very important? Has there been a history of a skull-based leak? Do they have pulsatile tinnitus? So question number one is do they have an underlying high pressure state? Question number two is, is there a physiological increase in CSF production due to a CSF leak? We, we know that the volume of CSF is 125 to 150 mLs in the subarachnoid space, 25 mLs in the ventricular system, and we normally make about 500 mLs per day. So CSF is replaced four times a day. Now, I’m not aware that it’s ever been proven in one of our CSF leak type patients that the production of CSF is increased, but there are some papers in the literature.
[00:06:19] For example, this paper from the Croatian medical journal. They had a child with Crouzon syndrome, and they had to put in VP shunts, and for a series of reasons, thE-shunts had to be externalised. So they were able to measure the CSF production per day, and it got to 1700 mLs per day in this child. And they eventually had to do, this sort of supports what Marcus said, they eventually had to do endoscopic burning of the choroid plexus in order to get the CSF production down to about 700 mLs a day.
[00:06:57] So is, the next question is, is there a rise in CSF pressure, and does this just take time to adjust? And I think that, you know, that’s present in many patients. The third question is, do patients with treated SIH develop RIH because the compliance of their CSF space is reduced? Many of you will be familiar with the two balloon experiment, which was described, some of the older people in the audience will remember Professor Julius Sumner Miller, and this was actually his discovery, which he reported in the American Journal of Physics in the mid 50s. So if you have two balloons connected through a pipe and you open the pipe between the two balloons, rather surprisingly, or paradoxically, what happens is that the smaller balloon gets smaller and the larger balloon gets larger.
[00:07:55] And that’s because the surface tension in the smaller balloon is greater because the rubber is thicker. And so, here’s a graph of pressure versus the radius of the balloon. So, you’ll know this yourselves, if you’re trying to blow up a balloon for a child’s party the hardest part of the balloon to blow up is the first part. And after that, the balloon becomes easier to blow up. So then if, let’s say, let’s say the CSF space is like this balloon here, and its volume decreases because of a leak. Does that therefore mean that the compliance of the CSF space is naturally decreased, and therefore adding a certain amount of CSF leads to a larger increase in pressure than it would if the CSF space was of normal volume? I think it’s a very interesting concept. But I don’t, I’m not aware that it’s been worked up in any greater detail than that.
[00:08:57] So what do you do about high pressure after leak repair? Well, medical treatment first, lumbar puncture for opening pressure measurement, CSF drainage. You could put in a venous sinus stent if If there’s a suitable lesion. You could correct jugular venous compression, if that is the case. And I’m going to mention a strange device called the E-shunt in a minute. And then VP shunting would be, that should be the last resort.
[00:09:26] So, a venous sinus stenting, I think it would be ideal if that condition were diagnosed and treated before the SIH was treated. So in other words, you have a patient with SIH, you find that they have venous sinus stenosis and you say, we need to treat your underlying high pressure state so that your CSF leak is more likely to heal. More likely to heal and more likely to so-called “self close” or cease spontaneously. If it’s necessary, go ahead to venogram manometry, show the stenosis, put them on dual anti platelets as we discussed, and treat with a stent.
[00:10:04] If on the other hand, you’re able to show that they have jugular venous compression, here’s a patient with bilateral jugular venous compression, so the, the transverse sinus is abnormal, the jugular vein is narrowed. You can release the jugular venous compression, and we’ve tried to do this just with styloidectomy, and we’ve had mixed results. We found that a three-stage operation or a three-component operation is the best thing by far. And so you need to resect the styloid, that needs to be done by an external styloidectomy, because you can’t, if you do it in with an internal transpharyngeal styloidectomy, you can’t get high enough. There is some fascia around the internal jugular vein which needs to be released. And often the lateral mass of C1 needs to be partially resected. And if you do that, you will see that the jugular vein just expands before your eyes. This particular patient said that she felt better the day afterwards and has done very well.
[00:11:14] We’re a little bit reluctant to put stents into the internal jugular vein now. We’ve had one patient who, you can just see here, you can just see running across there, the spinal accessory nerve. We’ve had one patient who complained of a lot of shoulder, ipsilateral shoulder and arm pain. And there are studies in the literature that suggest that there are some sensory fibers in the accessory nerve, and we wonder whether we might have traumatized the accessory nerve by blowing up the stent to overcome a stenosis.
[00:11:48] So we, we think that’s potentially a good treatment, but at the moment, we are trying the surgical approach. The E-shunt is another device that’s just been described. Pedro Lylyk in Argentina has done the first case in man. And so what happens is that, via an interventional approach, you put a guiding catheter into the internal jugular vein. You go up into the inferior petrosal sinus. And this is actually, this is a non-detachable stent, which is just used as an anchoring device. And you come up here with this little detachable stent device, they call a Malecot, and you poke it through the wall of the inferior petrosal sinus into the subarachnoid space, and you then, you then release it. And that is the device that needs to go where that green arrow is. There’s the spinal accessory nerve there. So you have to be quite careful not to damage things. I haven’t done one of these yet or even considered doing one, but it has been reported. And then the last interventional treatment would be VP shunting. So that’s all I have. Thanks so much.