The following is a transcript of a Q&A session at Spinal CSF Leak: Bridging the Gap 2024. Please note that the transcript been edited for length and clarity to center on the participant questions, whether put forward via online or in-person submission.
Question: I am a physical therapist, and I am here to ask a question of Dr. Callen. If I understood correctly, he was saying that there were typical versus atypical symptom findings that had imaging findings tended to cluster together. Is it possible that some of the atypical findings could be more related to venous outflow disorders? And have you looked at comparing patients with venous outflow disorders with the symptomology that you’re finding?
Answer:
Dr. Callen: Sure. I want to couch some things about the discussion of our paper. It was a very modest sample size; it was 48 patients. And in further subdividing that and looking for patterns, we always have to keep in mind that this is a relatively small sample size. But we did observe some patterns in this sort of imaging and clinical features that we were seeing that seemed to suggest, through statistical tests, that there may be some connection. I’m not an expert on venous outflow disorders, but I know that there’s a lot of interest in that in our field. There was one paper published recently, some co-authors – at least one of them is in the room here – about a potential link between patients with intracranial hypotension and CSF leaks, and potential jugular venous compression as well. But we have not looked at that yet, but I think that further work needs to be done there.
Question: I have a question for anybody on the panel. One of the things that I personally find to be very difficult to wrap my head around is the fact that many people who have epidural leaks and CSF-venous fistulas will not have typical symptoms of intracranial hypotension – or, what we define as typical. And some people who have typical symptoms will have alternate diagnoses. And then there seems to be a lot of ambiguity about what is even a typical symptom?
How are we supposed to understand that? It’s very easy to lapse into nihilism about that and say, “there’s no symptom profile that we can rely on”, or, “there’s no symptom profile that can rule this in or rule this out.” But for people who are out in clinics who are referring patients to see us, they have to have something, right? So, what do you think, as members of the panel – how do you think we ought to approach this issue of sort of variable and not always reliable symptoms?
Answer:
Dr. Jill Rau: That is a tough question. I think we have to listen very carefully to our patients. For those of us who are in a community setting and don’t have easy access locally — I know nobody has easy access because there are so few centers, but it’s even harder for patients who have to travel — we have to be very careful not to send patients – e.g. everybody that we’re like, “oh, well, they haven’t responded to headache meds. We don’t know. Maybe they’re better a little bit when they lay down?” and send everybody.
And so right now, there is no easy answer. I think looking for these markers [of spinal CSF leak] is going to be very, very helpful to have more things that help us cut off here or there. From my perspective, I look at every person a little bit. I listen to the story very carefully. I look for extra signs. If the brain MRI is normal, there are some cutoffs for differences between Chiari and leak, and you look for those. You kind of put that whole picture together, and in your head, you’re like, “this is enough to do it.”
In the meantime, while you’re doing all that, you’re treating the headache, right? You’re trying. Are they responding to any other things? Are you treating the POTS? If your POTS is good now – they’re not getting lightheaded, and they’re still having a lot of orthostatic symptoms – that leans more in the favor of sending [to a leak center].
Right now, we don’t have an answer, and I’m hoping we do in the future. But I think it’s about continually to try everything to weigh them one direction or the other. Once you’ve tried and tried and tried, you send them. It delays diagnosis a lot, but there’s only so many resources we have right now.
Dr. Deborah Friedman: Just to add to that, the whole concept of, “alternate diagnoses”: when I see somebody that I think, based on long conversations with them, and I think in my heart of hearts, yes, they have a leak – I don’t think there’s anything else that causes those symptoms – and then I see the patients go see other providers, and they say, “Well, you just have migraine.”
No, they don’t.
Migraine doesn’t do what leaks do.
“It’s all POTS.” No, it’s not. POTS does not cause orthostatic headaches the same way leaks do. POTS has different types of headaches associated with it and different symptoms.
I just heard a talk by one of my colleagues about this, where she went through the differential diagnosis, and I just stood there, sat there, shaking my head, going, “none of those things sound clinically like a CSF leak does.”
Unfortunately, you just heard from a wonderful neuroradiologist saying that none of our techniques are perfect yet. We can’t always find the leak, and just because we can’t find the leak doesn’t mean it’s not there. So, I guess I just have kind of a different attitude about this. No, there is not an easy answer, obviously. You’ve seen some of my patients, and you know that sometimes it’s just really tough. But my general philosophy is that I don’t give up. Maybe we just take a break, and we’ll re-image at a later time when the technology has gotten better, or maybe just the time is right and their fistula opens up.
I think it’s harmful to a patient to give them an alternate diagnosis that has really no basis in medical reality.
Dr. Ajay Madhavan: Just one real quick comment: one thing I found particularly helpful in those patients – Peter too, and this might be something you taught me along the line – is we get a lot of referral patients. I don’t always have all their imaging, and many times when we get their imaging, and you look back at one of their older brain MRIs, they have a little bit of brain sag or dural enhancement, and it’s gone away. I just have so many patients like that, and I wonder – how many fall through the cracks where we don’t get all their imaging? That’s not to say that that’s the only criteria we should use to pursue advanced myelography, but it is helpful sometimes for me.
Question: Question about radiation dose – I don’t think we talk about it enough. I’ll give a sort of quick patient story that I have in order to ask this question. I have a young patient – prior Division One athlete, getting married, can’t do anything, is in bed. Has had a myelogram, has gone to Duke, has gone to Cedars, is back now, and I’m supposed to myelogram her next week. I am concerned about her radiation doses. I only see what she gets at Georgetown, but these patients are going other places, and we don’t necessarily know how much dose they’re getting. Then, you know, five, ten years down the road, what are we going to be dealing with? So, how are you counseling these patients, if you are at all, and what should we be telling the patients?
Answer:
Dr. Lalani Carlton Jones: I guess I’ll try and answer that. So, I think this is a really valid point, and I don’t think enough of us are talking about the fact that these are high-dose examinations, particularly CT myelography, particularly if you’re doing multiple phases and runs. As practitioners, we have a duty to keep that dose low. So, I mentioned some of these things that we do, where you should be using your non-radiation-heavy imaging to really guide you.
I don’t think that any of us should be surprised at what kind of leak we find at myelography. We should be trying to limit the range that we’re scanning and the number of runs to what is actually necessary and practical. I think sometimes it’s difficult if patients have been to other centers and they’ve had lots of dose-heavy procedures, but we can only do what we can do as practitioners. And don’t do exactly the same – do your technique, but also modify it based on the information that we’re given. And I think, obviously, with younger patients, that’s something we particularly have to be concerned about. I welcome what other neuroradiologists are doing, but there are definitely ways that you can try and reduce dose. We’re working on ways where we reduce the kV and things like that to reduce dose as well. I will often say to the patient doing a CT – “This is a radiation dose examination.” Sometimes I will say, “These are the kinds of doses that we get.” The thing is, it is spread over a large area. We don’t have good data long-term for radiation dose anyway, and maybe more of this will come to light. I think we have to do what we know now, which is to just keep the dose as low as practically possible. That is the whole principle – as low as is reasonably achievable to achieve the diagnosis. Because if you just limit the exam based on that and then don’t achieve the diagnosis, then what was the point at all?
Question: My husband’s a leaker, and he’s gone to a lot of your centers. Within the six-month period of reviewing his imaging, each time he’s told to send all his images — which, for one, as a patient, he can’t do that. There’s got to be a simpler way that [patients] can get the images to each of you, because I’m doing it all. I know a lot of leaker people that I know that cannot do it themselves. So, they won’t even seek treatment because they can’t do the imaging, or fill out the forms.
The other question is: if he has an image done within a certain period, we’ve noticed that even though we send them, they’ve never looked at the prior [images], even if they’re within the six-month period. Why is it that we send them, but then [doctors] don’t look at the previous images, even though sometimes with a second evaluation, they can see something on the images?
Answer:
Dr. Lalani Carlton Jones: I can’t speak for other operators, but can speak for myself. If I see that patients have had a CT myelogram, I want to look at that previous imaging because often that can give us an area that we can focus on. Sometimes it’s been missed, and so we can maybe demonstrate that better, or maybe we don’t have to do anything at all. So, I would always say that if it’s available for review, you should do that. But I don’t know what other centers’ practice is. I don’t know how easy it is to get imaging transferred around the States. In England, it’s also very difficult.
Question: How much communication occurs between the major leak centers?
Answer:
Dr. Linda Grey: First of all, when you look at the imaging de novo, you want to get your own idea about what the imaging is. Because I don’t want to know what somebody else thought originally, right? I want to look at it first, and then if I have some kind of a question, I may talk to that person. But sometimes, if they’ve already missed it, you’re not going to be coming to me because they saw it. Do you see what I’m saying?
Question (continued): We still are seeking [care]. So, my problem is, now he’s getting extra dosage of radiation.
Dr. Linda Grey: Okay, but I did look at that study. Do you see what I mean? I look at that study before we go on. So, we look at that, and if [a leak is] there, then, you know, we may confirm it or something like that. But we’re going to look at the study before we’re going to engage in another study. Does that make sense? Does that answer your question?
Dr. Samantha Petrucci: We try our best to. I know, at least here, if we ask for [the images], we’re reviewing all of it.
Dr. Jill Rau: One of my patients texted me, who’s on virtual, and said there is a very good app that she’s used to help send her imaging around that I thought maybe everybody – or she thought everybody – would be interested in. It’s called My Links, and apparently, it’s a place to collect all the links in your own imaging and be able to share it.
Moderator: I wanted to really quickly address for our virtual attendees – many of our excellent questions have already been addressed by our morning session. So, we had questions about – can a normal, or high opening pressure measurement rule out a spinal CSF leak diagnosis? We know that’s not true – that many of our leakers have normal or high.
We talked about some of the grouping of typical and atypical symptoms. We talked about optimal MRI protocols. These are all questions that were pre-submitted. We talked about potential internal jugular venous compression.
Question: One thing that we haven’t talked about yet for our expert panelists: have there been any proven cases of intermittent leaks? And if so, are there special imaging considerations made for this type of leak?
Answer:
Dr. Andrew Callen: I don’t know if I have a perfect answer to this question, but I think Dr. Madhavan has shown some great examples where we are unable to prove the presence of a leak or fistula on a particular exam. Then we bring the patient back, try again very slightly differently, and then it’s there.
So, it’s a reasonable sort of assumption that if we have to do something different to make the leak show itself, whether it’s position them different, pressurize them or not pressurize them, get the timing differently — then potentially that could reflect the underlying pathophysiology.
If they could leak more in a particular way or not: I think it’s very hard to prove it because there are so many different variables at play at any given examination. Is it simply just a result of the test, or is that a reflection of what’s going on underneath? But I think that’s the best answer, at least that I have.
Question: Do you think that MR myelography adds additional useful evaluation for these or possible slow leaks that aren’t easily visualized on DSM or CTM?
Answer:
Dr. Andrew Callen: We have some [leaks] that we’ve not been able to see on CTM that we have found on MRM. But it’s a minority. We have a handful of those cases, so I don’t know if that’s the same thing as an intermittent leak. I get that question from patients sometimes – like, is it happening sporadically, or is it slow and constant? I don’t really know the difference between these, but yeah.
Dr. Ajay Madhavan: Just one thing, I guess, to tie together the last couple of comments. So, one thing I tell my patients who I think may have intermittent types of fistula or leaks is: if I start out with a photon-CT and we’re trying to minimize radiation going forward, then oftentimes I’ll just do a DSM after that to reduce dose if I know it’s somebody who may need multiple studies. There’s no great science behind that, but that’s just kind of my thinking to try to do the best thing for them and find the leak at the same time.
Question: For academic purpose, if so many myelograms are done, would you feel it useful to record all the pressure, just for us to see what the field is doing in terms of understanding what the pressure is like? Because many patients say or are told, “This pressure is low for you,” or, “This pressure is high for you.” Do you think, or are you aware of, any study being done in that regard? Since you do myelograms, you do lumbar puncture anyway.
Answer:
Dr. Linda Grey: I mean, we do. We get pressures on all of our patients when we’re doing a myelogram, so we have pressures on everybody. The only time we would not have a pressure is if we’ve already maybe done a myelogram, and we’re doing a prone myelogram for a really fast scan, in which case a lumbar puncture pressure is not going to be accurate. But all of our patients really get a pressure measurement, right?
Question (continued): But for academic purposes, would that be useful to collect all this data?
Answer:
Dr. Linda Grey: Ah, you mean like in a sort of multicenter trial? Yeah, it could be. I don’t know.
Question: Regarding the intermittent leaking: has there been any collection around patient-reported symptoms? How quickly should a patient push to come in for diagnosis if they are experiencing symptoms that might indicate an escalation in their leak? Is testing going to be more accurate if they can get a quicker set of diagnostics? So, if I’m having these symptoms, what test should I try to get, and how quickly, in order to pick up on that changing scenario?
Answer:
Dr. Ajay Madhavan: I guess I don’t know the right answer to that either. But I think the two patients I showed, both of them were relatively the same degree of symptoms between the studies. So, at least anecdotally, it doesn’t always bear out that symptoms portend a higher chance of finding the fistula. But I’ve also had cases where it does. I think it’s a great question because it’s something that’s probably a ripe area of active research that will really help patients if we can find some sort of predictor of when we should do your myelogram.
Dr. Jill Rau: I’ll just say, unfortunately, very little progress is quick in this. For individual patients where things are getting really worse – if they’re really worse, we’ll repeat imaging in a community center to look for venous thromboses or subdural hemorrhages or things that, at that point, would be dangerous in a different way than the leak. But when you’re at a place that’s not a CSF specialty center, getting them there faster is not very likely. So, it’s about checking to make sure there’s nothing that we need to temporize in the meantime and then trying to just reassure your patient that we will get you there, and they will do their best for you.
Dr. Deborah Friedman: The dural enhancement of the brain MRI tends to go away over time, so at least that particular sign on the imaging might be helpful if people got in earlier.
Moderator: Ok, well thank you very much for your attention this morning and for the lively discussion. We will break for lunch and come back at 1pm. Thank you.