Dr. Jürgen Beck at the 2023 Cedars-Sinai Intracranial Hypotension Conference
Dr. Jürgen Beck, Director, Department of Neurosurgery, University of Freiburg, Germany, presented this talk titled “Subdural Hematomas in SIH: Incidence and Management” at the 2023 Cedars-Sinai Intracranial Hypotension Conference on July 8, 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] This time, I’m happy to talk about subdural hematomas in SIH, about the incidence and the management of subdural hematomas. It’s one of the most common neurosurgical procedure we do, the burr hole craniotomy or twist drill craniostomy for subdural hematomas. And we just happen to have a study from Switzerland, and the beauty in Switzerland [is], it’s a small country. And there are only, I think, 14 training centers with neurosurgical residents and almost all emergency cases go to these centers. So we have a kind of a population-based study about the incidence of chronic subdural hematomas.
[00:00:56] And this is just in press, this paper, and the overall incidence is around 10 per 100,000, but it’s clearly a disease of the aging population, so over age 70 we already have 58 per 100,000 and over 80 we have 64 per 100,000. And the typical recurrence rate, which is a very interesting number, because it’s it differs from study to study, but this is a population-based study, so it’s, 20 percent is the recurrence rate, which I think is quite high.
[00:01:26] And if you look at the age groups, so I think in the next two decades, this population group will double in Europe and in the US and in Australia. So this will continue to be a major problem concerning the numbers in neurosurgery. And a couple of days or one or two weeks ago, a very interesting paper was published in the New England Journal of Medicine, it’s about burr-hole drainage in chronic subdural hematoma, and they randomized it against no surgical procedure. It was not burr-hole surgery plus dexa—so, steroids—it was burr-hole versus. And interestingly, two years ago, Peter Hutchinson from Cambridge published already a study, also in the New England Journal of Medicine, that dexa medicine is not helping, is not good in chronic subdural hematoma. We have another study, and again, they were not randomizing relief of the symptomatic hematoma plus dexa versus no, but they were just randomizing surgery versus no surgery at all and giving a course of steroids. And the trial was stopped prematurely and was still highly significant. And it was, of course, worse for the non-surgical group. So the main bottom line is from this trial, if the patient has a symptomatic subdural hematoma with a mass effect, it needs to be taken out, it needs to be relieved. And this was highly significant, even if the trial was prematurely stopped, and even over 50 percent of patients in the dexa group had still. surgery for the chronic subdural hematoma. So I think we have really good evidence that a symptomatic hematoma needs to be relieved.
[00:03:11] This is important for the following studies and for all the MMA trials that are about to come. But the topic was, is a spinal leak the cause of a chronic subdural hematoma? And we did in Bern back then a study because we had a case of a young patient—it’s the first risk factor —who almost died and he had a chronic subdural, and there was a recurrence and there was a recurrence and he was on the ICU, and we had a hard time, and we couldn’t bear having a young patient dying from a chronic subdural hematoma. Until we realized that —this, of course, now we know it—there was an ongoing spinal CSF leak. It took some time. And this was just the initiation that maybe this is the cause for chronic subdurals in young patients in many more patients that we think, and we didn’t know at the time. It was, I think the case was 2008. We didn’t know at the time about type one, type two, type three leaks, they weren’t even found in the literature yet, Wouter hadn’t published his cases in 2008, so it was just the impression that there must be some oozing out of the dura in cases of recurrence of dural hematomas in young patients.
[00:04:24] And then we did the study, and all the, of course had cranial imaging CTs or MRIs for the diagnosis of the chronic subdural hematoma, and then we did spinal imaging. And look, at that time we did just an MRI of the complete spinal axis and we did in all cases intrathecal gadolinium. We published this later in another series that in our hands in Bern at the time, intrathecal gadolinium did not add anything specific for finding leaks in a spinal MRI. Then we did dynamic myelo, and even post myelo CT at two time points: immediately post myelo, and four hours after the myelogram, with the impression that we need to detect subtle small leaks.
[00:05:09] So this was the protocol. It was done over one and a half years starting [in] 2009. And for a mid-sized European neurosurgical center as Bern is, we had 220 subdurals over 18 months, and roughly 10 percent were younger than 60 and were included in the analysis, so 27 patients, and with a very low incidence of trauma on history taking. And we found these, at that time, curious findings: epidural fluids in the spine and this diverticular spinal meningeal cysts and clear leaking of CSF. And the most interesting finding was that every fourth patient had a CSF leak. So it was not a CSF, it was not a SIH group, it was the typical patient group of neurosurgical emergency department where patients with chronic subdurals come in, and if they were younger than 60, every fourth of these patients had a proven CSF leak. And since we didn’t know at the time about type one, type two, type three lesions, we kind of tried to classify the findings, as I will show you later, but it was striking that only 40 percent with a proved CSF leak had a history of head trauma versus almost 80% without a proven leak that had a history of head trauma, and the recurrence rate was almost 40%. So this is really young age, and a high recurrence rate is a risk factor of finding a CSF leak and vice versa. All patients with multiple recurrences had a proven CSF leak and the presence of bilateral subdural hematomas.
[00:06:54] I think this, these are facts that we now all know, but at the time we didn’t. So the presence of bilateral chronic subdural hematoma were clearly related to a CSF leak. And since we didn’t have the classification and the etiologies of the leak, we tried to classify how likely it is to have a CSF leak at that time. And we made the six categories and even discriminated plain SLEC, so extra-thecal fluid detection was not sufficient for proof of a CSF leak at the time, we needed to see direct visualization of contrast from the intrathecal space. And still we thought at the time that spinal meningeal cysts are probably prone or form or a kind of CSF leak. Even at the time.
[00:07:47] There is only one other series I’m aware of that is looking at the incidence of spinal CSF leakage via CT myelogram in patients with non traumatic intracranial subdural hematoma. This is a special subset of patients. It was done in a very nice study in Korea for non-traumatic intracranial subdural hematoma.
[00:08:07] You see images with spinal CSF leaking here, and it was a retrospective study done over seven years, and one inclusion criteria was that patients didn’t have a history of trauma, which is usually the case in chronic subdurals, and the absence of coagulopathy, and probably, and this might explain the high numbers, this rather is a patient group that probably we would summarize as a patient group with SIH these days.
[00:08:37] And because one inclusion criteria was just a suspicion of the neurosurgeon. So a CT myelography was ordered by the neurosurgeon in all cases without an explainable cause for the subdural hematoma. And the results were striking: 80%. 80 percent in this group had a CSF leak and there was not as a sharp age threshold as in our study. So also the patients 70 and older had a very high incidence of a leak, 60%, 60%. And you need to consider. This was done by CT myelography, and no CSF venous fistula was detected or looked for, so probably with other studies, the incidence would close, would approach 100%.
[00:09:29] Yeah, these are some examples from the study. You see bilateral subdural hematoma, and you clearly can see here, in this case, an anterior SLEC, so to say. Blood patching was performed for all of these patients and 31 of the 60 underwent surgical removal of the hematoma. There was a high incidence of recurrence, but all showed complete resolution following one or two epidural blood patching procedures.
[00:10:00] And 10 patients developed a recurrence after a single procedure, and repeated blood patching was done up to three times. And again the neurosurgeons were quite convinced that these patients have leaks, so they even ordered blood patching with a negative CT myelogram.
[00:10:19] So this probably explains the very high incidence. And even in this series, two thirds of the patients with the hematomas required surgery for the hematomas. And of course, if the incidence is as high as this, a blood patch is probably the next thing that comes to your mind that we can do or should do for this patient group, non targeted blood patching.
[00:10:44] And there’s another procedure that comes to your mind probably, which is MMA embolization. You see this blush of vessels in the lateral view and you see it in the AP view and you can inject particles to close the middle meningeal artery, which is shown here, and you can treat patients with chronic subdural hematomas with MMA embolization.
[00:11:07] And more and more reports are being published, a small series of case reports that you even can combine, for instance, CSF venous fistula embolization and middle meningeal artery embolization in one stop shop, so to say.
[00:11:24] Now let’s look at the other perspective, and this is again a Freiburg series now looking the other way around, looking in our SIH cohort, how often we do encounter chronic subdural hematomas.
[00:11:37] And this is a series now of 216 treated, surgically treated or embolized CSF leak patients with leaks and fistulas. 200 surgeries, and 13 embolizations. And a third, 28 percent of these patients had chronic subdural hematomas. And the features of these hematomas differ from the features of hematomas that are not associated with CSF leaks.
[00:12:01] So 90 percent of them, 88 percent of them are bilateral. So again, young age recurrence and now bilaterality is really associated factor of having a CSF leak if you encounter someone with a chronic subdural hematoma. And they are quite small so the median width of the subdural hematomas was five millimeter right side, 4.5, and left side six millimeters or five millimeter, which is smaller than the chronic subdural hematoma we encounter without a CSF leak. So it seems to be a specific patient group. And of these 60 patients with a CSF leak and with a subdural hematoma, only 30 percent had evacuation of the chronic subdural hematoma at any time point before treatment of the leak.
[00:12:47] And it happened mostly in the days before, but some are chronic diseases and they had many days, even a year before treatment of the CSF leak. And probably this is a number which we should publish or we should think about is, at least in our series of these 200 patients and 60 subdural hematomas, no chronic subdural hematoma less than 12 millimeter, to give you a number, needed surgical evacuation.
[00:13:16] So we really have the connection between subdural hematomas and CSF leaks. And to give you one example that these chronic subdurals are not harmless. This is probably a hygroma but on CT you wouldn’t be able to discriminate it for 100%.
[00:13:35] This is a 52 years old female. A teacher, three kids, very well integrated, what was one of the first cases when I started in Freiburg, and the outside neurologists even made the diagnosis of SIH and subdural hematoma. They did one blood patch, and I did one study that showed a large thoracic disc. It’s T9-10 left as a suspected side of the leak.
[00:14:02] And the plan was, that’s fine and let’s do another blood patch in several weeks, or at the latest in three months. And sure, you could consider microsurgical closure of the leak, but it was not planned yet. And she came back with a helicopter with blown pupils and acute worsening, and there was a fresh blood in the chronic subdurals bilaterally, and even which is also typical after evacuation, they recurred as a kind of an epidural hematoma then.
[00:14:31] And if you look at the slices through the brainstem, there was a hemorrhage and bleeding in the brainstem. So it’s not harmless, you should not wait, and the outcome was horrible. She survived, but there was bithalamic infarction and cortical blindness. So, which is a horrible outcome. And to show you what we did, I remember the case very well, since it was one of the first cases, there was the patient I encountered in the ICU.
[00:14:57] And we had, due to the emergency surgery, intercranial pressure monitor in place and the pressure was very low. We immediately did some injection of saline intrathecally, and she opened her eyes. At the moment we injected the saline, she opened her eyes. And then we did surgery for the large thoracic disc, but there, there was no CSF leak.
[00:15:20] It was just, okay, there’s a large disc, let’s do a surgery. And there was no increase in ICP after surgery. Then we did what we should have done before. We did real dynamic studies, identified the leak at the thoracic one, two, where the most are, the ventral leaks. And we did small surgery, typical leak, closed it. And afterwards, of course, the ICP has risen. So very straightforward. The issue was just that the long period of [???] She had the chance to deteriorate suddenly and has this real poor outcome, just as one example.
[00:15:56] So, subdural hematomas in SIH. They are clearly associated with chronic subdural hematomas. The level of evidence is not sufficient to say there is a causal relationship, but I think, of course, there is a causal relationship.
[00:16:10] Risk factors are young age, bilateral subdural hematomas, lack of trauma, and as shown by the case, if suspected, the search for leak should not be delayed, and which is, I think, important is that now we have an additional treatment target, okay? We should not switch for treating the leak only. I mean, MMA is fine. We do it too. But in a symptomatic subdural hematoma, as was nicely shown in the study from the Netherlands published in the New England Journal last week, if it’s a symptomatic subdural hematoma, take it out. And then you can additionally treat the second target to CSF leak. And please to treat a symptomatic chronic subdural hematoma, it’s a simple, easy and fast procedure. And as with all our evidence here, we need, we do need prospective studies, of course. And again, for the third time, I would like to thank my fantastic team at Freiburg. And thank you.