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 “Iatrogenic Leaks: Surgical, How Common, and How Often are They Missed” 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] I would like to show you some iatrogenic leaks, how often do we miss them, or how common they are. Difficult task because the literature is sparse and the quality of the literature is not very high. I tried to give you some figures, some numbers, and if you look at retrospective studies, the incidence of dural tears is like 3.8 percent and searches online. So in prospective studies, of course, the incidence of dural tears is way higher, 10 percent in this study.
[00:00:44] And this is a prospective registry in Switzerland. So the data quality is quite high. And this was a simple, plain study of surgical decompression of lumbar spinal stenosis, and already in plain lumbar spinal stenosis the incidence of incidental dural tears was 10%. And this increases further if you look at instrumentation or or block vertebral body decompression or spondylectomy, the incidence of dural tears is going up to almost 20%.
[00:01:21] And if you look in redo cases, even for simple procedures, but redo cases—and it doesn’t depend on whether you do the redo case open or minimally invasively. —the incidence of an additional dural tear is 17 or 19.5, almost 20%.
[00:01:41] To give you some surgical cases, how a simple, straightforward dural tear looks like: this is not post-traumatic, it’s post decompression, lumbar decompression of the stenosis. And again you find these membranes in almost all of the cases, and then you first have to identify the real dura and don’t mistake the neomembranes for the dura, and then proceeds along the real dura to the site of the leak.
[00:02:08] This is shown here, and this was not a puncture hole by a needle. It was a typical puncture hole by a rongeur that is used during the—you see, even the jet CSF oozing out of the dura when you remove the little arachnoId layer you’ve nicely shown.
[00:02:25] And then I always put in a little bit of gel foam to remove the rootlets that are underneath the dura that you don’t visualize so when you’re suturing that you don’t incidentally suture one of the rootlets.
[00:02:39] And in a more complex case, in a post spinal fusion case, so revision surgery usually is you have to open wide and not, don’t use minimal invasive stuff. You need to remove the hardware and you’ve seen the rootlets here out of the thecal sac. Then we identify the borders of the dura. I think this is very important. Don’t just cover it and put some glue in, re-institute the borders of the dura. I think this is key to revision surgery for dural leaks, really not just covering it, but trying to build a new dura to suture in some substitute material.
[00:03:15] And then afterwards, then you can cover it and put in some dural substitute and fibrin glue, and there are many things that you can put over it. But first you have to reinsert the dura.
[00:03:28] What happens also the sequelae of iatrogenic spinal dural leaks, of course, they can cause intracranial hypotension.
[00:03:35] And also very important, I think there are many people actually suffering severe consequences, even death with the so called “remote” because it’s distant from the puncture site, “remote cerebellar hemorrhage.” You can cause herniation of the rootlets, even herniation of the cauda, up to paraplegia. And of course, venous problems, sinus thrombosis, epidural hematoma, complete spinal cord herniation, and in the long term superficial siderosis and two entities Wouter talked about this morning, bibrachial amyotrophy and frontotemporal dementia.
[00:04:12] So, how does it look like? Some examples from the literature, of course, you can see here the defect in the lumbar spine and a classical image of a iatrogenic intracranial hypotension with the subdural effusions.
[00:04:26] And this also can cause an epidural hematoma, so called spontaneous, but it’s not spontaneous. It’s a consequence of the hole in the lumbar dura. You can also get epidural hematoma and probably even worse, the Durret pontine brainstem hemorrhages, shown on the left on CT imaging and shown on the right in this very blood sensitive sequences, which usually have a poor prognosis.
[00:04:54] And the same goes for the remote cerebral hemorrhage. And I really do want to make the point that please do not use Redon drainages under suction after spinal surgery. Even if the surgeon is very confident, oh, I didn’t cause any tear or any leak, don’t use suction devices with a low pressure. Inside you have, we’ve measured this once., You can induce several hundreds of millimeter of mercury pressure with these Redon devices. And I encountered many horrible cases [that] were all places where I’ve worked with these Redon devices. And usually if you ask the junior resident, did you put the Redon, and, yes of course and I emptied it again and again so no problem with the Redon. So, really, this is not very high in our minds. Don’t use these drains in spinal surgery, they should be abandoned. I would like to make this point like [Dr. Ian Carroll] would like to make the point don’t use sharp, large needles for lumbar puncture.
[00:05:56] Another case of seizures and comatose state after surgery for the lumbar spine using these drains. Also, incarceration of the whole spine or incarceration of the cauda equina can happen after just plain lumbar discectomy. If the dura remains open, the rootlets can migrate out of the thecal sac and cause severe nervous symptoms.
[00:06:23] This is one instance from Bern, where two exceptional neurosurgeons, Karl Kothbauer and Rolf Seiler, who taught me a lot, both of them have published their experience here. Then, thanks to Karl Schaller, my friend, neurosurgeon in Geneva, who gave me a lot of his slides about the incidence of incidental durotomies, and he even performed a questionnaire in the ENS, in the European Society of Neurosurgery. How often do you think there is an incidental durotomy? And how then what’s next? How do you manage these patients? What are you doing if your patient has an incidental durotomy and even signs, clinical signs of CSF loss.
[00:07:05] So, as you can see, there is no standardized procedure at all. And some do bed rest, some do wait and see, 30 percent wait and see, some even put in a lumbar drain, increase oral fluid intake, bedrest, relative bedrest, strict bedrest, some do an MRI to identify the source, and almost half of them at least told in the survey that they returned to the OR for revision surgery.
[00:07:32] So the numbers are quite not so satisfying. There are no real good prospective studies and the incidence of durotomies and dural tears after surgery seems to be quite high.
[00:07:45] So, in the next part of my talk, I would like to tell you what to do. So my strong opinion is, if there is a leak, close it. Again, it’s very simple. It’s very straightforward. And the key is for me, not just to cover it or to put some glue in, just to reinstitute the border of the dura, suture the dura or suture some foreign material in if the tear is too big, and even open the dura on the dorsal side to reach to a leak at the ventral surface, as is shown nicely here in this paper from Nokhlo in 2017.
[00:08:17] So, don’t try to put glue around the thecal sac, just open it and close the leak at the level of the dura. Same goes for lateral leaks, and this is an image from a spontaneous one, but you can use minimal invasive surgery and you should always reinstitute the border of the dura or you can sandwich patch it from the inside and from the outside if the suturing is not possible. It’s still better than just putting glue on the outside.
[00:08:46] The same goes for large defects on the ventral side. This is an image out of a publication we did for spinal cord herniation, which in my view is a form of SIH, an abortive form of SIH, where the spinal cord tries to fix the ventral leak and these defects enlarge over time.
[00:09:04] And we can fix these leaks as well. And as in the iatrogenic leaks, it is key to reinstitute the border of the dura, not just peg it from left or right with muscle and fat, just try to reinstitute the border of the dura mater. And you can also use minimally invasive surgery for that.
[00:09:25] And this again is an example for spontaneous but you can use minimally invasive surgery for iatrogenic leaks. And it’s also I think a good way to approach from the contralateral side, so if the leak is here you should approach from the other side to always get the healthy dura first, reduce the neomembranes, and then you approach slowly to the bleb, the leak site, the scarring from healthy tissue.
[00:09:52] And then I would like to to share finally with you some attempts that we do and my team is doing. Some clever young neurosurgeons are trying to have some additional surgical techniques to help us with suturing and fixing these iatrogenic dural leaks. And one is a very often used method, it’s PRF, platelet rich fibrin, which dental surgeons use on a daily basis to fill the defects in, in after surgery for the teeth and it’s done easily in the OR. It’s chemical free. It’s just a centrifugation of the patient’s own blood. And then you can extract solid and fluid fibrin from the patient.
[00:10:40] So you have an injectable form of PRF and you have a solid form of PRF. And a solid form of PRF, it’s just like this jelly, you can squeeze the fluid out and you have a solid membrane, no foreign material, no chemicals, that you can really use for suturing iatrogenic and spontaneous defects in the dura. And you can combine it so you can kind of make a sandwich on the inside of the dura, then you suture it, you cover it on the outside of the dura, and you can then use the injectable, the fluid part of the PRF to augment your suture line. And this is also done in other specialties and there are so many good chemokines and factors in the PRF, in the patient’s own PRF, that probably also helps with healing.
[00:11:34] We’ve tested this in the lab. So, very simple setup, just a membrane. We made a hole in the membrane and sutured it and we repeated it with a PRF product. So you see both forms of PRF, the solid form, this is this membrane, and then we cover it with the patient’s own glue.
[00:11:54] And it was very simple. And the suture line ruptured—already it’s 10 to 50 millimeters of mercury—and if we just enhance the suture line with the simple patient’s own material the suture line ruptured only at 50 millimeters of mercury. And we also did a first clinical trial. It is not prospective, it is not randomized, but it is used in other specialties.
[00:12:18] And these are patients with a second revision surgery for failed lumbar fusion surgery, for instance, due to infectious reasons. No cases with a CSF leak, but still large wounds and problems with wound healing. And I think that we are 12 or 13 patients, and just putting in these solid and fluid PRF managed that these patients healed after the second revision.
[00:12:45] And we also try to use the solid and injectable PRF and these membranes, these custom made membranes out of the patient’s blood, in pituitary surgery. And I would like to show you one more. The next step, so to say what we are doing right now.
[00:13:03] So the first step is use solid PRF from your custom made membranes. And then we were tinkering around, one of my attendings was tinkering around with it and used injectable PRF and tried it—if you bathe it in 38 degrees water, it gets more jelly-like and then you have to wait for a certain point of time. I think we need to publish this. And then you have a kind of a combined solid and fluid PRF, you can put over the dura. You can see here this is a sandwich sutured after a terrible case of a CEO of a big company who is bedridden and there was iatrogenic leak. And so we sutured in the sandwich and then you put on the sticky dura—that’s how we call it, “sticky dura.” And then you press it down just for 10 seconds and it kind of coagulates and forms a really strong membrane with the fluid form of the PRF oozing into the all the tiny little gaps that there are. And then additionally, we use fat, so we use a layered approach, sandwich first, sticky dura next, and then even an epidural fat patch to support the construct from the dorsal side as is shown in the literature.
[00:14:18] This is for a case of a dural ectasia. So we used the patient’s own fat and adjust it and then we have a kind of a layered approach. First we use solid PRF membrane and sandwich technique, then we use the sticky dura, and then again after the fluid and the solid components have fused we use epidural fat to support the construct in these very desperate cases that we get more and more often in Freiburg.
[00:14:45] Okay, one more case. This is a case after plain decompression, plain surgical case in the lumbar spine, and many blood patches, and the imaging was called negative, but I mean you have this big bleb, but we have no clear contrast oozing out of the thecal sac in this imaging studies, and I was looking for the signs Andrew Callen just showed us, probably also negative concerning this, but there was a clear history. And in these desperate cases, I always trust the patients what they are telling me. And I did the revision surgery. And probably this is also a mechanism, I’m not sure. I want to share with you about the extent of these membranes that are forming after incidental or iatrogenic dural tears.
[00:15:34] So I approach from the contralateral side, from the healthy dura, then I remove the fixed membranes. And then it took, it takes some time to really dissect the complete scarring tissue and all of these neomembranes from the dura. And probably there was a tiny little small bleb that was not shown on imaging before. And then I continue dissecting all the membranes and the scarring tissue of the thecal sac and kind of coagulate the dura and then reinforce the dura and do the epidural reconstruction and this is just anecdotal evidence but it was very helpful in this case.
[00:16:15] And what I also always do in iatrogenic leaks, and I really recommend, it’s not always clear it’s iatrogenic and we let’s go back in, we always do studies with neurology before to try to find the exact site of the leak. It can be on the ventral side, it can be on the lateral side, and it can be an extensive surgeries, only at a very tiny little spot that is shown here, or is shown here as you see it, where the arrows are, a huge epidural pseudomeningocele in collection, but the actual leak is very tiny and you can suture and find this very easily after the studies, and you can also approach, even if there was a big surgery before, minimal invasively. And again, over several levels to the meningocele but just do one study and you find where’s the hole, where’s the leak, and how to approach it.
[00:17:04] Same goes for this case, it was more on the lateral aspect. Probably you would have missed it if you just go back in at the site where the primary surgery was performed. So you can use minimal invasive surgery in redo studies and redo cases as well. And one more case, which is done more often, the 360 patch for these desperate cases. Again, we do it minimally invasively, remove the membranes. And there was again, a puncture hole from, not from a needle. It looks like a needle, but it looks typically like the hole from a rongeur during a simple case of the lumbar discectomy in the median plane.
[00:17:42] But because we operated on this patient before, we knew that this dura might be very subtle. So we also did a 360, reduced the bleb, and refrained from suturing because the suture line always creates little holes. So we used these clips, atraumatic clips, that we don’t have a hole from the thread to the dura.
[00:18:03] And then again, do epidural seeding. And then I think this is key. The 360 patch is, there’s, we put tension under the 360 patch, and then an angled aneurysm clip to really hold it tight together. And in this case, we were at least lucky up to now in the short term.
[00:18:20] So to summarize, iatrogenic leaks, I’m sorry, I can’t give you high quality numbers, but they do occur quite often. I don’t have clear numbers, there’s no definitive test for it. So, in doubt, I trust my patients, and if they really tell me, “this is a different type of pain, it’s not the lumbar pain or the sciatica. I went to surgery for, but it’s just my life changed, I have a brain fog or have headaches,” I think it’s worthwhile to trust your patients and you continue work up, like in spontaneous leaks, use studies, use dynamic studies to find exact localization of the leak. It can be on the other side of the sequence, like it can be on the lateral side. And then do microsurgery. And if there’s a leak, just fix it.
[00:19:06] And what I’ve not shown you is that we had a ENS webinar a couple of weeks ago, where Lalani Carton Jones and David Scoffings, they showed beautiful ways to fix these iatrogenic leaks with fibrin glue. So this is, I think, worth a trial as well. And of course, I would like to thank my fantastic team in Freiburg, and I might continue for two more minutes because of the excellent talks of Ian [Carroll] and Andrew Callen with this chronic postural puncture headache— I think, at least, I really didn’t find a clear definition of it, and in the ICHD3, there is no real definition of chronic postural puncture headache, but this is just a very biased referral bias whatsoever, not prospective image of the patients we find in Freiburg, this I think were 70 or 80 patients, and out of Germany and Europe, but look at these chronic postural puncture headaches how severe this picture is.
[00:20:08] They were one year off from work for sick leave, they were at least in five clinics or consulted many doctors and, were one month in acute hospital care after this dural puncture. And to show you one surgical image again, we’ve seen some images after how this bleb looks like when we do surgery. And I’ve shown this video in Freiburg as well. So we called it the weeping dura. It’s a chronic post-dural puncture case. And once you identify the bleb, you can clearly, the CSF is washing the blood away, so you can clearly see oozing the CSF out exactly the mechanism Andrew Callen described. It’s not through the bleb, it’s next to the bleb.
[00:20:50] And we called it the weeping dura, like the it’s a, like a tear, and this is fixed easily. And this was causing the patient a lot of trouble. You can reduce it, reinforce it, and then it’s done. So thank you very much.