Transcript

- Ladies and gentlemen, welcome. Thanks for joining us. My name is Aaron Cohen and this is another session in a series of sessions regarding management of controversial and incidental lesions. This discussion today will focus on management of Chiari. Dr. Mark Proctor from children's hospital in Boston and Dr. Cormac Maher from University of Michigan. Gentlemen, thank you so much for your time, we really look forward to listening to your very valuable discussion, and Cormac please take it away.

- Thank you very much, Aaron. It's great to be back for another webinar in our series now of webinars on incidental findings. Last webinar, we discussed intercranial cyst, arachnoid cyst and pineal cyst and today we're gonna cover the equally controversial topic of Chiari malformation and syrinx and we're very fortunate indeed today to be joined by Dr. Mark Proctor, Boston children's hospital who is an expert in these lesions.

- Thanks Cormac, it's a pleasure to be here with you tonight and I look forward to the discussion.

- I'd like to start out today by showing you a case Mark that presented to our neurosurgery clinic about one year ago. This is a young man who volunteered for a clinical study and had this MRI taken of his brain and cervical spine. He was completely asymptomatic at the time, and again was just simply volunteering for the study to make a little bit of extra cash on the side because of the results of the study he was sent to the neurosurgeon for an evaluation. What would you recommend for a gentlemen like this?

- Well, I'd recommend you not volunteer for any more medical studies. That being said, I think this is a tough one because it sounds like clinically he's an asymptomatic patient. On the other hand, many folks might consider a high cervical syrinx that seems to be related to the Chiari malformation to be an imperative for surgery. So in general, in my practice, if I thought there was a syrinx especially in this location and relate it to the Chiari, I'd probably recommend surgery.

- And I think the vast majority of neurosurgeons would feel like you that with the cervical spine syrinx in association with the Chiari that they would be justified in operating and certainly that seems to have been the case. This patient however refused to have surgery and very interestingly, six months later returned for the follow-up MRI scan that he did agree to undergo, and it shows a nice resolution of his syrinx in that interval. And I certainly wouldn't suggest that this case is typical, I think, far from it but nevertheless, I think it is a illustrative of several of the issues that we face in dealing with Chiari patients and patients with Chiari and the recommendations that we need to make for their management. Although this is a very unique case, Chiari is often an incidental diagnosis and we all know that they should be occasionally treated surgically and I think for me, the difficulty is knowing exactly how occasionally that surgical treatment should be. The trouble is that there've been no large series describing clinical and radiographic characteristics of Chiari outside of our surgical series and very few studies describing the natural history of Chiari. A lot of our reports are based on surgical case series and a lot of what we know about Chiari is based on expert opinion, these reports and these surgical series. Mark, I have another MRI scan here on the right side of the screen. This is another patient who presented with migraine headaches, headaches lasting for hours, unilateral not associated with coughing, sneezing, and straining and yet there clearly is a Chiari malformation. What would you recommend for this patient?

- I think it's very important Cormac to align the symptoms with the findings. As you say, we tend to see a lot of children with incidental Chiari malformation. It certainly sounds in this case like the headaches are atypical for Chiari, and I would recommend that they pursue a headache workup and treatment outside of the Chiari before considering any surgical treatment.

- May I ask, what is this considered a typical headache for Chiari that defines it more of a Chiari headache than another kind of headache?

- I think most surgeons and authors would consider the typical Chiari headache to be a poster, cervical or occipital headache that's what's described as tussive in nature so worse with coughing, laughing, sneezing, straining of any sort. So the classic description in infants is that they will, or infants or young children is that they would laugh and then start to cry and that's you know, in fact I learned that from a pediatrician, that's what they're taught so that they have this laughing spell really increase their pressure and it causes them pain.

- Thank you.

- Mark can I ask a follow up question if you elect to not offer this patient surgery because you believe the headaches are not related to the Chiari malformation, do you think that re-imaging down the road is mandatory, and if so at what interval?

- You know, I would consider this a relatively mild sort of Chiari and I would say if the headaches responded to migraine treatment and were not problematic any longer, I would not routinely image. So I would, I think be a really led by the symptoms and what was happening to the patient over time.

- And final question on this case, would you restrict this patient's activity in any way?

- In general, if I don't think a Chiari is significant enough to require treatment I generally would not recommend restriction of activities but obviously that's a topic that has some controversy.

- Very, very controversial question which I think we're gonna get into a little bit more detail later on in the talk. So I think now Marc, you're gonna describe for us some of the challenges with Chiari management and think we'll start out with really the most basic question of all and that is what is a Chiari? How are we defining Chiari malformation?

- All right, thanks Cormac so I think there's a few, if we're gonna talk about treatment for asymptomatic Chiari is I think we have to define first, what is a Chiari malformation? Second, what is truly asymptomatic? And then we can sort of look at then who needs treatment or not. I think most authors describe a Chiari malformation as greater than or equal to five millimeters of tonsillar herniation. Certainly that's what the radiologists here at our institution would use as a threshold. There have been some articles in the literature, frankly it's mostly in the orthopedic literature that has challenged this and suggested that even as little as zero to two millimeters of tonsillar herniation might appropriately be considered a Chiari malformation in a patient with scoliosis. I personally think that starts us down a very slippery slope, because if you're willing to call zero to two millimeters, a Chiari malformation, you could be operating on quite a few patients. I think the next issue is defining what is asymptomatic. So what complaints are incidental and we just discuss the headache issue. So is a frontal headache an incidental finding? I think many of us would say, yes it is, but I don't wanna say it can never be related to the Chiari malformation. Chronic fatigue, polymyalgia these are very controversial areas. We'll go into a little bit more but here have been waves of surgery around the country and treatment for these symptoms and I think many of us would not agree with that. Is the syrinx a symptom of the Chiari? I think that's a question that depends a little bit on the type of syrinx but in general, most of us would consider a syrinx related to the Chiari to be symptomatic. Is scoliosis a symptom, and then finally do CSF flow studies, are they gonna make a difference in our workup? So regarding that sort of the polymyalgia and the chronic fatigue syndrome, and you know, is that controversial? In 2000, the AANS actually put out a position statement on the use of Chiari decompression for chronic fatigue syndrome. And you can see in the slide before you hear that you know, it was a fairly firm statement and, you know, there is no scientific evidence that chronic fatigue syndrome is a neurologic disorder or that it requires surgical intervention. And I think that was a pretty strong statement and it was done specifically in response to a wave of surgery being done around the country for a Chronic Fatigue Syndrome. So it's not often that our parent organization comes out with such a firm statement against doing a particular type of operation. So how about the Chiari I and Syrinx, and this would take us back to that first case. you showed me there. I think many surgeons consider a Chiari induced syrinx an imperative for surgery, even if there are no other symptoms. And that's sort of the category I looked at that first case, there was a survey done by Paul Steinbok out of Canada, looking at a survey of pediatric neurosurgeons and about 75% of surgeons considered Syrinx alone and indication for surgery. So I think that first slide was well within the scope of practice of most folks. And we do know that a syrinx can cause significant problems over the time. There has been at least a couple of good studies and the folks at the NIH have worked at this really symptoms of chronic pain syndrome that come on if you have an untreated syrinx. Couple of references here for you but to me a syrinx that I think is related to the Chiari is an important reason to consider surgery. That being said not all syringes are related to the Chiari malformation. This is a recent article that came out of our institution, and St. Louis where we looked at idiopathic syrinx in the pediatric population. And I think that's a very important topic to recognize that there are many syringes we see that are probably just developmental abnormalities and, you know, people talk in some cases about the Chiari zero, like in this slide you see before here, would this be considered a Chiari zero Or even though there is no appreciable Chiari, should you treat it for the syrinx? And in general I would be very reluctant to surgically treat a patient like this. So I think we have to represent this.

- Mark I have a question for you if you have a patient in the clinic with a higher level of thoracic syrinx, would you routinely perform a cervical MRI and look for a Chiari?

- Yeah, it's a great question And I think you know when you see these thoracic syrinx, I think there's a couple of steps that a lot of people will do. One might be to get better imaging to see is there a tumor related to it and in general these days, I think the high-quality MRIs are good enough that you don't necessarily need to get contrast to establish well is that a tumor sort of syrinx or not. But I think if it's a tiny dilatation of the central canal, I don't necessarily you know, go get that cervical MRI but if it's a syrinx sort of like the one you see in front of you here, I think that would warrant a cervical and potentially brain MRI to look for the

- Thank you.

- I think that's a very important point, especially in pediatric practice where we see a lot of children with these very thin, dilated central canals that are apparent on MRI imaging and frequently interpreted as being a syrinx on the MRI reports and frequently prompting a neurosurgical consultation, especially in the kids with scoliosis. We see that a lot at the point of the curve, a little bit of this dilated central canal. And really, I think it's very important to make a distinction between that and through syringomyelia. And for me, when there is a true syrinx so to answer your question I always do image to see if there's an associated Chiari malformation or tumor.

- Hey Cormac, how do you differentiate between a dilated central canal versus syrinx?

- Well, that is an extremely controversial point and in some papers we wrote recently, we tried to establish exactly how we were gonna make that distinction in a way that that other people would accept. And what we decided to do was consider everything larger than three millimeters, a maximum diameter syrinx, now that's an arbitrary number. Other groups have done the same thing also for arbitrary reasons, but it's a number that does tend to weed out a lot of those dilated central canals and you're left with mostly real syringes in your population if you use that three millimeter criteria. I don't know Mark, you have an opinion about that?

- Yeah, I think you know, I'm looking at the article we published here, we generally say two millimeters or less is probably fairly unconcerning. I think it's partly it's size, partly there's some other factors like do you see little haustral lines within the syrinx that may be a little bit more concerning? But I'd say if it's on the order of two millimeters or less,

- Thank you.

- I generally don't think twice about it. Okay, and so the other question that comes up then what about Chiari and scoliosis? So scoliosis is seen in about 85% of patients with Chiari and syrinx, once you get the syrinx with fairly high incidence of scoliosis reported in the literature. But it's fairly rare for you to see a scoliosis and a Chiari with no intervening syrinx. So I think it brings up a question is a patient who has a scoliosis and maybe a little bit of a Chiari, is that a symptomatic Chiari malformation? In general, I have been reluctant to consider any surgical treatment for that if the patient does not have any other neurologic findings or any other symptom. Patient with a Chiari but no syrinx is sort of an undefined problem and I would generally consider it likely asymptomatic but some would consider it symptomatic.

- Mark, I have a question. Does every patient with scoliosis especially in the pediatric population, should undergo MRI imaging through a lot of syrinx?

- Cormac and I are both smiling, very controversial area, yeah. I was once at a combined neurosurgical orthopedic meeting, and I suggested that any patient, not every patient with scoliosis, but any patient who had scoliosis who was gonna undergo surgery for it should have an MRI scan and it met with a lot of resistance from the orthopedic surgeons who feel that there are some cases that are so classic for idiopathic scoliosis, that they don't need imaging. That being said, once the rods are ran, it could be hard to get good imaging of the spine and I've certainly seen cases that were thought to be classic idiopathic scoliosis that were the result of a Chiari and syrinx.

- Thank you.

- So in general then how do we define asymptomatic Chiari? I would say if you have greater than five millimeters of tonsillar herniation so now we know you have a Chiari. No clinical symptoms of a Chiari malformation so you don't have excessive headaches, any cranial nerve findings, any neurologic issues related to it, you don't have a syrinx related to the Chiari. And again, I would say the issue of scoliosis is undefined. In my view, the CSF flow study results do not necessarily make otherwise asymptomatic patients become symptomatic.

- Mark, I have a question, What are these, besides the headaches we talked about that I appreciate your discussion. What are the non syrinx related symptoms that you can clearly or at least most likely attribute to a Chiari? So if we take out the symptoms related to syrinx, what are the symptoms that are more bonafide related to a Chiari?

- So I think again, topping the list would be the poster occipital and/or poster cervical headaches, if we look outside of the syrinx and scoliosis, then you know the symptoms I always ask about in my practice, is any issues with diplopia, does the child have any trouble eating or swallowing? I always ask about snoring I think you know, clearly anything related to cranial nerves can be there. I think at least in a child it's gonna be very unusual to find cerebellar signs, ataxic and the like, not that it doesn't happen but it needs to be a fairly significant Chiari for that to happen. And you know, depending on how severe the Chiari gets, you can start to see long track motor findings as well.

- Thank you Cormac, how about you, what do you think?

- Well, I agree with that. Unfortunately, Chiari is a common enough finding on imaging that almost every symptom you can imagine has been associated with Chiari in the literature and I think we have to be a little bit careful as we get farther and farther down that list of Chiari symptom attributing this symptoms to Chiari. But certainly everything that Mark mentioned are common Chiari symptoms and patients with these types of symptoms, the headaches symptoms, the snoring sleep apnea, I think need to be considered Chiari symptoms until proven otherwise.

- Thank you gentlemen.

- I should say that the typical headaches obviously because headaches are very very common not caused by Chiari.

- Thank you.

- So then what are the main reasons we have to operate on an asymptomatic Chiari malformation if we're gonna define it as asymptomatic, what might prompt us to operate? And I think there's probably three categories. One is that it may become symptomatic over time, the other is that it may result in a brain or spinal cord injury if left untreated. Frankly to me, the fact that it may become symptomatic, I'll wait till it's symptomatic that doesn't bother me. But I think one issue we wanna address this discussion is what is the risk to the patient over time if they have a Chiari that's not treated, can they suffer a spinal cord injury or a brain injury? And the third issue is, is it likely a syrinx is gonna develop over time? I would say in my practice, that would be really relatively anecdotal I don't think that happens often but I think it can happen and I think Cormac's got some data to look at that a little bit.

- Right, so I'm gonna share with you the results of a few studies that have been carried out recently on Chiari malformation. Trying to address some of these issues I think one of the pieces of information that would be useful to have on Chiari malformation is what the population prevalence is, we still don't know the answer to that but we can at least start to address questions like what is the prevalence on at least those undergoing intracranial imaging. And also it'd be nice to know more natural history information on Chiari malformation. Just as Mark is saying, if we elect to not operate on somebody, what does the future hold for that child, are they destined to become symptomatic later, could the Chiari resolve on its own? But we really don't know until the results of some recent studies have started to become available. This is a very nice study from Johns Hopkins that came out in JNS in 2000 Meadows and others, where they looked at 22,000 consecutive patients that underwent neuroimaging at their institution. They don't specify age groups in this study and I believe that most of these patients were adults, but they came up with incidents on imaging of 1:150 individuals. So not uncommon finding on neuroimaging at Johns Hopkins. We performed a similar study recently that's coming out in JNS next month, where we looked at 14,000 consecutive children that underwent neuroimaging at our institution and we found that about three and a half percent of all children that had neuroimaging at our institution for any reason had a Chiari malformation and this didn't change significantly across different age groups. You can see that girls were a little bit more likely than boys to have Chiari, but not as much as we might've thought. Again, bringing up the point that I brought up in the last webinar, that if Chiari is a very, very common finding on those undergoing intracranial imaging, we have to be very careful when describing a relationship between this common imaging finding and common symptoms. Turning to the prevalence on imaging of Chiari malformation and syrinx, it looks a little bit different than just the Chiari by itself prevalence. Here, we can see that there's a definite female preponderance. It's half a percent in males and over 1% in females, doesn't sound like a big difference, but with the large numbers of patients involved, there was a very, very strong difference between those two groups. And another thing that I found interesting is that unlike Chiari which didn't change much over ages, sex was very, very rare in the young kids, basically not seen in our study in the infants, and then relatively rare early on, becoming more and more common so by about the age of five, it seems to flatten out. A little statistical noise, but basically flattens out, indicating that if you're born with a Chiari and those syrinx, those first few years of life, the prevalence of syrinx does seem to increase significantly. Syrinx formation does seem to be related to the degree of tonsillar herniation. There was a small study that came out in the Red Journal about 10 years ago, which suggested that there was a sweet spot for syrinx formation and that those without much tonsillar herniation were not as likely to form syrinx as of those with more tonsillar herniation but that if it increased past a certain number, you became less likely to have a syrinx again. In other words, the theory was that there was some spot up here where syrinx formation was most likely. In fact, we didn't find that to be the case as much larger numbers we found that syrinx formation was increasingly more and more likely the more tonsil herniation you had, again shown here by the red bars being the syrinx and it just seems to get more common until about 20 millimeters or so where it doesn't change much anymore. But again, this makes sense I think if you think about it, the greater the degree of tonsillar herniation, the more likely it is to be associated with the syrinx. I think prior studies have suffered from smaller numbers and haven't really been able to show that. In terms of the syrinx location, I think most people agree that cervical syringes are most likely to be associated with a Chiari malformation and we did find that interestingly though, we also found that there was not a trivial number of purely thoracic syringes. These are syrinxes as they came up to the thoracic spine at their most cranial extent, didn't have any cervical syrinx extents at all. I thought that there might be an association with scoliosis in these patients and that these might be syringes associated with scoliosis rather than Chiari and in fact, that wasn't the case. These were in many cases, syringes in patients with Chiari and without scoliosis. So I think people should keep in mind that just because there's no cervical syrinx doesn't mean there's not a syrinx although it's most common in the cervical spine, you definitely can see isolated thoracic syringes in these patients. This is an excellent study out of Italy that came out a couple of years ago, also published in JNS. And it was really the first good study we had on the natural history of asymptomatic Chiari malformation. DiRocco and others followed 11 asymptomatic patients for a mean of six years and 23% did have worsening of symptoms and 14% required surgery, but this was considered by this group a relatively low number, there were no catastrophic events although the authors didn't comment on any activity restrictions. There was an excellent editorial that accompanied this article, which suggested on the basis of this relatively benign natural history perhaps we should be calling this a Chiari anomaly, rather than Chiari malformation it's a term that I like also, although it never really got any traction in the two years since publication of that article. So another excellent study shown here from the university of Miami, this came out just last month in the journal of neurosurgery, a much larger natural history study now on 124 patients that were followed, 14 developed symptoms. Again, emphasizing that generally benign natural history of the Chiari malformation. And then finally, this is our natural history study on Chiari malformation is coming out I believe in next month's issue of the journal of neurosurgery, we followed 148 patients. Not all of them were asymptomatic, but all of whom at least we had initially made a decision to pursue a conservative treatment. They were followed from mean of four and a half years, 16 patients required surgery. Not all of those patients did worsen some of the patients had stable symptomatology and then had a surgical decision made because of stable symptomatology but 16 patients out of 148 did require surgery. Again, emphasizing that generally benign natural history of this condition after the decision for conservative management has been made. I think this is a graph which summarizes our data well. As you can see, its almost a bell curve or Gaussian distribution in terms of what the changes were in tonsillar herniation over time. The tallest bar you can see is zero change. Most patients didn't change in tonsillar herniation over time. Some patients, as you can see with these bars did get worse over time, a couple of patients very substantially worse over time. But then offsetting that, we also had patients that got better over time and some patients dramatically better over time. So I think it's fair to say based on this that most of our patients stay at approximately the same, but you definitely can't take that for granted. Some patients get dramatically worse in their imaging, some patients get dramatically better. Just as an example, here's a two year old boy, the image on the left you can see a Chiari malformation, same patient image two years later with a resolved Chiari. Six year old girl and other patients shown on the left, Chiari malformation and again on the right, it did seem to resolve. Some of this is a real improvement in my view and some of it I think if you look at this image, there's a little bit of a difference in terms of inflection and extension of our MRI. I think that needs to be taken into account and it's never really been taken into account in most Chiari studies, we have a study currently underway looking at that issue. And then finally looking at the changes in the syringes over time, a little bit to the same story as what we saw with the Chiari images. Looking at this, this is a change in syrinx length and again, the tall bar shows that most of them didn't change over time, but some got worse over time as you would expect and this was interesting to me, I didn't expect this at least not in the numbers that we saw. Some syringes improved over time and a couple of them substantially so. In our own practice, we have found that CSF flow studies have not been particularly helpful and this was born out by our data that is presented in some of the studies that I just shared with you. And the reason for that is that it is a very accurate marker of worse disease, those with increasing tonsillar herniation, those with peg configuration are definitely more likely to have a worst CSF flow on a CSF flow analysis. It also correlates very nicely with increasing symptoms. The trouble is, is that when we use it as an independent parameter at trying to predict who's going to do well with surgery and who's not going to do well, we've found that it's not been much better than our own clinical criteria, such as the worst MRI appearance or the worst clinical symptoms. Mark, what do you think the role is for CSF flow analysis in these patients?

- I would agree with you Cormac that I think it reinforces my clinical impression, but it's rare that it changes my impression. So if I feel a patient is symptomatic and likely to require surgery, I think the flow study is generally supportive of that. Similarly, if I feel a patient is not symptomatic from it, when I get a flow study, it tends to be normal. Sometimes the flow is a little attenuated dorsally, but pretty normal anteriorly. I think that, you know, the slide here certainly supports us. These are a couple of studies that have discussed that issue there's a study out of Wisconsin showing that the results of the CSF flow study seemed to correlate with a clinical impression and certainly symptomatic patients oftentimes the CSF flow studies is gonna show that the CSF flow is diminished and that's been correlated with good outcomes but it's very rare that you'll find a study that shows that the CSF flow study is better than your clinical impression. So to me, it's a good supportive test but I don't think its ever really completely swayed me against what I've thought of clinically.

- Thank you.

- Another issue to discuss is the the effects that Chiari can have on trauma and can a Chiari be worsened after trauma? And there's a few studies that have looked at this a very good study by Dr. Tator out of Canada where he had a series of 85 Chiari patients that were operated on and 13% of them had become symptomatic after a minor trauma. And I think there's clearly some evidence that in some folks the Chiari can become symptomatic after some sort of a relatively minor trauma. Again, does that mean if you see someone with a Chiari malformation you should operate on them expecting that they can become symptomatic. Certainly in this study, none of the folks had a bad outcome and they all responded well to surgery. Several case reports in the literature that do show what would appear to be worsening of Chiari after trauma, a few of them listed here, again a couple more here. And then just to reinforce sort of the worst case scenario and that would be obviously sudden death. There have been a couple of anecdotal reports of sudden death in patients with a relatively minor head trauma, and then just found after they in fact did have a Chiari malformation. But I think these are really very few and far between and clinical practice certainly would not necessarily support routine operations to avoid this complication a routine restriction of activity.

- Mark, can I ask you what you think about this case report, is it your opinion that the Chiari actually did lead to the sudden death in these cases? Or do you think that there's at least a possibility that the Chiari was discovered by the anatomic pathologist after a death from other reasons and was thought to be highly abnormal and therefore probably causative?

- Yeah, I think it could certainly be coincidentally.

- Thank you.

- This is a sort of an interesting case from our institution of a 13 month old, who fell down a flight of stairs and was actually imaged with an MRI scan because he wanted to get cervical clearance and the child did have a little bit of ataxia. So on the CT imaging, we could see a little skull fracture in that area and the MRI was done and as you can see here, things are a little tight at the foramen magnum. On this next slide what you can see is that the child actually seems to suffer a little bit a contusion of the cerebellar tonsils, probably because there was a bit of a preexisting Chiari malformation and the trauma exacerbated things. Six months later, interestingly, not only does the contusion gone but there's not really that much of a Chiari, just a little bit of a Chiari so perhaps it's a chicken and an egg phenomenon here, I can't definitively say this was a Chiari that got worse and as opposed to just a pure cerebellar contusion. Another topic that comes up a lot, especially in the discussion of restriction from activity is can you get a spinal cord injury? And if there's a Chiari malformation, obviously you can see the anatomic basis of why it's possible because you know, someone with a Chiari, the spinal cord can be a little bit compressed at the level of the foramen magnum. There's really only incidental and anecdotal reports of spinal cord injury after minor traumas and these are all in patients that had a trauma, had a spinal cord injury and after the fact they find out they have a Chiari malformation. So to my knowledge there's never been found in a prospective study where you follow a patient with a Chiari malformation and then they go on to have a spinal cord injury. So again, I think this is something that you know, it obviously has a high degree of anxiety about it because these reports are out there, but how likely you are to suffer a spinal cord injury because you have a Chiari is really unclear and probably the incidence is very, very low. Again, there's several case reports relating spinal cord injury to the possibility of Chiari but these are all Chiari is discovered after the fact. Showing here, is a patient of mine several years ago was a 15 year old football player who presented with what he perceived as ataxia. He clearly had an ataxic gait and that's what led to the imaging and on exam had pretty profound upper motor neuron findings. And you can see this is a pretty significant Chiari, the cerebellum is really squeezed out going almost down to the C23 junction. So we did decompress this young man and the next slide here you could see after decompression, I tend to especially something [Inaudible 37:07:69] So the configuration of the cerebellum was far more normal but there does seem in this area where I have a narrow to be a small contusion in the spinal cord. He was markedly improved but still had some hyperreflexia and I did not feel safe returning him to football based on the abnormal neurologic exam and the MRI scan showing these cord signal changes. And that does bring [Inaudible 37:38:61] an athletes and I think there's a lot of, as I said, a lot of anxiety around this cause if you go on the internet and you've just been diagnosed with a Chiari malformation, you can find a lot of bad stuff that can happen to you. Very interesting and in this day and age with the very significant awareness of concussions is you know, as you were pointing out earlier Cormac, you have certain segment of patients that have Chiari, certain segment of patients that have concussions, two fairly common things well when you see a patient with a concussion also have a Chiari, are they related? I think the jury is clearly out on that one. I think most likely off a lot of those are incidental. Drop attacks have been reported, and the biggest question then is, is an athlete with an asymptomatic Chiari, especially if they're doing high impact sports, are they at risk for catastrophic injuries? This is just sort of an example of a case like that. So here's a patient I saw presented after motor vehicle accident had a little bit of arm weakness referable to the fact that they had this little bit of a fracture here and had a little bit of a radicular symptom on the MRI scan, in here you can see maybe a little bit of that disruption in this area but what I was impressed by was this Chiari malformation here, which I thought was at this point completely incidental I did not think it explains his clinical findings. However as he recovered, he wanted to know could he get back to sports? He was a fairly avid athlete, and I think to me that's a tough one, but he made a full recovery from a C5 radiculopathy. He had no symptoms of a Chiari malformation and like I said, if I don't think the is bad enough to warrant surgery, I'm generally not gonna enforce an activity restriction. I do think it's important that the athlete and the family understand that there is this concern that this is out there in the literature, but that most people here in my practice do not restrict athletes simply because they have a asymptomatic Chiari. This is just that same athlete a few months later everything's really healed up nicely here but the question is, is this Chiari enough to restrict him from sports? And if you're gonna restrict sports, which sports is it? Is it just the high impact contact sports like football and hockey and wrestling, or is it all sports? And I think that it's really an unanswered question. And then what about a treated Chiari malformation? So this was not a asymptomatic Chiari, this was a significantly symptomatic Chiari. Whenever she looked up, she would get a lot of neck pains and she was a pole vaulter. I think probably the only pole vaulter I've ever seen in my practice. So we did a decompression and here she is after surgery, is this young woman able to get back to sports? And in general, I would say yes. After I decompressed the Chiari malformation and they are now asymptomatic or recovered, I do not restrict activities. Do you have any thoughts on that Cormac, after surgery should there be restriction?

- I agree, I think a bias against activity restriction right now especially with as commonly as we're seeing it these days, I think that restricting a child's activity is making a major change in that child's life and I think if we are going to do that to a child, we should have some basis for that, some pretty sound evidence that by restricting that child's activity, we're actually going to prevent a significant harm. And right now, I think we're unable to say that, we have these anecdotal reports of injuries, which in many cases, it's not clear if they were related or not. I believe that Chiari malformation does put you at some small increased risk of injury, but we've never defined exactly what that risk is. And I think until we're able to do that, I don't wanna restrict the children that I see from participating in a sport that they enjoy. That's gonna have a big impact on that kid's life and we can't provide any data to support that decision. But like you, I always have a frank conversation with the patient's family about these types of issues, I share with them exactly what the state of our knowledge is and why we make these sorts of decisions, I'm careful to tell them that other neurosurgeons do restrict activity in the presence of a Chiari malformation and that at the moment, it's really a matter of differences of opinion in our specialty.

- Thank you. So if we sort of summarize the whole data on Chiari malformation and sports, I would say a symptomatic Chiari malformation to me is probably a contra-indication to contact sports because that's when I would recommend often treating. And like we just said an asymptomatic Chiari, it may be a relative contraindication due to increased risks, but we really can't support that well with the literature and I think it's important to have that discussion, but I do not enforce strict activity restriction. Most athletes can return to the sport after Chiari decompression.

- Thank you, Mark. I've just got a couple of cases that I'd like to show you now if that's okay. This is another patient that presented to our practice, it's a three-year-old with a developmental delay. The motor delay was worse than the language delay. His examination was really quite normal, except he did appear to be a little bit delayed for his age. His gait was perhaps a little bit imbalanced for a three or four year old boy, what would you recommend for this family?

- You know it's again, not a completely straightforward case. It's no data, real Chiari malformation I would estimate those tonsils to be down probably eight to 10 millimeters or so. Another thing I like to look at is the configuration of the tonsils, are they rounded or are they a little pointed? I'd say in this case, they're sort of in between the two, probably a little bit pointed. So I certainly believe this is a Chiari malformation that could be symptomatic. So then the next question is, are these symptoms related to this? You describe a little bit of gait ataxia, motor delay or some speech delay. So I think it's one where you know, I couldn't definitively say that one plus one equals two on this, but I would certainly consider surgery a reasonable option, I think we can potentially support that decision with things like a sleep study, this might be one where, despite what I said earlier, I might consider a flow study to say well, was the flow really diminished in that area? I'd consider imaging of the spine because if there was a syrinx to me that would be something that really pushed me towards surgery. This is one where I think a decompression would be reasonable, but the family would have to understand that it may help.

- Aaron

- Yeah, I have a question. So you are really saying that the flow study is really gonna convince you one way or the other on a very questionable case, is that correct, mark?

- Like I said, it's rare that it's gonna completely change my clinical opinion, but this is one where my clinical opinion is probably right in the middle. So I you know, it's hard to firmly commit those symptoms to being from a Chiari malformation, but I think that's to me the case where the flow study might be of some utility.

- Just as a follow-up question on this case Mark, if you don't mind and I think I've got a sense for what your answer will be, but if you choose to not operate on this child, will you recommend any activity restrictions?

- Yeah, generally not. And especially, I think it's almost impossible to restrict a four year old. You know, they're not out there doing the contact sports and you can't lock them up and watch them.

- And would we recommend re-imaging?

- Repeat imaging I think you know, interestingly, perhaps my opinion on that's changed a little bit after seeing your data because I was gonna ask you at the time, you know, this sounds like in the four year old age group, this is one that's not likely to have a syrinx, but maybe a little bit more likely to have a syrinx later on or based on your data on the syrinxes, what would you say about re-imaging.

- Frankly, I think even with the new data, the answer to the question I just posed to you is not known and not in a data-driven sense. I personally would re-image this patient but I can't say that that that's supported by the literature or not, It's just what our clinical practice has been. If you look at our prevalence data, it's true that those in the younger age groups were less likely to have a syrinx than the Chiaris that we're detecting at the older age groups. That's not quite the same thing as saying the natural history of a Chiari at age four is worse than the natural history of Chiari at age eight. But it is true that he is more likely to have a syrinx when the Chiari is detected later. So yeah, in my own practice, I would re-emerge this patient. If I was convinced he was completely asymptomatic, I'd probably re-imaging a year. That's a arbitrary number, that again is not data-driven. But I think that really right now, any practice is equally supported by the literature.

- So let me ask you on that Cormac, are you re-imaging cause you're looking for a development of a syrinx or because you think the Chiari is gonna change?

- And also I think like you, I deliberately made this case I think controversial, and like you, I think I would have a very difficult time deciding whether to operate on this child and deciding whether this child needed surgery. If I chose to not operate on this child, I would wanna follow him clinically. I would wanna be interested in knowing how his development is progressing, whether he's developed any new symptoms, whether his exam has changed. And I think a part of that is re-imaging, and again, if I'm on the fence a year from now, when he continues to be developmentally delayed with a essentially a normal neurological exam, maybe a worsening scan would help knock me off that fence one way or the other. A worsening scan might lead me to suggest surgery in a year. So like you recommending the flow study although it may not be part of your usual practice to use that as a major criteria for deciding for or against surgery, I think re-imaging here may help me decide whether to recommend surgery in the future for this child, because it is, I think a very controversial case.

- Yeah, I have a question. So you're gonna re-image the patient, if his symptoms is not changed, are you gonna operate on it if it's a little bit worse?

- Well, I think these symptoms would fall into a gray area for me where there may be some motor delay for unclear reasons. And I think if he's developing a syrinx yeah, I think at that point I would feel justified in offering surgery for that family. Like most Chiari patients, I would again share with them exactly what the data are right now, what the natural history data are, what our surgical resort results are and be guided to a large extent by their opinion. But I think if he develops a syrinx over the next year and his symptoms remain the same, then I think the surgical decision would be justified. Mark, do you have an opinion about that?

- Yeah, I think that all sounds reasonable. I probably would follow that same paradigm.

- Thank you.

- I have another case that I was interested in showing you Mark. This is a, let's say a four month old that's been diagnosed with failure to thrive by the pediatricians. This child has been vomiting, not feeding well. The pediatricians have ordered this MRI scan which was interpreted as showing a Chiari malformation and now the child has been sent to see the neurosurgeon. What would you recommend for this family?

- It's an interesting case. I mean, interesting in part, because as you look at this and you look at the shape of the head, this child clearly seems to have an element of plagiocephaly and there are definitely folks out there that think that the increased incidents of occipital plagiocephaly from probably back to sleep program. So the babies sleeping on their backs, maybe leading to some degree of increasing Chiari malformation. That's more opinion than what you're gonna find in the literature. But this is a child who clearly has a lot of occipital plagiocephaly and really what you'd call turricephaly where the back of the head really rises up and probably can lead to a little bit of the cerebellum being pushed down. You know, arguably perhaps a non-surgical way of treating this is to improve the shape of the back of the head, if you can round that out, maybe there would be more room for that cerebellum. Certainly, we see that in craniosynostosis patients, that an indirect way of treating the Chiari is to do an expansion of the occiput. Slightly off topic I would say in this child, you know, those symptoms again, perhaps a little nondescript vomiting in a baby, lots of four months olds are going to vomit. And I think it's probably worthwhile to try and establish a little bit more, why is that child vomiting? Is it a problem with swallowing, could your ENT colleagues look at the vocal cords, might you consider some other sort of tests like a swallow study to see if the vomiting is triggered by a swallowing mechanism or disfunction?

- If there was vocal cord paralysis Mark, would you use that as a justification for surgery?

- I think I would. I think, I mean that's to me is one of the few clear indications in an infant. Cause I think it's generally very hard to tell if an infant is symptomatic from a Chiari. But if there is a clear vocal cord paralysis or swallowing trouble, that seems to be symptomatic, then I think you're probably obliged to decompress that.

- And with this child, just as you had suggested, we also thought the child had plagiocephaly the symptoms in point of fact actually were not as severe as in the scenario that I gave you and this child was re-imaged after several more months and the Chiari did seem to resolve over time as the head shape normalized.

- Great, so I think in conclusion, I think what we could say from this discussion today is that with the increased use of MRI scans, there's no doubt we're seeing more and more asymptomatic Chiari malformations, and you know, for a lot of families, as I'm sure you've both seen in your practices is that they come in, they've ran all about Chiari on the internet and they're scared, they think they have symptoms. And I think I spent a lot of time talking people out of that you know, sort of saying well, you know, don't be so concerned about the presence of this Chiari malformation and maybe you're right, maybe I think you said Chiari anomaly, maybe that's a little bit of a better description. I think there's clearly no consensus about the management, symptoms can progress and then you could treat it at that point. I think in my view, there's inadequate data to support any prophylactic surgery as a standard. And I'd also say that, although there's anecdotal reports about the potential risks of brain or spinal cord injury in some of the Chiari malformation, I think it remains anecdotal and I think a prospective series would be needed to quantify that risk.

- Thank you very much Mark.

- Cormac and Mark thank you for a very, very thoughtful discussion. It was extremely useful, very valuable data in terms of directing our viewers at least further in terms of managing their patients. Before we finish, I'd like to ask you guys a question. When you do this surgery, I personally use a dural graft and open the dura, open up the adhesions, and then you do a dura plasty with the aloe graft. What is you guys' preferences during creating Chiari surgery? Some people just use the ultrasound, don't even open the dura, and some people open dura, I have even heard they don't even close the dura, which I don't think that's very well recommended. So what is the best practices in terms of decompressing the posterior fossa after craniectomy?

- Well, how about I go first and then Mark can correct everything that I say and give the right answer. I think Aaron you're ending the seminar with probably the most controversial question you could have possibly asked and I think definitely there's not a right or wrong answer for this, I agree with you. And in my own practice, I open the dura virtually all the time, I also use an allograft, my partners never used an allograft, they usually use pericranium instead of allograft and seemed to have excellent results with that. One of my partners opens the dura selectively, and not always and does use ultrasound as a basis for that. And as you've alluded to, I think there are excellent surgeons around country that are almost always doing bone only decompressions and not opening the dura. In my own opinion, I think in cases, especially cases with the syrinx which is the majority of my surgical practice is patients with syringes. I think I can justify opening the dura I think if you're very, very careful with closing the dura on a watertight manner, the risk of complications from that is very, very low. And so I think at least in my practice, I can justify opening the dura with a nice watertight closure. I think if you don't spend some time making sure your closure is water tight, then opening the dura definitely has an increased risk versus the bone only decompressions and it may be harder to justify in such a practice because in many cases, the bone only decompression has good results and I think what we're talking about even for the believers in opening the dura, in every case, what we're talking about is some incremental improvement in the percentage of syringes that are gonna resolve and the percentage of patients that are gonna get better. It's not a dramatic difference but I think it's a small incremental improvement. And you pay for that with some small incremental added risk of CSF leak and that's where again I can't emphasize enough you just have to be so careful with closing the dura in a watertight manner. These patients can be miserable if they have postoperative CSF leaks, or postoperative pseudomeningoceles. And you mentioned the practice of opening the dura and not closing the dura. I've heard of that, I've never seen it done and it seems to me that patients with large posterior pseudomeningoceles probably won't be very happy so that's one practice I personally couldn't endorse. So that's my answer Mark, what's the right answer?

- Well I have to say in this case Comarc, I agree with you on both counts and that's the most controversial question Aaron could have asked. And two is that, I think that in my practice, most patients are gonna get the dura open and use an allograft. Certainly, any patient with a syrinx, I'm gonna clearly open the dura. Rarely I will do a bone only decompression, but generally there have been some other factors that have pushed me towards that. I think what the literature is starting to show when we hear these presented at meetings, is that when you do the bone only operations, that the complication rate is a little bit lower, not much lower, a little bit lower, but clearly the re-operation rate is a fair bit higher. So in my view you know, the patient, they don't wanna go through this operation twice. And from their perspective, the healing is gonna be pretty similar, whether or not you open the dura in the vast majority of patients.

- Okay, well gentlemen again, thanks very much, this was extremely helpful. and we look forward to having both of you along with us for the future sessions. Thank you to our viewers also for being with us and good night.

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