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I'm joining online and thank you for joining us and for our last session of screws scalpels and suspicious. And we're going to talk about neurosurgery and EBD tonight. Um My name is Emily, I'm one of the F twos working in neurosurgery in Bristol and I've got Scott with me as well. Um Who you've probably met from some of our earlier sessions. Our learning objectives for this evening are to recap and know your basic neuroanatomy and neurosurgical principles. To understand the history, examination, investigation and initial management of two neurosurgical emergencies and to understand the management of external ventricular drains on a ward level. So that's kind of the level that you would expect from your F two on the ward. Talking about neuroanatomy. I thought we'd start from the scalp and work our way inwards and really the nicest way to remember this I think is with the pneumonic scalp. So, starting with skin and dense connective tissue. The next layer is the epicranial aponeurosis or the galea Aponeurotica um followed by loose areolar connective tissue and then periosteum. And this is something I've got, I've been asked a lot and anytime I've been in theater because I think the surgeons like to make sure you're thinking about the layers you have to go through for any kind of neurosurgery. And it shows that you're engaged and interested. I think it's quite a good starting point for, for thinking about how we approach neurosurgery. Following on. From that, we've got the skull itself and then underneath that the meninges. So you've got your dura matter, then the subdural space underneath that arachnoid matter and the subarachnoid space and the pia mater underneath that is the brain parenchyma. Um The spaces that we talk about are very clinically relevant because if you're talking about any kind of intracranial hemorrhage, you want to know where that blood is and commonly it is in the subdural space or the subarachnoid space. You've probably heard about the an extradural bleed as well. But that strictly speaking isn't an anatomical space, but it is a potential space for blood to collect. Um It's also worth mentioning that jura matter means the hard matter. So it's quite a tough connective sort of fibrous tissue. The arachnoid matter means spider matter and spider mother. So that's the kind of trabecula that you see in the subarachnoid space. And then the pia mater pia means delicate and that's the the most delicate layer that is adherent to the surface of the brain itself and it follows the sulci and gyri of the brain very closely. Whereas the dura and and arachnoid matter sit more on top of the brain, they don't follow its course. Moving on from that, then we'll talk about the jura venous sinuses. Um The Jura has four main folds that help to separate the components in the cranium. Um clinically relevant are probably the falx cerebri and the tentorium cerebella in the falx cerebri, we've got the superior and inferior sagittal sinus. And I would say that the superior sagittal sinus is very clinically relevant because um you want to avoid it in the midline. And when you're considering your potential approach for any kind of neurosurgery, you want to make a note of your midline, but make sure not to avoid it. Because if you drill through the midline, you will hit the sinus and you'll have significant venous bleeding and that can be quite hard to stop. Um So bear in mind that your, your dura venous sinuses are very closely adherent to the bone. Um because of the layers of dura that we'll talk about in the next slide. So um knowing where your transverse sinuses and uh sagittal sinuses are as well as um sort of the inferior sinuses as well. It is important for planning your surgical approach in terms of the tentorium, cerebella, its main ii suppose it's an important anatomical landmark and it helps us separate the cranium into supratentorial and infratentorial with infratentorial being the cerebellum and the brainstem and the supratentorial compartment being the cerebral hemispheres in terms of clinical relevance there are different types of tumors which would affect or commonly affect supra versus inferential. So, in terms of describing likely pathology, that can be a useful way to think about things. And I'll just show you the diagram on the next slide because I think it explains where exactly we find the dura venous sinuses. So if you think that you've got your dura and it actually is formed to sub layers if you will. So periosteal or endosteal layer and a meningeal layer, if you see, um I'm moving my mouse along and then they sort of split off. And where you find the venous sinus is between those two layers of Jura. It's not between Jura and Arachnoid or Arachnoid. It's between two layers of the Jura itself. Here. We also have demonstrated quite nicely the Arachnoid granulations which project into the venous sinuses. And I'll explain those once when we're having a chat about the CSF spaces of the brain shortly. And this diagram also demonstrates um supratentorial and infratentorial and we can see the tentorium cerebelli highlighted there in red. And that just helps us visualize those two compartments as it were. I'm sure you've all seen this before or if you've not. Um you will, if you're sitting finals the next couple of years and this is the circle of Willis. Um And it's basically a, a diagrammatic representation of the arterial supply to the brain. Um We can work our way up and we've got our two vertebral arteries and they combine in the midline to form a single basilar artery. If we follow the branches of that, we've got the anterior spinal artery and the posterior inferior cerebellar arteries branching off each vertebral artery before they join following the basilar artery up. Uh We've got two anterior inferior cerebellar arteries and then a smaller labyrinthine or internal auditory artery coming off that from the basilar artery, you have multiple branches to the palms. And then following that, the next most significant branch would be the superior cerebellar artery. So just make a note, there's one superior cerebellar artery, but we've got an anterior and a posterior inferior cerebellar artery. And also when you're describing your arteries, make sure that you've got your cerebellar and your cerebral arteries clear in your mind because it's easy to slip those up and um forget which one you're talking about because they are all named quite similarly. But if you learn, learn this and think about it in a systematic way, it helps you to understand um the pathologies that you can see in terms of vascular events which can affect the the brain. Following on. From that, we've got our posterior cerebral arteries and um branching off from that we've got, this is really the main part of the circle of Willis. We've got the posterior communicating arteries, they move forward and join with the um internal carotid artery and the two main branches of those would be the middle cerebral artery and the anterior cerebral arteries coming off from those who've got the anterior communicating artery in the middle. And that's clinically relevant because it is a common site of aneurysm formation. Um I won't go into this in much more detail tonight, but it's really essential to know if you're thinking about any kind of brain pathology. And it's also quite a high yield topic on exam. So worth worth committing the major branches to memory and having an understanding of what they supply so that you can then look back and work out what the deficit would be for any lesions, affecting the arterial supply. So, moving on from that, we'll have a chat about the CSF spaces. Um So CSF is an ultra filtrate of the blood. It's made in the choroid plexus, which you can see is highlighted here in the diagram and purple and that's in the lateral and third ventricles and also in the fourth ventricle, the CSF circulates lateral ventricles, the 3rd, 3rd to fourth and then from the fourth, it can go through the Foramina Luka and Madi. And that is the entire cerebellum and cerebrum and spinal cord in, in CSF. And eventually that is reabsorbed by the Arachnoid granulations that we were talking about earlier. So there are projections which allow the reabsorption of CSF into the venous sinuses where it's then drained away. This is a question for anyone who wants to have a guest. Do we know how much CSF is made by the Arachnoid granulations in a day, doesn't it uh help you at all? That's right. So, from, from our audience in person, we've got the correct answer, which is half a liter of 500 mils per day. And the circulating volume of CSF is about 2 to 300 mils. So it's replaced twice over approximately each day. This is an important principle in neurosurgery and I don't know if you're familiar with it. And the Munro Kelly Doctrine, it's named after two Scottish surgeons who came up with it. And really, it's a principle that describes that the skull is a fixed box with non compressible content. So it's got brain blood and CSF, if you have an increase in the volume of any one of those components, the the pressure will rise and there can be compensation. So if you think that you've got a space occupying lesion in the brain, so there's a volume associated with that and as the volume of that lesion increases, something has to give because it's a fixed container. So the CSF volume can decrease up to a point, the volume of blood. So the volume in the generally, the venous system can decrease, but there comes a point where no more blood or CSF can be pushed out from this fixed box. And that's when you start to get decompensation, the ICP starts to rise and um you'll get eventually herniation and coning at, at the endpoint if, if there's no relief of that pressure. Another question, um, does anyone know roughly what a normal ICP would be, feel free to answer in the chat if you're watching online or we can ask our audience in person? Is it the same as the normal CSF pressure? Yeah. So that's like 15 centimeters. Yeah. So I would say on average it's about 10 and definitely greater than 20 would be abnormal. ICP is affected by things like um BMI and body habits as well. So what's normal for one person might not be normal for another? But we can definitely say that over 20 is abnormal. I've seen between seven and 15 quoted as normal. I take 10 as an average. But over 20 you're starting to say that something is definitely wrong. And that's just to reiterate what I said, the brain can compensate by squeezing out CSF in blood, but eventually you can't get rid of any more. And there's an exponential rise in ICP. And that's when you start to see those effects of raised pressure, like herniation and coning, which describes um the descent of the brainstem through the forearm and magnum and that's generally incompatible with life. So that is a whiz through some basic neuroanatomy, hopefully revision for most of you and the Monro Kelly doctrine, which is a really essential principle to understanding neurosurgical pathology. That's a diagram demonstrating that. So we can see in the case of someone who's had an intracranial bleed in the first um image, we've got brain CSF and blood. But when the volume of blood increases, the volume of CSF has to decrease and that will compensate up to a point and then eventually it's the brain tissue that will be forced out through the path of least resistance and that will have devastating effects for the patient. So a lot of what we do in neurosurgery is trying to manage pressure and manage the effects of that pressure on the brain. Any questions or are we OK to move on to the first case? Happy enough. No questions at the moment. So we'll crack on. This is the first case. So you've got a 74 year old man. He's been brought to Ed with a two week history of confusion and unsteadiness. What would we like to know about this man? Um Thinking about it from a neurosurgery point of view, but also more broadly, um what might be going on? So we'll, we'll chat through, we've got our history of presenting complaint. So he's been increasingly frail in the past year. He says he's had a few falls but doesn't think that he's hit his head and his daughter who's there with him says that she's never seen him to have any seizure activity in terms of past medical history. He's got Parkinson's benign prosthetic hyperplasia, osteoarthritis and he's had an aortic valve replacement he's on COC dopa for the Parkinson's disease, tamsulosin and takes warfarin for his metallic valve. He lives alone. Sorry, walks with a stick and his daughter lives nearby. Is there anything else you would like to know about this patient from the history? So, if we start maybe with some common symptoms in neurosurgery, um Do we think the patients had any headaches, any visual disturbances? Has he found that he, he is weaker on one side of the body than another? I think I would probably want to clarify what exactly is meant by unsteadiness. Um Is it that he's losing his balance? He feels dizzy or is it actually that he goes to stand up and his right leg is very weak and doesn't support his weight and talking about the confusion, I think it's really important to get a collateral history. So if his daughter's there, is he completely disorientated to place and time and this has been quite a sudden change or actually, has it been over the past year that he's more confused and that we can't really relate this confusion to the falls that he's had in terms of the past medical history? I think you'd want to know a bit about his Parkinson's. How long has he had that and how that affects his mobility generally. And um talking about the valve replacement as well, anticoagulation is a massive topic and you want to know why he's on Warfarin. Um What his therapeutic target would be. And when was the last dose? Because for any patient that you see, you need to go in with the mindset that they might need an operation and you need to know that before you can go any further, the social history is useful to know. He lives alone. What was his baseline? He uses a stick. Um, and that we'll talk about that a bit later on when you're having that discussion about surgery and someone's functional baseline and the risks versus benefits of, of undertaking an operation. Moving on then, um, we'll talk about examination. So this is an older, older person. He's 74 and he's had a few falls. So I don't think if you were to meet this man in Ed that you would be wrong to do an ada assessment, he might have other injuries that haven't been picked up, especially if he's been confused. And just because we're thinking about something in the head doesn't mean that there's no trauma elsewhere. So a full a assessment and if any other findings are positive involve the relevant specialties thinking about neurosurgery. However, we are gonna want to do a neuro exam that can be either quite focused if you're fairly confident with what's going on. But I think best at kind of F one F two level to start really broad and that's your standard neuro exam, tone par coordination and reflexes and don't forget the cranial nerves. Um No one ever want to do it, it is quite involved. But actually, if someone's been in for a few days and no one picked up the facial droop and actually they've had an ischemic event. You can miss a lot if you're not thorough. And oftentimes when people come in with one big main diagnosis, other smaller things can be overlooked. So I would say be systematic work your way through the cranial nerves, especially the eye exam. Um and always include examination of pupils and uh a Glasgow coma scale for the patient. So we say for this patient, um he is um weaker on the left, he's got a par of four out of five in the left upper limb and three out of five in the left lower limb. Um but no other signs of injury and his pupils are equal and reactive to light. I think as a baseline, um we should get some bloods for this chap um full blood count CRP LFT S we know that he's on Warfarin. So we need to get a clotting screen as well. Absolutely. And if you're fairly confident that the patient is going to need surgery, at that point, you should get your um group and save blood transfusion paperwork completed and get the samples to the lab in case um the patient were to take to deteriorate. You want to make sure you have those as soon as possible before you go any further. So, moving on um we'll talk about G CS. So when you talk to the patient, he opens his eyes. He's quite confused and he's just mumbling words, but he is obeying commands. Do you want to take a moment to think and work out his G CS? And then we'll talk through it in a minute. Anyone in the chat, 13 plus uh 13 and 12 A six, we'll talk through that in a second. So I would say E 3 B3 and M six and we'll, we'll discuss why? So he opened his eyes to voice. So we get E three. He was confused but mumbling words. So I would score him a three for that because he's not speaking in sentences and is confused. He's speaking in words and mumbling in terms of movement six, he's obeying commands. He's been able to cooperate with your investigation or your examination of him. Um And that would give 336 that would give us a score of 12. Um I would say as a more general point whenever you're discussing G CS, unless it's 15 or three, you need to give the breakdown of eyes, voice and movement because there's a big difference between someone who's scoring, say one in eyes, but fully in all the other ones versus someone who's scoring a reduced number in each section. And any neurosurgeon if you say G CS 12 will say why? What, what's the breakdown? So the most value valuable information you can give is, and M rather than giving the total of the G CS, um just talking through what people score for. So, eyes spontaneously. So that's normal if they opened a voice, but they're a bit sleepy three, if they're only opening to painful stimulus and you're really having to work to get the person to open their eyes, that's a two. And if you cannot get any meaningful response, that's one for someone who's conversant and orientated to place and time. They get five for voice. For a lot of the older people we see they would score of four. So they're confused. They maybe know that they're in hospital but they don't know where or why or they don't know in the hospital, they think they're on a boat, but actually they're able to have a conversation with you. They're just confused for this chap. I've said three because he's mumbling words, but he's not really having a conversation with us, but he, he's doing more than two, which is just making sounds and one is no verbal response at all. You need to bear in mind that sometimes patients aren't able to give a verbal response. So for example, if they've got a tracheostomy without a speaking valve, they're not going to be able. So they would automatically not score for voice. So what, what I've seen is that people just put at for tr I'm not sure if that's standard in, in all places but it gets the message across finally talking about movement. So six obeys commands. And even if the person is not able to respond verbally, if you ask them to do something and they do it, you know that they've understood you five is localizing to pain. And you can see that best if you have a painful stimulus above the clavicle, and you can see that the person raises their arm above the clavicle. So for example, the supraorbital pressure, um four is a flexion withdrawal from the pain. So actually the person might move their upper limb away from the pain rather than towards it. Three is an abnormal flexion response. Two is abnormal extension and one is no response at all. So GCS of three is the lowest score you can get, it's not possible to get a score of zero. And um as I said before and just to reiterate it always give the breakdown of, of why someone is scoring. The next thing I wanted to talk about is your examination and it's describing the grade of power or the grade of weakness really that you get on examination. So this person I said was four out of five power in the upper limb and 35 in the lower limb. That's me being a bit lazy because really when you examine someone, you should describe each of the movements, you've got your shoulder abduction, elbow flexion, extension, wrist flexion and extension and your digital abduction and then for the legs, you've got your hip flexion, extension, knee flexion, extension, dorsiflexion and plantar flexion. And it's often forgotten. But um extension and flexion of the big toe actually can be quite specific for lesions at certain levels of the spinal cord. So, um it is important to be thorough and it means that your colleagues who then go and review this patient in the middle of the night, know exactly what they look like when, when they first came in. So just to talk through them, five is normal power. And that's what you would expect from someone fit and healthy. A lot of the time, if your patient is bigger than you, they will be stronger than you. And if it's a little old lady who's got sarcopenia, she probably won't be as strong as you. But basically, it's normal power that they're as strong as you expect and they're able to move against gravity and resist your movements, which are countering them. Four is slightly reduced. So they've got active movement against gravity and resistance, but it's just not quite as strong as you would expect. This can be quite subjective and I know some places will talk about four plus and four minus. But I think really, it's just that the person has power, but it's not what you were expecting and it's not what would be normal for them. And that's where it's important to think about the patient. Three active movement against gravity, but they're not able to resist you. So that's a big difference between three and four and then two is where they're able to move, but only with gravity eliminated. So they're not able, for example, to flex their elbow. But if you put it on a table and take away gravity, they're able to move it back and forth. One is that there's just a flicker of muscle movement, the smallest trace of a contraction but no meaningful active movement and zero is just when you see nothing at all. So really important to understand what each of those mean when you're examining a patient and if you're not sure, um don't be afraid to reexamine them and sometimes pain can limit patients as well. So someone might see that it's a two or a three, but actually with some good analgesia, they're able to be examined more fully and and are actually a four or five. The next thing that I wanted to highlight with this case is that the patient is on Warfarin. So perhaps jumping ahead a bit. But if we're saying that this patient needs neurosurgery, he had his last dose of Warfarin that evening before he presented to any, what do we need to do. And so in the first instance, you stop the Warfarin, make sure he doesn't get any further doses. And you start by giving IV Vitamin K I've seen five or 10 mgs and this is just the protocol I picked because I think it talks through the stats quite clearly, but obviously check with your local protocol. Vitamin K is given because Warfarin is a Vitamin K antagonist and it helps to um replenish some of the clotting factors which are inhibited by Warfarin. But actually, it takes about 24 hours to have its full effect in reversing Warfarin. So if you need to take someone to theater immediately, you're more likely to have to give intravenous growth orbin complex concentrate. And that has a few different brand names. But Beriplex is probably pretty well known how much Beriplex you give is dependent on how high the inr is and also um the size of your patient. So it'll be a different dose, I think for most places I've worked, you need to order that from blood. Um they'll reconstitute it for you and deliver it to the ward and then the nurses are able to give it according to local protocol and then check the inr after that and make sure it's um below what, what local guidelines need it to be for surgery, I think for neurosurgery, it's generally less than 1.4 or 1.2. Um but I'm not sure about other surgical specialties specifically. So, moving on, we've got our bloods and our imaging um for this patient. Does anyone know what type of imaging modality we're looking at? Yeah. So it's a plain CT head and if we were to talk through the scan in terms of the findings. There are a few different things but, um, would anyone be able to comment on the most obvious abnormality? Pardon, the midline shift? Yeah. So we've got the midline shift, what's causing the midline shift? There seems to be something there like on the side that looks a bit crescent. That's right. So, I don't know if we've had any answers online, but so, yeah, we've got what has rightly been described as a crescent shaped lesion left or right. Right. Yeah. So it's right-sided present lesion. And how would you describe the density of that? It's hyper hyper. Yeah, absolutely. So do you know if this was an acute bleed, would it be hypo or hyper? So, what we're talking about is a crescent shaped lesion with mixed hypo and hyper density, new blood, acute blood is hyperdense and old blood is hypodense. So actually here, what we can see is that as the patient has been laid supine for the ct head, the more dense acute blood has settled to the bottom and we can always see a gradient as it moves up to the hypodense chronic blood. If we think back to the history from this patient, he said he's had multiple falls but doesn't think he's hit his head. So I think what we have here is probably an acute on chronic subdural hemorrhage or subdural hematoma. And if we look at the, the midline and the ventricles, we can see that there's been shift from the right to the left and that's due to the mass effect caused by the subdural hemorrhage. Um If you had the images up, you could measure the degree of midline shift to quantify it. Um but this is just a, a picture. So we're not able to do that. You can have a look at the ventricles. And if you had the full um ct you could see if there was any evidence of hydrocephalus or any other intracranial pathologies just because someone has a subdural, doesn't mean they don't also have um any contusions or they might have a subdural hemorrhage on the other side as well. So it's always really important to look through your images thoroughly and not just stop when you find something wrong because you might miss other things that are wrong. Um I think when we talk about intracranial bleeds, people always like to compare. So what we are talking about in this case is a subdural hematoma. And if you think back that's in that space underneath the dura matter, but not within the arachnoid matter. The bleed comes from bridging, cortical veins and there are certain populations are more susceptible to subdural bleeds because of cerebral atrophy. It means that there's more space and that the veins are more vulnerable to um sharing forces which causes the bleeding. They, these can be unilateral or bilateral. And actually, if someone is quite frail and vulnerable and has been having multiple falls on anticoagulation. It's not uncommon to have bilateral subdural hematomas. Generally, the history is more insidious. So gradually increasing headache confusion, some weakness and maybe some sensory disturbance, but it's unlikely to have come on. It can. But in generally, in older people, it's a longer history. Um there's generally not any fractures associated with this. And if you look at the pattern of the blood, the reason we get the present shape is because it's limited by the dural folds and venous sinuses because it's in that subdural space. So that's what I was trying to say earlier. If you understand the spaces and what limits them, you can understand what you're looking at on the scans. We could see quite nicely in the CT, we looked at it had a crescent shape and um in terms of the onward management, we'll talk about that shortly, but it depends on the presentation and it depends on the patient. Just as a point of comparison, we'll look at the extradural hematoma. So that's an arterial bleed. And it, it's classically from the middle meningeal artery which underlies the pterion and that's the point of weakness in the skull. So it's quite vulnerable. You might have um heard of kind of one punch injuries and generally the middle meningeal artery because it's underneath quite a thin section of bone is vulnerable to damage and to, to hemorrhage in this pattern. So that's generally unilateral. The patient has a lucid interval and then a sudden loss of consciousness rather than this gradual history. And often there are associated fractures because this is extra dural. It's limited by the cranial sutures rather than by the dural folds. And it often has a biconvex shape. Sometimes people compare the extradural to a lemon and the subdural to a banana. Um These almost always need surgical drainage that happen much less commonly than subdural hematomas. I would say. So, talking about our patient, he's 74 he came in with a gradual history of unsteadiness and confusion. He's got Parkinson's osteoarthritis and he has a metallic valve and is on warfarin performance status was pretty good. He was living independently and walking with a stick. Um So you need to think about all of these things before you consider whether this patient is a good operative candidate. And also if the patient has ever expressed any prior wishes, I would say in this case, it would be reasonable to um consent. This man for surgery, he's had a short history, two weeks of confusion. He had a good performance status as his baseline and we able to reverse his anticoagulation and really the weakness and confusion are likely to be resolved by relief of that pressure. But if the patient had any strong wishes for or against surgery, obviously, you would take those into consideration and sometimes a watch and wait approach is more appropriate there are many people walking around with subdural hematomas who don't know that they have them and don't have any symptoms. So if they're not causing mass effect, or if the patient has a very, very poor functional baseline, and you think that the risks of surgery would outweigh any benefits from draining the subdural hematoma, then it might not be appropriate to operate. In that case here, I've just got what I thought was quite a nice image to bar hole drainage. Um Generally a subdural will be drained either via bar holes like you can see here or a mini craniotomy. And that's if the bleeding is more extensive or if um significant membranes have formed and those are kind of fibrous septations which form in more acute, more chronic, sorry, more chronic subdurals and can make it more difficult to fully drain the blood. So you can see here. Um We've got two bar holes and there's generally normal saline being used to irrigate um through the superior one and to drain the blood out of the inferior one. And you, you do that until the blood has cleared. And in a lot of centers including where I work, they'll leave a subdural drain for about 48 hours postoperatively to continue to allow any blood to drain. Another interesting point is that increasingly interventional radiology are involved too and they can embolize the middle meningeal artery and that significantly reduces the risk of reaccumulation. Um It's an evolving area and there's a lot of research into it at the moment. But often for more frail patients that their risk of reaccumulation are higher and they're less likely to recover from a second assault to the brain if it does reaccumulate. So you might think about middle meningeal artery embolization and in a subdural. So does the do we just hope that the bleed will stop? You are likely to have another? So it can reaccumulate because you haven't stopped where the bleeding is coming from. But generally, these are chronic and actually the symptoms are caused by the accumulation over time and the pressure effects. So, if you have someone who is quite frail to begin with, they're less likely to bounce back if it reaccumulates because it's a second assault to an already vulnerable brain. And for most people washing it out is sufficient and there might be some ooze, but it should settle down. That's one of the reasons we leave the subdural drains in and also everyone gets a POSTOP ct of 48 hours to make sure that there's been no reaccumulation. I think generally it's quoted as a risk of about 20 to 30% of reaccumulation. But it doesn't necessarily mean that the pre they will present the same way they did the first time. It might be a small subdural, but then cells and it's reabsorbed over time. It doesn't a second subdural hematoma doesn't necessarily mean a second surgery. But for some people who would be more at risk of that, you want to avoid it in the first place. And I think over the next few years, probably the middle meningeal artery embolization will become more and more common alongside verbal drainage and to stop the reaccumulation for wider groups of patients. See, so that's, that's the end of case one. I don't know if you've got any questions in the chapter, Shereen, if you've got any further questions, we go on to the second case then. So like I said, my, I'm currently on tr and orthopedics at Swindon, which is ad GH and doesn't have much of a neurosurgery department which means that all of the back pain cases get referred to us and they're very common. So this is something that we see multiple times on every on call shift. A 48 year old woman presents to Ed with a one week history of back pain radiating down her left leg. Let's give you guys 30 seconds just to think about what other aspects of the history you might think are important and what other questions you might ask and then we'll go through some things that I think are important. OK? Just give me five more seconds. So if we look, look at the next slide, then so in terms of her history of presenting complaint, the pain radiates down the lower back to the left leg and she's got a one week history of this with shooting pain. Uh and it's not been helped by analgesia. Really important to ask whether the pain is unilateral or bilateral. The other thing to ask about is any associated symptoms, particularly symptoms around the bladder, passing urine, passing feces, issues of continence and numbness. So, in, in our lady here, we can see that her associated symptoms, she's having difficulty passing urine, uh and numbness of the buttocks in the past 24 hours. A really good way to ask this question as well to ask about whether they've got numbness is to ask whether they're able to feel when they're wiping. So after they've been to the toilet, are they able to feel when they're wiping? Also important to note the time frame of the uh of the symptoms. So she's had one week history of, of this sciatic type pain shooting down the left leg, but she's had an evolution of that symptom because now she's got these new difficulty passing urine and this numbness in the buttocks for the past 24 hours. And commonly, you see patients who have a, a background of longstanding sciatica who are then coming in with a change of symptom, which has gone on over a short period of time. And that's really important in the management of these, of these presentations overall. In terms of the past medical history, she's got gord, uh she's on omeprazole for that and a social history is that she is a hairdresser and lives with her husband and three kids and she's a smoker of 20 pack years. So with this presentation, then anybody got any ideas of what you're most concerned about in the room. So Cain Syndrome is the thing that you most mostly want to rule out. And like I said, we get referred probably, probably about four of these on it. Almost every ONCO share. So I'd say we get four on average query called a equina. And the most important symptoms that you want to look out for are the bilateral sciatica. So that's sciatica down the back of both legs and really important to distinguish that it is true sciatica. So oftentimes particularly in the older population, you'll say, do you have pains in your legs is the pain radiating from the back of the legs and they'll go. Yes, I've got loads of back pain. The sciatic symptoms are that shooting pain, that neuropathic pain that's radiating down the back of the leg and down the whole leg. So, if they just have pain in the anterior thigh, for example, that's obviously not sciatic type symptoms. The saddle shaped anesthesia like that we mentioned before, a really good way to ask about that. Uh is, can you feel when you're wiping? Have you noticed any change in the sensation when you're wiping? Um, because often times people don't test that themselves. So that's a really good way to make them, think about that and any urinary retention with overflow incontinence uh is also an important thing to ask about. So, are they having difficulty starting to urinate? Do they have any pain suprapubicly or are they suffering with any incontinence? Um which might be due to retention. Um Also worth mentioning that fecal incontinence is a sort of soft sign for corda, quina. So often times people will present with some level of fecal incontinence as well. Uh But urinary retention is a, is a more of a red flag symptom on examination then. So you note that the tone is normal, their power is three out of five in plantar flection, er which is S one and S two and hip extension er as well. Coordination is normal extension, normal uh coordination is normal and OK. Uh and the reflexes are reduced. So she's got reduced ankle, just re reflex on the left. Also worth noting that as, as well as um doing this, you, you can also think that you've done a bladder scan and that she has got some urinary retention on that as well. OK. Question then what L level do you think the lesion is likely to be given these symptoms? Just give you 10 seconds to think about that this room, I guess from the to is there S3 as well? There is, there is a three, there is ray but so I think it's most likely going to be uh L5 S one. So when you, so the most common cause of, of uh Corre syndrome is a disc prolapse. And that's, that's the thing that you see most commonly. Um, just to the side point, can you think of any other causes of quina? Yeah. Trauma, trauma. Perfect. Yeah. So you can also get infective causes. So we had a patient here who had uh TB so pots, um, and that caused her to have cord recliner, which she had to have surgery on uh discitis can sometimes present with cor a recliner. Um hematomas, particularly if people have had spinal operations and they can get POSTOP hematomas. We had one this week actually who have called quina with a subdural bleed after having an epidural. Um But by far, the most common presentation is people with a, with a disc prolapse. Um We saw in our person that they've got 3 L5 power and panta flexion, which is S one S two and hip extension. So L5 S one S two. Uh So it's gonna be somewhere around those nerve roots that are implicated. Generally speaking, the disc prolapse affects the nerve root below the vertebrae. So if we think L5 S one, then that s one which is transversing past that vertebrae is gonna be affected by that prolapse as are all the other nerves going past it. The reason that it wouldn't be further down is just normally it's the lumbar region that the prolapse actually happens. So somewhere between, you know, L2 to s one more commonly than a prolapse happening in the, in the sacral region. OK. So if we look at the MRI of our patient, then um any idea what type of image we've got here? Two. Yeah. Perfect. T two. T two MRI. And how do you know it's T two or what makes sure you think it's T two. It's the colors that we the black one. It's the one. Yeah, exactly. So the way I've always remembered it is that uh T two highlights H2O so T two highlights the fluid structure. So this light section that you can see going down the spinal cord is your CSF, which is the fluid and then you can see at the back the more darker lipid covered, uh nerves are shown as well and they're darker on this MRI. You can see here around L5 S one. You've got a complete black out of your CSF. So there's a compression, a prolapse of this disc which has caused the complete um movement of the CSF. So it's completely blocked off. And therefore you can assume that the nerve roots as well are completely blocked on this side. It's, it's harder to see where the spinal cord normally should be. But normally there's a nice ring of CSF uh in this sort of region and you can just see little dots which are those transversing nerve roots going down. Uh but here because of that compression, all of that CSF has been displaced and there's compression of those nerve roots. Ok. Um In terms of management of these patients then, so it's an emergency surgery. Um And the reason for that is that patients who have that compression uh for a long period of time, particularly if those symptoms have come on quickly like they have in our patients. So over the past 24 hours, um you can get uh definitely those nerve roots. So long term patients can struggle with incontinence. Uh And that's sort of the main reason that you want this to happen as quickly as possible. Um And the quicker the the surgery happens, the more likely they are to retain continence in the long term. Uh And the surgery for that is a lumbar decompression, which is usually a laminectomy and discectomy. What exactly the surgery is obviously varies depending on what's actually causing the presentation. So, ca Aqui syndrome is more a sort of classic symptoms that people present with. Um But usually it's gonna be that disc prolapse in which case you would do a laminectomy and a discectomy and just to kind of highlight what that looks like. So your lamina is the seal vertebrae that connects the pedicle. So the pedicle going from the vertebral body to the transverse process and then the lamina going from the transverse process to the spinus process and the laminectomy is the removal of that section of the vertebrae and then the movement of the er transversing nerve nerve roots out of the way, which then allows the surgeon to come in and do a discectomy, which is the removal of all that nucleus er pulps which has gone through the annulus disc um to therefore sort of decompress that area um and allow that, that CSF to move back in, in the spinal cord to sort of breathe nicely again. Ok. Does anybody appreciate that was sort of a whizz through with called a recliner and things that sort of investigations that you want to do initially? Has anybody got any questions on that before I hand back over to Emily? Nothing in the chart that you want? Yeah, I, I'm back. She's gonna talk to you about evds. This will be a quick chat about evds, um, external ventricular drains. Um, they has any, has anyone heard of an E VD or has seen one before? Um. Yeah. Yeah. CP patients. I don't know if it's the same thing past some medicine where they've got, um, is that the same thing slightly different? And we'll have a chat about that. So EBD, external ventricular drain, its name really describes what it does. So it's a drain which is inserted into the ventricles. So the CSF spaces and drains CSF to the outside, diverting it from the normal circulation of CSF around the brain. It drains the CSF using gravity and we'll talk a bit more about how the drain itself is set up in a moment. But can anyone online or anyone in the room think of any indications for draining someone's CSF? Yeah. And cough. Yeah. Anything else got infection? Yeah. And bleeding. So, Hydrocephalus described build up of CSF, um, CNS infection. So we can take samples of CSF and give intrathecal. So, antibiotics into the ventricles through an EBD and also in the um period after trauma or after um a surgery where it's been bleeding into the ventricles. Um, bleeding into the ventricles can cause um a communicating hydrocephalus where the blood basically bumps up the um passage of CSF and then the CSF builds up causing hydrocephalus. It's also a very good way to look at CSF drainage and see the progress of that. So if it's someone who's had a bleed, we can see the blood stain flu clearing. Um And if it's someone with hydrocephalus, we can see um whether long term they might need a shunt, uh a ventriculoperitoneal shunt to manage their excess CSF. So this is a picture of a pretty standard set up for an EBD and we can see this is the catheter. Um So it's generally inserted under G A sometimes using neuronavigation into the lateral ventricles, it's brought outside and tunneled a short distance and that's really just to keep it secure and to mean that it infection is less likely to track along it and get directly into the ventricles. But also in terms of repositioning the patient, it's less likely to be pulled out accidentally. We follow the drain along and we can see here, we've got a three way stopcock and that's to give you access to the ventricles and to allow you to give those intrathecal antibiotics or take CSF samples. And we'll talk a little bit about how this works on the next, on a future slide because it takes a while to think about which tube connects to where and where you want. If you're taking a sample off or putting something in where exactly you want it to go. If you follow that round, then we've got a further stopcock here and this is where we zero the measurement for the EVD. So we said that the CSF drains by gravity and that's generally, um, pressure measured in centimeters of water. So a lot of them have a laser or a spirit level and you want to zero it uh to the tragus of the ear. So if you follow that back, this one is at zero, but this stopcock here, you can adjust the height of it. So if you want it five centimeters of water, you physically take this bit and move it further up the scale. And that means that in order for the CSF to drain, the pressure would need to be up above five centimeters of water. I'm not sure if all EBD S use the same units of pressure. But that's what I've seen. Follow this um distal catheter around. Then you can see that it connects to your chamber. And nursing staff will generally allow this to fill up over an hour, take a recording and then empty it into the collection bag. And that's how closely you have to keep an eye on the CSF drainage in these patients. So the pressure is adjusted using the scale. And anytime a patient needs to move position, you need to clamp the drain because the change in position of the patient changes their ICP and ICP is different if you're lying down or standing up. So if the patient needs to move or for example, in a child, if they were crying, that would raise their ICP, so you need to clamp the EVD and ensure that ensure it doesn't drain excessively um over drainage of CSF can cause low pressure headaches. And generally patients feel quite unwell with those. But if they are able to lie flat and not have excessive drainage, they can recover quite quickly. What we want to see a lot of the time with the EBD is, does the patient rely on this in order to manage their CSF? So as we saw with the diagram, you can move the EBD up to 5, 1015, 20 and you gradually raise this over the course of a few days. Um And you really clinically look at how the patient is. If there's any drop in GCS headaches, visual disturbances, you get a CT scan. And if you can see on that CT scan, that there's been an increase in the size of the ventricles, you know that this person will need a way of draining CSF, that's not through the normal anatomical mechanisms. So um that would be the point at which you think of a VP shunt. The reason you don't go in with a shunt in the first place is you don't know that everyone needs a shunt, say after trauma. And also there's a much greater risk of infection. So if the shunt becomes blocked with blood, it's not going to work and they'll need another shunt, which is a much more invasive procedure than an EVD. Not everyone will need a shunt. And also in terms of infection, if someone has a shunt put in whilst they have active CNS infection, the shunt will become colonized and infected and will need removed. So the EVD allows us to manage that period where they're acutely unwell. And then also see if they'll need longer term CSF diversion. I think my final point then is talking about a blocked DVD and this is something we get bleeped about at least one or two times a shift. Um In the first instance, you ask some of the basic questions. So where is the EBD? When did you last? See it draining? What does the fluid look like, but probably you're going to have to go and see this patient and have a look at the EVD for yourself. If we think about how an EVD works, it drains CSF using gravity. So if we lower it to the ground, that's decreased the pressure into the negative compared to where our zero point is. So actually, if the drain is patent, the CSF should flow if you'd lower it to the ground. And that's a way of saying that it's not draining because the pressure is not raised rather than because it's blocked. The next thing I would say is to flush the distal catheter. And that's um, generally just with normalcy of line, sometimes debris from infection or blood can block the catheter. And if you're able to flush that, and then all of a sudden you see CSF draining, you know that, that solved the problem flushing the proximal catheter. So that's the part which goes directly into the ventricle that's more invasive. And you would have done all of the other options before you flush that because actually if you're pushing normal saline in, but it has no way out, you risk increasing the ICP. But it is something that we do with small volumes of saline to see that is the catheter patent or not. And if you've done all of those things and the E VD is blocked, the patient needs to go back to theater and have another E VD put in, I think my final slide here is just talking about the three way stopcock because it takes a little bit of thinking and you need to make sure your antibiotics aren't going to your distal catheter. And, um, everything is where it should be. So the ones I've seen generally look like this, they've got an off port and then three open ports. Sometimes they look like this and the off part port isn't marked or they look like this and they've got an off port that's marked and all of the other ones aren't, which is a bit confusing. But before you start any procedure accessing an E VD, make sure you know which one is your off port because in the middle of a procedure is not the time to find that out. I thought this was quite a nice diagram and it shows you if we say that A is the proximal catheter go into the patient. C is the distal catheter and B is where we're able to either take samples or give antibiotics. If you have your off tap, turned to C, then you can give your antibiotics from B to A or you can take your sample from A to B, making sure obviously that you turn it off afterwards. If you're not giving anything, uh not giving any antibiotics or taking any samples, you don't want B to be open because their CSF will just pour out. So you turn the stopcock. So off is B and you want it to go from A to C and it doesn't matter actually, if there's one that's open here because there's no port for it to go through. Finally, we've got a, the off is at the A position. So that's means that the proximal catheter is off and you've got access from B to C. So that's where you'd want to flush your distal catheter and understanding how this works and what it looks like, I think really helps you feel confident when you're doing these procedures because you know, you're accessing the right space with the right intervention. So that's everything I wanted to say on EBD S um apologies if we've overrun a bit. Um But our learning objectives were to know basic neuroanatomy and neurosurgical principles to understand history, examination, investigation and initial management of two neurosurgical emergencies and to have a basic understanding of the management of external ventricular drains. I hope we've covered that and let me know in the chat or in the room if you've got any questions flushing the catheter. So that's what you would try after lower. That's right. So the question, sorry for anyone online was, is this image we see where you would flush the distal catheter? And that's right. So if you've got B and C open, you can flush normal saline through and see is the distal catheter. So all you're doing is introducing normal saline and trying to see if that encourages drainage of the CSF, once you then rotate back to the ac position, any questions online? I don't think so fine. Um So this is our last session out of the six for screws scalpels and suspicious. Um Thank you to everyone who's joined in person and online. Um We've learned a lot from doing it. Thank you for being patient with the technical difficulties and we hope you found it useful and keep an eye out. Um We have a few future sessions that might come about in the next couple of months or in the new year. And if you wouldn't mind completing the feedback forms, it's really important to us to find out what everyone's thought and that'll help us improve for any future sessions. But thank you very much. Thank you very much. Thank you for coming.