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ESSSxAIM presents: An Operative Approach to Anatomy - Neurosurgery Part 1

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Want to learn more about anatomy and its theatrical (by which we mean surgical) applications, but don’t know where to start? Watch the ESSS and AIM: An Operative Approach to Anatomy! This is the fifth webinar of eight and will serve as an introduction to the theatre and some of the key anatomy to look out for when observing (or assisting) in Neurosurgery.

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The following transcript was generated automatically from the content and has not been checked or corrected manually.

Welcome everyone. I'm Jing Jing. I'm 1/5 year medical student at the University of Edinburgh and these are my colleagues, Jane Clare Su and Anton also year five medical students today. On behalf of the Edinburgh Student Surgical Society and accessibility in medicine, we're gonna be teaching the fifth part of the Pure L series, an operative approach to anatomy, focusing on neurosurgery, just some housekeeping. Uh Before we begin, I'm sure you'll be very familiar with this if you've already attended our previous sessions, but we're gonna answer questions via the chat and the session will be recorded and the slides will be made available via meal. Please be aware that the slides contain pictures of surgeries. So if you're not comfortable with that, please do turn away and please note that we will be sending out some polls to collect some data. And these are completely anonymous and really helpful for uh letting us know whether or not our teaching is effective. So please do fill everything in. Uh attendees of six out of eight sessions will get free R CS student affiliate membership and do follow the E SSS and Ames Med all and social media to see all our future events, just a disclaimer that this is a peer tutorial, uh and it's led by medical students and although we've tried our best to make sure the information we're teaching is up to date and accurate, there may be some mistakes. So do forgive us. Please also know that all media shown is not owned by us and will be credited on slides when it's not credited. They're likely to come from complete anatomy, which is a great anatomy resource for your own revisions before we begin, uh, please do fill up these quick polls which will help us to see if our teaching is effective. I'm gonna send them out into the chat. There are six poles in total and you can open and close polls and you can find all the polls in the messages section and please fill them all in because they're super, super helpful in letting us know how you guys are finding our teaching and will just give us about two minutes so everyone can answer all of the polls. Please do scroll up in the chat where you'll see all six poles and all six. Please. Please do answer them. You'll get a brownie point. Yep, these sessions will be recorded and the slides and the recording will be made available via meal. For those of you who have just joined. Please do fill out the polls on the chat. There are six of them and they're just helping us figure out whether or not our teaching is effective. Thanks everyone fab Right. That should be enough answers. But if anyone does want to answer the polls, now, please, please still do. But I'm gonna carry on for time's sake. So, uh, to start off with, uh, neurosurgery is often regarded as perhaps the most complex and the most scary of the surgical specialties. But it's really important as medical students for us to understand the anatomy to gain the most out of observing surgery, especially during surgical placements. Today, we'll be bringing you through three neurosurgery cases featuring craniotomy, transsphenoidal resection and spinal decompression where you'll learn a bit about the relevant pathophysiology, anatomy, clinical features, investigations, management and complications. We'll then get you all to interact with a simulated case and follows us the session up with some MC Qs to basically check that you were listening. No previous understanding of surgery is required as this will be built on throughout the tutorial and all the poll and MC Qs are anonymous. So please don't be shy if you're not sure a guess is always better than nothing. So to start off, uh what do neurosurgeons do? Well, neurosurgeons, diagnose uh A SS and perform surgery on disorders affecting the central nervous system. So the brain and the spinal cord as well as the peripheral nervous system. There's so many subspecialties and training is eight years long following fy, you don't need to do core surgical training to get a neurosurgery post as it's a run through specialty. But keep in mind, it is a very competitive. In 2020 there were 220 applications for 26 specialty training places, neurosurgeons undertake operations for a wide wide range of conditions including the cases we're gonna look at today. This is a sort of nonexhaustive uh list and you can find out more about the specialty through resources like teach me surgery, the Royal College of Surgeons and your local and national Neuros societies, for example, NA MS I, to start off with our first case, we're gonna talk about craniotomies. We'll briefly touch on what a craniotomy is, its indications and some of the pathophysiology around intracranial hematomas before we get to the juicy part of the section, which is the anatomy and the interactive case craniotomies are as you expect the creation and temporary removal of a bone flap from the cranium to access the intracranial compartment. And this is usually for doing things like removing tumors for a, a diagnosis or treatment or for evacuating intracranial hematomas. We're gonna concentrate on the second of these indications for the sake of our case, for those of you wanting to do a diy craniotomy, which I obviously do not support. It basically goes like this. Uh The patient will be put under general anesthesia and they will usually be given dexamethasone er to sort of preoperatively reduce cerebral edema if they're removing something like a tumor. They might use a procedure called neuronavigation, which is the use of a computer software to basically map pre op imaging to the patient's head in theater. So it sort of is used to guide the surgery. The scalp is then incised, uh and reflected off the cranium just like in this image. Let me get my pointer up. Sort of like, uh when you peel off the lid of a yogurt pot, it's sort of that. It's not like fully resected off. It's sort of pulled back essentially. Then bur holes are fashioned in the skull. So those, those are those little holes there. And then uh a craniotome which is attached to a pneumatic drill is used to basically uh cut here connecting the bur holes. So you can take that flap off. Stitches are then used to attach the dura to the s uh skull or the soft tissue. And that's basically to prevent an extra dura hematoma from forming. And then the dura is coagulated and opened using a scalpel or scissors to essentially create a flap. Interventions are then performed so that could be your washouts or your sections. And then after hemostasis, everything is closed up and the bone flap is replaced as long as the um brain is not too edematous, the bone flap is then screwed with titanium plates and uh screws and then the scalp is closed. Obviously, this is a massive surgery with lots and lots of potential complications including intracranial hematoma, focal cerebro edema, seizures and even death. So, as you can expect, you've got to weigh out the risks and benefits. If you're going to perform this kind of surgery, if someone's got an uncorrected coagulopathy, which might result in major hemorrhage, or if they have a short life expectancy or poor performance status, that cannot be improved by the surgery, then it's absolutely contraindicated to give them a craniotomy moving on to the next bit. Uh, intracranial hematomas are essentially any bleed within the cranium ak within the skull, depending on the etiology of the hemorrhage. Intracranial hematomas can be classified as primary or secondary. So, primary would be uh for example, due to something like underlying hypertension, while secondary would be uh resulting from a sort of secondary cause like a trauma or a tumor. There's lots of common risk factors for intracranial hemorrhage including increased age, uh being male, excessive alcohol consumption, smoking, illicit drug use and high risk behaviors as well as being on anticoagulative and antiplatelet drug therapy. The clinical presentation basically varies according to the size and the location of the hematoma. However, symptoms can often include signs of raised intracranial pressure, like nausea and vomiting, loss of sensory or motor function, severe headache or alterations in the level of your consciousness, which can be measured via the Glasgow coma scale. And if it's left untreated, it can progress to coma or even death. It's a medical emergency requiring urgent therapy. So initial management focuses on stabilizing the patient as per advanced trauma, life support guidelines and preventing secondary brain injury. For initial investigations. Uh routine urgent bloods like the full blood count using EC RP clotting profiles in a group. And save because you might need to give them a blood transfusion later should be taken. Urgent ct heads are really needed because uh we're needing to source the location of the bleed and know what type of bleed it is. If we suspect, oh, it's, it's likely an aneurysm or an AVM like an arteriovenous malformation. Then we might want to do a cerebral angiography uh to determine the nature of the vascular lesion and locate the source of the bleed. Patients who are on anticoagulant or antiplatelet therapies should have their coagulopathy reversed through administration of the appropriate reversal agent. This is sort of uh something that you might want to discuss with hematology and some of these patients may require surgery and the decision to operate really depends on quite a lot of factors including the patient's neurological condition, the patient's age and functional status and also the size of the craniotomy. Uh I'm sorry, the size of the hematoma. Um patients requiring surgery will often undergo a craniotomy which is the removal of a bone, but replacement of the bone later or craniectomy, which is removal of the bone, but without replacing it after and evacuation of the hematoma and or ligation or cauterization of the source of bleeding will then be undertaken. Some patients might require the insertion of an intracranial pressure monitor device for ongoing monitoring to make sure the pressure isn't building up again and they're getting those symptoms again. Postoperatively, patients are usually observed in neurocritical care or high dependency and they're needing to be monitored very, very regularly and ongoing neurorehabilitation is often required which involves a vast MDT. There are several different types of intracranial hemorrhage, uh including extra duo, as you can see here, sub duro which you can see here, subarachnoid, which you can see here and intraparenchymal or sometimes called intracerebral. I'm gonna talk you through that next. So firstly, we have the extra duo hematoma to the left. Um As you can see, um it's a collection of blood that forms between the inner surface of the skull and the outer layer of the dura. Uh It's usually associated with a history of head trauma and is frequently associated with a skull fracture. The source of bleeding is usually um from a torn middle meningeal artery and it sort of displays on CT as a hyperdense biconvex lesion, which sort of looks like a lemon, which is a nice way to sort of remember that uh if you're trying to identify all the different interest uh cranial hemorrhages because of this lesion, it can cause a mass effect with herniation, which is basically the shift of brain tissue blood or CSF from their normal position inside the skull. And the reason why it's got this sort of lemony shape is due to the bleeding being limited by the firm attachments of the dura to the suture lines on the inner surface of the cranium. Extradural hematomas can be managed conservatively or surgically depending on the number of fibers including size, midline shift and G CS et cetera. Next, we have the subdural hematoma or subd hemorrhage, which is basically a collection of blood accumulating in the subdural space, usually due to stretching or tearing of bridging cortical veins as they cross from the subdural space, strain into an adjacent duro sinus, subdural hematomas are sort of present shaped as you can see here. This one's actually a drained subdural hematoma where you can sort of see where it would have been and it's sort of uh shaped like a banana, which is my way of remembering what uh what shape it is. These are usually more extensive than extra hematoma because they're not um sort of limited by the suture lines. In contrast to an extra hemorrhage, subdural hemorrhage um is limited by dual reflections instead such as the Fox cerebra, the tentorium, the Fox cerebelli et cetera, uh and subdural hematomas will also appear differently on CT imaging. So, uh the extradural hematoma is most likely due to a trauma based, but the subdural ones can be due to a trauma, but they can be acute, subacute or chronic or even acute on chronic. And so they'll display slightly differently because the blood will have sort of formed and, you know, aged, uh depending on the time frame, moving on to subarachnoid hemorrhage. This is basically bleeding into the subarachnoid space. And patients typically present with what's known as a thunderclap headache. And it's often associated with symptoms like photophobia or meningism, subarachnoid hematomas can show up in a lot of different ways. But the one that frequently pops up in quizzes is a sort of a hyperdense star shape. As you can see here, all the points of the star, an intracerebral hemorrhage or intra parenchymal cerebral hemorrhage that's known by both is an accumulation of blood within the brain parenchyma and arises from the rupture of a small blood vessel. And this can take really any shape or any location within the brain tissue. And on CT you'll sort of see a hyperdense shape, a collection of blood often with surrounding hypodense uh edema to better understand the sort of anatomical location of these hemorrhages. We're gonna sort of go through the layers of the head starting from the scalp as if, where the scalp would drill making that first bur hole. The scalp is composed of five layers from superficial to deep with the first three layers being very tightly bound together and move as a sort of collective structure. These, the first three are the skin which is here, followed by the deep or uh the dense connective tissue which is here. And this dense connective tissue is highly vascularized and innervated. The blood vessels within this layer are actually really adherent to the connective tissue and that stops them from being able to constrict properly. So you can imagine if you can constrict and you lacerate the scalp and you lacerate that area. Um The scalp can be a site of really profuse bleeding following that dense connective tissue, we reach this bit, which is the epicranial a neurosis. And this is a sort of a tendon like structure and it basically connects the occipitalis, which is the muscle at the back of your head to the frontalis muscle, which is the muscle at the front of your head. And these three are very tightly bound together following that. Um There's a layer of loose connective tissue which is this bit here. Um And finally, the periosteum, which is the outer layer of the skull, which is here. And the pneumonic scalp might be helpful in remembering this. Although it's not a perfect pneumonic after hitting the periostomy uh periosteum, we can now move deeper to meet the skull. The skull is a bony structure that supports the face and forms a protective cavity for the brain. The bones of the skull can be considered as two groups, those of the cranium and those of the face. Since we're learning about intracranial hemorrhage, we're gonna skip the bones of the face for this lesson and just talk about the cranium. The cranium consists of a roof and a base. The cranial roof also known as the calvarium consists of the frontal bone, which is this blue one here, the sipal which is the one at the back in orange and the two parietal bones, which is the green, the cranial base however, is composed of the frontal sphenoid which is in yellow, the ethmoid which is in purple here, the septa orange parietal green and temporal, which is that red section that's shaded in there. The bones of the cranial base articulate with the first cervical vertebra also known as Atlas er the facial bones and also the mandible. Er ok, the jaw and the skull, as you can see is comprised of lots of bones. Um but they're not just separate or are loose, they're joined by these fibrous and movable joints called sutures. And as adults, we have three of these, we've got the corona suture which fuses the frontal bone with the two parietal bones. So it's just here. Then we've got the sagittal suture which fuses both parietal bones. This one and this one together. So that's the sagittal suture. And then we've got the lambdoid suture which fuses the septal bone, the one here with the two parietal bones here. Um And in babies when these haven't fused together yet, that's how we get the frontal and occipital fontanelles, which is that soft patch on a baby's head deep to the skull bones we've got the meninges, uh and the meninges are the dura matter here, the arachnoid matter and the pia mater and these cover the brain, but they also do continue inferiorly in the spinal canal to cover the spinal cord. And also the nerve roots, there are real and sort of potential spaces between meninges by potential. I don't mean um, that they're not, they don't exist but uh by potential, they're sort of the ones that don't occur naturally. And if they are occurring, then there's probably a problem. So as you can see, um the dura which is this bit um is heavily uh is very, very closely connected to the cranium here. Uh And in between them is the a potential space called the extra duo space where an extra duo hematoma can form usually from say a middle meningeal artery injury between the dura and the Arachnoid matters. The dura is here and Arachnoid matter is here. Um We have the sub duro space which is a real space and that's where acute and chronic subduer usually from tearing up the bridging veins, which are responsible for draining the venous blood from the cerebral cortex into the Duro sciences. And then between the Arachnoid here and the pia mater here, um we essentially have the real subarachnoid space uh which is filled with cerebrospinal fluid. Uh and also is a space where subarachnoid hemorrhages can occur after assay of the rupture of an arterial aneurysm or an arterial venous malformation. I am not going to cover blood supply uh in, in this lesson because it's a massive, massive topic on its own. And when you're watching a craniotomy, you're probably not going to be able to see much of the blood supply. You'll just see that mass of hematoma, but it might be something useful to revise if you are going to see a craniotomy. Um, if you're going to be looking at, say a CT and someone asks you, oh, where, where is the likelihood of this bleed being? But generally, you can remember that if it's extra dural, it's probably from the middle meningeal artery. If it's subdural, it's probably from the bridging veins. And if it's um subarachnoid, um it's, it could be sort of anywhere or which isn't sort of very helpful. Um Same with intracerebral hemorrhages, the intra parenchyma, it can be sort of anywhere. I will mention a wee bit about the brain. After all, it is the crowning jewel of the nervous system. And there are a lot of various sections. But the big ones to remember are that frontal lobe, which is important for movement and problem solving that temporal lobe, which is important for hearing and language and memory. The parietal lobe, which is important for language and sensations and perception and the occipital lobe, which is important for vision and perception. As you can imagine, the skull is essentially a bony box having the brain, it doesn't have much give. So there's too much pressure on the inside because of too much cerebrospinal fluid or too much blood or even a mass like a tumor. Instead of being able to expand and push out, it just puts extra pressure on the structures within. And so this impact, the impact of this will be different depending on the location uh of uh the location of where the pressure is being on. Uh And that will dictate what sort of symptoms you get and what kind of presentation you get in terms of your patients. Now that you have a little bit of an idea of what we use a craniotomy for and the pathophysiology and anatomy behind intracranial hemorrhages and the layers of the cranium. I'm gonna pass you on to Claire Sue, who's gonna be taking you through the more exciting part, which is the interactive case PSU whenever you're ready. Hello? OK. So let me just get this on to full screen. Ok. Um So I'm clear Sue and I'll be taking you through our first patient of the day. Um So here we have a Miss Sarah Brill, a 22 year old female who presented to A&E after sustaining a strike to the head 1.5 hours ago whilst playing rugby and subsequently lost consciousness for one minute, she regained consciousness and initially felt fine but has been experiencing worsening headache and drowsiness. Since then, she's a healthy young person has no past medical history and doesn't take any medication. So, um, just to go through some head, CT S on the left side here, I'll get my pointer out on the left side here. We have a normal CT um, of the head with no abnormalities. So we can see the ventricles, we can see the center line going down here and no gross abnormalities. And on the right side, we have Sarah's CT head So we can obviously tell that something is quite wrong here. Um Very quickly. Does anyone have any guesses as to the diagnosis? Just by looking at the CT if you can type in the chat, I'll just do a for you. So we've got epidural hemorrhage. Mhm Yes. OK, perfect. So this is an extra dural hematoma or uh epidural hemorrhage. Their names are pretty interchangeable. They mean essentially the same thing. Um A hematoma is um clotted blood whereas a hemorrhage is um sort of frank blood. But to be fair, there's quite a big clinical overlap in them anyway. Um OK. So uh when we take a closer look at Sarah's CT head, we can spot some classical signs of E DH. So here we have a hyperdense area of blood which is biconvex or lemon shaped like Jingjing mentioned earlier. This area has very sharply defined edges. So you can see here and here it very sharply stops. Um So this because the dura is very tightly adhered to the suture lines of the skull, so the blood can cross these um sort of margins here. Um So as the bleeding continues, the hematoma has no choice but to expand into the brain parenchyma into the center. Oh whoops into the center here. Um As it has nowhere else to go, we can see um the signs of mass effect here as well where the hematoma is pushing and compressing the rest of the brain here. So we have a midline shift where the natural center line of the brain is pushed to the side. So you can kind of see that contour going over whereas it should normally kind of go through the center here. Um And we also have an effacement of the ventricles um to the point where this ventricle on this side can actually be seen on the CT and this ventricle is significantly smaller than it should be. So it should be maybe about this big and instead it's this big and this is all due to increased um intracranial pressure. So often an extradural hematoma will be accompanied by a skull fracture. But in many cases, the bone is actually not displaced, which is why it's quite difficult to see any fracture lines if any at all over on this side. And you can kind of see a little bit of blood has started escaping out which shows that there actually is a fracture here. Ok. Um So moving on to the clinical presentation of extradural hematoma. I'm afraid this is a very text heavy slide. So please bear with me. Um I'm very sorry, but um main symptoms on the whole are what you would expect from a head injury. So, headache, nausea, vomiting, confusion, and progressive loss of consciousness. Um The classic history of an extra hematoma is a loss of consciousness immediately after the injury, which is most often due to blunt force trauma. For example, Sarah had a rugby ball hit the side of her head, which is obviously not great um followed by a period of lucidity. The patient will wake up and feel fine and then a progressive reduction in the Glasgow coma score. Um So this is the stereotypical history that you'd often find in MC Qs exams. Examiners love to ask this with this very classic history. Um But in real life, only about 20% of cases will actually present with this sort of um uh disease journey. So, you know, maybe take it with a grain of salt, but it comes up a lot in questions. Um Clinical examination findings will vary depending on the location of the hematoma. However, you will most likely find a combination of cranial nerve deficit and motor or sensory deficit of the upper and or lower limbs. There will also be signs of upper motor neurone damage such as Bin's sign, which is the upgoing um plantar reflex of the foot, um hyper reflex, um hyperreflexia, which can be anywhere in the body spastic, which again can be anywhere in the body and also something called the Cushing's reflex. So, um this can also be seen in patients with extradural hematoma and it is the body's physiological response to a raised intracranial pressure. So, this leads to a triad of symptoms of hypertension, bradycardia and irregular respiration. And often this is sort of ringing alarm bells in your head. But this is a very serious case that we've got here. So, um back to our patient, Sarah, um after reading up on her case, you head to the neurosurgery theater and scrub in to join the surgical team. Um But before the first incision is made, the team goes through a surgical checklist. So the consultant surgeon turns to you and asks what is not asked as part of the surgical checklist? Is it a critical or non and non routine steps or is it b risk of infection POSTOP? Can we get the pull up, please? Ding ding, yep, the po up. Thank you. Ok. We'll give you just a little bit of time. We want to get through this quite quick, quickly. Um What is not asked as part of the surgical checklist? Do we have some answers flooding in now? So, uh 75% 0 no, 53% are going with risk of infection POSTOP. Ok. And uh do we have, is everyone answered? There's about 13 answers. 0, 15 answers. We're still, we're still going with b risk of infection. Ok. I guess we'll go with that then. Right. So, unfortunately, this is wrong. Um, although this is very important, you should always remain vigilant to prevent contamination and maintain a sterile field as kind of your basis for everything. This should kind of be a given. Um, unfortunately, this is not asked as part of the surgical checklist. Um So we'll kind of go through what is asked. Um The World Health Organization developed a standard checklist to try and decrease surgical related errors and adverse events. The checklist also helps to increase teamwork and communication and surgery, which is good as you can see here. It covers various aspects of the procedure including confirming the patient's identity, um anesthesia, the type of procedure um introducing all members of the c the team, including you guys, the medical students in this situation and anticipating critical and nonroutine events. This is a very basic bare bones checklist. Um different regions and different hospitals will all have much more um sort of detailed checklists and I'm guessing quite a lot of them will have a risk of infection POSTOP anyway, but when it comes to the w surgical safety checklist, it does not contain um the risk of infection postop, I'm afraid. So, um here are the members of the surgical team that you might see popping up throughout today's session. So we have the consultant on this side who will congratulate you on correct answers that you give the not so nice specialty trainee who will scold you for getting the questions wrong and the anesthetist, the theater nurse and the scrub nurse who are all lovely. So uh just a content warning for everyone. We are going to be showing images of real life surgical cases with blood, open body cavities. Like if you feel woozy or uncomfortable, feel free to take a break from the screen or leave the page entirely and come back um and grab some water and snack. It's OK. We all feel this at times. Um We'll try our best to give you some notice regarding these graphic images throughout. So keep this in mind um and keeping that in mind the next slide will have some graphic surgical content. So be aware of that now. OK. So um here we can see the surgeon has made a skin flap um of the scalp by making an incision around here marked by these sort of surgical green colored clips um to reveal the skull, which is here warm saline. Here is used to clear any blood um that may obstruct the surgeon's view. And here we can see the surgeon using a bone drill to be able to access the extra dural space line just underneath. Um And in this case, just as a note, we don't need to open the dura as the hematoma lies above this, we don't need to be going around messing with any more of the meninges. So, um here we see that the bone flame removed right here and we can see the hematoma here, which is quite large. So all of this round here is clotted blood. Um The bone flap will be taken to a sterile side table where it will be reconstructed if needed. So, if there are multiple fractures of broken bone um and kept to be placed back on after evacuation of the hematoma. So um next question, whilst the surgeon is removing the bone flap to access the extradural space for hematoma evacuation, she strikes up a conversation with you. Although we are performing a craniotomy for this patient, not all extradural hematomas need to be managed surgically. What one contributing factor would suggest a requirement for surgical evacuation regardless of other findings. Would it be a three millimeter midline shift? A GCS of 11 or a hematoma volume of 35 centimeters cubed? Here we get the next call, please. Jingjing. Thank you. Yep. Everything's going up. Perfect. I'll give you just a few seconds um To answer this. How are the answers looking? Thinking. So we've got 14 responses so far and uh we're going with three millimeter midline shift. Ok. So we'll go with that. Uh Well, the specialty registrar, look at you questioningly, hematoma volume is the most important factor in assessing the need for surgery. Although midline shift is alarming a small change in absence of other factors is not an indicator for surgery by itself. So if we go back and we collect, we select the correct um answer here which is a hematoma volume of 35 centimeters cubed. Um It is a very important fracture to consider when assessing the need for surgical intervention. So um surgeons assess the need for surgical intervention in patients with extradermal hematoma using the brain trauma foundation guidelines. Again, this is a very wordy slide. I'm very sorry. Um The main indicator for surgical management is an epi um epidural hematoma volume of greater than 30 centimeters cubed. So this is regardless of the patient's gla glaucoma scale, any other um sort of clinical signs you can find as well. Um Medical management can be given to patients with an epidural hematoma of less than 30 centimeters cubed with a less than 15 millimeter thickness and a less than five millimeter midline shift. Um It can also be managed medically if the um epidural hematoma is less than 30 centimeters cubed with a GCS greater than eight and without any focal deficit. So, um uh things like weakness in limbs, um patients with an acute um E DH and GCS score less than nine with aoria or a difference in pupil size should undergo surgical evacuation as soon as possible. Um The guidelines um do not outline one specific surgical procedure that should be used, but craniotomy often provides a more complete hematoma evacuation. The alternative is to just use bore holes which are small holes made in the skull to access the extradural space and brain parenchyma. Um And then often the hematoma is just kind of suctioned out. Um But we don't do this all the time. Craniotomy is usually better. Um Just a warning. The next slide shows another graphic surgical image. So click off if you feel a little bit woozy. OK. Um So moving on to the next question, you see the surgeon using forceps here to control the source of bleeding, using ligation. Um She turns to you and asks, what is the most commonly ruptured blood vessel leading to an extradural hematoma? I the pull that dinging. Yup. Perfect. Thank you. OK. So what are people saying ding ding? So we've got 14 responses so far and I'm glad that my um mentions of the middle meningeal artery have been through and 80% have voted for that. 00, perfect. OK. Um So this was correct. Uh The consultant smiles and nods her head. So, rupture of the middle meningeal artery accounts for 75% of all extradural hematomas. Um I there are obviously the other wrong answers. So I'll just go through through them very, very quickly. Um Arterial bleeds are much more common than venous bleeds. Nevertheless, it can happen sometimes. Um So the superior sagittal sinus can sometimes cause an ED H but this is less likely. Um the middle cerebral artery supplies the lateral cerebral surface and lies underneath the meninges. So it would be unlikely to cause an extradural hematoma. It would however be more common in intracerebral hemorrhage, um which is also known as a hemorrhagic stroke. Um And the last one, which is the last wrong option is the superficial temporal artery which supplies part of the face and the scalp. Um It would be unlikely to cause an extradural hematoma as it runs superficial to the skull. Um But maybe could cause something called a subgaleal um hemorrhage, which is essentially just a bleed just under the scalp, but we don't really need to know that. Um So the middle meningeal artery shown down here in this green box is the most commonly ruptured blood vessel causing external hematoma. It arises from the maxillary artery which is a branch of the external carotid artery down here. It lies just underneath the skull and splits into multiple branches, um which I won't go into detail here as they're less important in this case. But what is important is looking at this bony landmark here known as the uh the terion with a um silent pea. Apparently, it is found at the junction of the frontal sphenoid parietal and squamous part of the temporal bone forming a sort of h shape which you can sort of see here. Um It is quite thin um and is known as the weakest part of the skull. So it means that it's very easy to fracture when experiencing a blunt force trauma and as the middle meningeal artery, you can see here kind of lies right under it. Um It can rupture very easily leading to an extradural hematoma. Um Just a warning. Again, the next slide shows another graphical surgical image. OK. Um So here we see the surgeon tacking up the jura to the skull by drawing by drilling very small holes into the bone here and suturing the Jura to it. I appreciate that this is quite difficult to see. Um the image quality isn't very good. I'm afraid you can kind of see little sutures going here. Um This step in the craniotomy is highly contested in the neurosurgery community on whether to use the technique or not because sometimes it can lead to adverse outcomes um POSTOP. But the theory is that the dura is normally very tightly adhered to the skull. So you should um in theory reattach it after removing the hematoma. Um So it's not too important to remember this step. Some surgeons do it. Some surgeons don't. Um There's not really a right or wrong answer here. Um And here we see, the surgeon has placed the bone flat back over and is now fixing it back onto the skull using a variety of plates and screws here. So you can see some small plates here and one sort of bigger one here, which in this case was used to sort of rebuild smaller fragments of the bone so you can see a little fracture line across here, some bits of fracture along here. Ok. Um Another question, um, the surgeon inserts something to the skin that is now lying on top of the skull, so you can kind of see it here and continue round all the way over here. And she asks you, can you name the piece of equipment that I have just placed here? Is it a Jackson Pratt drain or a foley catheter? Pull up? Perfect. Thank you. Do we have some answers coming in? Now, we do. Indeed. We've got 16 responses and 75% are going with Jackson Pratt drain. Ah, ok. Good. Very good. So, um, great job for identifying correctly. The Jackson Pratt drain will help to drain fluid away from the surgical wound in the subgaleal space. Um Just for fun. Um If we did decide to go with the name the Foley catheter, um, the specialty registrar would be very annoyed at you. Um, saying, are you suggesting that we inserted a urinary catheter into the patient's head? Um So very glad that we got the right answer for that one. So the Jackson prep drain is a type of surgical drain that is used to drain bodily fluids that might collect under or near a surgical incision. It also aids in wound healing and can help to prevent infection and also reduce drainage onto surgical dressings. Um It is a closed suction device. So, fluid is collected within a closed system without an outside suction machine and negative pressure draws fluid out of the surgical site. Um from the fenestrated end here around into the bulb here. Um The end of the drain here is fenestrated or has little holes in it to prevent the tissue from being sucked into the tube. Um The Jackson Pratt drain is not only used in neurosurgery, it's actually very commonly used in all types of surgery, um including in general surgery as well. Um Just another quick warning, the next slide will show another graphical surgery, um image. Um Lastly, the surgeon closes up replacing the skin flap back over the skull and suturing it into place. Um So you can see the sutures here and the skin flap here, it's been folded back over. Um And this completes the surgery. So um this, this slide is another yet another very text heavy slide, I'm afraid. Um Hopefully, I'm not losing you all just yet. Um Please keep your focus for just a little bit longer. Um So, postoperative complications, um We have quite a lengthy list here. Um So we have headache, extraaxial hematoma, reoccurring again, um seizures due to mass effect, um electrolyte abnormalities which can sometimes happen, pneumocephalus um infection. Most common being meningitis, extra abscesses, skin and soft tissue infections at the wound site. Um intracranial hemorrhage, um ventilator associated pneumonia for patients that end up going to ICU and requiring ventilation after their surgery. Um cerebral edema, cerebral ische um vasospasm CSF leaks hydrocephalus. And unfortunately, um some patients will not survive this um uh procedure. Um I'll just talk a little bit about prognosis. Um It's highly variable and in the literature, it can range from anywhere from 1.2% to 33% mortality rate. Um factors for poor prognosis include increasing age, a low G CS at presentation. So, in general, about a GCS, less than seven is quite bad. Um No history of a lucid interval, pupil abnormalities. Um So, ns equia like we talked about before, um decerebrate rigidity, um any sort of preexisting brain injury or any evidence of brain herniation and or uh raised intracranial pressure. Um The most important thing that I want you to take from this case is that early assessment and intervention is key to reducing mortality and improving prognosis in not just patients with extradural hematoma, but for all patients who experience a traumatic brain injury, these are very serious injuries um and they can be very easily life threatening. Um and if a patient does survive, they can often end up with permanent disability. So the faster we can look at it, identify it and be able to sort of fix it the better it is for patients outcomes in the long run. Um ok, so to summarize, we covered craniotomy. Um and one indication of this which is extradural hematoma, um make sure to know your anatomy. So, in particular for this case, we covered the skull layers of the cranium and the lobes of the brain. Um Miss Brill is successfully transferred to the ICU for recovery. You check the theater list and see that a transphenoidal procedure is happening in 20 minutes. What do you do? Um And I am afraid both the options are the same. Um We shall hit the books and learn about transphenoidal surgery and I will switch you over to Anton. Yep. Thank you, Clare, sir. So, hi everyone. My name's Anton. I'm another one of the fifth year medical students. It's delivering this teaching. Um I will be discussing transphenoidal surgery and basically the key anatomical structures that you should be aware of. So to kind of just start off, we'll have a wee look at 11 objectives. So we'll be covering pituitary tumors, pathophysiology and symptoms as transphenoidal sinus surgery is used to resect these and it's important to know about the effects and the causes of these tumors. So you have an idea of why the surgery is happening. Oh, sorry, my bad. Um So we will then move on a little bit and we'll learn more about the anatomy involved in the surgery. But the main areas of focus being the nasal cavity, the facial sinuses, the cavernous sinus and also the CT which will cover layer. And then again, we'll go through the patient case, we'll have surgery clips and basically you'll get some questions for just to get test knowledge that we cover so far. So just to start off with its pathophysiology of pituitary tumors. So overall, about 17% of brain tumors are diagnosed are found to be pituitary tumors. So that means it's roughly one in five tumors are uh found are found to be of pituitary origin. Most of these are benign and due to this, they are called pituitary adenomas. There are other ones that are called pituitary carcinomas which are malignant, but these are very rare. Uh and in the pituitary adenomas, prolactinoma and nonfunctional pituitary adenomas are the most common types you'll find um in terms of clinical features. Um they can basically, most people present asymptomatically and it's usually just found through kind of different incidental investigations. So whether that might be a CT head or, well, they might get kind of bloods that might then show as we've got here. It next clinical feature, more hormonal dysregulation. So with a pituitary gland is a gland which produces hormones. Uh that's being uh hormones such as prolactin, which is increased in prolactinoma also produces LH and FSH that's involved in kind of sexual reproductive uh development. They also have other kind of hormones such as growth hormone which is released amongst a, a few other ones. Um Other symptoms that they may develop as visual disturbances. Uh This is mainly just due to the underlying anatomy of where pituitary gland sets and are associated nearby structures such as optic nerve. So if pituitary gland gets a bit bigger, it can cause compression, but we'll cover this later and also headaches just because of as had mentioned earlier, the skull as a bony box. So any increase in pressure is going to maybe cause things such as headaches. So again, I'm just going to cover about this bony box. So effectively, the when looking at the brain and skull, the skull effectively acts as a pony box, which in case is the brain to protect it. Although it does play this vital role as we don't want trauma reaching the brain directly due to the stiff and inflexible nature of the skull. Any increase in volume is going to ultimately cause possible neuro effects. Um In this case for a pituitary tumor, um basically, the pressure can increase uh causing headaches. Uh And with more focus on the anatomy, we know we know that the pituitary gland is located in a depression in the skull known as the Tusa, which we mentioned in the uh objectives. And basically the enlargement of this pituitary pituitary gland eventually will exceed the capacity of this uh depression. And basically, it will push up right out of CUSA and the optic nerve just lies on top of it, try to make its own business, but then two or three pushes on it and compresses the optic nerve which then can lead to visual disturbances, which is one of the kind of common clinical features. So as we can see here, this depression as the t in the bone and pituitary usually sets very nicely in here and it can push up especially this optic chiasm which overruns the top of it or two next slides. So in terms of indications for management, uh this can be if it's under like tumor. If it's cancerous, we don't want it there, but we'll go in and try and remove it. Uh hormone producing tumors. So obviously, if you have hormone producing tumor, it can cause a lot of negative side effects. For example, with the prolactinoma, which is one of the most common. Uh the release of prolactin ultimately reduces luteinizing hormone and follicle stimulating hormone levels um which can lead to a loss of libido in people, uh irregular periods and erectile dysfunction, which is might be some of the symptoms along with kind of other things such as growth hormone that can maybe cause agro megaly. And obviously, the other, let us say the effects come with that. Uh The other one is non hormone producing tumors. As the name suggests, they don't produce any hormones or really just a space occupying lesion. However, these can grow to quite a substantial size. So if they're causing too much pressure in the brain, want to remove it at least try and give them back some quality of life. Uh Again, visual disturbances, headache and an increase in inter cranial pressure are also indications for surgery. But one thing to keep in mind is despite this being a surgical talk, there is some, there is medical management that can be done for pituitary tumors. Does anyone have any idea what the most common tumor that's managed medically is, is I should say pituitary tumor that has managed medically correct. It's a prolactinoma. So prolactinoma can be managed through dopamine agonists and this can actually help to reduce the size and doesn't actually mean that we have to go in and surgically remove the tumor, which is very handy because no one wants to go through surgery. So I'll move on to the next slide. So now we can move on more to the relevant anatomy. Um So to start off with, we kind of cover up the nasal cavity, the structures that are inside and obviously kind of what this is. Why are we talking about nasal anatomy when it comes to a neurosurgical procedure? So just to start off with in the nasal cavity, there is a few main structures that I want you to be aware of. This is the turbinates or concha. These names can be used interchangeably. People say different ones. I will just take the turbinates just for, just to kind of keep it the same er paranasal sinuses and also the crib plate. So just to kind of start off, I will cover about the turbinates. So, and the turbinates, these are projections are usually found in the medial aspect of each side of the nasal cavity. So you have a left and right. Um And as we can see here, they are kind of projections that come out the middle and then go down the way and there is three on each side. So first to start off with, we have the inferior turbinate, we then have the middle turbinate and then we have the superior turbinate. So the roles of these play in the nose is to basically help increase surface area uh to help warm and humidify the air while also regulating nasal flow. Because basically, when we breathe, we do need the air to be warm and humid. Because if it's cold, it'll dry out the nasal cavity in the throat, which can then lead to kind of issues that we don't want. Um I will then move on off the s that's all we really need to know about them. Uh So now we'll move on to paranasal sinuses and total. There is four within the skull. In this image, we can only see two. But in the next slide, we get to see all four and I can point out the other two. So to begin with, we have the frontal sinus which sits here right at the front of the skull. They also have the ethmoid and maxillary, which is not present in this image. And then we ultimately have the sphenoid, the sphenoid sinus, which is going to be the main area of where the surgery occurs. Uh And basically the role is for these is to produce mucus. So when we all have colds flus and we get that kind of stuffy mucus coming out of her nose. It's actually just because of frontal or sinuses are acting uh responding and producing mucus. A mucus effectively in the nasal cavity acts as a filter, which is why it's useful. It basically helps to collect dust, allergens, viruses, microorganisms that we don't want our airway. Um Furthermore, it also acts to humidify the air some to about the top and it to uh also due due to the nature of sinuses, there are hollow structures within the skull which ultimately lighten the skull. So I'm very thankful for that because in my case, my head's quite big. If I had more bone in there, it would be 10 times heavier and I wouldn't be able to look at the screen. And also because of its hollowness, it also helps increase vocal resonance within the skull when you speak. So that's where you can maybe kind of hear it going through your entire head rather than just being quite a dull bony structure and moving on, we will then talk about the plate. It's not necessarily a structure that is involved in the surgery, but I feel like it's something to always keep in mind when you're dealing with the nasal cavity. So it's fine, the superior aspect right about this area, this being the f my bone. And basically, it's a frate bony structure just meaning it's got a few holes in it. And basically that allows factory e to get projections through to reach the nasal cavity, which is involved in smell detection. And then these signal back to the nerve and then go to kind of brain regions that then manage kind of smell and also the memory that comes along with it. So we'll move on now. So again, as I mentioned about the sinuses, we had the frontal sinus. Um the maxillary sinus and ethmoid sinuses are hard to see in the view that I showed previously. But if you can appreciate here that the maxillary sinus is found roughly just the kind of your cheek bones at the front and to the side of the nose. You know, the ethmoid sinus has er sinus holes around about the inside of your eyes and also towards kind of the sides of your eyes. Uh Furthermore, I just feel it's also handy to know especially for this surgery about sinus openings. Um So as I say, the sinuses produce mucus that come out into the nasal cavity, but to do this, they need holes. Um So in this case, we have the semi semilunar hiatus which is provides opening for the frontal maxillary and anterior ethmoid sinus. And this comes that usually projects underneath the middle tint and produces mucus cell. You then have the FMO bulla which does the middle FMO sinus. And again, that is a similar position right about underneath the middle of it. And then we have the sphenoid sinus which has an opening of its own and it's fine, more towards the superior and inferior as uh sorry, not superior and posterior aspect of the nose of the whole coming around about at the superior level of the superior, but then also have just extra wee ducts and we have the eustachian tube peel which is found more towards the back of the throat, multi towards the oral pharynx. So moving on, um I then have want to explain the cavernous sinus. I feel like this is a very important structure to discuss in this uh topic. Uh partly just because of its location near to the sell at. So basically, it's a sinus which is found on both sides of the pituitary. So as you can see here, it covers all this way and it's also found just just above the sphenoid sinus. So it will be kind of close to where the operations occurring, which is why I want to kind of talk about it. And it includes multiple important neurovascular structures. So here as we can see, it contains internal carotids from both sides. So it passes through the cavernous sinus and projects up to the brain. Um but then we also have a few kind of motor nerves and sensory nerves. So we have the ocular motor nerve that controls the muscles of the eye, the trochlear nerve, which deals with the eye ophthalmic nerve, which is a branch of the trigeminal, the maxillary nerve, which is a branch of the trigeminal. And then we have the a just nerve which is also another eye nerve. And in addition, due to it being a this uh sinus is also involved in venous drainage, uh anastomosis with the facial vein to help provide drainage for multiple facial structures. And basically due to this, there is an increased risk of infection, uh being able to easily travel to other structures from here. And it's also possibly involved if they get a clot in here. It's also known as a caval sinus thrombosis, which is something that you may have to be wary about. And again, just about the t in case it's pituitary and it's fine superior to the sphenoid sinus. And due to its position allows minimally invasive access rather than having to maybe go through the skull uh at the top, try to kind of go through other structures to get to the pituitary through this. We can kind of go through the nose and the sphenoid sinus and then kind of drill up and through and get to the pituitary that way and then try and do the operation. So we're kind of move on to a patient uh case the now. So we have Miss Pa who's a 27 year old female. Uh she presents with an onset of left visual field disturbance, headache and fatigue. She has no past medical history in terms of her drug. She's only on the combined oral contraceptive pill. And for her social history, she lives with her boyfriend, she's a nonsmoker, she's independent and she's also a financial advisor. So you get this referral from the GP uh and you decide to kind of do a few tests. Does anyone know what kind of test we would do or investigation more specific imaging investigation that we've do to maybe try and see a pituitary tumor? I will take it that everyone is shy and I will move on. Oh, yep, it's MRI. So you send the patient for an MRI and basically what we see here is this kind of lesion here. Most people might be like, what is it? But this is basically she has came in and her pituitary seems to be enlarged. And when we kind of look at this uh section, we can see that the tumor is here. And if you could appreciate kind of where I'm outlining just now, this looks to be the optic nerve. So as we can see the pituitary is pushed up causing compression of the nerve, which has then ultimately led to her visual disturbance. So, moving on after an MDT discussion, the surgical team decides on a transphenoidal approach to remove the tumor. And although it is a neurosurgical er lecture that we're doing. Uh This surgery usually involves ent and neurosurgeons working collaboratively with ent beginning the surgery, placing the endoscope into the nose and basically to navigate to the pituitary. Then once you get to the pituitary, the surgery will take over, create the opening which exposes the pituitary and then remove the tumor in small pieces before closing up and taking away the endoscope. Uh Bianca. Yes, the slides will be recorded and feedback will be placed in the chat. So, uh we move on to complications now. So the main complications uh of this type of surgery is CSF leaks. This is partly because again, it's a brain surgery. You're kind of moving it, you're going to be cutting open the JRA, uh which means that you've got that space left for CSF to leak and it can come out and if it's not fully sealed properly, you can then kind of get the CSF leak tir again, meningitis as always kind of a an operation especially around about the brain. Uh, if strict infection controls are not met, uh, infection can occur and it can obviously infect meninges causing meningitis. Uh rhinosinusitis, it just kind of occurs mainly just through the nature of the operation. We're going through the nasal cavity and through the sinuses, these areas are gonna kind of get a little bit irritated just throughout the surgery. So you're gonna kind of get that stuffy nose m mucusy kind of type P that you get with rhinosinusitis. And for the last two, we are dealing with the pituitary, there is going to be some trauma to the pituitary when we're trying to take it out. And obviously, as we know, the pituitary is involved with ADH secretion, which obviously helps with water retention. And again, if you damage the pituitary, you are likely to maybe not really a DH, which can lead to diabetes and sepsis. And also because the pituitary is a bit battle improved, it might not want to work for a while. So you may get hypopituitarism, which then means obviously you'll have a decreased lack of hormones being no for a while. But moving on, we'll move on to the content one now. So as always before it is going to contain kind of some images that might not be pleasant to view. So it's OK to feel woozy. And if you don't wanna have a look at it, that's completely fine. You can come back for the questions and maybe go and have a wee drink or a snack at the moment if you want. So, moving on. So we move on uh again because this is more of a endoscopy procedure, we're not gonna get a full, full wide view. So apologies for kind of the circular view of the operation, but the team begins the procedure with the ent consultant pushing the uh endoscope into the nasal cavity. So they've went up and through the nose the consultant then stops advancing the endoscope. And after she does this, she asked you what landmark of the nose have I stopped that? Which I've marked out with arrows here and here. Just give a couple of more minutes for responses to come for and we'll call it there. So, uh every uh basically, we have 66% of people saying that it's the sphenoidal, sphenoethmoidal recess. So click that, which is correct. So tilting smiles, nods or head. Yes, that's right. Sphenoethmoidal recess is located at the posterior aspect of the nasal septum. Uh We can tell we are here as we can see both the sphenoid sinuses opening bilaterally and the ulna being medial to both. So again, I should also preface this when we're doing the surgery, we want good visualization. So what they will do is they will remove some of the middle part of the nasal cavity which separates both to kind of get a view. But again, also one thing that we could tell as we couldn't really see any metal uh turbinate as we know the semi hiatus is located underneath that. Therefore, it shouldn't be that because we haven't had to move out the way and your station tube is just located a little bit lower down inferiorly and wouldn't be kind of the area that we wanted to go for the operation. So that's why it was the sphen ethmoidal recess. So we move on. Uh basically before the NT consultant decides to hand over the surgery to the n uh neurosurgical team. She ask you one more question. Although the structure is not usually involved in the surgery. What nerve has projections into the nose? Is it either the optic nerve, the facial nerve or the olfactory nerve? All right. I think we've got a pretty resounding winner here at 100% for the olfactory nerve, which is correct. So, the again, consultant smell nods her head. She's very impressed. Uh Yes, that's right. Olfactory nerve has projections which descend through the Creon plate located at superior aspect of nasal cavity that helps in detecting smells and sending sensory information to the brain again with uh for the incorrect answers, optic nerve as we know passes over the pituitary. Uh again, it's not really going to project into the nasal cavity. Um The facial nerve is not directly involved. I'll send projections to inside the nasal cavity. Some branches of the facial nerve do provide sensory information, but they don't project directly and they mainly just innervate kind of the local mucosa rather than projecting into the nasal cavity, which is why it's incorrect. So, moving on, uh for this. So basically neurosurgery I've now advanced, took over the surgery. Uh And here we have the pituitary gland in the middle. So what they have done is the sella that I've marked here as you can see the bony structures here, they have basically been driven away at that to kind of expose pituitary gland with the dura on uh covering it. Uh And then after the finished drilling, they decide to do something. So the neurosurgical consultant takes all the surgery and advances in. She drills into the and exposes the Jura after she does this, she uses a Doppler ultrasound, what I've marked here and white. And afterwards she asks you, what important vascular structure am I trying to locate here with the Doppler? Is it either the external carotid, the spal palatine artery or the internal carotid artery? Just have a couple of more seconds. All right, we'll call it there. We have 84% are voting for the internal carotid artery which again, the consultant smells her head and nods, uh, smells. She smiles and nods her head. Yes, that's correct. The internal carotid artery branches from the common carotid and provides blood flow to many structures including the brain and pituitary.