Hello everyone, my name is Olabisi Sanusi, I'm one of the neurosurgeons in Oregon Health and Science University in Portland, Oregon. I have no disclosures. Today we're going to discuss different types of intracranial hemorrhages and review the indications for surgery. We will also be reviewing different types of vascular malformations, we'll discuss cerebral spinal fluid diversion, the different types of diversion and the indications for it. We'll also review bedside neurosurgical procedures such as lumbar drain placements, and then lastly we'll review endonasal surgery and pituitary apoplexy. We'll start by discussing craniotomy for extra axial hematoma. Over to the right is a picture of an 87-year-old man who was found down and presented with bilateral left gridded and right subdural hematomas. Subdural hematomas are a common occurrence with a reported incidence of 15 to 20 per 100,000 patient years. The density of the hematoma could vary and the clinical presentation of the patient also varies. During the breakdown and oxidative process of hemoglobin, the hematoma size can increase in size as there's an associated inflammation that occurs with release of vascular angiogenic factors as well. And during that process, patients can become symptomatic. Ideally for small acute subdurals with minimal midline shift in patients who are asymptomatic, ideally try to wait until the subdural chronicifies as this could decrease the size of the need of craniotomy. There's also potentially a role for middle meningeal embolization and use of steroids in chronic subdurals. However, this remains controversial. Epidural hematomas typically result from fractures in the squamous temper of bone with result in injury to the middle meningeal artery. There's a high potential for enlargement of the hematoma with the resulting rapid decline in the patient's exam. We must always have a concern for underlying primary brain injury with potential for combined subdural hematoma in addition to the epidural hematoma. As such, during surgery, one must decide if to open the dura and if to leave the bone off. The fourth edition of the TBI guidelines stated that bifrontal decompressive craniotomy is not recommended to improve outcome at six months in severe TBI patients with diffuse injury, but it has been demonstrated to reduce ICP and ICU stay. That's a level 2A recommendation. It also stated that a large frontal temporoparietal decompressive craniotomy at least 15 centimeters in diameter is recommended over a small one for reduced mortality and improved neurologic outcomes in patients with severe TBI. That is also a level 2A recommendation. It is important to note that the guidelines stated here included the six-month outcome from the DECRT trial. The DECRT trial is a decompressive craniotomy trial that included patients with refractory ICP to medical therapy after 72 hours with diffuse TBI. It compared bifrontal temporoparietal decompressive craniotomy to medical care such as pento-bob coma. In the DECRT trial, the ICP setting used was ICP greater than 20 millimeters of mercury for 15 minutes over one hour period despite tier 1 treatment. In the DECRT trial, secondary analysis of functional outcomes was performed at six months and at 12 months. At six months, functional outcome was worse after decompressive craniotomy. However, at 12 months, the odds ratio of worst functional outcome after decompressive craniotomy, although higher than standard therapy, was no longer significant. The RESQ-ICP trial is a trial that was released in 2016. It has some similarities and differences from the DECRT trial. For one, it permitted unilateral or bilateral decompressive craniotomy for refractory severe TBI. It also used late refractory ICP, which was defined as ICP greater than 25 millimeters of mercury for 1 to 12 hours and refractory to tier 2 treatments within 10 days of admission. Surgery also had to be done no later than 4 to 6 hours after randomization. Overall, what they showed was there's a survival advantage of decompressive craniotomy when it's used as a last resort treatment for IICP. And that survival advantage is seen for both dependent and independent live-in. There still remains this gray area as to when the exact timing, when is the appropriate timing to offer decompressive craniotomy. But overall, these trials underline the importance of having goals of care conversations with the patient's power of attorney or next of kin. The updated guidelines after the 12-month results of the DECRT trial and the rescue ICP trials provided new level 2 recommendations, which included secondary decompressive craniotomy for late refractory ICP elevation is recommended to improve mortality and favorable outcome. Primary decompressive craniotomy for early refractory ICP elevation is not recommended to improve mortality and favorable outcome. This is not to be confused with primary decompressive craniotomy, which is craniotomy that's done once the patient arrives, such as patients with subdural hematomas. You evacuate the subdural hematomas and also leave the bone flap off. Another recommendation was a large frontotemporal parietal decompressive craniotomy measuring at least 15 centimeters in diameter is recommended for reduced mortality and improved neurologic outcomes in patients with severe TBI. And secondary decompressive craniotomy as a treatment for either early or late refractory ICP elevation is suggested to reduce ICP and duration of ICU stay. In terms of intraparenchymal hemorrhages, after confirming a negative vascular imaging, one could consider hematoma evacuation. There's the MRSA trial, which was a trial that looked at passive evacuation of intraparenchymal hemorrhages. And essentially, a catheter is placed stereotactically, and then a thrombolytic agent is injected through the catheter gradually. The investigators of the MRSA trial subsequent to the release of the results of the trial later showed that the amount of the hematoma evacuated affects mortality benefit, with a benefit achieved at greater than 53% volume reduction of the hematoma. There's currently an ongoing trial looking at active evacuation with the use of an endoscope. And then in terms of superficial intracerebral hemorrhages, there's the STITCH trial, which is also a randomized clinical trial that essentially showed that early surgery within 48 hours might have a small clinically relevant survival advantage. And then there's the CLAIR trials, most recently the CLAIR-3, which looks at intraventricular hemorrhage, and essentially looked at instilling TPA via an external ventricular drain slash ventriculostomy. And what they found was ITTPA does not improve functional outcome in these patients. Shifting gears to talk about posterior fossa hemorrhage, this is a 63-year-old woman who came in with nausea, vomiting, and lethargy, and was found to have the cerebellar hemorrhage that you can see on the picture on the right. Posterior fossa craniotomy can be used to treat patients with cerebellar strokes or patients with cerebellar hemorrhages with impending brainstem compression. It is important to perform a wide craniotomy with expansile duroplasty, ensuring that the foramen magnum is appropriately decompressed. Other indications for posterior fossa craniotomy include Chiari malformation decompression, cerebellar resection, and resection of vascular malformations. When there's severe edema and brainstem compression, one has to watch for delayed hydrocephalus. And occasionally, an EBD is needed simultaneously and then weaned over time as the edema subsides. There is a risk of upward herniation if that ventriculostomy catheter is used to drain spinal fluid prior to decompressing the posterior fossa. Let's talk about penetrating injuries. More than 90% of civilian GSWs die, with almost two-thirds of them dying at the scene. There are different types of velocity of objects, low velocity versus high velocity. And one also has to consider primary versus secondary insult to the underlying brain parenchyma. Penetrating injuries can cause different compartments of hemorrhages and traumatic aneurysms and arteriovenous fistulas as well. A 3D CT of the head is useful to evaluate these injuries and then add in some form of vascular imaging, particularly if there's a suspected underlying vascular injury. Penetrating objects can be associated with CSF leak, infection, whether that's early or delayed infection, and also post-traumatic epilepsy. Current guidelines recommend prophylactic antiphylactic drugs for the first week after such an injury. And then the role of surgery includes wound debridement, removal of the retained fragments, and then ensuring a watertight dural closure and use of prophylactic antibiotics in select cases. Shifting gears to talk about ICP monitoring and severe TBI, we'll start with a 15-year-old girl who came in after a motor vehicle accident, combative and bleeding from the mouth. Her CT scans are shown at the bottom there without any intracranial hemorrhages. She also had multiple abdominal injuries requiring an X-slot. ICP monitors are typically placed in the right frontal region using a twist-drill burr hole. Current guidelines recommend using information from ICP monitors to reduce in-hospital and two-week post-injury mortality. That's a level 2B recommendation. There are, however, papers looking at parameters that can be used to guide intracranial hypertension treatment in the absence of ICP monitors, particularly in low-resource settings. There are different types of ICP monitors. There's the external ventricular drain slash ventriculostomy, and then there are intraparenchymal monitoring devices. Ventriculostomies are not only diagnostic, but they can be therapeutic. They are, however, more technically challenging, particularly in patients with small ventricles. But this can be done with navigation to improve its accuracy. With ventricle monitoring devices, less precision is needed. However, these devices can easily be dislodged. And once they're dislodged, an entirely new system is needed. They can also be used to monitor brain temperature and oxygenation. The indications for placement of an ICP monitor includes a GCS less than 9 and a patient with an abnormal CT. That's a level 2 recommendation. In patients with a normal CT, two additional risk factors are needed, including age greater than 40, being hypotensive, or having decerebrated or decorticate posturing. There are two different trials of importance, including the Chestnut trial in 2012 that was performed in South America. It essentially compared ICP to non-ICP slash imaging clinical examination group. And they show that there was no statistically significant difference in the ICU length of stay, six-month mortality between the groups. Their overall conclusion was care based on ICP monitoring was not superior to care based on imaging slash clinical examination. It is important to note that the ICP monitor used here was not ventriculostomies. In 2015, there was another paper that essentially looked at the same thing, but they used propensity score matching. And the ICP monitor used here was ventriculostomies. They found a six-month mortality benefit, especially in those patients with GCS of three to five. There are many different complications that are associated with ICP monitor placement that ranges from tract hemorrhage to infection to dislodging of the catheter slash bolt. Overall, the compliance of ICP monitors remains somewhere in the 50% range. In terms of subarachnoid hemorrhage, that could be aneurysmal or non-aneurysmal. For aneurysmal subarachnoid hemorrhage, depending on the severity, it may lead to obstructive or communicating hydrocephalus with need for CSF diversion. When treating aneurysms, there's different treatment algorithms, including coiling versus clipping versus a combination of stent coiling versus pipeline. For treating aneurysms, there are many different patient and aneurysm characteristics that play a role in the treatment decision. Particularly for ruptured aneurysm, there's a landmark trial called the ISAT trial that essentially show that coiling decreases the risk of death and dependence in ruptured intracranial aneurysms. And that essentially shifted the gear for ruptured intracranial aneurysm towards coiling. However, one must weigh the risk of that and understand the long-term aneurysm recurrence between coiling versus clipping differs. For unruptured aneurysm, the decision depends on multiple different things, whether you clip versus coil. You have to consider the patient's age. You have to consider the neck dome ratio. You have to consider the location of the aneurysm. You have to consider the size of the aneurysm. And the multiplicity of the aneurysm, as well, plays a role. Shifting gears to talk about vascular malformations, starting with cavernomas. Cavernoma is also known as cavernous angiomas. These lesions can be sporadic, familial, or radiation-induced. The MRI over to the right shows a patient who was in his 40s who presented with seizures and was found to have this cavernoma. Classically, on T2 sequence, they have this popcorn appearance. In the familial version of cavernomas, it's thought to be autosomal dominant. And the CCM1 to 3 genes in most of these individuals have multipocal lesions. Patients with cavernomas can present with seizures. They can have symptomatic hemorrhage. They can have focal deficits without evidence of hemorrhage. So these lesions can also be found incidentally. Cavernomas are characterized by dilated vascular space with single-layer endothelium, lack in mature vessel wall angioarchitecture. And in general, cavernomas are angiographically occult, meaning if you were to do an angiogram, you wouldn't see anything of note on the angiogram. 0.08% per patient near risk of hemorrhage in incidentally found cases. However, once they've bled, they do have a propensity to continue to bleed. And the risk increases significantly with a five-year risk of hemorrhage of 42%. Brain stem cavernomas are also thought to overall have an increased risk of hemorrhage. And as such, are more difficult to treat. In general, for cavernomas, the treatment options include symptom control, particularly if it's found incidentally or if there's significance around an edema, symptomatic hemorrhage, essentially letting them cool off, so to speak. Surgical resection is another treatment option. And then radiosurgery is another treatment option for cavernomas as well. Another type of vascular malformations are aterovenous malformations, AVMs, which are abnormal connections between arteries and veins with the presence of anitis. AVMs come with a 2% to 4% yearly risk of hemorrhage, and patients can present with symptomatic hemorrhage or seizures. Over to the right is a 29-year-old male who presented with intraparenchymal hemorrhage and intraventricular hemorrhage and was found to have a right occipital AVM. There are different grading systems for AVM, including the Spetzla-Martin grading system that essentially looks at the size of the AVM if the AVM is an eloquent brain cortex and the venous drainage pattern. There's also the Lawton Young Supplemental grading system that looks at age, ruptured or unruptured, and whether or not the anitis is compact or diffuse. AVMs can be treated in different ways, including embolization for cure for small AVMs, embolization as an adjunct to surgery, or as an adjunct to radiation. It is important to know about the AROBA trial, which is a randomized trial of unruptured brain AVMs, that essentially looks at medical management versus intervention in unruptured brain AVMs. It showed medical therapy alone was superior in the prevention of death or stroke in patients with unruptured AVMs. However, some of the criticism of this trial is in the intervention arm. It included surgery, embolization, and radiation, with a high number of patients undergoing Shifting gears to talk about CSF leak, CSF leak can be idiopathic, traumatic, or iatrogenic, and patients can present with frank CSF rhinorrhea, meningitic, they can present with positional headaches, they can present uptended, or have extra axial hemorrhage. The treatment algorithm varies and essentially includes some form of CSF diversion with or without antibiotics, depending on the presentation. A skull-based MRI and a skull-based CT is needed to identify the skull-based defect and to evaluate the extent of neurocephalus, if any, and evaluate for the presence of an encephalocel. Surgery for repair varies and can be endonasal, meaning through the nose, or transcranial, meaning through the head, depending on the defect, and essentially a team-based approach is required that involves ENT, oculoplastics, and neurosurgery. Shifting gears to talk about bedside procedures, lumbar drains and lumbar puncture, both are essentially positioned in a similar fashion, patient is placed in a fetal position, and the intrathecal space, particularly at L4-5 or L5-S1, is palpated and the region is cleaned. This is typically done free-handed, but can also be done with or without fluoroscopy. There are some complications that can occur with a lumbar drain placement that includes fracture of the catheter, the catheter is very small and can clog, infection is another risk, a nerve root injury, CSF leak with need for blood patch after removal, or spinal hematoma. The main difference between lumbar drain and lumbar puncture is the size of the TUI needle and the fact that a drain is left in place after a lumbar drain versus in a lumbar puncture, it's one and done. Shunts are permanent CSF diversion, there are different types depending on where the proximal catheter is and where the distal catheter goes. The name of the shunt tells you the drainage pathway. There are also different types of valve, there are programmable valves and non-programmable valves. Programmable valves need to be checked after MRI, as the MRI can change the setting of the valve. There are different indications for shunt placement, including obstructive and non-obstructive isocephalus. Sometimes during persistent CSF leak after an anterior skull base surgery, shunts can be placed, however, prior to doing this, the anterior skull base defect is repaired. Shunts can also be tapped as there's a proximal reservoir. Typically we use a small gauge needle, CSF pressure can also be estimated during that process. There are different indications for a shunt tap, which includes CSF analysis if one is concerned for meningitis, but there's a risk of infecting the shunt during that process. Shunt taps can also be done to evaluate the proximal functioning of a shunt or to use it as a temporizing measure to drain excess CSF. For example, when a patient comes in with a distal shunt malfunction, in the situation of a fixed valve setting and a patient comes in needing extra CSF diversion and one has to change the valve to something that would allow for more CSF flow, one can also drain CSF as a temporizing measure. The shunt can also be externalized at the clavicle in instances where there's a compromise of sterility of the peritoneal cavity. Here's an example of a patient with communicating hydrocephalus who got shunt placement. This is the post-op CT over to the left, and then the post-op shunt series. You can see that there's a proximal catheter, there's the valve, and then there's the distal system. This was a ventricular peritoneal shunt. There are different types of implantable CNS stimulation, including DBS, VNS, and responsive neurostimulation. All three can be used for electric stimulation for epilepsy. However, DBS is commonly used for movement disorders, such as Parkinson's. It has also been explored for a number of neurologic and psychiatric disorders, such as OCD. The mechanism of action of DBS is complex, and it's not fully understood. Vagus nerve stimulation can be an option for patients with medically refractory seizures who cannot undergo surgical resection, or those who have failed surgical resection. The vagus nerve is identified in the carotid sheath, a lead is placed around it, and it is connected to a generator. The mechanism is not fully understood. However, it is thought that sensory afferents of the vagus nerve projects to the nucleus of the solitary tracts in the medulla, which then projects broadly throughout the brain. There are trials on less invasive alternatives, including transcutaneous VNS. Responsive neurostimulation, on the other hand, uses direct cortical stimulation, where two-depth electrodes or a subdural electrode is placed and used for focal epilepsy that's unresponsive to medical treatment. RNS mechanism includes detecting seizures, and then it interrupts the seizure activity using direct cortical stimulation. It's most limited to direct application at the seizure focus. However, there are reports of application in the thalamus as well. Here's a picture of what RNS looks like. At the top, you can see skull X-rays after placement of RNS. At the bottom, you can see sagittal and axial-veal MRI showing the depth electrodes in the mesiotemporal lobe. Another procedure one may encounter in a postoperative neurosurgery ICU patient or endonasal approach There are multiple indications for this, including anterior skull-based tumors, such as pituitary adenomas and olfactory group meningiomas, after trauma with anterior skull-based fractures with resulting CSF leak. The procedure can be done typically with an endoscope or a microscope. There are multiple postoperative concerns one should be aware of, including persistent CSF leak, CSF overdrainage, subarachnoid with resulting vasospasm. Over to the right are two pictures of pituitary macroadenomas in patients who presented with vision loss. Patients with pituitary adenomas can present with pituitary apoplexy, which includes sudden onset headache, nausea, vomiting, vision loss, vision decline, lethargy, coma, and death. It can easily be missed because a vast majority of patients have an undiagnosed adenoma. Pituitary apoplexy is due to rapid expansion of a pituitary adenoma from hemorrhage or infarction of the adenoma. There are published inciting factors. However, most of these do occur without an inciting event. Some of the inciting factors listed include major surgery, such as cardiac surgery, after pregnancy delivery, anticoagulation, and overall reduced blood flow to the gland. Treatment for pituitary apoplexy is typically a combination of high-dose steroids and surgery. However, conservative management with hormone replacements and high-dose steroids can be used in select cases. To conclude and to wrap up, we've talked about many different procedures and diagnosis. There are many procedures in a neurosurgeon's armamentarium, and ultimately, multidisciplinary patient-centered approach is key. I hope that you've enjoyed this lecture and found it useful. And with that, I say thank you very much for listening and for your undivided attention.

neurosurgery

intracranial hemorrhages

vascular malformations

cerebral spinal fluid diversion

endonasal surgery

pituitary apoplexy