My name is Jack Giallo, and I will be discussing chronic subdural hematomas and current management as well as developments. I have no disclosures relevant to this slide. The structure of the talk will be to review some epidemiology, followed by a basic and relatively recent pathophysiology. Some evidence-based guidelines or recommendations. Review some surgical decision-making questions, and then summarize the discussion. As all neurosurgeons know, chronic subdural hematomas are common and an increasing condition that neurosurgeons need to address. Currently there's no consensus regarding management strategies, and there's a fair amount of variability between one center and another, and even amongst different neurosurgeons within a given center. There are both operative as well as non-operative strategies, as well as techniques to consider. What's impressive is the increasing number of individuals living over 70, and the fact that chronic subdural hematomas often occur with mild injuries in patients who are older, who are often also on either an anticoagulant or an antiplatelet agent. The most concerning is that the recurrence rate associated with chronic subdural hematoma surgery can be as high as 30%. This graph, which is a little bit dated, demonstrates both the increasing age of the population – the darker blue is up until 2012, when data was available for this paper – as well as the increasing incidence of both chronic subdural hematomas, as well as the aging population. More recently, this paper from February 2020 demonstrates both the increasing incidence of chronic subdural hematomas over the past decade, as well as trends both in operative as well as non-operative management. With regards to pathophysiology, certainly during my training, the thoughts behind the origin of chronic subdural hematomas were damage to bridging veins that then would leak into the subdural space, and then via alcoholic pressures, draw fluid into that space. This is from a 2017 Journal of Neuroinflammation, and it has a really nice summary regarding the concept of the origin of chronic subdural hematomas being a result of injury to the dural border cell layer, which results in inflammatory cells attempting to repair that layer, forming new membranes that activate both inflammation as well as procollagens and angiogenic factors, resulting in fragile vessels that then cause blood leakage, perpetuating the cycle of inflammation and membrane development. This is just a graph demonstrating some of the many cascades that occur once the dural border cells are injured. Most of these are pro-inflammatory or pro-angiogenic. When it comes to decision making, the first decision we're confronted with is that of observation versus surgery. Certainly if an individual has neurologic deficits or suggestions of elevated intracranial pressure or cerebral herniation, those individuals should go to surgery, and fairly urgently. For those individuals that are asymptomatic or minimally symptomatic, there are some options that we can discuss and consider, keeping in mind that overall mortality has a wide range when it comes to chronic subdural hematoma surgery, anywhere from 0% to 32%, depending on the authors, with a relatively low operative morbidity. Again, there are no guidelines associated with the management of chronic subdural hematomas. However, if an individual has neurologic deficits or worsening neurologic status, those individuals should go to surgery or have an intervention performed. Increasingly, we're all faced with individuals that are on an antiplatelet or an anticoagulant or some combination thereof. Up to 40% to 50% of individuals with chronic subdural hematomas may be on an antithrombotic agent at the time of presentation. Luckily, these are increasingly reversible, and certainly the fact that they are on an antiplatelet should not deter you from intervening, should they have a neurologic compromise. The question often arises, and we'll discuss this again, when should you resume anticoagulants or antiplatelet use? Early resumption is generally at this point considered within two weeks of injury or two weeks of presentation. Certainly during my training, one month in a normal head CT was considered early. More recently, the goal has been to resume antithrombotics to avoid the complications of thromboembolic disease in these individuals. When it comes to the use of anti-epileptics, we cannot transfer the data from the guidelines which are for severe traumatic brain injury to those individuals with chronic subdural hematomas. Currently, there are no guidelines with regards to anti-epileptics in individuals with chronic subdural hematomas, and very few of these individuals go on to have seizures. Looking at a variety of papers, looking at both the complication rate associated with anti-epileptics in older individuals, as well as the relatively low incidence of seizures in these individuals, there's currently no recommendation for anti-epileptic use in chronic subdural hematoma patients. When it comes to surgical decision-making, some considerations include the use of a burr hole versus craniotomy, the use of SEPs, that is a twist drill with suction, to irrigate or not to irrigate drains, and their placement, bed position. And then once we go over some surgical decision-making, we'll discuss some medical adjuncts, or adjuncts to surgery. The question often arises, burr hole versus craniotomy, certainly the results in terms of complications associated with burr hole versus craniotomy. In this paper from 2021, essentially similar, both in terms of recurrence rates, as well as, both in terms of recurrence rates, however, medical and surgical complications were more common in the craniotomy group. When the question arises about single versus dual burr holes, there seems to be no difference between the two. I was a fan of this subdural evacuation port system, or SEPs, when it first came out. It's helpful in individuals who are too ill to go to the operating room, and the nice thing about this system is that it can be performed at the bedside, in the ICU. The only downside to it is that it doesn't appear to result in comparable evacuation of the subdural fluid, and may be associated with a higher recurrence rate. Most recently, Hoffman, in 2018, looked at predictors of outcomes using a SEPs-type system, and noted that it was successful as a first-line therapy in up to 76% of patients, and noted that predictors of longer hospital stay were really related to the patient's underlying condition of worse neurologic grade, with a GCS score that is lower, or advanced age, in addition to the thickness of the chronic subdural collection. The question is whether or not to irrigate. There's some variability here. There's a Circus study from 2007 that noted no difference, whether or not there was just a burr hole with evacuation of fluid spontaneity versus irrigation. This is in contrast to this Japanese study that suggested that irrigation resulted in a lower recurrence rate, and then there's this other study from Malaysia, suggesting no difference between the two approaches. Personally, I'm in favor, and our group in general, irrigates the subdural fluid until clear, although the data regarding that is questionable. This UK study from 2009 addressed the question of whether or not we should even be leaving drains in place. The study had to be stopped prematurely because of higher complication rates associated with those individuals that did not have a drain placed. As such, we have fairly good data arguing that a drain should always be placed after drainage of a chronic subdural hematoma. Our practice is to place one drain. Our general approach is to leave it in for 24 to 48 hours, and then to remove it if either drain output reduces or if it looks like it may be a cerebral spinal fluid. There's this interesting study from Japan that addresses the question of where to place the drain. I don't think I've, before reading this paper, considered where to place the drain, and what their study demonstrates is that there's a significantly lower recurrence rate when drains are placed in the frontal region. This paper out of Ireland considers the location of drain placement either in the subdural space or the subperiosteal space. Interestingly, they had better outcomes at six months with subperiosteal placement of the drain. This was repeated in a multicenter trial that was published in 2019, again noting a lower recurrence rate when drains are placed in the subperiosteal space. This is a graphic representation of both recurrence rates as well as primary and secondary outcomes demonstrating that subperiosteal placement of drains for chronic central hematomas results in better outcomes. And certainly our own group is transitioning to this practice slowly. One of the questions that we haven't sorted out in our group and where I see a lot of variability is the position of the head after surgery. There are those in our group that want the head flat to allow for better drainage and then others that argue for a head of bed at 30 degrees given concerns in these older individuals of both aspiration as well as cognitive deficits keeping them flat for 24 or 48 hours. One of the earlier papers that addressed the head of bed position after surgery comes out of Iran in 2007 and here they noted a higher recurrence rate of 19% in those individuals whose head of bed was kept at 30 to 40 degrees after surgery versus 2% recurrence rate in those that were kept supine. They did not notice any, they did not note a significant difference in either atelectasis or pneumonia in these individuals who are kept supine. This is in contrast to an earlier study from Japan that randomized people to supine for three days versus sitting position post update one and here they noted no difference in outcomes or recurrence rates in either of those options. We'll shift gears now to consider medical adjuvants or adjuncts to surgical evaluation. Atrovastatin is one such agent that inhibits inflammation and promotes vascular maturation and as such it appears in this meta-analysis to have benefit with regards to recurrence rates in patients with chronic subdural hematomas and this is from a neurosurgical review just this year. The role of dexamethasone in chronic subdural hematomas has been controversial for many years with a variety of papers suggesting a benefit. This is one such paper from 2009 suggesting a resolution of chronic subdural hematomas with dexamethasone in those with no neurologic deficits or only mild headaches. There are a host of other studies out there suggesting benefit associated with chronic subdural hematoma use as an adjuvant to surgery with better outcomes such as the study from 2007. This paper from 2012 argues that preoperative steroids seem to reduce the recurrence rates of chronic subdural hematomas after burr hole evacuation without associated increases in complications. However, this most recent multicenter randomized trial from Peter Hutchinson and his group published in the New England Journal of Medicine just last year randomized 748 patients to placebo versus dexamethasone as an adjunct to burr hole drainage for chronic subdural hematomas and although they noted a lower recurrence rate in the steroid group of 1.7 versus 7.1 in the placebo group, they also noted worse outcomes at six months in those individuals who received dexamethasone. As such, at this point I would be cautious about administering dexamethasone as an adjunct to surgery for patients with chronic subdural hematomas. Other promising agents include tranexamic acid or TXA. This is based on data from the CRASH-2 trial which noted reduction in deaths due to hemorrhage in acute trauma patients that had received TXA. Certainly it's evolved to become part of our preoperative protocol for patients with complex spine surgery. It's also been utilized in chronic subdural hematoma patients as evidenced in this paper out of NYU from 2016 that looked at sub-strainage with TXA and noted less residual volume in those individuals who received TXA. There's this 2013 trial from Japan that also looked at TXA for chronic subdural hematomas. Interestingly here is they had 18 patients treated just with TXA, noting good resolution without recurrences in those individuals who received TXA. A few years ago I heard about this TRAX trial. I have not heard much more but it's a designed to be prospective multi-center trial looking at TXA versus placebo. Perhaps one of the more exciting adjuncts to surgery for chronic subdural hematomas is middle meningeal artery embolization. The thinking here is that these fragile vessels which cause inflammation and blood leakage can be embolized by or their their proliferation can be prevented by embolizing the middle meningeal artery. There are multiple small trials as well as associated meta-analyses looking at this. This trial by this meta-analysis looked at embolization versus conventional surgery and recurrence rates and impressively the embolization group had a much lower recurrence rate as compared to the surgical group as well as a lower complication rate. Another systematic review in 2019 and also 2021 noted a lower revision or recurrence rate in those individuals who underwent MMA embolization. More recent reviews of MMA embolization suggest low recurrence rates on those individual low recurrence and low failure rates on those individuals who need to stay on either anti-platelets or anti-coagulants. Additionally they note improvements in terms of clinical outcomes but not without complications. Interestingly there's a 0.6% risk of vision loss from MMA embolization in this paper by Khan et al. Shifting gears to risk factors associated with the recurrence, one of the more common ones cited includes hyperdensity of the hematoma on imaging. Individuals that present with elevated INRs or an abnormal coagulation profile. Also the thickness of the chronic subdural hematoma has been associated with the recurrence as well as this list that you see before you here. It's important to remember that often these individuals with chronic subdural hematomas are older and are prone to complications that have nothing to do with their chronic subdural hematoma but more with our interventions, specifically bed rest in an ICU or in a hospital bed associated with increased risk for pneumonia, urinary tract infections, malnutrition, pressure ulcers, DVTs and PEs. I'll wrap up by reviewing this survey that was recently performed questioning 443 neurosurgeons. This world map demonstrates the location of these neurosurgeons. A requirement was that they treat more than five patients per year with chronic subdural hematomas. What I find interesting here is just the variety of responses given and here you see that most neurosurgeons will opt for a double burr hole followed by single burr hole. There is some individual using a twist drill and then a smattering performing hemicraniotomies using dexamethasone, using TXA, atorovastin or ACE inhibitors. When it comes to indications for surgery the vast majority are associated with neurologic condition followed by hematoma size or failure of conservative therapy. When it comes to performing a post-operative CT scan the majority of neurosurgeons will perform one at some time. Our current practice is not to perform it routinely unless there's a clinical indication and when it comes to resuming anticoagulants almost half or more will resume them within three to four weeks. In conclusion chronic subdural hematomas are very common as you all know. The field of options is evolving with some exciting developments with MMA embolization as well as medical adjuncts. It's important to engage family as well as caregivers when making decisions regarding surgery in older individuals and critical care is very important for these individuals. Thank you all very much for your attention.

chronic subdural hematomas

neurosurgeon

epidemiology

pathophysiology

management strategies

surgical decision-making