Good afternoon, before we get started, just wanted to review some housekeeping notes with everyone. We're recording this webcast, so everything that is said and anything that we discuss from the chats will be recorded. Please everyone remember to keep your mic muted. We will be doing question and answer using the chat function. Please feel free to send chats during the talk, but we will try to address them all at the end. The tech support are available if anyone should have any issues during this speed. Thank you all for joining us this afternoon. I'm Dr. Beniel Krasna, I'm an assistant professor at Johns Hopkins University, and last year I did my Brain Injury Fellowship at Moss Rehabilitation with Drs. Michael Salino and Thomas Watanabe, and while I was there, we had identified and tried to help fix a gap that we noted in the workup and treatment of hydrocephalus. That's what we will be covering today. I will be giving the introductory portion, going over the physiology of cerebrospinal fluid and ventricles, the different types of hydrocephalus with a specific detail on the target for the medical medicine rehab physician. Dr. Salino will be going over the interventions and workup for patients to be referred over for surgery, and Dr. Watanabe will be reviewing the post-shunt management of these patients. For myself, I do not have any disclosures associated with this talk. To begin, the physiology of the cerebrospinal fluid, it is made in the choroid plexuses of all four ventricles at a rate of 20 milliliters per hour. Blood is filtered through the fenestrated capillaries that can be seen on the side here. Sodium ions are actively pumped in, so the CSF has a higher concentration of sodium, chloride, and magnesium, but a lower concentration of potassium and calcium. Unlike the plasma, the cerebrospinal fluid only has trace amounts of cells, proteins, and immunoglobulins. The pathway that the CSF takes after being generated in the plexus in the lateral ventricles, they combine through the intraventricular foramen into the third ventricle, through the cerebral aqueduct to the fourth ventricle, and from the fourth ventricle to the basal cisterns, the tentorial notch, and then down into the subarachnoid space in the spinal column as well as bathing the subarachnoid space above the brain. And it is here around the cerebral hemispheres that the CSF is finally resorbed in the arachnoid villi of the venous sinuses. At any given time, there is 124 to 150 cc's of CSF present throughout the system, and 20% of that is in the ventricles, 65% is in the cerebral subarachnoid space, 15% is in the spinal subarachnoid space. Per day, 500 cc's are made, which is an amount of about three to four times that it's turned over in one day. This high level of turnover highlights one of the important functions of the cerebral spinal fluid, namely delivery of nutrients and removal of waste. Additionally, the filtration that we just discussed through the fenestrated capillaries mostly regulates the ionic concentrations in brain tissue to allow for proper neuronal communication. The CSF also acts as a cushion between the brain and the skull, decreasing damage possible from impact, and the fluid acts to buoyantly decrease the weight of the brain from about 1,500 grams to 50 grams, thus reducing the potential for shear forces to damage vessels when the brain is pulled in a deceleration. Another important purpose of cerebral spinal fluid is balancing the pressure inside the skull. Given that the CSF exists within the skull, it's subject to the Fonio-Kelley Doctrine, so more or less cerebral spinal fluid adjusts the intracranial pressure, and is directly related to the cerebral perfusion pressure, being patient there, and cerebral perfusion pressure being mean arterial pressure minus intracranial pressure. So some definitions to go over in general. Hydrocephalus or water on the head, another term is ventriculomegaly, which is a little more specific, meaning the increased size of the ventricles. The current classification system is still based on that of Walter Dandy's dye studies in the early 1900s, which divides into communicating, where the path of CSF flow is intact, and non-communicating, where the flow is obstructed somewhere in the pathway. Within the communicating types of hydrocephalus, we have normal pressure hydrocephalus, which is going to be the main focus for the rest of this talk, an image on the top right here showing a patient who had prominent ventricles. With other slices, you'd be able to see that there is no obstructive lesion anywhere, and that all the ventricles are dilated, and the ventricles are large compared to the sulci, which is in contrast with the next type, hydrocephalus ex vacuo, seen in the middle here, where the normal sulci are seen, even with these large ventricles, and hydrocephalus ex vacuo is also known as compensatory enlargement of the CSF spaces, as that's the pathologic process that happens in this case, what appears to be encephalomalacia from stroke or brain injury on the right side with concurrent enlargement of the ventricles there. The other type of communicating hydrocephalus that is without obstruction to resorption is hypersecretion, where too much CSF is produced, either due to a papilloma or a carcinoma in the choroid plexus. Communicating hydrocephalus can also be caused by an obstruction to resorption at the arachnoid villi, whether it be blood infection or a congenital issue. The other group of hydrocephalus is non-communicating, again, something preventing flow somewhere in the ventricular system, the example in the bottom right there showing dilated lateral and third ventricles, and then scrolling down further, the fourth ventricle being of normal size, indicating an obstruction somewhere between ventricles three and four. Most likely causes in these patients are tumor congenital issues, as well as trauma, and these patients are generally treated by neurosurgery. So within the grouping of normal pressure hydrocephalus, there's actually additional breakdown to some authors. Typically, there's secondary normal pressure hydrocephalus, often caused by subarachnoid hemorrhage or intraventricular hemorrhage. Again, this would be a communicating hydrocephalus because of obstruction to resorption. These patients are separated out by a lot of researchers as their path, their responses to treatments and types of treatments are different than those with idiopathic normal pressure hydrocephalus. These patients often can be noted on initial imaging when they come into an ER, but sometimes can be noted several months or years after whatever their inciting event was. When there is a problem, it's usually noted from functional or mental status change. It needs prompt workup and treatment is generally with a shunt. So in contrast, idiopathic normal pressure hydrocephalus, which will be of this subset, our main focus, it has unknown cause, as per its name. There does seem to be some problem with resorption, and there seems to be a correlation with vascular risk factors. Given the associated with advanced age of these patients, some of the data seen from animal model research and the characteristics of the patients who have been studied, there seems to be some dysfunction with their vascular system, as well as issues with CSF flow and composition. And there are very variable statistics, and the prevalence estimates really range. Some of this is based on the variable age that is being looked at. So for instance, in this study by Isaacs, 10 out of 100,000 to 5,900 out of 100,000 was the range, and the higher end of that was when they were looking specifically at patients over age 85. So this form of hydrocephalus, idiopathic MPH, is the form that we were taught with the classic triad and the mnemonic of the three Ws, wet, wacky, and wobbly, patients having gait instability, cognitive dysfunction, and incontinence. That triad is due to the aforementioned vascular and CSF changes, as well as inflammation and hypoxia, but more specifically, it is thought to be due to ventricular swelling, putting pressure on specific areas of the brain, causing dysfunction of the frontal cortical basal ganglia, thalamocortical circuitry. And this idea has further evidence because drainage has led to improvement in cerebral blood flow in those areas, as well as improved symptoms. The cognitive dysfunction seen in these patients is frontal subcortical dementia. Patients have psychomotor slowing, decreased attention and concentration, impaired executive function, seen as problems with encoding and recall, as well as apathy. These images on the right here show individually the three parts of the triad where the dysfunction is seen most commonly, and also overlaying the three different types where those intersect. The cognitive centers seem to overlap with the issues with locomotion in the medial frontal cortex. The gait dysfunction these patients have is described variably as apractic, bradykinetic, glue-footed, magnetic, Parkinsonian, and shuffling. These patients walk with a decreased cadence. There is no true muscle weakness noted on physical exam, and electromyography studies of these patients show contracting of antagonistic muscle groups, which indicates subcortical motor control problem. On the right here is the localization for these patients to the frontal cerebellar limbic and basal ganglia regions. The locomotion issues seem to overlap with the maturation maps in the right anterior insula, as well as in the cerebellum. The incontinence issue that these patients have is a frontal lobe incontinence, and develops in the order of urgency, then frequency, and then general incontinence. So diagnosing this problem is difficult and has different guidelines that have been published. There were international guidelines in 2005, and the Japanese guidelines listed here, which were updated most recently this year. Those guidelines both include an age recommendation, the international being a little bit more permissive with patients down to age 40, the Japanese guidelines saying the cutoff is age 60. The Japanese guidelines reserve the diagnosis of idiopathic normal pressure hydrocephalus for those who respond to shunting, and they therefore say to use a concept of idiopathic normal pressure hydrocephalus when trying to say how likely the diagnosis might be prior to surgery being performed. So to begin with suspected, which would be anyone who comes in with either a clinical story consistent with or imaging showing ventriculomegaly. Possible would be a patient has a part of the triad that's not fully explained by any other diagnosis, as well as ventricular dilation without an obvious cause. Probable would be those same presenting signs with a normal opening pressure on a lumbar puncture, imaging with disproportionately enlarged subarachnoid space hydrocephalus, which we'll talk about in the next slide, as well as gait disturbance, the type we described earlier, or improvement of their symptoms after a CSF tap test and or drainage test, which will be further covered by Dr. Salino. And then, like I said, the definite criteria being they must respond to shunting. So as I mentioned, imaging is a big part of the workup for these patients. One of the two main criteria, the clinical picture, plus the imaging showing ventriculomegaly. The measurement of ventriculomegaly is done with the Evans index, as shown in this picture to the right. That is the largest width of the frontal horns taken over the widest measure of the inner table of the skull. A ratio of greater than 0.3 implies that it's an abnormal ventricle side, and in the top 20% of sizes for patients older than 70 years of age. The other imaging finding that was mentioned in the last slide, and is a core component of the Japanese guidelines, is DESH, disproportionately enlarged subarachnoid space hydrocephalus. These patients have tight high convexity and enlargement of the CSF spaces, especially in the sylvian fissure. This can sometimes be seen before any symptoms of the triad, and in these cases, some researchers would classify those patients as asymptomatic ventriculomegaly with features of idiopathic NPH, and is thought to be a possible preclinical sign. So that may be, you know, a patient who is imaged for something else has this finding and could be someone to be tracked for development of the classic triad. So there's a large differential, as can be seen on this table to the right in a review by Williams et al., of the differential and other causes for, you know, each part of the triad as well as some diagnoses that do also include all three of those. So it's important to define that triad issues are common in the elderly, gait issues are seen in 20% of patients over the age of 76, incontinence is seen in 38% of women and 18% of men, and dementia is seen in 14% of patients over age 70. So other diseases obviously have to be considered, and one of the most important is Alzheimer's, which is important because it's different than NPH in its treatment options, but also because it can co-occur with normal pressure hydrocephalus. Normal pressure hydrocephalus has low tau and amyloid biomarkers, so a patient could have a normal level when they're tested, and that would actually not be helpful in telling whether there's concurrent illness or one or the other. An elevation would indicate that Alzheimer's is present and make it very unlikely that NPH is at play, since that should really balance it out. Additionally, there's similar imaging findings with Alzheimer's and idiopathic NPH, but one thing that can sometimes differentiate these patients is anomia is specifically more suggestive of neurodegenerative processes than it would be of idiopathic normal pressure hydrocephalus. Parkinson's is another age-important differential, and for those patients, a dopamine spec scan could be done. And again, there are plenty of confirmed NPH patients who can have another comorbid issue that can further exacerbate one of the symptoms of the triad. All of this is just to highlight why we should care. This is a treatable form of dementia, and a caution is that that idea has led to the over-diagnosis of INPH because people want to be given the chance that their problem can be cured, but that has led to ineffective surgeries and unnecessary complications, and why the Japanese guidelines do use the definite diagnosis of INPH as only those who are shunt responders. But still, there's a large differential for these patients and the symptoms that they have. It's important for us to identify the patients who do have this diagnosis, especially as timing can impact their outcome, both in terms of their overall improvement and also in terms of how quickly they can improve. The treatment is surgical, as mentioned, the definite diagnosis being one who responds to surgical shunting. But physical medicine rehab physicians are uniquely placed to be better able to identify the components of the classic triad, especially better than some of the others who perform lumbar punctures and may not be performing a large tap test, which is what would be needed, as well as we have our close relationship with therapists, so we can better assess pre and post lumbar puncture and tap testing, how the patient responds. And lastly, we can have better close follow-up with these patients, even post-surgery, to identify any complications and see their overall improvements. And with that, I will pass on the screen sharing to Dr. Salino to talk about the further workup of these patients. And I'll mute myself so that he can unmute himself. Very good. Very nicely done, Dr. Krasna. Certainly, I want to congratulate you on your new position and really give you a heck of a lot of credit for creating the hydrocephalus program here at Moss. It was when Dr. Krasna was our fellow, he was rotating through the neurosurgery clinic when one of the neurosurgeons said, you know, I prefer these folks off to interventional radiology, but I never get a good answer. And Dr. Krasna took it upon himself and said, hey, maybe there's something we could do about that. And we'll talk about our program in just a second. So let me do a little screen share here. Whoops. Let me get the PowerPoint up. Excuse me for just a second as the air we are now we got it. Let me get back to the beginning. There we are. Again, welcome to the AAPMNR virtual conference. Hopefully in the not too distant future, we could do this live. As mentioned, my name is Mike Salino, I'm a physiatrist at Moss Rehab with Dr. Watanabe, and I'll be talking a little bit about the procedural aspects of hydrocephalus evaluation. These are my disclosures, nothing really off-label to discuss here, and nothing really specifically relevant to this talk. So my objectives for the next couple of minutes is to talk about the pre-procedural aspects of this evaluation, describe some pre-procedural and procedural considerations, and review some of the related techniques on how you execute this. So the two procedural options for hydrocephalus evaluation are a high-volume lumbar puncture, greater than 30 cc, equal to or greater than 30 cc, that will be abbreviated throughout the course of this talk with the initials LTT, and then the second technique is placement of a lumbar drain, also called external lumbar drainage, or ELD. That's where you drain 100 to 500 cc per day for a couple of days, where you can actually attach a pressure gauge and give your neurosurgeon some indication as to what the opening pressure, or not the opening pressure, but the pressure on the shunt should be if the patient does go on to shunting. And we'll go over both of these a little bit. So pre-procedural evaluation, you know, no one just gets set up for a procedure unless we review what we're doing. Review the referring physician's documentation and some traditional referring sources are shown to you there. Make sure that normal pressure hydrocephalus is in the consideration. Check the CSF analysis is also requested. This neurology wants some CSF analysis during the time when you're obtaining spinal fluid. It's not a bad idea to check beta-2-transferrin from the spinal analysis. Beta-2-transferrin is a CSF only protein. This will actually confirm that you're in spinal fluid and not some other space. Pre-procedural laboratory evaluation is not atypical for what we do for many procedures. CBC to make sure that folks aren't infected, a PT and INR for anticoagulation concerns, and a basic metabolic profile, specifically looking at kidney function in case you do want to inject any dye. In terms of historical perspective, you want to know if someone's had any lumbar procedures, including things like surgeries or fusion, any skin breakdown over the area, anticoagulation concerns as well as supplements that we'll talk about in just a moment. Decide on whether IV antibiotics are indicated. This is really only appropriate if you're doing an external lumbar drain. Decide whether you want to do intravenous or oral. If you are going to give antibiotics, not a bad idea to get an MRSA nasal swap that could help target antibiotic coverage, as well as a urine culture in case you're concerned about any neurogenic bladder concerns. The vast, vast majority of procedures can be done with just local anesthesia. Conceivably, you could use anesthesiology to provide a very light degree of sedation. We have not found that necessary here at Moss. There's a couple of different guidance techniques, visual palpation, fluoroscopy, and ultrasound. There is pretty good data in the literature to suggest that in terms of patient comfort, as well as patient safety, image guidance is recommended. I will tell you that I am almost exclusively fluoroscopically guided. I have dabbled with ultrasound guidance for lumbar puncture and don't have the same level of expertise as I have as fluoroscopy. I did not discuss that for the remainder of the course, but for those expert ultrasonographers out there, that may be something to consider. Get consent for the procedure, and specifically asking the question, given the concerns that normal pressure hydrocephalus could have cognitive impairment, can the patient consent for themselves? Review the nature of the testing with the patient, and most importantly, who's going to communicate the results? Some neurologists and neurosurgeons would like to be the person to report the results directly to the patients. Other referring physicians are fine if they want us to do it, but make sure you have a plan for that ahead of time. This is our procedure for LTT. We evaluate folks. We get an initial physical therapy evaluation. We'll talk about what the assessment measures might be. Then on the day of the procedure, the patient comes in and gets a short, usually a half-hour physical therapy session to establish an immediate baseline. They go on and get their LP, and then immediately after their LP, they come back and get a repeat physical therapy session, usually within an hour or so of the initial evaluation to see if there's any distinct change. For lumbar drain procedures, we do this as an admission. We have, again, a baseline evaluation, place the drain, and have ongoing assessments for the period of time where the drain is in place. Risk stratification, I would highly recommend for those individuals who are executing this procedure that you look at the American Society for Regional Anesthesia Guidelines in terms of risk stratification. A lumbar puncture is considered intermediate risk. A lumbar drain is considered high risk. This has implications on your anticoagulation management as well as other issues. It's a document you probably want to have at your fingertips if you are executing these procedures. Recognize that there is actually an emerging body of literature that suggests that stopping anticoagulations may have a higher morbidity than the risks of bleeding on anticoagulants. This is, for those of us who do procedures like this, this is certainly something that is a bit of a hot topic, and you want to keep up to date on the most recent recommendations. ASRA updates their guidelines every two to three years, and that's in Regional Anesthesia and Pain Management, the ASRA journal. So anticoagulation recommendations in general, always a good idea, and actually now considered standard of care to have a collaborative discussion with who prescribes the anticoagulant or antiplatelet therapy. If you're the one who prescribed it initially, that means you have a discussion with yourself, but if it's neurology or cardiology or someone else, you want to have that discussion and document it in your record. Medications that you want to look at include nonsteroidals, aspirin, antiplatelet therapies, traditional anticoagulations. Supplements by themselves usually don't cause any issues, but in combination with other medications, especially the nonsteroidals, you can have some prolonged bleeding effects. Document with the patient when they're supposed to stop the anticoagulation as well as when to restart. The next couple of slides will just go through sort of a laundry list of the current set of recommendations. I won't spend a whole lot of time on them. You can look them up yourselves and they will be retained for posterity, but just to give you an idea of the medications you could look at. Again, these are herbal supplements that have reported effect on bleeding, especially in combination with nonsteroidals. I'll be absolutely honest with you, I can never keep track of all the supplements and all the purported effects on anticoagulant therapy. I just tell patients to stop all supplements usually a week before the procedure so I don't have to remember exactly which one is which. Nonsteroidals, the list of the common ones are shown there and recommended days to halt. Notice that some of them actually go out beyond a week, so keep that in mind as you plan out your procedural schedule. Aspirin is an interesting molecule in terms of management. Standalone there's very specific recommendations. Make sure that, or take a look at to see if someone is on concomitant SSRIs or SNRIs, there's actually an increased risk of bleeding if someone's on both aspirin and one of those agents. For an LTT, you stop four days out for an external lumbar drain, six days out. Consider holding for one day after procedure, recognizing that there's a body of literature now that suggests hypercoagulable state after being off aspirin for a period of time. There are some neurologists and cardiologists who after being off for a couple of days will actually do a double dose of aspirin or an aspirin every 12 hours for a day or two to address that rebound effect. Again, that's part of the discussion. And again, weighing the risks of stopping versus bleeding is a pertinent point during this discussion. These are some of the antiplatelet agents, again, kind of talking about onset and offset of these medications. Coumadin and heparin, again, the recommendations are there for you, including coumadin, heparin, and low molecular weight heparin. Here's some more information, as well as the resumption time of the various agents. Some more of the newer anticoagulants. Infection control. Here's a table that does a pretty good discussion on what infection measures you should take when executing this procedure. Recognize infection precautions apply to both the patient as well as the clinician. Usually we're looking at gram positives if we are concerned about skin flora. Some individuals will do a double prep. The other thing to keep in mind is depending on what prep you're using, if you're doing any skin marking, which you'll see in a little bit, there's the potential for things like alcohol and chlorhexidine to wipe out your pre-procedure marking, and I'll show you that in just a second. So now you're ready to do the trial, you have the patient prepared, you should prepare yourself. There are standalone kits for both LTT and ELD. You might want to consider having additional spinal needles available for you, depending on patients, including some longer length needles or higher gauge needles to assist with the procedure in specific patient populations. So for the LTT, in the visual palpation technique, there's two options, one in a lateral decubitus or sitting position. Try to flex the lumbar spine in an effort to open up the interlaminar space. Generally the biggest issue with using the visual palpation technique is that you want to have the spine in neutral alignment with the hips and shoulders in a parallel appearance. This is a little bit easier to achieve in the sitting position than it is in the left lateral or right lateral decubitus, where sinking into the table is a very common occurrence. I'll be honest with you, I have very rarely done visual palpation. I almost always do flora. This demonstrates the relationship to the lumbar vertebra, to the iliac crests, and that you're going in between the lamina to the interlaminar space to achieve the lumbar puncture. So you mark the area, you can see a little blue dot there, and then you clean the area with betadine in this case, place a drape over the top of it. Anesthetize the skin and then begin the approach with your spinal needle. As you can see in the cartoon in the upper right-hand corner, the spinous processes are a little bit slanted cephalad to caudad. So you want to align the spinal needle so that you don't hit the inferior superior portions of the spinous process as you approach the intrathecal space. So you can see that your needle will actually be tilted a little bit. I tend to go a little bit off the midline or a paramedian approach. The reason for that is that you then get away from the interspinous ligament and the advancement of the needle is a little bit easier. You do want to try to stay parallel to the spinous process. Going off parallel gives you the concern of perhaps missing the intrathecal space as seen in the bottom right cartoon. Now let's move to the fluoroscopic technique. Similarly, there are two position options, lateral decubitus or prone. I tend to do prone. I think it gives you a little bit easier of procedural technique, although you do lose the ability to get opening pressure if you do it in the prone position. In the prone position, you want to put an abdominal pad as shown in this screen to help minimize the lumbar lordosis. So you position the patient in the prone position with an abdominal pad underneath. You then take a scalp film. The areas highlighted in yellow represent the interlaminar spaces. In this relatively young individual, you have a nice wide open interlaminar space to go for. You place a little bit of a mark on the skin. This is before prepped, and you can see the fluoroscopic image in the right-hand corner of your screen giving you a target approach. Then you go ahead and prep the area, again, prepping with betadine so that you keep your markings in place, drape the area around. You then use, again, a finder needle. Again, this is, I tend to go a little bit paramedium. It's maybe a little bit too lateral, but I keep it there for the point. Anesthetize the skin as shown here, both superficial and a little bit deeper. Then you advance your spinal needle. The spinal needle, the fluoroscopic image isn't perfect here, but you could see that you're angulated to avoid the spinous processes, and advance the needle and you will get spinal fluid as seen in these two images. I do have a video of lumbar drain placement. I'm actually going to skip this, and we'll come back to it if need be. We're running a little bit long on time. These are the assessment scales. Perhaps the best indicator is gait function, usually obtained within the first hour or so after the lumbar puncture. These are some of the other guidelines that are there for you. We've also found that the timed up and go, or the tug test, is a very good measure for both pre and post assessment. This is the IP, normal pressure hydrocephalus grading scale, as Dr. Krasna talked about, and the balance scale, as well as the gait scale. Again, these are good scales to have at your fingertips to do both a pre and post assessment. Response usually occurs within the first hour. There are some individuals who have a prolonged response. It's a good prognostic indicator. No response to a lumbar puncture does warrant further investigation. You may want to consider going on to lumbar drainage, as I'll show you in the next photo. The sensitivity for a lumbar tap test is only 60%, meaning that if you stopped after a lumbar puncture, you would miss a fair, or at least a chunk of individuals who might ultimately respond to shunting. There is some evidence that the higher volume of CSF that would draw has an impact, makes it more likely for you to achieve a positive test. So in conclusion, a kind of a whirlwind tour through spine procedures for hydrocephalus definitely can be profoundly beneficial. Lumbar drainage is a little bit more challenging, but can provide some more information. So I'm actually going to stop share now and then turn it over to my colleague, Dr. Watanabe, to talk about the next steps in our presentation. Great. Well, thank you very much for those good words. And I'm going to talk about what happens after the diagnosis and evaluation. So hopefully I have no disclosures, and hopefully have some renewed interest in searching these patients out after what you've heard, and now that you have them, what do you do? So I'm going to talk a little bit about how you evaluate efficacy right after the shunt, how you manage the shunts, complications that you might see, and anticipated outcomes. And we realize that some of you may not have the opportunity to do all of the diagnostic workup that has been described, but most of you will have the opportunity to care for patients with shunts at some point. So hopefully the information I share will be helpful in that regard. So let me start by just sharing a little bit of information of what you might expect to see if you see the patient soon after shunt placement. A couple points to make here. First of all, it has been demonstrated in a few studies that a delay in intervention may lead to a longer time frame for recovery, and that's what this graph shows. This is a study by Miyajima. They had two groups. So the first group received the shunt right away. The second group was randomized to receive it after a three-month delay. That's the group in red. And you can see that post-implantation, there's actually a delay in recovery here measured on the modified Rankin scale for those who were delayed, really highlighting the fact that it may be important to identify these patients early and be aggressive in terms of intervention. And this is idiopathic neuromotor hydrocephalus. As Dr. Krasna said, most of our discussion is focused on that. Something else to consider after the shunt has been placed is there are several studies that demonstrate little to no correlation between change in ventricular size and functional improvement for normal pressure hydrocephalus. So, getting imaging early may not be helpful in terms of evaluating what's going on there. Now, patients who get shunted for other reasons, a secondary hydrocephalus, that is not the case. Typically, what you see on imaging is helpful in terms of sorting out efficacy or not. When we talk about efficacy, we really need to think too about what sorts of measures we're going to have. Symptoms are certainly a guide in terms of sorting out whether a patient is responding nicely to shunt or not. I'll be having some other objective measures, some of which are the ones that Dr. Salino suggested can be quite helpful as well. Once shunt is placed, Dr. Salino did mention that there's the opportunity during the trial to provide, get some information that might lead one to have an idea of where to start in terms of setting shunt for those that are programmable. And I'll talk a little bit more about programmable or non-programmable in a minute. There are actually some published tables that take into account gender, height, and weight as a way to start. And here are some general guidelines that people might use. Starting at 12 centimeters of water is one. In general, as with many sorts of interventions, the strategy is to go slow. So start with a higher pressure and reduce that more gradually. The general recommendation would be to consider adjustments every two to three months, titrating for improvement. One of the concerns, if you're too aggressive in terms of adjusting your shunts, you may over-shunt, and we'll talk about that a little bit later. These images here show different ways that you can evaluate what the shunt setting is. So sometimes it's radiographic. As you can see in the radiographs, you can see where the shunt is set. Others have meters. These adjustments are made via magnet-based tools. So just remember, there may be some implications for MRI studies because of that, making sure that we haven't had a resetting of your shunt with an MRI. In fact, some of the industry recommendations are also making sure that you don't have strong magnets for work or even toys around as well, as they could lead towards some alterations in the shunt. Some complications. So the leading complications that we see after a shunt displace are obstruction and infection. These are relatively common early on, but you can also see complications late, even years after shunts. Late infections are often related to peritonitis, abdominal pseudocysts, or bowel perforations. The presentation of these complications is typically similar to the presentation for NPH in general. So you will see problems such as nausea, vomiting, headache. Generally, if fever is part of that picture, infection is way up on the differential diagnosis at that point. There is some controversy regarding the risks and benefits of tapping a shunt reservoir. So if you're concerned about fever, getting CSF would certainly be the best way to do so. And the reservoir is fairly easily accessed. So you may want to consider doing that, but there is certainly some risk of infection as that is a direct access to CSF. Generally, when a treatment is required for infection, it will involve removing the shunt. It's temporary placement of an EBD and then a prolonged course of antibiotics before replacing the shunt. Obstruction is the most common complication that is seen. Some studies do suggest that programmable shunts decrease the risk of obstruction. We'll talk a little bit about programmable or non-programmable a little bit later. Another issue with programmable shunts or advantages that they potentially decrease the, or they can perhaps do complications related to over-shunting. So if you have over-shunting, you can get clogging of the catheter and over-shunting typically is more common with non-programmable shunts. The presence of blood or blood products can also increase the risk of obstruction. And this is especially seen in certain secondary hydrocephalus conditions. Abdominal pseudocysts or CSF pseudocysts can occur. And when they do occur, the recurrence rate is fairly high, up to 25% in some studies. So sometimes surgeons will opt to move to a non-peritoneal position for that shunt. To evaluate obstruction, generally radionuclide studies are done. CSF infusion tests can also be done. These are more common in Europe. When you do a CSF infusion test, there are some reports that by doing the test, you can actually relieve some of the proximal obstructions at times. So you can, if you block the distal outflow when you inject doing an infusion test, you can sometimes clear the proximal blockage. If you're concerned about an intra-abdominal process, CT or ultrasound would be the way to go to evaluate that. Overdrainage, I mentioned that briefly before. This is another fairly common complication. The primary symptom with overdrainage would be headache. This generally comes on when a patient moves into a sitting or standing position and is relieved by lying down. The main way to address this is shunt adjustment. You may require surgical intervention. If it's a non-programmed shunt, you would certainly need to change that shunt valve out. There is a greater risk with more rapid reductions in shunt valve pressure, as mentioned before. And over-shunting can also lead to subdural hemorrhage, possibly related to traction in the bridging vein. So this is something that we do try to avoid. There is still some debate about the pros and cons of programmable versus non-programmable shunts. So I'll touch bases on that here. At this point, most studies do support programmable shunts as being more cost-effective. There are fewer issues with over- or under-shunting with programmable shunts overall, but no difference noted in the infection rate or catheter-related complication rate in some of the studies that I saw. At this point, some of the clinical guidelines, including the most recent one that I found that Dr. Presna also cited from Japan, give grade one level B evidence recommending the use of programmable versus non-programmable shunts. Remember that some of the programmable shunts, as I mentioned before, are MRI-susceptible, meaning you will want to make sure that there has not been any resetting of the shunt after an MRI. In addition to programmable and non-programmable valves, shunts can have an anti-siphon valve placed, which can help prevent over- or under-shunting also. We think of folks with normal pressure hydrocephalus and shunts as having chronic conditions. There is long-term longitudinal care that should be expected to care for these shunts. And some of the patients can be stable for many years before running into problems. You should also consider when symptoms arise that patients with BP shunts do have multiple comorbid conditions that should be considered. As I put this slide together, I was thinking back to patients with intrathecal bacterial pumps, which are also very chronic, long-term commitments. It's kind of interesting when a patient with an intrathecal bacterial pump gets sick, people always seem to want to blame the pump. With normal pressure hydrocephalus, especially in a more chronic condition, it seems that people often forget that the shunt is there and they think about more medical things. But of course, in both conditions, evaluation of the technology and the underlying comorbidities is important. PET-CT is usually a good first step in terms of evaluating whether there's a new problem, especially if you have imaging for comparison. If you're having specific symptoms for instance, intra-abdominal symptoms, you may want to get an ultrasound or a CT. And the image on here does demonstrate a CSF pseudocyst in the abdomen, which is causing much of the problems in this case. Outcomes. So broadly speaking, a summary of reported outcomes has this wide range, 63 to 84% in one year, 60 to 74% at three to six years. Remember, outcomes are of course impacted by patient selection. Dr. Cranston mentioned that early on, that you will get better outcomes with better selection of patients. Those who you're more confident do actually have normal pressure hydrocephalus. Outcomes are also driven to some degree by the choice of outcome measures. And then don't forget that there are factors other than the direct effects of the shunt that may impact outcomes, whether it's comorbid conditions or other things in that realm. Short-term outcomes, if you look at those studies, they're often impacted by surgical complications. Longer-term outcomes are often impacted more by the comorbid neuromedical conditions that many of these patients who have NPH will have. So in terms of outcomes, the AAN practice guideline from a few years ago states that shunting is quote-unquote possibly effective, which is not a real robust finding. But it did note that the studies that were not class four did demonstrate more improvement. So 96% chance for subjective improvement and 83% chance for improvement on a time to walk test at six to seven years. And then the study that did not show any improvement on a time to walk test at six months. That's more encouraging than just the quote possibly effective. Broader quality of life outcome measures have also been looked at to evaluate factors such as cost and overall impact on quality of life. And there's stronger evidence suggesting that intervention for normal pressure hydrocephalus can have an impact on cost and quality of life. Seriously adverse events, at least in the AAN practice guideline study quoted 11%. So of course, risks should be considered in terms of looking at outcomes. What about outcomes related to type of shunt? I've briefly mentioned that there are different types of shunt, although ventricular peritoneal is the most common. There was one fairly large study examining patients who received lumboperitoneal shunts compared with historical controls who had been enrolled just previously who had ventricular peritoneal shunts, same inclusion criteria, same outcome measures. And in this study, no significant differences in adverse events or serious adverse events was noted, but shunt revisions were more common in the group that received the lumboperitoneal shunt versus the ventricular peritoneal shunt. Here's another study looking at outcomes related to shunt type performed by Chirinan. Overall efficacy and rates of complications similar in this systematic review for all types of shunts. Some vascular risk factors are thought to be associated with the development of NPH. Some of these vascular risk factors are actually also psychosocial, not just diabetes and hypertension. So it's interesting as we look at outcomes to see some of these other comorbid conditions and the effect that they might have. And so one of the most important predictors for low quality of life in this study in patients treated with shunts was coexisting depression. Another highlight of this study, I think, is that when comparing NPH with other dementias, NPH actually seemed to have a higher impact on quality of life than Alzheimer's disease, about an equal impact with Parkinson's disease. And this highlights to me why intervention can be useful and is important and why we wanted to put this talk together. Severity of pre-shunt symptoms, and this is related to what I mentioned before, to some degree, the timing and intervening sooner than later also impacts the effects of the shunt on post-procedural quality of life. Finally, cognitive outcomes. So the rates of cognitive improvement, if you look at the studies, ranges from zero to 80%. By itself, that number is not very helpful. There are multiple reasons why there's a wide variation. Similar reasons that we have for interpreting other studies. Duration of symptoms, comorbid conditions, patient selection, and choice of outcome measures. Nevertheless, other studies have demonstrated significant improvements in cognitive function. A meta-analysis by Peterson here demonstrated improvements in memory, global cognitive functioning, and psychomotor speed, but not executive function. All right, so here are some references for my part of the talk. And in summary, for all of us, hydrocephalus is an important and potentially treatable neurologic problem that can have significant outcomes. Early diagnosis and intervention can improve outcomes. So if we can avoid delays in identification of patients and intervention, that will be important. Physiatrist intervention can improve outcomes, Physiatrist can play an integral role here in identification of potential patients, performing the definitive tests to assess, being involved in pre and post-test assessments, and the longitudinal long-term management of patients after shunt placement. Not just managing the shunt, but of course, overall functional goals and outcomes. Robust improvements as assessed in a number of different ways can be expected and provide support for our efforts to identify and treat patients with normal pressure hydrocephalus. Thank you. Very good, Dr. Watanabe and Dr. Krasna. We have about four minutes left, so I'm gonna pass on showing the video and answer some questions. Dr. Krasna and I have been answering some questions on the side while Dr. Watanabe has been asking. If you do have a question, please put it through the chat box. I would like to thank both of my colleagues for doing an expert job in this. Please fill out your evaluations when you're doing your CME. If there are items you would like us to include or do a little different approach, please let us know. I'm gonna be respectful of people's time to keep the Academy schedule fluid. Thank you for attending. I'll stay on for the next three minutes to answer any questions that may come through the chat box. Just to answer them, there were some questions about do we do this for disorders of consciousness? And the answer is yes, although the assessment measures are obviously a little bit different. There were some questions about referral. Do we share a clinic space with neurosurgery? Do we see the folks concomitantly? We haven't evolved to that yet. That would be a nice undertaking. For the most part, it's been sequential, meaning neurology or neurosurgery refers the patient and then we do our thing. Interestingly, both neurology and neurosurgery, at least in our home institution, has been perfectly acceptable for us to share the results rather than sending them back to the referring physician. And then I just pulled this up, as Dr. Salino mentioned, we were trying to answer some of these questions as they came up just in the interest of time. But again, these are the cognitive assessments that were mentioned in the most in some of the literature, the MPH scale that was in Dr. Salino's slides, again, including these sections. So if you want to look that up by Hillstrom et al, and then the Japanese guidelines listed them more as a subjective scale, in addition to the other measures. So not the primary way to measure whether someone would be a tap responder or what their response is, but just as another assessment that can be done. Well, I'm going to close the session at this point. We have one minute left in the session. Everyone have a great rest of an Academy meeting virtually, and hopefully we'll see each other, all see each other all live next year. Dan and Tom, thanks so much. Thank you all. Take care.

hydrocephalus

workup

management

normal pressure hydrocephalus

physiology

pathophysiology

diagnostic workup

shunts

complications