All right, I want to go ahead and get started. Hold on, we're having some technical difficulties. I want to go ahead and get started. Welcome everybody to AAP Virtual Didactics. My name is Sterling Herring. I'm a PGY3 at Vanderbilt. We're putting these together for a variety of reasons. We're glad you're all able to join us today. First and foremost, every day we want to recognize and respect the people that are particularly affected by this pandemic. We know some people have been really affected and for others it's been less personal. We recognize and appreciate those of you who have been more involved than some of the rest of us. Again, our didactics, the purposes of these are to kind of augment the didactic curricula that are going on there at your home institutions to offload overstretched faculty and kind of help with some of the logistical disasters that have come as a result of this pandemic, to provide additional learning opportunities for off-schedule residents, again, some of the scheduling difficulties that have occurred, and then to develop further digital learning resources and to support all physiatrists during this COVID-19 outbreak. Housekeeping things. We're going to keep people's video and audio muted with the exception of the speaker. That's just to kind of help with noise, but also distraction and bandwidth. If you have any questions, please send them to me via chat. You can kind of, you click on participants and you'll see a list of participants and you can see my name is Sterling Herring, should be up near the top somewhere. Send your messages, your questions to me and as time allows and kind of where appropriate, I will ask Dr. Schneider. If you have any bigger questions, suggestions, concerns or anything, you see Candice's email there. Track us down on Twitter as well. But without further ado, we're going to move on to Dr. Byron Schneider. He is the fellowship director of the NAS recognized Interventional Spine Fellowship here at Vanderbilt, among other things. He's also very well published and an excellent speaker on a variety of subjects. So I know I'm looking forward to his talk today. Thank you, Dr. Schneider for joining us. All right, so thanks for having me. You know, I'm glad there's so many people, it's too bad we can't make it a little more interactive. So this will be mostly just a lecture. That being said, what I really hope to convey to you guys today is that there are, you know, thought processes on how to think about these things. And as you go through or complete your residency, I think it's really important to start to develop kind of skeletons in your head on how to hang facts on instead of just trying to memorize things. And it'll really make it easier as you go through to add to that skeleton of knowledge as you go through your training and you can prune it and add to it, but you have to organize it in your head. So hopefully this talk gives you not only important information, but a general framework on how to think about some of these things. I'll also like to quickly point out, as I assume this is mostly residents on the lecture today, I would encourage you all to get involved in the AAP in some form. If you didn't mention it, Dr. Sterling Herring who is hosting this is a resident himself and there is a large and good number of opportunities to get involved with the AAP even as a resident. So I'd encourage you all to do that. So as I pull up my slides here, we'll get started. And we're going to go over the risks and complications of spine procedures. There'll be a bit of a focus on epidural steroid injections. And then even when we talk about epidural steroid injections, we're going to really hone in on cervical epidural injections to start because it provides a good framework on how to think about these things. It's not a CME talk, so these are even less relevant. So the first thing we're going to talk about is we need to define these things, right? So what's the difference really between a side effect or an adverse event or a complication? And for one, neither imply wrongdoing, although wrongdoing can occur, but we all experience this otherwise. So for example, if I give you steroids, whether it's a pill, an injection, intravenously, I am in all likelihood going to raise your blood glucose levels if you're a diabetic. Is that a complication of the steroid or more a known side effect, right? And that's different. That's not only unavoidable, that's expected. And sometimes we use side effects for benefit. So for example, I like to give Flexeril in my clinic, but not because it's a good muscle relaxer, but because it's sedating and it'll help people sleep and I'm giving it because of the side effect. To contrast this, there are adverse events, which at times are complications. Some of these are avoidable, some of them are not, but they're certainly not routinely expected, right? So if we're talking, for example, an insufficiency fracture because you've gotten steroids too many times over the course of your life, well, that's an adverse event that you've experienced harm and it's iatrogenic, right? It's because of the care you've received and it's certainly not intended. So that's an adverse event. The other thing to slightly consider when you're going through these is the severity of them, which this will be broken down in severity. But some things, for instance, you can read a paper on spine procedures and see that the complication rates are like 20%, but they might include things like procedure-related pain or that there is vascular uptake or like bleeding, which may have just implied they had to put a Band-Aid on. Well, of course, if I'm sticking a needle in you, it's going to hurt a little bit. It shouldn't hurt a lot, but it's going to hurt a little bit. Is that really a complication, right? So how we measure these things and how we define them is really important. The overall structure of what we're going to go over today is really talk about the major complications from epidural steroid injections, which obviously are bad. That's why they get the attention, but in reality are exceedingly rare. And if you do everything properly and if you have a bit of luck, you'll hopefully never see them over the course of your lifetime, even if you do a large number of these procedures. And then we will shift gears a little bit and talk about the things that are more common and really break them down into things that are related to the procedure itself, i.e. sticking a needle in near the spine versus things that are almost secondary. So for example, because you're getting steroids, that has nothing to do with that it's an epidural steroid injection. It's just because you're getting steroids and break down the more common adverse events or side effects that way. So when you look at cervical epidural steroid injections, and like I said, talking about this, whether it's in the cervical or the lumbar spine, the principles are the same. So just use this framework to build your understanding. But in terms of cervical injections, there's over a quarter million of them done five years ago, right? And that's just in the Medicare population. So we're talking there's large, large, large numbers of these. So even things that have a rate of one in 200,000 are going to happen on an annual basis in this country. And also realize that while things change from year to year, interlaminar injections, which there'll be a diagram here to describe what that is for those of you that may not know, are a much more common approach to doing cervical epidural injections relative to transforaminal injections, which is just placing the needle in a different spot. So a cervical transforaminal injection, for those of you that may not know, it's really sticking the needle through the front of the neck. So it's an anterior oblique approach, and you're trying to get medicine into the epidural space within the posterior inferior foramen. So you can see in this nice picture here, the needle is at the bottom and the back of a neuroforamen. And hopefully you recognize here, the vertebral bodies are quite prominent, suggesting that we've just obliqued off of an anterior view. This approach does pass the needle within close proximity to a number of vital vascular structures that feed the central nervous system, and that's in all likelihood why this is not done as commonly and certainly why it's probably fallen out of favor until more recently again. But as you can see here, if you introduce the needle into the foramen, and this is an AP view now, you can get nice medication flow along the targeted nerve route and up into the epidural space. About 15, 10, 15, 20 years ago now, we started to get reports of serious complications from this procedure. And that undoubtedly is why the pendulum swung towards going back to interlaminar injections. Because for a while, a transforaminal injection was really considered the safe thing to do, and it became much more prominent. But as you can see here, there were multiple, multiple case reports of people getting strokes, people being paralyzed, some people even died, right, and that's bad. You don't want that to happen to your patient when you're doing an elective procedure just because their neck and their arm hurts, right? You don't want people to be dying over this. And while there was some debate for a while, it really became clear as to why this was happening. And it really occurred because there was inadvertent injection, right? So that's a, that's a complication in the sense that the physician probably missed something, or at least if today this happened, it would be missed because you know you should be looking for it. And you're injecting particulate steroids, so that's the white chunky kind, right? Kenalog, beta-methadone, depo-medrol, these steroids where you can visibly see the chunks in them. And you put it into an artery that, that comes through the foramen and then feeds the brain stem. And it causes an infarct. It's the same type of embolic infarct that you get in the brain when you get a little chunk of plaque breaking off your carotid artery, right? So the chunk goes until it hits an arterial where the diameter of the arterial is smaller than the chunk of steroids that occludes it and then whatever vascular territory that feeds if there's no other supporting vessels and parts. And this is not, not to be ignored when you're doing a cervical transfer amyloid injection, because when you're doing these, there is a very good chance that your needle is passing within just a few millimeters of a vital arteriovascular structure. So in this one study where they dissected cadavers, 21 of the 95 foramina dissected, your needle passed within either one of the large arteries in the neck or within a radicular medular artery that was feeding through the foramen into the spinal cord, right? So you cannot do this based on the assumption that complications are rare because the arteries aren't there. So you take that, the fact that you pass within these vascular structures that are potentially dangerous with the fact that back then we were almost always injecting particulate steroids, which are insoluble and they're large. We're talking 50 to a hundred micrometers and when you compare that to a red blood cell, which is only six to eight micrometers, it's very easy to see how these are going to clog up the vascular system, right? Most of us probably even remember seeing videos when we were in medical school of how a red blood cell has to squeeze through the capillary to get through. So you take something that's 10 times larger than that and it's just not going. You're going to clog up the vascular system. Beyond that, beyond this being theoretical, we've proven it in animal models. So you take poor swine models and you'd inject them with methylprednisolone right into the vertebral artery and lo and behold, they all got strokes. And they did this in a number of other animal models as well, including rats where you inject our particulate steroids into an artery going to the brain or the spinal cord and it infarcts. And it happens all the time in terms of within the experimental model. That really led us to what now hopefully is commonplace to you all, which is using dexamethasone for these procedures. So dexamethasone is only half a micrometer in diameter, which is 10 times smaller than an RBC. It does not regularly speculate or cause red blood cells to aggregate. So the other mechanism of injury thought to be related is that the steroid itself doesn't cause the embolism, but it causes red blood cells to clump together. But fortunately, dexamethasone does not do that either. And similarly in animal models, when you inject dexamethasone into these vital arteries, nothing happens. So now we have something that makes sense scientifically and is proven in animal models and readily explains all these case reports we receive. So if you recall the slide I just put up a few slides ago about all the cases of stroke and paralysis that occurred in the early 2000s, since we've switched to dexamethasone, this is a comprehensive list of neurologic complications from cervical injections done with dexamethasone. And given that we're doing probably a million of these a year in this country, and we've been using dexamethasone for five years or more now, we probably anecdotally have a very large N without a single case report of complications. So the transition to the steroid has likely made this procedure exceedingly more safe than it was when it first started. Because of this strong foundational theory in animal models and now experiential evidence, the guidelines that came out are very clear in what they state you should be doing. And that is dexamethasone is the only steroid that you should ever use for cervical transforaminal injection. There's no ifs, ands, or buts. And just to parlay that, because this lecture really isn't just about cervical epidurals, there's a similar recommendation for lumbar epidurals, which says that dexamethasone should always be the first steroid used, and that if a particulate steroid is to be used, it's really only under extremely rare circumstances, and that if you do use particulate steroids in particular, but really even with dexamethasone, there are a number of safeguards that you should be doing to ensure that you don't accidentally put medicine into an artery. And that really, that's a procedural, that's not a complication, that's a technique lecture, so we don't go into it, but needless to say, there are a number of things that you need to be doing to make sure that you aren't inadvertently injecting an artery. If you contrast this with an interlaminar injection, right, so now if you look at this diagram here, where this is the ventral aspect and this is the dorsal, you're now taking a needle and you're passing through, you know, posteriorly or maybe a parasagittal, you're going in between the lamina, that's why it's an interlaminar injection, through or maybe around the ligamentum flavum and into the epidural space. What I'd like to point out here is if you look where this needle tip is, this is surrounded by rigid structures, right, ligament, bone, CSF isn't really rigid, but if it compresses, you get to a spinal cord, which is relatively rigid, and this is the point of least resistance, versus if you look at the neuroforamina here, on the front where the artery is, there's this nice big area where the spinal nerve and the arteries are, that's really a pressure relief valve, so this is a much different area in terms of the pressure dynamics involved. And not to mention if you do a transforaminal injection, I don't know if you can see my mouse or my cursor up on the screen here, but your needle is centimeters away from the spinal cord, versus you can see with the interlaminar approach, you're millimeters away from the spinal canal, so you're now in a much more rigid space and you're much closer to vital neural structures. When you think about ways that you can get into trouble with this procedure, I should have had another slide here to break this down for you, but we can just do a thought process. So what, based on how I set this up, what do you think the ways are that you can get complications from this procedure? Well, one would be you put the needle too far, right, sticking a needle, especially a big needle, into the spinal cord is probably not good, and then if you inject medicine directly into the spinal cord, I can assure you, that is not good. And secondarily, if you inject medicine and then something happens, like bleeding, and it occurs, which is a space-occupying lesion within a rigid structure, it's going to expand out towards the spinal cord because it has nowhere else to go. So we're going to talk about both of those potential complications. So what happens if you stick the needle too far? Well, if you're lucky, you're going to be intrathecal, right, you got through the dura but not into the spinal cord. And if that happens and you detect it on fluoro, and that's happened to many of us, if you do enough of these, it's not a big deal, really. I mean, you might get a spinal headache, you've essentially done a lumbar puncture in the spine or in the cervical spine, but not all dural punctures even result in spinal headaches. So you can catch this and make sure it's stopped and no further harm is done. Now, if you detect intrathecal injection after you detect it via contrast, and specifically iodine-based contrast, which is the contrast most of us use most of the time, nothing's different, right? Because iodine-based contrast is safe in the thecal sac. In fact, that's what we use to do myelograms. Now what happens if you're using gadolinium, which is still done, not uncommonly, and hopefully by the end of this talk, you'll realize should never be done anymore, especially with interlaminar injections. And that's because if you inject the gadolinium into the CSF, you can get encephalopathy seizures or even death. And that was reported as far back as 10 years ago, but there's now been additional case reports within the last few years of people dying with only a CC or less of gadolinium in the intrathecal space. So that's bad. What happens if it's undetected, you put contrast in, you still don't realize it, and you put medicine in? Well, if you have any medications like steroids that have any preservatives in them, you may cause arachnoiditis, and you're in the cervical spine. So if you put a lot of lidocaine intrathecally, you are going to block, quote unquote, the cervical spinal cord, which I can assure you, if you put enough lidocaine in that part of the spinal cord, it will cause someone to stop breathing, which is not fun. What if the needle goes even further, right, so you're through the dura, and now you're into the spinal cord? Well, if your patient's awake, they're probably going to scream and say, ow, and you're probably going to pull the needle back. But unfortunately, a lot of these procedures are still done with sedated patients. And when that is done, if you stick a large needle in the spinal cord, and they don't yell ow, and you keep going, that can paralyze them, which is obviously not good. Even if you don't inject medicine, even if you just take a large needle and essentially bump the spinal cord, it can cause a contusion, right? Essentially you get bleeding within the spinal cord, which we all know from our spinal cord injury rotations, that bleeding within the spinal cord itself can cause problems. And then if things get really bad and you put the needle in the spinal cord, you don't realize it and you inject a large amount of medication such as contrast, now you're really going to cause injury. There are ways to mitigate this. So five years ago now, there was this new technique to do an interlaminar injection where you go from kind of the side and behind. So we call it contralateral oblique. And you can see here, you get very nice pictures and you can walk the needle up very closely and have a very good view of this. Versus if you look at picture seven and eight, that's a true lateral and that's what we used to have to deal with. And you can see how much harder it would be to gauge where your needle is within the spinal canal from the old technique versus the new. So we can mitigate some of this risk. I will contrast that with space occupying lesions, which we can minimize or probably not prevent with 100% certainty. So epidural abscesses, while rare, do occur. They present with pain and fever. They do not present with paralysis. And if you don't catch them, they will eventually become paralysis, right? So if you're in a spine clinic and your patient's calling you and it's a week after their procedure and their neck or their back hurts and they have a fever, you need to get them scanned. So if you have an abscess, you can treat it before they become paralyzed. And really the risk of this is probably minimal if you're using proper aseptic technique and all of those things, just like you would for any other delicate procedure. This is really the boogeyman though for all spine procedures that are interlaminar injections, whether in the cervical or thoracic spine and even in the lumbar spine. And over the next few slides are various reports that are documented in literature, case report or cohorts of epidural hematomas that occurred when someone was on or had been on and taken off various medications that mitigate your risk of bleeding. So things like aspirin, NSAIDs, clopidogrel. And you'll see here, I'm gonna scroll back and forth. Most of these involve something as benign or what is thought to be as benign as NSAIDs. So indomethacin, diclofenac, in this case they're on clopidogrel, but it was held, right? So even just messing with the platelets probably increases your risk of hematoma. There are a variety of guidelines that again are a little bit beyond the purview of this talk that go over on how to manage the risk of bleeding for spine procedures. But I would like to point out for the trainee's benefit, for everyone on this lecture, that while this is generally cited as the primary guidelines on what to do for these medications before procedures, this is all based on expert opinion and is not a review of the evidence. So it's guidelines, but that's all it is. It's not a systematic review. And I'll contrast that with another document that's been published that is a true review of all bleeding and thrombotic complications that occur when you're doing these procedures, when you keep people on or take them off if there are any platelet or any thrombotic medication. And I think that's really clinically what's important. And this is why it's important. It's really easy to say, it's very easy to say, you are on aspirin, I'm gonna take you off of your aspirin for your spine procedure so you don't get a bleed and therefore you won't get a hematoma, you won't get paralyzed and I won't get sued. But there is a total other side of the coin to that, right? People are on these medications for a reason. If someone is on warfarin because they had a DBT or a PE and you take them off of that, they might get another one. And in this Sentinel article that largely comes from a study by Andres, it is very clear that if you take patients off there any coagulation prior to these procedures, you will kill people. And you will see here that a number of injections, interlaminators and others where people on warfarin for their AFib had strokes and heart attacks. So it's not quite as simple as just saying we wanna mitigate the bleeding risk. It actually becomes a much more complicated topic. And needless to say, that is a talk in and of itself. So we're not gonna go into it any further. But if you want, you can reference these papers and teach yourself a little more about it or look out for a talk at a conference here where we go over this in detail. I would also like to point out shifting gears a little bit that paralysis from other spine injections, you may be thinking, gosh, the title of this was complications of spine procedures and all we're talking about is epidurals. Well, that's because if you're doing any other sort of spine procedure, you should not be paralyzing someone because if you do that procedure properly, the risk of paralysis is theoretical at worst. And probably theoretical only in the sense that it could only occur if you do it wrong. So the risk of major complications from other procedures, so a facet injection, a medial branch block, even a radiofrequency ablation, if you follow proper technique and proper safeguards, the risk of paralysis is zero or near zero. Fortunately, this goes a little bit beyond theory because we have a number of very large cohort studies that document this. And again, from a learning perspective, especially for residents, you can't say, oh, there's no case report, so it's safe. You certainly can't take a study that enrolls or looks at 100 or 200 or even 1,000 patients and say procedure X is safe, right? Because if the rate of a complication is one in 5,000 or one in 10,000, the chances of you detecting it in your study of 100 is statistically improbable. So to truly be able to comment on the risk of these procedures, you need very large studies and cohorts, right? You can't do a randomized study on this stuff. You just need to collect data on all the procedures done. And fortunately, over the last five years or so, we've started to really develop this body of literature. So this is one of a few studies that came out from the US that was really a collection of safety data at RIC and at Penn and at Stanford. And they collected and combined all of their complications data. And when you started looking at really large numbers, so 26,000 spine procedures now, there's not a single case of major complication, no paralysis, no hematoma, nothing, right? So while these complications exist and they're serious and they're scary, if you do things the right way, they are rare. Even minor complications are occurring at a very low rate, one or 2%, and these are the things we will soon go into for the rest of the talk, right? So the most common quote unquote complication from these is probably just someone feeling like they're gonna pass out. And even that's only at a rate of one to 2%. Interestingly, that is also the most common reason for you have to stop these procedures is vasovagal reactions. Although there are other reasons you may have to stop these procedures, including getting into large vessels that you can't just get out of or if patients hurt. And obviously aborting procedures is suboptimal, though sometimes it is the safest and most appropriate route. I'd also like to point out that in these large, large studies now of 25,000 or more patients, even things that are sort of serious, so things that would prompt an emergency room visit are less than one in a thousand. And that really comes into these things that may or may not even be related, right? An allergic reaction, probably related. Chest pain, probably not. If you just look at 26,000 primary care doctor visits, I'm betting they've had to send one or two patients to the hospital because they have chest pain, just because they were unfortunate enough that they had their heart attack at the doctor's office, right? So sometimes you'll get complications that occur during your procedure that are even unrelated. I think even if I recall a couple of years ago, I had a patient whose heart rate was extremely high during the procedure. And we stopped the procedure and sent them to cardiology, and it turned out they had undiagnosed AFib, right? So the procedure didn't cause AFib, but in a way that would get documented as a complication that occurred during the procedure. This is a similar study from the same group of physicians looking only at epidurals, so not all spine procedures, but just epidurals. And we get very similar findings, right? So no neurologic injuries, no major bleeding, no major infections, and a complication rate of 1% or less that mostly involves vasovagal reactions. And again, some rare emergency room visits, nine patients out of 16,000, mostly related to pain or delayed allergic reactions. And interestingly, people argue which injection is more painful, but at least in this report, there was really no difference in pain, whether it was an interlaminar or a transforaminal injection. And even more interesting, of the patients who had to go to the emergency room within 48 hours of the procedure because their pain was worse, many of them, it was just because they re-herniated their disc, and again, it had nothing to do with the procedure. Again, the most common minor adverse events, which we'll go to in more detail as we conclude our talk in the next 10 or 15 minutes, are things like vasovagal reactions, intravascular flow, and pain. So that was a large study from the US, it was 26,000 patients. I believe this is a Korean study, and they outdid us. They looked at 26,000 patients. Again, they didn't really outdo us, they tied us. They found some slightly different outcomes because they were looking at ER logs outside of the procedure logs, and they found a few complications, including four infections and two hematomas. But note that that's a rate of major complication of less than or about 0.01%, right? So that's one in 10,000. And that is the rate, I will quote my patients if they ask what the chances are of a serious complication is one in 10,000. And if you think about that, I don't know where everyone's from or where you drive, but I would guess that in Tennessee, your risk of getting a major injury just driving to my office is higher than one in 10,000 when you put together driver skill and road conditions. So it is probably more dangerous to drive to the hospital than it is to get the procedure, assuming that the proceduralist that you're under the care of knows what they're doing. There were some other procedural related complications in this large study, again, of 26,000 patients, but know a lot of these were related to the steroids, which we will talk about. So GI symptoms, aggravation of their psychological underlying conditions like bipolar, elevations in their blood sugar or blood pressure or an aggravation of heart failure. And really that is pertinent to the procedure because you gave them steroid, but it's not pertinent to epidural injections, it's pertinent to steroid injections. And it really holds true to whether you're doing a knee injection, shoulder injection or a steroid dose pack. And in reality, some of these steroid side effects because they're really the most prominent cause of complications outside of vasovagal reactions with these procedures are why I tend to limit how many oral steroids I give, right? Because if the risk of me doing an epidural steroid injection is largely tied to the risk of the steroid I'm giving you, but I know based on good evidence that the likelihood of an epidural steroid injection in the right patient is much more likely to help than oral steroids, I'm going to reserve those risks of steroids to when I really need them. And I'm only going to expose my patient to those risks when the risk benefit is more favorable, right? When I'm giving them via a means that is more likely to help. I think that's very important to realize that steroids are probably the most dangerous part about these procedures, at least when we're doing epidurals. So more numbers just to drive home the point here that the risk is about one in 10,000 and that the risk of major complication is even less. Hematoma was two out of 52,000 and infection is one out of, or four out of 50,000. So collectively based on these large, this is evidence-based, this is not expert opinion, this is not anecdotal. Clearly there are major complications, but it is also very clear that they occur at an extremely low rate. And some of the hoopla that has surrounded spine injections over the last 10 years is probably a little bit blown out of proportion. Do people get paralyzed from these things? Yes. Is the risk of that occurring if it's done properly high? I think the answer to that is unequivocally no. So these are the other things which I've hinted at, but we'll go into with a little more detail. These are things that could go wrong during your spine procedure, but they're not death, they're not strokes, they're not paralysis. These are things you can deal with. These are things that your patients will understand. These are things that are inevitable. And because they're inevitable, even though they're not serious, you need to understand these because these are what you are gonna run into on a day-to-day or week-to-week basis. So the first thing, because it's probably the most common adverse event during a spine procedure is vasovagal rates. We looked at over 8,000 procedures and found that the vasovagal rate was about 2% to 3%. But even more importantly, I think, and is this the bottom part of the slide here, is that these are way, way, way, way more common in young men. So the old stereotype of like the woman that needs the swooning chair because life is just so hard and she's gonna pass out is totally untrue. It is your Navy SEAL that comes into your clinic for an epidural who's gonna pass out on you. And you really need to change your mindset of who you need to be worried about these things on. We looked at these things in a little more detail and I do think it's worth pointing out that for one, if you give sedation, which I do not think should be routinely done for these procedures, but if you give sedation to these people who have passed out before, their risk of passing out again is almost negated. Their risk of a repeat vasovagal is 20%. The risk of repeat vasovagal sedation is zero based on this one study. And not to poke fun at you guys and certainly not to say that you should not be involved in these procedures. But interestingly, we found that the rate of vasovagal is significantly higher when trainees were involved in these procedures. And to be honest, we weren't quite sure why, but it was not a statistical anomaly. Now we're gonna talk about things that can occur. A vasovagal occurs just because you have a needle in you. Now we're gonna talk about things that occur based on where the needle is. So one is you can get intradiscal flow. So there are at times perhaps reasons you wanna put a needle in a disc, but that's certainly not the intent when you do an epidural. But nonetheless, we know it happens at a rate, maybe 2% or maybe 0.2% depending on who you cite. The astute people in here might chuckle that this has even been reported with an interlaminar injection, which means you went through the dura not once, but twice to get to the disc, which really means the procedurals didn't know what they were doing. But in theory, it's possible. But there are reasons this can occur even if you are doing the procedure correctly. And that can be, for instance, that the disc is herniated into the foramina where you're putting your needle. And that's why you need to review your MRIs before this. It may also just be because there's foraminal stenosis or that the needle drifts it off into the wrong place. So this is a very nice case report from David Levy in pain medicine, where you can see here at the top left of the screen, the needle is in a very good position. It's sub-pedicular, not past six o'clock, definitely above the intervertebral disc space. It's anterior up against the posterior border of the vertebral body. And yet when they put contrast in, it is not spreading along where the needle tip is. It is unequivocally within the disc, right? And then when you look at the MRI, you can see this big black blob here in the top right corner of your screen, and there's some arrows there. So this black blob was the disc herniation that it extended right up to where the needle had been. When you talk about infections, not causing paralysis, so not epidural abscess, just infection in general, the rates are low, but again, I think it's important for everyone to realize that the symptoms that they present with are pain and then fever, and things like CBC and ESR and CRP are later findings. So if you have someone with a pain and fever post-procedure, but their labs are normal, it does not necessarily negate your need to get imaging. Now, I'd also point out this slide is here because it's following the inadvertent intradiscal injection, that the rates of these infections are probably much higher if you inadvertently put the needle in the disc, and that's because you've now potentially introduced bacteria into the disc, which hopefully you all know, or now you do, that it's an avascular structure, right? So there's very little immune cells flowing in and out of there, and it provides a very nice environment for bacteria if you introduce them into there by accident. Another thing that you can cause because of your needle or where it is is a dural puncture, right? So interlaminar injections, it doesn't matter how big the needle is, if you stick it through the dura, you could cause a dural puncture and perhaps cause a dural headache. People debate about the size of needle and what's appropriate, but there is at least one study that shows if you gouge the dura with a 17-gauge needle, there is a high chance you will need a blood patch, and if you poke it with the small needle, there's a much smaller need, right? So you do want to be mindful of what size of needle you're doing even with interlaminar injections. It's unclear how often this occurs with transforaminal injections. It can occur, but it's so rare that we don't really have numbers on it. It's also worth noting that spinal headaches don't always occur with dural punctures, right? They can, but not always. And these headaches will be positional and they differ greatly from steroid-induced headaches, which are much more common. So I almost tell people, look, if you get a mild headache after the procedure and you have some flushing in your face and it's not positional, you don't need a blood patch. This isn't because we put the needle somewhere wrong. This is just a complication from the steroid. Spinal headaches themselves have a much different clinical picture. Earlier in the talk, we talked about these things, so we'll skip over this slide. But again, just to remind you, if you put the needle in the intrathecal space and inject gadolinium, it can die. If you inject lidocaine, they can stop breathing. So that's bad. But again, these are procedure complications related to needle locations, so that falls into this part of the talk again. And hopefully for you guys, this is not, this is simple, right? The take-home point should be, well, just use contrast. But when we give these talks at conferences to people who've been in practice for a long time, we really drive this point home because this is really a game changer because for a long time, when people had contrast allergy, the thought was that you should just use gadolinium. And so this has really been a practice changer within the last few years. This slide also points out nicely that gadolinium just does not appear as well as normal contrast, iodinated-based contrast does on fluoro. So when you're using it, you end up using much larger volumes because it's hard to see, which further increases the risk of neurotoxicity. Again, if you intrathecally inject anesthetic, you can get spinal anesthesia. And if you inject steroids, you can get arachnoiditis. So the last few minutes of the talk, we're gonna talk just about medications now, right? So if you inject lidocaine into the intrathecal space, that'll give you a complication. But there are potential complications even if it's not intrathecal. Now, if you're using 1% or 2% lidocaine, you should not be hitting the toxic doses, right? You'd have to inject 50 cc's to get to 500 milligrams of lidocaine. But there are toxic doses of this and you do need to keep them in mind. We may get within the ballpark of these if you're doing a complicated procedure such as a bilateral radiofrequency ablation where the patient is not sedated and you're just numbing them up lots. But realize there is a maximum dose. What about complications related to the contrast, right? Well, contrast allergies are very well noted. And what to do in these cases is an evolving space because as I mentioned before, the answer is to use gadolinium, but now we can't do that. So do you pre-medicate for their contrast allergy? Do you ignore it, right? Is there a difference between doing a 20 cc bolus of iodinated contrast straight into someone's vein versus injecting one or two cc's of that into a muscle? Are there times now that we're using dexamethasone that the answer is to just not use contrast? And there are guidance documents on this, but there's no clear answers. The other question is renal function. Someone has to have really tenuous renal function for me to get worried about this because if one cc of contrast into their paraspinal muscle or the epidural space is gonna tip them over from being okay to not okay, they were probably going down that path anyways. And then for five minutes now, we'll talk about steroids because this is by far the most dangerous thing we do when we give epidural steroid injections. So number one, it is without a doubt that if you do an epidural steroid injection on someone that has diabetes, there is a very good chance you will increase their blood sugar, that the increase in their blood sugar will likely be around 140 milligrams per deciliter and that that's gonna last for two to three days. That is bore out in many, many papers now. And when you talk to your patients, they will tell you the same thing. The other systemic effect that you get from steroids consistently, so this not rarely that this happens in almost everybody is that you will suppress their hypothalamic pituitary axis. And the potential sequela that has long-term on all the other hormones in your body are variable. So for instance, if you get enough of these, you very well might give someone osteoporosis. You might put them into adrenal failure, but you're probably not gonna change their sex hormone profile, right? So suppressing the HPA axis is universal, but how that affects each individual system is much different. We do know, however, that this lasts for up to three weeks in most patients. And that's probably what should be our guiding light in terms of when we talk about how far apart to space these things. Because if you do an injection and then right when their HPA axis is recovering and you give another injection in two weeks, you've knocked them right back down to where they started. And if you're somewhere where people still do a series of three, which is totally inappropriate, you may have now suppressed their HPA axis for up to two months. The symptomatic things patients will feel, so not the physiologic things, but what patients will feel are more likely just flare of their pain, mild headache, like I referenced before, or flushing in their face. And the flushing in their face really is prominent in perimenopausal women. And really it will get people thinking they're sick and it's very common, up to 28%. So I'm very careful to tell people about this, especially in patients I think that they're likely to get it and you'll fend off a lot of phone calls from people a day or two later calling you and asking why their face is red and why they feel hot. There are some people too you have to worry about, especially people that are kind of fragile bipolar disorder that you might put them into a psychotic episode. That's just a graph of the glucose, which I think we already drove that point home. And now this is a slide of summarizing what I just talked about, which is that adrenal suppression or HPA axis suppression occurs often up to three weeks, but in most people, it almost always occurs for at least a week or two. And while there's limited data on this, I think it is pretty clear at this point that this is both dose response and steroid response. So if you give a high dose of a particulate steroid, you're gonna get into much more trouble than if you use lower doses of non-particulate steroids. This is the last slide I'm gonna talk, so we're ending right on time. And this really could be a talk in and of itself again, but I think it's important to get everyone who's going out and practicing in the next few years to have this on their radar, at least, that there are a number of studies that have all come out within the last year or two, really, and continue to come out every year now, that there is likely a small but real increased risk of infection if you get an epidural steroid injection before a spine fusion. And it's probably not there if it's not an instrumented fusion. So if you're just getting basic laminectomy or discectomy, that risk is probably negligible. And that risk diminishes over time, so an epidural three months before your surgery is not the same as an injection two weeks before. But this really needs to be on our radar, especially as proceduralists, in so much that if I get referred for an epidural on someone who's scheduled for a fusion two or three weeks out, I'd pretty much tell the surgeon that I'm not willing to do it. And hopefully they realize I'm saving their butt, not mine. But this is a rapidly new and evolving area of understanding that will be different even within the next two or three years from now when you guys all graduate. So in summary, when we talk about the risks of spine interventions in general, major complications are major and they're real, but they're super, super rare. But you need to know about them so you can properly mitigate that risk and make it even smaller. Conversely, when we think about minor risks, they happen and they happen to everyone. There's not a single person who does spine procedures, I guess, unless you use general anesthesia, which is grossly inappropriate. But other than that, there's no one that does spine procedures who is not gonna get a vasovagal reaction, who isn't gonna have a diabetic whose blood sugar goes up, who isn't gonna have a patient whose HPA axis is suppressed. And because these things, even though they're not severe, are the common things that you have to deal with and they affect patients, you need to understand these so you know how to manage them. And these are really what should make up the foundation of your understanding. And these are really the things you should spend your time consenting on too, right? Because these are the things that your patients are likely to encounter. So with that, I will say thank you, that I hope not only that the talk was helpful and hopefully interesting, but also that this platform is working for everyone. And I would like to again extend my thanks to both the AAP and to Sterling for having me on and even more thank you to everyone else for spending their Friday afternoon or their lunchtime with me. They hear me blab on. And we do have a few minutes for questions here. So if you have any, I will let Sterling moderate. All right, thank you. We do have some questions. I wanna start by asking, so some of these things are side effects, as you mentioned, some of these things are complications, some of these things are expected effects. How do you communicate these things to your patients and say, hey, this is likely to happen, this may happen, but that's okay. And these other things we don't anticipate happening. Yeah, that's a really good question. So if I have a trainee in the room, my informed consent is probably a little more thorough to be educational, but if I have a patient who I've already talked about these things with in clinic and I'm humming along, so to speak, the way I'll communicate with the patient for a consent, which I think is a very fair consent, especially if you've talked with them in clinic before the procedure is, hey, how's it going? Here's the consent. Few quick highlights. We should mention that there are risk of serious complications. You could even have permanent nerve injury or death, but those things happen so rarely that the chances are one in 10 or one in 20,000, and you probably got through the most dangerous part of the day by driving here. If you have high blood pressure or high blood sugar, there are things that we can almost expect that'll happen. They shouldn't be that severe, but your blood sugar will go up for two or three days by about 100 points. So if your blood sugars are already high, please let me know, because we might need to delay this. And if your blood pressure is poorly controlled, let me know, and we'll make sure we keep an eye on it. Other things that might happen, I don't expect to, but if they do happen or just the nature of the beast and occur at times are things like feeling like you're gonna pass out. So if you feel lightheaded or nauseous during the procedure, please let me know so we can stop the procedure or do what we need to so we keep you from passing out or keep it before your heart rate falls. And then other things like if it's a little bit of pain after the procedure, that's normal, but if it's real bad pain, please let me know. And then we're giving you steroids. So you might feel a little flushed in the face for a day or two, that's normal and nothing to be worried about. You might even get a mild headache for a day or two. And again, that's normal, nothing to be worried about. If we caused a spinal headache, that's a different situation, but we would know that before you left today and we'll tell you about what to expect if that occurred. Thank you. So very conversational, that's helpful. Another question. So when we're talking about increased risk of infection before surgery, what's your timeframe on that? It's okay to do it two weeks, or it's okay to do it two months, it's not okay to do two weeks or a year? What are you looking at? Some studies say three months, some studies say one month. I think it's very clear that it's dependent on whether or not there's instrumentation of the procedure. It's dependent on whether or not there's instrumentation and probably the approach. So even like a ACDF has such a low infection rate, you probably don't need to worry about it. And even more so, when you read the papers, you break it down based on location of surgery and instrumentation, but really what it more likely is, if I had to guess where this is all gonna go within the next few years, is that there is a relative risk of increased infection with all epidurals and all surgeries, and that relative risk is probably less than two, right? You're probably increasing the risk of infection by 10 or 20 or 30%. So if you take a procedure like a posterior cervical fusion that has a known infection rate, let's say of one or 2%, and you double it, then that's gonna be detected in these papers, right? And if you take a procedure where the known infection rate is 0.1, you'll never get a large enough study to capture the increased infection rate where it went from 0.1% to 0.12%. Practically speaking, though, I get worried about procedures that have a higher risk of infection that has to do with the procedure, but also the patient, right, so if they're diabetic, old, have other medical comorbidities. And most importantly, if they are scheduled for surgery, I'm probably not doing the procedure unless that surgery is booked way, way out. So, you know, I think our surgeons who are well-meaning will say, well, we'll get an injection to get this calmed down so you're not suffering while we schedule your surgery, but they fail to realize that these injections, we say take a week or two to start, it's probably more like three or four or seven days, but nonetheless, if I'm doing your procedure and your surgery is booked in 10 days, why the heck am I doing it? So you feel better the day before your surgery. Conversely, if the patient says, well, yeah, if this helps, I'll cancel my surgery, I might do it, I might piss off the surgeon, but doing an injection when a surgery is inevitable, if it's a high-risk patient, that's a clear reason to not do it. Okay, thank you, that's helpful. All right, I think it's about time to close up. Thank you, Dr. Schneider, for joining us. We appreciate it very much. Thank everybody for being here. Again, the daily schedules are updated all the time and they're on that website, physiatry.org slash webinars. Track us down on Twitter if you have any questions or any contributions, and we're looking forward to it. Next week's gonna be a really good week. We have at least two department chairs and more in the works. So thanks for joining us and we will see you next week. Thanks, everybody.

spine procedures

epidural steroid injections

complications

major complications

rare complications

minor complications

informed consent

patient safety

risk communication