So again, thanks everybody for joining us today. We will go through some of the housekeeping things. First, we're going to keep everybody video and audio muted. Sorry, I've been trying to show my face so people know who they're talking to. We're going to keep everybody video and audio muted. If you have any questions, you can find me. My name is Sterling Herring. I'm a PGY3 at Vanderbilt. You can click your participants list and scroll up to the top, double-click my name, and you should be able to send me questions that I will pass on to our presenter. If you have any questions about the lecture series itself, any concerns or suggestions, you can reach out to Candice directly. Her email is there on the screen. I do want to make another point back here. Let's see if I can go backward here. Here we go. At this website, physiatry.org slash webinars, we have a couple of other things that are added. A few weeks ago, I mentioned a wellness activity that was being put on by the AAP resident and fellow committee. That was well attended, and the RFC has decided to do those monthly. It's going to be the first Wednesday of every month via Zoom, and they've got a variety of different wellness activities they're going to be doing. Go to that website, physiatry.org slash webinars, and check out the schedule for the wellness activities that will be coming up the first Wednesday of every month. Without further ado, we're excited to have Dr. Yang back with us from here at Vanderbilt. Thank you for joining us, Dr. Yang. Hey, Sterling. Thanks a lot. Let me see. I'm going to try to share this here. Thanks for having me back. I'm going to share this. Okay. All right, so if anyone has any sound issues, please let me know, or Sterling, just feel free to let me know as well. If everyone can get on this poll here, I would just like to quickly see who our audience is. You can go to PollEB.com slash Aaron Yang 927. Okay, so no relevant financial disclosures. Some of you may know the use of corticosteroids into the epidural space is used off-label, and we'll be talking about that today. I did present this previously at the AAP Medical Student Resident Fellows Workshop. So some of you guys may have been there, may have seen this talk. If you have, then hopefully you'll find this useful to hear again. So what I plan to do is just go over a brief introduction before we talk about the procedures themselves. We'll do a brief thoro-spine anatomy. Then we'll get into the procedures. My goal is to talk about epidurals and facet joint injections, or sorry, facet interventions. I was going to also talk about SI joint complex and how we approach that, but I did give a whole hour talk on that before. So I'm debating whether or not, depending on the time, whether to go over that versus try something else. So we'll see how we're doing on time. Then really the bottom line is that better selection criteria equals better outcomes. That's the main running theme through this. So it looks like we have a pretty even split. We do have more medical students on this than residents, but happy to have anyone listen in. I think that in order to frame what I'm going to go over, there's different levels of what we may expect our trainees to know. And I think it's important for people as they go through training, they may ask, what's important? Should I be knowing this? Should I not? Is this something that I should know as a fellow? And so I'll try to unpack a little bit of that, but not too much. But I think if you're a medical student or a first year resident where you probably have not had much outpatient exposure, I think it'd be good to know what types of injections exist and why we do them. As you get onto some of the outpatient rotations, whether you're a two or three, I think it's important to think about more of who are the appropriate patients we should do injections on and what is the appropriate injection. Because if you choose the appropriate selection criteria, and then you can choose the correct injection that will increase your likelihood of a successful outcome. And this happens by combination of your evaluation and also review of the imaging. Other things that I expect a trainee to pick up during this level of training is to be able to identify landmarks on floral imaging, understanding the rationale of the attendings and their choice of medications, what needles they use, how do they approach the procedure. These are often things I think sometimes trainees may be fearful to ask or just don't even think about asking. But I think as you go through your training, you work with different attendings, you'll find that practice patterns vary. And it's good for the trainee to get an understanding of what the rationale is of why the attending chooses certain things. I think the hands-on part of procedures comes later on. Nowadays, everyone is going to pursue a fellowship if they plan to perform interventional procedures. And I think that it's not as critical to do this so early in your residency training. I know we all talk about numbers. And yes, I think you become more and more comfortable through time. But oftentimes when we just teach people how to just manipulate a needle, I think there's a lot of things that are missed. And oftentimes, we're not better interventionals because of that. And so, you know, by the time you're a four, you should be more comfortable performing certain procedures, obtaining fluoroscopic images without relying on your radtech. I think that's really important, especially as you get out into practice, where if you have a radtech who's not experienced, that can lead to a lot of trouble. And then lastly, at the fellow level, you know, you should be able to perform all these procedures, able to navigate and manage unexpected complications with some assistance. I think complications are inevitable if you do this long enough. It's important to know how to handle that, or at least talk to your attendings, especially in fellowship before you go into practice. This is one of the things I'm sure our residents have been aware of, especially even Sterling. And we always try to have the residents be able to drop the lumbar spine anatomy. The second thing is always check your available imaging before any procedure. Advanced imaging should always be reviewed before any procedure, and it's a good opportunity to go over that and to sort of unpack why the attending chooses that specific injection. What is the rationale? And I think that's something that you can work through as you work and look at the images. I just threw this here on the right side, reading an MRI. This is just something that you can write down. It's a quick check that you can do whenever you come across imaging, whether that's an X-ray or MRI. Obviously, some things you're not going to see on an X-ray. But starting with the ABCs, you know, looking at the alignment, look at the bone, and then the cord, the disc, the exiting nerve roots, the facets, and then G just for gutters, meaning more on the periphery, you know, lateral disc herniations, muscle, et cetera. So this is a prime example of looking at imaging before you do a procedure. This was a patient who I did not do an injection on, but the spine surgeon just shared the images with me. And what you can see here is that at multiple levels, you're seeing cysts, perineural cysts at multiple levels. So if you were planning to do a trans-framework epidural steroid injection on this patient without any imaging, you can imagine the difficulties and the pain the patient will be in because look at where these cysts are. This is another prime example of why imaging is important before a procedure. This was a patient who had spinal surgery who was referred for a potential injection. They repeated imaging before they did the injection, and you can see this large CSF collection right here, not something you want to inject into, further reinforcing that you should review all imaging prior to any injection. I think Nikolai Bogdok has a great resource out there on drawing out the spinal anatomy. I think it's really helpful. You can see here there's multiple steps that lead to drawing this out, but I think it's helpful to visualize and conceptualize where are the structures. Because once you get to the floral suite and you look, it can be very overwhelming of making out the different outlines and different structures. This is the lateral view here. You can see where the facet joints are, and it can be very difficult to identify that on x-ray or fluoroscopy. So again, the more comfortable you get to drawing the anatomy out, the more comfortable you are looking at it real time. On the left here is the fluoroscopic picture of a lateral view of the spine. Here on the right is a cadaver dissection. Really just pointing out, you can see the vertebral body here in purple. You can see the disc space here. And then you have the foramen. And on the right side, you can see the nerve root as it exits higher up in the foramen itself. And then if you superimpose that onto a lumbar spine MRI, this is the nerve root right here and then epidural fat around the nerve root in the foramen. So whenever we're doing fluoroscopic images, again, we're obtaining a PA view, a posterior anterior view. What I'm trying to show in this red box is the outline of the vertebral body of L4, and we're squaring that off there. L5 is not squared off because you cannot see the end plates, the superior inferior end plates. You guys will probably hear this a lot whenever you're in the fluoro suite about the scotty dog. And this is one of those things I always try to recommend trainees to look at on a spinal model first, because it can be really hard to identify some of the structures whenever you do that as the first step. But what you're seeing here is an oblique view towards the right on the image here. And then you have the structures of the scotty dog. You have the ear up here, the head and the nose and the leg. And so that correlates to the superior articular process up here, the pedicle, which is the eye of the scotty dog, the transverse process as the nose, lamina, and the inferior articular process here in the front leg. Again, this is something that is helpful to go over on a spinal model. It'll be asked, and the reason why it's often asked for trainees is because this is how we often approach a lot of different injections, whether you're doing a medial branch block, you're doing radiofrequency ablation, transforaminal epidural steel injection, or facet joint injection. So I want you to take a minute and take a look at this x-ray. Obviously this isn't as interactive as we would like it, but just run through your ABCs here, and I can tell you the history of this patient. So this was a patient that came to me, was a maybe, I think it was 20-year-old collegiate lacrosse player had axial low back pain, predominantly on the left side. They had tried multiple rounds of physical therapy, chiropractic care, deep tissue massage, TENS unit, nothing really gave her relief. She did not have any radicular pain. Most of the pain was localized to the left low back. So again, if you go through the ABCs, you can look at alignment here, and alignment looks pretty good. Look at the bones, and I would say the bones, for the most part, there's nothing remarkable from there. Another important thing to count, another important thing is to count the vertebral body. As you can see here, we have 1, 2, 3, 4, 5, and possibly a 6th lumbar vertebrae. So again, it's important to count. It's often hard to identify that on the lateral view, but if you look here, there's 1, 2, 3, 4, 5, and then 6, it's much more clear there at the lower part right before the sacrum. So what this patient has is something called Bertolotti syndrome, and some of you probably have already heard about this before, but this is when they have a transitional vertebrae. And it often doesn't become symptomatic until the 20s and 30s, like my patient, and it can affect about 4 to 8% of the population. So it's always important to count the vertebrae, and it's much easier to identify that on x-ray than MRI. And it can cause secondary pain in the iliopsoas muscles, asymmetric facet arthropathy. And so we did, since this patient failed extensive conservative treatments, we decided to try an injection into that articulation. And you can see here on the fluoroscopic image, we have the lowest transitional vertebrae right here, but you can really see the articulation here on the left side when you're looking under fluoro and oblique the C-arm. And so this is a marker that's pointing to that joint. And so we did an intra-articular joint injection into that area, and she did remarkably well, returned back to lacrosse, actually had relief pretty immediately that day. And so this is not often a surgical treatment, really treating symptomatically. Again, this was a collegiate lacrosse player who had no plans to continue professionally or further after she graduated, so we're really just trying to get her through the season. And so she's done really well. Just another reminder to review your imaging, have a systematic way of going through the imaging because that's really important. So this is a type in your answer poll. And so for those who are here live, what do you think are the different types of epidural steroid injections? You can type that in or text it. Give you a second here to think about that. So transforaminal, yep, interlaminar, caudal, great. So yep, so we've definitely, we've gotten all the ones that I was thinking about. So there's predominantly three ways that we do epidural steroid injections. There's the caudal route, the interlaminar route, and the transforaminal route. And so what is the main differences? So the transforaminal route directly targets the spinal nerve in the nerve foramen. Studies have shown that it can lead to more ventral spread of the medication. We'll talk a little bit about why that's important. Interlaminar injections as it states is between the lamina and the interlaminar space. It has been around much longer and has been done blind for many years. So you may find some of the older practicing attendings who used to do interlaminars without any fluoroscopic guidance and they're really going for what we call the loss of resistance as they get through the ligamentum flavum. And this is not really targeting a specific nerve route. It's really putting the medication at a certain spine level. But the medication can spread to different areas. You can modify how you do the interlaminar approach where you can get more ventral spread to a nerve route. And the last approach which has been around maybe even longer is a caudal epidural steroid injection that you're doing through the sacral hiatus. Most of the medication does not go ventral, it's posterior. And it often does not spread higher than L4-5. Very rarely will it get up to L3-4. I call the caudal epidural steroid injection, as you can see here, going through the sacral hiatus, this is really more of a shotgun blast approach. The interlaminar injection, again, you can see here and right here is going between the lamina and you're putting the medication posteriorly here. Transforaminal route is going near the nerve root foramen. I think it's important to first step back and say why are we even injecting steroids? Well, it's to inhibit an inflammatory cascade, prevent transmission of nose receptor C-fibers. A common thing I think is a misconception among many people is that we're trying to treat a quote-unquote pinched nerve and I've been guilty of doing this and it's often easy to explain to patients, hey you have a pinched nerve. But really what we're treating when we're doing these epidural steroid injections is treating more inflammatory process than a pinched nerve because we know that pure mechanical compression of the spinal nerves does not necessarily produce pain and the degree of nerve root compression does not correlate to pain severity. And so if you have looked at multiple MRIs where you see multiple areas where there's foraminal stenosis, you can conclude that maybe the nerve is being pinched there. We all know that MRIs show findings in asymptomatic people. So just seeing that does not mean necessarily it's symptomatic. So that's not, you know, to be really appropriate with patients, we don't say we're treating a pinched nerve, we're really treating an inflammatory process. This is a prime example, a patient here with L4-5 foraminal stenosis and you can say, well how do I know that? And you can see white here, we talked about epidural fat around the nerve root and you don't see as much of that here in the nerve root foramen. So this may be explained to some patients as a pinched nerve here at L4-5, but truly this could be seen in asymptomatic patients as well. So who should get an epidural steroid injection? So we know that for epidurals, you know, we predominantly use it for patients who have radicular leg pain. And so in this case, this would be patients with a disc herniation, spinal stenosis, the question is still out there about how much epidurals can truly help for spinal stenosis, but predominantly used for more radicular type symptoms. We obviously stay away from patients who have more axial pain, such as facet mediated pain, and obviously not in the SI joint and hip pain. And lastly, peripheral nerve entrapments where patients would not benefit from an epidural steroid injection. So as I mentioned, it's used for radicular pain. There's evidence out there that it can help about 60% of patients get at least 50% relief for about one to two months. And so we know that epidurals can help more for radicular pain in the short term. It's not a long-term solution. We combine epidurals with a natural history of how patients recover after radicular pain, and we can hopefully expedite the relief that they get as opposed to just relying on time. We know that it can be effective more in patients with contained disc herniations or low grade compressions. It works better for patients who have more acute symptom duration rather than chronic, effective than placebo, and then reduce the burden of disease by improving function and avoiding surgery. And we've got lots of different studies out there that support epidurals for radicular pain. And so in terms of how do we choose a procedure on who, we really rely also on how does an image help plan a procedure. And better targeting, we know, can lead to better outcomes. And so advanced imaging, like an MRI, is very important to have before you plan a procedure and should always be reviewed again right before you go in there with the patient. And so the point of any procedure is to get the medication to the target. And sometimes trainees say, okay, so where is the target? And the target, if you really try to put into words, is the interface of the neural tissue and the compressive lesion and flow to the preganglionic nerve in the ventral epidural space. That's a lot of words right there. What does that mean? So in this example, if you have a disc herniation here, right, here's the neural tissue and the compressive lesion right where the arrow is. And you want the medication to flow in that area preganglionic and in the ventral epidural space. So not back in here, but right here where the arrow is, where the ventral epidural space is located. And we know that medications that have been shown to be placed in the ventral aspect have improved outcomes in terms of patient-reported outcomes. We know that there may be better outcomes that support transferaminals because we mentioned that it can reach the ventral epidural space as compared to interlaminers. And then there's greater efficacy when contrast or medication reaches that preganglionic area. So this is a prime example. So if you have a patient that comes in and has a disc herniation at L3 and L4, and they have L4 radicular pain, and say you have a referral from a spine surgeon that says, inject into the L3-4 space, we have to realize that there's more than one way to do a transferaminal epidural steroid injection. So in red, you could do a supra-neural L3-4 epidural transferaminal epidural steroid injection. You could do a retro-neural L3-4 transferaminal epidural steroid injection. You could do a infra-neural L3-4 transferaminal epidural steroid injection. And then you could do a supra-neural L4-5 transferaminal epidural steroid injection. And again, the target is the L4 nerve root. I think it's important for trainees to understand that there's more than one way to do a transferaminal epidural steroid injection. And you can see here by this example, some of these injections, obviously they're in different locations. So take a look at this. And the question I want to ask you on the next poll is, which of these injections would get the medication close to your target? And this is the target nerve right here, the traversing L4 nerve root. So here's your chance. So far, we have one for supra-neural L3-4. All right, so super neural L3-4 seems so far to be the most popular answer. Okay, so I'm glad I went over this because it is a little mixed bag here. So I would argue in looking at this that the bottom two approaches may get the medication closer to the target nerve root. And I think the poll reflects what I would say majority of people would say. So if a spine surgeon referred a patient to you and said, hey, this person has L3-4 disc, I think an L3-4 injection would be the best. And the only thing we were ever taught through residency and fellowship training was a super neural approach. We would be doing a L3-4 super neural epidural steroid injection. What potentially this may do is cause most of the medications to flow cephalad, not caudal, where the nerve root is. And so hence the reason I would argue to put the medication either infraneurally at that foramen or supra-neurally at the foramen below to get the medication close to that nerve root. And so this really brings up the two different types of transforaminal epidural steroids that exist with the super neural approach or the safe triangle approach being by far and away the most common transforaminal epidural steroid injection we are taught. And so this picture was taken from Furman and you can see the needle coming here under the six o'clock position and what you're going to see is dominant cephalad flow. There's a higher risk of vascular uptake when you do a super neural approach. The infraneural approach, also known as Kamben's triangle, which I'll show on the next picture, can go infraneurally, but also you can see a super neural flow if you're higher than L5. So again, just another schematic. The traditional safe triangle super neural approach, here's the exiting nerve root here on the right side, the same thing, and your needle tip is going here underneath the six o'clock position here. You don't want to go past that because obviously dura is there. You can see there's a greater arterial supply here, hence leading to more vascular uptake. The other approach, the infraneural, is also known as the Kamben's as the Kamben's triangle, and the triangle is bordered by the exiting nerve roots, the superior articular process, and then the superior end plate below. So again here, this is the super neural approach. Makes sense, you're above the nerve right underneath the pedicle. If you look at contrast flow patterns, which you may have seen, you know, in the fluoro suite if you've been there already, you can see the contrast flowing superiorly, right. This is by far and away, again, the most common epidural steroid injection you will see whenever you're in the fluoro suite. Infraneural approach is obviously targeting below the nerve root. Higher risk of disc puncture, as you can see here, the proximity of where that needle tip is and the disc. I would argue that you probably don't want the disc to be this far anterior because you can, that's a high risk of disc puncture. And you can see here the flow looks different. If you're above L5, you can see cephalad flow, but you can see a lot of these injections are at L5-S1 foramen. You can see it flowing inferiorly or caudally. So really my main point with epidurals is that radicular pain is inflammatory. Epidurals are effective in treating radicular pain, not axial pain. There's some evidence that supports that transforamals may be better than interlaminar approach, again, reaching more ventral flow to that target point where the neural tissue is compressed by the disc. The other thing I'd really go over is that dexamethasone appears as effective as particulate steroids. For those who don't know, you know, we have different medications that we can choose. Dexamethasone is a non-particulate steroid and the way we know that is just by taking a look at the steroids itself, it's clear. But if you compare it to a particulate steroid like Kenalog, you can see it's chalky white. There's large particles, potentially cause an embolic event and spinal cord injury. And so medications like Kenalog or Triamcinolone, which were used in the epidural space, are no longer being recommended. Even though you may still see in the community some people using this, would not be recommended. In fact, there is a black box warning on Triamcinolone for use in the epidural space. And then lastly, better targeting equals better outcomes. And as we saw, based on the different approaches to epidurals, that not all epidurals are the same. All right, so before we move on to the next topic of medial branch blocks, I want to hear some hobbies that people have picked up in the past few months. You got to reset the brain here. Zoom, that's a good one. Definitely pick, I don't know if you want to call it a hobby. Oh, congrats, fatherhood to somebody. That's great. Cycling, running. Nice. Yoga. Nice. Yoga. Internal medicine. Great. These are all important things. Part of the reason I wanted to think about this is because, as you know, yes, you know, we're busy with work, but there's more to life than just work. And it's important to have hobbies, outlets, friends, especially through this crazy time. So the next topic I'm going to talk about is facet-mediated pain. And so we know that the prevalence of facet-mediated pain is about 15 to 40 percent, much higher in older patients with chronic low back pain than those who are younger than 40. A majority of facet-mediated pain occurs at the last two lumbar segments between L4-5 and L5-S1. And really there's been no consistent imaging findings in those who are proven to have a facet-mediated pain. So what do we have in terms of available procedures? So we have diagnostic procedures, we have therapeutic procedures, radiofrequency ablation, intrarticular steroid injections, and then medial branch blocks for diagnosis. So when you're thinking about someone with facet-mediated pain, you're going to have increased likelihood for someone who's advanced in age, has mostly axial pain, predominantly in the lower portion of their lumbar spine. Those who have decreased likelihood are going to be those who are younger. They may have pain more with flexion. They may have pain that radiates all the way down to their foot. Someone like Justin Bieber may not have facet-mediated pain, although his lifestyle may warrant that he might. But if you're thinking about injections as a diagnostic test, I mentioned before there's not been a really great physical exam or history finding that's proven to be reliable in diagnosing those with facet-mediated pain. So almost like that side joint like we talked about, that leaves injections as the gold standard for diagnosing facet-mediated pain. And really the evidence shows that medial branch blocks have the strongest evidence for diagnosing facet-mediated pain over intraarticular injections, whether that's with steroid or anesthetic. So I really would not recommend intraarticular facet joint injections to be done to diagnose facet-mediated pain, but more medial branch blocks. And what are we doing with medial branch blocks? So what we're doing is we're anesthetizing the medial branches which innervate the facet joint. And as you can see here in these pictures, the target is between the supraarticular process and the transverse process. So I'm sure your attendings love to ask this question to you guys, but we'll try this one here. What nerves innervate the L5 and S1 facet joint? More practice the better. All right, so I'm going to lock this here. I would say you guys are correct. It would be the L4-5 medial branch and the L5 dorsal ramus. This one's a trick question, and I'll show you, excuse me, on the next slide, the innervation breakdown. But L4-5 medial branch is a very common answer, but we're actually anesthetizing is the dorsal ramus and not necessarily the medial branch. L5-S1 medial branches would be incorrect. The S1, S2, S3 sacroilateral branches, as we talked about, provide innervation to the posterior sacroiliac joint complex. L3-4 medial branches would innervate the L4-L5 facet joint, which no one answered that. Other things, I think that was pretty much on that one. So here's a drawing here. So each lumbar facet joint is innervated by two segmental medial branches. And in the cervical spine, it's intuitive. There's really no memorization or thought process. If someone says what medial branches innervate the C5-6 facet joint, it's C5-6 medial branches. So it's really easy for that standpoint, but the lumbar spine is a little bit more confusing. So if you look at the L2 and L3 facet joint right here, you see contributions from the L1 medial branch as it innervates right here, and then also the L2 medial branch as it innervates here. So L1 and L2 medial branches would innervate the L2-3 facet joint. This was taken from a Furman book again. If you look at L3-4 facet joint, you would be anesthetizing the L2 and L3 medial branches. And then when you're coming down to L5-S1, it's going to be the L4 medial branch. And really, the L5 dorsal ramus is what your target point is. There is a medial branch right here, but that's not where we're anesthetizing. That's not what innervates the L5 and S1 facet joint. So this one's a little tricky, but really the only exception when it comes to the lumbar spine. So these are just a couple of pictures, again, targeting the medial branches here as it courses along the junction of the suprarticular process, transverse process. Here's a contrast cytoconfirmed placement. And here is just a drawing of where the nerve lies here, and that's the target. So we talked about this with the SI joint, but a treatment that you can offer to someone who has facet-mediated pain after diagnostic medial branch arthritis is something called radiofrequency ablation. What you're using is electrical energy to cause a thermal lesion to coagulate the nerves and hence anesthetize that painful structure. A couple of things with this picture here. You can see in the top right, there's different needle gauges that you can use. And what we see is that different needle gauges can provide different lesion widths and size. And so it can make a difference whether you use a 22-gauge needle or a 16-gauge needle. The other thing to point out is that how you actually do the ablation can make a difference. And so this is something called the perpendicular approach, where you are bringing your radiofrequency needles and bringing it perpendicular to how the medial branch courses. So here's the medial branch as it goes over like this. You can see if you place your probe like this, you're only getting a small lesion size right here at the tip of the needle. The other approach is called the parallel approach, where you're coming in from a very steep caudal angle and placing the radiofrequency probe along the course of the medial branch. So if you look at this picture here, this is a PA view. You can see the probes for a perpendicular approach comes right here. The parallel approach comes, again, from an inferior angle. You're working your way up, so you're parallel with the medial branch. So why does that matter? Well, first, I think, let me just go back a slide. You may not even know that there's a difference. And next time you're in the floral suite with an attending, you may look at it and say, okay, this is what it looks like. Well, there is a difference in how different people are trained in doing a radiofrequency ablation, whether they're doing a perpendicular or parallel approach. And so this was a great study, an article published recently by Dr. Schneider in our department. So you can see the reference down here. But what we see is that selection criteria really matters. And we talked about this with the SI joint, but what is your threshold of percentage relief for blocks? Because that can also lead to who you're choosing to do these procedures on, and the potential chance of how much relief they're gonna get. So if you see here, if you do one or two blocks, and your threshold for cutoff for diagnosing someone with facet medial pain is 50%, and then you do a perpendicular approach, there's probably a 50% chance of achieving 50% relief. What the authors concluded, if you just did one block in a perpendicular placement, you may have inferior outcomes that may not be greater than sham. It's not great. If you do two blocks, and you use the cutoff at 70 to 80% relief, and you perform a parallel approach to the radiofrequency ablation, there is a 50% chance of achieving 50% relief, but there's a 25% chance of achieving 100% relief. And that changes if you use 100% relief as a threshold, if you do parallel radiofrequency ablation lesions, there is a 56% chance of achieving 100% relief. So what are we trying to take away from this slide? Well, first, the cutoff in terms of percentage relief you use can make a difference in outcomes, because you're gonna be potentially getting false positives and performing ablations on people who don't have facet medial pain. And then also that there is a difference in outcomes, whether you do a parallel or perpendicular approach. So, as I mentioned in the beginning, exam and imaging have limited diagnostic validity in diagnosing people with facet medial pain. Really the gold standard that we have are medial branch blocks, using two blocks and small volume injecting, because there's a high false positive rate if someone gets only one block, about 40%. So that's really high. So that's why we always advocate to do two controlled blocks, because this will also predict response to ablation as we saw in the prior slide. We typically don't recommend facet joint injections as a diagnostic tool for medial branch blocks. And there is a difference between those who get a parallel perpendicular placement of the needle. And I mentioned also briefly about the needle gauges, they can make a difference, whether you use a 22 gauge needle or 20 gauge needle, typically we recommend people to use an 18 or 16 gauge needle for radiofrequency ablation. So, next question. Since I have you guys on here and we're utilizing Zoom much more, I'm curious for myself, what comes to mind when you think of a good Zoom lecture? I'm being selfish here, I wanna know how I can be a better Zoom lecturer. Hashtag virtual didactics, okay. All right, Sterling, you don't gotta put my name on this. Hey, I plugged the virtual didactics, but the Yang thing wasn't me. All right, backgrounds, concise, okay. Cool. All right. Wow. All right, images and videos. Justin Bieber, all right. I don't think we'll be getting Justin Bieber on this calling time soon, unless Sterling can pull some strings here. All right, so I was trying to see how much time we had left because I was gonna go over the SI joint stuff, but we already did that last time. And considering a didactic lecture, I really wanted to try to make this also worthwhile for you guys. So, when I was thinking about this, I was thinking about, so, when I was thinking about this, I made this up today, and I think I'd rather do this than go over the SI joint stuff. If you're interested, like Sterling mentioned, you can look that up, you can watch that video. But I'd rather go over the inflammatory cascade. And I know our residents have already heard this from me, but I think it'd be go over with you guys. So I want everyone on this call to grab a piece of paper and pencil or pen, and then walk through this with me here. So I'll give you a moment, grab a piece of paper, grab a pencil or pen, and we're gonna walk through this. So hopefully you have it now. So in the top corner, we're gonna put some type of injury that will lead to the inflammatory cascade. So whether that's a disc, nerve, tissue injury, okay? Then I want you guys to just think for this as we go through this in your head, answer this in your head, dust off the cobwebs. So what happens is activates phospholipase A2. Subsequent leads to production of arachidonic acid. So we're gonna write this out on your piece of paper. So once you have it down, you're gonna memorize this forever. And so we know that arachidonic acid produces thromboxane and prostacyclin. And it's aided by this by the COX enzymes, COX-1 and COX-2. COX-1 primarily producing thromboxanes, and they're predominantly located on platelets. And COX-2 is predominantly on endothelial cells. So what happens next? So thromboxanes are typically responsible for vasoconstriction, platelet aggregation, and the mucosal lining in the GI tract. Prostacyclins predominantly cause vasodilation and decreased platelet aggregation. So this is important to know because if you have a injury, we talk about trying to target COX-2 because the reason why you have increased production of COX-2 in an injury is because you're getting increased perfusion to the kidneys and the tissues that are damaged. So hopefully everyone has time to write this down so far. Now we're gonna talk about the different things we can do or prescribe to treat some of the aspects of this cascade. So I want you to ask yourself, what would decrease production of arachidonic acid? What would that be? Think about this in your head. I'll give you a couple seconds before I put the answer up there. It's gonna be steroids. We talked about with epidural steroid injections, we're talking to phospholipase. What we're doing is reducing production of arachidonic acid. I threw this here on a side, although we're not really typically prescribing patients aspirin, but aspirin has affinity for COX-1. And so if you give someone a non-selective anti-inflammatory and someone's taking aspirin for cardio protection or stroke prophylaxis, there's going to be potentially decreased binding of aspirin because you have a non-selective COX inhibitor on board. So just something to think about. We also worry about bleeding risk on aspirin. It makes sense, right? With platelet aggregation. Why do we give it for prophylaxis for many different things? Because we want to prevent vasoconstriction. The next medication is Celebrex or Celecoxib, which is a predominantly COX-2 inhibitor. Binds COX-2 about nine times greater than COX-1. And so you guys probably remember hearing about the medication Vioxx, which was taken off the market. And what they saw was that there were lots of cardiac events occurring on patients with Vioxx in a study. What happens is if you block COX-2, what's going to happen? You're going to lose vasodilation of those cardiac vessels and cause increased vasoconstriction. And so more cardiac events were seen with Vioxx and it was taken off the market. Was not seen with Celebrex, and hence why we can still prescribe that medication. And also being really the only COX-2 inhibitor out there that we can prescribe. Then we have the non-selective COX inhibitors, which I'm trying to portray with this X. And those are medications like naproxen, ibuprofen, ketorolac, endomethicin. In fact, meloxicam at high doses, which 15 milligrams is the highest dose, gears is more, tends to be more non-selective. Then you have COX-2 preferential. Although it's not a true COX-2 inhibitor, you're sort of in this in-between. We have etotilac or lodine, diclofenac, and meloxicam at low doses tends to be more COX-2 preferential. So hopefully this helps out. I mean, we always, sometimes we just start prescribing medications after a while and we forget, but it's just a good schematic to understand why you may see certain side effects. And I put this article out there. I think this was a great review for you to look at. It breaks it down into easy to digest information. It talks about what medications you would tend to consider if someone has cardiovascular disease, kidney disease. So I thought it was a nice, concise way of breaking down the information. And especially if you're going to prescribe anti-inflammatories in your practice, I think is good to just go over this once in a while. All right, so we're going to move on and finish up here. Hopefully this was helpful. So we went over this last time. I'm just going to breeze through this real fast. A few myths. It's easy to inject into the SI joint. The medicine stays in there. Sterile injection into the joint treats the pain coming from there. We talked about fluoroscopy. Fluoroscopy is not perfect, but there's still about possibly as high as 20% miss rate. We talked about blind injections, how poorly accurate blind SI joint injections are. In fact, I very rarely hear it being done anymore. There's different modalities that you can use to do SI joint injections. To be honest, I would recommend fluoroscopic guidance if you had the option. We really, the main barriers to ultrasound obviously is the lack of vascularity that you can see with the injection under ultrasound. We talked last time about the dual innervation of the SI joint. So the orange portion being the posterior ligamentous aspect, posterior portion of the joint, which is innervated by the sacral lateral branches and fibers of the L5 dorsal ramus. Then you have the articular portion of the joint, which has innervations from the lumbosacral trunks, the obturator and gluteal nerves. It's important because what we do in terms of treatment can affect possibly one of those structures and not both. And so intraarticular injections, trying to really focus on the joint itself as the pain structure, but you can also have pain that arises from extraarticular structures, such as some of these ligaments. Dr. Prather did a great job of going over this. And then we talk about radiofrequency ablation of the SI joints. And what you're really addressing by doing the radiofrequency ablation is only the posterior portion of the SI joint complex and not the articular portion of the joint. That's really the main take-home point that we're trying to drive across. A lot of the studies in the past have used intraarticular joint injections to diagnose patients with SI joint pain. And we see that the positive response varies all over the place. And there's really a high false positive rate. And part of that is that the assumption has always been that pain from the SI joint is all intraarticular and there really were no extraarticular sources of pain, which obviously now we have found that there certainly are extraarticular causes of pain around the SI joint. In terms of the technical limitations, you can get leakage of the medication. There could be medication that goes into the foramen. The medication can spill out of the joint and onto the posterior complex area, even anesthetizing the posterior ligamentous structures. And then lastly, obviously we talked about the difficulty of being sure that we're actually in the joint itself. There's different ways to diagnose patients with posterior SI joint complex pain and determine who may move forward with a radiofrequency ablation. Oftentimes now we're doing what's called the sacral lateral branch blocks. We're anesthetizing the sacral lateral branches. Not going to delve into this, but ultimately studies have shown that you should do multi-site multi-depth blocks, not single site single depth blocks. And it's important because when you look at the evidence for radiofrequency ablation of the SI joints, the success rates are completely variable. It's all over the place. And part of that is because they used intraarticular joint injections to determine who would get a radiofrequency ablation. So key points, a lot of this I went over last time, but history, physical exam imaging all have limitations in diagnosing SI joint pain. Not all pain is from the SI joint itself. Think about the extraarticular parts. Intraarticular SI joint injections do not accurately predict response to ablation. Hence, we should be doing sacral lateral branch blocks, not intraarticular joint injections, if you're trying to determine who's going to benefit from an ablation. So here are my parting thoughts. Needle driving skills can be taught to anyone at any time. That really does not make you a good interventionist just because you've done thousands of injections. And that's why I think it's important to step back when you're first learning this to have a solid foundation. Ask your attendings questions. Ask why they choose the medicines and needles they do. Because I think that can separate you from those who just are taught to just drive a needle to a point. And if they're not told where to put that needle, then they're just going to do the same thing over and over again where they think is the right spot. Epidurals can help radicular pain. They're not all created equally. Lumbar medial branch blocks are the gold standard for diagnosing facet-mediated pain and can predict response to ablation. And pain can arise from different areas in the SI joint. So a lot of these people on here have helped me by sharing their slides, sharing the information, so I wanted to give thanks to them. And that is it. Got three minutes to spare. Thank you. Barely made it, barely made it. No we have a couple of questions. One is facet-mediated pain in young people, what are your thoughts on MVBs or RFs with regard to multifidus muscle atrophy? Is that something that can cause weakness over time? I know that's an ongoing debate. Any thoughts on that? Yeah there's been a few studies that looked at cross-sectional multifidus size on MRIs post-radiofrequency ablation. I don't think it showed significance in terms of changes in the multifidus muscle itself. A couple thoughts. One, if they're really young we have to really first question is it truly facet-mediated pain? Two, personally I try to avoid radiofrequency ablations on the very younger, I mean maybe 20s to 30s population just because I don't always suspect they have facet-mediated pain. The other thing you have to realize is multifidi innervation is segmental. There's more than one medial branch or sorry yeah one medial branch that innervates the multifidus muscle. So I don't think by creating a radiofrequency lesion at one or two levels is going to cause a complete atrophy of the multifidus. With that being said, I'm not really doing these frequently in the younger population. Again just being the fact that what is the prevalence of facet-mediated pain in those who are younger than 40 is not very high. So yeah hopefully that was. Yes definitely. If you get something a youngish person and you're saying maybe this is facet mediated are you going to think twice about doing an MBB or RF? Are you going to think about maybe a facet and a joint injection, intra-articular injection? That's a great question. You know if I'm really thinking that they may still have facet-mediated pain, not saying that they may never have it, I probably would choose the procedure that would be the most diagnostic which would be a medial branch block. And then after you do a medial branch block to confirm that they do have facet-mediated pain then the decision could be said about do I do a radio frequency ablation or do I do a intra-articular steroid injection. Again the evidence for intra-articular steroid injections is very minimal in terms of how it can really help a patient in terms of outcomes, but again sometimes you're very limited in what you can offer a patient. Fair enough. Okay can you clarify first line inset choice if the patient's on aspirin for secondary prophylaxis? We go with Celebrex or what? Yeah that's a great question. I probably would choose a meloxicam being more COX-2 selective than COX-1. You know there is still some concern about Celebrex and cardiovascular events so it really would depend on what they're on aspirin for. If it's for cardioprotective effects or they have cardiac disease I would be a little hesitant to prescribe Celebrex. I probably would think more of a COX-2 preferential like meloxicam at a low dose. Okay. I will say that going off of that if you read that article the medication that has been shown to have the least cardiovascular events is naproxen. Okay and obviously Tylenol is a winner too right? Yeah Tylenol obviously not being a part of this cascade but yeah. Okay thank you. Spinal manipulation, osteopathic manipulative medicine or I'm blanking on the what do you call those people that pop your back? Yeah chiropractor care. What about it? Just my thoughts? Yeah is that something that can augment interventional care? Is that something to avoid? Is it something that you know maybe is appropriate but not at the same time? I get this question a lot and if you look at some of the guidelines that I put out I think you know spinal manipulation there's some decent evidence for that more in the acute phase. I think the trickier thing is when patients have chronic axial pain for example and the patients come in and say should I be continuing this? You know look I'm not gonna it's there's a lot worse things that they could be doing than spinal manipulation but you know I just have them think about hey okay as long as you know you know if you're going to this three times a week and you're paying out of pocket what is the financial implications of this right? Just having them think about it you know I'm talking about the lumbar spine in particular. I'm not that for me personally I'm not the type that's going to say don't ever do it. I don't want to ever see if you're doing this kind of no. I think that you know in the grand scheme of things if it's helping them and giving them long-term relief then I'm all for it but I think there's definitely what I try to think about is how is this affecting them financially? Are they going every two you know are they going two three times a week and they only find short term relief? I would ask them when do you plan to stop or is there a stopping point? I think that's a great point. I would add to that that I think there's some data for short-term relief of low back pain with manipulation but I've been in a clinic with you and you said what would you say if I said yeah I can take care of your pain come back to me three times a week for the rest of your life and we'll take care of it. Obviously they would not respond well to that. Great. One more question. Thoughts on SI joint fusion procedures like corner lock and SI bone? Oh boy. Short answer I'm not convinced. I mean like I said we already have enough trouble diagnosing patients who would benefit from radiofrequency ablation. I've not delved into the literature enough but I would really be curious how they're determining who gets the corner lock. You know there's been literature out there that the SI joint itself does not move significantly and you know those ligaments that I talked about ossify as you get older. So the question is by creating more of a tension there that is that really the problem? Is the problem because it's moving too much and I'm just not convinced and like I said I think this is honestly going to be a phase. It's not going to last very long but you know that's part of the thing we face in pain medicine. Something comes out and we're all on board and then we find out it's not really helping a lot of people. So that's just my two cents on that. Perfect. Sounds great. We're already over time a little bit. Thank you very much Dr. Yang. We appreciate you joining us. Fantastic as always. If anybody wants to reach out to Dr. Yang directly you can find him on Twitter AaronYangMD. Please feel free to reach out to him. He's a very welcoming guy. He won't hate you too much. And then you can reach out to me or Candice at AAP on Twitter as well. And one more plug for the AAP RFC wellness events. All of that information is on that webpage there physiatry.org. Please feel free to check them out on the first Wednesday of every month and thank you everybody for joining us today. Thank you Dr. Yang. Thanks for having me.

pain management procedures

epidural steroid injections

radicular pain

advanced imaging

corticosteroids

facet-mediated pain

medial branch blocks

radiofrequency ablation

sacroiliac joint (SI) complex

questions in pain management