Okay. Good afternoon, everybody. Thanks so much to the Academy for hosting us and for the planning committee. I'm Dr. Kirshner, and this is session 1501, Navigating and Troubleshooting Fluoroscopic Procedures, Tips and Tricks from Optimizing Anatomy to Needle Driving. As far as my disclosures, I received royalties for some of the books I've helped to work on, including the Atlas of Image-Guided Interventional Spine Procedures, of which I'll be using some images for this talk, and special acknowledgment to Dr. Fuhrman, one of my mentors, who sort of devised this algorithmic approach that we'll be discussing today. I'd like to introduce my co-speakers and collaborators. Really happy to have Dr. Wu with us. He's an Assistant Professor of Spine and Musculoskeletal Medicine and the Associate Residency Program Director in the Department of PM&R at Rutgers New Jersey Medical School, and Dr. Andrew Creighton, who's an Assistant Attending Physiatrist working with me at the Hospital for Special Surgery and an Assistant Professor of Clinical Rehabilitation Medicine at Weill Cornell Medicine. So the goal of our procedure is to review the algorithmic approach to doing spinal procedures, discuss bevel control, and review other helpful hints. Basically, when you want to do a spinal procedure, I think about it as trying to go to a friend's house. You need to know the address, you need to have a map of where you're going, and then you need to know how to operate a vehicle to get there. So similarly, we need to know what views are going to help us get to the position we want to be in, what are our safety views to make sure we're doing it safely and effectively, and then we need to know how to drive the needle similar to driving a car. So this algorithm I sort of find helpful. And regardless of how difficult the procedure is, if you follow these steps, most procedures fall into these steps. So initially, we want to start with a trajectory view, which is our coaxial or hemoglobin view, and that's to see that we have an unobstructed path of the needle to our target. But then that's not necessarily safe. So we want to get multi-planar imaging to ensure that we can see the needle in multiple planes, because one view is no view. There's always a safety view, and sometimes that may be our trajectory view or one of the other multi-planar views, but that may be an additional or different view. And then finally, there are specific views that we want to use contrast in to identify that the medicine is spreading where we want to go safely and effectively. And then we want to avoid that red stop sign. So those are our suboptimal views. So sometimes these views overlap and sometimes they're different. When it comes to doing spinal procedures, we want to take into account the patient's anatomy. We want to review any relevant imaging ahead of time. And for a lot of these procedures, we're going to have to adjust the CR based on the region of the spine we're working in or the natural lordosis of the patient. So remember to use your CR to your advantage, tilting, wigwacking, obliquing, et cetera. So these are just some of the positions that will place the CR. And for some of you, this may be review, but I want to make sure we're talking the same language and are consistent. So we can see here, this is our x-ray beam. And then the image intensifier is what's going to receive the x-ray and then produce the image. So this is cephalad tilt, and we describe the tilt relative to the position of the image intensifier. So cephalad tilt, the image intensifier is leaning towards the head of the patient. With caudal tilt, the image intensifier is towards the feet of the patient. And then with the obliquity, you can see the CR is about 30 degrees oblique. Now, if the CR is 90 degrees oblique and the patient is prone, this is a lateral, but you can imagine if the patient's sidelined, this would be an AP view. So when it comes to doing these procedures, we want to start with a trajectory view, and this is our hubogram or coaxial view. This helps us sort of get a lay of the land, identify any agronomic anatomy, any structures that may be obstructing our path. So this is an example of a ganglion impar block, and we're going to use this to sort of go through the typical imaging. So our trajectory view is going to place the needle at that sacrococcygeal space. Sometimes we'll go through one of the intercoccygeal segments, but in this case for this patient, the most accessible space is the sacrococcygeal junction. However, we don't know if we're safe by using that view. So we initially place our needle, and then we have to quickly switch to a multi-planar image. In this case, this happens to be our safety view as well. So here we can see the needle just anterior to the coccyx. What we want to avoid is this. So when your colleague asks you how the procedure went, you don't want to say erectile. You want to stay away from the rectum. So the safety view is also known as the danger view. I always think of Austin Danger Powers, but more importantly, I think of my mentor, Michael's safety firm. So the safety view is to make sure that the needle is going where you want it to go, and it's not going where you don't want it to go. You only really want to advance your needle, you know, towards the end in that safety view. Otherwise, you can't be confident that you're in a good place. So here's another example of the safety view of the ganglion impar, and some of the structures that you don't see. So you don't necessarily see the gas, sorry, the gas in the rectum or stool. This is your ganglion impar here. So you want to make sure that that needle is just anterior to the sacrum and not beyond. For a transforaminal, the safety view is going to be an AP, and we want to make sure that the needle is not going beyond six o'clock on the pedicle, because then you may get a dural puncture and intrathecal spread. For the caudal, this is one of your multi-planar views. Some people use this as a trajectory view, but I would argue it's not a trajectory view because it's not showing you your initial needle placement. So this is one of the multi-planar views, but we're not safe until we can ensure that the needle is no further superior than S3. And S3 is denoted by the inferior margin of the sacroiliac joint. So I would argue this might be a little superior, but you definitely don't want to go above S2, where the phylum terminality is. So our contrast views are going to be here. Here's our optimal view, and you can see on the lateral and the AP, we have contrast spreading nicely along the anterior margin of the coccyx and then spreading sort of in the midline. It's not going off to one side or the other. Here's a suboptimal view. So the needle's in what looks like good position, but then as we place contrast, we can see that we're getting a discogram. So that's great if you're doing a sacrococcygeal disc injection, but if our goal is to get to the ganglion impar more anteriorly, we have to advance our needle. So here's an example of what seems to be a successful L5 transforaminal, but as we know, one view is no view, and a common firmanism is the intersection of two lines is a point. So in reality, this needle is actually in the zygopophyseal or the facet joint. So on this lateral, you can see some subtle clues that we may not be exactly where we want to be. The needle looks like it's at the right depth, but you can see tissue here and here. So that's probably the superarticular process. We're seeing two of them because it's not a true lateral. So when you don't have a true lateral, the needle may be more anterior than it really appears to be. As we place the contrast, we can see there's contrast in that facet joint. So if you put a tiny bit of contrast in, and you immediately get inferior flow, you see this inferior facet recess opacified, means you're in the facet joint, you're not epidural. Now, if you see medicine spreading more inferiorly along the medial sacral wall or more superiorly, then you know you're epidural. Now, sometimes you're half and half where you're part in the facet, part epidural, but the goal here is to be epidural, not in the facet. So now we're going to move on to needle driving. And we're going to talk about the anatomy of the needle. So typically we're using a quinky needle, and this is the opening here. Some people use a Whitaker needle. These have more of a pencil point tip. So these are harder to drive, and the opening is further distal. So this is more, these are used in anesthesia, especially for spinal anesthesia, to prevent a wet tap. We're going to discuss bevel control, and that's basically using the natural pointy end of the needle to drive the needle. We're also going to talk about the concept of leverage, which is where you move the hub one way and needle goes the other way. And then concavity, which is sort of our, our hell Mary, when the needle's not driving where we want it to go, that's what we use to get more aggressive movement. So the advantage of using bevel control leverage concavity is that you don't have to keep taking the needle in and out. You don't have to get a perfect trajectory and then advance the needle five inches to your target, because even if you're doing a great job, the needle is going to deviate to some degree because naturally it's going to deviate away from this pointy tip or away from the notch. So you want to use that to your advantage, and that way you can make more drastic maneuvers as you're deep in the skin without having to remove the needle necessarily. So smaller needles like a 25 gauge are going to respond more to bevel control versus larger needles, like an 18 gauge TUI, they're going to respond more to leverage. So here we can see by bending the needle, we're going to accentuate that bevel control. So with the notch in this position, the needle is going to deviate away from the notch away from the bevel and towards that pointy tip. Now for doing interlaminar procedures, often where you're going to use a TUI needle. So the TUI has a curved end opposite the bevel, and because these are larger and they have this curve, they're not going to deviate as much. So the TUIs behave more with leverage. So basically we take our hub and we move it down and the needle tip is going to move up. Finch needles or SMK needles, these are used for radiofrequency ablation. These, for whatever reason, have the notch on the same side as the pointy end. So these needles are going to deviate towards the notch, not away. So just keep that in mind. So this is an example of bevel control. Here we see our needle is deviating using a clock face towards the nine o'clock position, and that's because our notch is at three o'clock. So if you want the needle to move more cephalad towards 12 o'clock position, you see now our notch is at six o'clock. So driving a needle, I'm sorry, we're going to go into concavity now. So normally the needle is going to create a fulcrum when it hits the skin. So if this is our target here, intuitively you would think, okay, well, let's try leverage. Let's move our hub to the right. That needle tip should move left to attack that target there. But what happens is the needle creates a fulcrum at the skin and counterintuitively, sometimes the needle will actually deflect and go away from the target, not towards it. So what you want to do is create that finger fulcrum above the level of the skin, basically by choking up on the needle and creating the curvature more proximally. That way, the needle's already deviating up here. And so by the time it gets to the skin, it's already turning towards your target. To use concavity, we have to use higher gauge needles, say a 22 or a 25. But again, this is your Hail Mary because once you use concavity, sometimes the needle will get bent and then it's very hard to steer it and hard to use bevel control. A more advanced technique is going to be your curve needle. And this can be used for discography to minimize infection or for things like transforaminals that Dr. Creighton's going to go into more in the next talk. So the key here is having that injection needle come out of the bevel in this orientation, because if your bevel is flipped, this needle is going to hit the notch, I'm sorry, hit the point here, and it's going to bang against that and not drive. So these notches have to be on opposite ends. So in summary, we talked about the algorithmic approach, regardless of how difficult the injection is, following a standardized progression can help you do things safely and effectively. We want to individualize the setup for each patient. Remember our trajectory, multi-planar, and safety views and our contrast views, both optimal and suboptimal. Bevel control, it's like driving a car. You want to use leverage, needle concavity, when you get into a bind. 18 gauges, larger needles are going to respond more to leverage. Smaller needles, like 25 gauges, are going to respond more to finesse. So now I'd like to introduce our next speaker, Dr. Roger Liu. Good afternoon, everybody. I'm Roger Liu. Nice to meet everybody. Hopefully that was an engaging first talk to the talk. Let's just get started and get right in there. So I have no disclosures. My objectives today are to discuss lumbar and cervical interlaminar epidural injections. We're going to learn how to optimize multi-planar imaging for safety. We'll also discuss, as Dr. Kirschner mentioned before, certain techniques that are sort of more probable to help you, such as leverage and finger depth gauge when driving toing needles, as opposed to clinking needles, as well as to compare lateral and contralateral oblique safety views. So starting off with the lumbar interlaminar epidural, what you see before you is a left paramedian approach. And basically, there are different ways to do this. A lot of times for beginners or for some practitioners, they prefer to actually walk off the lamina. So you're actually trying to aim for the lamina here as your target. And then once you hit bone, you know that you're not too ventral. So then you just redirect the needle from there. However, this could be painful for your patients. So the method that we use here is just staying interlaminar with your coaxial view and your hub view and using safety views to actually, you know, make sure that you're safe and then using loss of resistance to confirm placement. Doing it this way and actually add a bit of obliquity, like five degrees in this situation, it helps you avoid the supraspinous and intraspinous ligaments at midline. Now, while there's nothing wrong with having a needle traverse those ligaments, it could be, it could feel awkward in a sense, because you can feel like you're going through ligamentum flabum, even when you're posterior. And so a lot of times when you're going through muscle on the way to ligamentum, it's a more obvious change in what you feel. So for this first case here, on the left, we have a, what seems to be a coaxial view of your needle and it appears hub view initially, but in the second image, without moving the needle, you see a radically different image. So why is that? So when we first started with this procedure, our job is to actually, you know, maximize the area covered by the interlaminar space. By doing so, a lot of times the spinous processes, they slope downward. So we do often employ a bit of a caudal tilt and doing so is going to move the spinous process a little bit upward based on how it changes the fluoroscopic image. I've actually outlined the spinous process in red and the lamina in green. And so you'll notice in this view, the interlaminar space, it is large, but the end plate of L5, the superior end plate is actually not lined up. So, but it's good because it gets the spinous process out of the way. While in this spine, you know, it won't make that much of a difference, you know, the space is rather large. In a more stenotic spine or degenerative spine, where the adjacent laminae are too close together, are very close together, it may make the difference. However, when we confirm our imaging right before we infuse contrast, sometimes we go to a straight AP. So here, you notice some salient differences. For one, the blue arrow is to denote that the superior end plate of L5 is now more lined up because we employed, we took the caudal tilt off, which effectively is imposed a cephalad tilt on the entire spine. That being said, also pay attention to the spinous process. Now it appears to have kind of like overlapped more with the lamina. You see the red circle kind of go down a little bit. And you also see that instead of a hub view, you actually see the needle, more of the full length of the needle at this point, because of how much we changed the head tilt. All right. Lastly, instead of being more at midline, now the needle tip appears a little bit more lateral because the obliquity has now been removed. So the image on the left, it were a little bit oblique to the right side. So the actual pedicle, I'm sorry, the pedicle on the right is in the left are not equidistant from the spinous process. But here in a confirmatory AP, you see that they're more equidistant. All right. So moving right along, you start the procedure and you see this image. And, you know, the question here is, how will you adjust the needle to get a hub view? So before we get started with that, I like to sort of mention what Dr. Kirschner also mentioned before this clock face, you know, three o'clock, nine o'clock, 12 o'clock, we sometimes use a clock face to describe where we want the needle tip to go. So, you know, in all procedures, we tend to say 12 o'clock is superior or cephalad and six o'clock is more inferior or caudad. But whether or not nine and three o'clock drives your needle tip lateral or medial, it all depends on the laterality of the procedure. So it's really important to get this language straight before you start, especially if you have another practitioner or a trainee in a room with you. So here, if we were to drive the needle tip towards nine o'clock, we'd be deviating laterally, which is not what we want. We want to go superior medially. So here we would keep the two-e bevel at around eight, nine o'clock. And, you know, even though it doesn't really confirm much when it comes to helping us get there, which is bevel control, given that this two-e is a two-e needle, it's also a 17 gauge needle. We still want to optimize where our bevel's pointing, but then the real reason why it goes to where we want it to go is when we leverage the actual hub of the needle, which is outlined in red, down towards say eight o'clock, and it'll drive everything more super medially. And the end result is a better hub of ground. So here in this case, let's say you see this picture while you're advancing the needle. All right. And we're going to talk about, you know, two different adjustments we can make. So this is your AP image. It's a little bit oblique to the right. This is a right paramedian interlaminar. What do you do if this, if you see this image and your needle is still very posterior, you know, you just got purchased, there's plenty of paraspinal, you know, to go through, versus if you're actually quite deep and you're about to encounter lamina. So in the first situation, it's quite easy. All you have to do is just leverage the actual hub of the needle down inferiorly to about six o'clock and try to, you know, get it that way. And because you're so far away and you're not abutting anything, it should correct. The second situation is, you know, let's say you try to advance and now you're actually hitting bone. As you can see, I've outlined the lamina and it's outlined in red. So you see just how close is needle tip into that. You can't actually go more anterior after that, if you're already contacting bones. So you have to make a larger adjustment. And this is a situation where we employ finger depth gauge to correct this situation. And what finger depth gauge is, if you pay attention to how many, I guess, increments are showing in the initial needle placement here in the top left corner, you see, you know, two dark and two light increments. And what we're going to do is we're going to choke up needle and sort of grab it where it enters the skin. And when we withdraw, we have to take care not to move where our finger position is on the needle, because once we re-advance, we have to go and stop once our fingers encounter skin again. Doing an adjustment or performing an adjustment this way has a few advantages. For one, you do save on some fluoroscopic imaging and radiation because right now doing it this way, when you take your hands off, your needle will be at the same depth, give or take, that it was originally despite the large adjustment. But you can imagine, you know, if I were to just withdraw the needle and then let go of it, and I have about, you know, one or two more inches to go, when I re-advance the needle, I do need to take some extra pictures to account for that. So it may save you some radiation in the long run, which is good. All right. So moving right along, we're gonna take a few minutes to talk about safety view. In the lumbar spine, the lateral versus contralateral oblique, those are two ways that you can sort of have your safety view to check the depth of the needle tip prior to infusing contrast and also getting loss of resistance. Starting off with the lateral view, what you're looking for is the spinal laminar line. So I've encountered, I sort of outlined this in blue, and it's sort of this invisible line, obviously, that connects adjacent spinous processes. And basically what it represents is the posterior margin of the spinal canal, where one begins to encounter the ligamentum flavum and engage it, assuming you're at or around midline. You can also see circled in green, the inferior articular processes of the facet joints, and in red, the spinous processes. So basically, so the take home message here is your needle depth is always going to be relative to the spinous process and the base of it. And of course, if those of you who are relatively new to this, if you're looking at the, I guess the unmarked image in the top right corner, and you're wondering to yourself, gee, things are kind of a little bit murky, it's not a great lateral. This is why sometimes people don't like to use this and they use CLO as well, but this is also why this procedure, you need both the imaging and loss of resistance to confirm placement. One last pro is, when it comes to the lamina, if you look at where the lamina is outlined in purple here, you'll see that it slopes anteriorly. So the ligamentum flavum also slopes anteriorly, which also means that if you, if your needle engages ligamentum at the midline, it's pretty accurate when you get the lateral, but the further lateral you go, when you engage ligamentum on the lateral view to confirm, your needle will appear falsely deep. You won't be too deep because you'll still be posterior to ligamentum, but it'll appear like that. So sometimes that can be a little bit nerve wracking. Also, if you're way too lateral, you are at increased risk of being vascular and injecting into the posterior internal vertebral venous plexus. So we wanna hang around midline whenever possible. If you are going to use this technique, then you should know how to obtain an ideal lumbar lateral view. So an ideal lateral in the lumbar spine, you're gonna get maximal overlap of the pedicles in blue, the pelvic lines or iliopectinal lines in red, the superior articular processes, which is facet joints, because they overlap with the inferior in green. And you also want the end plates to square up. So this is a pretty good lateral that we see right here, but it's easier to just say this stuff, but it's harder to actually know how to troubleshoot. So Waring had a paper in 2020 where he compared, pretty much it gave us a good breakdown into how to obtain the perfect lateral. And really what you're taking advantage of is axial rotation or obliquing or longitudinal rotation or wig wagging. And so doing so, each movement is going to optimize two different things. So obliquing is gonna help you. If you look at the white arrows, it's really gonna help you overlap the superior articular processes, as well as the pelvic lines. And the longitudinal wig wag is gonna help you orient the end plates as well as the pedicles, all right? So just those two movements, if you see like a non-ideal lateral, just play around with that and it'll help you get there. Now, moving on to contralateral oblique view, we just established that the lateral view, you're looking for the base of the spinous process, the spinal laminar line, the contralateral oblique view, you're actually looking for a different line. You're looking for the ventral interlaminar line. And this line, you are connecting adjacent lamina. So outlined in red here, you see the lamina, the right side of lamina of L4 and L5 and in green, the lamina of S1, all right? So this injection was a right paramedian interlaminar. So we're doing the contralateral oblique. So this is why we're obliquing more to the left side here. There is some variability with people's anatomy. So, you know, typically you wanna oblique maybe 45 to 60 degrees contralaterally. And in this view, you should see a nice clear outline, all right, of the target lamina and your x-rays parallel to how it runs. And again, the biggest difference here is your needle depth is going to be relative to the lamina and not the spinous process. That also means that if you're a little bit further lateral relative to midline, it is a more accurate representation of a true depth, which we'll get into in a little bit later in the cervical spine, because you're not comparing it to the spinous process, which is at midline. Furman's atlas, Dr. Kirshner's atlas has a great schematic here. Here you see another CLO view. This by, you know, it's only different. The only difference is that the laterality. So we're CLO-ing to the right because it's a left-sided injection, but you do see the osseous elements and the neural elements here. But typically we consider a CLO view if you have a barren anatomy, if you have a patient with a large body habitus, or if you have a suboptimal imaging, despite many attempts to improve or patients moving around. And sometimes if you have false laws of resistance. So in a lateral view, if you're advancing, advancing, and you're thinking that maybe this is a ligamentum flavum, but it's really not, it's really, you know, thracolumbar fascia, you may want to go to CLO just to verify your depth. So in this patient, we encountered lamina. We walked off. This is after one adjustment using finger depth gauge. And this is after two adjustments using finger depth gauge. And here we, you know, because of the large needle, we were able to palpate that we were pretty much abutting the ligamentum flavum. We did loss of resistance. You see the slight difference there. I tried to put the location of the ligamentum in red. And then we instilled live contrast in both views of CLO and AP. It's interesting because here, there's usually a septum in the lower lumbar spine dividing left and right sides. And you can actually see the thin white line. And this is part of the reason why a lot of times, you know, we bias the injection one way or the other towards the more symptomatic side in a patient with bilateral symptoms to sort of take advantage of this and still deliver the medication epidural, you know, definitely getting to where we need to be. So moving on to the cervical spine, this is depicted here as a cervical interlaminar injection at the C7T1 level. A couple of things that are worth noting, the cervical spine, you know, obviously the area it covers is smaller than lumbar spine. And it's previously been shown that an interlaminar injection with a standard injector of six CCs, it does go up multiple levels. It does go down a couple of levels too, so four and two. And so for your patients with cervical radiculopathy, even if it's a little bit higher up, this is a good thing to sort of start out with. A couple of notes about, you know, the level of injection. Can you go a little bit above like a C6-7 or C5-6? Sure, but you do have to keep in mind that from a safety perspective, you know, the epidural space at the C7T1 level is really about two to three millimeters at most. And the higher up you go, obviously there's gonna be less and less space. Additionally, in terms of where you wanna be, dead midline versus a little bit off to the side. If you're dead center, sometimes some folks, they have an incompetent ligamentum at dead center. So you may have like a tricky, very subtle loss of resistance. So for that reason, when I do this procedure, at least I try to be a little bit lateral to straight midline. But here you see a couple of things. When we marked in the middle image, we marked where the blue dot is. But when we actually placed the needle in advance a little bit, we saw that we were a little bit off. Here, if you were to do the walk-off technique and your aim was to hit lamina first and to redirect, that would be perfect. But for us, we wanna avoid that, so we will have to redirect. One thing worth noting here is that we did employ a caudal tilt of about five to seven degrees to sort of open up the C7T1 space. You can see on the sample image on the left from Dr. Furmer's atlas that the C7 superior end plate is much more squared up, but now that we did a caudal tilt, we've lost that as depicted by the red arrows. So here we use finger depth gauge. We withdrew a little bit. We leveraged the hub of the needle at around two o'clock, and that's gonna drive the actual needle tip towards more eight o'clock. And as a result, our needle tip is now more midline and also more inferior, which is what we want. So this slide, when it comes to the contralateral oblique view, a lot of the literature that's sort of been published really touches upon the cervical spine. So the laminae of the cervical spine typically are oriented at around 45 degrees in both directions. And so this sort of explains, there's a lot more geometry than this, but for today's purposes, I think it does a good job. Basically, just taking us through the A through D on the left-hand side of the slide. In slide A, you have a right interlaminar injection. This is a T1 vertebrae, and you see that the needle does not actually change position in all three images. But where you are and how you're looking at the vertebrae, it changes the relative depth that it appears at. So in B, we have a lateral view. And so we're comparing the tip of the needle to the base of the spinous process, and that works great for now. But if you can imagine that needle moving off laterally and sort of engaging ligamentum a little bit further down, it's gonna appear really, really deep. Seeing here, basically, if you do ipsilateral oblique, and you're coming in from the right side, you're obliquing to the right, what you're effectively doing is that you're covering this much of the needle, and you're comparing the needle tip position to the contralateral lamina. And as a result of all the ways that you can do it, this will make this appear the deepest. So here we have the contralateral oblique, where the needle tip position is, your image intensifier is over here, as you can see over here, and it's actually comparing the position of the needle tip to the actual lamina that it actually traverses. So similar to lumbar spine, but these schematics typically have been published with the cervical spine, but the same concept applies. And here you have, from the ATLAS-2, just a schematic of the osseous elements, the neural elements, and another contralateral oblique. So with our patient now, we have a contralateral oblique view demonstrating a cross-section of the lamina, outlined in blue here and here, and also the ventral interlaminar line here. And we have withdrawn by a couple of millimeters here. And over here, let's say sometimes you're performing a cervical procedure, you could always give contrast early. So if you're unsure whether or not this is the ideal CLO view and you wanna make sure you're in a good spot, or sometimes people, when you go through muscle fascia, it can feel like you're encountering ligamentum. If you wanna be safe, you can always give contrast early. So in this patient, that happened to us, and we thought, okay, even though it appears posterior and we're pretty certain, we're gonna give contrast early and go here. So some people may sort of consider this premature contrastination, but really it's just a way to be safe, just a way to be safe. And over here in the bottom right corner, you see how the contrast pattern is really in the paraspinals. So after we were reassured of that, we actually did, we readjusted the needle, finger depth gauge again, we pretty much walked off the lamina, advanced. And then here we encountered ligamentum flabum, we did loss of resistance, and we were able to perform a successful injection. So that's CLO view in the cervical spine. And typically when you're performing cervical interlaminar injections, that's the view that you want. But there are cases where you would wanna do a lateral view for cervical spine as well. So when it comes to interlaminar epidurals, you can see here in this patient that the shoulder is always in the way. And the C7T1 level is oftentimes where we perform the injections. And so for other injections, however, here you see a radiofrequency, we do need the perfect lateral view. And so that also has certain criteria that we have to sort of cover. So for one, we have to have the transverse processes in the posterior superior corner of the vertebral body, and we call it the American flag sign, and that's outlined in red. You want the end plate squared up in green, and you also want the articular pillars or the facet joints to really overlap in two dimensions, superior inferiorly, that's orange, and also anterior posteriorly in yellow. And the last criteria is you really wanna maximize the distance depicted in blue between the spinal laminar line and the articular pillars. But usually when you do everything else and that's optimized, this is already optimized. And again, it's easier said than done. So in this person, you know, really the only true lateral is really at C5 here. You know, everywhere else, there's a little bit of adjusting that needs to be done. But luckily for us, you know, this procedure is only at this level. And so for our purposes, we're gonna document this one. And again, Waring, he did this for the cervical spine as well as lumbar spine. Here you see how, you know, just a little bit of obliquing or wig wagging can really get you there. So in the top row, you see how a little bit of obliquing, it lines up the articular pillars in the AP dimension. I'm sorry, in the anterior posterior dimension. And this in turn maximizes the distance between the articular pillars and spinal laminar line. Meanwhile, if you wig wag, you're going to overlap the pillars from the supra-inferior direction. And that way you have a clear border superiorly and inferiorly. And you're also at the same time going along with the end plates better, all right? Now you may have noticed that I put, you know, the transverse processes down in both. That's really because depending on how the patient's positioned, you may need a little bit of both. But by taking care of the other criteria, usually the last one fixes itself. So I know it was pretty quick, but hopefully that was helpful. In summary, Tui needles require more leverage and more finger depth gauge, and not, you know, really won't respond to bevel control. Certainly they don't have concavity. It's really much, you know, if you're strong enough to, you know, make concave a Tui needle, then you're pretty impressive. Ideal lateral views require more adjustment and needle depth can be misleading. Contralateral oblique views are an excellent alternative, especially in the cervical spine. Wig-wagging and obliquing are your friends. And remember, with interlaminar injections, you need both optimal imaging and loss of resistance with live contrast to confirm placement. So that's it. That's all I have. Any questions can be directed to us later. These are my references. And next up is my colleague, Dr. Creighton. Thanks so much, Dr. Liu. Next up is Dr. Creighton. All right. Hopefully everyone can hear me. Dr. Kirshner, I'm good? Can you hear me? Perfect, okay. Yep. So, like Dr. Kirshner said, my name is Drew Creighton. I'm an orthopedic surgeon. And I'm here to talk to you about how we can improve the quality of our patients' lives. My name is Drew Creighton, and thank you to both Dr. Kirshner and Dr. Liu for their great talks. I have nothing to disclose. And I'd first like to acknowledge Dr. Kirshner for his mentorship and for helping me with a couple of the videos that you're gonna see in this presentation here. So the goal today is to discuss, from my standpoint, the two-needle technique for lumbar transforaminal epidurals and case scenarios where this technique can be helpful. And to discuss key concepts of the often tricky scenario of lumbosacral transitional anatomy and transforaminal injections in this setting. We're gonna discuss PEARLS with regard to this and review different case scenarios that highlight these transitional anatomy concepts. So first topic, the two-needle transforaminal epidural injection. The case to keep in mind that we're gonna come back to is a patient that had had a prior L4-5 fusion surgery that now has bilateral lower extremity pain. So the two-needle technique, just briefly, is a common method, as Dr. Kirshner mentioned, to access the intradiscal space. It's also used to perform transforaminal epidural injections as we will talk about here. What it allows for is increased maneuverability to bypass barriers. So we're talking about hardware osteophytes, fusion mass to get to the target because an appropriately bent needle allows for, you know, allows to get medial with less ventral motion. So what does the setup look like? Well, you have this introducer needle, which in this case is an 18 gauge, one and a half inch needle. And then you have an injection needle, which for our case was a 22 gauge, five inch needle. And you can see in the scenario on the left that the introducer needle is a bit more superficial, which allows for a pivot point to go more medial at more of a superficial level, of course. But if the goal is to, or if you have a scenario where you need to get more ventral and less medial, then this can be achieved by getting the introducer needle more ventral, as you can see there. And that makes the pivot point where you go more medial further ventral at that point. So how do you bend the needle? Well, for those of you who haven't used this technique before, this is a video just showing and demonstrating how to bend the needle. So I'm gonna play the video here. Hopefully it will work. So what you can see is first that you're gonna identify where the notch is, okay? And then you're gonna bend the point basically of the needle away from where the notch is, okay? And one of the concepts that we're gonna come back to a couple of times just to reiterate how important this is, is if you're on the left side, if you're doing a left-sided two needle transfer aminal, you really want the notch to be at the nine o'clock position and if you're doing a two needle transfer aminal on the right side, you really want the notch to be at the three o'clock position. The goal is to drive medial. And if the notch is not at that three or that nine o'clock position, what can happen is that the needle can get too cephalad or too caudad in the coronal plane, which really can get you into trouble. So that is really a key concept to keep in mind. This is sort of an artistic rendering of the level that we're going to be going to here. And as you can see, there's hardware that's going to be in our way. What we didn't draw in here was a little bit of the fusion mass as well. And so what we drew on the right side here is a few scenarios. So the first one on the far left is where you have the injection needle here, the introducer needle here. And as you can see, there really isn't much of an oblique here. You're more straight AP. And with that scenario, you can see how you get ventral, too ventral. So with more of an oblique trajectory here, where you really don't alter the depth of the introducer needle at all, what you can see is that you're able to get medial at more of a superficial depth, but you're still too ventral. And so in order to combat this, what you have to do is you have to retract the injection needle. You have to retract the introducer needle as well. And this allows you to get to the place that you need to get medially. And at that point, you're less ventral, as you can see here in the drawing. So a different way to show this is with a video, and we're going to see here again kind of what we were just demonstrating. So here is more of an AP introducer needle. And you can see with the injection needle, you're overshooting the target. So now with more of an oblique approach, a little bit closer, but still too ventral. So you have to back out the injection needle, back out the introducer needle, which creates, again, a different pivot point or turn point where you can go more medial and at this point less ventral. And you can see that now we're able to get to our spot. So that's an example of sort of the move that sort of needs to often be made when you're doing this procedure. So when we're sort of pre-gaming before going in to do the injection, oftentimes obviously we look at different views on the MRI. So this is our patient, and you can see, first of all, the significant stenosis at the level above where the fusion is and why we're addressing the level that we're addressing at the 4-5 level with our bilateral transforaminal injection. And so where the localizer is is where we like to be cephalad, caudad within the foramen. But then you go to the axial slice of where this localizer is, and you can see what is ahead of us here. So there's quite a bit of, you've got the hardware and then also fusion mass around it here. But in this case, more hardware than anything. So one approach or one sort of way to think this through or a scenario that can happen and be ready for is, again, an oblique approach with the introducer needle and then the injection needle coming in. One of the pitfalls is that you can get too ventral. And so what you do is you retract the injection needle, retract the introducer needle, and now you can see that with a little bit more superficial introducer needle, the injection needle now arrives at a less ventral position and just as medial. So now to our case. So this is the initial AP, and you know that the pearl here is, you know that you've done a good job of squaring off the superior end plate when the pedicle screws at this level here are fairly parallel with relation to the beam. And if you look at the level below, you can see how these are more angulated. So this is a pretty good AP in which to start the procedure. So now we get to our trajectory look, and you can sort of see, yes, there's vertebral body over here. What's tough to appreciate is that there's also a fusion mass here. And you know, in a scenario like this, you really do want to get x-rays. You want to sort of optimize the imaging as much as possible beforehand and get as much imaging as you feel may be necessary, obviously being respectful for the radiation, just to best sort of quantify how much obstacle you're going to run into. So the key here is when you're putting your introducer needle in, you really want to be lateral to where you see most of the fusion mass and even the hardware. So that's where you see that we start here. Now you put the injection needle in, and with a little bit of leverage, you can see that here we're now traversing and going around this fusion mass here. So we switched our multi-planar imaging, and the injection needle has now popped through the introducer needle and is going in sort of a perfect line towards the eventual target. Now again, the key is, is that the notch here needs to be at the three o'clock position so that you don't get too self-led or too caught at here, okay? So as we stamp one more, you can sort of see that this arrived at the perfect six o'clock position. Now we go to the left side, similar story. You want to stay more lateral of where you see a lot of the fusion masses here. So we put our introducer needle in, again, trying to stay more lateral. Injection needle's now in, and again, we're popping through, as we can see on our multi-planar imaging here. We get to the six o'clock position. Now we switch to our lateral, and on the lateral, what you can see is that the needles are superimposed. So while the end plate here is square off, the end plate here is fairly square off, and you say, oh, this is a pretty good lateral. It's not helpful for what we're trying to see here. So the needles are superimposed. You don't know which needle is which, and so this is where the pearl of what we've talked about before, the wigwag, comes into play. So you wigwag, and you see, okay, this needle, there is one needle that seems to be a bit anterior. Turns out it's the right-sided needle that we did hit us on, and so what do we do? Well, again, you back out the injection needle, you back out the introducer needle a little bit. That allows you to get more medial and less ventral, and it allows you to get medial but less ventral at this point, and so again, we end up in what looks to be a good position here. Okay? Again, you switch to the lateral. You go to your wigwag, and you can see that the needles look to be in a better position, and this is our final AP, and you can see contrast spreading medially here on both sides. This is a shot after contrast has been placed on both sides, but kind of a neat technique and very valuable for our patient. Hi. How are you doing? Sorry, I'm in the middle of a couple of things and got delayed. What's going on that you need? So we'll keep going here. So the next topic is transitional anatomy, okay? And this can often be tricky. It can often be you don't want it to be, but if you're not ready for transitional anatomy, the worst place to find it is when you get down to the fluorosuite and you realize that you have a little bit of a different look than you normally see. Transitional anatomy can occur in about, on average, about 25% of the population, so it's something that we all will see quite a bit, okay? So this is the second topic that we're going to hit on. The first patient that we're going to talk about is one that was indicated for a same day procedure, pain down the right, the posterior aspect of the right leg was indicated for a single level transforaminal injection. And so, you know, this is sort of a common scenario that may pop up in our clinics. And what we see here on the imaging is fortunately the patient, you'll have to take my word for it a little bit. I can't show all the different cuts of the imaging, but it's pretty clear where the patient is having an issue. There looks to be a posterior paracentral disc herniation that looks to be at least a budding, if not irritating, the descending nerve at this level here, okay? And so, frequently with a single level transforaminal, what we try to do is address and approach this from the level below and bathe this nerve that's descending here and coming out here. So we try to access it here. And you know, I think the key is that, you know, one thing you notice on the lateral is that the transition from the lumbar spine to the sacrum is not quite as clear and there's what looks to be a rudimentary disc here. So it already starts making me think that there could be transitional anatomy here. And I think that the key is, is whatever you name this, identifying where the pathology is, identifying what approach and the reason why you're taking the approach you are and where you're going should be really well-documented so that everyone knows that a wrong level was not injected. And that's really ultimately the concern. One of the big concerns with transitional anatomy is that a patient gets operated on or injected at the wrong level. And that's really what we want to avoid here. And I think that if you pick the, you find where the pathology is, and obviously most importantly correlate it with what the patient is showing on their exam and clinically, and then you develop your game plan based on the imaging and how it correlates with the patient. The naming is very, very important, but identifying that level is really the initial priority. So fortunately this patient had x-ray imaging as well before the procedure. And so you can see here, one, two, three, four, five lumbar vertebrae. And whatever this segment looks like here looks to be, if you look closely, there looks to be a big transverse process here, big transverse process here. And still my thunder a little bit there, sorry for the early foot. So, and then on the lateral, you can also sort of appreciate again, this rudimentary disc here. So looking at the x-rays beforehand, again, very, very important to sort of make sure that you're identifying and approaching the right level. But is there something else you can do prior to going into the procedure or even during the procedure to better optimize this? The answer is yes, and that's the up tilt or Ferguson view. And this is a 30 degree cephalad tilt view that you can get even before going into the floral suite, if you're suspecting transitional anatomy and you feel that it would help game plan for your procedure, and you can see the difference. So this is a straight AP, this is your Ferguson view, and you can see that there's more of a head tilt here, and you can see how this nicely opens up the foramen, but also clearly better shows these enlarged transverse processes here that appear to be adjoining with the sacrum. So it was felt that this patient had a lumbarized S1. So on the procedure, even though we're sort of thinking along the lines of this looking like a lumbar vertebrae, what you can see is that you really don't, it sort of acts like an S1, and you really don't need to oblique that much in terms of identifying your trajectory view. And I think one of the pearls here is that these posterior elements can be hypoplastic. And so fortunately, that oftentimes results in less bone to be navigated posteriorly. So again, if you look at this lateral, and I don't show you the S1 here, you might think this really looks like an L5, and am I at the wrong level? So again, looking at imaging in multiple planes of motion, really looking at your imaging beforehand is very, very important. So this was the eventual AP that we got at the end, but one other pearl to mention here is that if you look at the pedicle here, if you look at the pedicle here, you can see some of the contrast shadowing over the pedicle here. And so that leads us to believe that to some extent, we were initially a 2 posterior. So you advance a little bit anteriorly, and then you get clear transforaminal epidural flow here. So the second case is a little bit of a different case. So patient was referred for a 2-level transforaminal by a surgeon who noted that the pain seems consistent with an L4 and or L5 referral pattern. And so you look at their imaging and take my word for it, that there's multi-level central stenosis as you can appreciate on the sagittal, but also multi-level foraminal stenosis. And you know, you got a little bit of a disc herniation that you can appreciate here. But the other thing that you appreciate on the lateral is, again, not a real clear delineation where the lumbar spine stops, where the sacrum starts. And again, what seems to be a rudimentary disc of sorts here. So is this L4, is this L4, is this L5? So I think that how can you inform that discussion when you're talking to the surgeon in terms of identifying the level that you're going to go to? Well, the one way to do that is with EOS full spine imaging. And if you don't have this imaging modality, it's essentially an x-ray that has significantly less radiation that allows for full imaging of the spine, which is pretty nice. The other thing though, that you can get is an MRI scout that will allow for counting from the whole spine. But that's really the best way to determine if you've got a sacralized L5, if you've got a lumbarized S1. So it was determined this patient had a sacralized L5. This was communicated with the surgeon. The surgeon was sort of on board and we were all on the same page in terms of what levels were going to be injected. Now, the thing that muddies the water even a little bit more is one thing to remember real quick is that the level-specific provoked symptom distribution during epidural injections is frequently different than that is predicted by classic dermatoma levels. So pain in the buttock, posterior thigh, posterior calf, it may be coming from L3, L4, L5, or even S1, according to the work from Dr. Fuhrman in 2019. And by the work of Dr. Kim in 2008, what they found was that in a case where you have a sacralized L5, the L4 nerve root serves the function of the L5 nerve root. So, you know, again, that may explain why sometimes we have to do injections multiple times and it also may be one of the many good reasons to address two levels as opposed to one level when you're doing an epidural injection to try to really help with someone's pain, especially in a case like this where there's multi-level stenosis. So this was the final AP and you can see the final resting place of the needle in AP. You see the contrast flow and, you know, you can see where you end up here, sub-pedicular like you would with any L5. So kind of an interesting look, but again, you know, really important to just review things beforehand. So just trying to get to the question part here, I'm sure there's some people that have some questions. So the critical points, really the value of the transforaminal epidural when you have hardware, fusion mass, osteophytes, the concavity with the two needle technique is really built in and you can really kind of control it and rein it in with the introducer needle. When you have transitional anatomy, you really want to treat the patient, determine the level of pathology as it matches with the patient and have a low threshold to get full spine imaging. And you really want to communicate with all members of the team, referring doctors, surgeon, radiologists. With that, we will go on to the question part here. Thank you so much, Dr. Creighton and Dr. Liu. Unfortunately, we have about five minutes left, so just time for a few questions. One of the questions is if we notice a difference between glass versus plastic loss of resistance syringe. So I'll defer to Dr. Liu to answer that. Sure, a lot of people feel like the glass loss of resistance syringe is a little bit more sensitive. However, preparing it could be a little bit, I guess, less convenient for the practitioner. So I was trained on plastic syringes, but a lot of times with the glass syringe, proponents of those really do swear by its sensitivity. Either way, you should feel comfortable with both and try both and see which one you prefer. One of the other questions was if Dr. Creighton could be able to identify which vertebra was called L4 versus L5 on the EOS spine view from the last case and how that view is helpful. I guess for the sake of time, I'll just answer for Dr. Creighton, the purpose of the EOS is really to count the segments. What you think may look like L4 may actually be L5, because in his case, honestly, I thought his L5 looked like S1. But that's where the EOS was so important, because when you count, it really was the way he showed it. Sorry about that, I was muted. That's OK. One question is, do we prefer CLO versus lateral for lumbar interlaminar? I use a little bit of both, honestly. Recently, I've been deferring more to CLO for the reasons I described in the talk. It's easier to have a CLO view versus an ideal lateral view. I prefer the lateral because I think it's more of an accurate representation, but whatever you need to see the anatomy to do it safely. The last question is if I could comment on the AP being the best safety view for a transforaminal as opposed to a lateral. That's a great point. With many procedures, there are multiple safety views. I would argue the AP is more of the safety view, because if you're too medial beyond the six o'clock position, then you could be intrathecal versus on the lateral. Yes, you could be too anterior. You'd have to be pretty darn anterior to be in a bad place. But certainly, if you're anterior to the vertebral body, you'll be in the aorta or be in a cava. So that definitely is a safety view as well. But I think the AP is probably more relevant. All right. Thank you so much, everybody, for your attention. We really appreciate it. If there's any other questions, my email is K-I-R-S-C-H-N-E-R-J, KirshnerJ at HSS.edu. And I'm happy to answer any others, and I can forward it to Dr. Wu and Dr. Craig as well. I hope everybody enjoys the conference. Look forward to seeing everybody in person next year. All right. Thank you to Dr. Kirshner for moderating and for organizing the session and to every one of you for attending. Thanks, guys.

spinal procedures

fluoroscopic procedures

systematic approach

needle placement

bevel control

multi-planar imaging

optimizing imaging

transitional anatomy

pre-procedure planning