Today we're going to be talking about navigating and troubleshooting cervical fluoroscopic procedures. I'm Namesh Bakshi. I'm accompanied by my colleagues here. So Jonathan Kirshner did his residency at Kessler and did his fellowship at OSS in York, Pennsylvania and moved on to become an associate professor at Hospital for Special Surgery. We all have clinical appointments at Weill Cornell Medical College. Jesse, after completing his residency, did his fellowship at HSS and myself. I also did residency in New York and Mount Sinai and did the same fellowship as Dr. Kirshner at OSS and I'm an assistant professor at HSS. So looking forward to talking to you guys about cervical fluoroscopic procedures and some tips and pearls. Jesse is going to be discussing cervical interlaminar and transforaminal epidural serum injections. I'm going to be talking about cervical medial branch blocks and ablation and Dr. Kirshner is going to be discussing C1-2 injections. So I'll let Jesse take the stage first. All right. I gotta shout out my residency. It's all about the U in Miami. All right. So today I'm going to be talking about, as he said, cervical epidural steroid injections. I have no disclosures. So the objectives of this talk is to discuss indications, goals of epidural injections, how patients may present. We're also going to discuss procedural pearls, whether or not they may have diagnostic value, what the efficacy and safety are of these injections, and lastly my approach to how I use them in treating patients. So some of the indications for cervical epidural steroid injections include cervical radicular pain with or without radiculopathy, post-laminectomy syndrome, acute herpes zoster associated pain, and patients who have had pain for at least four weeks, failed conservative care, or unable to tolerate. The most common causes of cervical radicular pain are disc protrusions with foraminal stenosis. Less common causes include tumors, trauma, infection, inflammatory arthropathies, and we always want to keep that in mind when a patient presents atypically or doesn't respond to treatment the way that we would expect them to. So clinically, a patient may present with pain going in a dermatomal distribution. Dermatomes may vary from patient to patient, although it does help key in to our suspicion of where a nerve may be affected. We also want to look for segmental numbness, weakness, and loss of reflexes to help identify which nerve is affected. Lower cervical roots are generally more affected than upper with radiculopathies. Mayo performed a series looking at a hundred patients with surgically verified radiculopathy and they found C7 to have a rate of 69 percent, while C6 was 20, and the remainder being C5, C8, and T1. I wanted to demonstrate these two pain mappings, the left from Dwyer's study looking at facet-mediated pain, and the right from Grubb looking at discogenic pain, just to show the overlap and how difficult it can be to treat patients with cervical complaints. So keeping in mind that a lot of things can present similarly. So my goals with doing an epidural steroid injection in the cervical spine is to reduce inflammation, both mechanically and chemically. However, there's no evidence that suggests doing an epidural will change the natural history of disc regression or immediately decrease nerve root compression. So what I try to focus on with the patients is we want to reduce pain and improve function, allow for natural healing to occur, and then making sure that the patient and I have the same expectations and goals for the procedure. I think this has a big impact on patient outcomes and satisfaction. So I'm going to talk about a case. The patient complains of shoulder pain. 32 year old male who has no past medical history comes in with a three week history of neck and left shoulder pain after overhead lifting in the gym. Patient complained of pain radiating from the shoulder down into the arm and his thumb. He endorsed having numbness along this distribution. He was taking naproxen 400 milligrams twice daily and hadn't noticed any improvement. The notable physical exam findings were intact strength, decreased sensation along the c6 dermatome on the left, diminished bicep brachioradialis and pronator teres reflex on the left, a Sperling's maneuver that recreated pain in the left hand, and an intact tandem gait and negative Hoffman's reflex. So my working diagnosis was cervical radiculopathy, but less likely differentials included impingement syndrome, thoracic outlet syndrome, and carpal tunnel syndrome. An x-ray was obtained that showed some degenerative disc disease at c5 c6 with some foraminal narrowing. I initially prescribed the patient with physical therapy and a higher dose of naproxen to take for two weeks. After six weeks of treatment with physical therapy going twice weekly, as well as completing the course of naproxen, patient called to say that the symptoms were unchanged. At that point we decided to get an MRI to further evaluate nerve root health. So the MRI revealed degenerative disc disease at c5 c6 with herniation, actually right more than left, even though he was asymptomatic on the right. On the left though he was noted to have severe foraminal narrowing with compression of the c6 nerve. Given his findings and lack of improvement with conservative treatment, we ultimately spoke about potentially doing an injection. So the question is which injection to perform? Ultimately I decided to go with the interlaminar injection, but let's look at the literature and see what it supports. So currently there's not a lot of literature pertaining to outcomes with cervical epidural injections. There's more in regard to interlaminar epidural steroid injections with eight randomized control trials as compared to three for transferaminals. However the transferaminal data is mostly observational studies with the randomized control trials not fulfilling Cochrane review criteria. So it's scant. The data that is out there for interlaminar epidural steroid injections is promising in terms of pain relief and functional improvement ranging all the way up to a year. We see several studies here that showed relief for over a year status post-injection. The one that I highlighted here is a study by Stav which did have a placebo controlled group that was non-epidural which is unique to the rest of these studies and they were able to do intramuscular injections and showed a statistically significant difference in outcomes with the epidural as compared to that intramuscular injection group. In terms of my approach with this injection I like to think of the interlaminar injection as a get-to-know-you injection. The reason being it's generally more tolerated by the patients. Positionally it's a bit more comfortable. If a patient has significant foraminal narrowing they may experience significant pain with the transferaminal and this could affect trust with the provider and poor expectations. I also look for multi-level spread of the medication although you can see this obviously with a transferaminal as well. Technically less challenging for me. Lower radiation and more efficient procedures. Both techniques have catastrophic complication risk so it's important to use significant safety and precaution with both. So if the interlaminar epidural provides relief but it's not sustained or no relief I discuss potentially moving to a transferaminal epidural steroid injection if appropriate. I do believe there could be some added benefit to doing a transferaminal injection just given the direct administration of medication to the pathology and ventral flow. However this has not been proven in the literature to this point. Safety must be taken regardless. So in comparing the interlaminar and transferaminal interlaminar you're going to get multiple spread. You may get some ventral flow although it's not a given and theoretically it is non-diagnostic because you're getting multi-level spread. Transferaminal approach could theoretically be diagnostic if given low levels of volume which we'll discuss later. It has a association with catastrophic injury due to vascular injection and injury although with digital subtraction, non-particulate steroid and a test dose risk decreases significantly. In talking about the interlaminar epidural I'm going to go through some of the procedural details. So first thing I like to identify the level that I'm going to be injecting. I want to maximize the radiolucent space so for this procedure it's the C7 T1 space. I'm going to caudally tilt or cephalad tilt accordingly. I then oblique towards the symptomatic side. So on the image up top you can see a coaxial view with the CRM oblique slightly and then how it looks on AP with the needle traversing towards the midline. Once the trajectory view is ensured and I believe I'm on the right path then I'm going to try to obtain my safety view. This can either be a lateral view or a contralateral oblique. I prefer the contralateral oblique and I'll explain why after this slide. So the contralateral oblique will be performed going to the AP and then 50 to 52 degrees contralateral to that point. This is to visualize the needle tip as it's traversing towards the ligamentum flavum and ultimately the epidural space. We want to make sure that we're rechecking the AP view if there's any concern that you have not yet had loss or you think you may have crossed midline. So things that I'm going to do prior to doing an epidural in the interlaminar space is a pre-procedure checklist. I'm looking at the radiographs and advanced imaging to check for several things. First I want to visualize my target, make sure that the location of injection is what I'm, you know, the ideal placement. I'm checking for ligamentum flavum to ensure that it is present, what its estimated depth is, and that it has formed union across midline. And I'm looking at the epidural space for depth and presence. I also want to know if the patient had prior surgery as this could affect the ligamentum flavum as well. So here I have a sagittal T1 weighted image. On the sagittal T1 weighted image fat's going to be noted to be white. We can see with arrows the epidural space here. We're going to see less epidural space above C6-C7 and this is why we encourage patients or providers to do interlaminaries at C6-C7 or C7-T1. I generally stay at C7-T1 but that can change depending on pathology. Aldrete looked at a hundred sagittal MRIs and found that there's significantly more space at C6-C7 and C7-T1 as compared to other cervical and thoracic spaces. So we want to make sure that we're avoiding high volume and high velocity, especially if patients have significant stenosis as this could acutely worsen the stenosis and cause cord injury itself. So other things that I'm always keeping in mind to limit the risk while doing a procedure in the interlaminar space is to keep the patient awake and sedate only if absolutely critical. This allows the patient to give feedback as well as you can then do a proper test dose to make sure that you're in an appropriate location. Avoid injecting at areas of stenosis. Try not to inject to cephalad as we know this is an area that has less epidural space. avoid high velocity or high volume injections, always use multiple views to ensure safety, and then the question of whether or not to use a catheter. So there's a study done by Goel in which he found that there's significant spread of 3.6 levels at C67 and 3.88 on average at C71 with as little as two cc's of contrast. So this calls into question whether or not a catheter is actually necessary, because you are getting significant spread with minimal medication. While the catheter has been proven to be safe, it does increase risk slightly, and if it's not absolutely critical, it calls into question whether or not we should be using it. So using the contralateral oblique will also help to visualize the needle and improve safety. So for me, I'm using the contralateral oblique, which is the picture on the right, and this is why. Dr. Gil performed a study comparing views in the contralateral oblique as compared to the lateral view. In that study, they found that visualization of the needle tip was insufficient in 13 out of 15 cases as compared to the contralateral oblique in which they had good visualization. The idea there is that with the lateral view, you're gonna one, have shoulders blocking the view, but also the image itself may not be sufficient. With the contralateral oblique view, they were looking at different angles to see what would be an ideal angle to do the contralateral oblique, and they did this by measuring what's called a measured contralateral oblique, which is shown in the top right image. They were then comparing where the needle tip placement ended up in the picture on the left to see which was closest to the actual ventral interlaminar line when it was at that ideal angle with a confirmed epidural injection. So ultimately, what they found was that there's a statistically significant difference between 50 and 45 degrees, 50 and 40, and 50 and 30, so 50 is the ideal contralateral oblique. The measured contralateral oblique may be slightly better, which was 52 at C6, C7, and 53 at C7, T1, although it was not statistically significantly different than 50. In their study, because their machine went to 50 degrees, they ultimately chose 50 and felt it was sufficient. I personally use 52 degrees, but one caveat I'd say is to make sure that you're doing that from the AP view and not from your oblique view, as this could make it unintentionally lower angle. If you do get a lesser angle, like 45, 40, 30, you can expect the needle to appear more anterior than it actually is, and it can give an appearance that you've gone too deep. This will cause you also to have early contrast or loss of resistance and potentially feel a false loss. If you're gonna go over oblique to 60 or 65 degrees, you have a higher risk of encountering the epidural space prematurely and causing some catastrophic injury or a wet tap. So these are images of the different angles, and you can see in image two, the anterior nature of the needle tip, that's with an angle of 30 degrees, and then it gradually backs up as we're obliquing more. Images seven and eight are lateral views, so you can see it's pretty difficult to identify the needle tip, although you can see the contrast is in an okay position, it's not ideal. So then I'm gonna talk about the transforaminal injections and that approach. What we wanna do is start by obliquing, identifying the proper location for the injection in terms of the level. Our target is gonna be the superior articular process, and as we said yesterday, bone is home, so you definitely wanna touch down on OS, and in doing so, you can be confident that you're safe and you're not gonna necessarily go too medial or avoid catastrophic injury. If you're not encountering OS in a reasonable amount of time or needle depth, always check AP to make sure that you're not somehow offline or causing to over-penetrate. So in these images, we can see the AP view. The most important image here for me with visualization of how I do these is the axial cut with the anatomy there, because we can see where the needle's supposed to go to the SAP behind the nerve root and the dorsal root ganglia. We can also see where the vertebral artery is and the dangers that we worry about, so how can we avoid that? So again, looking at the anatomy of this cross-section and thinking how a needle would come in here safely is critical in my mind. This is an image trying to demonstrate the risk of over-obliquing. So as we over-oblique, if you're coaxial, you have an increased risk of getting into that vertebral artery. We wanna make sure we are obliqued, but pointing so coaxial will touch the superior articular process, and therefore, it'll be a safer injection. Before the procedure, you're always wanting to look at the MRI and check where is the vertebral artery. Is it in a direct route to your target, which does happen on occasion, and if that does happen, you obviously are not gonna wanna do the injection at that level, and you either change levels to a location where the vertebral artery is gonna be cleared or change a route of injection, potentially going to an interlaminar. So again, just looking at the final placement, halfway through the articular pillar, or a quarter to a halfway, at which point you're gonna wanna inject contrast and ensure placement. This is another phenomenon called the hourglass phenomenon, and I just wanted to identify this for everyone because as we can see here, what you're identifying as the foramen may actually not be the external opening of the foramen. Not understanding this phenomenon could cause more medial placement than you would want. You have to understand that as you're touching down on os, because of the nature of the shape of this foramen, you could theoretically be slightly more medial. All right, so diagnostically, could this be used as what we like to call a selective nerve root block? This is a study done by Dr. Fuhrman. This was located in the lumbar spine, but the concept I'm gonna use in the cervical spine as well for the purposes of this talk. So what they found was that when injecting volumes as low as 0.5 mLs, there's still a 30% rate of involving adjacent levels. Therefore, for it to truly be selective nerve root block, it has to be less than 0.5 mLs of fluid. This could significantly impact the ability to do a therapeutic injection. When we get these referrals, I think it's really important that we speak with the surgeon and ensure that they're actually looking for a diagnostic injection, and that if that is the case, we kind of describe the limitations that we may have as a result, as many patients go to surgery based on these results. Just anecdotally, in talking to several surgeons at my institution, their understanding of selective nerve root block, it's pretty synonymous with just a transforaminal injection. So it's really important to educate your referral base and making sure that you, the patient, and the referral, you're all on the same page. So in terms of safety, things that we can do to help maximize our safety are we're gonna try to use contrast. Obviously, you need to use contrast in your epidural injections, and you're looking for vascular flow. Furthermore, digital subtraction to help visualize vascular flow in the cervical spine is recommended. I use a test dose of lidocaine to monitor for any signs of vascular injection for 90 seconds. I'm then asking my patients to move their hands and feet, checking for any sort of spinal block. I use extension tubing to avoid any needle manipulation, and use of non-particulate steroids for transforaminals. I don't use any sedation, as I want the patient to be able to give me live feedback, and avoiding blood thinners and anti-platelets. So this is a study, a very famous study from 2008, in which particulate and non-particulate steroids were injected into the vertebral artery of pigs. What they found was that all pigs that had particulate steroid injected into the vertebral artery lost consciousness and required ventilation support. They also, on MRI and histology examination, were found to have significant brain injury. As compared to the non-particulate, those pigs were asymptomatic and had no radiographic or histological findings of brain injury. So it really points to using a non-particulate steroid in the ability to decrease our risk of a catastrophic injury. Another paper that I wanna bring our attention to is a study done by the FDA in 2021, looking at all serious spinal adverse events found with epidural injections done on Medicare patients. So there was over 1.3 million patients that they looked at, or charts. For the cervical spine, there was about 170,000. It was split roughly 20,000 transforaminals and 150,000 interlaminers. Of note, there was no statistically significant difference between a transforaminal and interlaminar injection, although it was trending in the direction of transforaminal being more dangerous as compared to interlaminar. There was statistically significant increase in risk in cervical slash thoracic versus lumbosacral injections. What I found most jarring about this study was that the transforaminal cervical injections, 60% used particulate as compared to 40% non-particulate. I also found it to be interesting that 19% of the transforaminal injections that were performed in the cervical spine were done by physiatrists, but then interlaminers was only about 9%. So, and I have heard, you know, in speaking to anesthesia colleagues that they're less inclined, it seems, to do transforaminal injections. So it's just interesting to see the difference in training and subspecialty there. So in our case, as I said, I did an interlaminar injection. So as we spoke about, the needle tip is traversing towards the midline. Checked my contralateral oblique and injected contrast and had good epidural flow. So I was happy and the patient was happy. In the recovery room, the patient noted that his shoulder pain resolved. So diagnostic in the sense of, we know the diagnosis is likely coming from irritation of that nerve root, but not diagnostic in the sense of multi-level spread. Pain returned after the local anesthetic wore off, but ultimately faded with the steroid. Patient continued to report improvement up to six weeks post-procedure. So in conclusion, we want to make sure that we're evaluating patients to see if they're a good candidate for epidural. We then want to determine the best route of performing the injection to look at both the efficacy and safety. We want to pre-plan with reviewing images to avoid surprises and hiccups. And we want to communicate our goals for the patient to discuss realistic outcomes and have good patient satisfaction. A lot of what I used for this talk was from the Furman Atlas, the SIS guidelines and SIS website. Thank you. We're gonna try to leave some time at the end for questions. Okay, so I'm I'm gonna be talking about cervical medial branch blocks and RFA You know in going over These two procedures there's gonna be two themes that I'm going to sort of Repeat over and over as they were often repeated in our clinic and the floral suite in fellowship Number one is setup is key my mentor fellowship director Mike Furman was here Say this multiple times a day ad nauseum, but it's it's simple obvious But yet, but very important to remember a lot of what I'm talking about is going to be sort of Basic in a sense, you know resident fellow level, but hopefully there'll be some pearls that some of the veterans can take home, too the second thing is a quote by Henry Kissinger I don't know the exact context of this But he he did say if you don't know where you're going every lead will every road will get you nowhere So, we know that the goal of cervical medial branch blocks is to anesthetize the medial branch of a cervical dorsal rami and It's used to help diagnose where a patient's pain is coming from specifically if the pain is generated from an arthritic facet or a facet in general ultimately, the goal is to Consider the patient for radiofrequency ablation. So we know that the medial branches differ in in their location So the c5 medial branch lies Just in the lateral concavity of the articular process or the waist of the pillar and as we go caudal or cephalad that variation Increases so for instance the third occipital nerve the ton Sits near the c2-3 articulation the c3 medial branch really lies on the superior aspect of the articular pillar The anatomic location of the medial branches is important When you're doing these these procedures, so if you don't know where you're going the roads gonna get you nowhere So when we're doing this, there's two approaches to consider the lateral approach and the posterior approach I'm gonna be just talking about the lateral approach in many ways. I think it's technically less demanding especially for the upper segments Of course, the caveat is that visualization? Has to be excellent. So with the trajectory view being the lateral view the safety view is the AP making sure that the needle is not Veering off to medially to avoid cord penetration I do think that there's a safety component also in the lateral view ensuring that the needle isn't veering off to anteriorly Before we can even get to the procedure the very first part of the setup, which is key is patient positioning To get optimal visualization of the spine the patient needs to be positioned in a in an appropriate way So the neck has to be relatively neutral avoiding rotation. The shoulders have to be depressed as possible So on the left side, you can see my shoulders are kind of shrugged I have two pillows. My neck is sort of rotated and side bending towards the right And the corresponding fluoroscopy picture shows the upper the the upper segments relatively well, but the rest of the Cervical spine is is clearly blocked by my shoulders. So we added a pillow Put my neck into neutral. I relaxed my shoulders depressed them somewhat and you can see that on the corresponding for us for us could be picture below the The visualization is much better Sometimes we'll use cues like having the patient reach down to the pocket. Sometimes we'll have to manually distract the arms But without optimization of patient positioning the procedure becomes quite difficult. I've had to a number of times Change from a lateral approach to to a posterior approach just because the positioning was difficult based on the patient anatomy So Of course optimizing the lateral view is the second step After positioning the patient appropriately obtaining a good lateral it's gonna make the procedure go pretty smoothly. Hopefully Comfortable it creates a more comfortable Setup for the patient. So what are the components of a true lateral? Number one the articular pillars need to be superimposed right this the second Second criteria is that the transverse processes need to be in the posterior superior quadrant of the vertebral body. I call this the the American flag sign so the flags of vertebral body the the square that has all the stars is the Transverse process the disc spaces need to be clear. We want to try to maximize the distance between the posterior edge of the articular Pillars and the spinous process base or the spinal laminar line We have to sometimes adjust each segment based on the patient's anatomy how rotated they are how arthritic they are So yeah, so to optimize a true lateral, we sometimes utilize live fluoroscopy while obliquing or tilting to adjust for each segment. So you can see on the bottom, the fluoroscope is obliqued 20 to 30 degrees. And sure, on the first picture on the left, some of the articular processes look like they're superimposed, but there is no space between the posterior edge of the articular process and the spinal lamina line. You can see the foramen at C5-6. So this is not ideal. So as we oblique less towards midline, we start seeing the gap between the articular process and the spinal lamina line, but some of those processes aren't superimposed. And as we oblique even less towards midline, we're getting closer and closer to a true lateral at some of the segments. Especially on the right picture, you can start seeing the transverse process moving to the superior posterior quadrant. So the other thing to remember is there's very little real estate, meaning soft tissue is quite, there's not a lot of soft tissue to navigate through when you're doing this approach. So the course correction of the needle path needs to be undertaken quite early on in the procedure. The use of needle driving techniques like bevel control, the finger fulcrum technique, concavity, bevel control, I mean, yeah, the bevel control and needle concavity, that's all, that's very hard to use when the target is often two inches just below the skin. It's obviously important to know where your destination is, but you really have to start in an ideal position. So on the right, you can see that the safety view or the AP view, the needle does rest on the lateral concavity of the articular processes. If contrast is being used, you wanna see the contrast medium fill up that concavity. So in addition to patient positioning and obtaining a true lateral, we need to make sure that we readjust the C-arm for each level. So you can see here, we have the needles at C3 and C4 placed appropriately. Now we're working on C5, but starting off that procedure, the C5 segment is in the lower part of the screen, of the image. So what seems to be a relatively good trajectory in the middle picture actually turns out that we're much more anterior. We're hitting the transverse process. And some of this could be due to parallax. So parallax is the apparent change in the position of an object as a result of an incorrect viewing angle. So working in the middle of the screen really helps align the image. So in this case, the needle at C5 may appear to be in a reasonable position, but on AP, we see that it's actually not. So we were able to, of course, correct somewhat and obtain a much better picture, but again, it's really important to work in the middle of the screen. So patient setup is the first and foremost important thing that we can optimize. The second thing is obtaining a true lateral, knowing the anatomic locations of the medial branches that we're targeting. And it's important to avoid parallax. So moving on to RFA. Indications and goals for RFA is relief of pain after diagnostic block, hopefully lasting for 12 months or longer. So I just wanna go over a case of a C2-3 and C3 RFA. We know that off the dorsal rama of C3, there's a deep medial branch which innervates partially the C3-4 joint at a more superficial branch, or the third occipital nerve, which innervates the C2-3 joint. We know that the C3 medial branch runs across the upper half of the C3 articular pillar. The third occipital nerve is just across its apex, sometimes running actually just over the articulation itself. Typically for RFAs, for the lower segments, we want the electrodes to be inserted along a more diagonal, or a caudate to cephalad plane in the plane of the adjacent Z joint. The C2-3 joint runs much more transversely, more flatter. So it allows for a more transverse approach. Picture on the right just demonstrates the high, mid, and low needle target zones for an ideal neurotomy. So again, the third occipital nerve just runs in the upper segment of the C3 articular process. I'm sorry, the third occipital nerve runs at the articulation between C2 and C3, and the C3 medial branch is in the superior aspect of the articular process. Now it's just a matter of identifying the target on an actual patient. You know, you can optimize the patient positioning as much as you can, adjusting the amount of cervical flexion, mouth open versus mouth closed, but it could still be hard to see. So you can try to tilt the C arm maximally to open up the Z joints, the target level, in this case the C2-3. I like to identify the dens, or try to identify the dens first, and once you can see that, it's much easier to find the C2-3 joint, and then you can pick your target from there. Yeah, this is another good example of needing to know where you go. So you can see on the left, this is the AP view after a somewhat more oblique trajectory view was undertaken. I just don't have that picture here. So you can see the electrode is directed towards the C2-3 joint. But on the right side, you can see that the electrode is somewhat higher or more superior than the target zone. So we want to avoid missing the target zone. An incomplete lesion can, one, obviously lead to incomplete pain relief or short-term pain relief or no pain relief. Sometimes an incomplete lesion can also lead to neuritis or paresthesia. So we really want to be in the target zone. Challenge here, similar to medial branch blocks, is needle driving. Sometimes that can be difficult given the lack of pliability in the electrodes themselves and also the lack of real estate. So I just want to show you what we did next. Again, this is just to emphasize how superior we are to the target zone. And on the right is the final picture. The right side, these electrodes may look a little different. We're using needles that actually deploy these tines that extend the length of the electrode and create a bigger lesion size. So this is the journey. The needle was retracted and redirected only to be higher than the final endpoint. So I retracted a little bit and tried to redirect again to end more posterior than the target and superior and again and again. So finally, I had to really retract significantly, was able to direct the electrode inferiorly and finally reach my endpoint. I hope I'm not the only one in this room that has to course correct with these procedures and find it difficult at times. So moving on to cervical RFA of some of the lower medial branches. In this case, we utilized a more oblique view for our trajectory. But the challenge again is knowing where you have to go. Sometimes I'll take images of a patient before I start the procedure and really have no clue what I'm looking at, especially when patients have significant pathology. So I try to take a step back and identify some of the things that I do know. So again, the goal here is to target the C4 medial branch. By taking a step back and identifying things that I do know helps me identify ultimately where I want to go. So here I know that the rib, the first rib, is easily identifiable. We track that medially. And then I can identify the vertebral segment above the T1 vertebral body, which is C7. And once I see C7 much more clearly, I'm able to see the lateral aspect of the articular process at C6, C5, and ultimately C4. You can see the pointer here is just lateral to the target at C4. Oops, sorry. The other thing that sometimes can help is having the patient turn their head. So initially, the trajectory view that was shown here, the patient is turned ipsilaterally. I think for this particular patient, it was hard for her to turn to the contralateral side, so the chin is in the way. Sometimes the dental work can be in the way. In this case, it's not. But here we finally had her turn to the other side, and you can see the lateral aspects or the lateral margins of the articular processes much better. Ultimately, we got a good placement. And we're able to successfully ablate her. So that's all I got, setting up the patient, optimizing the trajectory view. In this case, we focused on the lateral approach. That's the most two important parts of the procedure. The rest is just knowing where you have to go, identifying the targets, keeping in mind the anatomic locations of the media branches. I just want to give a special thanks to Mike Furman, James Gilho, Paul Linden, and John Kirshner for teaching me everything I know. So I'll give it up to John to talk about C1-2. He's going to pull this up, right? All right. Thanks so much, Namish. I don't want to have feedback with both mics on. All right, so I'm going to be talking about C1-2 lateral atlantal axial joint injections. Just out of curiosity, who in this room performs these? Okay, great. So not the most commonly performed injection, but we have some experienced folks here in the room. So if I can throw you a little pearls here and there. These are my disclosures. Excuse me. All right, so I'm going to review the clinical presentation of C1-2 pain, review some of the anatomy, and then the injection approach. So this is a 75-year-old lady with posterior suboccipital pain. She has tenderness to palpation just anterior to the mastoid process. I always joke around, I'm an MD, my fingers aren't that smart to be able to palpate C1 and C2, but I know she's tender, very cephalad and laterally, and not over what I traditionally think are the C2-3 or C3-4 facet joints. She didn't incidentally have pain in those lower segments and did have a prior rate of frequency ablation, which addressed some of her lower upper neck pain, but not quite as cephalad as this current pain. She has significant pain and limited rotation to the left. No sensory motor deficits. So this is some of the relevant imaging. You know, it's important when we're getting cervical radiographs, you know, honestly, I don't get open mouth views on everybody. I don't get obliques on everyone. I want to reduce the radiation. So typically, my standard protocol for cervical pain is an AP and a lateral. If I know someone's coming in with a chief complaint of headache, and I think it could be cervicogenic headache, or there's trauma, rheumatologic disease, we see a lot in our institution, down syndrome, then I'm going to get the open mouth view to better assess the odontoid. So here you can see on that open mouth view, the left C1-2 joint is severely narrowed and arthritic. You can actually see sclerosis here on the lateral as well. Often those are hard to see. Other things you want to look for, widening of that AA joint, because if there's instability, typically with rheumatologic disease, that's going to be a big cause of C1-2 pain. And just getting osteoarthritis, you know, isn't as common in this region. You can see here, this is a STIR sequence. This is a fat suppressed sagittal MRI. You can see there's significant edema, not only in the C1-C2 articular pillar, or sorry, in the joint itself, there's an effusion, but there's edema in the articular pillar. So often there's some bone stress reaction as well with these. So, you know, how do we make the diagnosis of C1-C2 pain? SAS guidelines for cervicogenic headaches. So this is all headache arising from the C-spine, include the following features. So typically a unilateral headache, unless they have bilateral pathology, pain starting in the neck that then radiates either to the head or to the shoulder down the arm, and any of the three findings. So pain triggered by neck movement, sustained awkward posture, and or external pressure of the posterior neck or occipital region. So our patient had pain with rotation, pain with palpation, reduced range of motion of the neck. Pain episodes tend to vary in duration and fluctuate. Typically it's a non-throbbing nature, and there may be a history of trauma as well. So what's the role of injection? You know, as we know with many syndromes, we can see abnormal radiologic findings, but how do we correlate that clinically? So the C1-C2 injections can be very helpful both diagnostically, maybe moderately helpful therapeutically, we can get into that. So April did one of the landmark studies in 2002. For people who he suspected had C1-C2 mediated pain, 62% of them had relief of their headache when he injected them. Later, Nehruz did a similar study, and he basically took all comers with cervicogenic headache and injected different areas. So he injected 32 of these patients, and 15 had complete relief, suggesting a prevalence of about 13%. Govin did a similar study and found about an 8% prevalence, and in Bogdak about 9%. So because they're not necessarily injecting everybody with cervicogenic headache and doing controlled blocks at every single level, this may be an underestimate. So we may be under-diagnosing this condition. So these are some of the pictures from April's study. The picture on the left in A, these are the pain drawings of the patients that had a positive response to the injection, and B are the non-responders. So there are certain themes in common, others not so much in common. Anyone who looks like they're wearing a cape over their head probably is not going to get better with a single block. They may have multi-level pathology. But typically these unilateral symptoms, suboccipital symptoms. But interestingly, unlike CT3 facet pain, which often has that ram's horn distribution, these patients often have ear pain, lateral head pain, pain at the vertex, even eye pain. So you may have someone, you think they may have a cluster headache or other things like that, pain behind the eye. That could actually be C1, C2. Cooper did a study in 2007, which was really neat. He had patients draw where their pain was, then did controlled blocks at multiple levels, and wanted to see which areas got better. So for patients that had a positive response to the C1,2 injection, if their pain was here, it got better 75-100% of the time. So that tends to be my experience. I don't know for those of you in the room who do these, but often when a patient has pain here, you're starting to think C1,2. Versus if someone has pain down here, that's probably less likely going to be relieved from that block, but it's possible. So safety considerations. Should we do these at all? There's arguments about doing that. Cerebrovascular events, strokes, death from these procedures. So with any cervical procedure, any injection in general, obviously you have to respect the neck. I'm a Wu-Tang fan. Protect the neck. Be careful when you're doing this. Should we be using particulates? When I do these procedures, I'm using dexamethasone exclusively. For patients that don't respond to that, the question is, do you switch to a particulate? That's controversial. We can talk about that. The vertebral artery is going to be the main thing you want to avoid in this region. That's going to be located laterally, but often, of course, it's just posterior, adjacent, basically right in the path of the needle. The C2DRG is going to be medial to that, and then your thecal sac is going to be just medial to that. Also, these patients tend to have short-term relief. There's no real radiofrequency ablation target, unfortunately, for this joint. So often these patients need repeat injections. So these are the views we're going to use in our typical procedures. So starting with our trajectory view, the challenge is really optimizing that image. Namage did a great job of showing placement is really important, how the patient's laying on the table. I use a cervical positioning pillow, so the patient has their neck extended. They're comfortable. Some people use multiple pillows under the forehead, and you may want to adjust just the flexion and extension of the head. What's really important is the patient has to be able to open and close their mouth. That's one of the advantages of our cervical pillow is they can open it. In New York, all of our patients still wear masks. That's our governor's requirement because of COVID. So this is one exception where you let the patient maybe lower their mask a little bit. Let them be able to breathe, open their mouth, and the middle in the mask often shows up on the fluoroscope. So you may need to keep that in mind. So here we can see the structures that we don't see, but we want to avoid. So you can see your vertebral artery running just lateral, and this is a perfect diagram, but often there's variability of that artery, and sometimes it cuts right across the joint. So we want to break the joint into thirds. We want to aim for the junction of the middle third and the lateral third. It's recommended to touch down on OST here to know your depth and make sure you're not going too anterior before advancing into the joint. It's recommended to either touch down on that SAP of C2 or the arch of C1. I tend to touch down inferiorly and angle cephalad to get into the joint because I find I tend to start from a quadrat to cephalad angulation. If you're starting too high and then you go down, it's a little trickier. If you're starting cephalad, often you're going through the back of their head and hair, and I try to avoid that. So we sterilize that area well with Chloraprep, but I'm basically starting as cephalad as I can, ideally under the hairline if possible, and then advancing from there. So this is our multi-planar view. Here you're basically at the posterior aspect of the joint. SIS guidelines recommend advancing until you're at least a third of the way into the joint. With this joint, especially if there's gapping and stability rheumatoid arthritis, you can go through and through, and then the carotid is just anterior. So I'm not trying to go too anterior. Once I'm in, I'm happy. You tend to encounter the joint here and just advance slightly through, but SIS may say to go a little bit further, that we don't get extravasation posteriorly outside of the joint. Keep in mind what our goals are. Is it diagnostic? Is it therapeutic? Because sometimes you may get adjacent spread, but as long as you're in the joint, you're happy. So this is our initial trajectory view. It's one of those oh-ish moments where I can't see what I'm doing, and I've got this patient on the table, and I'm not going to abort the mission. So let's try to optimize our view. So the first thing we're going to do is collimate, and now already you can see that the image is getting a little better. What the CRM is trying to do is it's averaging the different tissue densities. So it's seeing a dense skull, the neck, and then the air on the side of the neck getting a little bit of lung, too. So the CRM gets confused, and it shoots out too much juice. So now it can focus itself and send out the right amount of x-ray beam. So here, we're still suboptimal as far as our imaging goes. You can see the patient's mask underneath that metal that's been lowered down. So we want to keep in mind, for this injection, we want to use a little bit of caudal tilt. The actual joint has somewhat of an AP angulation. So if you do go caudal, you may lose a little bit of visualization, but I find that it tends to help optimize the approach. So now we've done some caudal tilt. I think we're getting closer to a nice trajectory. It's still like you can't really see my target. So now we have the patient open the mouth. And now you can see there's a nice little opening right over here where we can start. So that happens to correspond to up here based on how she's laying. So I'm still starting a little more inferior. This is one of those where I'm sort of violating the pure coaxial view. But it's really important not to deviate your medial lateral more than one or two millimeters. I mean, this is not for the faint of heart and for the novice proceduralist. So we're advancing. We're touching on us. I'm flipping to my lateral view. As far as our safety view, this is our danger view. I was also trained by Michael Danger Furman. So I'm glad he's in the room here. So you don't want to go... Michael Safety Furman, sorry. You want to make sure the needle doesn't go where it's not supposed to go. There's no danger at OSS, only safety. So you only want to advance under that safety view. So your AP is sort of a safety view. Not really, because you want to make sure you're not lateral where the VERT would be, medial where the C2-DRG or the theco-sac would be. So really the lateral here is going to be your safety view. So this is our multi-planar safety view. I'm just at the posterior aspect of the joint. I've touched on OSS. I'm going to advance slightly into the joint. Sometimes you feel a little pop. This patient said, holy cow, that's the pop I feel every time I turn my head. Which is really neat. And then as I put the contrast in, she said, wow, that's my pain. So that's very gratifying for everybody. So here you can see outline of the joint. And you can actually make out a little bit of a meniscoid, which is normal in the joint. So there's a filling defect. I'm probably not pointing to the right spot, but it's hard to see from here. But there's a little filling defect anteriorly, and that's normal. That's a little meniscoid that's in the joint. And then one of the things you want to pay attention to is sometimes you're going to get flow coming up here. So sometimes, often, the lateral joint is going to communicate with the median joint or the contralateral joint on the other side. That's where you may lose some specificity. But if we want to be therapeutic, I don't necessarily mind if most of my medicine is going on the left and then some travels to the right. So when you see flow here, then you know it's going to that middle part of the joint. So here we can see on the AP, the contrast you don't see too well. So usually it's the lateral one I'm putting my contrast in live. This is another patient, equally challenging. If anyone has dental appliances, I learned this the hard way. Take it out before you start the procedure and the patient's prep, not after. These are implants, or caps. These don't come out. But for dentures and other things, I always do that. Pre-procedure, just checking with the patient, do you have any dentures? Let's take them out. So here again, we have the patient opening their mouth. You can see it a little bit better. So similar to the image, I'm trying to find the dens to localize where I'm going. And once I find the dens, then I get a better sense of where I am. So correlating with her cross-sectional anatomy, we see this artery in the way of our joint. So our target, and there's the artery right there posteriorly. So our target's there. So I'm trying to take that angled approach, so I can just avoid that squiggly vessel you can see right here. And so this is going to be my approach here. So if I'm too lateral, also I'm going to encounter the vessel. So I want to be at that junction of the middle third and the lateral third. At the place that corresponds to these slices here, basically, we have the vertebral artery right there. It's coursing basically posterior along the joint, and then it's going to travel up like that. So that's the corresponding coronal slice. That's just before I'm encountering the joint. This is the next adjacent slice coronally anterior. And now you can see the joint right here. And at this point, the vertebral artery's out of the way. So that's why I wanted to sort of sneak in underneath, staying medial, and I know I can safely get there. But I need to stay relatively inferior, and that's also why I like that caudate-decephalate angulation, because if I'm going more of a PA approach, I may be more likely to encounter the blood vessel. So here we can see we're in the joint, nice contrast flow. And here we're just seeing that horizontal outline, so that's not going to the contralateral side. This is another case where you can see nice lateral, but then on the AP, you know, Dr. Bogdove would consider this suboptimal if this was the diagnostic injection. This is suboptimal because, I mean, the joint patient got better. But you can see nicely on the AP that the middle joint and then the other contralateral side also filled. So these are my references. Thanks so much for everybody's attention and coming here early on a Saturday morning. We're happy to take any questions. Thank you. That's a great point. I mean, we want to put enough contrast in to be safe, but not overfill the joint. Studies show the joint holds about 0.8 cc's of fluid. You know, a lot of times there's some capsular laxity, and because of incivility in that area, it can accommodate more. Obviously, if you put more medicine in, it may go to the other side. So I'm typically using one cc of dexamethasone, and then half a cc of lidocaine. I'm not using any long-acting anesthetic, because God forbid if we get vascular or spinal block, I don't want to bag him for eight hours, as opposed to one hour. But yeah, usually with one and a half cc's, ideally you want to feel the joint filling. For this one, you don't feel it fill as much as say like other cervical or lumbar facets, I think probably because the medicine may spread to the other side. But typically one, one and a half cc's max. Lauren. What do you do when you get out of the hospital? That's a great point. So, I don't use a PrEP very often. I usually change the procedure so I can do something that wouldn't require contrast. For a procedure like this, you need contrast. So I probably would PrEP. Thankfully, I haven't done one of these on a patient with a contrast allergy, but I'd probably use PrEP. The gadolinium products are not really recommended anymore, so I try not to use them. But if the patient was low risk, I'd potentially have that discussion with them and maybe use gadolinium, but I would prefer not to. We have people that do CT guidance with these, but then they still need contrast. Do you plan to change the recommendation against using gadolinium for things outside of therapy? So, I mean, gadolinium can cause neurotoxicity and kidney failure. So the recommendations now, I believe by SIS, are to not use gadolinium products. I used to use it for people who had a contrast allergy. You don't see it as well as, say, Omnipake, but you could see it. I mean, I had a colleague who presented, we presented a case that the academy maybe 10 years ago of encephalitis caused by gadolinium, those inadvertently injected intrathecally. So the gadolinium, is that dose, is that like volume-related, or is it kind of volume? It's not necessarily volume- and dose-related. I mean, more is probably worse, but even with small amounts, you can have adverse reactions. Yeah. Yeah, you can also get idiopathic omeralone nephritis. Diabetics are a higher risk for that. That's a little bit volume-dependent, but yeah. I'd like to hear your guys' takes also, but no, I agree. I think that there's differing opinions. I personally don't use sensory testing unless there's just a placement issue, suboptimal, or I'm not sure with motor testing if there might be some radicular symptom. So I typically just use motor and move on to the ablation. The SIS recommendations are to do motor testing at a minimum. I do sensory testing on everybody, but you could argue, what's the value of that? I'd rather triple check and know. Maybe it takes a couple extra seconds, but I also work with trainees, so I think that's sort of part of the whole picture of understanding what's going on. If the patient were to get referred pain, I think it's sometimes educational of, oh, that's where the C4 referral pattern is, and things like that. But I have not aborted a case where there's a discrepancy between sensory and motor testing. I do a test dose of lidocaine, but then my injectate is a combination of steroid and saline. Some people mix lidocaine with the injectate and don't do a test dose, but then you sort of find out when it's too late. Others do the test dose and then add more lidocaine to their injectate, which is fine. The patient may be very numb afterward. Any other questions? All right, thank you so much. Thank you everyone.

cervical fluoroscopic procedures

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cervical epidural steroid injections

cervical medial branch blocks and ablation

C1-2 injections

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