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BackTable / MSK / Article
Basivertebral Nerve Ablation (BVNA) Procedure Technique: A Practical Guide
Thomas O'Rourke • Oct 31, 2023 • 210 hits
Basivertebral nerve ablation is a procedure that treats vertebrogenic and discogenic back pain with incredibly promising results. The majority of patients who undergo this quick, outpatient procedure experience a significant reduction in their back pain, with 30% of patients becoming completely pain free post procedure. Dr. Olivier Clerk-Lamalice, an interventional radiologist and pain management specialist, champions the effectiveness of this procedure and its post-operation outcomes. He also highlights some of the challenges he has faced when performing BVNA, and how to overcome them.
This article features excerpts from the BackTable MSK Podcast. We’ve provided the highlight reel in this article, but you can listen to the full podcast below.
The BackTable MSK Brief
• Basivertebral nerves (BVNs) both above and below the vertebral segment being treated must be ablated. When treating multiple levels, alternating the side of approach with the probe is best for ergonomic efficiency.
• The ablation probe should aim to be at least 1 centimeter ventral to the posterior wall of the vertebral body, ensuring a safe radius from neural structures.
• The BVN target at S1 is positioned in a way that the physician should approach about 50% anterior and 40% inferior to the superior endplate. This is distinct from other lumbar vertebral locations. A high riding pelvis or obstructions like the iliac crest can limit access to S1, indicating alternate techniques such as the transilium approach.
• BVNA typically uses light sedation, such as nitrox, supplemented with local anesthetic. This allows for shorter post-procedure recovery, with many patients ready to leave the clinic within 20 minutes.
• Studies like INTRACEPT and SMART indicate significant pain relief in patients, with about 75% experiencing a pain reduction of approximately 75%. About 30% of these patients may become completely pain free post procedure.
• BVNA is especially suitable for those with stable vertebrogenic or discogenic back pain, as they aren't ideal candidates for surgeries like TLIF or PLIF.
Table of Contents
(1) The Standard Approach to Basivertebral Nerve Ablation
(2) Overcoming Anatomical Challenges in Basivertebral Nerve Ablation
(3) Basivertebral Nerve Ablation Post-Procedural Care & Long-Term Outcomes
The Standard Approach to Basivertebral Nerve Ablation
Performing the basivertebral nerve ablation procedure is similar to vertebral augmentation. Dr. Olivier Clerk-Lamalice emphasizes the importance of the transpedicular approach, using an 8-gauge bevel or diamond-tip needle. Unlike traditional vertebral augmentation, where the needle is aimed towards the superior or inferior endplates, for BVNA, it's pivotal to center the needle within the vertebral body. This precision ensures the safety and efficacy of the ablation procedure. It is important to note that treating a single disc requires addressing two nerves - both above and below the vertebral segment, underscoring that no basivertebral nerve ablation is limited to a single level.
[Dr. Jacob Fleming]
Now it's procedure day, we have the patient. Tell us about what's the setting where you're doing the procedure and just walk us through the operation itself.
[Dr. Olivier Clerk-Lamalice]
Yes, absolutely. It's a very standard approach, so, similar as for many of us that do lot of vertebral augmentation. Basically, we're passing through a transpedicular typical approach. We'll be using an 8-gauge ear bevel or diamond-tip needle that we introduce via a transpedicular approach. The goal is really to introduce a needle up to the posterior wall of the vertebral body. Normally, you want to have an angle of attack also that is consistent to ensure that the ablation probe will be able to be exactly in the center of the vertebral body.
In comparison to a typical vertebral augmentation that you may want to aim for either the superior endplate or inferior endplates depending where most of the fractured cleft is located. For this one, you really want to be perfectly in the center of the vertebral body. That's a little bit of a technical consideration that adds a little bit to the degree of difficulty of the procedure. You may want to really proceed a little bit more slowly initially with this transpedicular approach that is safe in a neural avascular approach, very standard that many of us are performing on a regular basis.
You just really want to make sure that you're well-positioned within the pedicle. Just like, for instance, if you're doing a spine jack procedure. Basically, if you put implants within the vertebral body, same thing, you want to make sure that you have pretty much a parallel approach to the endplate, so whenever you deploy the jack that you can gain as much height as possible with the implants. Same thing, but in that case, you want to be parallel to the endplate but also just making sure that the tip of the needle is really in the center portion of the vertebral body.
Once the tip of your introducer needle is at the posterior wall of the vertebral body, you will introduce a nitinol J-Stylet assembly that is surrounded by PEEK (polyether ether ketone). This is a curved stylet that will allow you to go closer to the central portion of the vertebral body at the apex of the BVN. Then you push a spatula tip, and this spatula tip will create a channel in which you'll be able to push a bipolar ablation probe. The goal is really to try to reach as much as possible to be at least 1-centimeter ventral to the posterior wall of the vertebral body.
This is the reason why we wanted to have that, we want to have enough distance from any type of neural structure. Really, the initial bovine studies with this specific ablation probe demonstrated that most of the neural tissue damage was done in a radius of 5 millimeters surrounding the tip of the bipolar ablation probe. Then after that for another 5 millimeters, you may have some tissue damage. You just want to make sure that you have at least a safe radius of 1 total centimeter of safety where there's no other neural structures that you may be ablating. Then once you're well-positioned with the bipolar RF probe, you ablate for 15 minutes at 85 degrees celsius.
Quite a simple procedure. You need to repeat that actually at both the vertebral body, above and under the segments that you're treating. For one disc or one segment, you treat basically two nerves, so, the nerve above and under.
[Dr. Jacob Fleming]
Excellent. The aspect that there's no such thing as a one-level basivertebral nerve ablation procedure I think is crucial to understand, yes. Also keeping in mind that the access will be unilateral for each level because as long as you can target it in one way, just like doing a unipedicular or otherwise unilateral vertebral augmentation procedure, we don't ever need a bipedicular approach to target the nerve, which helps certainly. We did talk about how, for example, if the cause of pain were the L4,5 endplates, then you would be approaching both L4 and L5.
[Dr. Olivier Clerk-Lamalice]
Correct.
[Dr. Jacob Fleming]
Do you use a contralateral approach for that for ergonomic reasons, for example, accessing right side at L4 and left on L5?
[Dr. Olivier Clerk-Lamalice]
Absolutely. Normally, I would start on the left side for the superior level and inferior level on the right side, yes. Sometimes you may be able to go on the same side, but it can become a little bit awkward. My recommendation definitively it's to alternate basically. If you're starting on the right side, second level should be on the left.
[Dr. Jacob Fleming]
Sure. Is your approach to get each of the level cannula in place, and then try to burn everything at the same time?
[Dr. Olivier Clerk-Lamalice]
There are some international listeners and listeners also in the US. In the US, basically, the only system that is FDA-approved is the Relievant system. Currently, it is one nerve at a time that we proceed with the ablation.
[Dr. Jacob Fleming]
Sure.
[Dr. Olivier Clerk-Lamalice]
For international listeners, there's some other ablation system that can be used to have a similar type of outcome. Currently, in the US, yes, it is with the Relievant system, and it's one nerve at a time.
[Dr. Jacob Fleming]
Excellent. That would probably be the approach of getting the access and going ahead and treating and while that's burning, moving onto the next level, gaining access. I would imagine that's probably the most efficient way to approach that.
[Dr. Olivier Clerk-Lamalice]
Yes.
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Overcoming Anatomical Challenges in Basivertebral Nerve Ablation
Many of the challenges faced while performing basivertebral nerve ablation are due to anatomical differences. While the usual BVN target is located within the posterior third of the vertebral body, at S1 it shifts to approximately 50% anterior and 40% inferior to the superior endplate. S1 can also be obstructed by a high riding pelvis or structures like the iliac crest. This may necessitate alternative approaches such as the transilium approach. In patients with implanted screws and other devices, parapedicular and modified endplate approaches may be necessitated. Additionally, it is important to note that bone density, particularly sclerosis, can sometimes pose a challenge, potentially making curved interosseus approaches more complex. Understanding that BVNA requires a high level of anatomical knowledge and practical experience, and adaptability is paramount to patient safety and positive outcomes.
[Dr. Jacob Fleming]
Then one thing I want to talk about a little bit is obviously the L5, the S1 endplate interface is a common cause of this pathology. S1, of course, has some slightly different considerations from the lumbar vertebral bodies. Could you tell us a little bit about that?
[Dr. Olivier Clerk-Lamalice]
Yes, absolutely. The BVN target for the S1, it was a little bit different. Rather than being within the posterior third of the vertebral body, you want to be about 50% anterior and 40% inferior to the superior endplate. Slightly different location. I would say that in the majority of cases, it is not too much of an issue to find a target and put the G stylet in the right area. In some instances, a high-riding pelvis, it can be a little bit more challenging, but normally, you're still able to find a window there. There would be technically other ways to do it, but so far I haven't had any patient that I was not able to access there.
Slightly different. It does take a little bit longer. Just like for vertebral augmentation also, often the L5 vertebral body, it's a more aggressive approach depending on the lumbar lordosis where you're using longer access in trocar. Same type of issues that you're also seeing at the L5 level and S1. It's mainly related to the iliac crest that can sometimes obstruct the area, but normally you should be good to find some type of access.
[Dr. Jacob Fleming]
Very nice. I do want to give a shoutout to our mutual colleagues and mentors, Dr. Beall and Dr. Wynn. They had showed me some cases in which they utilized slightly alternate approaches which made the specific case due to anatomic reasons go much more smoothly or actually be able to proceed, whereas the specific issue may have complicated that. For S1, as you said, sometimes with a high-riding pelvis, getting that pelvicular access can be quite tough. Dr. Beall has described using several times the transilium approach.
This is just to tell our readers a little bit, it's basically going from a lateral approach through the iliac bone and targeting the BVN that way. This is something I think will make a lot of sense for radiologists who think in terms of axial, transaxial cross-sectional imaging. It makes a lot of sense to see, okay, it's much like a specific lesion biopsy to take the straightest path possible. That's an alternate method that certainly can be used. Of course, definitely, something only to use if you're comfortable with the imaging landmarks under presumably fluoro.
Of course, this procedure could be done under CT, but most commonly done with a C-arm. That's one way. Dr. Wynn has shared a case with me of a patient who had prior instrumentation with pedicle screws and had physical exam history and imaging findings that were concordant with vertebrogenic pain. Of course, getting transpedicular access when the pedicles are already occupied by screws is problematic. Using the parapedicular approach that has been described previously is an excellent way to do that as well. Of course, spine interventionalists are seeing lots of different kinds of patients with different inborn anatomic factors and iatrogenic factors.
I did want to throw out those. I thought those were some very interesting considerations. As radiologists, the interventional radiologists know it's not really an option for us. If there is a clinical need to do something, and there's a specific anatomic complication, we tend to find a way to work around that. Hats off to Dr. Beall and Dr. Wynn for bringing those to the forefront.
[Dr. Olivier Clerk-Lamalice]
Absolutely.
[Dr. Jacob Fleming]
We'll actually have a small presentation. This is some absolutely shameless self-plugging at the upcoming ASSR, American Society of Spine Radiology conference that, by the time listeners are hearing this, it will have already happened. We do have a presentation talking about some of these alternate approaches to use the BVNA. As you said, the wide majority of the time, the standard transpedicular access that's tried and true and familiar to many spine interventionalists is going to get the job done.
[Dr. Olivier Clerk-Lamalice]
Absolutely. I think this is the beauty of having a wide spectrum of intervention within a toolbox. We can use tricks and tools that you have learned through other type of intervention, so through time, if you're doing more, it becomes much easier. I completely agree with you that the transiliac approach is a great approach. It's a straight approach. It's a easy approach. We know we use it, for instance, for sequel extensive fracture. We use it to put screws, to put different type of implant of material. Especially when you can avoid to have too much curvature and just going in a straight pathway, it's always a little bit easier.
This is definitively a great approach overall also for your vertebral body. You're completely right. You can use a parapedicular approach. You can use a modified inferior or superior extrapedicular endplate approach. Depending where you want to end up, there's various ways to access the vertebral body to avoid implants, to avoid pedicle screws. The more you know, the more you do, and the more you're able to accomplish and put the needle exactly where you want to, and it becomes easier through time. These are very wise words and completely agree. Shoutouts to Dr. Wynn and Dr. Beall.
[Dr. Jacob Fleming]
Yes, definitely I agree with that. Always lots of wisdom coming from them, and so I did want to make sure to share that. We'll also try to share that presentation in the show notes once we have it available. We've talked about the procedure, some in and outs. Any other pitfalls? Any other issues you may have run into doing quite a handful of these at this point?
[Dr. Olivier Clerk-Lamalice]
Yes. The only other pitfalls sometimes is with the bone density, so, sclerosis. Sometimes when the bone is very hard, using a curved interosseous approach can be a little bit more tricky. This is still a minority of cases, and you're most frequently able to drill through it or access where you want to go, but these are the things that real-life experience will trick you at some point, but otherwise, it is a fairly straightforward procedure for those of us that are doing lots of augmentation.
Basivertebral Nerve Ablation Post-Procedural Care & Long-Term Outcomes
BVNA is an outpatient procedure that is typically performed under light sedation, such as nitrox, making recovery from the procedure brief. Many patients generally are ready to depart the clinic within 20 minutes. To ensure optimal comfort, an epidural steroid injection is sometimes administered post-procedure, serving as a bridge for pain relief. Key studies like INTRACEPT and SMART clinical trials offer insights into the efficacy of BVNA, showing considerable pain reduction for most patients. Moreover, long-term follow-up suggests lasting pain relief, challenging the status quo in back pain management and presenting BVNA as a promising alternative to surgeries like spinal fusion.
[Dr. Jacob Fleming]
I suspect this is going to be an outpatient procedure. What's the aftercare situation? When do you see the patients back, and are there any post-procedural considerations, peri-procedural care that you go over with the patient expectations, and things like that?
[Dr. Olivier Clerk-Lamalice]
Yes. That's an interesting question because I do have lots of interventional colleagues in different countries and continents. It's always interesting to see what is being done elsewhere in term of sedation and post-procedure recovery. We're not doing those procedures under GA. We're doing it with fairly light sedation. We're using a gas called nitrox to sedate patients, and just like a vertebral augmentation, we're doing it mainly with heavy local anesthetic. It's a very short procedure. I do a ton of these procedures. I would say that the patient will stay about an hour in recovery after the intervention, and then after that, they are good to go.
It's a very short procedure for most patients. Obviously, you have those patients with comorbidities or older individuals that may stay for a longer period of time, but I would say the vast majority, after 15, 20 minutes, they're ready to leave and they feel great. Just after a vertebral augmentation, I do an epidural steroid injection also just to provide some pain relief. Basically, the patient will be covered, and you bridge the post-procedural pain that they would normally have after an intervention until they do feel the relief. It does take a couple of days before they will feel better, but at least bridging basically this with an epidural steroid injection is also a good idea.
We know also that even for, not in all, but in a good portion of patients that have Modic Type 1 or Type 2 will have some type of relief with an epidural steroid injection, so really bridging procedural pain like this is part of our practice.
[Dr. Jacob Fleming]
Beautiful. Tell us about the degree of pain relief that you're seeing with patients, and how are you counseling them beforehand for expectations in terms of clinical success, and how are you defining that.
[Dr. Olivier Clerk-Lamalice]
Overall, there's two studies that's really evaluated BVN ablation. There's the INTRACEPT and there's SMART trial. The INTRACEPT followed patient for 2 years, the SMART clinical trial, up to 5 years and so a total of 473 patients are actually treated. Within all those patients, if we just summarize it, I would say 25% of patients have 50% of pain decrease, and the other 75% have about an average of 75% of pain decrease, and functional improvements. Within the 75%, you have about another 30% that are almost completely pain-free.
[Dr. Jacob Fleming]
Wow.
[Dr. Olivier Clerk-Lamalice]
That's very notable. Basically, I would say on average, most likely your pain will decrease for about 75%, and if you're within the lucky 30%, your pain may be completely gone, so, really good results. Again, we select all patients with what we discussed earlier, with an anesthetic discogram. Basically, we're just treating those pain generators that we know will respond well with the BVN ablation. That does help a lot.
[Dr. Jacob Fleming]
Very nice. As you alluded to earlier, there's some interesting unique aspects of the basivertebral nerve itself, specifically the non-myelinated nature. From what we're seeing from the data, it seems to be that for at least the majority of patients, this pain relief is long-lasting. It's not something like a medial branch RF where we'll tell the patient months or perhaps longer of relief, but the pain likely will come back. What's the current data on that?
[Dr. Olivier Clerk-Lamalice]
Yes. The 250 patients that were enrolled within the SMART clinical trial, at the end of the five years, I believe there was still 100s that were still being followed. All of them demonstrated sustained improvements in pain, quality of life, and function. It seems to be a permanent treatment. Even there are some of those patients that are now eight years out and still, it seems to be a permanent treatment. This was already fairly known with some of the ex vivo studies that ablated basically BVN, waited to see if there was a neural sprouting, if there was any type of neural healing, which wasn't the case.
It's one of those treatments, again, that I think is essential within a pain practice and does really change the course of management of patients because those patients, we haven't yet dig into that, but it is within a category of back pain that we call stable, either vertebrogenic or discogenic back pain. Those patients are not candidates for any type of TLIF, PLIF, any type of spinal fusion. Spine surgeons should not operate on those patients. There's no evidence of instability. Often, unfortunately, in the past, there has been quite a few patients that went to surgery for that because often the patients have no other solution, and they want to have something done.
I understand it from a surgical perspective that you try to help those patients, but now I think we have very strong Level 1 data that demonstrate clearly that, hey, there's a better procedure that takes around a half an hour to 45 minutes and that provides very reliable pain decrease and improvement in function and the patient will feel the result of that procedure within a couple of hours after the intervention. Doing a fusion and doing even a disc replacement for those patients should no longer be a thing.
Podcast Contributors
Dr. Olivier Clerk-Lamalice
Dr. Olivier Clerk-Lamalice is an interventional radiologist that specializes in interventional pain management and diagnostic imaging in Calgary, Canada.
Dr. Jacob Fleming
Dr. Jacob Fleming is a diagnostic radiology resident and future MSK interventional radiologist in Dallas, Texas.
Cite This Podcast
BackTable, LLC (Producer). (2023, June 18). Ep. 13 – Basivertebral Nerve Ablation [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
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