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BackTable / MSK / Podcast / Transcript #13
Podcast Transcript: Basivertebral Nerve Ablation
with Dr. Olivier Clerk-Lamalice
In this episode, Dr. Jacob Fleming interviews Dr. Olivier Clerk-Lamalice about basivertebral nerve ablation for vertebrogenic back pain, including indications, procedure technique and exciting tech on the horizon in minimally invasive spine interventions. You can read the full transcript below and listen to this episode here on BackTable.com.
Table of Contents
(1) Providing Comprehensive Care as an Interventional Radiologist
(2) The Basis for Basivertebral Nerve Ablation (BVNA)
(3) Procedural Techniques & Considerations
(4) Overcoming Common BVNA Challenges
(5) Post-Procedural Care & Long-Term Outcomes
(6) BVNA Integration into Daily Practice
(7) Future of Spinal Pain Management & Expectations Beyond BVNA
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[Dr. Jacob Fleming]
Hello, everyone, and welcome to The Backtable MSK Podcast, your source for all things musculoskeletal. You can find all previous episodes of our show on Spotify, Apple Podcasts, and on backtable.com. This is your host, Jacob Fleming, reporting from Dallas, Texas. Today, joining us from the Great White North in Calgary, we have Olivier Clerk. Dr. Clerk, welcome to the show, and thanks for your time.
[Dr. Olivier Clerk]
Thank you so much, Jacob. It's my pleasure to be here, and very excited to be talking about some interesting treatments of the anterior column today.
[Dr. Jacob Fleming]
Absolutely. Likewise, I'm very excited. We've been talking more about anterior column treatments, most recently with your colleague, Dr. Ed Yoon, and a recent episode talking about disc therapies. The topic today is related, and it's an exciting and emerging topic, which is vertebrogenic pain, and specifically, the basivertebral nerve. Really looking forward to talking about this with you and hearing about your experience and the international aspects, the perspective that you have. Before we jump into the topic for the day, I would like to hear about your background, including where you've lived and trained.
[Dr. Olivier Clerk]
Yes, absolutely. I did most of my, well, a good portion of my training in Canada. Before even starting in medicine, I did engineering for pre-med. Then I did medical school at the University of Sherbrooke. Sherbrooke is a city about an hour south of Montreal and a little bit north from Vermont. It is a quaternary center in which I did both all my medicine and residency in diagnostic imaging. After that, I pursued a fellowship in neuroradiology at Massachusetts General Hospital. This is really where I started to be further exposed to interventional techniques and spine intervention.
I worked actually with the great Dr. Joshua Hirsch and started to do lots of anterior column treatments and augmentation procedures, so, lots of vertebral augmentation during that fellowship. Then I did a second fellowship dedicated to interventional pain management. That was at the Spine Fracture Institute in Oklahoma City with Douglas Beall. This is where I further learned about new interventional techniques, did lots of neuromodulation, so, spinal cord stimulator, intrathecal drug delivery device, and among other essential procedures for our field, interspinous spacers.
After all that, just because I really fell in love with the specialty, I decided to pursue the qualification of fellow of interventional pain practice, so FIPP. Right now, I'm accredited both in diagnostic radiology and interventional radiology and in interventional pain management. In my current practice, I'm doing both the diagnostic aspect and the interventional aspect on a daily basis.
(1) Providing Comprehensive Care as an Interventional Radiologist
[Dr. Jacob Fleming]
Very nice. It's definitely a training pathway that goes a little bit off the beaten path in a few different ways. I liked that you brought up the FIPP designation, which is something that's interesting, I think, that radiologists who are involved in interventional spine and pain management techniques, a lot of us do that without specific fellowship training in that. People may come from traditionally VIR or musculoskeletal or neuroradiology and start doing these things. Since you had such extensive fellowship experience, you went for this international designation.
I think that that's something that really showcases to the interventional pain community at large, that as an interventional radiologist or radiology-trained interventionalist in the area, you really are dedicated to the full spectrum of it. Would you agree with that? What was the experience in studying for that exam and undergoing that certification?
[Dr. Olivier Clerk]
Yes, absolutely. I completely agree with that. I think as radiologists and as interventionalists, we're very well trained to diagnose images and proceed with therapies, but really, I think the FIPP designation really bring it to the next level and provide a really comprehensive approach to the treatment, to patient care, and really integrate also physical examination within, especially for the patient selection aspect. That's something that I think to have trained in diagnostic radiology, we're less exposed to. It is crucial, like, our outcomes are directly correlated with our patient selection, so you can do a procedure very well, but if it's not for the right issue, the right problem, you will not obtain the expected outcome for a patient.
Really for me, having the FIPP certification really did put everything together that, basically, for the patient that enters basically my clinic currently, I can clinically assess him. We can recommend basically which diagnostic studies need to be performed, read that study to a very high level, and then suggest interventions. That really becomes the true one-stop shop that you take the patient from as soon as he enters the clinic up to when he comes out of the clinic pain-free or with significant improvement. I think this is new for our specialty to be able to really follow patients like that.
It is the future, it is the way to optimize care, avoid having a patient that will go to various practitioner, various centers to be able to obtain the complete treatment. I highly suggest to interested individuals to proceed with that type of accreditation if they are interested in interventional pain subspecialty.
[Dr. Jacob Fleming]
Such an important perspective, I believe, that what you're talking about, it alludes to the old adage that we treat patients and not images. Yet for what we do as interventional radiologists, the imaging is obviously crucial, and so knowing where that fits in and knowing how to interpret all the studies, I think wraps everything together in a very nice way. With that being said, it seems to me that you have constructed your practice more or less based around that paradigm. From what I understand, your practice, it's a pretty unique setup, and so I would like to hear about beam radiology, and basically, where did the impetus come from to start what is essentially kind of a small boutique radiology group and what have been the challenges and the rewards from pursuing that?
[Dr. Olivier Clerk]
Yes, no, absolutely, it has been quite a ride so far, but we started from humble beginnings and now we have five locations, one outpatient surgical center that would probably qualify if we were located in the US as an ambulatory surgical center. We have a good portion of the practice that is doing teleradiology. We're covering 22 imaging centers, one Level 1 trauma hospital, and we have the full suite of radiology that we would expect in any hospital or center, so, 3T MRI, intraoperative CT scan. We have dynamic X-ray, 8 pain procedure room, OR, about 15 ultrasound rooms that are heavily running into MSK studies.
Yes, it has been quite a journey. We started small, but I think last time I checked, we were close to 100 employees.
[Dr. Jacob Fleming]
Wow.
[Dr. Olivier Clerk]
I think the initial interest here was really to build a practice that would allow us to proceed with those more advanced interventional techniques. I was very passionate about what I do, and I think it was missing to have a more comprehensive approach for patients that patients can rely on one single center or practitioner, or practice to be able to have an answer to their interrogation and concern and the treatment within the same facility as well because often, you can have, a great diagnostic practice that may find the area of pain of the patient, may find a fracture, may find a lesion, and then the patient will have to go to a different center for treatment.
The idea was to build something, a structure that would allow us to treat virtually everything. Currently, we have the provincial program for intrathecal pain pumps, we're doing spinal cord stimulator, lots of vertebral augmentation, including vertebroplasty, kyphoplasty, osseous augmentation, a spine jack. We're doing lots of disc augmentation, now with some clinical trials that we have, nucleolysis, lots of simple blocks, various types of ablation from spine, knees, hips, shoulders, lysis of adhesions. Even deep facial blocks or ablation that normally are done more in hospital, that we do very safely as an outpatient setting. We started very small, but now we have grown quite a bit over the last few years, and now we're really starting to have I think a very comprehensive pain practice.
[Dr. Jacob Fleming]
Wow, that's a really comprehensive setup, and I'm sure that many of our listeners are salivating at what you described in terms of the technology you have available and being able to bring that into predominantly outpatient-based practice. That is just really inspiring to hear. One thing I wanted to ask is how many physician partners are in your group currently.
[Dr. Olivier Clerk]
Currently we have approximately 10, I would say 3 to 4 that are more interventional lining. We have a portion that will be providing more diagnostic reports or will be reading remotely part of the teleradiology aspect of the practice. That is mainly in different health jurisdictions, but onsite doing more interventional work, we're about four.
(2) The Basis for Basivertebral Nerve Ablation (BVNA)
[Dr. Jacob Fleming]
Very nice. I think the advantages of that multifaceted approach are pretty obvious for anyone from the radiology background to understand the typical difficulties, which you alluded to in terms of we have the imaging technology, but going to the next level and being able to directly evaluate the patient and perform the procedure for them, it's a gap that can be difficult to fill. Very cool to hear about your success with that, and I'm sure amidst your practice, something that has been crucial to expand this, is the treatment of anterior column pain, and so I'd like to dive right in and talk about vertebrogenic pain. First of all, we'll just start with the elephant in the room. What the heck is the basivertebral nerve? What is it and why ablate it? Just tell us about it.
[Dr. Olivier Clerk]
Yes. It is definitively a nerve in the anatomical structure that gained lots of momentum and lots of interest in the last few years. I would say even 10 years ago, most of the radiologists or interventionalists did not even know about this structure that now is, in my opinion, essential for any type of pain practice. The basivertebral nerve is a non-myelinating nerve. That's one of the key points that differentiate this nerve from, let's say, the medial branch nerve or any other peripheral nerve that you may want to ablate that will regrow with time.
This one, once treated with thermal ablation, will not grow back. This has been very well described with ex vivo studies and also consolidated now with the SMART clinical trial that we have patients, that, the trial went up to five years, but we now have patients coming out at seven and eight years, that have actually virtually no pain still after treatment. That's a first really key point of this nerve. This nerve is located within the central portion of the vertebral body, so, midpoint from superior endplate to inferior endplate, and about a third ventral to the posterior wall of the vertebral body.
If you take a look on a sagittal T2 sequence, normally you see within the posterior aspects that at the midpoint of the vertebral body, you see a small triangle that starts from the posterior wall. That is called the basivertebral canal. This canal will contain a small nerve called the basivertebral nerve, an artery and a vein, and we can treat that nerve by ablation. This nerve will arborize toward the endplates and will bring all the pain afferents from under the endplates, the superior and the inferior endplates back to the central portion of the basivertebral canal where the nerve lies.
Then the neural afferents will go back to the brain. In a nutshell, the basivertebral nerve will be responsible for what we call vertebrogenic pain, so, pain arising from the vertebral body. There always is a question, how can you differentiate this pain from discogenic pain?
[Dr. Jacob Fleming]
Yes.
[Dr. Olivier Clerk]
It can be very challenging, and in my opinion, it's virtually impossible to differentiate both. The reason is, continuing with the pain and the neural afferent back to the brain, the basivertebral nerve will pass through the sinuvertebral nerve, and the sinuvertebral nerve is also responsible for the innervation of the disc. Because of that neural connection there, it's very difficult to differentiate both. To determine if the patient has more vertebrogenic pain, we will rely heavily on MRI. Obviously, first, a physical examination, the patient will have low back pain with flexion maneuvers, sitting.
Often sitting at 15 degrees that stress more basic for the anterior column. Will the patient have pain when he bend forward with weights, pain with vibration in car and in plane? All those that are typical for anterior column pain. That's one of the first thing that we'll see. Then after that, if the patient has evidence of endplates, Modic Type 1 or Type 2 changes, then the patient becomes amenable for a basivertebral ablation procedure. That's a little bit how we can select those patients. That's a little bit what we see. There's a big component that will be relying on physical examination and also on imaging for that specific treatment.
[Dr. Jacob Fleming]
Thank you for that wonderful overview of the pathophysiology and the workup for these patients. Just as a review for our listeners who are maybe a little bit more removed from diagnostic spine or neuroradiology, the Modic changes, like you mentioned, being the absolute hallmark of vertebrogenic pain. To review, the Modic Type 1 changes are the edematous changes of the endplate. That would be a bright on T2 weighted or obviously stir and dark on T1. Then the Modic Type 2 changes, fibrofatty endplate changes, which are bright on both T1 and T2 sequences.
I appreciate you mentioning the difficulty of differentiating discogenic and vertebrogenic pain and the sinuvertebral nerve specifically, that connection is quite interesting. I understand it's something that that overlap can actually be taken advantage of. One of the next things I wanted to talk about is you mentioned some of the things that make the BVN different from other nerves in terms of it's not myelinated, it's intraosseous. Because of the intraosseous location, there's not really a great specific diagnostic block in the same way that we would say, for example, medial branch RFA, where the injection, the diagnostic block of the medial branch is very analogous to the ablation procedure itself.
Due to just the anatomy, it's not amenable to that, but the overlap with the sinuvertebral nerve pathway is something that could be taken advantage of with the anesthetic discogram. I'm curious, is that something that you use in your approach as sort of a diagnostic block? If so, can you tell in what context you may use it, or are there times where you're just convinced that it is vertebrogenic pain and to proceed ahead with the ablation procedure?
[Dr. Olivier Clerk]
Yes, absolutely. This is a crucial procedure also within my practice. Yes, I do use a lot of diagnostic and therapeutic anesthetic discograms quite frequently to confirm that the pain is coming from this specific disc level or from endplates that seem to be degenerated or have Modic Type 1 or Type 2. Also, the Modic Type 1 changes will be very frequently painful, so that the edematous endplate, so, bright on T2, hypo-intense on T1, very, very highly related to pain. I think the last time I checked, about 75% of those patients, of those type of imaging changes will be correlated with pain, versus the Type 2, you have early changes, and you have later changes.
Later changes sometimes may be less painful. It is kind of worth it to really determine if the patient would benefit from a procedure, and determine and confirm also that this is really anterior column pain. It's not coming from a different level. It's not coming from facets or any other area that could also be a confounding factor in that aspect. Definitively, diagnostic and therapeutic, and mainly anesthetic discogram is essential. We're doing it on every patient. If the patient responded well, meaning that the pain will decrease from a 7, 8, 9 on the VAS scale, to a 0, 1, 2, 3, at least 50% to 70% pain decrease. Then you have also the hallmark of vertebrogenic pain, which is on the MRI, the Modic Type 1 and Type 2. In a skeletally immature patient, patient did not respond to conservative care for at least 6 months, then you can proceed with the ablation.
(3) Procedural Techniques & Considerations
[Dr. Jacob Fleming]
Excellent. Thank you so much for walking through that algorithm. I think it makes a lot of sense in the parallels to the typical diagnostic block and ablation sort of procedure that's common throughout interventional pain. That parallel is obvious, and again, the differentiating factor being the Modic Type 1 or Type 2 changes. We will talk a little bit later about how to approach patients who respond well to a discogram but do not have the vertebrogenic changes. Excellent. We've walked through patient selection, your whole process to that. 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]
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 [unintelligible 00:22:08] G stylet assembly that is surrounded by peak. This is a curve 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 spatial tip will create a channel in which you'll be able to push a bipolar ablation probe. The goal is really try to reach as much as possible to be at least 1 centimeter ventral to the posterior wall of the vertebral body.
This, 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 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 never 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]
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]
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]
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]
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]
Yes.
(4) Overcoming Common BVNA Challenges
[Dr. Jacob Fleming]
Excellent. 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]
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 though. 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]
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]
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]
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 case, 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.
(5) Post-Procedural Care & Long-Term Outcomes
[Dr. Jacob Fleming]
Very nice. 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]
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]
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]
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]
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.
(6) BVNA Integration into Daily Practice
[Dr. Jacob Fleming]
Such a crucial perspective with that that you bring up, talking about the treatment alternatives. This is what's so interesting about this pathology and the treatment, is that prior to a few years ago, really lumbar inner body fusion with posterior instrumentation typically would be one of the few things to offer to patients who had failed non-surgical management. The data on those approaches, as you said, they're, as you might expect, not exactly what I would call encouraging, in that a success for surgical treatment for stable discogenic or vertebrogenic back pain, success is about 30% reduction in pain.
You compare that to a potential for 75% or more in 75% of patients, it's a no-brainer. One thing that I think is so important about this is that the surgeons who, of course, have the fusion capabilities at their disposal, and, of course, those are used mostly for instability or deformity, these are not typically the patients who we are seeing with the vertebrogenic pain. These are typically, a lot of them are younger patients, most of them without spinal deformity. As you said crucially, that they are stable. The surgeons, I think one thing that I really do want to emphasize, is they definitely have the capability to use this technique too.
I've seen that as well, that a lot of orthopedic spine surgeons and neurosurgeons have started to employ this in their practice. I think that's great. I'm all for that. I'm all for all spine specialists having as wide an armamentarium at their disposal. It's certainly something that I feel that the experienced spine interventionist can bring to the table in a setup, whether that's a hospital or a group, or a community where this therapy isn't being used yet. It's a great way to get in. As you said, this is a very unmet need until really a few years ago. It's still being propagated, and it's a great place for spine interventionalists and definitely interventional radiologists to get involved. That's one thing I wanted to ask about you. Any advice for spine interventionalists and in particular from a radiology background to incorporate this into their practice?
[Dr. Olivier Clerk]
Yes. This is just like you outlined. This is a procedure that can be very easily implanted into any type of outpatient facility, to an ESC, to a hospital. The footprint is minimal. The amount of additional instruments is marginal. Basically, this is all if you're practicing in the US, you will likely be using the Relievant system, it’s all disposable tray, so it's very easy to start within your practice. Especially if you're already set up to proceed with vertebral augmentation, this is, in my opinion, a no-brainer, something that you should be adding to your practice.
That if you're able to do fairly basic physical examination of the lumbar region that is virtually asking if the patient have pain with flexion, maneuvers, pain with sitting, and you see Modic Type 1 or Type 2 change on the MRI, if the patient respond also to the anesthetic discogram, failed at conservative management for six months, you can proceed with this intervention. It's easy to learn and fairly easy also to add within your practice. I highly recommend adding this procedure to your skill set and your belt. I don't see this procedure going anywhere for the next couple of years.
[Dr. Jacob Fleming]
Beautiful. It's really a rare thing that such a relatively simple procedure is so effective and relatively easy to implement. Like you were saying, it's just a no-brainer, specifically, if you do have experience doing these transpedicular approaches, which anyone who's done a number of vertebral augmentation is already doing. I definitely hope to see increasing radiology usage of this. It's definitely gaining some momentum in the interventional pain community in the US, which, again, is great. I'm all for the propagation of these techniques and treatments, so we can take care of as many of these patients as possible and avoid the downsides of long-term failed conservative/non-surgical management or unnecessary, more aggressive approaches. I couldn't agree with you more on that.
[Dr. Olivier Clerk]
Often with those new emerging technologies, one of the limiting factors is that unless you're part of a clinical trial study, you can't proceed with this intervention with part of your practice before there's clear CPT codes. Right now, since actually, January of last year, the CPT codes are there, 64628, to proceed with a two-level vertebral BVN ablation. 64629, that's if you're adding another vertebral body. Basically, if you want to treat three vertebral bodies for two discs, the codes are there, added within the AMA, a new code for a vertebrogenic low back pain, so M 54.51. Everything is there, so it's very easy to implement and to get reimbursed also for those interventions.
[Dr. Jacob Fleming]
Amazing. Thank you so much for the billing tidbits there. Of course, they're more than tidbits because the devil is in the details. If we have an amazing procedure and can't get reimbursed for it, then it's dead on arrival. This has a lot of momentum, a lot of necessity in the community to employ this approach. It's practical at this current point in time. As you mentioned earlier, in different countries, things are going to be a little bit different. From my understanding, it's certainly gaining momentum, obviously, in Canada, the US, and in certain countries in Europe as well.
That's great. Hopefully, we'll continue to see this propagate worldwide because as we know, vertebrogenic pain knows no boundaries. These are common consequences of the biomechanics of being alive. It's just an excellent approach. That's really all I have as far as basivertebral nerve ablation. Do you have any final thoughts on that specific topic before we pivot?
[Dr. Olivier Clerk]
No, I really do think it's an essential procedure for pain practice. Yes, I invite everyone to get trained on it. If you're not already doing it within your practice, to start doing it, you'll save the lives of many patients and change their lives. Just like doing work also on the disc, I think working on vertebrogenic pain is essential. That right now, this procedure has the highest level of evidence, Level 1 evidence, for vertebrogenic pain, so it is an essential procedure for any pain practice.
(7) Future of Spinal Pain Management & Expectations Beyond BVNA
[Dr. Jacob Fleming]
With that excellent segue into the allusion to discogenic pain, I do want to talk about some of the even further bleeding edge techniques that you're working on. You mentioned earlier, disc augmentation. I want to talk to you about your work with that, with the disc hydrogel. You've been working on a clinical trial with this. Just tell us about what's involved with this. Where does this fall into the anterior column pain treatment option melange? Where are we right now? Where do we expect to see that go?
[Dr. Olivier Clerk]
Yes, absolutely. The way that we set up our practice is also to provide high-level and high-quality clinical trial. We're running quite a few of these. A good portion of the interest right now is on the anterior column because we all know that most of the low back pain is not facetogenic mediated, but rather 60% or even more is mediated by the disc, the vertebral body. Currently, until, we just talked about BVN ablation, but there's not other minimally invasive treatments that will reliably treat the region of pain.
To palliate to this, there has been, for multiple years, an attempt to inject a gel inside the disc, try to rehydrate, basically, those discs, and provide some support. There was in the year early 2000, a hydrogel called Gelifex that was tested, but they noted lots of expulsion of the material, and unfortunately, this did not go too far. That was the first generation of a hydrogel that was tested. Now, there's a second generation that is available that is made with PVA, PVP, and PEG. Basically, it is a gel that you need to heat prior to injecting.
You're heating at 65 degrees celsius, this gel becomes liquid, and you can inject it through a 17-gauge needle. You're using the classic Kambin triangle approach. You're making sure that the tip of the needle is centrally located within the disc, and then you inject that disc. So far we've treated, in my center, 35 patients. Overall, in the world, I think we're past the 100 patients. In North America, we're actually the only recruiting center right now, and the results are just good. They're phenomenal. The average pain decrease of patients with stable discogenic back pain that had one or two levels of disc generation, decreased their pain score from a 6.8 to a 0.9, which is to be permanent.
[Dr. Jacob Fleming]
Wow.
[Dr. Olivier Clerk]
We're continuing to follow those patients, but so far, the results at one year seems to be quite sustained with no significant adverse events that are device-related that we saw within my cohort. Really good results so far. Very exciting technology. It's interesting to see also where the gel lies. Sometimes the gel lies whenever there's less stress within the disc, which is often where you see either radial or circumferential annular tear. Sometimes the gel will migrate up to the borders of the disc, which initially can seems a little bit concerning.
This is purely part of the gel. It will just provide support where there is no support, and a follow-up of patients of now two years plus in the other center, the gel just lay there and should be good for actually about 40 years.
[Dr. Jacob Fleming]
Wow.
[Dr. Olivier Clerk]
Seems to be so far a very promising treatment. We're still getting data on this treatment, but so far, very, very promising and excellent patient satisfaction. I think 95% plus of patients would suggest this treatment to family members or other individuals that they know. Lots of the individuals that we treated were out of work because obviously if he got back pain, they went back actually to work.
[Dr. Jacob Fleming]
That's incredible. It really reminds me of what we were talking about with vertebrogenic pain, in general, is that prior to a few years ago, this was a problem we didn't really have a good mousetrap for. A lot of different things have been tried in the disc over the years, from things that are more a nuclear lytic, to things that are actually trying to augment. As you said, the augmentation approach just, it doesn't have anything good available for it, or really, anything outside of a clinical trial at this moment. That just sounds like a really exciting frontier.
As anyone who's read spine MRI for more than a day will know that the issues of disc degeneration and annular tears, and this whole spectrum is just incredibly common, and debilitating. Like you said, some of these patients can't work because of it. What are you going to do to use them or put in an intrathecal pain pump? Those are things that happen. It's not to throw shade on that, and certainly, depending on the individual situation and context, sometimes more aggressive things are necessary, but in general, the entire approach that you're working on, is it seems to be getting the absolutely most ultra minimally invasive way to deal with the given problem.
This sounds like just that for the specific category of discogenic pain. We definitely look forward to hearing more about that and certainly hope to have you back at some point in the future to give us an update on that and what we can hope to see in the future.
[Dr. Olivier Clerk]
Oh, absolutely. I have no doubts that we'll hear lots of new developments on the anterior column treatments, on the disc injectables. I think that that's one that it seems to be very promising, but there'll probably be others also that may be able to help with larger type annular tear, also that normally that we cannot inject gel in those annular gap or larger torn other annulus. That will probably be coming also at some point, but lots of new developments within that field. I think, at the end of the day, everything that we're doing is for the patient and to provide better outcomes and less time in the hospital, and faster recovery.
I think really, everything that is happening currently is spearheading in that direction. It's a very exciting field, and I definitively convinced that within the next couple of years, we'll have very good therapies for the anterior column.
[Dr. Jacob Fleming]
Agreed completely. That's just really exciting. Speaking of new developments and frontiers and spine interventions, are there any other particular developments that you're excited about outside of the disc and the disc augmentation, and basivertebral nerve ablation? Any other particular things on the horizon that you're really excited to see where it goes in the next few years?
[Dr. Olivier Clerk]
Yes, absolutely. The only thing that we didn't talk and maybe that's going to be a topic for another podcast, but all those patients that have single or dual-level registered symptoms, secondary to a herniated disc, what do you do with those patients? Basically, there's more and more treatments that are minimally invasive, allowed to resorb or mechanically extract, physically, this herniated disc. One of them that we're working currently is with, we're performing nuclear lysis. Basically, you can inject a gas, ozone gas that basically will shrink a small portion of the nucleus pulposus right behind the herniated fragments, and will resorb the disc protrusion.
I did five or six cases right before Christmas, and all of those patient, they're all doing amazing. They have either significant decrease in their registered symptoms or completely gone. I have even followed on a firefighter that was completely out of work, had a herniated disc. I imaged the patient before the procedure, and after the procedure, and it looks like there's no neural impingements. The herniated fragment is completely resorbed. Quite remarkable for a procedure that you can do in such a short amount of time as well.
[Dr. Jacob Fleming]
Fantastic. Yes, I have to agree. I think that minimally invasive treatments for HNP as we call it for short, herniation of the nucleus pulposus, is another one of these omnipresent problems that plagues adult patients. There are a lot of exciting things coming out on there. We'll definitely need to have a specific discussion of nuclear lysis techniques and of course, one of my particular interests is the endoscopic spine surgical approaches, which are obviously gaining a lot of traction among the surgical community. I think that's another area that is absolutely the frontier. As we go further into that era, there's going to be no turning back, which, in the best way possible to making treatments for these debilitating conditions as ultra-minimally invasive as possible. Really exciting to see what comes out in the next few years.
[Dr. Olivier Clerk]
Absolutely.
[Dr. Jacob Fleming]
Olivier, it's been great talking to you. I want to thank you so much for your time sharing all your wisdom and experience with a basivertebral nerve ablation and talking about other anterior column treatments that are coming out. With that being said, I have nothing else. The floor is yours if you'd like to promote anything you're working on or have any final thoughts before we close.
[Dr. Olivier Clerk]
No, I think we covered the topic very well there. I would like to thank you for the invitation. This is quite a fantastic podcast that an interventionalist can go share their experience and enthusiasm, and new techniques, and ideas with the community. Thank you for hosting this podcast and continue doing the great work that you're doing and happy to come back if there's any other topic of interest. Otherwise, until next time.
[Dr. Jacob Fleming]
No question, we'd definitely like to have you back. I think we've outlined multiple potential topics for the future. With that in mind for our listeners, thanks for tuning in, and catch you next time.
[Dr. Olivier Clerk]
Thank you. Bye-bye.
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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