BackTable / MSK / Podcast / Transcript #33

Podcast Transcript: New Frontiers in Spinal Tumor Ablation & Augmentation

with Dr. Dana Dunleavy

In this episode, host Dr. Jacob Fleming interviews Dr. Dana Dunleavy about spinal tumor ablation and vertebral augmentation. Dana is an interventional radiologist and Director of Windsong Interventional & Vascular Services. You can read the full transcript below and listen to this episode here on BackTable.com.

(1) Recent Advancements in Spinal Tumor Ablation

(2) A Comprehensive Approach to Tumor Ablation & Vertebral Augmentation

(3) Procedure Insights & Common Challenges

(4) Choosing Between Transpedicular & Extrapedicular Approaches

(5) Balancing New Imaging Technology & Tactile Skills

(6) Interventional Radiology’s Expanding Role in Cancer Pain Management

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[Dr. Jacob Fleming]
Now, back to the show. This is your host, Jacob Fleming, and today, it's a pleasure to have on the show Dr. Dana Dunleavy, interventional radiologist, and it's not your first time on the show. Most recently, you did an excellent interview with Wayne Olan, so I want to officially welcome you to The BackTable team and welcome you as my guest tonight. Thanks for your time, Dana.

[Dr. Dana Dunleavy]
Thank you, Jacob. A great honor to be here.

[Dr. Jacob Fleming]
It's a lot of fun to have you and talk about these topics. I know we both share a lot of passion about. You've devoted your career toward pushing forward interventional spine, particularly in the oncologic area, and that's really our focus for today. We're going to talk about bone tumor ablation and as well how to incorporate vertebral augmentation techniques from vertebroplasty to mechanical augmentation, such as with the SpineJack device. This is an area where there's a lot of growth. We're seeing evolution almost constantly in terms of the techniques that are available. Before we dive in, just tell our guests or our listeners a little bit about your background and training.

[Dr. Dana Dunleavy]
Thank you. One of the things that sometimes comes up is just how odd I am. Growing up in a small country town, my mom was a midwife and continues to be a midwife and my dad a contractor and had a nice balance of being involved in healthcare and also getting some of that hands-on experience. I also had opportunities in this hippie town to work on a biodynamic farm, drive tractors, do a lot of gardening, and really allowed me to come to a good place in where I should be in medicine.

Combination, again, of growing up, delivering babies in our house, in other mothers' houses, and then, realizing through my athletic career that I wanted to do something in the musculoskeletal system. I went to something called a Waldorf school, where they focus on things like movement, music, and language before you get into other things like mathematics and science. Then in high school, I went to SKI Academy. The joke is we didn't learn a whole lot, but we did develop and learn how to succeed in anything we did.

After that, I went to college at Middlebury and was on the Division 1 SKI Team where that's when education began. I think that's the opportunity for all these people who take a different path is really finding their passion and understanding how to succeed. After that, ended up at Johns Hopkins for both residency and fellowship. I guess I should just take one step back in that. Many people in this area, like yourself and like myself and Tony Brown and Jack Jennings and Doug Beall and many others, really had a tough time deciding between orthopedics, neurosurgery, and interventional radiology.

I think that we've all found our perfect place in really not only combining those fields but working very collaboratively with those specialists. I was unofficially accepted into orthopedic residency as a medical student before applications began. In spending a lot of time doing acting internships with orthopedics and radiology, found some amazing mentors and really that pulled me into interventional radiology.

[Dr. Jacob Fleming]
Fantastic. You alluded to in your prior discussion with Dr. Olan, you did seek some training outside of your formal residency and fellowship training in order to focus into the spine. Tell us, how have you gone about that? Then leading into the next question about your current practice, specifically the vertebral augmentation and tumor ablation practice, how you got to there, knowing that it took a lot of extracurricular effort, given the lack of this stuff has been unfolding over the course of your career. The formal training pathway is still not yet defined for this weird hybrid that we strive to do.

[Dr. Dana Dunleavy]
Very true. when I was a medical student and I was accepted into Johns Hopkins, basically everyone said, "You have to go there." It was based on, this is the Number 1 institution in the country and arguably in the world. What an amazing experience it was doing a lot of interventional oncology and seeing people that travel from all over the world for complex things you normally wouldn't see at all in your career. However, to your point, the musculoskeletal aspect, doing vertebral augmentation or other areas of interventional pain treatments, I felt wasn't adequate for what I wanted.

The program was very supportive of allowing me to do some externships, so to speak. Wayne Olan was only an hour away and essentially that's all he did was interventional spine all day, every day. I immersed myself in it for a month and it was incredible, coming back and sharing that experience, giving talks to my co-residents and co-fellows. I wasn't the only one. There were other residents and fellows that left Hopkins and did similar things, including the program you're at now, coming back and saying, "Hey, this is the future of what we need to be doing," and that was true.

In the process, I think I've also participated with all of our colleagues across the country to say that there is a role for how you can continue training after fellowship. That might be with your colleagues in your same group, but you've seen, right, that many people either are in a small group, they may be switching to an OBL or an ASC. They may have been in a program that was like mine, really intricate and amazing on the interventional oncology side or the peripheral arterial disease side, but maybe not in this area.

I think that there's a lot of opportunity both to network the way that we are here, with BackTable through, the different pain councils, I shouldn't say just pain councils, but the CSCs. We now have different focused councils within the Society of Interventional Radiology. I work particularly in the pain council, but there are other councils that are very helpful and then, working with industry and with our colleagues. I think that is one opportunity we have to continue education. I just had one of my peers out in Bozeman say, he's on Year 26 of medical school and all he meant is continuing education always.

I've really enjoyed the opportunity I've had to teach, both interventional radiologists, interventional pain, PM&R, neurosurgery, orthopedics. As Wayne mentioned in our last episode, I find that I learn even more than they do each of these opportunities.

(1) Recent Advancements in Spinal Tumor Ablation

[Dr. Jacob Fleming]
Yes. The cross-pollination I think is really great. As you know, that's what we're all about on BackTable is collaboration over competition and learning from each other to push forward what we can offer to the patients. Of course, our focus today being on the oncology patient and specifically bone metastasis, essentially spine metastasis. This is just a very intense focus for a lot of our colleagues and something where I'm really excited about what's come out in really just the last year. Tell us a little bit about your practice. How does the bone tumor ablation fit into that as well as vertebral augmentation? What's been your opinion of what's been unfolding in the last couple of years?

[Dr. Dana Dunleavy]
Sure. Again, with different mentors, including Sean Tutton, who I had the opportunity to work with a couple of days ago, really had tremendous amount of opportunity to learn from these guys who are really pioneers. I feel like now you and I are benefiting a lot from that and really taking the opportunity to improve quality and access to care across the country. I think that there are still tremendous opportunities we have to share with our colleagues, how simple, safe, efficacious, radiofrequency ablation is of bone metastases and knowing all the different modalities.

I think that we come out of training, for instance, really understanding what do you do with liver disease. Then you come out and you say, "Well, how do I grow my practice in interventional oncology focused on the spine?" There seems to be this big gap. The number one most helpful thing is being a helpful part of the team and by doing that, providing great quality biopsies. If we are capable of being present at tumor board, again, that's not just academic centers, it's private groups, that's office space settings. I mentioned a lot that COVID, one positive was that almost every tumor board is available remotely now.

Even a small-town office space guy like me participates in several tumor boards from multiple networks every week and always, people are bringing up, "Hey, there's this T5 little thing that lights up on PET. Patient had breast cancer five years ago. I wish there was some way we could figure out what this is." It's always short. That's really simple, really easy. If we can be a helpful part of the team, make the diagnosis, we also have that same ability to treat it. I think then the question is, can you do it safely?

To your point about all of the increasing data, I thought one of the interesting studies that a lot of our colleagues haven't read is one of the publications by Jack Jennings, where he showed cryoablation, microwave ablation, and radiofrequency ablation and intentionally, in this model made ablation zones that were far too large. The nice thing about that was to showed that even using those inappropriate temperatures and times still maintained a safe ablation within the spine because of that impedance in the cortex, but resulted in neuropathy and paralysis using cryoablation and microwave ablation.

It's just helpful for us to really understand how this can vary safely and quickly be performed if you understand each of the technologies. To your point again, about some of the developments in technology, I think it's good for us to have access and hands-on to all the devices. There's no reason that anyone should be locked into a single device. For instance, if we just go through radiofrequency ablation, Merits had a wonderful device, Medtronics had a wonderful device, Strykers had a wonderful device. All of them are really great in the right hands and the right experience and each of them have their different advantages.

It's interesting, right, that you go to different regions and people think that there is only one device and they've never heard of the others. I just think it's very important that we share with each other all of the different techniques you have. To just go back to what you're asking, I think the data continues to grow.

Unfortunately, many of our trials are very small and I think still when I present with radiation oncology, they will always win if we fall back on who has better data, who has more data. If we look at their trials with 20,000 patients in our trials with 200, it's a little challenging. It's the same challenge we have with PAE. We say TURP versus PAE, I think we have wonderful data, but it's still not as in-depth that TURP is. Do you want to move on to some of the mechanical augmentation too?

(2) A Comprehensive Approach to Tumor Ablation & Vertebral Augmentation

[Dr. Jacob Fleming]
Yes. Absolutely. The next question that I'd like to talk about is, you mentioned the tumor boards and how these referrals will come to you, really can't overstate the importance of that approach because I talked with Majid Khan about this recently in our discussion that the days of being just sent to patient do this, it's over. [chuckles] I would say for better or worse, but I think that's definitely for better. You have to be involved from the very beginning with the biopsy and the diagnosis.

Say you have a patient who comes up in tumor board and you feel can really benefit from what you can do in the interventional spine area. Tell us about pre-op imaging and what kind of considerations you're having with patient selection when we're talking about bone tumor ablation. Then to your point, about mechanical augmentation, when does that come in?

[Dr. Dana Dunleavy]
Great. Just to start off, Majid Khan is an amazing pioneer as well and I've learned a tremendous amount from him. One of the ways you learn that you're impactful is when you move away from an institution and they force you to come back. That's been great for him. I love the type of research he does because he questions everything. Even our really great outcomes and great publications, he questions. I think we're looking at some of that to make sure that everything is what we think it is and that we're doing the best we can. As one of the recent BackTables, we discussed that we all went into medicine to relieve suffering so we want to make sure we're doing the best.

In terms of the pre-op imaging, I think this goes back even to doing good biopsies. When we are participating in those biopsies, I always do a consult with those. It doesn't have to be that it takes all day, but it's the fact that we met the patient and we discussed why we're doing this biopsy, the risks and benefits of it, and why are we doing it because this might be a neoplasm. If it is, what do we do next steps? In that process, every single patient, when they go back to their oncologist and discuss that this is a metastatic breast lesion, prostate lesion, myeloma, plasmacytoma, they always ask to come back and have that simple treatment where it was like a biopsy but they put a probe in it and they made it go away.

I think number one is just doing a simple face-to-face contact and the imaging part. Maybe we get into NCCN guidelines a little bit. I think it's very important for us to know that MRI is the gold standard for looking at metastatic lesions of the spine. Oftentimes, people think it's PET. PET is the way to go if you are an oncologist and you're looking to stage, but it's not as sensitive for looking at the spine. Then you obviously have the high resolution of CT. If we look at some institutions, they do all three of those.

I'll just tell you my personal opinion is, if it's convincing enough on any, well, I shouldn't say on CT alone, but on MRI or on PET, then we will go ahead and treat because we do know that patients do much better with early intervention and especially with these posterior vertebral body lesions that are at the pedicle body junction or close to the basal vertebral nerve and plexus. Those lesions are soon in the epidural space and we're talking about changes in Bilsky score so we try to intervene immediately if we know we need to.

However, say the patient is referred to me with a PET scan, they ask me to do a T12 ablation, we will still get an MRI, but it will be after our treatment. Part of the reason for that is because we know that we're missing some of the lesions on PET and we may also be missing some other aspects, some pedicle involvement.

However, nothing is going to change for that vertebral body that we were referred. We are not going to make people go through a checklist of 12 things while they continue to get worse because we certainly see that frequently that patients that have a delay in intervention end up in the hospital either with pneumonia, DVT, PE, constipation, anorexia, a bunch of issues that just seem so simple but similar to vertebral augmentation data with osteoporotic fractures, but much worse in the malignant category.

[Dr. Jacob Fleming]
Absolutely. At the risk of asking a question that seems simple or obvious maybe, there are some people who treat spinal metastasis with a pathologic fracture with vertebroplasty alone. It's something that's been done and is done to this day. Talk about the rationale for bone tumor ablation prior to augmentation.

[Dr. Dana Dunleavy]
Sure. To keep it as simple as possible, I think that the way that Tony Brown, who's described this really well says is if you have an osteoporotic or a traumatic fracture, we're talking about mechanical pain and that does very well with Vertebroplasty or kyphoplasty, and we can stabilize that instability and patients do very well. When we think about malignant lesions, we're talking about several different types of pain. We're talking about stretching of the cortex. One of the things that you often see on a spine MRI, the first thing that jumps out is this posterior bulging. You see the posterior wall just bulging into the spinal canal and that has a stretching type of pain.

Then you have the lytic aspects where you're destroying the nerve and the bony trabecular. Then you have also the involvement of either the exiting nerves or the traversing nerves and so you have multiple sources of pain that are not cured or fixed with mechanical stability. Again, just keeping it as simple as possible, mechanical instability works well with vertebral augmentation, but patients will certainly still have pain if you just do vertebral augmentation alone for these malignant lesions. I think that that gets us to something that people oftentimes-- the real underlying reason that people will defend why they do vertebroplasty alone.

The reason is that if they're old enough and they haven't used these newer technologies, doing ablation takes a really long time and they've probably seen some bad outcomes from that. We do know that if you're on the table prone and sedated for hours, very likely to have some post-procedure shoulder pain, pneumonia, various other issues that may develop, but as these technologies have continued to get better, ablation doesn't take that long.

I don't describe that as a dramatic benefit because we're going to make more money or because we can turn over patients or rooms faster. It's because it's safer and that it's very hard to find a reason that you shouldn't be doing radiofrequency ablation as part of your vertebral augmentation for patients with pathologic fractures because it's so safe and efficacious now.

[Dr. Jacob Fleming]
Absolutely agree. Just since you referred to it, what is the burn time like nowadays for most of these lesions?

[Dr. Dana Dunleavy]
If we look at one of the devices that people are oftentimes using, you're talking about nine minutes as the most common ablation time, and that ablation is designed to treat the entire vertebral body. I think that eventually will get us into a different discussion of do we need to treat the entire vertebral body. I think that on the one hand, people would say yes because we know that we safely can, and it doesn't take that long.

However, I would say that you are smarter than that. If you go into a kidney or a lung or a liver, you wouldn't just max out based on some algorithm that has nothing to do with the tumor size. You'd actually think about it and use a lesion guide or a cookbook or whichever term you want to use. I still think that that's appropriate. Let's be at least slightly intellectual enough to think about what the pre-procedure imaging looks like and plan our ablation. Some of these devices have measuring drills, they'll tell you which probe you should use, tell you which ablation time you should use, but I hope that we're all capable of looking at the PET or the MRI and knowing that in advance.

(3) Procedure Insights & Common Challenges

[Dr. Jacob Fleming]
Absolutely. That brings to mind an additional consideration is that all vertebral bodies are not the same, especially in the case of oncology patients, we often see very collapsed vertebrae with these pathologic fractures, extreme osteolysis just really changing the anatomy and the volume. Would stand to reason that the volume that you need to treat is probably different because we don't necessarily want to be ablating the adjacent discs if we can avoid it.

One of these situations that I think I'm most excited about is that prior to a few years ago in the US at least, we didn't really have good options for these patients who had a lytic tumor with a pathologic fracture or not necessarily even lytic tumor but just a pathologic fracture with a lot of height loss. To my knowledge, the only solution in that context that's available for us right now is the SpineJack, a mechanical augmentation device for restoring height.

I think it was about within the last year maybe that the SpineJack actually got FDA approval in addition to its prior indications of osteoporotic and traumatic compression fractures, but specifically 510(k) approval for the indication of pathologic neoplastic fractures. Using a bone tumor ablation system for the reasons you said, taking care of those different elements of pain, and, of course, the local control of the tumor is a major concern, especially for patients with oligometastatic disease. Up until recently, at least in the US, like I said, we didn't really have a good option for vertebral body reconstruction, so to speak.

I've seen some extremely impressive work from you, from others. I saw a case from Chicago, the other day that was just immaculately recreated the vertebral body with probably 80% to 90% of its original height from a practically a plana configuration. The stuff that we can do now is a lot more advanced than it was a few years ago. Tell us about integrating the two techniques of bone tumor ablation and mechanical augmentation. Where does it fit in? Certainly, mechanical augmentation is not something that needs to be done on every patient and has economic costs associated with it. Just tell us about how those two technologies come together for you. What are those situations?

[Dr. Dana Dunleavy]
Just to start off with the first thing you mentioned in terms of we don't want to ablate things we shouldn't. I think there's been some great work in the Southeast by Jason Levy, Dave Prologo, Neil Resnick, and some of their studies showing even more complicated things than the spine. Treating these lytic metastases and the acetabulum, a bunch of different interesting techniques for that, but also showing you the risk. For instance, if you do cryoablation in that area and you're not careful about what your ablation zone is, that will go right across the hip and you can induce a fracture of the femoral head. It is important that we know our anatomy and that we understand our technologies.

Again, I think that we should all appreciate the great data and publications that some of these guys are really spending a lot of time on because I was once told, "Hey, Dana, you need to make mistakes because that's the only way to learn." I said, "I don't accept that. I will learn from the mistakes other people have made and I won't make them." I think we have the opportunity to do that because of these really courageous people that have shown what happens with their own experience early on.

To get to your point of really severe pathologic lesions with oligometastatic disease, one of the biggest concerns we have is semantic extravasation. What better way to address it than by putting a construct in? Oftentimes, the calls that I receive are, "I don't think I can treat this patient. I really want to. Neurosurgery is asking me for help, radiation oncology is asking me for help but look at this lesion. It's a huge, lytic metastasis extends through the pedicle body junction, and I just don't want to harm the patient." I think that that's a good start is that we want to make sure we're providing a great benefit and very minimal risk.

One ways we can do that, again, is by putting an implant in. Tony Brown has done some amazing cases like this and one of the phrases he's used as a jack corpectomy. You're putting a SpineJack in and you're honestly recreating a new vertebral body from something that's just a plana of mud. There's really no recognizable bony trabecular anymore. The interesting thing with that is, for many of us that reach out to our neurosurgical colleagues or orthopedic spine colleagues and say, "Hey, this is a Bilsky. Let's go with 1B and do you want to treat this surgically, do a decompression, do a corpectomy, put a cage in here?"

The answer is almost always no. They know that the morbidity is so high with doing those procedures that if we can provide any benefit of symptomatic pain relief, reduced opioid use, increased mobility, functional improvement, and debulking of the tumor, then they want us to help. The way that I think we can succeed there is by going in ablating as much as we can safely. I don't think that that means you need to be unsafe and ablate into the spinal canal as an example, but then putting a structure in. We often times use this analogy.

If you're going to build a skyscraper, you wouldn't just take your cement truck and start shooting cement into the dirt and hope that that's a great structure. You would have slabs, and you would have rebar, and you would make sure that it's exactly in the form that you want. One of the great things about mechanical augmentation combined with ablation is that you're providing a structure after you do the tumor ablation.

Again, I think the bone biopsy, if we say doing a bone biopsy is easy, and I think that we all can do that, and we could spend some time on some different techniques to make sure we get better sensitivity and specificity, but if we can do that, then we also can do radiofrequency ablation. The challenging part is making sure that we provide the cement deposition in a location that is safe and efficacious and putting it through a construct makes it easy. That's, I think, the benefit. Right now, we're at a place where we can do ablation faster and we can also do the cement portion safer.

One of the things that I show people is that if you really want to minimize your cement, you feel really uncomfortable about it, you can put about a CC of cement into each SpineJack construct on each side in general, depends obviously what the vertebral body and what the size of the SpineJack and things like that looks like. Before, in most cases, it's going to extend out of that construct into your fracture cleft, and so if you're a true minimalist, you may decide that "I'm at least going to fill these two vertical columns of strength and help them more than I would if I did nothing."

Now, obviously, in the program you're in, that's not enough. You're then going to say, "I know based on the data from Europe that the single most important thing I can do for better outcomes is to increase the cement that I put in." If you're going to do that right, then you can still visualize that. You can go side by side, you can use curved needles. There's a bunch of different techniques you can use to put cement into the more intact portion of the vertebral body or various other techniques to make sure you can safely do that. Certainly, using mechanical augmentation makes it safer and easier, and I think that gets us a little bit into why would anyone not do that.

One would be that you think that it takes a long time, and so sometimes I just spend a little bit of demonstration with people to show, you access one side, put the probe in. As that's going, you then put your second cannula down, start that probe. First one finishes, you pull the probe out, K-wire goes down, Jack goes in, and then the second probe finishes, Jack goes in. Now, the most challenging part of the case, which was the cement becomes a lot safer and you really didn't spend any more time because, in the end, the hardest part becomes simple. That's, to me, the most important part.

Again, I think you talk to Wayne Olan, you say the myeloma cases, even if he's not going to ablate, which he usually doesn't. He and I and many others would say the plasmacytomas are the ones that we will ablate, but a general run-of-the-mill myeloma will just do vertebral augmentation. Using mechanical augmentation provides a lot of safety because many of those myeloma cases have some cortical destruction. You can't always see it because they're small, but they're very high risk for extravasation, and so doing anything you can to improve your cement containment is great.

The last thing I'll say going back to Majid Khan, is working on some other techniques for malignant fractures and how to best treat them as well.

(4) Choosing Between Transpedicular & Extrapedicular Approaches

[Dr. Jacob Fleming]
Excellent, and thank you so much for walking down how the procedure would go in terms of the sequential burns and placing the SpineJacks. One question that I had came up, took this for granted in our conversation that the prototypical approach is a bilateral transpedicular approach, a run-of-the-mill vertebral augmentation approach. Of course, in the last few years, well, more than the last few years there's been work done by Doug Beall, specifically about alternate approaches, parapedicular and extrapedicular approaches, starting to see these come out more in the interventional radiology community, which is great.

I've seen, not necessarily an oncology case, but a parapedicular unilateral SpineJack placed which can be placed in the middle of the vertebral body. That's great for very frail patients and patients who you're trying to make the procedure as rapid as possible while still giving them that civil engineering of the spine correction that you're there to do. I'm wondering for any of the oncology cases, would you ever stray away from the bilateral transpedicular approach? For example, a focal lesion or maybe a focal plasmacytoma, would you ever stray away from that prototypical approach?

[Dr. Dana Dunleavy]
Sure, great question. You gave a lot of very helpful information even in that question, so that was great. I think the best thing to overall take from that is transpedicular approach overall is the safest approach. For most interventional radiologists, interventional pain, PM&R, doing a transpedicular approach routinely is the way to go. I also think that you can do almost anything from a transpedicular approach now with the devices that we have.

If we think about some of our mentors that you mentioned, they didn't have these devices and so some of those approaches were necessary in order to achieve what they were able to achieve with straight systems, and with slow systems and things like that. I think it's very important to know the difference of transpedicular, parapedicular extrapedicular and why you might use each of those. I think it's also helpful to know that our first choice should be transpedicular. I also think that with mechanical augmentation, our first choice should be bipedicular.

No matter what, I don't think there's any orthopedist who focuses their career on biomechanics that would say that a unipedicular SpineJack is as good as a bipedicular SpineJack. I mean you just have so much more opportunity for better distribution of force. We think about the approach, again, using a transpedicular approach where those skis are ending anteriorly almost at midline, and as they come back, they're going lateral and so with two sets of implants, you're really almost treating the entirety of the vertebral body with that surface area.

Whereas unipedicular, if you were to do a Cone Beam CT at the end as an example, you'd see you really didn't have as much ability to expand the jack and cause and plate height restoration as you did otherwise. The other parts with that, there are certainly some examples where some of our colleagues do extrapedicular access and sometimes particularly with malignant lesions.

Some of the reasons for that would be that they might want to place an implant that is too big for that pedicle and the way to achieve the appropriate location within the vertebral body with the pedicle that's too small for as an example a 5.8 SpineJack, but you're putting it in a T8 vertebral body with a steep, narrow angulated pedicle is to start with an extrapedicular approach. There are certainly people that are doing it very effectively with the concept of, "We have a huge lytic metastasis here and we need the most surface area we can."

Something to think about on either severe avascular necrosis or a lytic lesion is that when you put your SpineJack in, it's floating there. It's not stable until you're able to get good opposition of the superior and inferior skis, and obviously if you have a longer surface area, you will reach that opposition sooner and safer. There is some benefits to that, and in fairness, too, large implants have more force. We talk about 500, 750, 1,000 newtons, and so sometimes if you're treating something that you believe needs more surface area and more force to create the best outcomes than sometimes you are finding another reason why you might choose an extrapedicular approach.

One of the things that people ask me, which is very simple, but I think helpful to know is how do you safely even do a high thoracic vertebral augmentation? I think this goes to that concept too. One technique that some people use is to just make sure they safely go down on the pedicle. They feel the pedicle and then they can actually take the interventional radiologist out of them and become a surgeon and just use tactile feel to walk their way lateral until they're walking their way off the side or lateral aspect of the pedicle and thereby know where they need to begin.

Now, you don't want any of these cases that we've heard of where people miss the vertebral body and either cause a huge hematoma or a pneumothorax. Sadly, those cases do exist, and so I think that you can very safely have the appropriate access just by using tactile feel.

[Dr. Jacob Fleming]
Absolutely. That's something that I've found I've been learning a lot about in the last few months, just doing a lot of vertebral augmentation cases and seeing a lot of thoracic cases, mostly in osteoporotic patients. The approach really is quite different from the lumbar, and the difference becomes more pronounced as you go further up the thoracic spine. The challenge is definitely there and I found that having to develop more of my tactile sense about realizing initially we aim for relatively close to the spine, obviously, to avoid a pneumothorax, but at the cost of transverse, cost of a vertebral junction, where that's all coming together.

Starting at the rib and knowing that you're safe and you're on bone, you know that you're not going to cause a pneumothorax, and walking towards that has been really helpful. The tactile sense, I really like what you said about taking the interventional radiologist out of it and channeling the inner surgeon. Actually, I really agree with that, and it does take me back to my general surgery days in internship where we're not doing things as precisely and image-guided as we are with most of our procedures. Actually, the resolution that you get from tactile sense in some ways is better than what you're seeing. That's definitely the case in these ones where anatomy is distorted, which is a lot of oncology cases. Sometimes you have to, this may sound like sacrilege for podcasts with a lot of IR listeners, but you got to turn that off for a second.

[Dr. Dana Dunleavy]
For instance, I don't know if the biking analogy works for people, but if you go to Wayne's world, and she's waving, "Hi Wayne," and you tend to steer away, if you turn your head, you don't tend to go straight. The same is true when I watch people do mechanical augmentation. If they're completely obsessed with looking at the monitor, even though they think they have a vertical orientation of the implant, they don't because their handle is moving while they're looking at the monitor. I think it's really helpful sometimes to just focus on the carpentry that you're doing and the artwork that you're doing and not always be looking away somewhere. There's quite a few other examples we have with that like say perforator ablation where sometimes you have to help people to not always look at the ultrasound, just look at the probe, and start to understand that you're nowhere near in the right place so stop looking up there. Exactly.

[Dr. Jacob Fleming]
That was something that I really experienced, just to go on a quick tangent, but something I wanted to share. When I was in residency, I learned vertebral augmentation strictly by the en face oblique approach in the lumbar spine. When I started fellowship, I was forced to very quickly acclimate to doing it on a straight AP approach, which I didn't have a whole lot of experience doing. There is a lot of frustration when first learning that approach where you're like, "Why am I not going where I'm going?" Multiple people that I've worked with have just been very helpful in this.

One of the best pieces of advice I got is look down at your hands. Look down at your hands and where you are on the patient's body and is your angle too steep? Are you too far off the midline? And forcing yourself to do that. Then of course, it's just like, well, duh, but I had to do the same thing when I was learning ultrasound-guided procedures before it becomes more of an intuitive kind of thing with the hand-eye coordination. Why is my needle not in plain? Why is it? Look down at your hands. [chuckles] Often the the answer is there. [chuckles]

[Dr. Dana Dunleavy]
Absolutely.

(5) Balancing New Imaging Technology & Tactile Skills

[Dr. Jacob Fleming]
That's one of our challenges as image-guided surgeons, so to speak, is that we're so facile with the image guidance that a lot of times just doing things as simple as possible and knowing that you don't in certain instances need to be having your eyes glued to the fluoro monitor. That gets tricky too when we're talking about ONC cases, and sorry to beat the drum on this, but where the anatomy is just really distorted and there's often not a lot of good landmarks to go by.

Would you speak quickly about your thoughts about using advanced systems such as Cone-beam CT with needle guidance navigation? Your experience using that, how you think it fits in, and is it something that we should all be doing? Sorry to make this a multi-part question, but the danger of becoming reliant on these advanced techniques, your thoughts?

[Dr. Dana Dunleavy]
I can see you're speaking from multiple mentors at the same time. I love that because that is helpful for us to address why this is a emotional question. My feeling is that there is a benefit to having that technology. Now, I was just talking with some neurosurgeons yesterday, and within this big group they have guys that use navigation every day and guys that never do. The older guys that grew up without navigation existing say this is a handicap of the young guys that they're reliant on it just as you said.

However, I think it's really helpful to utilize it and then understand that anatomy and be able to pick and choose when you think it's appropriate or not. Certainly, it doesn't add something in every case. As an example, I think that as we have discussions about things like sacroiliac joint dysfunction and pain and we read some of the literature that says that 40% of implants for sacroiliac joint fusion are in the wrong place, we say, wow maybe there is a benefit to having CT guidance or Cone Beam CT or trajectory planning or navigation because that's just not right.

Right now we do know that some people with C-Arms don't ever have a complication. It certainly is not necessary in all cases, but as an example, most of us are all trained to do most biopsies, especially bone biopsies and CT. I'll tell you that my belief is the hybrid is the best. That doing bone biopsies with a C-Arm alone is quite challenging to know that you truly targeted it and promise to your medical oncologist or radiation oncologist that what you get, a benign biopsy, that it's not a false negative.

My technique is to do the access under fluoroscopy and that a Cone Beam CT, which proves my device is going right through the lesion. I find that's good for me, good for the patient, good for the nurses. It makes all of these procedures really easy. The hardest part for the patient right, is lying in these uncomfortable positions. I think that that's a wonderful hybrid. The same is true for all of my bone tumor ablation cases. That I will access with the knowledge of what the anatomy is and where the lesion is under fluoroscopic guidance. Then I'll use Cone Beam as confirmation.

Now, some people take the next step, and patient walks into the room, gets on the table, they do Cone Beam CT and then they use guidance software that has a different name for each device, each system that we have. For mine, it's called trajectory planning. It means that for anyone that's never used it, you can scroll through your axial images as an example, pick your target, pick your access, you can have multiple different planes that you're using, so you don't have to access at the same craniocaudal plane.

To me, there's a big advantage of using trajectory planning over CT fluoroscopic guidance where having a very coddle angulation through a T-5 pedicle, much easier to do in an angio room or a fluoroscopy room than it is in CT. I've seen some of my friends under a CT fluoroscopic guidance where they're accessing from the wrong side of the CT scanner because of that angulation, you just can't reach through the entire scanner. Remember that most of our high thoracics, the cannula handle is almost in the patient's hair. That's the right way to do it. If you're not doing it that way, you'll probably have some post-procedure paraesthesia because you're too close to the neural foramen.

That's what I think is the ideal is having a combination for the difficult lesions. To some degree, I use that information for education and teaching so that people can take that combination of fluoroscopic Cone Beam CT trajectory planning views and utilize it on a C-Arm because they can put that all in their mind but that's the balance I think.

Now, I'll tell you this morning as an example, I was doing an ablation of the ileum and it was a really tall patient, the room we're in, it's challenging to do Cone Beam CT when his arms and his head are all the way up as far as it goes. We're still trying to do a Cone Beam and trajectory planning down essentially in his proximal thighs.

It did combine all of the things you're mentioning, that we had to say trajectory planning doesn't really work here. Sometimes the angles that we choose, the machine will just tell you, not achievable, can't do it. You still couldn't access, which we did under fluoroscopic guidance and you still could visualize it with Cone Beam CT, but we did have to utilize those things we talked about before where we said we're almost in the right place, but I just have to use tactile feel to move myself 5 millimeters more caudal and more medial and then we were perfect.

Nobody wants to hear that you were okay, not terrible. We were really happy to be perfect after using that combination of knowledge and tactile feel. The short again, I think, is there's a combination and in my practice, I find that using that combination keeps me out of CT. I continue to live in CT for lung, but everything bone I think is better under fluoroscopy with the ability to do Cone Beam.

[Dr. Jacob Fleming]
Agreed. I think there's a lot to the hybrid approach. Sometimes for some of these very complex cases, I could see the benefit of having a true CT angio system, but in most cases that's probably like using a rocket launcher to hunt geese. I agree that what can be done in a standard angio suite, or even nowadays certain C-Arms have Cone Beam CT capability. That starts to extend into even the OBL setting.

[Dr. Dana Dunleavy]
It does. The one thing I would just say to that is depends what type of anesthesia you're doing. I think that those CRMs with Cone Beam are getting better. In general, they take a little bit longer, and a little bit longer means if the patient moves it all it's no longer useful. For those people working in ASCs, as an example, where patients under MAC, I think that works great for many of our patients. I find again, in my practice, you're oftentimes getting patients that neurosurgery and ortho, and PM&R are sending to you because they have severe COPD and cardiomyopathy and various other issues that don't allow you to sedate or do anesthesia. If the patient's moving, it can be challenging to do one of these really slow-speed Cone Beams.

(6) Interventional Radiology’s Expanding Role in Cancer Pain Management

[Dr. Jacob Fleming]
Yes, that's really good information to consider, or something that we are used to as interventional radiologists, whether the patient passes the sniff test in terms of you look at him, and you say, "Can we do this under moderate?" Can we do that or MAC? Sometimes you just know it's going to be a general case. It's very helpful to have that. It's another reason why there's never going to be a point where all of these cases can be done in the OBL. There's always going to be a need for those higher levels of care and being able to do it either in the hospital or ASC setting. That is all I had, Dana. This has been an excellent conversation. I want to know any final thoughts. I do want to hear more general thoughts, but any final thoughts on the topic of bone tumor ablation and mechanical augmentation?

[Dr. Dana Dunleavy]
Overall, I just hope that people can see the passion that many of us across the country have because these patients come back, not only the patient, but their families, and really tell you this is the greatest thing you could ever do for a cancer patient. I neglected to mention that when I was in high school, my close friend's sister was diagnosed with leukemia. At the time I didn't know why, I guess I must have at least have shared with her my passion for healthcare to some degree, and that she told me she was counting on me to prevent this from happening to other children, and that I would have a role in oncology.

I didn't really see how until I ended up in this land. With doing bone tumor ablation, again, you have patients that come in, in a wheelchair, and they walk out, and they live a good life. I think this part won't be in video, but you can see here we're talking about New York matters. I think that this is one of many organizations. Obviously, I'm in New York, one of many organizations that's really focusing on preventing opioid overdoses and complications and hospitalizations related to narcotic use.

We have an amazing ability to help people that way. I think that the best way we can do it to avoid systemic therapy and complications is to be targeted. One of the terms people use for bone tumor ablation is targeted radiofrequency ablation or t-RFA. I think that the whole life that you're living right now is targeting things towards people's pain. We didn't have enough time to talk about NCCN guidelines, but remember that every year there's something new in NCCN focused on pain, and that pain actually, not only is important for people's quality of life, but actually has survival implications.

There's more and more emphasis not only on bone tumor ablation, or not only on vertebral augmentation but all the things that you and others are doing, including dorsal column stimulation, nerve blocks, rhizotomy, pumps. There's just an enormous amount of opportunity for us to help and I think that we call ourselves interventional oncologists. I think that there's a big opportunity for us to include treating people's pain within that category of interventional oncology.

I guess the last piece of that would be some of the adjunctive things that I think that you've already included in these MSK discussions, but talking about sacroiliac dysfunction, talking about painful diabetic neuropathy, again, I think that's a huge one that we'll probably come back to because many of our colleagues do a lot of arterial work, or maybe they do a lot of venous work. They're seeing patients with leg pain. One of the common things that I hear from the vascular surgeons is, it's really frustrating to revascularize someone's leg and you're really proud of your work, and the patients really disappointed because they still have leg pain.

Again if people haven't heard it, doing neuromodulation for painful diabetic neuropathy actually even has better outcomes than treating non-surgical pain, back pain, or failed spine surgery back pain. We're talking about really great outcomes. Some of it that's really fascinating. This is data that's been presented at the ADA and other types of societies unrelated to us, but is that you have improved innervation in the legs and the feet. People that had paresthesias or numbness in their feet because of diabetic neuropathy improve their sensation within their feet, and they improve their A1C.

I guess you can tell that I enjoy the world of changing people's lives through improved quality of life and improved functional abilities. It all fits in this world that I think that we enjoy. It's very minimally invasive. It's image-guided and includes all the anatomy we enjoy. It's still what we may say is an extension of orthopedics and neurosurgery. A lot of opportunity, and I think we're really learning now the next frontier or steps that we're taking is how do we also help people with neuromodulation within the oncology world. There's a lot of effort going into that.

[Dr. Jacob Fleming]
Absolutely. I'm really glad you brought that up. That's something that I wanted to throw out there to our listeners, definitely, as you and I were talking about earlier, a discussion unto itself. A lot of exciting stuff happening there, I think a lot of potential for involvement, especially for interventional radiologists who are providing these ablative diagnostic capabilities to extend that into neuromodulation, and targeted drug delivery. That's something that we really want to discuss in the future.

Also just bring a general awareness of the capabilities of those techniques, like you were saying, and painful diabetic neuropathy, definitely something we'll get back on very soon because this falls into the realm that interests people like you and I so much of situations that otherwise don't really have a very good solution. I think we've really gotten to talk about that today. It's been a fantastic conversation. I want to thank you for your time and humoring my many tangents. I've thoroughly enjoyed talking to you, Dana.

I want to, again, show my appreciation for you taking your time to talk to us about this. As always, I like to end by asking my guests about what on the horizon are you most excited about right now. We talked about a lot of things that are here and that are coming. What is something that you're really looking forward to being perhaps the next step for us, whether with oncology patients or something else?

[Dr. Dana Dunleavy]
I'm excited about too many things. To try to nail it quickly, I think right now we're working on three columns support for reducing adjacent level fractures, trying to really identify what the best techniques are to reduce additional fractures. I'm excited about those two areas we touched on at the very end neuromodulation for neuropathy, and for cancer pain, I would say that that is the one that's really clinching it for me right now because those are really growing problems.

The final would be-- there's several clinical trials being involved now including us as interventional radiologists for sacroiliac joint dysfunction. As Wayne alluded to, when you start asking and examining for it be amazed how common it is. I've been honored that the neurosurgery colleagues have supported me in that because it is one of those crossover areas that can be considered surgery or can be considered minimally invasive. I think it really is incredible to help people again, in a way where they said for 10 years, "I've had this pain but has limited me from doing things I want to do." We now have the ability to make this better and less invasive than ever.

That takes me to the last, last point that you said that we can't do all these things in the OBL. I think that the OEIS has also demonstrated that as well, and that all of us that do work not only at hospitals, but either at OBL or ASC, and many of us have done most of it at the OBL, must start thinking that if we want to be comprehensive, it probably won't all be in an OBL and start thinking for the next three to five years, how we want to develop that.

[Dr. Jacob Fleming]
Excellent. Just a lot of great topics to think about and have you back on the show in the near future. Dr. Dunleavy, thank you again so much for your time. Any closing thoughts?
[Dr. Dana Dunleavy]
No, I really appreciate it, Jacob, you're amazing that you put so much time into this as a fellow, it's really incredible. Thank you for having me.

[Dr. Jacob Fleming]
Well, thank you. Honestly, these conversations give me so much energy and really keep me going. I want to thank you for coming on my show tonight and like I said, won't be long before we have you back on.

[Dr. Dana Dunleavy]
Thank you.

Podcast Contributors

Dr. Dana Dunleavy

Dr. Dana Dunleavy is a musculoskeletal and vascular IR in Buffalo, New York.

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, October 18). Ep. 33 – New Frontiers in Spinal Tumor Ablation & Augmentation [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.