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BackTable / MSK / Podcast / Transcript #47
Podcast Transcript: Kyphoplasty Evolution: Steering Toward Targeted Therapy
with Dr. David Prologo
In this episode of the BackTable MSK Podcast, Dr. Dana Dunleavy interviews Dr. David Prologo about his perspective on current advancements in MSK interventions, including steerable spine needles, thermocouples for radiofrequency ablation, and the growing importance of advocacy and longitudinal follow up for patients with chronic pain. Dr. Prologo is an interventional radiologist at Emory University. You can read the full transcript below and listen to this episode here on BackTable.com.
Table of Contents
Refining Minimally Invasive Spine Interventions with Next-Generation Devices
Optimizing Cement Fill & Procedural Efficiency in Spine Interventions
Enhancing Bone Tumor Ablation: Device Selection & Safety
How Case-Based Learning Improves IR Pain Procedures
Advancing Spine Ablation Precision with Thermocouples
Why Longitudinal Patient Care Matters in IR
Collaborating to Advance the Future of IR
Steerability in Spine Procedures: Enhancing Precision & Outcomes
Exploring IR’s Role in Weight Loss & Surgical Eligibility
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[Dr. Dana Dunleavy]:
All right. Thank you, Dr. David Prologo from Emory University. Third episode. Really fantastic. Thank you for doing it again.
[Dr. David Prologo]:
Thank you for having me. I was talking before we went live on the recording here. It's quite an honor to be on The BackTable Podcast. In the world in which we live, this is a very popular platform, and you all have done such an incredible job that this is like getting picked to be on CNN or something. I'm proud to have been invited. Thank you.
[Dr. Jacob Fleming]:
Obviously, we've spoken a lot about your credentials and your life and experience, but things have changed a bit over the last year. Can you tell us about your new role?
[Dr. David Prologo]:
I can. I'm the division director now at Emory University in the Emory Healthcare Network, which translates to a large group of currently 22 interventional radiologists covering eight hospitals, including a large level one trauma center, a dedicated cancer hospital, and so on. We've been growing and are under new leadership and on an exciting trajectory.
I hope that you don't mind if I use this platform and this chance to say that in order to continue on that trajectory, we are hiring excited interventional radiologists who want to do the things that you all talk about on The BacktTable Podcast, who want to push the edge, who want to teach, who want to innovate, and in fact, just want to work clinically in a peaceful environment. We've got a lot of different sites, and we're growing fast. I appreciate you allowing me to plug that. We're hiring, so call me if you're interested.
[Dr. Jacob Fleming]:
You're only allowed to plug it because it is such a great opportunity. I've firsthand had the chance of visiting, didn't do any training or working there, but seeing the environment you work in and some of the other faculty, like Dr. Kim, that are doing incredible work under you and with you. It's very frequent that we have conversations on BackTable about rewarding practices and opportunities to change your career. When I was visiting you talking about some research projects that you're really amazingly doing, part of the discussion was that if you could come into your office and just publish papers and do legendary things, that would be your dream. I think you're doing it.
[Dr. David Prologo]:
That would be my dream. To be honest, I didn't realize that a place like Emory existed prior to coming down, interviewing, and spending some time there, and starting to work. What I mean by that is you're surrounded by-- there's a certain faction of us that just can't turn it off, right? It's sort of in our DNA and we want to solve these problems and we want to do these high-end things and we want to take care of these patients.
The first thing I found when I came to Emory 10 years ago that struck me was like-minded people like you. To meet someone like you, for example, I'm surrounded by people like you. That fellowship is hard to find, right? If you have an interest in whatever it might be, rugby or knitting, and you find yourself surrounded by people who can talk about the nuances of knitting and the challenges of knitting, and all of a sudden, you're having this back-and-forth conversation and you realize that being around like-minded people provides you a fellowship and a sort of human interaction thing that's very supportive and very kinetic. That was the thing that I found at Emory.
Then the second thing, and at this point, I'm not selling Emory. I'm just sharing my experience. The second thing I found there was straight, objective infrastructure support. Where I had been previously, you might have an idea and then walk around the hallway and share your idea here and there, but there was no bridge to translation of that idea to commercialization, for example, or grant funding, for example. Whereas the opposite is true at Emory. There's a bridge there full of people who are employed to help you make these ideas a reality so that you can make an impact on a larger scale.
When I found those two people, and I've long since talked to my wife and my parents and said, coming to Emory for me was like signing an NFL contract. What I would imagine signing an NFL contract must be like because they want you to play football and you want to play football. You find this arrangement where they're going to pay you and support you to do the things that you want to do. That's a great thing to wake up to every day. It's been a real blessing in my life. I've been very lucky. I'm excited to share that opportunity with anyone else who might be out there in the position where I was, where I was sort of swimming upstream and felt like the outsider because I wanted to do X, Y, and Z. We welcome you here and we are going to support develop you.
[Dr. Jacob Fleming]:
Similarly, I think SIR has been lucky to have you, but also, your career now has allowed you to do some pretty interesting things with SIR. What is your role there now?
[Dr. David Prologo]:
I am the Director-at-Large, which is a seat on the SIR Board of Directors. In recent years, some great minds led by Raj Patel and Alda Tam and a few others reorganized the Society of Interventional Radiology. Prior to that reorganization, the SIR had a reputation sort of founded in the kernel of truth of being an internally fed society or institution, a so-called old boys club, if you will.
Those leaders that I mentioned went to great lengths to reorganize the governance and reach out to interventional radiologists all around the United States and the world to access all of the great minds and then create this matrixed sort of cross-reporting and cross-communicating structure so that now if Matt Hawkins has expertise in reimbursement and policy and advocacy and someone over here has a new device for which they need reimbursement, in the past, these two may never meet.
Under the new governance structure, which includes the Executive Board that I'm a member of, to answer your question, allows and encourages those conversations. I've seen those cross-conversations translate into action steps that downstream impact us on the ground. The most simple example I can give is work that Ammar Sarwar has been doing for years that now allows us to get paid for MR interventions, for example, and on and on and on.
The Society has been also a great influence in my career. You are also involved in one of the service lines, of course, Vice Chair of the Clinical Specialty Council focused on pain management. You can see how that work translates not only into education but into advocacy, and hopefully, dissemination of information. The Society now is not your SIR from 10 years ago where it's just four or five legends and nothing else. It's impactful now. It's far-reaching now.
Refining Minimally Invasive Spine Interventions with Next-Generation Devices
[Dr. Jacob Fleming]:
Yes, I've really enjoyed taking the opportunity to work with you and others to see how we can change the course and address what the needs are today just as I think the group at BackTable has. To focus, we wanted to get pretty technical and nerdy now because, as we noted, you were here back in the day with novel bariatric treatments and then back again with advanced minimally invasive pain interventions.
Now, to get a little bit into detail, you've had some pretty brave articles including some of your pelvic anatomy and doing cryoablation. Some of the questions that have come up, we've had vertebral augmentation discussions and bone tumor ablation discussions, and some of that comes back into specific devices and techniques. Do you have any comments just in general about being less invasive or being more targeted?
[Dr. David Prologo]:
I do. I do have comments about that. If you don't mind, I'll start even farther out, sort of at 35,000 feet, because at the end of the day, all of these topics, as specific as that question may be, are tied to larger initiatives that we care about, like practice building, for example. If we're talking about kyphoplasty and vertebroplasty, and we're going to drill down on the evolution of the techniques, I think it's important first to point out that the kyphoplasty-vertebroplasty service line or business line is a good example of how we as hospital-based interventional radiologists can be first in line to take care of these patients and to get these cases and to do these rewarding procedures and to help patients.
What I mean by that is there are procedures that other specialties can do. We all know that. We face that all the time. Being in the hospital allows us to potentially be first. If we can convince potential referrers in the emergency department or on the floor to call us when you see a fracture, or even our own diagnostic colleagues to call us when a you see a vertebral body fracture, we have the ability to get to that case and get it done and get the patient out of the hospital and affect the impact of length of stay, thereby helping the patient and helping the system just by being present and being responsive and having a system.
Kyphoplasty is a good example of how we can build our own practices and lay down foundations and build networks and take care of patients. I like kyphoplasty for that reason. What does that mean in plain language? In plain language, it means if you're young and you're coming out and you're at a new job, if you go to the ER, for example, and you say, "I'm here and I will take this patient off your hands, just call me and that's all you have to do."
They, as busy practitioners, know that one call means that you're going to put this patient in the CDU, order the imaging you want, make them NPO, do that case tomorrow, and send that patient home. Then that's a big difference between getting admitted and multiple consultations and multiple days pass and the patient is in pain this entire time and so on and so forth.
As a new person out or an older person at a new place, I would encourage you to start your at least pain fraction of your practice around kyphoplasty and vertebroplasty. That wasn't the question that you asked, but I just wanted to throw in that clinical context and how it's all tied together to things that we care about.
What you asked about were the evolution of the devices, and we've seen the evolution of the devices go from straight needles that were made to be hammered into the vertebral body and either installation of cement or a creation of a cavity with a balloon and subsequent installation of cement to devices that can now be guided into the vertebral body are already reshaped. They're shaped to cross the midline or whichever way you aim them if you're coming in low to go high. Those can also accommodate a balloon and subsequent cement installation. Then we've seen the evolution of a radiofrequency ablation probe that goes through the coaxial anchor that we put there in the cases where we want to ablate a tumor and also ameliorate that contact between the neoplasm and the bone.
Then finally, Merit, in particular, has developed a device that is sort of the next step beyond a preformed directional device used for kyphoplasty, vertebroplasty and/or these ablations, and that's a steerable device. That's a device that can be put in through your coaxial anchor. You can pick a direction and then sort of turn the knob and really steer the device to the location that you desire. That gives us much more specificity for vertebral bodies that might be compressed and create a difficult angle or vertebral bodies that might contain a tumor that's in a particular spot and we want to target. I like them a lot.
[Dr. Jacob Fleming]:
Yes. I think there's a couple examples we could give and you could address yours. One is, I talk about safety and there was a local case where someone tried to get access to the vertebral body and end up going extra-pedicular, presumably by accident, caused a big venous plexus hematoma that required the patient to live in the hospital for a few days. Some people talk about trans-pedicular as the safest and most appropriate unless you have a reason you can't do it.
[Dr. David Prologo]:
I might gently push back on that a little and refine that to say that trans-pedicular is probably the safest route because you avoid these vessels that are on the outside and you avoid the neural structures that are on the inside or medial and lateral, respectively. If you can take the angle that you want through the pedicle, then you're always surrounded by bone and it's a safer approach with less damage to those surrounding structures.
Where that falls apart is if you've only got a straight needle and the angle that you need to stay on the pedicle might not result in the needle being where you want it at the end of the advancement, right? I have to take a particular angle in order to remain trans-pedicular. I might end up more lateral than I'd like to be.
That is where these steerable devices really come into play. You can ensure that you're on that pedicle, and even though your target, which is straight ahead at the beginning, isn't or is suboptimal, once you get into the vertebral body, you start to steer this thing in whatever direction you want. It can be cephalad, it can be caudal, it can be medial, it can be lateral. Therefore, stay on the pedicle and avoid any damage to these surrounding structures. That's where the complications arise.
[Dr. Jacob Fleming]:
I think as you are noting for anyone that hasn't utilized these devices is you can articulate them as much or as little as you want so it gives the control to the operator.
[Dr. David Prologo]:
Right. That's exactly right. It's important not only if you're targeting a specific portion of the vertebral body, but sometimes the very nature of the angle that you have to take in order to stay trans-pedicular isn't going to end up in the vertebral body at all or is going to end up too far posterior, for example. Even the pre-curved devices that some are made by Stryker, for example, will help you end up in a different place. The ability to steer the inside of the needle as you're moving forward in real-time as you're watching has been quite an advance.
Optimizing Cement Fill & Procedural Efficiency in Spine Interventions
[Dr. Jacob Fleming]:
Now, even for osteoporotic vertebral compression fractures, traditionally with what we used to call the gold standard of bipedicular balloon kyphoplasty, in that case, most people would put their bipedicular balloons in the lateral plane and just inflate and then go straight to cement. With these larger unipedicular steerable balloons, are you still inflating in the lateral plane or AP as well?
[Dr. David Prologo]:
I like the lateral plane. I think it's a function of my training and my time and trouble being cement going posteriorly, right? I always start in the lateral plane, but you can also look in the AP plane and see where you are with regard to the medial, lateral, or central portion of the vertebral body. If you have biplane, if you're lucky enough to have biplane, then it's really great. You can just look in both planes. You do need to see the AP view with the steerable devices. It's unipedicular, right?
One thing we didn't mention was that if we sort of jump from this conversation, this comfortable fireside back table conversation to the "real world", we hear that term used so often, we're all quite busy and we have a lot of cases to do and other things to get to. Even before the invention of these pre-curved or steerable devices, I think I was always trying to do these cases from one side to get done. It takes a lot more time to get that second one in on the other side.
If they don't cross and they don't touch, then you end up with two pockets of cement oftentimes in a cavity that you created with a balloon. If the gold standard here or the goal is to stabilize the fragments, then just filling those two pockets might not always give you your best clinical result.
[Dr. Jacob Fleming]:
I think you mentioned some great examples. Another couple examples that some people will use is increasing marijuana use for various reasons and other types of substance use or maybe even cardiomyopathy, COPD, all reasons that we either fail to adequately sedate or might not feel that there's a lot of safety to sedate and perhaps there's a benefit there to getting a bi-particular fill with a unipedicular access.
[Dr. David Prologo]:
Yes, indeed. You're right. In addition to wanting to get cases done and get the day done, there's this shortening of the procedure time in general, which we know is better and safer for the patient. That said, there's been recent discussion about moderate sedation versus using our anesthetic colleagues for these cases.
I actually remember recently reaching out to you to ask about this. It seems to me that if we can get the cases done with anesthesia, if we have that resource and the patient is not feeling any of the procedure, not moving, and it's a controlled environment, I think that I favor that. If we're outside of the hospital and we're sort of relegated to moderate sedation for one reason or another, then certainly, a unipedicular approach has the advantage of shortening the procedure. That is significant and a very good point you bring up.
Enhancing Bone Tumor Ablation: Device Selection & Safety
[Dr. Jacob Fleming]:
One of the interesting discussions has been, when we get into all types of different modalities for ablation, sometimes people will say, "Well, Majid can do these really unique microwave cases in the spine and Prologo can do these crazy cryo-neurolysis cases," but how do we take the Jack Jennings approach and just make this completely simple and safe to make improved access and widespread use? Do you have any thoughts in terms of different modalities and how we make bone tumor ablation accessible to everyone?
[Dr. David Prologo]:
Bone tumor ablation, as it applies to these new devices and in the context of steerability, the only steerable bone tumor ablation set that I'm aware of is the STAR ablation device now marketed and controlled by Merit. Then, of course, we've got the Osteocool device by Medtronics, and now recently, OptaBlade from Stryker. The question is, how can we make this a procedure that we can all do safely given the differing products and the differing angles of each one of our patients and the different skill sets, presumably cross-sectional versus fluoroscopy?
My answer to that is, I think the great majority of these cases from T5 down can and should be done in fluoro. The reason that I say that, I didn't think that for quite a while, but the reason that I say that is because the angles that are created in the thoracic spine by kyphosis, scoliosis, et cetera, can be accommodated for with an II that you can move in all four directions. When you take that same patient to CT, unless you're going to tilt the gantry and you start to work in the axial plane, that pedicle is almost never in the axial plane.
This is a classic case of us trying to put a square into a round hole. We want to see a nice axial cut where we have two needles that are trans-particular and land in the middle of the vertebral body. That's really not the angle. I think, for that reason, they should be done in fluoro. That said, the transition to fluoro in a high thoracic vertebral body, there's a high learning curve there, a steep learning curve would be the more appropriate way to say it, because you've got to understand what level you are on and you've got to be able to sort of phase out all these other structures that are in the way and you have to realize that the risk is higher if you miss because there's a lot of critical structures around there.
As we're talking about this, Dana, I hope you don't mind, I'd like to drop in a pearl for any of the young listeners. When you have a lesion in the thoracic spine, it is very important, it is imperative that you have an entire spine image from MRI. What do I mean by that? If you get a thoracic spine MRI on a patient who came through the ER, and so when you show up in the morning, you've got a patient with a fracture and a thoracic spine MRI, and you can see this level and you're ready to take the patient to fluoroscopy.
What you don't have in that situation is the lumbar spine. When you go to localize that vertebral body that some diagnostic radiologist has labeled, you have to count from somewhere. You either have to count from the bottom, which is much easier, or you have to count from the top. If you don't have the corresponding vertebral bodies on some other image, then your counting can be off, right?
Someone called that T5. You put the patient on the table, you start counting from below. If that patient has 6 vertebral bodies or 13 ribs, if you're looking at the AP, then your counting is going to be off and you're going to land at the wrong level. It's always important to know, however you intend to count during the procedure, that you have that MR image projected in the room and you can correlate where you're going to start and where you're going to end up so you don't end up cementing the wrong level.
How Case-Based Learning Improves IR Pain Procedures
[Dr. Jacob Fleming]:
It's a great point. I was once told, "Dana, you got to stop worrying. You got to learn from mistakes." I said, "No, I'm going to learn from your mistakes. I'm not going to make those mistakes." Wrong-level surgeries happen. I think that there are things we can learn from that and how to avoid it. Now, there is this very fancy new book that came out called Advanced Pain Management in Interventional Radiology. I'm curious if you could tell us about your book and also if you cover simple things like that in there, or is that not advanced?
[Dr. David Prologo]:
I appreciate you asking about that. Let's start with the title. We, as interventional radiologists, have access to two special things. The first one is a skill set that we work on for many, many years that allows us to use imaging guidance in an advanced way, right? This is what we learned for all these years to use this imaging guidance. I think that qualifies us as advanced.
The procedures that we do uniquely in interventional radiology to manage pain are, for that reason, advanced relative to all the other procedures being done by other specialists. That's sort of where the advanced comes in. Interventional radiology, we're doing advanced interventional pain, and we'll leave the bread and butter stuff for everybody else.
Secondly, the book was originally driven by Charles Ray, who we should acknowledge as one of the fathers and trailblazers for pain management in interventional radiology. He laid the groundwork for a lot of what we do. It was an honor for me to be invited to work on that book. To answer the third part of your question, we do talk about exactly those things. Dr. Ray wanted this to be a case-based book so that if you had a case in front of you, you could take this book and find a similar case and then walk right through it, including all the things that we have done wrong, all the mistakes that could be made, and any of the literature that supports what you're about to do.
The book is called Advanced Interventional Pain Management in Interventional Radiology or something very close to that. The editors are Charles Ray and myself. It's available at Theme. I was excited to be a part of it because, like you, as we go through our lives and we try to get this information out, the following question comes up over and over and over again. Where can I go for a reference point? Where can I have a textbook or a web-based repository that I can use as a reference point as I grow my business?
It just came out last month. It's all sort of timely. None of this is antiquated. It's all real-life things that we're facing now. People can get that book and have that as a reference point for just about every interventional pain management procedure you can think of, from spinal cord stimulators to biologics to epidurals to kyphoplasties and vertebroplasties. I appreciate you asking about that as well. That's a labor of love. That's, I hope, an answer for a lot of people who are looking for a reference in this space.
Advancing Spine Ablation Precision with Thermocouples
[Dr. Jacob Fleming]:
I think we talked about the greatest opportunity, right, is to apprentice with you and others that lead the field. Not all of us can do that. Having that as resource like that is really wonderful. Now, how about in terms of some of the aspects of your career that we all look to you for in terms of really complex pain syndromes and cryoneurolysis, going back to radiofrequency, we think about those differences of being able to visualize what you're doing with cryo versus how do you know what you're accomplishing with RF. Do you utilize anything? There's been a lot of discussions of how we can address, whether that's just research in terms of time and temperature, or whether we're going to use tumor biology, or whether you use thermocouples. Do you use thermocouples for your tumor ablation?
[Dr. David Prologo]:
I do. Admittedly, I am trusting in the predetermined ablation zone sizes that correspond to a thermocouple reading. One, again, back to that STAR ablation device, and the thing about the STAR ablation device, by the way, this was the system that I started with. There was something before that called the Spinewand. I'm not sure if you ever used that, but that was the original idea of, "Hey, we can put a radiofrequency ablation probe in here." It was very labor-intensive and you had to cover the whole thing with plastic and there were a bunch of pedals and all this kind of stuff.
After that, for many years, I used the STAR ablation device. One of the most impressive developments that I have seen in this space involves that STAR ablation device, and it is the thermocouple, right? The thermocouple, so what's a thermocouple, by the way, for people who are listening, it's basically something that gives us feedback on temperature in the ablation zone. Historically, for whatever reason, we would put these, for example, on a cryoablation probes, we put them on the tip. It provides us this very low temperature that's of really no clinical value to us, what it is at the tip. Then we start to put them in the middle.
For example, I think the Medtronics ones are in the middle and the old STAR ablation ones were in the middle. Now what Merit has done is put these thermocouples proximaly on the probe. What that means is that you start this ablation zone and it expands in all directions. As it expands proximaly up the probe, the temperature reading at that thermocouple goes up. When you hit a critical number, you know the shape of your ablation zone now. This has all been, of course, verified on bench data and animal data as well.
We don't have that option in any other device, by the way, to do spine ablation. There are two. We can get the thermocouple read from-- it's a proximal thermocouple, but relatively speaking, it's the most distal one on the probe. Then there's a second one, even more proximal. If we let the ablation zone-- and you can see these, they're radio-opaque. If you let the ablation zone continue to expand over time, you'll see the reading for the second thermocouple go up as well. When you hit a critical number, you understand the entire geometry, or it reflects and correlates with the entire geometry and the measurement of the entire device.
This is not what you asked, but I can't help but say this. I'm working on a cryoablation device. One of the things that people have often asked during the cryoablation cases is, what is the temperature in vivo, right? We did a lot of experiments to show that the actual temperature in vivo is much warmer than the projections from the gel phantoms. What you really need is a thermocouple there to tell you what the temperature is. If I do an ablation in your liver that's vascular will be a lot different than if I do it in your calf. Those thermocouples are important and can have important clinical translations.
[Dr. Jacob Fleming]:
I think for people to think why it matters, right? One would be achieving clear margins, if that's your goal, so an efficacy standpoint. The other, which I think that you're known, again, as a world leader on is, how do we protect important structures?
[Dr. David Prologo]:
Right. How do we protect them? In the case of spine ablation, which is what we've been talking about tonight, as you come posterior, that's where the spinal cord is. That's where complications for the patient are going to happen if we heat up critical neural structures, right? Then, of course, the step beyond that is when we know we're getting close to a critical structure, the ability to adapt and conform that ablation zone. I think that's going to be the next technological step. We're working on that. It's a difficult thing to do, but that's the wave of the future, to be able to control these in real time, in space, so that we can avoid critical structures and keep non-target structures safe.
Why Longitudinal Patient Care Matters in IR
[Dr. Jacob Fleming]:
One of the cool things you shared with me is, and I think, sometimes we got to say for a legend like you, the bravery to actually discuss and even publish complications. Can you tell us a little bit about your fancy titled article about the pelvic structures?
[Dr. David Prologo]:
Oh my gosh. The one that I called ablation zones and weight-bearing bones, is that the one you mean?
[Dr. Jacob Fleming]:
That's the one I love.
[Dr. David Prologo]:
I had a fight with the JVIR editors to let me keep that sort of rap line in there because it rhymes. We published that for exactly the reasons that you describe. We were making mistakes and patients were having problems and we got some follow-up MRIs that showed our ablation zone. When you compare that to the CT image that we were using for guidance, there was quite a difference there. We learned things like it's colder beyond the ablation zone than you think, or a better way to say that is it's cold enough to cause damage outside of that ablation zone. It's something to think about.
Then other situations such as lytic lesions in the proximal femur, for example, potentially resulting in a complication. Earlier, we talked about having the entire spine there so you don't do the wrong level. I think one of the most dramatic things that happened to me in my career was I had a patient who had a traumatic fracture of T12. I ended up doing a kyphoplasty and cementoplasty at what I thought was T12. Even looking at the AP image, it was the vertebral body that had the last rib attached to it. It wasn't compressed because it was a traumatic sort of almost distracted vertebral body.
I share that complication for a couple of reasons. The first one is make sure you have that counting MRI. I think that probably would have saved us in that case. Second of all, at that time, this is years ago, we didn't have longitudinal follow-up. We didn't have longitudinal care. This was somebody who came through. As an inpatient got referred to us, we did the procedure. I saw her afterwards. She seemed okay. That was the last I heard until a month or so down the road when I get a call from an outside hospital that she had abdominal pain and cement at the wrong level and was septic and paralyzed, and not really, but just all of these things that they ended up listing.
To bring in things like we brought in practice building when we talked about going to the ER, I would bring in the importance of longitudinal care. Every patient that you touch as an inpatient referral should be tightly followed up as an outpatient. If I wanted to neatly tie all that in a bow, you tightly follow them up as you should, and you'll protect yourself against the surprise that I got. You will also build your practice because that person is going to know somebody else who has this or that or this or that. It's an example of why we want to make sure we follow these patients tightly down the road after we do a procedure, any procedure. We just happen to be talking about kyphoplasty.
[Dr. Jacob Fleming]:
Yes. Then to go back to your fancy article again, I think one of the things that you nicely describe is that we as an advanced specialty have all these different modalities at our fingertips. It is a lot to keep up with. One of the things you pointed out is that cryo and microwave don't respect the cortices. You have some femoral head fractures associated with that.
I think it goes a little bit back towards what you were saying with steerability as well as really understanding your ablation zone, because number one, we really don't want the common thing that I think you and I see where anything challenging perhaps in the acetabulum, in the sacrum, just gets told, "No, there's nothing to offer for you." On the other hand, we want people to understand how to achieve this safely.
[Dr. David Prologo]:
Right. Boy, I could go on for the rest of the night about those two points. The shorter answer is, how to do it safely. That's where I think these steerable devices and then the next iteration, which is going to be controllable ablation zones and the knowledge of the in vivo temperature, are ways to keep the adjacent structures safe. The former portion of that statement was that we tell them no. This is something that is sort of at the heart of everything I do now, which is avoid the binary response of yes or no to any patient that comes across your desk, as it were. If there's a patient who shows up to the interventional radiology service and they're in your consultant, they're asking you, where the universe has brought you two together, to solve a problem, which is likely complicated, right? Most of the time we have our bread and butter stuff, but we live really in that space where we're asked to solve problems.
If you're faced with a problem, we can use this sacral lesion. Let's say, it's really not doable, right? For some reason, we can't do our typical procedure and keep them safe. We say that an interventional radiology procedure is probably not the answer for you and then that's the end of it. Then we cut them loose to the universe, right? I want to get the message to all of my interventional radiology colleagues for as long as I can and for as long as anyone who is listening that the second that person presents you with that problem, that's your wife, mom, sister, friend now. You are obligated to find them a solution. Because as a patient with a problem, it is nearly impossible to navigate the healthcare system in 2024.
As a doctor, what you end up doing for your friends and your relatives and your loved ones and the quote-unquote VIPs, you don't always end up doing a procedure for them, but what you do always do is navigate the healthcare system for them. You find them what can be done in 2024 and then you follow through with the connection and the outcome to make sure whatever it is that can be done does get done.
Sticking with the sacral lesion example, if that's not something that I can do, instead of saying I'm sorry there's nothing I can do for you, my answer is I don't think I have a procedure that's going to help you, but either (a) I have an idea of something that will help you or (b) I'm going to find you the right place and the right person to make sure that we are doing everything that we possibly can for you. In that case, maybe the answer is an intrathecal pump. I haven't been trained to do those yet, so maybe I have to send that patient to Colorado to get our friend George to do it, right? The point really is that whatever the solution might be, it's going to be much easier for you as a patient advocate on the inside with your knowledge, experience and network to get someone the help they need rather than offer them a binary response that you can't help them.
I can give a quick personal example of where this really sort of slammed home for me. My daughter had right lower quadrant pain, and she's a high-level gymnast, high-functioning person, but this was doubling her over, right? We went to the ER and we were there and the surgeon came in. He did ultrasound and so on and so forth and, at the end of all this interaction, the ER doc and the surgeon are there and they say she does need an operation and she didn't have appendicitis and so it was nice to meet you, and they just left it there, right? Here I am now with a daughter who I know, for sure, is having pain and I'm on the other end of the binary she doesn't need an operation, good luck, right? And I'm a doctor and I'm on the inside and I have a particular interest in pain and still my response was, "What do I do now?" Right? Imagine if you're not a doctor, you're not on the inside and you might not have the intelligence level to navigate through this, you're going to need some help. I encourage my interventional radiology colleagues to be that help.
Collaborating to Advance the Future of IR
[Dr. Jacob Fleming]:
I love that and I think we talked a little bit about longitudinal care and practice building and I think you're helping with SIR to encourage a lot of these aspects. Can you address a little bit, we have our spring SIR meeting, what's planned for the fall?
[Dr. David Prologo]:
Yes. The plan for the fall. We've got, as you said, our annual meeting in the spring, which I encourage everybody who can make it there to come because, as I said early on in our discussion, that fellowship and that interaction is just priceless. You just can't beat being around other people who are doing your same job and being able to talk with them and bond with them. What the SIR has decided to do, again, recent brilliant leadership, is to create a fall sort of mini-meeting. The fall mini-meeting is going to be called SIR Edge, and it's going to be a split between portal hypertension and interventional pain management.
Also, there's one other little wrinkle here, in between there, the SIR has supported and generated a six to seven week webinar specifically focused on advanced interventional pain management and some of the topics that we have been talking about. Then at the Edge meeting, we'd like to have the hands-on portion to get your hands on these intrathecal pumps, your hands on these steerable devices that we're talking about to lock down that series that's going to be in the summer. That's going to be in Denver, Colorado and will be a smaller sort of more quaint gathering. It's going to be you, I think, are going to be there and we're going to answer questions in a much smaller sort of one-on-one environment and get this information across about what we can do for these patients.
[Dr. Jacob Fleming]:
I think it'll be wonderful because, despite all of our efforts to have more online resources, this field of interventional spine, interventional pain, is growing so fast, the fastest growing area of our society that we really couldn't fit it all in the annual meeting.
[Dr. David Prologo]:
Also, you're competing during the annual meeting with some other very important topics, right? Just meaning that the sessions are at the same time and also somebody has to stay home and work. This will give an opportunity for those who stay home and work or those who have to be at a different session during the pain management sessions of the annual meeting to really learn how to do these things and how to select patients and so on and so forth. I know I can't go on and on here for 50 hours, but if I could just tell one more story about taking care of patients, but I'll tie it to kyphoplasty because that's what we're talking about.
I think it's the best illustration I have of what I hope we will all do going forward, and it won't take too long. Two minutes. I got called for a patient, an outpatient, who had this lesion, they were calling, and it was like a T7 or T8 lesion, and it was essentially not just down on T1 and T2, but it was really almost black on T1 and T2. He was having back pain and he was referred to me for biopsy. How would you handle this case? Probably biopsy and simultaneous because what else is this going to be? It's probably going to be cancer. Simultaneous ablation and cementoplasty to get this guy out of pain, right?
The day he's there, the nurse says to me, you better come and talk to this guy. He's irate, he's out of his mind. I go in there. The entire room just reeks like cigarette smoke. And this guy's got poor dental hygiene. He's sort of slobbering the side of his mouth and he is yelling that no one is taking care of him. It's an important part of the story, by the way. He is yelling specifically that no one is taking care of him. I said to this guy, look, I promise you I'm going to take care of you. Whatever this turns out to be, I won't let it go, even if I do this procedure and you don't feel better.
We proceed to biopsy both these levels. We proceed to do ablation and cementoplasty at both of these levels and he doesn't feel great at two weeks and he doesn't feel great at one month. There are a couple lessons here. This is a technical lesson for the young people. We went back and looked at the images and there was a lot of still lysis around my cement. Was this cancer? Well, the original biopsy results for both levels said hemosiderin-laden macrophages, right? I have this guy back in my clinic and he's furious, still saying no one's taking care of him, which is correct. I've put him through a procedure so far, I have no answer for him, and he doesn't feel any better.
We bring him back, we biopsy again under CT guidance around the cement and then we do an epidural injection, which we'll sometimes do for patients who don't do after kyphoplasty. The biopsies come back the same, hemosiderin-laden macrophages. There's no cancer here, so that's good news for this guy. Here's the learning point for the young people. If you don't feel that, then these patients can have persistent pain. There was lytic, what I was calling lytic, but literally just space around my cement. There wasn't enough cement at either level. We went back in and we filled those levels finally and he felt better.
Finally, his pain was gone. He said to me, would you mind looking at these images that I had taken about a year ago? I was having a car accident in an ER. I said, sure. I find out during that conversation that his wife died in that accident, that he had developed some PTSD from that and also that his wife had taken care of everything for him, his COPD medications and so on and so forth. The day I met this guy, he was truly lost. He didn't have his wife to manage his medications anymore. He had emotional trauma. Nobody was helping him, et cetera, et cetera.
I go back and look at these images and those fractures are there. As it turned out, those fractures when he presented were never treated, never called, no one ever did anything about them. It explains why I got hemosiderin-laden macrophages out of the biopsy site and essentially he had been sitting on his two fractured bones for a year. Every time he went to the ER, people said, oh, he's just yelling and screaming because he wants to get drugs. Really what he needed was somebody to appropriately take care of him. I'm sorry, that was a long story. One in five patients is like that. One in five patients is going to take extra effort for us to navigate the system and go the extra mile to get them to a place where they should be in 2024, which is optimized as if they were our own brother or father. Thank you for letting me tell that story.
[Dr. Jacob Fleming]:
No, it's great because we're here or at least you and I intended to be here to get really nerdy into the details of technique. Really, when we think of two areas that you noted are big gaps, we talk about all the patients with neuropathy in our vascular clinics, talk about all the patients that have chronic or a disabling pain from cancer. What you mentioned in terms of neuromodulation and pain pumps is a gap for most of us that we really could be helping with, but technically very easy. It's really the clinical decision-making that's hard. I think we're trying to provide more resources for that. Have you provided any of that in your book?
[Dr. David Prologo]:
We did talk about practice building and we did talk about the difference between working in a hospital, working in an outpatient lab with regard to infrastructure. We did talk about longitudinal care. What I have found out, though, in my new job, is that these ideas that we have require not just us to be there, right? I just told this story, this big long story about how we took care of that guy, but it took 10 people to coordinate what was going on with his COPD medications, get him into a wounded warrior project. It took consultations to understand why I thought he had lytic lesions and he didn't. You really need human beings to provide that longitudinal care. Meaning, you need staff and you need advanced practice providers and you need nurses and you need people other than the operators in order to provide this longitudinal care. To answer your question, we talk about the importance of it, but translating that into reality is a fiscal and operational challenge.
[Dr. Jacob Fleming]:
I think that's why between the books, the webinars, the labs, and our conferences really trying to give people as many resources because we just can't address it all during fellowship.
[Dr. David Prologo]:
Right, and that's why this BackTable Podcast is so amazing. It's really one of the greatest things that's happened to our specialty in the last 10 years to give people access and to bring together these experts with experience and allow them to tell their stories. It's of incredible impact. I'm honored to be a part of it.
Steerability in Spine Procedures: Enhancing Precision & Outcomes
[Dr. Jacob Fleming]:
I appreciate it. I think it also gives us an opportunity, like you noted, to talk about complications or how we've addressed them, as well as some off-label use as well. I was recently meeting with our friend Junjian who Josh Hirsch refers to as probably one of the greatest future leaders we have. He's done some great research and clinical outcomes on different devices for basivertebral nerve ablation. I think it gets back to what you were addressing with lytic metastasis and the posterior central aspect of the vertebral body, is how do you target the most difficult part of the vertebral body?
[Dr. David Prologo]:
Right. Great question. The only way to get there, as far as I can tell now, is to use the STAR ablation device steerable component. I want to be clear that the steerable, and I recently learned this, admittedly, there's a difference between steerability and pre-curved, right? Pre-curved does allow you to put something into the vertebral body that will take a different angle, but steerability is something that allows you to get to something in real-time, right? If you've got a focus of a tumor in the posterior portion of the vertebral body, which by the way, is a difficult place for the radiation oncologist to treat. It's tough all the way around.
The way that you can get there is by putting your coaxial needle to the posterior border and then you can use this inner steerable osteotome and advance it, maybe you advance it in one centimeter and then when you turn the handle, which is outside of the body, the tip of the needle, the tip of the osteotome will actually turn. If you turn it again, it'll turn again. It'll turn 90 degrees. You can use that ability to turn 90 degrees once entering the posterior border of the vertebral body to advance to the center and ablate. That's how you can target. With any other device, you really can't do that. You just have to go straight in and you're going to get an ablation zone in the middle and oftentimes leave the middle posterior portion of it untouched. Then the radiation oncologists have to try to get to that. Of course, that's also the lesion that's going to end up in disruption of the posterior border and potential neurological sequelae.
It's been a brilliant evolution to watch the STAR ablation device, which I started with so many years ago, become better and better and better as they learn to steer this thing inside of a coaxial anchor straight to the target that you need. You can use that same. By the way, I am a consultant for Merit, not in the spine division, but I've recently reviewed some of their embolics. I don't have any personal gain from the use of any one of these different products. I just want to use what's going to help the patient. Hopefully, all those stories I told about taking care of the patient will lend me some credibility. I just want the device that's going to allow me to take care of the patient.
If that focus is in the posterior third in the middle, I've got a way to get to it. If it's not, and I have the same device, then I can go to the anterior two thirds on one side or I can cross the midline with that, if I want to stay unipedicular, or if it's a particular relaxed day and I just want a large ablation zone, we could put a second one in and do a bipedicular approach and create a large ablation zone with the same Merit devices. They also have pre-curved devices for osteoporotic compression fractures. You can use the osteotome in an osteoporotic compression fracture. It doesn't have to be a tumor.
All of these things allow you to have quite a bit of variability in one set. I remember when I was at the Merit headquarters talking about embolics and I remember saying that if we had everything in one set, in one place, that would be a lot easier than trying to get something from here and something from there. I think in the spine division, where I'm really not involved at all, other than as a user in this discussion, they've done that.
[Dr. Jacob Fleming]:
Just to clarify because not everyone has quite your spine experience, but you're addressing, right there, bone tumor ablation and what about to differentiate that from steerability for the basivertebral nerve, why is posterior central so important.
[Dr. David Prologo]:
Right. That's our target for basivertebral nerve ablation, which is a recently, as you know, exploding field for a population of millions of patients with discogenic pain and no other option. I'm sorry if I misunderstood the original question, but that's where the basivertebral nerve target is. That's where we want to be to essentially perform radiofrequency ablation, just like we do in the knee, just like we've been doing for 30 years for medial branch nerves that supply arthritic facets. In this case, we want to knock out the signal from a painful desiccated disc. Being able to get to that same location, in this case, non-osteoporotic, nontumor containing vertebral body but instead to make sure we target our nerve to stop the signal and improve symptoms in patients with desiccated discs. I didn't even think of that, actually. When I said that they add everything in one box there for you, I didn't even consider that. They really do. You can do all of these procedures with that same box.
[Dr. Jacob Fleming]:
Well, I think one of the things that a lot of people have been asking us is to really get into the details because it can be confusing for people having so many new devices coming at them. I think one thing that Junjian did nicely is show that the technique, depending on which device you're using, isn't the same. Temperature and time is different. Location is different. Just nice that we all have so many resources and, obviously, you've included him in these talks as we've changed kind of a lot of our mentors we've all had. Now, as a closer, we talked about the complex name you had for your advanced pain book, but then we got to go back in time and talk about The Catching Point Transformation. Anything new in that land?
[Dr. David Prologo]:
Oh, gosh, The Catching Point Transformation. That was a book and I think actually then at the annual SIR meeting, there's going to be a session about writing books. There's going to be a few of us there sharing the journeys of writing a book. That one, The Catching Point Transformation, was written for the general public as opposed to, of course, Advanced Interventional Pain Management, which was written specifically for interventional radiologists. The space there is evolving. To be quite honest, I think most people don't know this unless they know me personally.
The driver behind that book was sort of the same humanistic approach that I described for my guy with the traumatic induced old vertebral body fractures and so many others, which was that we weren't taking care of these patients. That was the driver behind that book because there were so many people for whom we would offer this "gold standard" of calorie restriction and exercise. It didn't work for 95% of the population or 95% of the people who tried that. Then we just cut them loose and said, "Oh, well, not too bad. Good luck." What has changed, to be quite honest with you, are these new peptides. I don't know if the humanistic drive is what led to the development of these peptides. I like to think that it was. Somebody was saying, "Look, we've got to help them in some other way instead of constantly telling them that they don't have willpower and that they're less strong and less worthwhile people than we are. Let's try and ease the burden by easing hunger." That was our idea with the cryovagotomy, but it seems that the peptides do decrease hunger. I think that's what's new in that space right now.
Exploring IR’s Role in Weight Loss & Surgical Eligibility
[Dr. Jacob Fleming]:
Okay. Just to tease it out one step further, I think each year, whether it's the Hopkins grads like me talking about B trial or the Emory grads focusing on all the work that you've done, is there anything clinically relevant for all of us that we could be contributing to avoid these really morbid obesity surgeries?
[Dr. David Prologo]:
Oh, wow. That's a tough one. We had, for a long time, focus on bariatric artery embolization and then we sort of switched to cryovagotomy and then there were these systemic treatments. I don't know as interventional radiologists, if we've clearly defined what our role is, but I will take this opportunity to highlight the space, the opportunity that's there for us, if we can hone in what our role is. What I mean by that is, if you take orthopedic surgeries, if you take knee replacements, maybe our role is genicular nerve ablation so that these patients can exercise and get to the BMI criteria that they need to be to get to surgery. Said another way, these patients are being turned away because of their BMI for hip replacements and for knee replacements, et cetera.
If we can accelerate the weight loss in order to get them the surgery that they need, that's a market for us, right? We haven't talked a lot about business, but that's truly a market for us, a space where we can insert ourselves, accelerate that weight loss using things like genicular nerve ablation so they can exercise, potentially cryovagotomy so they're not as hungry, and then get them past, what I call, the catching point, in that first book The Catching Point Transmission, get them past that catching point because once they've lost enough weight and exercise just enough, then it's the equivalent of the tipping point. If we can take this holistic approach to all of our patients, then we'll be able to find our role in not only the acceleration of weight loss for that population but the road home for everybody, for all of these patients.
Had a patient with chronically dilated calyx in his kidney, sort of an unusual thing like dysfunctional abnormality of his ureter on that side and just constant pain, and tried to take this approach. We tried to blade the aorticorenal plexus with alcohol in order to cut off the pain signals coming from his kidney and so on and on and on. The point is, at the end of the day, he needed an nephrectomy. What I learned during that journey is that urologists are trained that you don't do a nephrectomy for pain, right? That's what this guy needed, so he needed an advocate. Even though my certificate on my wall says interventional radiologist, in order to get him feeling better, he needed an advocate.
The answer to all of these questions, where our role may be in the acceleration of weight loss or the outside of interventional radiology cure for somebody in pain, it does really come down to advocacy. Advocacy, in my mind, really translates to asking yourself each and every time, and any trainees that are listening to this or any new docs that are listening to this, you really can cut through a lot of stuff by asking yourself, what would I do if this was my relative? You can figure out where your role is in the longitudinal care of the patients that we were just talking about, or you can honestly make the decision whether or not to do a procedure if you find yourself in a gray zone, by reflecting on just that question, what would I do if this was my relative, can help sort of guide your practice and guide your way over the years.
[Dr. Jacob Fleming]:
I could listen to you all night and I appreciate your leadership, education. Likewise.
[Dr. David Prologo]:
I could talk to you for the rest of the night. Anything I missed, Dave? No, sir. I just want to say again, thank you for doing this, right? Thank you for the effort and time that you put into this. You called me over the weekend, there's so much work that goes on behind the scenes here so that you can provide this material for your listeners and then ultimately impact the patients downstream. It's good work. It's God's work. I want to thank you for that.
[Dr. Jacob Fleming]:
Thank you for coming on.
[Dr. David Prologo]:
I, on behalf of all the people who listen to, and also I want to get a t-shirt because I'm walking around in these places, look, you have one off right now, you're wearing one right now. I get everyone has a back table t-shirt. No, it's amazing what you've done. I'm so proud of all of you guys. It's awesome.
[Dr. Jacob Fleming]:
Thank you. No, it really is the easiest, fastest, best way to share your knowledge and lifetime of experience with the whole nation and honestly the whole world. Thank you for taking the night.
[Dr. David Prologo]:
You asked me over the weekend, one of the ways to learn from me or learn from some of the great, we've got the 2024 Women in IR gold medal recipient Janice Newsome working at Emory and so many others. We've got Judy Gichoya working at Emory, who is truly an international expert in artificial intelligence, and that's an understatement for what she does, and so many other people like that. When you ask me that, the answer that I have is, "Come to Emory." Come to Emory, we've got a spot for you.
[Dr. Jacob Fleming]:
Fantastic. Thank you, David. Really appreciate it.
[Dr. David Prologo]:
Thank you, my friend.
Podcast Contributors
Dr. David Prologo
Dr. David Prologo is an interventional radiologist at Emory Healthcare in Atlanta, GA
Dr. Dana Dunleavy
Dr. Dana Dunleavy is a musculoskeletal and vascular IR in Buffalo, New York.
Cite This Podcast
BackTable, LLC (Producer). (2024, April 9). Ep. 47 – Kyphoplasty Evolution: Steering Toward Targeted Therapy [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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