Episode 19 - Introduction to Spinal Artificial Disc Replacement Surgery with Dr. Dom Coric
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Episode Summary
Replace defective joints in the knee and hips is not unheard of and there’s a big chance that you or someone you know has had this surgery done. But can this type of procedure be done to address issues in the spinal region?
In this episode of Back Talk Doc, Dr. Sanjiv Lakhia is joined by Dr. Dom Coric, who is an expert in spine trauma, spine surgery, and in particular, spinal arthroplasty. They dive deep into all aspects of artificial disc replacement surgery in the neck and lower back. Dom describes what happens during this type of procedure, which involves replacing the structural problem with an artificial disc, instead of the normally used spacers, rod screws, plates, etc. He also talks about the types of artificial discs that are typically used, how they have evolved through the years, and the differences between those that are utilized for the neck versus the lower back.
Dom discusses some exclusion criteria for artificial disc surgery. This procedure is recommended only for discs that are younger and don’t have spondylosis or wear and tear changes. Having healthy lumbar facet joints is an important factor as well.
Although this is a fairly new area in spine surgery and results are more visible long-term, there is a lot of cutting-edge research being conducted. And so far, the medical community is expecting positive outcomes with artificial disc replacement surgery.
Key Moments in the Episode
What is artificial disc replacement surgery 06:27
Incidence of sacroiliac joint pain after lumbar fusion surgery 12:06
What is an artificial disc 13:19
Artificial disc for the lumbar spine 17:18
Types of devices for low back versus neck 18:49
Exclusion criteria for artificial disc surgery 19:55
Positive outcomes for disc replacements in the neck and low back 21:30
Decrease in incidence of adjacent level disease with disc replacement surgery 22:35
Shelf-life of disc replacement devices 24:17
Lumbar facet joints 26:32
Dr. Dom's go-to health habits 30:13
Back Talk Doc is brought to you by Carolina Neurosurgery & Spine Associates, with offices in North and South Carolina. To learn more about Dr. Lakhia and treatment options for back and spine issues, go to backtalkdoc.com. To schedule an appointment with Carolina Neurosurgery & Spine Associates, you can call us at 1-800-344-6716 or visit our website at carolinaneurosurgery.com.
Replace defective joints in the knee and hips is not unheard of and there’s a big chance that you or someone you know has had this surgery done. But can this type of procedure be done to address issues in the spinal region?
In this episode of Back Talk Doc, Dr. Sanjiv Lakhia is joined by Dr. Dom Coric, who is an expert in spine trauma, spine surgery, and in particular, spinal arthroplasty. They dive deep into all aspects of artificial disc replacement surgery in the neck and lower back. Dom describes what happens during this type of procedure, which involves replacing the structural problem with an artificial disc, instead of the normally used spacers, rod screws, plates, etc. He also talks about the types of artificial discs that are typically used, how they have evolved through the years, and the differences between those that are utilized for the neck versus the lower back.
Dom discusses some exclusion criteria for artificial disc surgery. This procedure is recommended only for discs that are younger and don’t have spondylosis or wear and tear changes. Having healthy lumbar facet joints is an important factor as well.
Although this is a fairly new area in spine surgery and results are more visible long-term, there is a lot of cutting-edge research being conducted. And so far, the medical community is expecting positive outcomes with artificial disc replacement surgery.
Key Moments in the Episode
What is artificial disc replacement surgery 06:27
Incidence of sacroiliac joint pain after lumbar fusion surgery 12:06
What is an artificial disc 13:19
Artificial disc for the lumbar spine 17:18
Types of devices for low back versus neck 18:49
Exclusion criteria for artificial disc surgery 19:55
Positive outcomes for disc replacements in the neck and low back 21:30
Decrease in incidence of adjacent level disease with disc replacement surgery 22:35
Shelf-life of disc replacement devices 24:17
Lumbar facet joints 26:32
Dr. Dom's go-to health habits 30:13
Back Talk Doc is brought to you by Carolina Neurosurgery & Spine Associates, with offices in North and South Carolina. To learn more about Dr. Lakhia and treatment options for back and spine issues, go to backtalkdoc.com. To schedule an appointment with Carolina Neurosurgery & Spine Associates, you can call us at 1-800-344-6716 or visit our website at carolinaneurosurgery.com.
Intro: 00:01
Welcome. You're listening to Back Talk Doc, where you'll find answers to some of the most common questions about back pain and spine health brought to you by Carolina Neurosurgery and Spine Associates, where providing personalized, highly skilled and compassionate spine care has been our specialty for over 75 years.
Intro: 00:22
Now, it's time to understand the cause of back pain and learn about options to get you back on track. Here's your Back Talk Doc, Dr. Sanjiv Lakhia.
Dr. Sanjiv Lakhia: 00:35
The idea of joint replacement surgery is not an uncommon topic in the world today. If you're listening today to this episode, you probably know someone yourself who may or may not have had a knee replacement or a hip replacement done, but are you aware that joint replacements can apply as well to the spine? The topic is spinal arthroplasty and today's guest, Dr. Dom Coric, is a regional, if not a national or even an international, expert in the topic of disc replacement and joint replacement surgery in the neck and low back.
Dr. Sanjiv Lakhia: 01:15
I'm really excited to have Dr. Coric to the show. Dom, welcome to the show today.
Dr. Dom Coric: 01:20
Thanks, Sanjiv. I really appreciate it. Thanks for the kind introduction.
Dr. Sanjiv Lakhia: 01:23
Sure. Now I want to give the listeners a little bit of background and information with regards to who you are, and I appreciate you sending me your information. When I went to print off your CV I thought I had maybe triple clicked because the pages just wouldn't stop coming out of the printer, but it is true that it's almost probably 60 pages worth of career accomplishments, and I know you're not done, but some highlights for our listeners today.
Dr. Sanjiv Lakhia: 01:48
Dr. Coric obtained his medical degree from Wake Forest University Baptist Medical Center, School of Medicine there. Prior to that, he was a Dukie, graduate of Duke University for his undergrad. Dr. Coric ended up doing his general surgical and neurosurgical residency at Wake Forest University Baptist Medical Center, and has just an unbelievable list of accomplishments in the field of spine care and neurosurgery.
Dr. Sanjiv Lakhia: 02:16
Currently though, he's the Chairman Elect of the American Association for Neurological Surgery and the Congress of Neurological Surgeons. He is the President Elect of the International Society for the Advancement of Spine Surgery. And he actively is on the Executive Board of the Musculoskeletal Institute at Atrium Healthcare, here in Charlotte, North Carolina. A Division Director for the Spine Department for the Institute as well. Just has numerous committee roles, board memberships, executive board memberships. At Carolina Neurosurgery and Spine Associates, he's been practicing spine care since 1998, with a focus on spine trauma, minimal invasive spine surgery, complex spine surgery, and has become our go to expert on the idea of artificial disc replacement surgery.
Dr. Sanjiv Lakhia: 03:10
Dom, did I leave anything out that you want the listeners to know about your background?
Dr. Dom Coric: 03:14
That's quite enough. I think if we haven't put them asleep already, we can start talking about some clinical stuff, but I appreciate it.
Dr. Sanjiv Lakhia: 03:22
Yeah, absolutely. Before we dive into today's topic, which is the artificial discs and whatever you want to discuss around that, can you give the listeners just a brief review of your path, from how you got into the field of neurosurgery and maybe even what took you into some of the research path that you've been involved with?
Dr. Dom Coric: 03:42
I think that's a great entry point at the end of the day. As you know, when we come out of residency and you start operating, you end up doing... You're taking your chosen path. For me, even though I'm a neurosurgeon, my chosen path was to specialize in spine surgery.
Dr. Dom Coric: 03:58
As you know, I still, even though I'm Chief of Department at Carolinas Medical Center, I really don't do any elective brain surgery. I still do the trauma on call, but my elective practice is 100% spine. That's something that I gravitated to almost immediately outside of residency. As part of that, ended up doing a lot of the what we call complex spine work here.
Dr. Dom Coric: 04:23
As you know, we're a busy medical center at Carolinas neurosurgery covering Carolinas Medical Center and the Atrium System, which is level one trauma center and has about 30 or 40 hospitals that feed into the main hospitals here in Charlotte.
Dr. Dom Coric: 04:38
Ended up doing a lot of complex work in terms of trauma and tumor and degenerative scoliosis work. At the end of the day, I was missing some of the more straightforward surgeries that people more commonly come in for as far as pinched nerve causing radiculopathy with pain, weakness, or numbness in the distribution of a nerve.
Dr. Dom Coric: 04:59
I was interested in keeping my finger on the pulse of dealing with patients with everyday problems, and it felt like one way to do that was to stay up-to-date with the outpatient surgery, things that could be done in the outpatient center, and things that were more on the cutting edge. That includes a lot of the research protocols that you touched upon. The artificial discs, the cervical spine artificial disc, and cervical arthroplasty that we do are almost completely done in the outpatient center now, but we've done some disc repair protocols where we try to repair the discs that are also done in the outpatient center.
Dr. Dom Coric: 05:36
It was a way for me to keep in touch with not only what was cutting edge technology, but at the same time, keep me in tune to every day spine problems that people have to deal with day in day out and good results that we can see with doing those types of surgeries.
Dr. Sanjiv Lakhia: 05:52
Yeah, that's terrific. I think that skillset is what builds up your demand and your long waiting list. Let's dive into today's topic today. I know you've given multiple grand rounds on this topic before, but our listener makeup is going to be maybe someone who is just dealing with back pain and just found out that they have a herniated disc versus a clear medical background. Can you, in a simplistic way, explain to our listeners just exactly what you mean when you talk about artificial disc replacement surgery?
Dr. Dom Coric: 06:27
Sure. Even to back up a little bit from that, I think to give us an even bigger view, overview, is there are two basic kinds of surgeries that we do that are on the spine. There's decompressive surgeries, where you remove a substance, whether that is a ruptured disc or a herniated disc or a protruding disc or a bone spur. You're removing a structural problem that is compressing the nerve. We call that decompressive surgery. You're removing something without putting any stability back into the spine. For a lot of common problems, you're able to do that. For your garden variety, everyday ruptured disc, you're able to go in and shave just the ruptured part of the disc off, or you're able to remove some bone to free up a nerve that's being pinched by a spur, and the spine can tolerate the removal of a certain amount of structural stability in order to free up the nerve. People do well with that. That's typically a smaller operation.
Dr. Dom Coric: 07:30
The bigger operations we do are the operations that include decompression as well as stabilization. Those are operations where you have to remove whatever is pinching on the nerve, but in the process of doing that, either the spine was structurally compromised beforehand, or you make them unstable afterwards by the amount of bone or disc or ligament or whatever you're removing in order to free up the nerve. In those situations, you typically have to put stability back in. The common way to do that over the past several decades has been to do what's called a fusion. It's the removal of the disc itself and to replace that with either packing what used to be the disc full of bone, or put a spacer, either metallic or plastic, spacer that is filled with bone or a protein or a bank bone, or a protein that stimulates bone to grow. Then you remove that offending disc, and then you fuse between the two adjacent vertebral bodies.
Dr. Dom Coric: 08:30
That operation has been around for a long time and it works very well, but the issue, it leaves you with two issues. One issue is, is that you'll lose the motion at the level of that one particular disc. If you're doing one disc loss of motion in either in the low back or the neck, isn't that much. In the neck, the loss of one disc would probably cost you somewhere about 8-10% of your motion, in the low back, it would probably cost you more about 15-17% of loss of motion. So it's not so much the loss of motion, it's the fact that by taking away a shock absorber and replacing it with bone and doing the fusion with rods and screws or plates, which are typically how we do fusions, you're actually putting the stress at the levels above and below the level that you fuse.
Dr. Dom Coric: 09:15
It's not necessarily loss of motion, per se. Most of us can tolerate a 10, 15, 20% loss of motion, but it's the fact that those stresses don't disappear, they go to the levels above and below and you see those other levels wearing out and potentially faster than they would normally wear out, so you see people doing well after a fusion for a period of time, whether that's three, five, seven, 10 years, but they come back with what we call adjacent level disease, where they've worn out another level and they have to undergo a second or potentially third operation.
Dr. Dom Coric: 09:48
That is especially relevant in people who were being operated on in their twenties or thirties or forties or even fifties, because you care what happens in five, 10, 15, 20, 30 years, as opposed to somebody, not that you don't care if you're in your seventies or eighties, but if you're going to get five or 10 good years at that point, you're probably pretty happy with your operation. Conversely, if you're 35 and you get five or 10 years, you're still in the prime of your working life.
Dr. Dom Coric: 10:13
People started to say, can we do better than just removing the disc and packing it full of bone, spacers, rod screws, plates, et cetera, and the idea of artificial discs came into spine surgery. I might add that it came into spine surgery a lot later than it came into orthopedic surgery for joints. There was a time, decades and decades ago, where if you had a problem with your ankle or knee or hip, you would fuse that joint. But it's been several decades since joint replacement surgery was introduced, so now most people would get an artificial hip or an artificial knee. It's almost unheard of to fuse a knee or a hip.
Dr. Dom Coric: 10:52
Having said that, the spine is a little bit different, so it's not an exact analogy, but the idea is that if you don't need to fuse that joint, if you don't need to completely, even if you do need to completely remove it, can you put something else back in that maintains the motion and doesn't put the stresses at the levels above and below?
Dr. Dom Coric: 11:11
That's how the concept of artificial joint replacement or artificial disc replacement or total disc replacement surgery was born in the spine. It started in Europe in the 1990s, the first FDA approvals for artificial discs in the United States in the low back, or lumbar spine, was in 2002-2003. The first artificial disc approvals for the cervical spine in the United States was in 2006.
Dr. Sanjiv Lakhia: 11:39
Wow. That's a really good overview about how we even come to the idea of why you would consider doing a disc replacement surgery. You just covered a lot there. Would that explain why, in some patients, if they have a big lumbar fusion surgery, that from a physiatry perspective, I tend to see a higher incidence of sacroiliac joint pain. Is it speak to just the distribution of the forces? They got to go somewhere.
Dr. Dom Coric: 12:06
That's exactly right, Sanjiv. That's point on. The bottom line is, is that the forces, the discs that have to be typically removed when you do a fusion surgery, and sometimes you just have to do that because of the underlying pathology, but those forces don't just disappear, they need to be redistributed.
Dr. Dom Coric: 12:24
Every time you take out a shock absorber, the adjacent shock absorbers above and below have to work a little bit harder. In the case of SI joint that's a great example, because a lot of times when you do multilevel fusion surgery in the low back, there are significant stresses that need to be redistributed, and where they typically go, if you fuse down to five one, which is, as you know, the last disc in your back, that is going to be transferred to the SI joint and those increased stresses can cause SI joint dysfunction. It is not uncommon after multilevel lumbar fusion operation.
Dr. Sanjiv Lakhia: 12:59
If you get into the point where you're thinking about an artificial disc and a patient wants to know, well, what is an artificial disc? What's it made out of? Is it similar to a regular disc that we say has a soft inner core that helps distribute the forces? Can you give people a general idea about what you would actually be putting in their spine?
Dr. Dom Coric: 13:19
That's a great question, Sanjiv, because that is something that is, like we talked about, the lumbar FDA approvals came in early 2000, 2002 and the cervical later, in the 2000, 2006. So this has really only been going on, in the United States anyway, for about 15, 20 years and not quite, so it's a fast evolving technology. Fusion technologies evolve, but they've evolved a little bit slower and a little bit more incrementally. But we see with artificial discs that the first artificial disc that was FDA approved in the United States in the lumbar spine was the Charite artificial disc, and that one is completely obsolete in the fact that it's no longer actually made.
Dr. Dom Coric: 14:00
You see over a period of five, 10 years, you see a big change in these artificial discs. In the cervical spine, there are currently eight FDA approved devices for one or two level cervical artificial disc replacement, and out of those devices, I would say a good solid three or four of them have essentially become obsolete.
Dr. Dom Coric: 14:20
You see a big change over these past 10 or 15 years in the makeup of these devices in terms of their biomaterials. I'll use that as an example. Early on, it was thought that maybe you would need to have metal on metal artificial disc in the cervical spine, like you see with the total joints, the hips and the knees, and they were felt to be more robust. Then it was seen that you didn't need that robust nature for an artificial disc in the neck, because it really only saw the stresses of carrying the head as opposed to carrying the whole body that a hip or knee would see.
Dr. Dom Coric: 14:54
Even though a bunch of them started out as metal on metal devices, you don't really see the metal on metal anymore. A lot of the devices started out with harder metals, metal like cobalt chrome, and those metals through a lot of artifacts so you could get an MRI, but you couldn't see almost your visualization at the site of the artificial disc. The adjacent levels was almost totally obscured by the metallic artifact you can get with an MRI. Even with CT scans, you didn't get a great view.
Dr. Dom Coric: 15:25
Then you saw a move towards more biomaterials that were more friendly with MRIs and with CT scans. You saw a movement from metal on metal devices to metal on polymer devices, and those polymers are typically polyurethane or polyethylene, which are basically hard plastic devices. You saw a movement, even the latest devices include hard plastic like polyether ether ketone, which is also called PEEK, which is a hard plastic device that has very little, if any, artifact on an MRI or a CT scan.
Dr. Dom Coric: 16:00
You've seen this evolution of the biomaterials. Along with that, you've seen this evolution for devices that were just basically ball and socket devices at the beginning that maintained motion but did not have an ability to move with the spine. Then you had devices that had what we call mobile cores and had an ability to move with the spine. Then you have devices that have some area of compressibility. Some of the newer devices allow for some compressibility as well.
Dr. Dom Coric: 16:28
You go from having a device that is simple ball and socket, to one that has a mobile core, to one that has a compressible and mobile core. You've seen this evolution occur very quickly over a period of five, 10, 15 years. The newer devices really have some distinct advantages to some of the devices that have been on the market for a longer period of time.
Dr. Sanjiv Lakhia: 16:48
Sounds like a biomedical engineer's dream to try and come up with the best device from a physics perspective and a stress and strain perspective.
Dr. Dom Coric: 16:58
Well, it is a fertile area for biomechanics and biomaterials. I think you really have seen a relatively rapid evolution of these devices over a period of time, like we've talked about.
Dr. Sanjiv Lakhia: 17:10
Currently in the United States, a patient can get an artificial disc for the cervical spine. Can they get one for the lumbar spine?
Dr. Dom Coric: 17:18
Even though the lumbar spine FDA approvals came earlier, the adoption of artificial discs in the lumbar spine has happened a lot more slowly, and a lot of that had to do with insurance coverage. A lot of the insurance coverage had to do with what you were operating on. In other words, in the lumbar spine, the primary indication for replacing a bad disc is mechanical low back pain. In the cervical spine, the number one indication is radiating arm pain, so a disc that is protruding and pinching on a nerve.
Dr. Dom Coric: 17:51
In the cervical spine, you have to remove the disc to get to the part of the nerve that's being pinched, so instead of doing a fusion, you put in an artificial disc. So really what you're operating on is a pinched nerve in the neck by and large, wherein in the lumbar spine, you're operating on more mechanical or axial back pain.
Dr. Dom Coric: 18:07
That's a long winded answer to your question, but the answer to the question is that the insurance approval in lumbar spine has been slower, so it hasn't caught on as quickly. But there are currently two FDA approved devices for lumbar spine surgery. You're seeing more and more of that adopted as time has gone on. We've seen more evidence basis, more studies that have come out to show that it really does have some positive attributes.
Dr. Sanjiv Lakhia: 18:35
I'd imagine that the options for low back versus neck in terms of the prosthetic or the disc itself, these are going to be different because of the different forces across the regions, or do you use the same types of implants or products?
Dr. Dom Coric: 18:49
They're similar, but I wouldn't say they're the same. Like we talked about with the neck, the biomechanical forces that are being carried are basically the forces of carrying the head around, whereas the low back you have to carry the torso and the rest of the body to some degree, so they have to be larger and more robust because of the anatomic constraints of your neck versus your low back.
Dr. Dom Coric: 19:09
But having said that, in a lot of ways, the neck versions are a little bit smaller versions of the lumbar versions at least to begin with, but they've become more sophisticated in the neck because of the faster and more widespread adoption that we've seen with neck artificial discs. Like I said, there are two FDA approvals for the lumbar spine, where there are eight FDA approvals for the cervical spine for one and two level. There are some differences there.
Dr. Sanjiv Lakhia: 19:38
Are there disqualifiers? If a patient comes to me and says, "Hey, I want to get an opinion about an artificial disc, but I had surgery on my disc five years ago." Are there things that would disqualify a patient from being a candidate for consideration, let's say in the cervical, spine for this type of surgery?
Dr. Dom Coric: 19:55
Yes. That's a great question. The answer is there are exclusion criteria and in fact, that's why there's still a lot more fusions done then artificial discs, because artificial discs have a much more stringent inclusion criteria, basically it's for younger, healthier looking discs that already don't have a lot of wear and tear changes, or what we call spondylosis.
Dr. Dom Coric: 20:18
The disc has to be the primary culprit, the joints in the back called the facet joints, you can't have a lot of wear and tear in those because, again, the artificial disc or total disc replacement is what it sounds like, you take out the disc, but that's all you take out and you put an artificial disc, so you're still dependent on the facet joints from the back and artificial disc are FDA approved for one or two levels in the neck. So for people with multiple levels, three, four, five levels, that's typically considered an exclusion criteria. People who have deformities of their spine in terms of scoliosis or kyphosis typically aren't addressed with artificial discs. Artificial discs are really for more focal one or two level problems in a younger, healthier population.
Dr. Sanjiv Lakhia: 21:04
That's a very good clarification there. If someone's listening and they're sitting there wondering, hey, could I benefit from this? I think those are some good questions to ask yourself.
Dr. Sanjiv Lakhia: 21:13
As we look at the difference between the cervical and lumbar, I think you've touched on quite a bit of this, do you see the same type of results in terms of positive outcomes for patients that get disc replacements, whether it's in the neck or low back?
Dr. Dom Coric: 21:30
No. I would say that the success in the low back isn't quite as high as it is for the neck. That has to do, again, exactly what we were talking about previously. Typically, people have a pinched nerve and that's what you're operating on in the neck. Typically speaking, if you're able to free up that nerve, about 90% of people will show really very positive results. When you're operating on people who have primarily back pain, axial back pain, in other words, the more I do the more my back hurts, It has been my experience that more respond in the 70% category. Literature would suggest anywhere from 50-70%. I would say that my own personal results are more in the 60-70% for low back and more in the 90% range for the neck. But that has to do, again, with the bottom line of what it is that you're operating on.
Dr. Sanjiv Lakhia: 22:23
In the cervical spine, are you seeing a decrease in the incidence of the adjacent level issue that you might encounter with cervical fusion surgery?
Dr. Dom Coric: 22:35
I got to tell you that, Sanjiv, that's a loaded question, because that is something we could spend a lot of time talking about it in a fairly sophisticated fashion, as far as what the literature would show. The short answer is that the rate of people wearing out an adjacent level after cervical surgery is so low, it's probably only about 1 or maybe 2%, that in order for you to really show those results, you either have to do a study that has literally thousands of patients, or you have to do a study that follows those hundreds of patients for five, 10, 15 years.
Dr. Dom Coric: 23:11
Like we talked about earlier, we're just now starting to get some of that long-term followup. I would tell you that the jury is still out, but I've seen enough positive evidence once with the long-term followup that I would say that it does have an impact. I wouldn't say that there's an evidence basis to say definitively that it 100% decreases the rate of adjacent level disease, I would say that there is enough evidence to point in that direction, but that jury will come back as more evidence comes out, as we get longer term follow up from some of these early studies.
Dr. Sanjiv Lakhia: 23:45
All right. Two more questions I want to hit you with on this topic, and then I'll let you talk about some of the work you're done with the facet joints. I've had these questions from my patients several times, and I didn't really know the answer, so I want to get it from you today. Let's say you're in your forties, you go in, someone sees you, and they get an artificial disc done for a cervical radiculopathy. They're doing great. They want to know, how long is it going to last? For example, in the orthopedic world, you'll hear 10 to 15 years for a total knee or total hip. Is there a shelf life on these products for the cervical spine?
Dr. Dom Coric: 24:17
We have the answer to that, and the answer is that there really is not a shelf life. The idea there is that these things are designed to last the rest of people's lives. Having said that, if you're getting an operation in your twenties or thirties, the rest of your life could be 50, 60, 70 years, and the discs haven't been long enough for us to know that definitively. But the idea is that they won't wear out in a predetermined period of time.
Dr. Dom Coric: 24:44
Having said that, there are multiple factors that can affect the wear of the disc, such as what it is made of, how it was placed, what kind of work or life people are going back to. But the idea, like you said, with hip, or at least early on with hip replacement surgery, was wait as long as you can, because we know you're going to need another one in 10 or 12 years. That's not really the case anymore. There's a longer shelf life. That was certainly what people said as early as five or 10 years ago with artificial hips and knees to some degree.
Dr. Dom Coric: 25:16
We're not saying that we go in with the idea that it would last 30, 40, 50 years, that's based on some of the biomechanical testing that is done, where they cycle these things biomechanically for a million cycles. A million cycles are considered to be more or less equivalent to a year of life, and so they'll cycle them to 20, 30, 40 million cycles and then the idea is, well, maybe this would last 20, 30, 40, 50 years. That's the idea, but like I said, they haven't been around long enough for us to know that for sure.
Dr. Sanjiv Lakhia: 25:45
That's fascinating though, that they put it to the test, so to speak. I think for me, it makes sense from a... I have an engineering background and it just makes sense cervical discs should outlast a total knee from a weightbearing perspective, although there's more degrees of freedom in the neck, certainly. But I think if you take care of yourself, you don't get into major trauma or issues, sounds like you'd you be a good shape after having that done.
Dr. Dom Coric: 26:08
I would agree with that. I think that you're exactly right. You're just not seeing the same stress load that you would see with an artificial hip or an artificial knee.
Dr. Sanjiv Lakhia: 26:19
Do you want to pivot a little bit? You talked before about the importance of the facet joints as being part of the whole vertebral body just complex. Talk to the listeners a little bit about some of the research you're involved with as it pertains to the lumbar facet joints.
Dr. Dom Coric: 26:32
Sure. Like we talked about, there are FDA approvals for lumbar artificial disc and cervical artificial discs, and to even take a step back from that, like you just explained, the spine really is a three joint complex. There is a disc in the front and there's two facet joints in the back, one on each side. That's three joint complex, one disc and two facet joints.
Dr. Dom Coric: 26:56
When you do an artificial disc, you have to make sure that the disc is the pain generator, the disc is the pathological part of the spine, but that the facets are in good shape. When you do a fusion, you don't have to do that because typically when you do a fusion, you stop the motion completely at that level, so whether it's coming from the disc or the facet joints is irrelevant because you're shutting the whole segment down.
Dr. Dom Coric: 27:20
With artificial discs, it's super important that you're able to just focus in on a bad disc itself, as opposed to the disc and the joint, the facet joint in the back. Now, when you do, conversely, people come in, they have good discs, but bad facet joints, and so you say, okay, we've got to take out the facet joint, but do we necessarily have to do a fusion because the disc is not that bad? The idea there is, take out the bad facet joints and then replace it. Instead of doing a fusion, you would replace it with an artificial facet.
Dr. Dom Coric: 27:53
There are no FDA approvals for that. There have been several devices that have been in study over the past two decades, including one that is currently an active study right now, and that's called the TOPS artificial facet. That is an operation where, instead of, like we talked about with lumbar artificial discs you're operating on people who have primarily low back pain, with lumbar facet replacement you're operating on people who have primarily leg pain and some element of back pain, and they have bad joints and those bad joints have resulted in stenosis and spondylolisthesis.
Dr. Dom Coric: 28:30
As you know, stenosis is narrowing where the spinal nerves are and spondylolisthesis is a slippage of one vertebral body on the next. I'm really excited about this technology because it is focusing on the cervical arthroplasty, cervical artificial disc focus on nerve pain, this is more of a procedure that focuses on nerve pain.
Dr. Dom Coric: 28:53
Also, additionally, the lumbar artificial disc have to be taken out from the front. You have to do what's called an anterior approach, which is a less common approach to the spine. Whereas the lumbar artificial facet is taken from the back, which is more of a traditional standard low back midline operation, where you go, we remove the bone, put in rods, and then instead of connecting those rods to... I'm sorry, put in screws, and instead of connecting those screws to rigid rods that don't move, which is a fusion, you connect those screws to a flexible device that maintains the motion and essentially replaces the facet.
Dr. Sanjiv Lakhia: 29:31
That's amazing. I think the take home point here is that there's a lot of cutting-edge research being done and you're on the forefront of it and our group in general. If you're out struggling and you're listening to the podcast today, feel free to reach out to us and see what can be appropriate for you.
Dr. Sanjiv Lakhia: 29:49
Dom, unless you had anything else you want to add on artificial discs I want to close the episode with just a couple of questions about your personal health habits. I always like to pick the brain of the people I interview.
Dr. Sanjiv Lakhia: 29:59
You're a giant in the field of neurosurgery. You work from sun-up to sun-down. You've been doing it for decades now. What have been your go to health habits to keep you functioning at such a high level?
Dr. Dom Coric: 30:13
Well, that's very kind of you to say, Sanjiv. Having said that, like you said, there's nothing magical about it. I think there are things that we all know we should do, which is first and foremost have some kind of work/life balance. Everyone understands that we like to think that what we're doing is important, we're helping people. But having said that, you can't help other people if you yourself are not of sound mind and body. One way to do that is to put perspective that you have a family and you have to have that work/life balance. You have to enjoy doing things with your family. You have to just put work aside and deal with family on a regular basis to have that balance.
Dr. Dom Coric: 30:51
Because you're familiar, and I think most of the people in the medical field are familiar with it, you can't do what you do without a support system. At the office, that support system, you're going to have an administrative assistant, you're going to have a mid level provider, you're going to have a nurse, you're going to have a nurse assistant. People who allow you to do what you can do. The same thing goes in your personal life. You can't do what you do if you don't have a wife or a family that supports you, or significant other. That is super important.
Dr. Dom Coric: 31:20
I'd say first and foremost, you have to be able to strike that balance. I think as a young doctor, that is especially hard because you feel like you have to earn your reputation, but as time goes on, you begin to realize that it's just not sustainable unless you're having relationships with family and friends, the people around you that make my life meaningful to you. I think that's first and foremost.
Dr. Dom Coric: 31:40
The second thing that I think you have to do is some form of regular physical exercise. It doesn't mean that everyone has to run a marathon or a triathlon, but you have to cut out an hour or two of exercise a day for at least three or four days a week. And like you exercise your body, I think you have to exercise your brain.
Dr. Dom Coric: 32:01
One of the things that I stopped doing once I started my residency and I was in early doc, I became functionally illiterate. I just basically stopped reading as something that was an enjoyable thing. I would only read medical literature, things that were relevant to what I was doing. And that, to me, was a big mistake.
Dr. Dom Coric: 32:19
One of our older partners here, Jerry Petty, is the one who got me back into reading as an educational tool and as a mental exercise and to read for pleasure again. Now I'm back to being at least somewhat literate in things that are not directly related to medicine. I think that that's important.
Dr. Dom Coric: 32:37
If I had to rank it, the three things I would say that give me sanity in my life are family and friends, number one, number two, an ability to have physical exercise and to do whatever is sustainable, three to four days a week minimum, and then to have some sort of mental exercise that is away from medicine, that has to do with just reading or being involved with some other activity besides medical activities.
Dr. Sanjiv Lakhia: 33:03
I really love that response. I've had Joe Cheedle on the show and Mark Smith and Tony Asher, and each one of them have answered that question differently. Mark, he also talked about the importance of exercise as his stress outlet, and Joe is really big into exercise. I don't know how the guy finds the time, but he's into marathons and Orangetheory, and he's got a special diet he's on. And then Tony talked a little bit about spirituality.
Dr. Sanjiv Lakhia: 33:32
But bringing up the idea of the family and support network, I think that's fantastic. It's important, I think, for listeners to understand that there's other sides to us as practicing physicians and the fact that we take the time to nurture that side makes us better doctors in the long run.
Dr. Sanjiv Lakhia: 33:48
I know that was some personal questions. I really appreciate you sharing that with our listeners today. I think overall I really enjoyed this interview, Dom. I learned a ton. I feel better equipped myself to answer some of these questions that my patients have. I'm certain that those who download the episode and take a listen to it, might find a new path forward. I want to thank you so much for your time today.
Dr. Dom Coric: 34:10
Thank you, Sanjiv. Thanks for having me. I really enjoyed it. Appreciate it.
Dr. Sanjiv Lakhia: 34:13
Absolutely.
Outro: 34:16
Thank you for listening to this episode of Back Talk Doc, brought to you by Carolina Neurosurgery and Spine Associates, with offices in North and South Carolina. If you'd like to learn more about Dr. Lakhia and treatment options for back issues, go to backtalkdoc.com. We look forward to having you join us for more insights about back pain and spine health on the next episode of Back Talk Doc. Additional information is also available at carolinaneurosurgery.com.
Welcome. You're listening to Back Talk Doc, where you'll find answers to some of the most common questions about back pain and spine health brought to you by Carolina Neurosurgery and Spine Associates, where providing personalized, highly skilled and compassionate spine care has been our specialty for over 75 years.
Intro: 00:22
Now, it's time to understand the cause of back pain and learn about options to get you back on track. Here's your Back Talk Doc, Dr. Sanjiv Lakhia.
Dr. Sanjiv Lakhia: 00:35
The idea of joint replacement surgery is not an uncommon topic in the world today. If you're listening today to this episode, you probably know someone yourself who may or may not have had a knee replacement or a hip replacement done, but are you aware that joint replacements can apply as well to the spine? The topic is spinal arthroplasty and today's guest, Dr. Dom Coric, is a regional, if not a national or even an international, expert in the topic of disc replacement and joint replacement surgery in the neck and low back.
Dr. Sanjiv Lakhia: 01:15
I'm really excited to have Dr. Coric to the show. Dom, welcome to the show today.
Dr. Dom Coric: 01:20
Thanks, Sanjiv. I really appreciate it. Thanks for the kind introduction.
Dr. Sanjiv Lakhia: 01:23
Sure. Now I want to give the listeners a little bit of background and information with regards to who you are, and I appreciate you sending me your information. When I went to print off your CV I thought I had maybe triple clicked because the pages just wouldn't stop coming out of the printer, but it is true that it's almost probably 60 pages worth of career accomplishments, and I know you're not done, but some highlights for our listeners today.
Dr. Sanjiv Lakhia: 01:48
Dr. Coric obtained his medical degree from Wake Forest University Baptist Medical Center, School of Medicine there. Prior to that, he was a Dukie, graduate of Duke University for his undergrad. Dr. Coric ended up doing his general surgical and neurosurgical residency at Wake Forest University Baptist Medical Center, and has just an unbelievable list of accomplishments in the field of spine care and neurosurgery.
Dr. Sanjiv Lakhia: 02:16
Currently though, he's the Chairman Elect of the American Association for Neurological Surgery and the Congress of Neurological Surgeons. He is the President Elect of the International Society for the Advancement of Spine Surgery. And he actively is on the Executive Board of the Musculoskeletal Institute at Atrium Healthcare, here in Charlotte, North Carolina. A Division Director for the Spine Department for the Institute as well. Just has numerous committee roles, board memberships, executive board memberships. At Carolina Neurosurgery and Spine Associates, he's been practicing spine care since 1998, with a focus on spine trauma, minimal invasive spine surgery, complex spine surgery, and has become our go to expert on the idea of artificial disc replacement surgery.
Dr. Sanjiv Lakhia: 03:10
Dom, did I leave anything out that you want the listeners to know about your background?
Dr. Dom Coric: 03:14
That's quite enough. I think if we haven't put them asleep already, we can start talking about some clinical stuff, but I appreciate it.
Dr. Sanjiv Lakhia: 03:22
Yeah, absolutely. Before we dive into today's topic, which is the artificial discs and whatever you want to discuss around that, can you give the listeners just a brief review of your path, from how you got into the field of neurosurgery and maybe even what took you into some of the research path that you've been involved with?
Dr. Dom Coric: 03:42
I think that's a great entry point at the end of the day. As you know, when we come out of residency and you start operating, you end up doing... You're taking your chosen path. For me, even though I'm a neurosurgeon, my chosen path was to specialize in spine surgery.
Dr. Dom Coric: 03:58
As you know, I still, even though I'm Chief of Department at Carolinas Medical Center, I really don't do any elective brain surgery. I still do the trauma on call, but my elective practice is 100% spine. That's something that I gravitated to almost immediately outside of residency. As part of that, ended up doing a lot of the what we call complex spine work here.
Dr. Dom Coric: 04:23
As you know, we're a busy medical center at Carolinas neurosurgery covering Carolinas Medical Center and the Atrium System, which is level one trauma center and has about 30 or 40 hospitals that feed into the main hospitals here in Charlotte.
Dr. Dom Coric: 04:38
Ended up doing a lot of complex work in terms of trauma and tumor and degenerative scoliosis work. At the end of the day, I was missing some of the more straightforward surgeries that people more commonly come in for as far as pinched nerve causing radiculopathy with pain, weakness, or numbness in the distribution of a nerve.
Dr. Dom Coric: 04:59
I was interested in keeping my finger on the pulse of dealing with patients with everyday problems, and it felt like one way to do that was to stay up-to-date with the outpatient surgery, things that could be done in the outpatient center, and things that were more on the cutting edge. That includes a lot of the research protocols that you touched upon. The artificial discs, the cervical spine artificial disc, and cervical arthroplasty that we do are almost completely done in the outpatient center now, but we've done some disc repair protocols where we try to repair the discs that are also done in the outpatient center.
Dr. Dom Coric: 05:36
It was a way for me to keep in touch with not only what was cutting edge technology, but at the same time, keep me in tune to every day spine problems that people have to deal with day in day out and good results that we can see with doing those types of surgeries.
Dr. Sanjiv Lakhia: 05:52
Yeah, that's terrific. I think that skillset is what builds up your demand and your long waiting list. Let's dive into today's topic today. I know you've given multiple grand rounds on this topic before, but our listener makeup is going to be maybe someone who is just dealing with back pain and just found out that they have a herniated disc versus a clear medical background. Can you, in a simplistic way, explain to our listeners just exactly what you mean when you talk about artificial disc replacement surgery?
Dr. Dom Coric: 06:27
Sure. Even to back up a little bit from that, I think to give us an even bigger view, overview, is there are two basic kinds of surgeries that we do that are on the spine. There's decompressive surgeries, where you remove a substance, whether that is a ruptured disc or a herniated disc or a protruding disc or a bone spur. You're removing a structural problem that is compressing the nerve. We call that decompressive surgery. You're removing something without putting any stability back into the spine. For a lot of common problems, you're able to do that. For your garden variety, everyday ruptured disc, you're able to go in and shave just the ruptured part of the disc off, or you're able to remove some bone to free up a nerve that's being pinched by a spur, and the spine can tolerate the removal of a certain amount of structural stability in order to free up the nerve. People do well with that. That's typically a smaller operation.
Dr. Dom Coric: 07:30
The bigger operations we do are the operations that include decompression as well as stabilization. Those are operations where you have to remove whatever is pinching on the nerve, but in the process of doing that, either the spine was structurally compromised beforehand, or you make them unstable afterwards by the amount of bone or disc or ligament or whatever you're removing in order to free up the nerve. In those situations, you typically have to put stability back in. The common way to do that over the past several decades has been to do what's called a fusion. It's the removal of the disc itself and to replace that with either packing what used to be the disc full of bone, or put a spacer, either metallic or plastic, spacer that is filled with bone or a protein or a bank bone, or a protein that stimulates bone to grow. Then you remove that offending disc, and then you fuse between the two adjacent vertebral bodies.
Dr. Dom Coric: 08:30
That operation has been around for a long time and it works very well, but the issue, it leaves you with two issues. One issue is, is that you'll lose the motion at the level of that one particular disc. If you're doing one disc loss of motion in either in the low back or the neck, isn't that much. In the neck, the loss of one disc would probably cost you somewhere about 8-10% of your motion, in the low back, it would probably cost you more about 15-17% of loss of motion. So it's not so much the loss of motion, it's the fact that by taking away a shock absorber and replacing it with bone and doing the fusion with rods and screws or plates, which are typically how we do fusions, you're actually putting the stress at the levels above and below the level that you fuse.
Dr. Dom Coric: 09:15
It's not necessarily loss of motion, per se. Most of us can tolerate a 10, 15, 20% loss of motion, but it's the fact that those stresses don't disappear, they go to the levels above and below and you see those other levels wearing out and potentially faster than they would normally wear out, so you see people doing well after a fusion for a period of time, whether that's three, five, seven, 10 years, but they come back with what we call adjacent level disease, where they've worn out another level and they have to undergo a second or potentially third operation.
Dr. Dom Coric: 09:48
That is especially relevant in people who were being operated on in their twenties or thirties or forties or even fifties, because you care what happens in five, 10, 15, 20, 30 years, as opposed to somebody, not that you don't care if you're in your seventies or eighties, but if you're going to get five or 10 good years at that point, you're probably pretty happy with your operation. Conversely, if you're 35 and you get five or 10 years, you're still in the prime of your working life.
Dr. Dom Coric: 10:13
People started to say, can we do better than just removing the disc and packing it full of bone, spacers, rod screws, plates, et cetera, and the idea of artificial discs came into spine surgery. I might add that it came into spine surgery a lot later than it came into orthopedic surgery for joints. There was a time, decades and decades ago, where if you had a problem with your ankle or knee or hip, you would fuse that joint. But it's been several decades since joint replacement surgery was introduced, so now most people would get an artificial hip or an artificial knee. It's almost unheard of to fuse a knee or a hip.
Dr. Dom Coric: 10:52
Having said that, the spine is a little bit different, so it's not an exact analogy, but the idea is that if you don't need to fuse that joint, if you don't need to completely, even if you do need to completely remove it, can you put something else back in that maintains the motion and doesn't put the stresses at the levels above and below?
Dr. Dom Coric: 11:11
That's how the concept of artificial joint replacement or artificial disc replacement or total disc replacement surgery was born in the spine. It started in Europe in the 1990s, the first FDA approvals for artificial discs in the United States in the low back, or lumbar spine, was in 2002-2003. The first artificial disc approvals for the cervical spine in the United States was in 2006.
Dr. Sanjiv Lakhia: 11:39
Wow. That's a really good overview about how we even come to the idea of why you would consider doing a disc replacement surgery. You just covered a lot there. Would that explain why, in some patients, if they have a big lumbar fusion surgery, that from a physiatry perspective, I tend to see a higher incidence of sacroiliac joint pain. Is it speak to just the distribution of the forces? They got to go somewhere.
Dr. Dom Coric: 12:06
That's exactly right, Sanjiv. That's point on. The bottom line is, is that the forces, the discs that have to be typically removed when you do a fusion surgery, and sometimes you just have to do that because of the underlying pathology, but those forces don't just disappear, they need to be redistributed.
Dr. Dom Coric: 12:24
Every time you take out a shock absorber, the adjacent shock absorbers above and below have to work a little bit harder. In the case of SI joint that's a great example, because a lot of times when you do multilevel fusion surgery in the low back, there are significant stresses that need to be redistributed, and where they typically go, if you fuse down to five one, which is, as you know, the last disc in your back, that is going to be transferred to the SI joint and those increased stresses can cause SI joint dysfunction. It is not uncommon after multilevel lumbar fusion operation.
Dr. Sanjiv Lakhia: 12:59
If you get into the point where you're thinking about an artificial disc and a patient wants to know, well, what is an artificial disc? What's it made out of? Is it similar to a regular disc that we say has a soft inner core that helps distribute the forces? Can you give people a general idea about what you would actually be putting in their spine?
Dr. Dom Coric: 13:19
That's a great question, Sanjiv, because that is something that is, like we talked about, the lumbar FDA approvals came in early 2000, 2002 and the cervical later, in the 2000, 2006. So this has really only been going on, in the United States anyway, for about 15, 20 years and not quite, so it's a fast evolving technology. Fusion technologies evolve, but they've evolved a little bit slower and a little bit more incrementally. But we see with artificial discs that the first artificial disc that was FDA approved in the United States in the lumbar spine was the Charite artificial disc, and that one is completely obsolete in the fact that it's no longer actually made.
Dr. Dom Coric: 14:00
You see over a period of five, 10 years, you see a big change in these artificial discs. In the cervical spine, there are currently eight FDA approved devices for one or two level cervical artificial disc replacement, and out of those devices, I would say a good solid three or four of them have essentially become obsolete.
Dr. Dom Coric: 14:20
You see a big change over these past 10 or 15 years in the makeup of these devices in terms of their biomaterials. I'll use that as an example. Early on, it was thought that maybe you would need to have metal on metal artificial disc in the cervical spine, like you see with the total joints, the hips and the knees, and they were felt to be more robust. Then it was seen that you didn't need that robust nature for an artificial disc in the neck, because it really only saw the stresses of carrying the head as opposed to carrying the whole body that a hip or knee would see.
Dr. Dom Coric: 14:54
Even though a bunch of them started out as metal on metal devices, you don't really see the metal on metal anymore. A lot of the devices started out with harder metals, metal like cobalt chrome, and those metals through a lot of artifacts so you could get an MRI, but you couldn't see almost your visualization at the site of the artificial disc. The adjacent levels was almost totally obscured by the metallic artifact you can get with an MRI. Even with CT scans, you didn't get a great view.
Dr. Dom Coric: 15:25
Then you saw a move towards more biomaterials that were more friendly with MRIs and with CT scans. You saw a movement from metal on metal devices to metal on polymer devices, and those polymers are typically polyurethane or polyethylene, which are basically hard plastic devices. You saw a movement, even the latest devices include hard plastic like polyether ether ketone, which is also called PEEK, which is a hard plastic device that has very little, if any, artifact on an MRI or a CT scan.
Dr. Dom Coric: 16:00
You've seen this evolution of the biomaterials. Along with that, you've seen this evolution for devices that were just basically ball and socket devices at the beginning that maintained motion but did not have an ability to move with the spine. Then you had devices that had what we call mobile cores and had an ability to move with the spine. Then you have devices that have some area of compressibility. Some of the newer devices allow for some compressibility as well.
Dr. Dom Coric: 16:28
You go from having a device that is simple ball and socket, to one that has a mobile core, to one that has a compressible and mobile core. You've seen this evolution occur very quickly over a period of five, 10, 15 years. The newer devices really have some distinct advantages to some of the devices that have been on the market for a longer period of time.
Dr. Sanjiv Lakhia: 16:48
Sounds like a biomedical engineer's dream to try and come up with the best device from a physics perspective and a stress and strain perspective.
Dr. Dom Coric: 16:58
Well, it is a fertile area for biomechanics and biomaterials. I think you really have seen a relatively rapid evolution of these devices over a period of time, like we've talked about.
Dr. Sanjiv Lakhia: 17:10
Currently in the United States, a patient can get an artificial disc for the cervical spine. Can they get one for the lumbar spine?
Dr. Dom Coric: 17:18
Even though the lumbar spine FDA approvals came earlier, the adoption of artificial discs in the lumbar spine has happened a lot more slowly, and a lot of that had to do with insurance coverage. A lot of the insurance coverage had to do with what you were operating on. In other words, in the lumbar spine, the primary indication for replacing a bad disc is mechanical low back pain. In the cervical spine, the number one indication is radiating arm pain, so a disc that is protruding and pinching on a nerve.
Dr. Dom Coric: 17:51
In the cervical spine, you have to remove the disc to get to the part of the nerve that's being pinched, so instead of doing a fusion, you put in an artificial disc. So really what you're operating on is a pinched nerve in the neck by and large, wherein in the lumbar spine, you're operating on more mechanical or axial back pain.
Dr. Dom Coric: 18:07
That's a long winded answer to your question, but the answer to the question is that the insurance approval in lumbar spine has been slower, so it hasn't caught on as quickly. But there are currently two FDA approved devices for lumbar spine surgery. You're seeing more and more of that adopted as time has gone on. We've seen more evidence basis, more studies that have come out to show that it really does have some positive attributes.
Dr. Sanjiv Lakhia: 18:35
I'd imagine that the options for low back versus neck in terms of the prosthetic or the disc itself, these are going to be different because of the different forces across the regions, or do you use the same types of implants or products?
Dr. Dom Coric: 18:49
They're similar, but I wouldn't say they're the same. Like we talked about with the neck, the biomechanical forces that are being carried are basically the forces of carrying the head around, whereas the low back you have to carry the torso and the rest of the body to some degree, so they have to be larger and more robust because of the anatomic constraints of your neck versus your low back.
Dr. Dom Coric: 19:09
But having said that, in a lot of ways, the neck versions are a little bit smaller versions of the lumbar versions at least to begin with, but they've become more sophisticated in the neck because of the faster and more widespread adoption that we've seen with neck artificial discs. Like I said, there are two FDA approvals for the lumbar spine, where there are eight FDA approvals for the cervical spine for one and two level. There are some differences there.
Dr. Sanjiv Lakhia: 19:38
Are there disqualifiers? If a patient comes to me and says, "Hey, I want to get an opinion about an artificial disc, but I had surgery on my disc five years ago." Are there things that would disqualify a patient from being a candidate for consideration, let's say in the cervical, spine for this type of surgery?
Dr. Dom Coric: 19:55
Yes. That's a great question. The answer is there are exclusion criteria and in fact, that's why there's still a lot more fusions done then artificial discs, because artificial discs have a much more stringent inclusion criteria, basically it's for younger, healthier looking discs that already don't have a lot of wear and tear changes, or what we call spondylosis.
Dr. Dom Coric: 20:18
The disc has to be the primary culprit, the joints in the back called the facet joints, you can't have a lot of wear and tear in those because, again, the artificial disc or total disc replacement is what it sounds like, you take out the disc, but that's all you take out and you put an artificial disc, so you're still dependent on the facet joints from the back and artificial disc are FDA approved for one or two levels in the neck. So for people with multiple levels, three, four, five levels, that's typically considered an exclusion criteria. People who have deformities of their spine in terms of scoliosis or kyphosis typically aren't addressed with artificial discs. Artificial discs are really for more focal one or two level problems in a younger, healthier population.
Dr. Sanjiv Lakhia: 21:04
That's a very good clarification there. If someone's listening and they're sitting there wondering, hey, could I benefit from this? I think those are some good questions to ask yourself.
Dr. Sanjiv Lakhia: 21:13
As we look at the difference between the cervical and lumbar, I think you've touched on quite a bit of this, do you see the same type of results in terms of positive outcomes for patients that get disc replacements, whether it's in the neck or low back?
Dr. Dom Coric: 21:30
No. I would say that the success in the low back isn't quite as high as it is for the neck. That has to do, again, exactly what we were talking about previously. Typically, people have a pinched nerve and that's what you're operating on in the neck. Typically speaking, if you're able to free up that nerve, about 90% of people will show really very positive results. When you're operating on people who have primarily back pain, axial back pain, in other words, the more I do the more my back hurts, It has been my experience that more respond in the 70% category. Literature would suggest anywhere from 50-70%. I would say that my own personal results are more in the 60-70% for low back and more in the 90% range for the neck. But that has to do, again, with the bottom line of what it is that you're operating on.
Dr. Sanjiv Lakhia: 22:23
In the cervical spine, are you seeing a decrease in the incidence of the adjacent level issue that you might encounter with cervical fusion surgery?
Dr. Dom Coric: 22:35
I got to tell you that, Sanjiv, that's a loaded question, because that is something we could spend a lot of time talking about it in a fairly sophisticated fashion, as far as what the literature would show. The short answer is that the rate of people wearing out an adjacent level after cervical surgery is so low, it's probably only about 1 or maybe 2%, that in order for you to really show those results, you either have to do a study that has literally thousands of patients, or you have to do a study that follows those hundreds of patients for five, 10, 15 years.
Dr. Dom Coric: 23:11
Like we talked about earlier, we're just now starting to get some of that long-term followup. I would tell you that the jury is still out, but I've seen enough positive evidence once with the long-term followup that I would say that it does have an impact. I wouldn't say that there's an evidence basis to say definitively that it 100% decreases the rate of adjacent level disease, I would say that there is enough evidence to point in that direction, but that jury will come back as more evidence comes out, as we get longer term follow up from some of these early studies.
Dr. Sanjiv Lakhia: 23:45
All right. Two more questions I want to hit you with on this topic, and then I'll let you talk about some of the work you're done with the facet joints. I've had these questions from my patients several times, and I didn't really know the answer, so I want to get it from you today. Let's say you're in your forties, you go in, someone sees you, and they get an artificial disc done for a cervical radiculopathy. They're doing great. They want to know, how long is it going to last? For example, in the orthopedic world, you'll hear 10 to 15 years for a total knee or total hip. Is there a shelf life on these products for the cervical spine?
Dr. Dom Coric: 24:17
We have the answer to that, and the answer is that there really is not a shelf life. The idea there is that these things are designed to last the rest of people's lives. Having said that, if you're getting an operation in your twenties or thirties, the rest of your life could be 50, 60, 70 years, and the discs haven't been long enough for us to know that definitively. But the idea is that they won't wear out in a predetermined period of time.
Dr. Dom Coric: 24:44
Having said that, there are multiple factors that can affect the wear of the disc, such as what it is made of, how it was placed, what kind of work or life people are going back to. But the idea, like you said, with hip, or at least early on with hip replacement surgery, was wait as long as you can, because we know you're going to need another one in 10 or 12 years. That's not really the case anymore. There's a longer shelf life. That was certainly what people said as early as five or 10 years ago with artificial hips and knees to some degree.
Dr. Dom Coric: 25:16
We're not saying that we go in with the idea that it would last 30, 40, 50 years, that's based on some of the biomechanical testing that is done, where they cycle these things biomechanically for a million cycles. A million cycles are considered to be more or less equivalent to a year of life, and so they'll cycle them to 20, 30, 40 million cycles and then the idea is, well, maybe this would last 20, 30, 40, 50 years. That's the idea, but like I said, they haven't been around long enough for us to know that for sure.
Dr. Sanjiv Lakhia: 25:45
That's fascinating though, that they put it to the test, so to speak. I think for me, it makes sense from a... I have an engineering background and it just makes sense cervical discs should outlast a total knee from a weightbearing perspective, although there's more degrees of freedom in the neck, certainly. But I think if you take care of yourself, you don't get into major trauma or issues, sounds like you'd you be a good shape after having that done.
Dr. Dom Coric: 26:08
I would agree with that. I think that you're exactly right. You're just not seeing the same stress load that you would see with an artificial hip or an artificial knee.
Dr. Sanjiv Lakhia: 26:19
Do you want to pivot a little bit? You talked before about the importance of the facet joints as being part of the whole vertebral body just complex. Talk to the listeners a little bit about some of the research you're involved with as it pertains to the lumbar facet joints.
Dr. Dom Coric: 26:32
Sure. Like we talked about, there are FDA approvals for lumbar artificial disc and cervical artificial discs, and to even take a step back from that, like you just explained, the spine really is a three joint complex. There is a disc in the front and there's two facet joints in the back, one on each side. That's three joint complex, one disc and two facet joints.
Dr. Dom Coric: 26:56
When you do an artificial disc, you have to make sure that the disc is the pain generator, the disc is the pathological part of the spine, but that the facets are in good shape. When you do a fusion, you don't have to do that because typically when you do a fusion, you stop the motion completely at that level, so whether it's coming from the disc or the facet joints is irrelevant because you're shutting the whole segment down.
Dr. Dom Coric: 27:20
With artificial discs, it's super important that you're able to just focus in on a bad disc itself, as opposed to the disc and the joint, the facet joint in the back. Now, when you do, conversely, people come in, they have good discs, but bad facet joints, and so you say, okay, we've got to take out the facet joint, but do we necessarily have to do a fusion because the disc is not that bad? The idea there is, take out the bad facet joints and then replace it. Instead of doing a fusion, you would replace it with an artificial facet.
Dr. Dom Coric: 27:53
There are no FDA approvals for that. There have been several devices that have been in study over the past two decades, including one that is currently an active study right now, and that's called the TOPS artificial facet. That is an operation where, instead of, like we talked about with lumbar artificial discs you're operating on people who have primarily low back pain, with lumbar facet replacement you're operating on people who have primarily leg pain and some element of back pain, and they have bad joints and those bad joints have resulted in stenosis and spondylolisthesis.
Dr. Dom Coric: 28:30
As you know, stenosis is narrowing where the spinal nerves are and spondylolisthesis is a slippage of one vertebral body on the next. I'm really excited about this technology because it is focusing on the cervical arthroplasty, cervical artificial disc focus on nerve pain, this is more of a procedure that focuses on nerve pain.
Dr. Dom Coric: 28:53
Also, additionally, the lumbar artificial disc have to be taken out from the front. You have to do what's called an anterior approach, which is a less common approach to the spine. Whereas the lumbar artificial facet is taken from the back, which is more of a traditional standard low back midline operation, where you go, we remove the bone, put in rods, and then instead of connecting those rods to... I'm sorry, put in screws, and instead of connecting those screws to rigid rods that don't move, which is a fusion, you connect those screws to a flexible device that maintains the motion and essentially replaces the facet.
Dr. Sanjiv Lakhia: 29:31
That's amazing. I think the take home point here is that there's a lot of cutting-edge research being done and you're on the forefront of it and our group in general. If you're out struggling and you're listening to the podcast today, feel free to reach out to us and see what can be appropriate for you.
Dr. Sanjiv Lakhia: 29:49
Dom, unless you had anything else you want to add on artificial discs I want to close the episode with just a couple of questions about your personal health habits. I always like to pick the brain of the people I interview.
Dr. Sanjiv Lakhia: 29:59
You're a giant in the field of neurosurgery. You work from sun-up to sun-down. You've been doing it for decades now. What have been your go to health habits to keep you functioning at such a high level?
Dr. Dom Coric: 30:13
Well, that's very kind of you to say, Sanjiv. Having said that, like you said, there's nothing magical about it. I think there are things that we all know we should do, which is first and foremost have some kind of work/life balance. Everyone understands that we like to think that what we're doing is important, we're helping people. But having said that, you can't help other people if you yourself are not of sound mind and body. One way to do that is to put perspective that you have a family and you have to have that work/life balance. You have to enjoy doing things with your family. You have to just put work aside and deal with family on a regular basis to have that balance.
Dr. Dom Coric: 30:51
Because you're familiar, and I think most of the people in the medical field are familiar with it, you can't do what you do without a support system. At the office, that support system, you're going to have an administrative assistant, you're going to have a mid level provider, you're going to have a nurse, you're going to have a nurse assistant. People who allow you to do what you can do. The same thing goes in your personal life. You can't do what you do if you don't have a wife or a family that supports you, or significant other. That is super important.
Dr. Dom Coric: 31:20
I'd say first and foremost, you have to be able to strike that balance. I think as a young doctor, that is especially hard because you feel like you have to earn your reputation, but as time goes on, you begin to realize that it's just not sustainable unless you're having relationships with family and friends, the people around you that make my life meaningful to you. I think that's first and foremost.
Dr. Dom Coric: 31:40
The second thing that I think you have to do is some form of regular physical exercise. It doesn't mean that everyone has to run a marathon or a triathlon, but you have to cut out an hour or two of exercise a day for at least three or four days a week. And like you exercise your body, I think you have to exercise your brain.
Dr. Dom Coric: 32:01
One of the things that I stopped doing once I started my residency and I was in early doc, I became functionally illiterate. I just basically stopped reading as something that was an enjoyable thing. I would only read medical literature, things that were relevant to what I was doing. And that, to me, was a big mistake.
Dr. Dom Coric: 32:19
One of our older partners here, Jerry Petty, is the one who got me back into reading as an educational tool and as a mental exercise and to read for pleasure again. Now I'm back to being at least somewhat literate in things that are not directly related to medicine. I think that that's important.
Dr. Dom Coric: 32:37
If I had to rank it, the three things I would say that give me sanity in my life are family and friends, number one, number two, an ability to have physical exercise and to do whatever is sustainable, three to four days a week minimum, and then to have some sort of mental exercise that is away from medicine, that has to do with just reading or being involved with some other activity besides medical activities.
Dr. Sanjiv Lakhia: 33:03
I really love that response. I've had Joe Cheedle on the show and Mark Smith and Tony Asher, and each one of them have answered that question differently. Mark, he also talked about the importance of exercise as his stress outlet, and Joe is really big into exercise. I don't know how the guy finds the time, but he's into marathons and Orangetheory, and he's got a special diet he's on. And then Tony talked a little bit about spirituality.
Dr. Sanjiv Lakhia: 33:32
But bringing up the idea of the family and support network, I think that's fantastic. It's important, I think, for listeners to understand that there's other sides to us as practicing physicians and the fact that we take the time to nurture that side makes us better doctors in the long run.
Dr. Sanjiv Lakhia: 33:48
I know that was some personal questions. I really appreciate you sharing that with our listeners today. I think overall I really enjoyed this interview, Dom. I learned a ton. I feel better equipped myself to answer some of these questions that my patients have. I'm certain that those who download the episode and take a listen to it, might find a new path forward. I want to thank you so much for your time today.
Dr. Dom Coric: 34:10
Thank you, Sanjiv. Thanks for having me. I really enjoyed it. Appreciate it.
Dr. Sanjiv Lakhia: 34:13
Absolutely.
Outro: 34:16
Thank you for listening to this episode of Back Talk Doc, brought to you by Carolina Neurosurgery and Spine Associates, with offices in North and South Carolina. If you'd like to learn more about Dr. Lakhia and treatment options for back issues, go to backtalkdoc.com. We look forward to having you join us for more insights about back pain and spine health on the next episode of Back Talk Doc. Additional information is also available at carolinaneurosurgery.com.
