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Melanie Cole (Host):  Welcome to UF Health MedEd Cast with UF Health Shands Hospital. I’m Melanie Cole and today, we’re discussing when spinal fusion is necessary in lumbar disease and back pain. We’ll break down the indications for lumbar spinal fusion while covering the different types of procedures available.  Joining me is Dr. Daniel Hoh. He’s a Neurosurgeon at UF Health Comprehensive Spine Center and an Associate professor in the Department of Neurosurgery at the University of Florida College of Medicine. Dr. Hoh, It’s a pleasure to have you join us today and before we discuss fusion procedures, what are some conservative measures that you might try before discussing back surgery with a patient?

Daniel Hoh, MD (Guest):  You bring up a great question which is that there are a lot of different options for the treatment and management of people with back pain. In fact, we know that back pain is one of the top two leading reasons why people will visit their doctor or emergency room in the United States today. and so, as you can probably imagine, overwhelming percentage of people find very good relief with nonsurgical treatment and so, it’s important to just recognize that when we think about the initial management and what for many people is the definitive treatment, does not involve surgery.

Some very simple straightforward things that can be done are use of anti-inflammatory medications, and by that we mean things like ibuprofen. For some people, if it’s an acute type back strain, or a muscle injury, maybe some initial rest followed by gradual return to activity. And for many people, a course of physical therapy can help with strengthening the back muscles, improving range of motion and return to activity. And I would suggest that those are sort of the basic fundamental initial treatments for people with back pain. Beyond that, there are some other more prescribed type interventions that might be helpful such as a short course of oral steroids which can help with acute inflammation and other perhaps less invasive procedures such as spinal injections.

Host:  So, then let’s discuss the different types of spinal fusion procedures Dr. Hoh. Tell us what’s exciting in your field. What’s going on?

Dr. Hoh:  When we talk about spinal fusion, what we’re generally talking about from the standpoint of a surgical procedure is a operation where we are attempting to stabilize the spine. So, what that implies is that either as part of the operation there is some decompression of the nerves or the spinal cord that creates some sort of instability within the spine that then needs to be restructured or reinforced. The other scenario would be that there is an underlying instability in the spine prior to surgery and that might be a reason for surgery to begin with. The last is that there are certain conditions in the spine that can actually result in a malalignment, what we call a deformity, what oftentimes people think of as a scoliosis within the spine that needs a correction to a more anatomic alignment and then a fusion procedure is done to try and preserve or maintain that alignment for durability.

Oftentimes, what many people think about when we talk about spinal fusion is the implants that we use which is oftentimes in the current era metal screws, rods, plates and so forth. But really the fundamental principle aspect of a spinal fusion is that once we’ve restored alignment or created stability within the spine, we wanted there to be long term durable stability and maintenance of that correction. And what we mean by fusion, what we are actually talking about is getting those segments of the spine to actually fuse together meaning the bony elements of that spine to fuse together. And that’s what drives the long term benefit and long term durability.

So, in terms of spinal fusion procedures, there’s many different ways that we can access and surgically approach the spine in order to achieve that. And depending on the type of underlying problem, whether it’s due to degenerative disease or aging within the spine or whether it’s due to a traumatic fracture in the spine, scoliosis or curvatures or malalignment or a tumor or infection; there might be different approaches we might take that could either be what we call a standard posterior approach, which means an incision on the back side of the patient. Or there are some other more advanced approaches that we call anterolateral approaches that either go through the abdomen of through the side or the flank. And the decision about what type of surgical approach is a really nuanced decision oftentimes made by the surgeon depending on the patient’s underlying condition, their anatomy, whether they’ve had prior surgeries before and so forth.

And so, that’s oftentimes a very detailed decision based on their imaging studies and the underlying problem.

Host:  Thank you for that answer and as we’re on that same topic, discuss a little bit about the clinical indications for lumbar spinal fusion and patient selection criteria because this is not for everybody is it?

Dr. Hoh:  So, I would typically say for the most common reason why we see patients in our spine – Comprehensive Spine Center for people with common sort of routine degenerative disease of the spine that might be for a surgical indication; generally one of the deciding factors we’re determining is again, is there underlying instability within the spine that might be age related or chronic in nature or due to a prior operation. What we oftentimes see is what’s called a lumbar spondylolisthesis and that’s a very common degenerative condition which results in a malalignment and oftentimes instability within the spine. That would be probably one of the most common reasons we would consider performing a fusion operation on someone who has an indication for surgery.

The other more common reason is that there’s a malalignment in the spine and we oftentimes see that as well in people as they age, there’s a progressive loss of disc height or degeneration of the spine where you see an abnormal curvature in the spine. That can be either on the coronal plane meaning that they have a tilt from one side to the other, either the left or the right. Or what we call the sagittal plane which very typically we see as people who are hunched forward. If there’s an underlying structural problem with the spine that is resulting in that kind of malalignment, then that would be a role for fusion but really the idea there is we’re trying to correct the underlying deformity and then fuse the spine, so it maintains that alignment for duration.

Host:   Dr. Hoh, so do you feel that the current definitions of spinal instability uniformly accepted and applied across the board, do you feel that class one and two scientific evidence regarding this is relatively scarce? What are you seeing among your colleagues as far as some of the challenges and decisions when you’re thinking about doing spinal fusion?

Dr. Hoh:  The diagnosis of instability generally falls into one or two types of modalities. The first is the clinical presentation and the second which we very much rely on is the radiographic definition of instability. So, what I would say is that instability from a radiographic standpoint is generally well accepted and standardized and so the typical way we would assess that is with what we call either dynamic imaging or weight bearing imaging. So, a good example would be a routine patient that I might see in the office may have a MRI of the lumbar spine. Typically MRIs are performed in the supine position so the patient lying on their back. What I would very routinely get is also an x-ray with that patient standing up. And even though the MRIs and x-rays are different imaging modalities, I can get a very good sense of the overall stability of the spine when the patient goes from a supine position on the MRI to weight bearing or standing with the x-ray. If we see shifting of the vertebrae our of alignment during that transition from supine to standing; that’s a very classic example of what we define as instability within the spine.

Another way of also assessing that is with what’s called flexion extension x-rays. What that allows us to do is we have a patient standing up in the x-ray machine and they simply flex forward and extend backwards and what we’re looking at during those normal physiologic ranges of motion, do we see the spine move in and out of alignment. Again, if we see that, that’s also very standardized classic definition of instability.

Host:  So, then let’s talk about the results of a recent randomized controlled trial of decompression versus without fusion for spondylolisthesis which you mentioned briefly before.

Dr. Hoh:  Yeah, so there was a very highly publicized issue of the New England Journal of Medicine that came out a few years ago in which they published side by side two separate randomized controlled trials. In brief, one of them was performed in the United States. It was a multicenter study. And the other was performed in Europe. They studied slightly different patient populations but had a very similar hypothesis. The real question of both studies were in patients with lumbar stenosis with spondylolisthesis, is there a benefit of adding fusion to decompression versus decompression alone? And that was at the nutshell of both of those studies. The patients were randomized either to a decompression only or decompression and fusion and again, the purpose was to determine if adding fusion to a decompression had benefit.

The reason why this issue of the New England Journal of Medicine got a lot of publicity was because the results seemed to suggest that there was no added benefit to performing a fusion in addition to a decompression for patients with lumbar spondylolisthesis. And this really came to contradict what had been long held and believed and actually proposed by numerous national societies, spine surgical societies about the indication for fusion in the setting of spondylolisthesis. But on careful review of both of these studies it became clear that the conclusion that adding fusion was not a benefit was really suspect based on those studies.

And so, to summarize, the European study suggested that there was not added benefit for fusion in that setting but really in that study, they only studied patients out to about two years. And for many spine studies, certainly two years is a reasonable length of follow up after to assess outcomes. But what we know is that the added benefit of fusion if it is to prevent – is to treat instability and prevent delayed instability related problems; then two years is probably not an adequate time point to really assess for that added benefit of adding a fusion. So, the study that was performed in the United States, which was the lead author was [00:10:32], what they did was they followed patients for two years and then subsequently followed them beyond two years up to four years and sure enough, just as one would suspect, they found that up to two years, there was similar benefit between patients of having decompression alone versus decompression and fusion but what they found was as they followed those patients beyond two years, the patients that had decompression and fusion has sustained benefit. That’s what we would have expected from the added benefit of the fusion. But those patients that had the decompression alone; that when those patients were followed beyond two years; over one third of those patients developed recurrent problems that were related to instability and then subsequent had a repeat operation and that’s where we see the added benefit of fusion to decompression in patients with spondylolisthesis.

Host:  So you have any technical approaches that you’d like to share and when you’re speaking about that, is there an issue that you’ve seen in your outcomes with spinal fusion? Do you have an issue with adjacent segment disease?

Dr. Hoh:  As I mentioned before, there are a lot of different ways to perform a spinal fusion. What I would typically say is that for most of the patients we see with very common type of degenerative disease, if there is a good indication for a fusion operation, for example one level or two level fusion operation; there are very good standardized techniques to successfully achieve a fusion that provide long term stabilization of the spine and good decompression of the spinal nerves. Again, there are different ways to do that. A very conventional approach is through what we call a posterior approach, this would be an incision on the backside that allows us to decompress the nerves, place metal implants for stabilization and achieve a solid fusion or arthrodesis across those bony segments.

There are some other more recent advanced approaches that go through the lateral aspect or through the flank that can be done through a very small incision and in certain instances done through the abdominal approach. All of them have nuances that provide certain advantages or disadvantages depending on the patient’s anatomy or a unique consideration such as prior surgery or other comorbidities. And so, each of those become a factor into the decision making about which kind of procedure. What I would say, me and my colleagues at the University of Florida, we employ all these techniques and really take a very tailored patient specific approach in determining what is the best ideal surgical procedure for a different patient.

Host:  Before we wrap up, and this is really such a great topic. As an exercise physiologist and knowing about this procedure, I do find it so fascinating. What’s coming in the future of spine surgery? What’s exciting in your field right now?

Dr. Hoh:  What I would say is and I think this piggybacks on the question you had just asked previously, is perhaps the most exciting aspect about the current future of spine surgery is patient selection. In terms of we’ve gotten to a point where we’ve become quite advanced in our diagnostic modalities, quite advanced in terms of our surgical techniques and really, I think that the next step in advancement is patient selection, determining which patients are the most ideal for surgery and for certain types of surgical procedures. And being able to apply algorithms coming from large data, patient registries and so forth, to allow us to better predict outcomes depending on the intervention in that very specific patient. I will say another important aspect about spine care that we’re involved with now is how do we enhance the perioperative period for that patient to have an optimized experience meaning, prior to surgery, what kind of things from a prehabilitation standpoint can be done to take the most vulnerable patients, what we call frail patients and get them as optimized prior to surgery so that we can expect an outcome that would be similar to perhaps a more robust patient as well as the interventions we do during the immediate postoperative period and transitioning those patients home. Again, to enhance their experience, optimize outcomes and minimize the probability of adverse events.

Host:  Thank you so much Dr. Hoh for coming on and sharing your expertise with us today. That’s such an interesting topic. Thank you again. And that concludes today’s episode of UF Health MedEd Cast with UF Health Shands Hospital. To learn more about this and other healthcare topics at UF Health Shands Hospital, please visit www.ufhealth.org/medmatters to get connected with one of our providers. Please also remember to subscribe, rate and review this podcast and all the other UF Health Shands Hospital podcasts. I’m Melanie Cole.