Podcast Transcript: Exploring Intradiscal PRP for Back Pain Relief

[Dr. Guilherme Santos]:
To your point, I think a lot of the lack of awareness has to do with what treatments are out there and available for patients from a specific disease. You know 20 years ago, we all focused on what we call posterior column syndrome, so facetogenic back pain, right? Why? Mostly because we could to a certain degree address and treat facetogenic back pain, but 20, 25 years ago, there was not a lot we could do for anterior column syndromes, meaning discogenic, vertebrogenic, or disco-vertebrogenic pain.

I believe that now with, I wouldn't want to say that the beginning of, but the rising of orthobiological treatments being applied in pain medicine, specifically in the spine, everyone suddenly becomes more aware of anterior column syndromes because now we have something that we can offer patients that offers a potential line of treatment. Obviously, it won't work for everyone, it's not a miracle drug, but it's derived from your own body, your own peripheral blood. If you do the procedure and it doesn't work, at least under normal circumstances, you won't face any major complications or side effects from the procedure itself except for the small but non-residual risk of infection and post-procedural flare-up of pain for a few days and all of that stuff.

Having said this, most, I'd say, up-to-date literature suggests that about 35 to 40, 45% of cases of axial non-radicular back pain, low back pain, is generated from discogenic sources. It comes from the inflammation and late-stage degeneration of the lumbar intervertebral discs. What I say to my patients when they come in with axial low back pain, no red flags on physical examination, and before we start ordering any sort of MRIs, CTs, whatever it may be, if you present with these symptoms and your physical exam is positive for this and this, you're probably, like most of my other patients, have an about 50% chance that your pain is coming from one of your discs, and your discs may be degenerating.

It's possible that it's one disc, it's possible that it's two to three discs, obviously that depends on the patient you're treating. If you're treating someone who's 30, 40, maybe 50 years old, who's never been obese, has always taken care of him or herself, and always practiced mild to moderate physical activity, is in relatively good shape, then you're probably looking at potentially one or two level disc disease.

If you're treating a patient who's in their 70s or 80s, obviously we all know it's multilevel, multi-segmental disc disease, and those cases are always harder to approach and to take care because anterior column has been suffering for 30 or 40 years, then the posterior column obviously tries to compensate and also starts to show signs of wear and tear, and then where do you begin? Then we can get into the functional spine unit conversation, and should you treat everything? Should you treat potentially the primary generator first? Those are all controversial topics or topics that at least get me interested in chatting about them.

[Dr. Jacob Fleming]:
Excellent overview. As you said, this discogenic back pain tends to be something we see through really up until the end of life basically in terms of increasing prevalence, but it can also be a young person's disease. What I see is that a lot of patients in their 30s or 40s may come in and have classic signs of this axial low back pain that's been going on for some time, typically worsened with flexion, sustained hip flexion tests can tease this out.

To your point about the lack of availability of treatments up until in the recent history, a lot of these people have been put through medial branch blocks and even rhizotomies just looking for some sort of help, and a common refrain is, "Yes, I didn't really get much benefit out of it," but yet, it's something that is commonly done. This class of patient who walks in, mid-30s, 40s, and they have this axial low back pain that's worsened with flexion, typically if they've had an MRI, a lot of times the patient, by the time they've come to me, has already had an MRI done and work up for what's being done. We'll see varying degrees of degeneration of the disc on the MRI.

I'm curious, do you use any sort of scale when evaluating the disc on an imaging nature before going towards an intervention?

[Dr. Guilherme Santos]:
Most, I'd say most of us who do intradiscal procedures, obviously everyone works with MRI these days, right? There's no point in arguing for an intradiscal treatment if you don't have access to an MRI, obviously. I'd say I use Furman grading, which I believe is what most people who do intradiscal procedures work with. I get a T2 weighted MRI, I'm looking at how my disc is looking.

With Pfirrmann grade, I'd be looking at most of my patients would be Pfirrmann 3, Pfirrmann 4, most of them, I'm looking to see if in my MRI, if I'm getting any high-intensity zones, T2 weighted images, looking at the posterior part of the annulus, seeing if it shines bright, brighter than CSF. If I have a patient that, on clinical examination, presents with axial low back pain that doesn't refer below the gluteal folds, pain that is mostly exacerbated on flexion, like you were saying, patients who notice a big difference in their pain between sitting and standing positions, pain gets much better when they're lying down.

Then you do an MRI and you have one, two-level discs who lost about 30, 40% of their normal height, you know they're shining bright on T2 weighted images on the posterior annulus. Then you're probably on those patients also looking for modic type 1 changes. I'd say the big ones you're looking for on imaging are, get your T2 weighted images, look at the posterior part of the annulus, see if you're getting HIZ, high intensity zones, compared to see if they're shining brighter than CSF on those images. Then see if you have modic 1, potentially modic 2 type changes. If you have those, you're probably looking at a patient that has a discogenic low back pain to a degree.

Now, the question is it only discogenic low back pain or the disc is suffering? Obviously, the elements that are protecting the disc from slipping further and further away in the posterior column, the facets, to a degree, will also start to bear some suffering and some wear and tear. In most of these patients, before I do an intradiscal treatment, I end up doing a diagnostic medial branch block to see what percentage of patient's pain is coming from the posterior column versus the anterior column.

It's very hard to distinguish that based solely on clinical examination, the classical maneuvers for a facetogenic pain are not very sensitive or specific. The classical, it gets worse with hyperextension. That's not always true. Some patients with discogenic low back pain can also have increased pain with trunk rotations, which can get mixed up with facetogenic pain as well. Before I do any intradiscal treatment in my patients, I do a medial branch block of the levels that I believe are the levels that are suffering.

I'd say in most of my patients that I feel confident that it's discogenic low back pain, about 70% of these medial branch blocks are negative. After I have a negative medial branch block, I'm confident enough to tell the patient, "I believe if we do an intradiscal PRP treatment, your pain is potentially going to decrease in a clinically significant way." I guess the controversial topic anytime you talk about discs is, "What's your take on discography,?" That's always the elephant in the room is, "What do you do regarding discography? Are you doing a discogram or are you obviating the need for a discogram?"

In my practice, this can be controversial. I do discography typically for discogenic low back pain. That's just because I find that one, there's a very nice 2009 10-year matched cohort study that won the ISSLS prize that year. It's from Dr. Karagi, I believe, and it's a 10-year matched cohort study on the risk of discography causing further disc degeneration and post-discography, a herniation of the intervertebral discs.
What this paper showed was that discography was positively correlated with an increase in disc degeneration in the months to years following the procedure. They also reported non-residual numbers of post-discography herniations. I typically avoid discograms. I might do a discography if I'm very in doubt between two levels, but most of the time, if both levels show degenerative changes on imaging, most of the times, I end up doing both levels at the same time.

[Dr. Jacob Fleming]:
Excellent. That's a very interesting strategy. You're using the medial branch block as an exclusionary diagnostic approach. If the bulk of their pain is coming from the posterior elements, then presumably, you'd proceed ahead with something slightly more definitive such as a rhizotomy or any of the other intrafacetal treatments. Then moving towards the therapeutic treatment of the disc, skipping past the discography.

[Dr. Guilherme Santos]:
If my medial branches are positive, lots of times, what I end up doing is I end up doing a facet treatment with PRP. The data out there on intraarticular facet joint injections for low back pain with PRP is pretty strong. There's multiple level one studies showing security and efficacy at 6 and 12 months post facet joint injections. Those, I'm very okay with doing them and I do those before doing the intradiscal treatment.

The reason is if I can avoid doing an intradiscal procedure and I'm doing just the facet injections which are a more conservative, less risky treatment or less aggressive treatment if you want to put it that way, and that's enough for the patient, I get away with that and the patient gets enough pain release, pain decrease. If that is not enough, then we can talk about doing the intradiscal treatment as a step number two following the facet injections.

Mostly, I try to avoid radiofrequency ablations unless it's a patient that has severe severe facet hypertrophy to a point where I believe I wouldn't be able to get my needles in the facet joints. If I feel confident enough that I'd be able to get my needles within the facets, I try to do the facet injections with PRP before doing a lumbar radiofrequency ablation treatment.

[Dr. Jacob Fleming]:
I like that strategy a lot. Our situation in the US is interesting. As you probably know, a lot of what happens in the US healthcare system stems from policies at Medicare and Medicaid levels. Recently, there's been a lot of changes and a lot of stringency associated with facet interventions, which I got to experience a lot during my fellowship in writing letters of medical necessity and these type of things. It really clamped down and my preference has always been to perform intrafacetal injections rather than rhizotomies for reasons you said.

It is just a less invasive thing. It's frustrating, though, that depending on who's on the other end reviewing the request may say, "Well, why do you want to do a facet injection? Is the patient not eligible to have a rhizotomy?" Which, to me, seems completely backwards. The rhizotomy is a more expensive and slightly more invasive treatment. If the patient can do well with an intrafacet injection, which they often do, six months or more. I've had some patients who got by two years with a single facet injection. It can be very frustrating to have to deal with those sort of things.
I did also want to address PRP in a nutshell. Of course, here, I'm curious about the situation in Europe and Spain specifically. Here in the US, no insurance will cover PRP. These are on a cash-paid basis. That being said, still have gained a considerable popularity. It is frustrating to know that this is a very viable treatment option and some patients won't have access to it. I'm curious, are there similar obstacles in your healthcare system?

[Dr. Guilherme Santos]:
There are. Most insurance companies in Spain, I don't want to say all of them, but most of them do not cover PRP treatments as well. Patients have to pay out of pocket for the PRP treatments. Now, I work in the public system and I work in the private system as well. My practice varies depending on if I'm at the public system or at the private sector. At the university hospital, at the hospital clinic, which is the hospital I work with for the public healthcare system, we actually got PRP to be approved.

What that means is within a certain budget that we get each year to be used in regenerative medicine treatments, a patient doesn't have to pay for the treatment. If I elect to do a radio frequency ablation versus a PRP injection, it's because, for whatever reason, I believe that the PRP would be more adequate or the radiofrequency ablation would be more adequate for this specific patient.

In the private sector, that changes a lot because radiofrequency ablations just like in the States, get covered by all of the, or most of the insurance companies, where is as PRP is not.

In the private sector, I end up doing a lot more radio frequency ablations than PRP injections because of that. To your point, a great number of patients each year are coming to my private appointments and asking me to have PRP instead of having the radio frequency ablations.

They are, most of them, or a greater number each year is okay with being out of pocket for the PRP injections before going the – I like to call it the destructive way. If you think about interventional pain medicine, I always like to tell my patients, "Listen, in pain medicine, there's three types of doctors. There's the destructive doctor, the guy that ablates and burns and freezes everything. There's the trickster, which is the guy that messes up with your brain. Those are the neuromodulators. The implant devices that trick your brain into not feeling the pain. Then there's the docs who try to regenerate the tissue."

If we're able to regenerate it or not, that's a different conversation. We're probably not still at the level where we would like to be. I tell my patients, "In pain, there's three different strategies that you can focus on." Obviously, most doctors end up having a mix of two or three things from each treatment pathway. I try to avoid destructive techniques, ablation techniques as much as possible. If I can get my patients down the regeneration pathway, treatment pathway, I'd much rather be the doc that tries to regenerate instead of the doc that tries to ablate. Although obviously, I do a fair bit number of burnings and ablations myself too.

[Dr. Jacob Fleming]: Sure. I love that trifecta description of pain medicine. That's something that I think patients can really understand. It reminds me of an interventional cardiology talking about the plumbing versus electrophysiology as the electrician. This kind of explanations can really help patients understand the different strategies. As you alluded to the regenerative part of this, so let's talk a little bit more about PRP. For those of our listeners who just don't really know much about it, what is PRP and how is this a potentially regenerative treatment?

(2) Preparation & Formulation of Intradiscal PRP

[Dr. Guilherme Santos]:
Let me try to get a picture here of how everything looks at the end of the preparation. I think this makes it a little bit easier to understand. This is how a typical intradiscal PRP preparation looks like. PRP stands for platelet-rich plasma. What that means is we collect a blood sample from your peripheral blood and then we put it inside a centrifuge and we spin it really quickly for five to 10 minutes, depending on the system you have.

What that does is it separates your peripheral blood into several layers. The bottom layer, the denser, the heavier layer is where you have your RBCs, your red blood cells. We're not interested in those for this specific kind of treatment. Then immediately above the RBCs, you get what we call the buffy coat. The buffy coat is where a lot of the platelets and the leukocytes, the white blood cells are located.

Then immediately above that, that's where you get your plasma with a lot of platelets, a lot of proteins. We're mostly interested in getting this more superficial kind of layer. We're interested in getting the plasma. Then we can talk about either including or excluding the buffy coat, which would mean the difference would be if you would be working with what we call a leukocyte-poor or a leukocyte-rich or enriched concentrate. The difference being if the average cell count of your leukocytes is below baseline or above baseline.

If it's below baseline, you're working with a LP PRP concentrate, meaning leukocyte-poor platelet-rich concentrate. If you're working with a lot of leukocytes, a lot of white blood cells, and the white blood cell count is above baseline, then you're working with what we typically call an LR PRP concentrate, meaning leukocyte rich or leukocyte-enriched concentrate. We can get to that part a little bit further into the discussion. For the sake of simplicity. We get the peripheral blood from you if you're a patient, we get the RBCs, the red blood cells out, and then we get the more superficial layer, the platelets, and the plasma. That's where you can see on the big 20cc syringe that is here in the middle of my screen. When you're working with platelet-rich plasma, most systems either have what we call a single spin or a double spin system.
A double spin system just means that after you centrifuge once and you get rid of the RBCs, you centrifuge everything again to try to concentrate the most amount of platelets possible in the least amount of volume possible. This is important for intradiscal procedures because obviously, the lumbar disc has a very limited volume of medication that it takes, where most discs take up to 1, 1.5 cc's, maybe 2 cc's if you can get away with it. What that means is you have a very low volume of medication that you can actually put inside the disc.

Obviously, we're trying to squeeze as many platelets possible into as low a volume as possible. That's where you can see on the very small 10cc syringe to the right within the orange highlighting, meaning that that's my end solution. That's my last two cc's of PRP that I'm going to be injecting inside the disc. Then the other cc, the other small 1ml syringe has calcium chloride, which is what we call an external activator. It's also controversial if you need to use an external activator or not, I choose to use one before doing my discs.

For simplicity sake, you basically try to get as many platelets as possible in the least amount of volume possible, and then put those platelets inside the disc. Basically what you're looking for is all of the growth factors, we call them proteins that help our tissues repair after any sort of trauma or injury happens. We're trying to get all of those in a very super- physiological concentration within the disc. Then hopefully, those will help trigger your repair mechanisms within the disc and will help fight the degeneration of that disc.

[Dr. Jacob Fleming]:
Fantastic. Thank you for that overview. As you alluded to, the dose is something that's really important. This is something I've seen a number of orthobiologic experts allude to and really harp on. Don Buford is one who comes to mind who is really all about the dosage and a big critic of these papers that come out and say, "Oh, no benefit of PRP." Often in those papers, they report no dose or they report no dose, but calculating it back, it's quite low. This is something that's really really important in terms of the treatment efficacy. As you said, the disc being a very small volume that we need to get the maximum amount into.

[Dr. Guilherme Santos]:
A curious thing that's been shown in the lumbar disc specifically is that the analgesic effect of your intradiscal PRP actually correlates linearly with the PRP dose, meaning with the absolute number of platelets you can actually get inside the disc. That's been shown in two level-one studies. That means that obviously, you want to try to get, we now believe, up to tenfold of your baseline count inside the disc. If we can do that, we're probably looking at a treatment that's going to help the patient a great deal.

The problem is it's not easy. Not a lot of commercial systems out there are able to concentrate to a degree where you can regularly get up to tenfold concentration of platelets into such a low volume. Not a lot of systems are able to do that and to reproduce that consistently. If you're doing 100, 200, 300 treatments a year of your patients, you might get away with 20 or 30 that are above that level. To consistently get in that range is key to making your clinical results obviously what you want them to be, which is mostly positive, obviously.

(3) Anatomic Approach & Fluoroscopic Guidance