504- Systematic Review Shows How Adjustments Affect Spinal Biomechanics

Welcome to the Evidence Based Chiropractor where each week we deliver the latest chiropractic research and marketing strategies all in the time it takes to get to your office. Now here's your host, Dr. Jeff Langmaid.

Hello and welcome to the Evidence Based Chiropractor. I AM your host, Dr. Jeff Langmaid. On today's episode, we are back with more brand new research and it is another good one. This is a systematic review on the biomechanical effects of high velocity low amplitude spinal manipulation. We'll dive in, we'll highlight what the research shows us and also translate it into patient friendly communication. Now before we get started, I want to say a few words about our partner over at Leander Tables. They have an awesome deal for listeners of this podcast that means you where you can save up to $1,000 on a Series 950. Check them out. I'll drop a link down in the show notes. If you are on the hunt for a table, Leander Table should be at the top of your list and you can get up to $1,000 off of a Series 950, the best flexion distraction with elevation tables out there. Now, as I said at the top of this episode, today is all about research. We're going to dive into a brand new systematic review that really looks under the hood of spinal adjustments and specifically the biomechanical effects of what we do. High velocity, low amplitude thrust. This study was published in Plus PLOS One in July 2025, so it is hot off the press. Again, the title systematic review of Biomechanical effects of High velocity Low amplitude Spinal manipulation. We we will drop a link down in the show notes. So if you've ever asked yourself or been on the hunt for the answer to the question, what changes am I making when I adjust somebody's spine? This episode is for you. As you're probably well aware, if you've been listening for a little while, then the mechanisms of action for what we do with spinal adjustments are deep and wide. There's a lot of breadth and depth to what happens. We're still learning. It's difficult to pinpoint one thing. But from a biomechanical perspective, this study was taking a look at that and again, it's a systematic review. So they had 33 randomized controlled trials, which is not easy, and they looked at the measurable biomechanical effects of spinal adjustments across the spine. So specifically we're talking about range of motion, facet joint gapping and spinal stiffness. Now the interesting part about this study is that they analyzed studies that had both symptomatic and asymptomatic people. And here's the kicker. They were also looking to see if those biomechanical changes were ever linked to clinical outcomes like pain and disability. And really, nobody's really connecting those dots yet. But that is where I think a lot of chiropractic research is going to go in the future and where this study starts to lay the foundation and the roadmap. So why does this matter? Pretty obvious. You and I, all of us, we know the spinal adjustments that we deliver work. It's the hallmark of what we do. Can we do other things? Absolutely. Do many chiropractors do other things? Absolutely. Whether that's low tech or high tech rehab, whether that's shockwave in your practice, whether that's functional medicine, nutrition, whatever, sport specific training, There's a variety of things that we can all do. But I think most chiropractors would agree, the most high impact item that we can provide is a spinal adjustment. It takes the least amount of time compared to most other things. It provides the highest amount of upside and benefit. And our knowledge around how it impacts people's bodies continues to expand, which is really, really exciting. So again, we know spinal adjustments work. It's been highlighted in the guidelines for neck pain, low back pain, even radiculopathy. But why it works, that's the key question that is still being figured out by researchers. And this paper takes a massive step forward in our understanding of, of what physically changes after an adjustment and how consistent that change really is across different papers. Because if you've been following this podcast or you've been following the research, you know, it's. Research can be kind of confusing at times. I mean, you see, one paper says this thing, the other paper says the exact opposite. A third paper comes out and says, well, we don't know. Research is dynamic. And I think that's something that's really important. And it's something that I've learned throughout 500 plus episodes of this podcast, reviewing probably three to four pieces of research research each and every week. I've literally reviewed thousands of research articles. I don't know if anybody's ever researched more hard fact to figure out, but I'm hard pressed to believe it. I probably read more chiropractic related research than anybody out there. And when I first started it was a little frustrating because for every study that would come out, it seemed like there wasn't an answer. And that's really. I'm going to Say, the punchline is that most research articles don't provide aggressively direct answers. What they provide is frameworks and the ab to ask more questions. And once you understand that, then you can take the research with your clinical expertise, with your preferences, with patient preference, and really put these things into action. So, getting back to this study, let's start at the cervical spine and with cervical range of motion. Of the 33 studies included, 16 specifically focused on cervical spine adjustments and their effect on the cervical range of motion. They found nine of the 16 studies showed a statistically significant increase in cervical range of motion after the adjustment. That's an O. That's a majority of the research. And those words are important, meaning statistically significant. Again, we're always looking for those qualifiers because in research that means something. Now, four of those studies were considered low risk of bias as well. So that again, just like kind of steps up the quality of that research. Flexion, extension, rotation, they were the most commonly improved movements. No surprise to you if you've probably delivered an adjustment today or maybe are on your way to the practice to do so. And timing ranged from immediately post adjustment up to four weeks after the care was delivered. So that's an interesting point as well, because it's not only that the care that you deliver, okay, we see an improvement in range of motion right now while the person's on the table. Wonderful. But it also is important to realize that can last, so to speak, or continue to improve for weeks after just that single adjustment. So you start to stack these things together. Now you can see the compounding benefit of ongoing care. So one study showed cervical flexion improved by over 5 degrees after an adjustment compared to less than 2 degrees in the sham group. So yes, there were super real, super measurable changes. And how much people can move their neck after adjustment, probably nothing world beating there for you to hear. But this just continues to add to the body of literature and being in a systematic review really starts to codify what we know to be fact, basically. Now let's move on to something where it starts. Things start to get a little more interesting and that's thoracic adjustments affecting cervical range of motion. And again, this is where things start to get really interesting. This review Foundation 8 studies that applied thoracic adjustments and then measured cervical range of motion. And all this is wild. All eight? Yes, you heard me right. All eight showed positive effects on neck mobility. So yes, adjusting the thoracic spine can improve cervical range of motion. And every chiropractor who's adjusted mid thoracics to help with neck stiffness. Tightness already knows this, but you've got the data to back it up. So if you have a patient who's maybe hesitant about neck adjustments, it's their first visit in maybe you don't have another tool in your tool belt, so to speak. Except for a high velocity neck adjustment, you're like, ugh, I don't want to make the patient uncomfortable. You can ease into things. And when I say ease into things, there are other avenues you can take, such as adjusting the thoracic spine. Also, as you've probably heard me say multiple times on this podcast, always check the next region or joint, right? Somebody has an elbow issue, you, you want to make sure you're evaluating the wrist and the shoulder. Somebody has a shoulder issue, you want to make sure you're evaluating the cervical spine and the elbow. You always want to check those adjacent regions or joints. The same thing holds true in the spine. So if somebody has a cervical spine complaint, don't get too myopic and say, well, based upon, you know, opp. Qrst here I am only going to look at the cervical spine because I am directly focused on the problem area that is massively shortsighted. Our bodies are super dynamic and our spine is even more dynamic. So understanding that looking at the next spinal region or body joint is a critical component and you should always be doing, I highly recommend all the time, you should be doing that in your practice for multiple reasons. One, it's gonna help your patients get better results. Number two is there's probably some compounding benefit you can provide. So in this case with the thoracic spine adjustment and these studies, to be clear, were adjusting the thoracic spine, only checking cervical spine range of motion, every single time, it improved. Now what happens if you would adjust the cervical spine and the thoracic spine? Well, you're probably gonna get compounding improvement, right? So being able to utilize everything that you can to improve your patients is a really good idea. And it's important again, I'm gonna say, especially for some of the younger docs, maybe sports focused docs, quote unquote, evidence based docs, don't become too myopic. Be sure to be checking those neck spine regions, those next joints and treating them as appropriate, taking care of them, delivering care as needed, even in, even when they're not in pain. Right? These people had cervical spine issues, not thoracic pain. But adjusting the thoracic spine made an improvement. And that's a, we're going to get into the communication of that in a few minutes. But really important to keep in mind. And let's talk about thoracic and lumbar relative to range of motion. The data is a little less clear. There was only two studies that looked at thoracic adjustments and thoracic range of motion. One showed a increase in flexion after a T9 adjustment, the other, no real meaningful change lumbar adjustments. The review couldn't draw any super clear conclusions. That doesn't mean that you're not seeing benefit. It doesn't mean that there is benefit. It just means in the studies that they looked at, it was not hyper clear. Let's tackle facet joint gapping briefly. Three studies in this review used imaging actually to assess facet joint gapping. And all of them, yes, all of them, found increased spacing after an adjustment compared to side posture positioning alone. So yes, you are creating real mechanical change in that joint spacing. It's not just the sound, it's actually a structural movement. Spinal stiffness. Only one study, so limited sample size, no significant change. I've seen this be contradicted in other studies in terms of spinal stiffness, so I'm gonna say that's still an it depends type phenomenon. I think a lot of that depends upon the sample size, the study and how it's conducted and how it's measured. Now, do these changes lead to less pain? One trial tried to link only. This is a challenge. Only one trial even tried to link biomechanical change with a clinical outcome. That means it's not A plus B equals C yet. But that's a massive opportunity for future research and something that could make what you and I do each day in our practices even more persuasive in the eyes of patients, payers, other providers as those items get linked. So how do you bring this into practice? There's a lot of ways you can highlight what we just discussed, but it's important to keep your language simple as well and let people know when you adjust their spine, you're delivering a quick drop, gentle force that increases how your joints move. And there's research out there that shows improvements in range of motion, even in areas that we're not directly adjusting. That's why you might feel a little less stiff, a little more relaxed, a little more mobile, even if we didn't adjust the area exactly where you hurt. So being able to describe that to patients in crisp, clear language only helps you, only helps them, only reinforces the value of the adjustment, the and helps start to educate them on what's actually happening, but using plain language. So some actionable takeaways here. You know, cervical and thoracic adjustments can significantly improve neck mobility, something we see every day, but nice to see in a systematic review. Thoracic adjustments may improve cervical range of motion even without adjusting the neck facet joints do open up after an adjustment. It's not just audible. And in terms of stiffness, there is a more research to be done. So I like this study because it doesn't just confirm what we see and feel each day, it starts to actually quantify it. So if you're looking to bridge the gap between your experience and the evidence, this is a great study to start to lean into. And I think it's a great opportunity to further our understanding, to sort of solidify what we know by looking again at multiple other randomized controlled studies, bringing it together in a systematic review and putting it into language. Hopefully that makes total sense to you and I, but also can start to make sense to the many people, like 85% of human beings on planet Earth plus that have no idea what chiropractic is, how it can help them, or the benefits that they can get from it. So this study doesn't do at all. But it's another brick on that bracket building. It's another brick paver in the road to our understanding. And to me, that's some of the most important thing we can have. Now, before we wrap up, I want to say a few words about turncloud. Minimalist design without being sparse. They've stripped away everything that's not essential. 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