344- Vertebral Artery Changes with Spinal Manipulation
11 Nov 2025 · 0 min
Dr. Jeff Langmaid reviews a study of 168 cervical spine manipulations on cadavers that measured head movement and vertebral artery changes. The researchers found minimal artery length changes across all techniques and levels, suggesting the procedure is safer than feared, though the host still recommends clinical caution.
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. This week we are back with more research research and a brand new study that came out in chiropractic and manual therapies just this year, 2022 and it is all about kinematics of the head and associated vertebral artery length changes during high velocity low amplitude cervical spine manipulation. That's a, that is a mouthful, but it is a great study showcasing what happens to the length of the vertebral arteries when somebody receives a chiropractic adjustment. We'll get into the research will also get into some take home messaging that the research showcases in today's episode. But before we get started, I want to say a few words about the Payday Practice. The Payday Practice is a new book that I released with Dr. Jason Deutsch. It's all about how you can create monthly recurring revenue in your practice to meet your monthly expenses. If you could do that, that is what we call a payday practice. You create more revenue, you have a lot more fun and things are a lot less stressful. We are giving away and gifting a free copy of the new book digitally for a limited time. You can check it out@thepaydaypractice.com again that is the paydaypractice.com. you can pick up a free digital copy for a limited time. We are gifting it to everybody in our evidence based chiropractor and smart chiropractor ecosystems. So if you're interested in a new way to practice, exploring a new opportunity or just checking it out, I'd highly recommend doing so@thepaydaypractice.com but today's episode, as I said at the top, we are talking about an important topic and a pretty serious topic. I know in the last couple of weeks I've seen a post going around social media like crazy and it alludes to some a young woman being injured as a result of a chiropractic adjustment, spinal manipulation and it's been going around like crazy. I don't know too many of the details, impossible for me to comment on that case. But I think this research is really timely in light of that anytime that somebody is injured, whether it is causal, correlative or happenstance, it's Important for us to take a step back, look at what's going on and utilize to the best of our ability the research available to communicate with our patients and make great clinical decisions. To me, that's what this study does. Again, this was released in chiropractic and manual therapies and the title I'll drop the link down in the show notes as well, but it's kinematics of the head and associated vertebral artery length changes during high velocity low amplitude cervical spine manipulation. Why is this a big deal? Well, neck pain is one of the most common reasons people visit a chiropractic practice. It's also one of the most common causes of musculoskeletal pain in the adult population. I think it's either number two, low back is the number one reason why people begin to see a chiropractor. I believe neck pain and headaches kind of vie for 2 and 3. I'm not sure which one takes the cake there, but something we see all day, every day in practice. Whether it's non specific mechanical pain, neck pain, whether it's neck pain with your radiculopathy, whether it is muscle spasm, limited range of motion, torticollis, if you're looking at a younger population typically, or chronic neck pain in an older population due to degenerative changes, osteophytes, stenosis, you name it. There's a host of things that can happen in the cervical spine over time and neck pain as a result of that is one of the most common things we see in our practice as chiropractors. And there's an annual growth, global prevalence is a wide range between 17 and 75%. So that is a big number at the top end and still a pretty significant number at the low end as well. 20 to 75% of people experience neck pain in any given year. So it's a big deal and it costs a lot of money. People are spending a lot of money to take care of it. So where do we fit in? Well, cervical spine manipulation is frequently used as a treatment modality for people with neck pain. And the interesting part is over the last five to 10 years, it's now recommended in many clinical practice guidelines. That was not the case 20 to 25 years ago. And yes, there still are those dinosaurs out there that believe nobody should be adjusted or manipulated in their cervical spine. That's a vestige of the past clinical practice guidelines fully support and actually encourage. The bottom line is when you take care of neck pain, quote, unquote, take Care with medication, it doesn't work. Your body sensitizes. We have numero research studies with disc issues, without disc issues, whether it's mechanical, compressive, chemical irritation that medications rarely take, they don't take care of the issue. They can numb the pain while the body heals. However, often there's a biomechanical challenge, there's a daily habit challenge, there's an ergonomic challenge that's leading to this movement based care such as adjustments or spinal manipulation, one of the top ways to take care of this. And it's recommended. So it's been suggested that head and neck extension and rotation during manipulation may stretch and damage the vertebral artery wall, leading to arterial dissection and potentially even stroke. Now, such damage predominantly occurs at the V3 segment of the artery, which may be vulnerable with elongation. So that's sort of what's been put out there. Now the research that I've seen previously showcases that even when you get into the paraphysiological space, by definition you're not to the point of damage. So you might be beyond normal active or passive. You might be beyond normal active range of motion, but the paraphysiological space is not to the point of damage. Therefore, by definition you're not damaging the vertebral artery. So we're going to take a look at what this research says regarding that. Now, despite the use of a variety of techniques, the current literature reports that head angular displacements during spinal manipulation are small, especially for rotational movements, and that they probably don't exceed normal physiological range of motion. Kind of what we just said there. But there's two sides to the equation. As you can see, there is some data out there. I shouldn't say that actually there's no data. There is a belief that adjusting the cervical spine or manipulating the cervical spine the may lead to a challenge. And we saw that on this social media post. But there's also the questions always is, was that person walking in with something going on in progress? Was that person walking in and they had some predisposed likelihood whether they were gonna go to the hairdresser next or look up in the sky and they just happened to walk into a chiropractic practice. So this is the correlation causation or what I call happenstance. And that's really difficult to parse out. And that's why research like this is important. But it's nice to know that when they looked back at previous research and current literature as well, it doesn't look like when we provide a manipulation and adjustment that the vertebral arteries extend beyond the normal physiological range of motion, which is an important starting point for this. Now, since the thrust phase of an adjustment involves a rapid increase in force and possibly amplitudes, it's important to quantify the angular displacements of the head and neck and the vertebral artery length during this phase of the procedure. That's really what they're trying to get down to. Okay. There's no question that there's a force happening whether it's by hand or whether it's by instrument. And there's no question in many cases specifically by hand, that especially if you're going into a prone or supine adjustment, seated might be a little bit different, but that you're getting in there with some amount of rotation. So quantifying and qualifying that really, really important. Now, purpose of this study was to systematically quantify the angular displacements of the head relative to the sternum and the associated vertebral artery length changes during that thrust phase. And they looked at two types of adjustments, rotation and lateral flexion, and applied bilaterally to each level of the cervical spine, C1, all the way down to C7. So they were really taking all a holistic view at what was going on. They had 168 adjustments performed or delivered. And there were three male cadaveric donors. So these were, this is a cadaver study. So the limitation there is there's not blood pressure, right? So that could be a factor. They point that out in this study, blood pressure can be a factor because of course it's applying by definition pressure to the vertebral artery as the blood flows through. So this doesn't have any of that because it's cadaveric study. However, it makes it a lot easier to really identify what's going on and get precise measurements. So a little bit of a trade off there. So they found that there was no significant differences in vertebral artery length changes, whole artery or the V3 segment during Spinal manipulation applied to the different vertebral levels. So that is really their take home message here. We'll dive a little bit deeper, but that's an important finding. So irrespective of the type of adjustment or manipulation, the side or the level of the application, angular displacements of the head and associated vertebral artery length changes during the thrust phase of the adjustment were small. So that is a very, very important component. Especially when we look at different techniques in different chiropractors performing the Spinal manipulation or adjustment. We've probably all been adjusted multiple times, and we probably all have seen multiple chiropractors adjust. And there's a pretty wide variety in terms of how much rotation occurs, how much lateral flexion occurs. Course, you have to get that joint to tension, put that thrust in to get that release in the gapping of the facets, and really create that manipulation. However, there's a lot of variation in how many of us go about that. So I like this study because they went to different levels, they went to different sides, and they used different chiropractors. So there's a lot of variables there. And pretty much regardless of how they. They quantified things, the length changes were really, really small. And there was nothing that they saw that was really beyond normal limits or into abject injury territory by any stretch of the definition. So there did not appear to be a relationship between the vertebra to which the thrust was applied and the change in the angular displacement of the head relative to the sternum. So that's an interesting fact as well. When people were going through and doing these adjustments, regardless of what level they applied, you know, the head stayed pretty centered. And if you keep your elbow in, you know, I think we all learned you really don't want to, you know, really jerk somebody's head with maximum rotation. Typically, how we learn to adjust is to minimize rotation, and there's still a lot of variability with that. But bottom line is the sternum and the head stayed pretty in line and aligned as these adjustments were performed. So their conclusion was head angular displacements and vertebral artery length changes were small during CMS thrust, chiropractic, spinal manipulation thrust. So there was some variability, but pretty much no matter what the variability was, the changes remained small. So great news for us as chiropractors, with the hallmark of our care being adjustments in manipulation, that it does not appear that there is extreme changes in vertebral artery length. Any changes are small, regardless of technique, side, and level that we're adjusting now. I think it also is something that all of us need to always be cautious of, right? A Hippocratic oath, rule number one, do no harm. So being cognizant of what's going on with a patient, understanding their preferences, their comfort level, and certainly if they have any yellow or red flags, is something we should all be cautious of, cognizant of as we're going through our daily care. But we also should be very confident on the other side of the equation that what we're doing with adjustments, what we're doing when we're adjusting the cervical spine really stays within normal limits. So there is no, I'm going to say there's no reason anything askew should occur during an adjustment really, unless that individual was walking in with something going on already. And that's an important component. Now with millions of adjustments given per year, the variability on providers. There are extreme examples of all types of providers that provide adjustments or manipulation, doing extreme rotation. There are of course, extremes. There's always a bell shaped curve. However, by and large, what we do is exceptionally safe as well. We see, I saw that post going like crazy on social media and I look back and I say, man, we're still seeing 130 to 150 deaths every day as a result of opioid medications. We are still seeing dozens of deaths due to surgical intervention elective each and every day. And it's so rare that we see anything relative to, you know, a manipulation causing an issue. Very often we don't have any of the actual facts. It's sensational journalism. So everything has to also be taken on a scale. That's not an excuse. And that's where research like this is super important to really understand what's going on, but understanding the awareness of it, being able to know that what you're doing is within normal ranges of motion, even when you're delivering that thrust and helping people understand that as well, that this isn't like a rip roaring thing where you're going into injury territory. You're really releasing within the paraphysiological space to help people maintain proper movement, to better biomechanics, to gap the facet joints and to ultimately influence the central and peripheral nervous system. When you can do that, that's how you can gate pain. That's how people improve their range of motion, that's how they improve their biomechanics. And over time, that gives them the opportunity and availability to do what they need from a lifestyle perspective because they're not walking around in pain. And we've seen again between the spinal disc herniations causing pain, injections versus manipulation. Manipulation is pretty much one out every single time. And it's very rare at this point, except in acute extreme cases that injection should be utilized in the cervical spine. Not only is there joint deterioration that occurs due to the injection itself, but quite frankly they're deemed ineffective as far as the research goes. So the bottom line is getting out there, telling the story in a proper way in your community. You don't want to be flippant with it. And you certainly don't be dismissive of what what what you see online. But understanding that what you do is a fantastic way to take care of people, help people find relief from neck pain is a great thing. It is much needed. And with the amount of people struggling with neck pain still getting elective surgery, still going through and taking daily medication, still getting injections, there is still a lot of work to be done, even though the clinical guidelines support what we do. So get out there and have great conversations and know that what you are doing is one of the best ways to take care of people with neck pain. Now, before we wrap up, I want to say a few words about Power Step. Power Step orthotics are what I like. They're what my father uses. They are the real deal. Developed by a podiatrist over 30 years ago, it is a perfect balance of comfort and support and they're offering all listeners of this podcast a free sample pair. You can go over to pro powerstep.com sample again that is pro powerstep.com sample if you need to put in a code, put in E B C. That should work and you can pick yourself up a free pair complimentary pair gifted pair A Power Step orthotics Also, if you are looking to build and grow your practice this year by adding on a new associate chiropractor or a chiropractic assistant, do not go it alone. Rely on gut. You're trying to go through sourcing, vetting, interviewing and hiring yourself. It's not what you do all day, every day. Chiro Matchmakers has a team of 15 recruiters that do this all day, every day. And also on top of that, it's not just about finding anybody, it's about finding the right match. So going through and understanding your practice culture, your job description, your job roles, helps us source and vet at an extremely high level. We're talking cognitive assessments, we're talking every assessment. You need to understand whether this person is going to not just be a warm body in your practice, but a perfect fit to help you be poised for growth. Because we all know hiring the right person can add seven figures to your practice over the course of time. Hiring the wrong person could be a six figure mistake, so you can check that out@chiromatchmakers.com I hope you have a fantastic week in practice and I will talk to you soon. Soon.
Thank you for joining us on this episode of the Evidence Based Chiropractor. If you want to grow your practice, come back for next week's episode. If you want to grow faster, visit theevidencebasedchiropractor.com and join our MD Marketing membership today.
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