Spinal Manipulation in Physical Therapy, Death Throes in Research

Basis for spinal manipulative therapy: a physical therapist perspective. Bialosky JE, Simon CB, Bishop MD, George SZ. J Electromyogr Kinesiol. 2012 Oct;22(5):643-7. [Free Full Text]

My comments:

This paper has an extremely well referenced number of facts seemingly leading to one conclusion, that oddly appears to escape the authors. I think this paper was intended to be a pro-spinal manipulation review paper for physical therapists. However, unless there is some underlying satire I missed, I think they did a great job of debunking spinal manipulation. So if anyone is skeptical of my interpretations please be sure to read the article in whole for yourself and let me know if I missed anything.

Quoted from Section 3.2 on Segmental clinical decision making:

“This model is dependent upon accuracy in determining a dysfunctional vertebral motion segment; however, the literature suggests poor reliability of the assessment techniques. For example, poor to fair inter-rater reliability for spinal mobility testing has been observed (van et al., 2005; Seffinger et al., 2004) and these findings are not improved with training, experience or discipline (Seffinger et al., 2004; Billis et al., 2003). Additionally, the traditional clinical decision making approach necessitates the correction of a specific dysfunction with a specific technique; however, SMT is not specific to a given segment (Kulig et al., 2004; Lee and Evans, 1997). Specifically, the force of SMT is spread over multiple segments (Herzog et al., 2001) and the cavitation (or pop) frequently accompanying these interventions often occurs at segments other than the intended site (Ross et al., 2004). Furthermore, the chosen technique does not correspond to clinical outcomes. For example, clinical outcomes are similar for SMT of varying mechanical parameters (Cleland et al., 2009) and whether the specific SMT is determined by examination findings or randomly chosen (Chiradejnant et al., 2003).”

The above all sounds right on, and in my opinion it says everything. Spinal motion can not be reliably felt or tested for by palpation, more training doesn’t help, and even if it did it still doesn’t matter because spinal manipulation can not target a specific joint anyway. In fact, cracking the back using a technique opposite of what proponents think they need to correct perceived  joint dysfunction “works” just as well. Full stop right there! In a paragraph they concisely and accurately took apart the whole charade. All they need now is a logical conclusion, but rather than coming to one they say:

“Collectively, these studies suggest a general biomechanical effect of SMT as opposed to an effect specific to a targeted segment.”

Biomechanical? Couldn’t it be psychological? I imagine there might be some afferent mild pain reduction due to weak exploitation of gate control theory, but a TENS machine lasts longer and a massage feels better.

Later in section 3.3 they talk about how spine manipulation researchers started to give up on treating specific joints and figured they would just try to figure out what type of person it does works for. Citing Timothy Flynn’s paper looking at clinical prediction rules for who responds to manipulation that blinded neither patient, nor therapist, nor evaluator and didn’t include a placebo or control group. And what did he find. Patients were more likely to respond favorably to spinal manipulation if they had the following 5 characteristics, the more they had being better.

  1. pain duration of less than 16 days
  2. fear avoidance beliefs work subscale score of less than 19
  3. hip internal rotation on one side of at least 35 degrees
  4. lumbar spine hypomobility
  5. pain not extending below the knee

The only variable that seems relevant, is (#4) lumbar hypomobility determined by a spring test, but didn’t the authors already cite research suggesting segmental testing results are unreliable? Otherwise, when I read the above prediction rules, it just sounds like people who get better with spinal manipulation are mostly people who only recently got low back pain that isn’t bothering them very much. These are exactly the kind of people I would expect to just get better anyway, regardless of how you treated them. The lack of true effect of spinal manipulation for acute low back pain was recently confirmed by researcher (and chiropractor who has manipulated a lot of spines) J. Michael Menke found when he ran the statistics on spinal manipulation, finding:

  • “96% (81/84) of acute pain improvement in the first 6 weeks was unrelated to treatment”
  • “Attention placebo nearly doubled the pB [probability of recovery] shown in the difference between attended and unattended physiotherapies…”
  • “Acute pain treatment evidence never exceeded sham”
  • “More research is not the answer. That which is already known about SMT for back pain is quantifiably all that is worth knowing.”

The inability spinal manipulation to beat out sham treatments for acute low back pain was also confirmed in the Cochrane review, again, with the main author being a chiropractor. So come on PTs, catch up!

Conclusion aside, I thought it was a great paper, but when you go into your physical therapy clinic, conclusion is everything. Much of the paper I couldn’t say better myself, but then the authors go on to talk about future directions, saying that more research is needed to understand the mechanisms through which spinal manipulation works, to which they all seem flabberghasted. Well, I have one idea that oddly wasn’t mentioned once in the paper…

  • It starts with a “P”
  • It rhymes with “lacebo”

That being, the positive benefits you all see with spinal manipulation, it’s in your head, and/or it’s in your patient’s head. It’s placebo effect! Barely propped up by poorly controlled studies and likely a fair degree of publication bias. Patient expectations likely are a factor, and it’s lot easier to sell a patient on ideas that make sense rather than some nebulous general effect. Section 3.1 about segmental treatment was good science, it made sense, and unfortunately clearly pointed away from spinal manipulation really fixing anything. If it went the other way, I’d be cracking spines.

Thanks for reading my blog. If you have any questions or comments (even hostile ones) please don’t hesitate to ask/share. If you’re reading one of my older blogs, perhaps unrelated to neck or back pain, and it helps you, please remember Spinal Flow Yoga for you or someone you know in the future.

Chad Reilly is a Physical Therapist, obtaining his Master’s in Physical Therapy from Northern Arizona University. He graduated Summa Cum Laude with a B.S. Exercise Science also from NAU. He is a Certified Strength and Conditioning Specialist, and holds a USA Weightlifting Club Coach Certification as well as a NASM Personal Training Certificate. Chad completed his Yoga Teacher Training at Sampoorna Yoga in Goa, India.

4 thoughts on “Spinal Manipulation in Physical Therapy, Death Throes in Research”

  1. Hi Chad,

    I’ve had 2 discectomies at l4-l5 spread 3 years ago and 6 years ago respectively. Spent time with Dr. McGill post first surgery to reprogram my general day to day movements, it was an amazing experience and I use his training and movement techniques daily. I’m a former high performance water polo player. The back issues forced me out of that sport, and Dr. McGill was opposed to me spending any real time in the water from a fitness perspective as he felt the lack of a gravity based environment was working against me, or that at least if I only have so many hours per week to keep fit, that spending it on land vs the water was the wiser option.

    Getting to my question here, I continue to swim masters (yes I ignored him on this point), and train in the gym as well. The masters swimming is a passion, I don’t compete, afraid to go full sprint/explode off the blocks/walls, but I train relatively hard and am in pretty good control of my stroke/body in the water. What is your opinion on swimming – specifically front crawl (I avoid fly and breast because of the flexion/extension) as it relates to my injuries and relative sensitivity in that area of my spine? I feel as though I do a good job keep my spine neutral while rolling from side to side, but am concerned about sheer forces and other potential mechanisms for further injury. Many therapists say “go swim, it’s the best thing”, but they don’t necessarily understand the mechanics involved…


    Michael Gordon

    • Hi Michael,

      That’s cool that you were treated by Stuart McGill! My rehab approach is heavily influenced by McGill’s studies.

      The thing that worries me a bit about your story is that (if I understand you correctly) you had a 2nd discectomy even after training with McGill. It’s my understanding that he doesn’t normally treat patients unless they meet stringent requirements, as his time is generally taken up with research and education. Such that when he does see people it is usually them flying in to his lab in Waterloo, for which I would imagine few people can stay for extended periods of time. Such that he might teach you everything you need to know, but it might be more information than you can take in and assimilate in a short time period. For example with my back pain patients I give them my general spiel about increasing fitness, improving static postures and improving spine awareness/motor control during dynamic activities and it all only takes a few minutes to say and a few hours to show. However, it can take weeks for my patients to truly learn those techniques to the point they always practice them, such that when the reach down to grab a dumbbell off the floor they are aware enough to do it with a neutral rather than flexed spine. Or they may do all their exercises great, move well in my gym, and then go work 10 hours at a computer job with a poorly fit chair, thus sitting in sustained spine flexion. So if you are still having symptoms there is probably something still causing them even if most of what you are doing is correct.

      Moving on to your question, I’m not an expert with regards to swimming, but I did a quick PubMed search on swimming and low back pain and saw that elite swimmers are at higher risk for lumbar DDD. However it sounds to me like you are taking adequate steps to remove the damaging stresses of swimming from your current swimming routine. I expect it is the flexion/extension of the spine that causes the most damage, with perhaps rotation coming in second and when I look at the front crawl I expect that would be one of the safer strokes. I would think the buoyancy of the water would in fact minimize shear stresses, in comparison to most exercises so I wouldn’t be concerned their. So I would say if you are currently swimming pain free, to keep it up, as I imagine it’s great cardiovascular/aerobic exercise.

      The only downside with the swimming as you have modified it, would be if you were doing it to the exclusion of land based training. As weightlifting with good technique not only strengthens and builds muscular endurance, it also helps one practice good motor control to help prevent further injuries down the road. So while I wouldn’t think the swimming you are doing now is bad for your back, I just don’t think it is doing all the good things for your back that it probably needs, so if I were you I would just want to include a total body strength training program 2-3 times per week. The basic weight training program I work my patients toward is in a short video on my back pain page. I find EMS to the core muscles helps a lot with back pain, which you see being performed in the video as well.

      I hope that helps, and let me know if you have other questions.

  2. Hi Chad,

    Firstly, a big thank you for the detailed response.

    I don’t want to overstate my visit with Dr. McGill. To be clear, I’m a former national team water polo player up north in Canada, and reached out to him to see if he could assess my situation and help. My visit was about a 3-4 hour one, he actually followed me around campus, watching my habits, and then we hit the gym. As a result, I’m ultra particular about all my movements, lifting, sitting, opening doors, getting to and off the floor, etc. it was an eye opening experience, I corrected plenty of bad habits.

    As for your thoughts on the swimming, I found similar research results. I think you’ve nailed it, I really do need to up the gym work and keep the swimming to maybe once a week.

    I’m my own worst enemy in the pool and the gym because of my hunger to improve, the inevitable strength gains always seem to lead me to a place where I end up hurting myself again. The gym is a slippery slope for me. My ground/core routines are all McGill influenced (bird dog, side plank, stir the pot). I squat with low weight and good form, do some bench, seated row, and some other stability work. I use the elliptical as my cardio machine, doesn’t bother my back at all- but as a former elite athlete, I get very bored and lose motivation with that routine. Any other team sport/fun training you can suggest to keep my fitness levels good with a fun component that would be relatively safe for my back? So many adult leagues around of various sports, I’m just afraid to hurt myself again….

    Thanks so much for your time,


    • That’s interesting about McGill watching you in your normal environment. I was at one of his seminars and he told a story about a guy who was repeatedly getting left side lumbar herniations. He said after watching him for 5 minutes in his office he figured it out. The guy’s phone was on the far right of his desk and it rang incessantly, causing him to flex his spine combined with a twist to the right every time he picked up and hung up the phone, hence all the disc herniations back left. So there is something to be said about seeing a person in their environment.

      I’ll use a lot of the same exercises you listed as well as some others that I haven’t seen McGill use but are still in principle with his research findings. Romanian Deadlifts (RDLs) are probably my favorite, but I like standing cable rows and presses a lot to work core chest back and arms together. Lat pulls, DB curl and presses, and maybe some machine based exercises that may not be ideal for spine rehab, but might let you really “push yourself” but not over stress your discs. I’d definitely stay away from all ab machines, and leg presses I would only do one leg at a time. One thing I do with all my back pain patients that is strengthen the core with EMS. I got that from another Canadian Charlie Francis, for which I basically take the EMS parameters he used for track and field and apply them circumferentially around the core. With the right machine, pads, settings and parameters it’s way more intense than even stir the pot, and my patients almost universally agree it substantially cuts and often eliminates any back pain they have.

      Also I completely understand what you have to say about wanting to compete at something without jacking up your back. The shooting sports (I did IPSC) don’t offer a lot in way of fitness, but they are challenging and relatively low stress on the body (I have a bad shoulder that stopped me from Olympic weightlifting that did great with IPSC). Intermittent fasting gives a lot of energy, fat burning, and general health benefits similar to aerobic exercise and leaves you time to spare.


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