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A problem for manipulators
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A problem for manipulators - July 24, 2002 3:46:00 AM
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Barrett
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From: Cuyahoga Falls, Ohio
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The following description of a study from a recent issue of “Clinical Biomechanics” was provided the Supertraining list by Mel Siff.
The ability to translate manual force to target structures in the body has long been assumed possible by anyone using coercive technique. This study seriously questions this assumption.
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Clin Biomech (Bristol, Avon) 2002 May; 17(4):297-303
The frictional properties at the thoracic skin-fascia interface: implications
in spine manipulation.
Bereznick DE, Kim Ross J, McGill SM.
Objective. To assess the friction at the thoracic skin-fascia interface to
determine the potential reaction force vectors during thoracic manual
therapy.
Design. A basic in vivo study of human subjects, documenting the frictional
properties at the interface between the thoracic skin and underlying fascia.
Background: Chiropractors, and other spine manipulative therapists, during
thoracic manipulation have been attempting to apply force vectors to spine
tissues in specific directions in addition to those applied normal to the
skin. For obliquely applied forces to be directly transmitted to the
underlying vertebrae, either friction is required at the skin-fascia
interface or the applied force must "hook" on a bony process.
Methods. Subjects were placed in the prone position with the thoracic skin
exposed. The posterior thoracic region was loaded with normal forces,
incrementally from 125.3 to 392.9 N. The interface between the load and the
skin was either a plexiglass plate or modelled hands. A force was then
applied to either apparatus in the cephalad direction. The applied forces
and corresponding displacements were measured using a load cell and an
optoelectronic camera system, respectively. Chiropractors then performed
actual thoracic manipulation to determine if they could maintain their
location of contacts (spinous process/transverse process) on the underlying
vertebra.
Results: Each of the subjects exhibited negligible friction between the
thoracic skin and underlying fascia for both the plexiglass and modelled hand
contacts. Furthermore, in each case, the apparatus travelled a distance
greater than that between two transverse or spinous processes without showing
an abrupt change in the slope of the force-displacement curves. The hands of
chiropractors performing thoracic manipulation travelled a similar distance
during the dynamic thrust.
Conclusions: The skin-fascia interface over the thoracic spine exhibits
negligible friction. Therefore, the reaction force from a thoracic vertebra
will be normal to the overlying skin. Furthermore, the data show that the
ability to "hook" either a thoracic transverse or spinous process in the
superior-inferior direction during a manipulative thrust may be greatly
over-rated.
Relevance: During thoracic spinal manipulation, one cannot direct a force
vector to a thoracic vertebra at a given angle by simply directing their
thrust in that direction.
Any response?
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Re: A problem for manipulators - July 24, 2002 4:50:00 AM
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PTupdate.com
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Very interesting study, and with results that do not really surprise me. This is perhaps the reason why Mulligan advocates "taking up the slack" in the thoracic tissue prior to mobilization or manupulation. I guess palpatory skills come into play here, along with results. If someone has a rotated thoracic vertebrae, and one performs the skill, and normal alignment is obtained, I guess it could be assumed the force/thrust vector was appropriate. I guess the next step would be use of imagry, either radiographic or ultrasound to determine if the levels one is attempting to mobilize are truly the ones moving during the technique.
Duffy [URL=http://www.PTupdate.com]www.PTupdate.com[/URL]
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Re: A problem for manipulators - July 24, 2002 5:31:00 AM
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Barrett
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From: Cuyahoga Falls, Ohio
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John,
I was manipulating the thoracic spine for years before anybody even heard of Mulligan and was always told to "take up the slack" one way or another.
If imaging has ever revealed correction of vertebral position following manipulation it's news to me, and, of course, this type of research has been readily available for many, many years.
The bottom line is that we have a study indicating that moving the vertebra through the skin is rather like trying to move a table by pushing on the tablecloth. This is the issue, not whether or not manual care is helpful in some way.
A chiropractor responding to this on the Supertraining list asked, "Who says that (movement of the vertebra) is what chiropractors say that they do?
I can't believe he asked that.
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Re: A problem for manipulators - July 24, 2002 8:18:00 AM
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EWDC CSCS
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Barrett,
An interesting post which comes as no suprise.
"Relevance: During thoracic spine manipulation, one cannot direct a force vector to a thoracic vertebra at a given angle by simply directing their thrust in that direction. Any response?"
Sure, one cannot identify a specific "dysfunctional" vertebral level nor fixation in any given plane of motion via palpation with any reliability (let alone correct it). It seems that the more current research suggests that manipulation can have beneficial (or influential) effects regardless of line of drive.
P.S. Can you direct me to this Supertraining list that posters keep referring to?
[This message has been edited by EWDC CSCS (edited July 24, 2002).]
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Re: A problem for manipulators - July 24, 2002 10:45:00 AM
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Barrett
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From: Cuyahoga Falls, Ohio
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I'm wondering if your opinion about the lack of reliability of palpation is commonly shared in the chiropractic community. Might I conclude that the skill normally spoken of with spinal manipulation, which I assumed was mainly about making it specific, is unnecessary or overrated?
Go to [URL=http://groups.yahoo.com/mygroups]http://groups.yahoo.com/mygroups[/URL] to subscribe to Supertraining.
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Re: A problem for manipulators - July 24, 2002 11:46:00 AM
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EWDC CSCS
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Barret,
Everyone in my graduating class was taught that motion palpation has little to no interrater reliability. I'd say that a significant portion (majority) of our profession knows this. I'm speaking off the top of my head here, but I believe research has shown good agreement (with palpation)within 1 or 2 segments either way. (no surprise I guess)
In regards to manipulation, there is some interesting research regarding specific vectored manipulation in the upper cervical spine. I'm skeptical of this research, but it is interesting information none the less. I'll offer a couple of possible explanations regarding the delusion of specificity.
1) I generally don't believe that any manual therapist can find and treat a "specific" dysfunctional vertebra. With a significant amount of experience, however, some practitioners may be capable of finding dysfunctional "areas" in the spine through palpation and can, at times, treat these areas effectively.
2) Expert manipulators may not be any more specific in their thrusts, but much less abrasive. Therefore, a decreased level of resistance coupled with an increase in the comfort of the procedure may lend both practitioner and patient a false sense of specificity.
Thanks for the link.
[This message has been edited by EWDC CSCS (edited July 24, 2002).]
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Re: A problem for manipulators - July 24, 2002 12:54:00 PM
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Barrett
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From: Cuyahoga Falls, Ohio
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Thank you, whoever you are.
Two questions:
Do the other chiropractors looking on here agree?
Have I misnamed this thread? Is this study no problem at all?
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Re: A problem for manipulators - July 25, 2002 6:39:00 AM
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mcap
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Barrett:
Excellent thread. However, I am dismayed by some of the responses. When someone poses such a question the response should be.....should we be doing this at all???? Instead.....we always tend to look for reasons why something works with no intention of considering not using the methods.
Manipulation, and manual therapy in general have A LOT to prove. Yet....they are considered the cornerstones of orthopedic care.
mcap
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Re: A problem for manipulators - July 25, 2002 7:40:00 AM
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Barrett
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It's been 48 hours since the study appeared on the Supertraining list and 24 since it arrived here. So far just two replies from chiropractors.
I think this is a symptom of something but I'm not sure how to say what it is just yet. I'll probably think of something eventually. Let's go another day or two and see what happens.
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Re: A problem for manipulators - July 25, 2002 11:25:00 AM
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Bournephysio
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I have attempted to write a couple of responses but have thrown them away. There are many different issues covered by this thread. I'll try to keep it to a couple.
mcap: Why do you want to throw away manual therapy based on this study. Many techniques in medicine have been used without knowing why they worked. A quick search on pubmed using spinal manipulation efficacy reveals a bunch of studies. The general theme is that spinal manipulation seems to be effective for spinal musculoskeletal conditions and not effective for medical conditions. The fact that there are positive studies at all is pretty amazing since we don't know how to diagnose back problems and spinal manipulation has been based on bogus theories in the past.
This study does not really effect my treatments very much. I do not rely on skin friction to bias a manipulation towards flexion or extension. In roll down techniques you can flex/ext side flex and rotate the tsp to bias the manipulation. In standing and sitting techniques gravity produces the sup/inf force vector and the towel you place against the spine produces the ant/post force vector.
The biggest effect this study has on my practice is that it suggests that joint glides are not valid. I have suspected this for some time and would suggest the differences we feel are because of muscle tension. Reliability is a whole other issue which I'll try to write about later. Needless to say you shouldn't be relying on one test to base your treatment.
Doug
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Re: A problem for manipulators - July 25, 2002 11:42:00 AM
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Barrett
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Doug,
Effectiveness is not the issue nor was this study about that. It was about what actually happens to which tissues when manipulative technique is applied to the thorax. What do you think it says about that?
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Re: A problem for manipulators - July 25, 2002 1:24:00 PM
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Bournephysio
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From: Calgary
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The way mcap worded his response I thought he was questioning its efficacy.
As for this study, it basically says in prone thoracic manips, the only force transmited to the vertebrae will be from a straight posterior to anterior direction. Thus the manipulation will likely only gap the facets of the vertebrae being pushed under the vertebrae above. This is not good for someone that thinks they are correcting bone position unless they think the bone will settle in the right position after the manip. There was a good RSA (highly accurate) study looking at si joint position after manipulation. They found no change in position.
Spine 1998 May 15;23(10):1124-8
Manipulation does not alter the position of the sacroiliac joint. A roentgen stereophotogrammetric analysis.
Tullberg T, Blomberg S, Branth B, Johnsson R.
I believe that there is growing evidence that the effects of manipulation are neurophysiological. The same people who did this study published something on emg and manipulation. As EWDC alluded to you don't even need to get the correct joint to get a response. It also explains how chiros who only manip the upper Csp can have an effect on different areas of the body. Cervical proprioceptors probably have a large influence on the vestibular motor system and thus on muslce tone in the body.
Doug
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Re: A problem for manipulators - July 25, 2002 4:01:00 PM
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mcap
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Bourne:
I would never make a decision based on one study. What I am asking however is that we take a hard look at what we are doing. Some of the PTs (particularly down under) are doing that.
However, I have yet to see any convincing evidence that maniupulative therapy has anything more than a short term benefit for low back pain - the condition for which it's been most extensively studied. Iv'e seen an odd study here and there but mostly Iv'e seen efficacy for acute pain only and even then - short term. In terms of the extremities I have seen very little. Yet if you aren't doing manual work on the extremities, you are looked down upon. Furthermore, I think if we are not quite sure what is going on.....we should at least pause a bit.........
I know that this may get me in trouble.....but if you really want to perform manipulation so much then many PTs would have been served better by a career in chiropractic. This is not to say that PTs can't use it....and some do very well.....but I just would like to see orthopedic physical therapy move away from it sometimes.
This is heresy........I know.......fire away...... [IMG]http://www.rehabedge.com/forums/smile.gif[/IMG]
mcap
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Re: A problem for manipulators - July 25, 2002 4:05:00 PM
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Barrett
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Doug,
I certainly agree that neurophysiology comes closer to explaining the effects of manual care than any biomechanical theory ever has.
It follows that seeking to enhance that sort of response and working hard to interpret what the patient reports and what we can measure from that perspective would be the most reasonable way to approach care. This is what I've tried to do since abandoning manipulation years ago. It seems to me that if my own ideas about therapeutic response are correct, then the mechanical ones aren't. I don't think the postmodern "everyone's right" attitude is applicable in medicine. This study doesn't validate what I say (that work is elsewhere) but clearly it poses a problem for those who claim to gain a therapeutic response by stretching connective tissue or putting bones back into the "right" position.
Is this why they remain silent?
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Re: A problem for manipulators - July 25, 2002 5:38:00 PM
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EWDC CSCS
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Barrett,
While some of the old timers in the chiropractic profession still adhere to the "BOOP" theory (Bone Out Of Place), most chiropractic schools teach that this notion is utter nonsense.
Although a large percentage of chiropractors still view the effects of manipulation biomechanically ie. as a means of breaking up capsular adhesions, freeing up possible meniscoid entrapments etc. the focus seems to be shifting towards manipulation as a means of stretching the proprioceptor dense musculature of the intersegmental muscle groups.
I share the view with you, that ultimately, the neurophysiological model may explain many of the results that chiropractors see clinically.
[This message has been edited by EWDC CSCS (edited July 25, 2002).]
[This message has been edited by EWDC CSCS (edited July 25, 2002).]
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Re: A problem for manipulators - July 26, 2002 6:32:00 AM
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mcap
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would agree that manipulation produces more of a neurophysiological effect than biomechanical. So....two questions???
1. Do we need to use so much force if this is indeed what is happening?
2. Are these effects short term only regardless of the amount of force used. I have no problem beleiving the short term efficacy but long-term and lasting????? Not sure.
mcap
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Re: A problem for manipulators - July 26, 2002 6:34:00 AM
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mcap
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By the way.........I have long suspected that McKenzie exercises also have more of a neuro than biomech effect. So...under that rationale, it becomes increasingly difficult for me to take patients to end range if you can get the effect with less drastic movements. IE........stay with retraction instead of traction, retraction, extension and rotation.
mcap
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Re: A problem for manipulators - July 26, 2002 6:58:00 AM
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Barrett
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From: Cuyahoga Falls, Ohio
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It is truly gratifying to see after all these years that people are finally coming around to my way of thinking (ha,ha).
mcap, your question about the use of force was to be my next. Isn't it true that physiologic reaction grows with a decrease in stimulation (Arndt-Schultz's Law)? Shouldn't this inform our methods of care before we begin to employ them?
This is exactly the issue that led to one of the shouting matches I had with Robin McKenzie years ago.
Ahh...good times
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Re: A problem for manipulators - July 26, 2002 10:28:00 AM
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Bournephysio
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mcap: I agree that we always need to look hard at what we do. Not only do they have a good research base down under but they also have a high concentration of manual therapists. Although one of my previous instructors thought that Vancouver had the largest concentration of manual therapists (I believe that Barrett knows Jim).
I haven't looked at the research in depth. Clinically some patients are practically cured with one manip. Others gain range but come back the next day "locked" again. Manipulation can do wonders for muscle activation as well. I think that before we get really good studies we need to be able to diagnose and assess better. I have found that mobilization and manipulation of the extremities to be very useful. Is there not a study showing the effectiveness of manipulation for tennis elbow?
Is short term pain relief not reason enough to use it? If you can gain pain relief and start and progress exercises earlier, is it not worthwhile?
There are still too many problems in the Chiropractic profession for it to interest me. Physiotherapy has a long history as manipulators so I don't see its use as inconsistant with physiotherapy. Manipulation is only one part of the entire treatment plan and not even the most important. As a physiotherapist it is just one more tool I can use whereas as a chiropractor it would be my central tool.
If you are manipulating you should not be using that much force. It is a small amplitude high velocity thrust. If it is set up properly and the force is applied correctly and specifically you do not need a great deal of force.
Even if the effects are neurophysiological, I don't think it suggests how much force we should be using or even where in range we perform a technique (although I'd NEVER take a neck to eor ext/rot/traction). Some receptors respond more to the speed of movement, some to force. Clinically, manipulation seems more effective than mobilization. I have been told that there is a study to support this for low back pain but I haven't found it (might not be published yet. possible authors: Padfield Binkley Stratford Chessworth) I haven't heard of the principle you stated Barrett. Do you have any references? I also believe that this doesn't mean we can forget the mechanics. The original injury is usually mechanical as is our treatment even if we are using it for neurophysiologic purposes. Often the end goal is also mechanical. For example gaining proper motor control (neurophys) to improve mechanical stability in an ACL deficient knee.
What do you think?
Doug
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Re: A problem for manipulators - July 27, 2002 9:09:00 AM
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EWDC CSCS
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Mcap,
[QUOTE]Would agree that manipulation produces more of a neurophysiologic effect than biomechanical. So...Two questions???
1. Do we need to use so much force if this is indeed what is happening?[/QUOTE]
That is the million dollar question. I don't think that anyone can answer your question with any certainty. My reply is that I am only as willing to use as much force as is necessary to benefit my patients. Manipulation is obviously a contraindication for many patient populations.
[QUOTE]2. Are these effects short term only regardless of the amount of force used. I have no problem believing the short term efficacy, but long term and lasting????? Not sure[/QUOTE]
Again, a tough question to answer. A patient with acute/subacute pain may experience dramatic short term relief in pain with manipulation, while their injury heals according to it's natural course.
Chronic patients are enormously more complex and until we gain a better understanding of chronic pain, I don't think you'll get an adequate answer. Although there is research suggesting the efficacy of manipulation for chronic back pain, personally, I think that an active approach to care should be utilized as opposed to a reliance on passive interventions.
[This message has been edited by EWDC CSCS (edited July 27, 2002).]
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