Do We Know What the Actual Mechanism of the Manipulation Is?

I want to thank the EIM staff for inviting me to post and participate in dialogue within the "manual therapy" community.  I am excited about participating in real evidence-based discourse and look forward to the many opportunities ahead to learn from all involved.

As a practicing chiropractic doctor since 1991, I thoroughly enjoy the manual aspect of practice.  I have enjoyed the multi-disciplinary approach and have learned how important it is to treat with evidence-based protocols.  As a PT student, I really appreciate the integrative importance of true physical therapy and the neurological and functional component I have learned thus far.  It is apparent that the effectiveness of the manipulation is real and continues to be supported in the research in select environments. 

We are continually learning new applications of manipulation in the management of musculoskeletal disorders.

I would love to read the comments on what is perceived as the mechanism of action of a manipulation on the joint and/or surrounding tissues.  What does the evidence support?

For starters, I have been intrigued with the following claims as learned in chiropractic school, but question the evidence to support such claims.  Chiropractic education teaches that a manipulation corrects a "subluxation."  It is this "subluxation" that continues to remain vague in its description.  Do the following 5 components begin to describe a musculoskeletal pathology which is positively influenced by a manipulation?  What do others think of the following?

1. Joint kinesiopathology is a term used to describe the abnormal movement and position of the  involved joint.

2. Neuropathophysiology is the resulting nerve system damage from stretched, impinged, or irritated nerves interfering with that nerve's typical function.  Does this result in inflammed nerve tissue?  Could this result in paresthesia?

3. Myopathology is defined as changes in muscle function due to abnormal joint movement, or changes to the nerves controlling the muscle function.  ASIDE:  Could Hilton's Law  apply here?

4. Histopathology refers to alterations in soft tissues (capsule, synovial membrane, synovial tissue), discs, ligaments, and changes in the blood and lymph supply caused by the joint dysfunction.

5. Pathophysiology is the fifth component describing the cumulative, degenerative damage over time to the bone and/or joint, as well as the organs and tissues of the body.

 

I think any of these areas could be objectively studied, though tedious to undertake.  I would love to hear what others think on how a manipulation may influence any one of the above mentioned components, provided the five components even exist.

 

Chris Baker

Comments

[Britt Smith]

Chris, great topic(s) to work on. My reading on the effects of manipulation point to mostly a neurophysiological effect: primarily muscle inhibition/facilitation and a hypoalgesia after manip. I haven't seen any compelling evidence for biomechanical changes.
Thoughts?
Britt

[Steve Young]

Britt,

I agree fully with you. Walter Herzog has done a significant amount of research in this area and demonstrated that there is muscle inhibition and facilitation that occurs quite distal to the site of manipulation (In one study, a consistant deltoid inhibition was found post sacroiliac manipulation) and this likely contributes to why non specific manipulation in the CPR is so effective.

Steve

[Jim Beazell]

Chris,
Interesting areas for research, although I am not sure we need to coin different terms for kinematics, neurodynamics, or hisology. Some of this research is being done and presented even now. I agree that the effects that I see clinically seem to be related to the neurophysiological effects of manipulation. We have done some pre/post manip fluoroscopy but very difficult to be consistent with view to verify joint changes.
We have,however, seen specific disinhibition of quadriceps with manipulation of the LS junction.
Look up arthrogenic inhibition in pub med for current thoughts on this subject.

Jim

[Jim Beazell]

Chris,
Interesting areas for research, although I am not sure we need to coin different terms for kinematics, neurodynamics, or hisology. Some of this research is being done and presented even now. I agree that the effects that I see clinically seem to be related to the neurophysiological effects of manipulation. We have done some pre/post manip fluoroscopy but very difficult to be consistent with view to verify joint changes.
We have,however, seen specific disinhibition of quadriceps with manipulation of the LS junction.
Look up arthrogenic inhibition in pub med for current thoughts on this subject.

Jim

[Jon Newman]

Hi Chris,

I'm curious why all the options you listed were pathologies when the CPR for manipulation seems to work best for those without signs of pathology.

I think it is a mistake to suggest that pain always signals pathology. I suspect that we encounter more irritative processes than destructive processes in our life times. I think spinal manipulation is likely to serve the former more so than the latter.

[Chris Baker]

I really do appreciate all the great comments thus far and the thought stimulating facts. As I continue to develop as a PT, I discover that terms I have been exposed to sometimes take on a different meaning between the professions, ie semantics. I apologize for that. When I refer to “pathology” I use the term to mean “a departure or deviance from the norm” (found Farlex Dictionary); or “The branch of medicine concerned with disease, especially its structure and its functional effects on the body.” (found Medical Dictionary). I do not mean to imply that a diseased state is present (ie arthritic), but that a “deviation from the norm” is present, as in joint dysfunction.

However, when we are able to dissect the mechanism of this very effective treatment on joint dysfunction, will we discover that the mechanism is purely mechanical, or is there any evidence of a “neurophysiological effect” as Britt and Steve have illustrated. If a “neuro” component is included, then would this be considered a “disease” state of the joint? If the joint is “diseased,” due to fixation, contracture, hypomobility, then would this lead to further changes in the synovial lining or capsule which may influence proprioceptor stimulation leading to further changes in typical movement patterns, or postural changes, or even muscular weakness?

I do agree that pain does not always signal a pathology, but does this mean that pain can be considered a norm? If pain is a synonym for inflammation, then is not inflammation alone defined as:
A localized protective response elicited by injury or destruction of tissues, which serves to destroy, dilute or wall off (sequester) both the injurious agent and the injured tissue.
It is characterized in the acute form by the classical signs of pain (dolor), heat (calor), redness (rubor), swelling (tumour) and loss of function (functio laesa).
Histologically, it involves a complex series of events, including dilatation of arterioles, capillaries and venules, with increased permeability and blood flow, exudation of fluids, including plasma proteins and leucocytic migration into the inflammatory focus. (see Medical Dictionary)
I do not think that joint dysfunction is always destructive on a large scale (although it is present in arthritic changes), I do agree that it is irritative. I would also agree that the manipulation is considered appropriate for the “irritative” stage of joint dysfunction as CPR defines, and probably not indicated in an inflamed arthropathy --- but what remains unanswered is, just what is occuring within the dysfunction to promulgate an alteration in function of the joint that results in the clinical findings which we see objectively to diagnose?
I will look up arthrogenic inhibition as you state, Jim. I really do appreciate your comments.

Good food for thought. Chris

I also apologize in that my comment here contains many links to websites which I can not figure out how to post. I will be more than happy to forward a Word document to anyone who would like to review. CB

[Britt Smith]

Aye, Chris, semantics is the game. Tim Flynn wrote and editorial about the problems with the language of manipulation, i.e. how we label the techniques and constructs we use. Most of us think and refer to technique biomechanically, FSR Right, up-slip, down-slip, rotational techniques, opening or closing techniques. Carl De Rosa has posed the question: Is it time for a new vocabulary of manipulation? Shouldn't we use terms that reflect what we are actually doing not some invalid construct?
Any thoughts?
Britt

[Jason Silvernail]

Chris-
You bring up good points, and quite an interesting topic.
I definitely don't think we should ever consider "pain" and "inflammation" as synonyms. In fact, as I see it, one of my primary jobs as a therapist is to determine whether someone's pain is mechanical, chemical, or both in nature. That really does help guide the treatment, and inflammation only accounts for chemical pain.

Britt-
While I agree that both Tim and Carl are right about changing the language away from the well-refuted biomechanical terms (which confuse operators and patients alike), there is another issue here.

The question "Shouldn't we use terms that reflect what we are actually doing not some invalid construct?" is the key one here.

Since we don't know what we are "actually doing", that makes changing the vocabulary a bit hard. :)

Hence the reason for Chris' post. If we agree that we don't know why it works, but only that it does in some circumstances, then what next? If it is indeed the effect of manipulation and not the tool itself that we are interested in, then perhaps we would be well served by exploring alternate means to that end as well.
J

[Britt Smith]

Jason,
I think we do know why we do manipulation: largely to relieve pain and restore motion/function. We don't know how or why it is effective in relieving pain or restoring motion, but we know it works (i.e. is effective). Different questions. Biomechanical explainations have always informed elaborate evaluation system and created certain 'biological plausibilities' for manipulation, which has informed 'buy-in' or belief in training practitioners, and vis-a-vis to treat the patients.
The question of mechanism (neuro-muscular) raises the issues about validity of the discriptive vocabulary (biomechanical).
Maybe we ought to use the language of faciliation/inhibition or 'PNF patterns' or such as more appropriate for the dialogue about technique.

I can raise many questions about manipulation:
Do we manip the painful segment? or
Should we rotate away from the painful segment? or
Should we first manipulate the apparently restricted segment, irregardless of pain or not? or
In responders, do you think the 'released' segment is more likely to hypomobile or hypermobile on re-assessment?????
May questions. Just some thoughts.
Britt

[Jason Silvernail]

I agree, Britt. Those are different questions. I was speaking about the mechanism part, not the effect part.

And i agree, I think our terminology needs to change to reflect the more likely neurophysiological mechanisms. But how are we to name the techniques then? If all we are doing is providing a neuromodulation / neurofacilitation treatment, then how many techniques do we need to know? Like most really interesting topics, it sparks more questions than it answers. :)
Thanks for the good discussion.
J

[Steve Jorgensen]

One thought on techniques and the need (or not) to have a variety in our toolbox: even if manipulation is "merely" neuromodulation and not a specific and predictable mechanical effect, there seem to be differences between people in the direction of thrust from which they will gain results. Of course, I am speaking from my own experience here, and I know that is low on the levels of evidence totem pole. It seems that some people do not respond well to a gapping or opening technique and then get relief from a closing technique. Of course, the problem then is how to predict who will respond to what, rather than having to just try one and then the other. I have tried to reason this out for myself, with mixed success, using assessment of muscle tone; attempting to be somewhat specific with the level(s)I think is (are) involved - not that I kid myself, at least not anymore, that this is always possible.
Anyone hae any thoughts on this?

Steve.

[Jason Silvernail]

That seems consistent with what I've experienced, Steve.

I used to try to find the restriction and manipulate into it to "force it" to close/open. I was about 50% successful. If it didn't help, I just flipped the patient over (if lumbar) or did the opposite technique, and then it magically worked. But again, not for every patient.

This is why the work on CPRs for this sort of thing that our esteemed colleagues have been doing is so important. I think for many techniques and conditions, the manual therapy approach is as much about trial and error as anything else. Those mechanical theories maybe were comfortable because they gave us reason to think it was more than blind luck (as far as direction and technique selection, etc).
Maybe that's a reason that for many people, those theories are so hard to give up.
J

[Chris Baker]

Howdy Jason. I think you are right about the pain issue. Yes, I agree that they are different, yet closely intertwined. Pain could be the result of a stimulus of the mechanoreceptor (ie Parcinian or Ruffini as in the capsule) which brings the patient in to see us in the first place. Inflammation would be the chemical component where one would observe tissue granulation and scarring I suppose. So if pain brings the patient in for treatment, then the mechanical joint dysfunction component would be amenable to the manipulation possibly. It is interesting to me how this concept seems viable (ie manips may reduce stimulation of mechanoreceptors by increasing tissue/capsule flexibility) but not well supported in CPR.

I agree that the neuro component does respond as well. Does neuro only include the nerve carrying the mechanical stimulus? Or does it include the reflexive response (somato-somato or somato-visceral or somato-sensory reflexes.) as well, which may accompany a dysfunctional joint? I think it does, which is why the manipulation has a neuro effect I believe. Maybe someone well versed n this aspect of CPR could chime in.

Britt

As far as unifying terminology, I don’t have an answer either. Manipulation captures what we do. And like Jason said, “If it is indeed the effect of manipulation and not the tool itself that we are interested in, then perhaps we would be well served by exploring alternate means to that end as well.” I really think that we are on the verge of discovering answers to many of these unanswered questions as research progresses in this area. I do think that the mechanism will begin to unfold as we further investigate its application and benefits. What I like about this dialogue is the different approaches and ideas which we each have learned and observed clinically. I am new to many of the therapist’s approach (2 years of school and work), however I have learned that the neurofacilitation is such a huge contribution.

Technique

As a chiropractor, I have been inundated with multiple techniques as to the mode of manipulation. As Steve states, I have observed different benefits based upon the approach and direction of the manipulation. I have been of the opinion that generally manipulate into the restriction – whether to close or open functionally. Coming from a practice where I predominantly manipulate for 14 years, I too have observed many wonderful results. I have observed that different techniques seem to have different effects – ie drop tables, Thompson, flex/distract, etc. and the specific direction or force has varying results.

So – back to mechanism. I do believe that we will learn more about mechanism while we learn more about the "pathology" which responds to the manipulation. I think the dysfunctional "cause" may inevitably rely upon scientific cellular studies, or neurotransmitter studies, or pre- / post- manip fluoro, or even neuro studies attempting to discern changes in stimulation and/or relative reflexes to further explain WHAT we are manipulating. This is why I enjoy research and the profession of manual therapy we participate in.

More comments. Chris

[John Ware, PT, FAAOMPT]

When a pt comes into my clinic with acute LBP who meets 3-5 of the CPR criteria, I may manipulate him or her. I may not if I have a "hunch" that the "lesion" is not "manipulable." This is an esoteric principle that I picked up from the British osteopath, Laurie Hartman, D.O., who has taught many PT's in the U.S. I'm not sure what the hunch is, or isn't, and furthermore, don't know if it's always correct. As we hear from some of the "old guard," who up to this point have been a bit mum on this CPR business, I think more about the "hunch" is going to come out. I like the idea of CPR's, but something about the described technique alerts my hunch, particularly when I apply the CPR to older pt's, who have not had a significant h/o LBP. I'm reminded of Dr. Stoddard's "warning signs," which were strongly emphasized during my residency training.
In my copy of the CPR study, descriptive stats include an age range from 18-59, but it's not broken down by age cohorts. Though age was not a significant predictor of success or nonsuccess, I wonder how many over 50 spines were actually manipulated? Of these, how many had a successful outcome? What's the statistical power w/in that age cohort? What about when you cross age w/ gender? I think about all the 50-59 y/o undiagnosed female osteoporotics out there. Then I get a bit concerned that PT student are learning the CPR with this technique. Bottom line: when in doubt, and the pt is over 50, trust your hunch not to manipulate.
John