PUZZLE & PARADOX 72

The effects of joint manipulation or mobilisation may not be as clearly
related to traditional explanations of their underlying mechanisms as
suggested by various therapists.

Most sports scientists, physiotherapists and athletes are very aware of the
various classes of mechanical ‘realignment’ of joints (including
manipulation and mobilisation) that are applied by physical therapists or
chiropractors. These twists, thrust, pulls or pushes of the spinal column,
in particular, are often accompanied by an audible ‘click’ or ‘pop’.

The professional therapists who apply this form of treatment attribute any
subsequent relief from pain or mobility symptoms to processes such as the
reduction of subluxations, stretching of connective tissue, the release of
nitrogen bubbles within the joint fluids, the realignment of joint surfaces,
nerve release and so forth.

This type of procedure is the central foundation of chiropractic and to
manipulative therapy in physiotherapy, with its users totally committed to
its effectiveness. Some long-term studies, however, indicate that joint
manipulation or mobilisation makes no statistically significant difference to
the rate or degree of recovery of the client from pain or malfunction. In
some cases, these procedures have resulted in far greater damage to the
patient, with periodic reports of hemiplegia, quadriplegia or exacerbation
of existing spinal damage appearing (frequently a result of inadequate
collaboration with medical, radiographic or surgical experts).

While the controversy between the merits and demerits of manipulative
procedures will no doubt continue to rage, this is not the main thrust of
this P&P. What appears to remain uncertain is the reason why these
procedures are successful in certain instances. All of the reasons
mentioned above need to be examined carefully before we can state
scientifically that there is a cause-effect relationship between any of them
and rehabilitation from back pain and/or dysfunction.

For instance, let us examine the contention that a quick, sharp thrust of
certain vertebrae will stretch the ligaments in that region and produce
greater mobility at that level. This presumes that a rapid movement will
cause permanent plastic deformation of the connective tissue, which happens
to be viscoelastic in nature. This means that rapid thrusts should evoke a
more elastic response from the appropriate vertebral ligaments, rather than
plastic deformation, which usually is a result of prolonged stretching above
a certain threshold level of strain in the tissues. So, if plastic
deformation is unlikely, this leaves only one other alternative, namely
tissue rupture, which is the last thing that any therapist wants.

However, all of this presumes that the therapist can produce sufficient
manual force to deform ligamentous tissue, which is highly unlikely, because
of its enormous mechanical tensile strength.

This immediately leads us to the hypothesis that many ‘back problems’ are
due to subluxations (small dislocations) of the vertebrae relative to one
another. We immediately have to ask if normal daily activities can
temporarily stretch enormously strong ligaments sufficiently to permit these
subluxations to persist for prolonged periods until the therapist
intervenes.

We have to examine the proof for the existence of these temporary
subluxations such as MRIs or CAT scans – is there unequivocal evidence to
show that ligaments (which are extremely inextensible) can be temporarily
stretched to allow adjacent vertebrae to stay dislocated relative to one
another? If so, then it will be interesting to carry out a biomechanical
analysis of the stresses and strains involved. It will be even more
interesting to understand how the slightly, but powerfully stretched,
ligaments manage to return to their original length along an hysteresis path
that shows no residual strain after prolonged stretching.

Even if one suggests that the subluxation or displacement that is reduced by
manipulation is the sum of tiny contributions from many vertebrae, it does
not eliminate the fact that ligament is very difficult to deform, especially
if subjected to a single sharp thrust.

What then of traction, that is probably used as widely as manipulation? Can
one state that traction stretches ligaments as well and relieves pressure on
nerves? Or is the idea of traction simply to overcome a persistent myotatic
stretch reflex which has temporarily forgotten to become inoperative or a
Golgi tendon reflex that has omitted becoming involved?

Possibly this would then offer a more rational approach to explain why
manipulation might relieve back pain or dysfunction. Such an hypothesis
would suggest that the muscles cause the ligaments to be pulled in a certain
direction, thereby producing and sustaining a subluxation. Of course, we
then have to examine how long a stretch reflex can remain operative and how
long a muscle can remain submaximally contracted. In the case of some back
pain sufferers, we might have to wonder at the impressive local muscle
endurance involved.

There are several other questions remaining regarding manipulation, such as
the cause of the ‘pop’ or click’. If it is indeed produced by the release
of air or nitrogen bubbles into the joints, then this would imply the
occurrence of cavitation, which is known to produce very detrimental shock
waves in engineering systems. If gas bubbles are released in the
cerebrospinal fluid, does this not imply the possibility of micro-shock wave
damage to structures in the spine, especially if manipulation is applied
regularly? Is there any evidence for the release of gas bubbles with
manipulation and, if so, are there any studies to show that they are
harmless artifacts?

Maybe the acute relief afforded in certain cases is more a consequence of
neural stimulation rather than mechanical realignment, caused by stimulation
of the nerves passing from the foramina of the spine. Would this also be a
reasonable hypothesis? Naturally, this would give us the opportunity of
invoking the ubiquitous placebo effect!

This P&P could be extended into the broader territory of deep transverse
friction, structural integration (‘Rolfing’) and so on to create a broader
base for examining the mechanical manipulation of the entire musculoskeletal
system. Indeed, this would probably be of enormous value in removing some
of the controversy associated with all of these procedures.

Comment on any of the issues raised by the above focus on manipulation and
mobilisation as currently practised by various therapists, quoting any
scientific studies which appear to support or disprove the value of these
procedures and the explanations presently given to validate them. Regarding
the mechanisms involved – Is it in the back or is it all in the head?

——————

Mel Siff
Denver, USA
Mel Siff Dot Com
Supertraining Twitter Feed

INTRODUCTORY NOTE

For newcomers to this forum, these P&Ps are Propositions, not facts or
dogmatic proclamations. They are intended to stimulate interaction among
users working in different fields, to re-examine traditional concepts, foster
distance education, question our beliefs and suggest new lines of research or
approaches to training. We look forward to responses from anyone who has
views or relevant information on the topics.

PUZZLE & PARADOX 126: SUBLUXATION PARADOX

We constantly hear from colleagues and some therapists that someone’s spine
or neck is “out of alignment” or that the bones in some or other part of the
body are “subluxated” (or held in a prolonged state of chronic partial
dislocation or “mal-location”). At the same time research informs us that
the ligaments and connective tissues involved with those joints are extremely
tough, only slightly extensible and resist deformation very powerfully.

Even outside the body in being tested in vitro, ligaments and fasciae have to
be subjected to considerable force to produce significant extension for even
short periods, so how is it possible for apparently resting levels of muscle
tension to produce sufficient force to maintain persistent “subluxation”?
Of course, if the connective tissues concerned are actually damaged or
herniated, then dislocation may be one of the well-known consequences, but if
the alleged deformation is not of that magnitude, then how can a “partial”
dislocation be maintained?

Naturally, the use of therapy to “release” the hypothetical tension assumes
that these viscoelastic tissues, despite prolonged imposition of tension,
display perfect hysteresis and return to their pre-pathological state
immediately after manipulation or whatever treatment is deemed to be
appropriate.

How can one reconcile these diametrically opposed views? Are there any
radiological scans or other studies which have confirmed the existence of
“subluxations” or low level connective tissue disturbances which allow
“partial dislocations” or “misalignments” to occur chronically, even though
powerful
muscles contractions from adjacent muscles may override the alleged chronic
tension produced by tissues which are hypothesized to maintain those
alleged displacements?

———–

Mel Siff
Denver, USA
Mel Siff Dot Com
Supertraining Twitter Feed