As the scope of physiotherapy widens, we are increasingly faced with new
clinical challenges, particularly with those involving neuropathic pain. We are
currently receiving in our clinics a higher number of patients with some form
of central or peripheral sensitization, thus, we face the task of having to
assess, diagnose and treat very difficult conditions. Our professional training
did not equip us with any tool that could assist us when dealing with this kind
of patients (except for some pain assessment charts like McGill’s and so on),
and all we have been able to do is to apply some type of general manual
treatments, very softly, use acupuncture if tolerated, and work out some
exercise plan that may include hydrotherapy and movement meditation (Tai-Chi, Qi-Gong,
etc.) hoping not to cause any more pain. In this situation we find ourselves in
the same place as the physician who does not know either how to deal with these
patients, and is forced to treat them with anti-depressants and painkillers to
the best of his/her abilities. Fortunately, these neuropathies are no longer
considered psychosomatic and are gradually being seriously addressed. An
increasing amount of research is starting to be directed towards achieving
better models for the understanding of these conditions.
Recent developments in pain research have prompted a whole range of
theories and explanations which can be put to use in our physiotherapy
practice. For instance, our current understanding of the role of
neuroplasticity in pain neurophysiology, following the experiments of
Ramachandran with phantom limb patients and other neuroscientists, has
encouraged physiotherapists to employ mirror therapy, not only to amputees but,
for example, to stroke [1] or Complex Regional Pain Syndrome[2] patients, with successful results. Plasticity in pain has also been
explored for treatment using spinal manipulative techniques[3] that target sensitization mechanisms. But, despite these
improvements, we are still lacking a satisfactory “protocol” for pain
assessment and treatment that may target the complex spectrum of neuropathic
pain. For this reason, I wanted to highlight by means of this post, the
interesting tool developed by a couple of Australian colleagues which I think
will definitely be of assistance and will improve our practice.
Lester E. Jones and Desmond F.P. O’Shaughnessy recently published an
article in Physical Therapy (actually the article is still
in-press although published on-line and accessible via Science Direct) where
they propose an integrative model for the assessment of pain based on the
Neuromatrix Theory of Pain (by Melzack) [4] and neuroplasticity called The Pain and Movement Reasoning
Model[5]. This
humanistic/holistic model combines the physiological, emotional, cognitive and
social inputs in the neurophysiological process. In order to integrate these
aspects, they propose a triangular structure of three categories: central,
regional and local factors, which have to be addressed and explored in order to
diagnose and implement treatment. The first category called Central
Modulation, is integrated by three sub-categories: the predisposing
factors in the patient (general health, past painful experiences, and gene
expression), the prolonged afferent input (that is, the prolonged noxious
stimuli), and the cognitive-emotional-social state (including thoughts, beliefs
and emotions as well as the current social context of the patient). This
category, for instance, can give information on how sensitivity is being
modulated, and can re-direct treatment towards psycho-neuro-immunological
retraining approaches. The second category is called Regional
Influences Category and includes three sub-categories: Kinetic chain
(bio-mechanics), patho-neuro-dynamics, and convergence (referred pain). This
category gives information on where connective tissue, joints or muscles are
altered, thus, providing guidance for manual therapy and exercises regionally.
The last category is Local Stimulation Category and comprises the
sub-categories of chemical stimulation (that is, chemical sequalae associated
with tissue damage), and mechanical deformation. By this category, for
instance, treatment could be directed towards managing inflammation, rectifying
tissue alterations, and addressing local mechanical influences.
These three categories are arranged in a triangular structure which is
filled by a grid. The idea is to evaluate the patient and place the results of
this threefold structure in some space of the grid. This placing will give
information about the location where pain is more relevant and thus re-direct
treatment accordingly. Ongoing assessment and diagnosis will alter the position
in the grid and further inform about the changes that are taking place and
where the pain condition is being re-focalized so as to modulate treatment
consequently.
As the purpose of this blog is to reflect on theoretical issues concerning
physiotherapy, it would be interesting to review this model further, but in
order to do that, I think it is necessary first to think more deeply about the
theories in which it is based on, specifically, the Neuromatrix theory of pain,
which leads to a reflection about the different models of pain in general. But
that will be a matter for another post, for the time being, I just wanted to
highlight the interesting work that is being done in trying to protocolize and
improve the diagnosis and treatment of neuropathic pain from a
physiotherapeutic point of view by using the current advances in neuroscience.
[1] H. Thiemea, J. Mehrholzc, M. Pohld, J. Behrensb, C. Dohlee. (2013).
Mirror therapy for improving motor function after stroke. Journal of the Neurological Sciences. Volume 333, Supplement 1. p. 573.
[2] Samaa Al Sayegha, Tove Filén, Mats Johanssonc, Susanne Sandströmd, Gisela
Stiewee, Stephen Butlerf.(2013). Mirror therapy for Complex Regional Pain
Syndrome (CRPS)—A literature review and an illustrative case report. Scandinavian Journal of Pain 4.
p.p.200–207.
[3] Robert W. Boal and Richard G. Gillette. (2004). Central Neuronal Plasticity, Low
Back Pain and Spinal Manipulative Therapy. Journal
of Manipulative and Physiological Therapeutics. Volume 27, Number 5. p.p.
314-326.
[4] The neuromatrix theory of pain proposes that “pain is a multidimensional
experience produced by characteristic “neurosignature” patterns of nerve
impulses generated by a widely distributed neural network—the “body-self
neuromatrix”—in the brain.” (Ronald Melzack. (2005). Evolution of the
neuromatrix theory of pain. The Prithvi Raj lecture: presented at the third
world congress of world institute of pain, Barcelona 2004. Pain Practice 5. p.85.) As Melzack continues to explain in his
paper, the neuromatrix theory “proposes that the output patterns of the
body-self neuromatrix activate perceptual, homeostatic, and behavioral programs
after injury, pathology, or chronic stress. Pain, then, is produced by the
output of a widely distributed neural network in the brain rather than directly
by sensory input evoked by injury, inflammation, or other pathology. The
neuromatrix, which is genetically determined and modified by sensory
experience, is the primary mechanism that generates the neural pattern that
produces pain. Its output pattern is determined by multiple influences, of
which the somatic sensory input is only a part, that converge on the
neuromatrix.” (Ibid.)
[5] Lester E. Jones and Desmond F.P.
O’Shaughnessy (2014). The Pain and Movement Reasoning Model: Introduction to a
simple tool for integrated pain assessment. Manual
Therapy xxx. p.p. 1-7. (in-press)
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