Major Models and Hypotheses of Chiropractic Subluxation: II. Neurologic Models

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Major Models and Hypotheses of Chiropractic
Subluxation II. Neurologic Models
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II. Neurological Models

• Nerve compression
• B. Dorsal Root Ganglion compression
• C. Spinal Cord compression/traction
• D., E., F. The Reflex Models

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Reference

• Sato, A.
• Chapter 8 Spinal Reflex Physiology
• Swenson, R.
• Chapter 9 Clinical Investigations of Reflex
  Function
• in
• Haldeman, S.
• Principles and Practice of Chiropractic, 1992

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Reflex Models

• Can be understood as different combinations of
  communications (reflexes) between somatic and
  visceral structures
• 1. Somato-somatic (aka somato-motor)
• 2. Somato-visceral (aka somato-autonomic)
• 3. Viscero-somatic (aka viscero-motor)
• 4. Viscero-visceral (not currently discussed as
  subluxation model no somatic component)

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Reflex Models

• Somato-somatic (aka somato-motor)
• local spinal effects of subluxation- muscle
  hypertonicity/imbalance, fixation, etc
• Somato-visceral (aka somato-autonomic)
• subluxation effects on visceral function
• Viscero-somatic (aka viscero-motor)
• visceral cause/perpetuation of subluxation

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D. Somato-Somatic Reflex Hypothesis (aka
somato-motor proprioceptive insult)somatic
afferents somatic efferents
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Somato-somatic Reflex Model

• Korr and early researchers felt that
  richly-innervated somatic tissues in and around
  the spine were the source of afferent
  bombardment of neurologic signals, leading to a
  state of hyperstimulation, or facilitation
• This state was considered to be
  self-perpetuating, leading to reflexive errors in
  postural muscle tone and other somatic structures
  involved in posture and locomotion

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Somato-somatic Reflex Model, cont.

• Seaman and others currently propose that
  nociceptive neurons are the afferents which
  produce this facilitation. (nociceptive
  facilitation)
• Among the various effects are nociceptive spasm
  of isolated segmental spinal muscles which than
  do not act in coordination with the rest of the
  spine. (out of step, segmental consternation)

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Somato-somatic reflex
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• The disturbance in the cord is caused by
  distorted afferent impulse patterns from either
  (a) affected musculoskeletal tissues, (b) lesions
  of nerves, roots and ganglia due to irritation.
  Or both, preventing adaptive, appropriate
  responses.
• Korr

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Inflammatory Model of Facilitation

• Damaged skeletal tissues associated with SDF
  (segmental dysfunction) release vasoneuractive
  substances such as bradykinin, prostaglandin E2,
  substance P, histamines, etc., which facilitate
  neural pathways, including nociceptors. This may
  give rise to the initial stages of segmental
  facilitation of the spinal cord.

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INJURY
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• Once this facilitation occurs, despite the
  removal of the afferent source of stimulation,
  the abnormal reflex circuit itself participates
  in maintaining the symptoms, thus creating a
  cycle of increased output with any sensory
  input.
• Leach, 1994, p. 101

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• Activation of deep (type IV) nociceptive
  afferents from the involved joint tissues project
  polysynaptically to alphamotoneurones of the
  muscles related to the involved joints, thereby
  giving rise to abnormal reflex activity in the
  musclescontributing to further pain, and joint
  and muscle dysfunction.
• Terrett and Terret, Referred Posterior
  Thoracic Pain, Chiropr J of Australia 2002 32
  44

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• a positive feedback cycle of proprioceptive
  excitability may be triggered, refreshed and
  maintained within pain-signaling neurons by
  periodic nociceptive and non-nociceptive
  paraspinal input.
• Terrett and Terret, Referred Posterior Thoracic
  Pain, Chiropr J of Australia 2002 32 45

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Facilitation can result in a positive feedback
cycle, or a vicious circle
Input
Output
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The Deafferentation Concept

• Some authors suggest that an effect of spinal
  fixation/hypomobility associated with subluxation
  process may cause diminished afferent signals
  from somatic structures
• Primarily implicated are mechanoreceptors
  (especially types I II)
• CNS is therefore deprived of information needed
  for balance and coordination ataxia and
  dizziness can be clinical symptoms

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• Chiropractors dont take pressure off nerves-
  they put pressure on mechanoreceptors.
• Ninety-nine percent of all neurologic syndromes
  are related to deafferentation.
• F. Carrick, D.C.

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• Ninety percent of the incoming sensory
  impulses to the brain come from the joints and
  muscles. Thats why contracting muscles and
  moving joints have a profound effect on all
  neurologic function, which then affects every
  other system in the body.
• Gregory Malakof The Neurology Behind the Health
  Benefits of Yoga

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The Deafferentation Concept

• It is further known that mechanoreception affects
  the transmission of nociceptor information
• Nociceptive transmission can be modulated
  through gateway synapses in the basal spinal
  nucleus by peripheral (joint and muscle)
  mechanoreceptor (type I and II) discharge.
• Terrett and Terret, Referred Posterior Thoracic
  Pain, Chiropr J of Australia 2002 32 44

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• it is proposed that decreased mechanoreceptor
  input associated with decreased or restricted
  joint mobility (hypomobile subluxations) causes
  increased perception of pain.
• Terrett and Terret, Referred Posterior Thoracic
  Pain, Chiropr J of Australia 2002 32 44

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Somato-somatic reflex model Is it increased
afferentation, or decreased afferentation?

• It is both increased nociceptor traffic and
  decreased mechanoreceptor signals could be
  jointly referred to as somatic dysafferentation
• Reflexive effects of this cause altered postural
  muscle tone or imbalances, leading to errors in
  posture and coordination and segmental somatic
  dysfunction which is self-perpetuating
• There may also be increased pain perception
  because of pain gate modification

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• Somatic Dysafferentation
• Increased nociception
• and/or
• Decreased mechanoreception

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What to Tell Patients (regarding somato-somatic
reflexes)

• Abnormal motion and alignment of spinal joints
  can cause persistent muscle tightness in and
  around the spine this can be a factor in spinal
  stiffness and pain
• Balance and coordination can be affected by
  abnormal signals coming from spinal joints
• This becomes a vicious cycle a subluxation is
  self-perpetuating i.e its effects cause it to
  become worse

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What to Tell Patients (regarding somato-somatic
reflexes)

• A subluxation can be like a bad habit easily
  started, and hard to break. It can take
  repeated adjustments and consistent work to
  achieve full correction of subluxations.
• Loss of spinal motion can cause increased
  perception of pain consequently, improved spinal
  motion can help relieve pain.

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Article of Interest

• Bolton, P
• Somatosensory system of the neck and its effects
  on the CNS
• JMPT 218 Oct 1998

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E. Somato-Visceral Reflex Hypothesis
(aka somato-autonomic)so
matic afferents visceral efferents
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New Text of Note

• Masarsky and Masarsky, 2008
• Somatovisceral Aspects of Chiropractic An
  Evidence-Based Approach

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Somato-Visceral reflex model

• Somatic dysafferentation can reflexively change
  output from the lateral horn regions of the
  spinal cord (sympathetic preganglionic
  efferents) facilitation can occur
• Increased sympathetic stimulation of target
  tissues and organs can result this can be termed
  sympatheticotonia
• Visceral dysfunction can directly follow, or
  happen due to vasomotor effects

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Somato-Visceral reflex
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• The spinal and supraspinal pathways allow a
  rich access of somatic afferents to sympathetic
  neurons. Therefore, when the motion of
  intervertebral joints is even slightly amiss,
  there will be autonomic effects, with resulting
  circulatory, metabolic, and visceral
  repercussions.
• Korr

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• once viscus and soma have become linked in a
  vicious circle, it no longer matters, from a
  therapeutic viewpoint, in which of these the
  vicious circle started. What matters is the
  interruption of the circle.
• Korr

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The Meric clinical approach is based on
segmental arrangement and distribution of nerves
of the autonomic nervous system
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Visceral correlations with VSC

• Colic
• High blood pressure
• Urinary output
• Enuresis
• Gastric acidity and motility
• Pituitary circulation
• Anemia

• Blood sugar levels
• Asthma, allergic rhinitis
• Coronary arteriospasm, dysrhythmias
• Pupillary diameter
• Migraine
• dysmenorrhea

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Alternative hypothesis the simulated visceral
disease model

• Somatic afferents and visceral afferents converge
  on, and may facilitate common neuronal pools,
  leading to the misperception by higher levels of
  the CNS that visceral dysfunction may be
  occurring, when, in fact, the somatic afferent
  signaling is the problem
• So, some apparent remission of visceral symptoms
  after adjustments may have not been visceral in
  origin

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Common sets of indistinguishable perceptive,
somatic, autonomic and neuroendrocrine responses
Primary somatic dysfunction or disease
Somatic afferent signals
Leading to
Equally indistinguishable sets of signs and
symptoms
CNS Afferent Convergence
Visceral afferent signals
Facilitation of common neuronal pool by either
visceral or somatic afferents
Primary visceral dysfunction or disease
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What to Tell Patients (regarding somato-visceral
reflexes)

• Neural effects of subluxation include alteration
  of the blood supply and other controls of body
  organs and systems
• Neural interference from VSC can cause or
  contribute to dysfunction of all body systems-
  chiropractic is not just about back and neck pain

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F. Viscero-Somatic Reflex Hypothesis (aka
viscero-motor) visceral afferents somatic
efferents
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Viscero-Somatic reflex model

• Visceral dysafferentation due to viscus (organ)
  injury/pathology can cause or predispose the
  spine to develop subluxation or somatic
  precursors
• Facilitation of the anterior horn of the cord
  allows visceral input to cause reflexive muscle
  hypertonicity and other somatic effects
• suggests that VSC can be caused by chemical
  stressors and other insults to body organs

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Viscero-Somatic Reflex
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• The same mechanisms are at work when the
  viscera produce the main disturbance of the cord
  and the somatic (musculoskeletal) involvement is
  secondary (as in referred pain).
• Korr

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• Referred pain of visceral and somatic origin,
  and the associated phenomena, are an example of
  dysfunctional segmental coupling.
• Korr

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Possible Clinical Correlations in Viscero-Somatic
Reflexes

• Lung irritation due to inhalation of toxins
  (i.e., smoking, air pollution, etc..) reflexively
  can cause somatic manifestations in the upper
  thoracic and midcervical regions of the spine
• Stomach- mid-thoracic spine
• Colon- lower thoracic upper lumbar spine

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• From baby in the high chair to grandma in the
  rocker, the axial bones are as liable to be
  displaced by noxious substances which enter the
  system in our food and drink or by inhalation as
  they are by direct accident.
• D.D. Palmer

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What to Tell Patients (regarding viscero-somatic
reflexes)

• Toxins and chemical stresses to body organs can
  be a factor in causing subluxations
• This can cause a recurrence or relapse of ones
  subluxation pattern, or make holding
  corrections difficult
• What we eat, drink, and inhale can influence our
  spine and nerve system

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Reflex Models Review

• The implication is that altered neurologic
  activity tends to be a self-sustaining phenomenon
  because of the naturally-circuitous, reflexive
  fashion in which the nervous system works.
• Altered messages may elicit maladaptive
  responses, which in turn reinforce or worsen the
  original message, in a positive feedback fashion.

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• Osteopathic researchers Patterson and Steinmetz
  concluded that in an area of SDF with
  accompanying motion disorder and muscle tension,
  visceral spasm, or other initiating disorder, if
  the initial stimulus is sufficient or lasts long
  enough, there may be segmental facilitation even
  after the instigating stimulus is removed.

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• Some of the current thinking is that the
  resultant postural muscle hypertonicity not only
  creates hypomobility, but that the muscle
  contraction chokes off its own blood supply, and
  ischemic conditions worsen the inflammatory
  state.
• (a vicious circle is established)

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INJURY
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Trauma
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Anterior horn effects
Trauma
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Lateral horn effects
Trauma
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• Referred pain of visceral and somatic origin,
  and the associated phenomena, are an example of
  dysfunctional segmental coupling.
• Korr

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• Somatic and visceral structures that, in the
  course of normal body activity or adaptive
  response patterns, do not have a functional link
  become clinically coupled only because their
  innervating neurons are segmentally related.
• Korr

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Reflex Models Review

• The implication is that altered neurologic
  activity tends to be a self-sustaining phenomenon
  because of the naturally-circuitous, reflexive
  fashion in which the nervous system works.
• Altered messages may elicit maladaptive
  responses, which in turn reinforce or worsen the
  original message, in a positive feedback fashion.

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• Manipulative therapy is effective when it
  establishes coherent patterns of afferent input
  The proper articular, interosseous, muscular,
  fascial, and ligamentous adjustments allow the
  tissues to report in logical proprioceptive
  patterns, thereby improving afferent input, and
  also relieve mechanical irritation or deformation
  of neural structures.
• Korr

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G. Neurodystrophic Hypothesis( Is also being
referred to currently as the Neuroimmune
Hypothesis)
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Neurodystrophic/Neuroimmune Hypothesis

• Neural dysfunction as a result of VSC is
  stressful to the body and lowers tissue
  resistance, modifying specific and nonspecific
  immune responses
• Specific effects of VSC are not well researched,
  but may include alteration of the trophic
  function of nerves
• Most-accepted current concept is modification of
  sympathetic nerve activity locally and globally
  (i.e..sympatheticotonia)

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• it appears that the SNS significantly
  influences the response, including resistance of
  tissues, to antigenic, infectious, irritative,
  toxic, and even carcinogenic agents. Processes
  such as allergic manifestations, anaphylaxis, and
  immune reactionsalso seem to be under some
  sympathetic influence.
• Korr

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• the SNS regulates all aspects of immune
  function in vivo, including proliferation,
  cytokine production, antibody production, and
  lymphocyte migration.
• Madden, K., Chapter 5, Catecholamines,
  Sympathetic Nerves, and Immunity, in
  Psychoneuroimmunology, Ader, Felton and Cohen,
  2001, p. 198

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Handout

• Elenkov et al The Sympathetic Nerve An
  Integrative Interface between two Supersystems
  The Brain and Immune System, Pharmacol Rev, Vol
  52, 4, 595-638, Dec. 2000
• Dr. Dan Murphys best article of all time

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• Subluxation reduces brain/cortical summation.
• Murphy

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• Reduced brain summation dis-inhibits the
  sympathetic nervous system.
• Murphy

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• Correcting the subluxation will reduce SNS
  activity, reduce catecholamine release, enhance
  the Th1 response which will improve infection
  fighting and inhibit the Th2 response, which
  will reduce allergy/atopic disease signs and
  symptoms.
• Murphy

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• the most critical effect of manipulative
  therapy is the quieting of sympathetic
  hyperactivity.
• Korr

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Adjustments Anti-inflammatory?

• Recent research suggests an effect of one type of
  adjustment (HVLA with cavitation) may be to help
  control the systemic inflammatory response
• Study showed this type of adjustment was
  associated with a short-term decreases in
  production of TNF-a (Tumor Necrosis Factor a)
• Subluxation may result in sustained increased
  production of TNF-a, which is not the normal
  function of this cytokine (usually short-term)

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Adjusting and TNF-a

• Spinal manipulative therapy can exert a
  modulatory and/or stabilizing effect on the
  inflammatory response in vivo.
• Teodorczyk-Injeyan et al, Attenuation of Tumor
  Necrosis Factor Secretion following Spinal
  Manipulative Therapy in Normal Subjects J of
  Chiro Ed 18(1), Spring 2004

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Conclusion

• Subluxation can disrupt the bodys ability to
  keep this part of the inflammatory response
  short-term
• Ordinarily, balance between sympathetic and
  parasympathetic portions of the autonomic nervous
  system keeps this in check
• Subluxation leads to dysautonomia (Kent)

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Recall Kents 3-D Model of VSC?

• 1. Dyskinesia
• (somatic dysafferentation)
• 2. Dysponesis
• (dysafferentation leads to dysefferentation
  i.e. aberrant adaptive responses)
• 3. Dysautonomia
• functional autonomic dystonia

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Further Conclusions

• Correction of subluxations
• 1. improves spinal motion
• 2. improves spinal alignment
• 3. leads to improvement in somatic
  afferentation, which
• 4. enhances immune response by balancing the
  sympathetic and parasympathetic divisions of the
  autonomic nervous system

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• Amazingly, Palmers concept of altered tone
  of the nervous system being the cause of disease
  then has some support in the current
  neurophysiologic literature regarding
  facilitation and sympatheticotonia.
  (dysautonomia)
• Leach, 94, p. 114