Toward Theory Driven Chiropractic: The Science of Subluxation Robert A. Leach, DC, MS, FICC, CHES • Author, The Chiropractic Theories • Certified Health Education Specialist • Private Practice since 1979, Starkville, Mississippi Copyright 2020 by Robert A. Leach Further Reading… The textbook for this program is available through the Parker Chiropractic College bookstore, via Amazon, or your local bookseller. 2/5/2020 I. Subluxation: Philosophy/Dogma vs Philosophy/Theory Driven Will we adopt a questioning philosophy, informed by evidence, that drives our practices? 2/5/2020 Do you ever stop to ponder professional and clinical questions? ●Is there scientific evidence for subluxation, or should we abandon the term? ●Does theory (aka “the story”) matter? ●Which is more important: research of theory or outcomes? How to know what works? How do you know if one technique is better or works better than another? Would you buy a used car without a test drive? Would you feel better about paying more if you could drive it to your mechanic to check it out? Do you read about computers or cars and crash and mileage tests before you buy? Why should the public buy chiropractic that is untested? Why should a chiropractor buy a technique or a subluxation detection system that is untested? These and similar questions should arouse the chiropractor toward a lifetime of learning that will benefit her or his patients and practice. Best of Times: Theory Informs Practice, Improves Outcomes Iridology Misalignment Myelopathy Reflexology II. Disproven and Short leg deficiency Untested “Silent” vertebral subluxation Chiropractic complex Theories Surrogate testing Technique system processes and testing III. Promising Evidence Informed Spinal Manipulation Theories Today The First Subluxation Hypothesis: Fixation •A simple subluxated vertebra differs from a normal vertebra only in its field of motion and the center of its field of motion; because of its being subluxated, its various positions of rest are differently located than when it was a normal vertebra . its field of motion may be too great in some directions and too small in others. (Smith, Langworthy, Paxson, Modernized Chiropractic, 1906). NINDS Description: Search Key Words/ #Pubmed hits: Fixation h. spinal dysfunction, 367; spine manipulation stiffness, 124; manipulable spinal lesion, 11; 1975 NINDS chiropractic spine compliance,29 Conference Immob. Deg. h. inflammation spine pain, 1,454; immobilization Hypotheses degeneration, 342 Seeing promising Neurodystrophy h. psychoneuroimmunology 2,571; inflammation spine pain, 1,454 ; subsequent study: neurodystrophy,27 Subluxation h. forward head posture, 792; spinal dysfunction, 367; chiropractic subluxation, 218 Somatoautonomic Reflex h. autonomic nervous system spinal manipulation, 96; neuroplasticity spinal manipulation, 47; visceral responses to spinal manipulation, 10 Axoplasmic aberration Neuroplasticity Additional Facilitation BioPsychoSocial Hypotheses Forward head Segmental dysfunction tilt/postural Vertebrobasilar Relating to Immobilization insufficiency degeneration Wellness Modern Inflammation Chiropractic Instability Minimum energy Theory: Mimicry Inflammation affecting Zygapophyseal Joints Patterson-Steinmetz Model •Spinal Learning is the facilitation hypothesis based on the following facts: A) a small lesion in the cerebellum of an anesthetized animal causes the limbs on one side to actively flex and remain in that position (top). B) Immediate severance of spinal cord at T7 results in paralysis of the hind limb (middle). C) If the hind limb flexion is allowed to remain for even 45 minutes, it becomes “learned” by the spine and remains despite section of the cord (bottom). Contemporary summary of afferent pool for the alpha motor neuron, showing significant contributions from spinal interneuron pool whose inputs include projections received from corticospinal tract. Front Hum Neurosci. 2013:7:85. Neuroimmune Hypothesis Begins in 1950s with Hans Selye, M.D., Ph.D.’s Hypothesis: Localized Adaptation to Stress Questions: •Could Selye’s observations apply to spinal lesions? •Could inflammation trigger fixation, facilitation, and have somatoautonomic and somatovisceral effects? ATTENUATION EFFECT OF SPINAL MANIPULATION ON NEUROPATHIC AND POSTOPERATIVE PAIN THROUGH ACTIVATING ENDOGENOUS ANTIINFLAMMATORY CYTOKINE INTERLEUKIN 10 IN RAT SPINAL CORD • This animal-based study showed that spinal manipulation reduced neuropathic pain due to intervertebral foramen compression. • Spinal manipulation reduced postoperative pain after relief of nerve compression. • Spinal manipulation reduced neural inflammation and nociceptive neural hyperexcitability. • Spinal manipulation increased endogenous anti-inflammatory cytokine IL-10 in the spinal cord. -J Manipulative Physiol Ther 2016;39:42-53 Good vs Bad Stress and Brain Aging Figure 4. Adaptation of McEwen model of good versus bad stress, showing dose response of increasing amounts and frequency of adrenal steroids in response to acute stressors having initially beneficial effects such as facilitation of long-term potentiation and memory. Cell. 2014 Nov 6;159(4):727-37. doi: 10.1016/j.cell.2014.10.035. Neuronal plasticity: beyond the critical period. Hübener M1, Bonhoeffer T2. Neuronal plasticity in the brain is greatly enhanced during critical periods early in life and was long thought to be rather limited thereafter. Studies in primary sensory areas of the neocortex have revealed a substantial degree of plasticity in the mature brain, too. Often, plasticity in the adult neocortex lies dormant but can be reactivated by modifications of sensory input or sensory-motor interactions, which alter the level and pattern of activity in cortical circuits. Such interventions, potentially in combination with drugs targeting molecular brakes on plasticity present in the adult brain, might help recovery of function in the injured or diseased brain. Reorganization in Secondary Somatosensory Cortex in Chronic Low Back Pain Patients Results. Nonpainful PA pressure revealed no cortical reorganization in S1. In contrast, the extent of S2 activation in the CLBP group was significantly reduced in both hemispheres. In the control group, a somatotopy was identified for the lumbar vertebrae between L1 and L3, respectively, and L5 in S2 of the right hemisphere. Most importantly, a blurring of the somatotopic representation of the lumbar spine in S2 was observed in the patient group. Conclusion. Together, these maladaptive changes suggest a reorganization of higher-order processing for sensory information in CLBP patients that might have implications for a decreased sensory acuity, also related to body perception and subsequent altered functioning of the lumbar spine. -SPINE Volume 41, Number 11, pp E667–E673, 2016 Somatosensory evoked potentials show plastic changes following a novel motor training task with the thumb D. Andrew a, H. Haavik b, E. Dancey a, P. Yielder a, B. Murphy a,⇑ a University of Ontario Institute of Technology, Faculty of Health Sciences, 2000 Simcoe Street North, Oshawa, Ont. L1H 7K4, Canada bNew Zealand College of Chiropractic, Centre for Chiropractic Research, 6 Harrison Road Mt Wellington, P.O. Box 112-044 Newmarket, Auckland 1149, New Zealand Objective: Accumulating evidence indicates that plastic changes can be maladaptive in nature, resulting in movement and neurological disorders. The aim of this study was to further the understanding of these neurophysiological changes in sensorimotor integration (SMI) using somatosensory evoked potentials (SEPs) and concurrent performance changes following a repetitive typing task. Effects of 12 Weeks of Chiropractic Care on Central Integration of Dual Somatosensory Input in Chronic Pain Patients: A Preliminary Study The observations in 6 subjects revealed that 12 weeks of chiropractic care improved suppression of SEPs evoked by dual upper limb nerve stimulation at the level of the motor cortex, premotor areas, and/or subcortical areas such as basal ganglia and/or thalamus. It is possible that these findings explain one of the mechanisms by which chiropractic care improves function and reduces pain for chronic pain patients. -J Manipulative Physiol Ther 2017;40:127-138 Manipulation of Dysfunctional Spinal Joints Affects Sensorimotor Integration in the Prefrontal Cortex: A Brain Source Localization Study Results: SM decreased the N30 amplitude by 16.9 ± 31.3% (푃 = 0.02), while no differences were seen following the control intervention (푃 = 0.4). Brain sourcemodeling revealed a 4-source model but only the prefrontal source showed reduced activity by 20.2±12.2% (푃 = 0.03) following SM. Conclusion. A single session of spinal manipulation of dysfunctional segments in subclinical pain patients alters somatosensory processing at the cortical level, particularly within the prefrontal cortex. - Neural Plasticity 2016 Impact of Spinal Manipulation on Cortical Drive to Upper and Lower Limb Muscles Heidi Haavik 1,*, Imran Khan Niazi 1,2, Mads Jochumsen 2, Diane Sherwin 3, Stanley Flavel 1 and Kemal S. Türker 4 Spinal manipulation resulted in a 54.5% +/- 93.1% increase in maximum motor evoked potential (MEPmax) for APB and a 44.6% +/- 69.6% increase in MEPmax for TA. For the MRCP data following spinal manipulation there were significant difference for amplitude of early bereitschafts-potential (EBP), late bereitschafts potential (LBP) and also for peak negativity (PN). The results of this study show that spinal manipulation leads to changes in cortical excitability, as measured