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Models of Vertebral SubluxationModels of Vertebral Subluxation

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Background ReadingBackground Reading

• Fundamentals of Chiropractic– pp. 129-153

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Subluxation, Lay DefinitionSubluxation, Lay Definition

• A subluxation is loss of proper position or motion of a vertebral segment which may impact proper nervous system function. (Lay definition)

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Subluxation, Subluxation, NINCDS DefinitionNINCDS Definition

• A subluxation is the alteration of the normal dynamics, anatomical or physiological relationships of contiguous articular structures. (National Institutes of Neurological and Communicative Disorders and Strokes

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Subluxation, ACC Definition Subluxation, ACC Definition

• A subluxation is a complex of functional, structural, and/or pathological articular changes that compromise neural integrity and may influence organ system function and general health.

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ACC on Subluxation (2)ACC on Subluxation (2)

• A subluxation is evaluated, diagnosed and managed through the use of chiropractic procedures based on the best available rational and empirical evidence.

• The preservation and restoration of health is enhanced through the correction of subluxation.

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Vertebral Subluxation ComplexVertebral Subluxation Complex(Faye, 1989)(Faye, 1989)

• Subluxation is a complex clinical entity comprising one or more of the following:

1. Neuropathophysiology (nerve)

2. Kinesiopathology (movement)

3. Myopathology (muscle)

4. Histopathology (cellular changes)

5. Biochemical

SubluxationPathophysiologyPathology

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Key Points in Faye’sKey Points in Faye’sPerspective on SubluxationPerspective on Subluxation

• Primary emphasis on dynamic vertebral joint motion, not “bone out of place.”

• Directions of vertebral motion– rotation about the longitudinal axis

– right or left lateral flexion

– anterior flexion

– posterior extension

– long-axis distention

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FixationFixation

• Loss of segmental mobility within its normal physiologic ROM

• Ankylosis = 100% fixation

• Most fixations in 20-80% range

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Hypomobility Hypomobility and Hypermobiltyand Hypermobilty

• Fixations are HYPOmobile

• HYPERmobility denotes excessive joint movement– Joint is too loose– Ligaments are lax, stretched too far– DO NOT ADJUST hypermobile joints

• Will render them even more hypermobile ***

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NEUROPATHOPHYSIOLOGYNEUROPATHOPHYSIOLOGY

SUSTAINED HYPERACTIVITY Posterior Horn Sensory Manifestations

Irritation Facilitation Lateral Horn Sympathetic Vasomotor

Anterior Horn Muscle Hypertonicity

NERVE COMPRESSION

Atrophy Pressure Degeneration Sympathetic Atonia

Anesthesia

DECREASED AXOPLASMIC FLOW

Compression or Irritation Axoplasmic Transport Adverse trophic influences Mechanism on development, growth

and maintenance of end organs

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KinesiopathologyKinesiopathology

• Hypomobility• Hypermobility• Diminished or absent joint play• Change of axis of movement• Theorized to affect nociceptors,

mechanoreceptors• When chronic fixation present, ligaments

shorten

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MyopathologyMyopathology

• Causes of spasm, hypertonicity (increased muscle tension)– Compensation– Facilitation– Hilton’s Law

• “Nerve supplying a joint also supplies muscles that move joint and skin covering articular insertion of those muscles”

– Visceromotor reflex

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Myopathology (2)Myopathology (2)

• Myopathologic component of subluxation complex can also take the form of atony (muscles too loose, lax, weak)

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HistopathologyHistopathology

• Inflammation– Pain– Heat– Swelling

• Possible causes– Trauma– Hypermobile irritation– Part of repair process

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Biochemical ComponentBiochemical Component

• Hormonal and chemical effects or imbalance related to the pre-inflammatory stress syndrome, and the production of histamine, prostaglandin, and bradykinin

• Result of trauma or fixation of the spinal articulation is proposed to affect nociceptive impulses resulting in aberrant somatic afferent input into the segmental spinal cord.

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Lantz 9-Component ModelLantz 9-Component Model

• Reformulates Faye model to add vascular, connective tissue, inflammatory response, physiologic and anatomic categories

• Overlap significant between 2 models

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Vascular ComponentVascular Component

• Segmental artery passing through IV canal into spinal canal supplies each segment.

• Branches supply dorsal and ventral nerve roots

• Segmental veins drain spinal canal and vertebral column

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Vascular Component (2)Vascular Component (2)

• Blood vessels subject to same mechanical pressures as nerve roots– May be compressed

• Lantz proposes immobilization may lead to localized venous stasis, and…

• Lack of proper venous drainage may lead to inflammation

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Connective Tissue ComponentConnective Tissue Component

• CT components– Bone– IVD– Articular cartilage– Interspinous ligaments– Other support structures

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Connective Tissue Component Connective Tissue Component (2)(2)

• With CT immobilization (as in fixation) – Synovial fluid undergoes fibrofatty consolidation,

progressing to more adherent fibrous tissue and matrix development for the deposition of bone salts in the final stages of ankylosis.

– In the immobilized joint, articular cartilage shrinks due to loss of proteoglycans. This shrinkage leads to softening of cartilage, thus rendering the articulation more susceptible to damage by minor trauma.

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AdhesionsAdhesions

– In the immobilized joint, adhesions form between adjacent connective tissue structures.

• Examples: between the nerve root sleeve and adjacent capsular and osseous structures in the IVF, between tendons and articular capsules.

• Forced motion creates a physical disruption of the adhesions breaking intermolecular cross-linkages.

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Inflammatory ComponentInflammatory Component

• Faye model grouped this under Vascular component

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Results of Joint FixationResults of Joint Fixation

• Degenerative changes• Pain• Excitation of alpha-motoneurons » myospasm• Excitation of preganglionic SNS neurons»

vasoconstriction, nociceptive reflexes• Deafferentation of propriospinal tract, DCs,

spinocerebellar tracts