1 Models of Vertebral Subluxation

2 Background Reading Fundamentals of Chiropractic –pp

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

4 Subluxation, NINCDS 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

5 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.

6 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.

7 Vertebral Subluxation Complex (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 Subluxation  Pathophysiology  Pathology

8 Key Points in Faye’s Perspective 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

9 Fixation Loss of segmental mobility within its normal physiologic ROM Ankylosis = 100% fixation Most fixations in 20-80% range

10 Hypomobility and 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 ***

11 NEUROPATHOPHYSIOLOGY 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 Mechanismon development, growth and maintenance of end organs

12 Kinesiopathology Hypomobility Hypermobility Diminished or absent joint play Change of axis of movement Theorized to affect nociceptors, mechanoreceptors When chronic fixation present, ligaments shorten

13 Myopathology 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

14 Myopathology (2) Myopathologic component of subluxation complex can also take the form of atony (muscles too loose, lax, weak)

15 Histopathology Inflammation –Pain –Heat –Swelling Possible causes –Trauma –Hypermobile irritation –Part of repair process

16 Biochemical 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.

17 Lantz 9-Component Model Reformulates Faye model to add vascular, connective tissue, inflammatory response, physiologic and anatomic categories Overlap significant between 2 models

18 Vascular 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

19 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

20 Connective Tissue Component CT components –Bone –IVD –Articular cartilage –Interspinous ligaments –Other support structures

21 Connective Tissue Component (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.

22 Adhesions –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.

23 Inflammatory Component Faye model grouped this under Vascular component

24 Results 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