Spinal Stability

1. Spinal Stability Tara Jo Manal PT, SCS, OCS

2. Clinical Instability • Loss of the ability of the spine under physiologic loads to maintain its pattern of displacement so that there is no initial or additional neurological deficit, no major deformity, and no incapacitating pain • White and Panjabi

3. Clinical Instability • Anatomic Considerations • Biomechanical Factors • Clinical Considerations • Treatment Considerations • Recommended Evaluation system • Recommenced management • Recorded cases of patient post-polio with cervical paralysis and no instability if bones and ligaments remain intact

4. Biomechanics of Spinal Cord and Nerve Roots • Cord does not slide up and down (v.small) • Accordion like- lengthen on one side and shorten on the other (ie sidebending) • Greatest stretching occurs between C2 and T1 (<20%) • Injury is due to loss of cord elasticity, displacement or space occupying lesions • High compliance in the axial plane, less in the horizontal plane

5. Types of Instability • Kinematic • Motion increased • Instantaneous axes of rotation altered • Coupling characteristics changed • Paradoxical motion present • Component Instability • Trauma • Tumor • Surgery • Degenerative changes • Developmental chages

6. C0-C1 • Unstable in childhood • Dislocations are generally fatal • Instability identified by x-ray • Rotation >8° is pathological • Translation > 1 mm

7. C1-C2 • Instability due to dens fracture • Vertebral translation or Rotation • Bone spur • Little contribution of the facet/capsule compared to dens and ligamentous ring • Alar ligament test • C1-C2 > 56° is abnormal

8. Jefferson Fracture C1 Ring Distruption, overhang of lateral masses of C2

9. C2-T1 • Failure consists of injury to posterior and anterior elements • Unilateral facet • Root symptoms • Bilateral facet • Spinal medullary injury • Burst Fracture • Horizontal displacement • Spinal cord injury

10. Recognizing Instability • History of a flexion injury • Widening of interspinous space • Subluxation of a facet joint • Compression fracture of adjacent vertebrae • Loss of normal cervical lordosis

11. T1-T10 Overall greater stiffness Spinal cord damage with injury ~10% T11-L1 Spinal cord damage with injury ~4% Thoracic Instability

12. Lumbar Instability • L1-S1 • 3% Fracture and dislocation have neurological signs • Disconnect between displacement and neurological signs • >4.5mm or 15% • Facet has a crucial role in stability (rot and SB)

13. Stabilization of the Spine • Passive system • Active system • Neural control

14. Muscular Control of the Spine • Rotatores and Intertransversarii • Function primarily as force transducers • Position Sensors • Electrically silent with large rotations (involving Abs)

15. Muscular Control of the Spine • Extensors – Longissimus, Iliocostalis • Thoracic area ~75% slow twitch fibers • Lumbar area ~50% mix • Lumbar area- in flexion provide a compressive force in the lumbar to limit shear

16. Muscular Control of the Spine • Extensors – Multifidi • Span only a few joints • Produce extensor torque/resistance • Only small amounts of rotation or SB • Contribute to correction or support

17. Muscular Control of the Spine • Abdominal Muscles • Rectus • Major trunk flexor • Active with sit-up and curl-ups • Little to no evidence to support upper/lower differentiation

18. Muscular Control of the Spine • Abdominal Wall- Ext/Int Oblique • Torso Rotation and Lateral flexion

19. Muscular Control of the Spine • Abdominal Wall-Transverse abdominis • Beltlike support and generation of intra-abdominal pressure • Delayed onset during ballistic movements in patient’s with LBP

20. Muscular Control of the Spine • Psoas • Primarily hip flexor • Compressive force to spine during contraction • Questionable contribution to spine stability • If so, under high hip flexor forces

21. Muscular Control of the Spine • Quadratus Lumborum • Highly involved with spine stabilization • Active in flexion, extension and SB • During Lifting, increased oblique activity followed increases in QL

22. Muscular Control of the Spine • Deep Rotators- position sensors • Extensor Group • Generate large extensor moments • Generate posterior shear • Affect one or two segments

23. Co-activation of the Muscular Spine • 90N force (20lbs) creates buckling without muscular forces • Co-contraction increases support against buckling

24. Muscular Stability • Continuous contraction • ~10% MVIC of abdominals • No single muscle is critical one

25. Joint Shear Testing

26. Generalized Ligamentous Laxity • Elbow Hyperextension >10° • Passive Hyperextension of 5th finger >90° • Abduction of thumb to forearm • Knee Hyperextension >10° • Forward flexion hands to floor (knees ext) • Tested Billateral: Total score: /9

27. Neutral Spine

28. Abdominal Bracing

29. Curl-up Beginner • Maintain lordosis with hands • Attempt to lift head (little to no motion) • Raise head and shoulders (no cervical flexion) • One leg flexed one extended

30. Curl-up Intermediate • Elbows off the table

31. Curl-up Advanced • Fingers on forehead

32. Side Bridge Remedial

33. Side Bridge Reverse • Lift legs off the bed

34. Side Bridge Knees Flexed • Knees flexed

35. Side Bridge Intermediate • Legs extended

36. Side Bridge Intermediate Variation • Legs extended • Rolling of torso on legs

37. Side Bridge Advanced

38. Birddog, Remedial • Hands and knees, raise one hand off bed • Progress to hand and opposite knee

39. Birddog, Beginner’s • Raise one arm or leg at a time

40. Birddog, Intermediate • Raise one arm and leg at a time • Hold 6-8 seconds

41. Birddog, Advanced • Raise one arm or leg at a time • Avoid Returning to the bed, sweep and resume

42. Isometric Rotation • Isometric Activity