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Embryology and developmental pathology

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Embryology and developmental pathology of the spinal column

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Embryology and developmental pathology

  1. 1. Spinal Embryology and Developmental Pathology Richard C Rooney, MD, FACS rrooney@seattlespinegroup.com
  2. 2. Stages of Neural-Spinal Development- First Week Moore, K. The Developing Human
  3. 3. Stages of Neural-Spinal Development- Second Week Moore, K. The Developing Human
  4. 4. Stages of Neural-Spinal Development- Third Week • Primitive Streak Moore, K. The Developing Human
  5. 5. Stages of Neural-Spinal Development- Third Week • Primitive Streak Moore, K. The Developing Human
  6. 6. Stages of Neural-Spinal Development- Third Week • Notochord Moore, K. The Developing Human
  7. 7. Stages of Neural-Spinal Development- Third Week • Notochord
  8. 8. Stages of Neural-Spinal Development- Third Week • Notochord
  9. 9. Stages of Neural-Spinal Development- Third Week • Notochord
  10. 10. Stages of Neural-Spinal Development- Third Week • Notochord
  11. 11. Stages of Neural-Spinal Development- Third Week • Notochord
  12. 12. Stages of Neural-Spinal Development- Third Week • Notochord Moore, K. The Developing Human
  13. 13. Stages of Neural-Spinal Development- Third Week • Mesoderm- Day 16
  14. 14. Stages of Neural-Spinal Development- Third Week • Somites Moore, K. The Developing Human
  15. 15. Stages of Neural-Spinal Development- Third Week • Mesoderm
  16. 16. Stages of Neural-Spinal Development- Third Week • Neural Plate Moore, K. The Developing Human
  17. 17. Stages of Neural-Spinal Development- Fourth Week • Neural Plate – Neuralization- closure of the neural groove to form the neural tube Moore, K. The Developing Human
  18. 18. Stages of Neural-Spinal Development- Fourth Week • Somites- 42 pairs • Neural Plate and cranial-most 4 somites form the brain Moore, K. The Developing Human
  19. 19. Stages of Neural-Spinal Development- Fourth Week • Somites- divide into dense and sparse areas Moore, K. The Developing Human
  20. 20. Stages of Neural-Spinal Development- Fourth Week • Centrum- dense portion of cephalad with sparse portion of caudal somite Moore, K. The Developing Human
  21. 21. Primodial Vertebral Segment Bullough, Atlas of Spinal Diseases
  22. 22. Vertebral Development Bullough, Atlas of Spinal Diseases
  23. 23. Vertebral Development Bullough, Atlas of Spinal Diseases
  24. 24. Stages of Neural-Spinal Development- Fifth Week • Neural Plate- Thinning of 4th ventricle for Foramen of Magendie • Notochord- Degeneration in Vertebral Body area Moore, K. The Developing Human
  25. 25. Stages of Neural-Spinal Development- Fifth Week • Vertebrae- Mesenchymal model finished Moore, K. The Developing Human
  26. 26. Stages of Neural-Spinal Development- Sixth Week • Vertebrae- – Chondrification- 6th week – Ossification Centers- 7th week Moore, K. The Developing Human
  27. 27. Further Vertebral Development • Neural Central Joint- fuses 3rd to 6th year • Vertebral Arch- fuses 3rd to 5th year Moore, K. The Developing Human
  28. 28. Further Vertebral Development • Rib, Body and Vertebral Arch equivalents Grey’s Anatomy
  29. 29. A Clarification of Terms • Physeal Plate- Cartilage plate where growth occurs. • Epiphysis- Area of bone on the end of the physeal plate that contributes to longitudinal growth of a long bone • Apophysis- An area of bone adjacent to a physeal plate that does not contribute to longitudinal growth (Secondary Centers of Ossification)
  30. 30. A Clarification of Terms • Apophysis- An area of bone adjacent to a physeal plate that does not contribute to longitudinal growth (Secondary Centers of Ossification) Moore, K. The Developing Human
  31. 31. Recap Spinal Cord Development Moore, K. The Developing Human
  32. 32. Recap Spinal Cord Development • Neural tube-- CNS • Neural Crests-- PNS and ANS • Neural Canal– Ventricles and central canal Moore, K. The Developing Human
  33. 33. Vertebral Column Development Moore, K. The Developing Human
  34. 34. Where Things Go Wrong • Failure of Canal to Close Moore, K. The Developing Human
  35. 35. Where Things Go Wrong • Failure of Canal to Close Moore, K. The Developing Human
  36. 36. Where Things Go Wrong CSF Flow/ Drainage Problems Chiari malformations- (aka Arnold-Chiari) definition- downward compression (not traction) of the lower cerebellar contents into the cervical region Typed by amount of displacement- -correlates with age of onset -correlates with severity of symptoms Shrek, H. The Cervical Spine
  37. 37. Where Things Go Wrong CSF Flow/ Drainage Problems Chiari malformations- Type I - mildest - originally called adult onset - caudal displacement of cerebellar tonsils (with dentate ligaments, 4th ventricle, cervical roots and brain stem in normal position.) Shrek, H. The Cervical Spine
  38. 38. Where Things Go Wrong CSF Flow/ Drainage Problems Chiari malformations- Type II - more severe - originally called congenital - caudal displacement of cerebellar vermis, 4th ventricle, medulla and lower pons Shrek, H. The Cervical Spine
  39. 39. Where Things Go Wrong CSF Flow/ Drainage Problems Chiari malformations- Type III - most severe - caudal displacement of cerebellum and brain stem into high cervical meningiocele Shrek, H. The Cervical Spine
  40. 40. Chiari Malformations con’t. • Symptoms- due to neural compression at foramen magnum – Lower cranial nerve dysfunction – Long tract signs • Associated with: – Scarring – Compressive atrophy – Fibrous band Shrek, H. The Cervical Spine
  41. 41. Chiari Malformations con’t. • Bony deformity = Basilar Impression – May be secondary to other conditions – MCC- congenital anomaly in cerv-occ. Area – Def.- upward movement of base of skull in the foramen magnum area – Measured by intracranial extension of the tip of odontoid Shrek, H. The Cervical Spine
  42. 42. Basilar Impression- measurement • Chamberlain’s Line (Red) – Hard palate to foramen magnum – Odontoid below line +/- 4 mm. Shrek, H. The Cervical Spine
  43. 43. Basilar Impression- measurement • McRae’s Line (Green) – AP of foramen magnum- odontoid below this line – Symptoms when AP diameter <20 mm. Shrek, H. The Cervical Spine
  44. 44. Basilar Impression- measurement • Wackenheimer’s Line (Blue) – Drawn along clivus – Odontoid is ventral Shrek, H. The Cervical Spine
  45. 45. Fixation +/- Position Changes • Tethered Cord – Cause unknown, probably multiple – Assoc. with cutaneous lesion 54% – Assoc. with lipoma 15% – Female 2:1 – Slowly progressive motor dysfunction – Recovery after surgery- poor- operate early! Weinstein, S. The Pediatric Spine
  46. 46. Fixation +/- Position Changes • Diastematomyelia – Cord divided by fibrous, cartilagenous or bony septum – Cutaneous lesion +/- – Dural tube- one or two – Diagnose before spinal instrumentation! Weinstein, S. The Pediatric Spine
  47. 47. Multisystem Problems • VATER/VACTERL – V- vertebral anomalies/ dysgenesis, vascular – A- anal atresia – C- cardiac anomalies – T- tracheo-eophageal (T-E) fistulas – E- esophageal atresia – R- renal anomalies – L- limb anomalies, radial (forearm) dysplasia – S- single umbilical artery Weinstein, S. The Pediatric Spine
  48. 48. Segmentation Problems • Hemivertebra- Segmented vs. non-segmented (scoliosis lecture) Weinstein, S. The Pediatric Spine
  49. 49. Segmentation Problems • Failure of Segmentation (aka congenital fusions) – Klippel-Feil Syndrome • Short neck • Low posterior hair line • Limited cervical ROM • Beware of compensatory hyper-mobility • Familial component • Assoc. with Fetal Alcohol Syndrome Weinstein, S. The Pediatric Spine
  50. 50. Questions? • Fellowship Trained • Board Certified • Experienced • Diligent about the literature • Second opinion • rrooney@seattlespinegroup.com Confidential

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