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Information

Differential Diagnosis of Skull and Spine Disorders

= abnormal / incomplete fusion of midline embryologic mesenchymal, neurologic, bony structures

External signs (in 50%):

  • subcutaneous lipoma
  • hypertrichosis
  • pigmented nevi
  • pathologic plantar response
  • bladder + bowel dysfunction
  • spastic gait disturbance
  • foot deformities
  • absent tendon reflexes
  • sinus tract
  • skin dimple

Spina Bifida!!navigator!!

= incomplete closure of bony elements of the spine (lamina + spinous processes) posteriorly

Spina Bifida Occulta

= OCCULT SPINAL DYSRAPHISM

= cleft / tethered cord WITH skin cover

Frequency: 15% of spinal dysraphism

  • rarely leads to neurologic deficit in itself
    Associated with:
    1. vertebral defect (85 – 90%)
    2. lumbosacral dermal lesion (80%):
      • hairy tuft (= hypertrichosis), dimple, sinus tract, nevus, hyperpigmentation, hemangioma, subcutaneous mass
        1. Diastematomyelia
        2. Lipomeningocele
        3. Tethered cord syndrome
        4. Filum terminale lipoma
        5. Intraspinal dermoid
        6. Epidermoid cyst
        7. Myelocystocele
        8. Split notochord syndrome
        9. Meningocele
        10. Dorsal dermal sinus
        11. Tight filum terminale syndrome

Spina Bifida Aperta

= SPINA BIFIDA CYSTICA

= posterior protrusion of all / parts of the contents of the spinal canal through a bony spinal defect

Frequency: 85% of spinal dysraphism

Associated with: hydrocephalus, Arnold-Chiari II malformation

  • Most severe form of midline fusion defect
  • neural placode WITHOUT skin cover
    Associated with: neurologic deficit in >90%
  1. Simple meningocele
    = herniation of CSF-filled sac without neural elements
  2. Myelocele
    = midline plaque of neural tissue lying exposed at the skin surface
  3. Myelomeningocele
    = a myelocele elevated above skin surface by expansion of subarachnoid space ventral to neural plaque
  4. Myeloschisis
    = surface presentation of neural elements completely uncovered by meninges

Caudal Spinal Anomalies

= malformation of distal spine and cord

Associated with: hindgut, renal, genitourinary anomalies

  1. Terminal myelocystocele
  2. Lateral meningocele
  3. Caudal regression

Segmentation Anomalies of Vertebral Bodies!!navigator!!

during 9th–12th week of gestation two ossification centers form for the ventral + dorsal half of vertebral body

  1. Asomia = agenesis of vertebral body
    • complete absence of vertebral body
    • hypoplastic posterior elements may be present
  2. Hemivertebra
    1. Unilateral wedge vertebra
      • right / left hemivertebra
      • scoliosis at birth
    2. Dorsal hemivertebra
      • rapidly progressive kyphoscoliosis
    3. Ventral hemivertebra (extremely rare)
  3. Coronal cleft
    = failure of fusion of anterior + posterior ossification centers
    May be associated with: premature male infant, Chondrodystrophia calcificans congenita
    Location: usually in lower thoracic + lumbar spine
    • vertical radiolucent band just behind midportion of vertebral body; disappears mostly by 6 months of life
  4. Butterfly vertebra
    = failure of fusion of lateral halves ← persistence of notochordal tissue
    May be associated with: anterior spina bifida ± anterior meningocele
    • widened vertebral body with butterfly configuration (AP view)
    • adaptation of vertebral endplates of adjacent vertebral bodies
  5. Block vertebra

    = congenital vertebral fusion
    Location: lumbar / cervical
    • height of fused vertebral bodies equals the sum of heights of involved bodies + intervertebral disk
    • “waist” at level of intervertebral disk space
  6. Hypoplastic vertebra
  7. Klippel-Feil syndrome

Outline