1. Disorders of Neural Tube Closure

2. Review of Neuroembryology
Dorsal induction
Primary neurolation: 3-4 wks gestation Brain and upper spine
Secondary neurolation: 4-5 wks gestation Distal spine

3. Neural groove

4. Neural tube

5. Disorders of neural tube closure
Chiari I-IV
Encephaloceles
Anencephaly
Corpus Callosum Agenesis
Spinal Dysraphism (Spina bifida)
- Menigoceles
- Myelomeningoceles
Tethered chord

6. Chiari I
ANATOMY
Peglike cerebellar tonsils displaced into upper cervical canal ( >10mm)
HCP 25%
Syringomyelia 60%
Skeletal anomalies 25%

7. Chiari I: displaced tonsils

8. Chiari I: syringomyelia

9. Chiari I: syringomyelia

10. Chiari I Clinical Asympotmatic (30%) Headache Weakness
Cerebellar signs
Herniation >12mm invariably symptomatic

11. Chiari I Treatment Observation if asymptomatic
Surgery if symptomatic: p-fossa decompression +- cervical laminectomy

12. Chiari II Anatomy Calvarial defects Small p-fossa Fenestrated falx
HCP in 90%
Myelomeningocele in 100%
Syringohydromyelia in 50%-90%

13. Chiari II: Brain MRI

14. Chiari II: Calvarial defects , falx

15. Chiari II Clinical Dysphagia Apneic spells Stridor Aspiration
Arm weakness

16. Chiari II
Treatment
Shunt
P-fossa decompression
Repair of MM

17. Chiari III and IV Chiari III
Most severe form. Chiari II + low occiptial or high cervical encephalocele. Usually incompatible with life
Chiar IV
Severe cerebellar hypoplasia or absence. No herniation
Extremely rare

18. Enephaloceles Anatomy
Failure of the anterior neural tube to close due to genetic, infection, or toxic reasons.
1/1000
Distorted parts of the (covered) brain protruding extracalvarially

19. Encephalocele Anatomy Occipital 90% Parietal 10% Transsphenoidal
Frontoethmoidal
Nasal

20. Encephaloceles
Parietal encephalocele
Frontoethmoidal encephalocele

21. Encephaloceles Clinical Depends on involvement Treatment
Surgical excision of sac with water-tight dural closure

22. Anencephaly
1/1000
Anencephaly is a defect in the closure of the neural tube during fetal development.
Large defect of the calvarium, meninges, and scalp.
Incompatible with life.

23. Anencephaly

24. Corpus Callosum Agenesis
Expansion of third ventricle
May present with HCP, seizures
May be incidental finding without any clinical significance

25. Spinal Dysraphism (spina bifida)
Spina bifida occulta: 20-30% in North Americans, often incidental, cutaneous manifestations
Spina bifida aperta:
Meningocele
Myelomeningocele

26. Spinal Dysraphism
Spina bifida occulta

27. Spinal Dysraphism
Meningocele

28. Spinal Dysraphism
Myelomeningocele

29. Meningocele 1-2/1000 1/3 have neurological deficits
Surgical repair with water-tight dural closure

30. Meningomyelocele 1-2/1000 live birth
Failure of complete closure of caudal neural tube
85% occur in lumbar region

31. Meningomyelocele

32. Meningomyelocele

33. Myelomeningocele Clinical Mild to complete LE paralysis
Ruptured vs unruptured
Urinary incontinence
Skeletal abnormalities

34. Myelomeningocele Treatment Prone wet gauze over lesion
Surgical closure within 36hrs
Shunt if overt HCP
Urologic and Orthopaedic consultation

35. Lipomyelomeningocele
Present with back mass, bladder problems, paralysis
Cutaneous stigmata
Symptoms are due to tethered cord and cord compression from fatty mass
Treatment is surgical decompression

36. Tethered Cord Syndrome
Anatomy
Low conus medullaris
Short, thick filum terminale
Intradural lipoma

37. Tethered Cord Syndrome

38. Tethered Cord Syndrome
Clinical
Cutaneous findings
Gait difficulties
Visible muscle atrophy
LE sensory deficits
Bladder dysfunction
Scoliosis

39. Tethered Cord Syndrome
Treatment
Laminectomy with division of filum terminale
Removal of lipoma if present
Followed with MRI