Disorders of Neural Tube Disorders of Neural Tube ClosureClosure
Jan M. Eckermann, MD, PGY-3Jan M. Eckermann, MD, PGY-3
Department of NeurosurgeryDepartment of Neurosurgery
Loma Linda University Medical Loma Linda University Medical CenterCenter
Review of NeuroembryologyReview of Neuroembryology
• Dorsal inductionDorsal induction
• Primary neurolation: 3-4 wks Primary neurolation: 3-4 wks gestation Brain and upper spinegestation Brain and upper spine
• Secondary neurolation: 4-5 wks Secondary neurolation: 4-5 wks gestation Distal spinegestation Distal spine
Neural grooveNeural groove
Neural tubeNeural tube
Whereyouat??Whereyouat??
Disorders of neural tube Disorders of neural tube closureclosure• Chiari I-IVChiari I-IV
• EncephalocelesEncephaloceles
• AnencephalyAnencephaly
• Corpus Callosum AgenesisCorpus Callosum Agenesis
• Spinal Dysraphism (Spina bifida)Spinal Dysraphism (Spina bifida)
• - Menigoceles- Menigoceles
• - Myelomeningoceles- Myelomeningoceles
• Tethered chordTethered chord
Chiari IChiari I
ANATOMYANATOMY
• Peglike cerebellar tonsils displaced Peglike cerebellar tonsils displaced into upper cervical canal ( >10mm)into upper cervical canal ( >10mm)
• HCP 25%HCP 25%
• Syringomyelia 60%Syringomyelia 60%
• Skeletal anomalies 25%Skeletal anomalies 25%
Chiari I: displaced tonsilsChiari I: displaced tonsils
Chiari I: syringomyeliaChiari I: syringomyelia
Chiari I: syringomyeliaChiari I: syringomyelia
Chiari IChiari I
ClinicalClinical
• Asympotmatic (30%)Asympotmatic (30%)
• HeadacheHeadache
• WeaknessWeakness
• Cerebellar signsCerebellar signs
• Herniation >12mm invariably Herniation >12mm invariably symptomaticsymptomatic
Chiari IChiari I
TreatmentTreatment
• Observation if asymptomaticObservation if asymptomatic
• Surgery if symptomatic: p-fossa Surgery if symptomatic: p-fossa decompression +- cervical decompression +- cervical laminectomylaminectomy
Whereyouat??Whereyouat??
Chiari IIChiari II
AnatomyAnatomy
• Calvarial defects “Lueckenschaedel”Calvarial defects “Lueckenschaedel”
• Small p-fossaSmall p-fossa
• Fenestrated falxFenestrated falx
• HCP in 90%HCP in 90%
• Myelomeningocele in 100%Myelomeningocele in 100%
• Syringohydromyelia in 50%-90%Syringohydromyelia in 50%-90%
Chiari II: Brain MRIChiari II: Brain MRI
Chiari II: lueckenschaedel, Chiari II: lueckenschaedel, falxfalx
Chiari IIChiari II
ClinicalClinical
• DysphagiaDysphagia
• Apneic spellsApneic spells
• StridorStridor
• AspirationAspiration
• Arm weaknessArm weakness
Chiari IIChiari II
TreatmentTreatment
• ShuntShunt
• P-fossa decompressionP-fossa decompression
• Repair of MMRepair of MM
Chiari III and IVChiari III and IV
Chiari IIIChiari IIIMost severe form. Chiari II + low occiptial or Most severe form. Chiari II + low occiptial or
high cervical encephalocele. Usually high cervical encephalocele. Usually incompatible with lifeincompatible with life
Chiar IVChiar IVSevere cerebellar hypoplasia or absence. No Severe cerebellar hypoplasia or absence. No
herniationherniationExtremely rareExtremely rare
Whereyouat??Whereyouat??
EnephalocelesEnephaloceles
• AnatomyAnatomy
• Failure of the anterior neural tube to Failure of the anterior neural tube to close due to genetic, infection, or close due to genetic, infection, or toxic reasons.toxic reasons.
• 1/10001/1000
• Distorted parts of the (covered) brain Distorted parts of the (covered) brain protruding extracalvariallyprotruding extracalvarially
EncephaloceleEncephalocele
AnatomyAnatomy
Occipital 90%Occipital 90%
Parietal 10%Parietal 10%
TranssphenoidalTranssphenoidal
Frontoethmoidal Frontoethmoidal
NasalNasal
EncephalocelesEncephaloceles
• Parietal Parietal encephaloceleencephalocele
• Frontoethmoidal Frontoethmoidal encephaloceleencephalocele
EncephalocelesEncephaloceles
• ClinicalClinical
Depends on involvement Depends on involvement
• TreatmentTreatment
Surgical excision of sac with water-Surgical excision of sac with water-tight dural closuretight dural closure
AnencephalyAnencephaly
• 1/1000 1/1000
• Anencephaly is a defect in the Anencephaly is a defect in the closure of the neural tube during closure of the neural tube during fetal development.fetal development.
• Large defect of the calvarium, Large defect of the calvarium, meninges, and scalp.meninges, and scalp.
• Incompatible with life.Incompatible with life.
AnencephalyAnencephaly
Corpus Callosum AgenesisCorpus Callosum Agenesis
• Expansion of third ventricleExpansion of third ventricle
• May present with HCP, seizuresMay present with HCP, seizures
• May be incidental finding without any May be incidental finding without any clinical significanceclinical significance
Whereyouat??Whereyouat??
Spinal Dysraphism (spina Spinal Dysraphism (spina bifida)bifida)
• Spina bifida occulta:Spina bifida occulta: 20-30% in North 20-30% in North Americans, often incidental, Americans, often incidental, cutaneous manifestationscutaneous manifestations
• Spina bifida aperta:Spina bifida aperta:
• Meningocele Meningocele
• MyelomeningoceleMyelomeningocele
Spinal DysraphismSpinal Dysraphism
• Spina bifida occultaSpina bifida occulta
Spinal DysraphismSpinal Dysraphism
• MeningoceleMeningocele
Spinal DysraphismSpinal Dysraphism
• MyelomeningoceleMyelomeningocele
MeningoceleMeningocele
• 1-2/10001-2/1000
• 1/3 have neurological deficits1/3 have neurological deficits
• Surgical repair with water-tight dural Surgical repair with water-tight dural closureclosure
MeningomyeloceleMeningomyelocele
• 1-2/1000 live birth1-2/1000 live birth
• Failure of complete Failure of complete closure of caudal closure of caudal neural tubeneural tube
• 85% occur in 85% occur in lumbar regionlumbar region
MeningomyeloceleMeningomyelocele
MeningomyeloceleMeningomyelocele
MyelomeningoceleMyelomeningocele
• ClinicalClinical
• Mild to complete LE paralysisMild to complete LE paralysis
• Ruptured vs unrupturedRuptured vs unruptured
• Urinary incontinenceUrinary incontinence
• Skeletal abnormalitiesSkeletal abnormalities
MyelomeningoceleMyelomeningocele
• TreatmentTreatment
• If open, Gent and Naf IVIf open, Gent and Naf IV
• Prone, bottom upProne, bottom up
• Telfa with wet gauze over lesionTelfa with wet gauze over lesion
• Surgical closure within 36hrsSurgical closure within 36hrs
• Shunt if overt HCPShunt if overt HCP
• Urologic and Orthopaedic consultationUrologic and Orthopaedic consultation
LipomyelomeningoceleLipomyelomeningocele
• Present with back mass, bladder Present with back mass, bladder problems, paralysisproblems, paralysis
• Cutaneous stigmataCutaneous stigmata
• Symptoms are due to tethered cord Symptoms are due to tethered cord and cord compression from fatty and cord compression from fatty massmass
• Treatment is surgical decompressionTreatment is surgical decompression
Whereyouat??Whereyouat??
Tethered Cord SyndromeTethered Cord Syndrome
• AnatomyAnatomy
• Low conus medullarisLow conus medullaris
• Short, thick filum terminaleShort, thick filum terminale
• Intradural lipomaIntradural lipoma
Tethered Cord SyndromeTethered Cord Syndrome
Tethered Cord SyndromeTethered Cord Syndrome
• ClinicalClinical
• Cutaneous findingsCutaneous findings
• Gait difficultiesGait difficulties
• Visible muscle atrophyVisible muscle atrophy
• LE sensory deficitsLE sensory deficits
• Bladder dysfunctionBladder dysfunction
• ScoliosisScoliosis
Tethered Cord SyndromeTethered Cord Syndrome
• TreatmentTreatment
• Laminectomy with division of filum Laminectomy with division of filum terminaleterminale
• Removal of lipoma if presentRemoval of lipoma if present
• Followed with MRIFollowed with MRI
Thank youThank you