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