COMMON CONGENITAL NEUROSURGICAL DISEASES Essam Elgamal 1

2Outline Approach to Congenital Neurosurgical Diseases Approach to Congenital Neurosurgical Diseases Development of the Nervous System Development of the Nervous System Congenital Malformations Congenital Malformations Neural Tube Defect Neural Tube Defect Congenital Hydrocephalus Congenital Hydrocephalus Arnold Chiari Malformation Arnold Chiari Malformation Dandy-Walker Cyst Dandy-Walker Cyst Arachnoid Cyst Arachnoid Cyst Craniosynostosis Craniosynostosis Neurocutaneous Syndromes Neurocutaneous Syndromes

3 What can go wrong with the brain? Abnormal development Abnormal development Pernatal Events Pernatal Events Abnormal functioning Abnormal functioning Abnormal programming Abnormal programming Neural Tube Defects Neural Tube Defects Neuromigrational Disorders Neuromigrational Disorders Cerebral palsy Cerebral palsy Seizures & Epilepsy Seizures & Epilepsy Hydrocephalus Hydrocephalus Neurofibromatosis Neurofibromatosis Tuberous Sclerosis Tuberous Sclerosis Sturge-Weber Syndrome Sturge-Weber Syndrome Mitochondrial Disorders Mitochondrial Disorders

4 Development of the Nervous System

5 Gross Development Ectoderm Ectoderm  Will form nervous system and outer skin Endoderm Endoderm  Will form skeletal system and voluntary muscle Mesoderm Mesoderm  Will form gut and digestive organs

6 Developmental Sequence Neural plate invaginates as neural folds push up Neural plate invaginates as neural folds push up Neural folds eventually form neural groove Neural folds eventually form neural groove Cells of neural fold eventuall meet Cells of neural fold eventuall meet Form the neural tube Form the neural tube

7 Developmental Sequence Neural tube runs anterior – posterior along embryo Neural tube runs anterior – posterior along embryo Surrounding ectoderm eventually encloses neural tube Surrounding ectoderm eventually encloses neural tube When neural tube closes off brain and spinal cord are formed When neural tube closes off brain and spinal cord are formed

8 Human Embryo Primitive brain consists of 3 cavities that will form ventricles Primitive brain consists of 3 cavities that will form ventricles Brain’s gross features are then formed through a series of bends Brain’s gross features are then formed through a series of bends

9 Human Embryo Developing embryo Developing embryo Goes through a series of folds or “flexures” Goes through a series of folds or “flexures” Gives rise to the compact structure of the brain Gives rise to the compact structure of the brain BrainDiencephalonMidbrain

10 Congenital Malformations Neural Tube Defects (Dysraphism)

11Pathophysiology Spina bifida occulta Spina bifida occulta 5-10% of population 5-10% of population not clinically significant not clinically significant tuft of hair, dimple sinus or port wine stain tuft of hair, dimple sinus or port wine stain high incidence of underlying defect high incidence of underlying defect no treatment required, U/S or MR no treatment required, U/S or MR

12Pathophysiology The openings at each end are termed the rostral and caudal neuropores, and close at around the 24 th and 27 th days respectively The openings at each end are termed the rostral and caudal neuropores, and close at around the 24 th and 27 th days respectively If the neural folds do not fuse at the rostral end, anencephaly results If the neural folds do not fuse at the rostral end, anencephaly results If the neural folds do not fuse at the caudal end, myeloschisis (cleft spinal cord) results (the most severe form of spina bifida) If the neural folds do not fuse at the caudal end, myeloschisis (cleft spinal cord) results (the most severe form of spina bifida)

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15 Failure of vertebral arch bony growth and fusion.Failure of vertebral arch bony growth and fusion. Neurologic symptoms are usually absent, although problems may occur during growth owing to "tethering" of the spinal cord.Neurologic symptoms are usually absent, although problems may occur during growth owing to "tethering" of the spinal cord. Skin anomalies frequently overlie the defect, including a hairy patch, hemangioma, or dermal sinusSkin anomalies frequently overlie the defect, including a hairy patch, hemangioma, or dermal sinus Meninges bulge through the defect Spinal cord and its nerves enter the defect Neural tissue is directly exposed

16 Multiple factors implicated: Multiple factors implicated:  Radiation & chemicals  Drugs  Malnutrition  Genetic determinants (mutations in folate-responsive or folate-dependent pathways)

17 Diagnosis Maternal Alpha Fetoprotein Maternal Alpha Fetoprotein  AFP leaks into amniotic fluid, and then into maternal blood  Blood level taken weeks gestation is used as a screening test; Amniocentesis Amniocentesis  at around 18 weeks, allows detection of over 99 percent of foetuses with neural tube defects Ultrasound Ultrasound MRI MRI

18 Associated anomalies Assess for presence & severity of Assess for presence & severity of  Chiari Malformation  Hydrocephalus  Associated brain malformations  Extremity deformities: contractures  Congenital kyphosis and/or scoliosis  Other abnormalities (renal, bowel, bladder, cardiac)

19 Chiari II Malformation Cerebellar Herniation plus Medulla distortion and dysplasiaCerebellar Herniation plus Medulla distortion and dysplasia Seen in >50% of children with lumbar myelomeningocoelesSeen in >50% of children with lumbar myelomeningocoeles Hydrocephalus results from aqueduct stenosis or an obstruction of outflow of CSF from 4 th ventricle secondary to herniationHydrocephalus results from aqueduct stenosis or an obstruction of outflow of CSF from 4 th ventricle secondary to herniation Symptoms of raised ICP, oropharyngeal dysfunction, cranial nerve palsies, cardiorespiratory failureSymptoms of raised ICP, oropharyngeal dysfunction, cranial nerve palsies, cardiorespiratory failure MRIMRI Posterior fossa decompression & VP shuntPosterior fossa decompression & VP shunt Chiari I Malformation Cerebellar herniation through foramen magnumCerebellar herniation through foramen magnum Incidental finding: headache; neck pain; oropharyngeal dysfunctionIncidental finding: headache; neck pain; oropharyngeal dysfunction

20 Further Assessment Latex Allergy Latex Allergy Seizures Seizures Nutrition: obesity or malnutrition Nutrition: obesity or malnutrition VP shunt dysfunction VP shunt dysfunction Psychosocial development Psychosocial development

21 Clinical manifestations Sacral and Low Lumbar (L4, L5) Sacral and Low Lumbar (L4, L5)  Ambulate into adulthood  Ankle/Foot orthoses Mid-lumbar (L3, L4) Mid-lumbar (L3, L4)  Difficulties with ambulation into adulthood  As above plus crutches/walker  Wheelchair for distances High lumbar & Thoracic (L2 & above) High lumbar & Thoracic (L2 & above)  May be trained to ambulate in early childhood  Hip-knee-ankle orthoses  Walker or crutches but most wheelchair-bound

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23 Encephalocele Encephalocele Encephalocele Usually occipital Usually occipital may contain occipital lobe, or cerebellum may contain occipital lobe, or cerebellum often associated with hydrocephalus often associated with hydrocephalus Immediate treatment if ruptured Immediate treatment if ruptured outcome depends upon contents outcome depends upon contents

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25 Congenital Hydrocephalus

26 Enlargement of brain ventricles (internal hydrocephalus) and/or subarachnoid spaces (external hydrocephalus), associated with increased ICP. The incidence 0.9 and 1.8/1000 live births. Definition

27 RATIONALE CSF secretion is an active process. 70% by ventricular choroid plexuses, 30% by extrachoroid sources capillary ultrafiltrate, ependyma, metabolic water production rate of production is 0.35 ml/min or 500 ml/day.

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29 CSF is passively absorbed by: arachnoid villi into venous dural sinuses other pathways of absorption: spine venous plexuses. perivascular and the perineural sheaths.

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31 PATHOPHYSIOLOGY 1. CSF overproduction: hypervitaminosis A, choroid plexus tumors. 2. Obstruction to CSF flow. ventricular dilatation generates mechanical damages to the parenchyma.

32 Clinical manifestations Infants & young children: 1. Increasing head circumference. 2. Irritability, lethargy, poor feeding, and vomiting. 3. Bulging anterior fontanelle. 4. Widened cranial sutures. 5. McEwen's cracked pot sign with cranial percussion. 6. Scalp vein dilation (increased collateral venous drainage). 7. Sunset sign (forced downward deviation of the eyes, a neurologic sign almost unique with hydrocephalus). 8. Epidsodic bradycardia and apnea.

33 Treatment Endoscopic third ventriculostomy CSF diversion: V-P shunt V-A shunt V-Plural shunt V-sinus shunt 33

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36 Chiari malformation 36

37 Dandy-Walker cyst 37

38 Arachnoid cyst 38

39 Craniosynostosiss 39

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45 Neurocutaneous Syndromes Tuberous Sclerosis

46 Neurocutaneous Syndromes Neurofibromatosis Type 1

47 Lisch nodule Café au lait spot Neufibromas

48 Optic glioma

49 Thank you