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COMMON CONGENITAL NEUROSURGICAL DISEASES Essam Elgamal 428 surgery team 1 Outline Approach to Congenital Neurosurgical Diseases Development of the Nervous System Congenital Malformations Neural Tube Defect Congenital Hydrocephalus Arnold Chiari Malformation Dandy-Walker Cyst Arachnoid Cyst Craniosynostosis Neurocutaneous Syndromes 2 What can go wrong with the brain? 3 Abnormal development Neural Tube Defects Neuromigrational Disorders Pernatal Events Cerebral palsy Abnormal functioning Seizures & Epilepsy Hydrocephalus Abnormal programming Neurofibromatosis Tuberous Sclerosis Sturge-Weber Syndrome Mitochondrial Disorders Development of the Nervous System 4 Gross Development Ectoderm Will form nervous system and outer skin Endoderm Will form skeletal system and voluntary muscle Mesoderm Will form gut and digestive organs 5 Developmental Sequence Neural plate invaginates as neural folds push up Neural folds eventually form neural groove Cells of neural fold eventuall meet Form the neural tube 6 Developmental Sequence Neural tube runs anterior – posterior along embryo Surrounding ectoderm eventually encloses neural tube When neural tube closes off brain and spinal cord are formed 7 Human Embryo Primitive brain consists of 3 cavities that will form ventricles Brain’s gross features are then formed through a series of bends 8 Human Embryo Developing embryo Goes through a series of folds or “flexures” Gives rise to the compact structure of the brain Brain Diencephalon Midbrain 9 Congenital Malformations Neural Tube Defects (the most common defect) (Dysraphism) 10 Pathophysiology Spina bifida occulta (closed) 11 5-10% of population 1/1000 in US, 2/1000 in ksa not clinically significant tuft of hair, dimple sinus or port wine stain high incidence of underlying defect no treatment required just to cover it, U/S or MR Pathophysiology The openings at each end are termed the rostral and caudal neuropores, and close at around the 24th and 27th days respectively 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) treated as an emergency case, just few hour after delivery 12 anencephaly 13 If it doesn’t get closed = myeloschisis 14 •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. •Skin anomalies frequently overlie the defect, including a hairy patch, hemangioma, or dermal sinus Same as B +Spinal cord and its nerves enter the defect 15 Meninges with CSF bulge through the defect coverd by skin Neural tissue is directly exposed Multiple factors implicated: not well understood Folate deficiency (most common cause) (there is no benefit to give folic acid after 24th-27th day) Radiation & chemicals Drugs Malnutrition Genetic determinants (mutations in folate-responsive or folate-dependent pathways) 16 Diagnosis Maternal Alpha Fetoprotein AFP leaks into amniotic fluid, and then into maternal blood in case of open spina bifida Blood level taken 13-16 weeks gestation is used as a screening test; Amniocentesis at around 18 weeks, allows detection of over 99 percent of fetuses with neural tube defects Ultrasound MRI U.S is the first way to detect neural tube defect 17 M.R.I is the confirmatory method to detect neural tube defect Associated anomalies Assess for presence & severity of 18 Chiari Malformation Hydrocephalus Associated brain malformations Extremity deformities: contractures Congenital kyphosis and/or scoliosis Other abnormalities (renal, bowel, bladder, cardiac) Chiari II Malformation •Cerebellar tonsil Herniation plus Medulla distortion and dysplasia • Seen in >50% of children with lumbar myelomeningocoeles •Hydrocephalus results from aqueduct stenosis or an obstruction of outflow of CSF from 4th ventricle secondary to herniation •Symptoms of raised ICP, oropharyngeal dysfunction, cranial nerve palsies, cardiorespiratory failure •Dx by MRI •Rx by Posterior fossa decompression & VP shunt Chiari I Malformation •Cerebellar herniation through foramen magnum •Incidental finding: headache; neck pain; oropharyngeal dysfunction 19 •Diagnosed in adulthood Further Assessment Latex Allergy (gloves) (all children with spina bifida are considered to have allergy to latex till prove otherwise ) Seizures Nutrition: obesity or malnutrition VP shunt dysfunction Psychosocial development 20 Clinical manifestations Sacral and Low Lumbar (L4, L5) most common site Ambulate into adulthood Ankle/Foot orthoses (device to support limb function) Mid-lumbar (L3, L4) Difficulties with ambulation into adulthood As above plus crutches/walker Wheelchair for distances High lumbar & Thoracic (L2 & above) May be trained to ambulate in early childhood Hip-knee-ankle orthoses Walker or crutches but most wheelchair-bound 21 22 Encephalocele Encephalocele = A sac with a part of brain but this part doesn’t work Usually occipital may contain occipital lobe, or cerebellum often associated with hydrocephalus Immediate treatment if ruptured to prevent infection outcome depends upon contents Meningeocele in skull = A sac in the skull with no brain 23 24 Congenital Hydrocephalus 25 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. 26 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. 350ml/day reabsorbed 27 QuickTime™ and a Microsoft Video 1 decompressor are needed to see this picture. 28 CSF is passively absorbed by: arachnoid villi into venous dural sinuses other pathways of absorption: spine venous plexuses. perivascular and the perineural sheaths. 29 30 PATHOPHYSIOLOGY 1. CSF overproduction: hypervitaminosis A, choroid plexus tumors. 2. Obstruction to CSF flow. ventricular dilatation generates mechanical damages to the parenchyma. 3- decreased absorption by adhesion (N:B: adhesion occur in case of trauma, infection,& hemorrhage ) 4- DVT in dural veinous sinusis 31 Clinical manifestations depends on age Infants & young children: 32 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. (palpable separation of cranial suture, percussion of the skull evokes a 'jagged' sound) 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 & HTN . Occur later in life Treatment Endoscopic third ventriculostomy CSF diversion: V-P shunt V-A shunt V-Plural shunt V-sinus shunt 33 QuickTime™ and a decompressor are needed to see this picture. 34 35 Chiari malformation type II chiari malformation associated with lumbar myelomeningocoeles and may be ended up with hydrocephalus 36 Dandy-Walker cyst Cyst in cerebellar area no cerebellum = cerebellar agenisis 37 Arachnoid cyst Incidentally Dx, conservative Rx 38 Craniosynostosiss 39 40 41 42 43 44 Neurocutaneous Syndromes Tuberous Sclerosis 45 Neurocutaneous Syndromes Neurofibromatosis Type 1 46 Café au lait spot Neufibromas Lisch nodule 47 Optic glioma 48 Thank you abo-7med 49