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M & M conference 10/18/02

M & M conference 10/18/02. Andrea Balazs M.D. Dept. of Pediatrics. Neural Tube Defects. Neurulation Brain and sp.cord formation on the dorsal aspect of the embryo 3 rd – 4 th w of pregnancy

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M & M conference 10/18/02

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  1. M & M conference 10/18/02 Andrea Balazs M.D. Dept. of Pediatrics

  2. Neural Tube Defects Neurulation • Brain and sp.cord formation • on the dorsal aspect of the embryo • 3rd – 4th w of pregnancy • Mesoderm induce the formation of the neural plate from the ectoderm ~18th days of gest. – neural tube - ant. closure 24th day –post.closure 26th day

  3. Caudal neural tube formation 28-32nd day from caudal cell mass - vacuoles - coalesc contact with the central canal - canalization and differentation

  4. Neural tube defects • Craniorachischisis • Anencephaly • Encephalocele • Myelomeningocele

  5. Craniorachischisis totalis Total failure of neurulation Neural plate like structure, no overlying skeleton or skin, occurs on 20-22nd day abortion

  6. Anencephaly • Failure of the anterior neural tube closure • Degenarated mass of neurons, glia, vessels • Froglike appearance • Occurs on 24th day • Polyhydramnion • 75% stillborn or die during the neonatal period • Rates of occurrence 0.2/1000 live births

  7. Anencephaly • 4x as frequent in females than in males • Expl.neurulation takes longer, longer vulnerable period

  8. Encephalocele • Herniation of the brain tissue • Location: occipital 70-80%, frontal / temporal / parietal – less common • Protruding mass - occipital lobe / cerebellum • 50 % complicated with hydrocephalus • low occipital or high cervical EC combined with vertebra, skull base and lower brain stem anomaly compose Arnold - Chiari III

  9. Encephalocele • Partial or complete agenesis of corpus callosum • Venous drainage anomaly • Occures before 26th day • EC associated with visual problem,microcephaly, MR and seizure

  10. Meningocele – 10 - 20%, no neural element,usually no neurologic deficit • Outcome more favorable in anterior EC (mortality 0% vs 45%, nl.outcome 42% vs 14%) • Thx: surgery

  11. Myelomeningocele • Failure of the posterior neural tube closure • 80% in the lumbar region • variable dermal covering • dorsal displacement of the neural tissue, CSF leakage, sac formation • neural plate or neural tube-like structure, raw,velvety,flat • ventral part of the cord less affected • Axial skeleton deficiency: lack of fusion or absence of the vertebral arches, widened spinal canal

  12. Myelomeningocele • Onset no later than 26th days • Overall incidence 1:1000 live births ’89 • Risk of recurrence 3% after one affected child, 10% with 2 previous abnormal pregnancies

  13. Myelomeningocele Clinical features: • Lesion itself • disturbances of neurological function pending on the level (motor, sensory, and sphincter function) • Low sacral lesions: bowel and bladder incontinence and anesthesia in the perineal area • Lesions below S1 able to walk unaided • Lesion above L2 wheelchair, later scoliosis, as well

  14. Myelomeningocele • Intermediate/midlumbar lesion L3 – L4 or L5 • Flaccid paralysis of the LE’s, absence of deep tendon reflexes • Lack of response to touch and pain • Clubfeet, hip subluxation • Continuous urinary dribbling and relaxed anal sphincter • ambulatory or primarily ambulatory with braces or cruthces

  15. Myelomeningocele • Deterioriation to a lower level of ambulatory function than that expected from segmental level over time • Hydrocephalus incidence 60% vs 90% • HC > 90% ventriculomegaly in 95% • AF, sutures status • S/s of hydrocephalus is overt by 2-3 weeks of life

  16. Arnold –Chiari II malformation accompanies thoracolumbar - lumbosacral MMC Sequence of events MMC - CSF leakage - lack of normal distension of the ventricles - small posterior fossa - inferior displacement of the medulla, IV th ventricle and cerebellum elongation, thinning of the medulla and pons kinking of the cervical cord obstructed CSF flow - aquaeductus sten. and hydrocephalus

  17. Clinical features associated with A-C II malformation: • brain stem dysfunction –feeding disturbances (reflux, aspiration), dysphagia, apnoe, stridor, cyanotic spells onset at 3.2 months causes: brain stem malformation and displacement affects the cranial nerves and nuclei these structures under compression from the hydrocephalus and the increased ICP ischemic and hemorrhagic necrosis of the brain stem from the disturbed arterial architecture and caudally displaced vertebrobasilar circulation

  18. Other anomalies of the CNS associated with MMC: Abnormal cortical development: Microgyria 55-95% intellectual deficits and seizures Impaired neuronal migration Falx cerebri hypoplasia, septum pellucidum Anomalies Cerebellar dysplasia

  19. Management • Prevention • Prenatal therapy • Human fetal surgery • Optimal means of delivery of the affected infants -c/s vs vag. - paralysis level 3.3 segments below the anatomical level of the lesion to compare with 1.1 for babies delivered vag. - amb. or wheelch. • Postnatal surgery - early closure - proph. Abx – VP shunt placement

  20. Management • Team approach – specialties PE : • Correlate the functional level (motor, sensory and sphincter function and reflexes ) to the level of anatomic lesion • Neurologic dysfunction correlates with the level of the spinal cord lesion • Presence of anal wink and anal sphincter tone suggest functioning sacral spinal segments, prognostically important • evaluate for other malformation

  21. Hydrocephalus – VP shunt – IQ better preserved • Earlier shunt placement improves the cognitive outcome - degree of ventriculomegaly in utero or the size of the cerebral mantle during the 1st week correlates with the subsequent intelligence • Shunt complications - deleterious effect on intellectual outcome • Mean IQ – MMC + infected VP shunt 73 / vs MMC + VP shunt w/o infection 95 • MMC w/out hydrocephalus mean IQ 102

  22. Rare VP shunt complication Migration of the VP shunt tip through the patent processus vaginalis resulting in scrotal hydrocele

  23. Complications in MMC Orthopedic problems • Lower extremities lack innervation – atrophied foot, knee, hip and spine deformities – result from muscle imbalance, abn. In utero positioning • Hip dislocation/subluxation in 1 year mostly with midlumbar MMC • contractures

  24. Complications in MMC Urinary tract abnormalities • Major cause of death after the 1st year • > 85% MMC located above S2 associated with neurogenic bladder • Urinary incontinence and ureteral reflux • Hydronephrosis, chronic pyelonephritis with renal scarring and destruction, urosepsis • Renal anomalies: agenesis, horseshoe k.,ureter duplication

  25. Spina bifida occulta Neural lesions • Myelocystocele –cystic dilatation of the central canal of the caudal neural tube • Diastematomyelia – diplomyelia – spinal cord is bifid, occassionally separated by fibrous or bony septum originating from the vertebra • Lipomeningocele • Epidermoid/dermoid sinus • Tethered cord • Meningocele (anterior, too) • Agenesis of distal spinal cord

  26. Complications in MMC • Outcome of cortical function pending on the level of lesion: • Lumbar MMC nl. range of intelligence • Reading and spelling o.k. • Greatest deficit in arithmetic achievement and visual – motor integration • IQ >80 with lesion below S1 • IQ > 80 in 50% of pt. with thoracolumbar lesion

  27. Spina bifida occulta • Caudal locus L5-S1 • Covered by skin • No neurological deficit • Undetected for years • Abnormal conus med. (prolonged) and filum terminale (thickened) • “Tetherd “ or fixed at their caudal end by fibrous bands,lipoma, dermal sinus

  28. Spina bifida occulta • Vertebra abnormality 85-90% • laminar defects over several segments • Widened spinal canal and sacral deformities • Skin lesion 80% - hair tufts, dimples or tracts, hemangioma, skin tag, cutis aplasia, pigmented macula, sc. Mass, lipoma, dermal sinus (epidermoid,dermoid cyst) • 15-20% infants of diabetic mothers

  29. Spina bifida occulta Clinical aspect • Neurological deficits appear later in infancy • Delay in development of sphincter control, in walking, asymmetry of legs or abn. feet • Pain in the back or lower extremities • Recurrent meningitis • In older child: gait disturbance, foot deformity, scoliosis, abnormal sphincter f.

  30. Spina bifida occulta Management spine x – ray spine US if both nl. And no sy - only clinical F/U if abn. - MRI thx. – surgery in neonatal period to prevent neuro.deficits

  31. New things Fetal surgery • Goal: to prevent damage to the cord and prevent complications related to the primary anomaly, to restore or preserve neurologic function • Done 28-30 w , via hysterotomy • Theoretical advantage of FS: greater potential for healing and regeneration in the fetus • Results: no improvement in motor function • Definite improvement in the cerebellar herniation – A-C III regressed, less likely to require VP shunt – nl.CSF circulation

  32. New things Fetal surgery 2 pt. at risk Induction of early labor, preterm delivery, infection, death MMC is not lethal lesion • Iatrogenic dermoid inclusion cyst in infancy • Progressive neur. deterioriation for spinal cord tethering • Unknown, unforseen complication

  33. Thank you for your attention And Than you for your help Dr. Levin Dr.Quattromani

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