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NS38 Neurosurgery
Pediatric Neurosurgery Toronto Notes 2019 Craniosynostosis
Definition
• prematureclosureofthecranialsuture(s)
Classification
• sagittal(mostcommon):longnarrowheadwithridgingsagittalsuture(scaphocephaly) • coronal:expansioninsuperiorandlateraldirection(brachiocephaly)
• metopic(trigonocephaly)
• lambdoid:leastcommon
Epidemiology
• 0.6/1,000livebirths,mostcasesaresporadic;familialincidenceis2%ofsagittaland8%ofcoronal synostosis
Clinical Features
• skulldeformity,raisedICP±hydrocephalus
• ophthalmologicproblemsduetoincreasedICPorbonyabnormalitiesoftheorbit • mustdifferentiatebetweenpositionalplagiocephaly(secondarytobacksleeping)
Investigations
• plainradiographs,CTscan
Treatment
• parentalcounsellingaboutnatureofdeformity,associatedneurologicalsymptoms
• surgeryforcosmeticpurposes,exceptincasesofelevatedICP(≥2suturesinvolved)
Pediatric Brain Tumours
• seeTumours,NS11
Epidemiology
• 20%ofallpediatriccancers(secondonlytoleukemia)
• 60%ofpediatricbraintumoursareinfratentorial
• pediatricbraintumoursarisefromvariouscellularlineages
• glia:low-gradeastrocytoma(supra-orinfratentorial),anaplasticastrocytoma,glioblastomamultiforme
(largely supratentorial) (see Astrocytoma, NS13)
• primitivenervecells:supratentorialPNET
• 90%ofneonatalbraintumours,infratentorial(medulloblastoma),pinealgland(pineoblastoma) • non-neuronalcells:germcelltumour,craniopharyngioma,dermoid,meningioma,neurinoma
(schwanoma), pituitary adenoma, others
Clinical Features
• vomiting, seizure, macrocrania, hydrocephalus
• developmentaldelay,poorfeeding,failuretothrive
• ofteninitiallyescapesdiagnosisduetoexpansilecraniumandneuralplasticityinchildren
Table 24. Overview of Childhood Primary Brain Tumours*
Most Common Pediatric Brain Tumours
Astrocytoma, low grade Supratentorial Infratentorial Medulloblastoma Ependymoma Glioblastoma
Pilocytic (low grade) Astrocytoma Medulloblastoma
Ependymoma Hemangioblastoma
Craniopharyngioma
Usually in posterior fossa Well circumscribed Benign, good prognosis
A primitive neuroectodermal tumour (PNET)
In cerebellum → compresses 4th ventricle → hydrocephalus Highly malignant
In 4th ventricle → hydrocephalus Poor prognosis
Often cerebellar
Associated with von Hippel-Lindau syndrome with retinal angiomas Can produce EPO → secondary polycythemia
Causes bitemporal hemianopsia (thus often confused with pituitary adenoma) Most common supratentorial childhood tumour
Benign
* See also, Familial Cancer Syndromes, Medical Genetics, MG7