30. Pediatric Neurosurgery Flashcards
define myelomeningocele
incomplete closure of neural tube. most significant/common form of spina bifida. problem of PRIMARY neurulation
define spinal bifida
incomplete closing of the embryonic neural tube. some vertebrae are incompletely formed, and spinal cord protrudes through the opening in the bones.
define meningocele. vertebrae? meninges? prognosis?
aka meningeal cyst. least common form of spina bifida. Vertebrae develop normally, but the meninges are forced into the gaps between the vertebrae. Nervous system remains undamaged so individuals with meningocele are unlikely to suffer long-term health problems, although cases of tethered cord have been reported.
define myelocystocele
Problem with SECONDARY neurulation. spinal bifida where some of the spinal cord and meninges protrudes through the opening. Fluid collection.
define tethered cord
Involves the pulling of the spinal cord at the base of the spinal canal, literally a tethered cord. The spinal cord normally hangs loose in the canal, free to move up and down with growth, and with bending and stretching. A tethered cord is held taut at the end, or some point in the spinal canal. In children, a tethered cord can force the spinal cord to stretch as they grow.
define lipomyelomeningocele
a fatty mass covered in skin that is attached to the spinal cord. early disjunction of cutaneous and neural ectoderm.
Define split cord malformation
spinal bifida with longitudinal split in cord
define dermal sinus
incomplete disjunction of ectoderm.
connection from skin into spinal cord. risk for meningitis.
define spinabifida occulta
Mildest form of spina bifida. The outer part of some of the vertebrae is not completely closed. The splits in the vertebrae are so small that the spinal cord does not protrude. The skin at the site of the lesion may be normal, or it may have some hair growing from it; there may be a dimple in the skin, or a birthmark. Usually asx.
symptoms of tethered spinal cord?
bowel/bladder dysfunction, orthopedic deformity (hammertoes, high arch), weakness, progressive scoliosis, back pain (back pain in a child is rare, should be looked at)
how much CSF does an adult have?
150 cc
how much CSF does an adult make daily?
450cc because the 150 cc turns over 3x/day
where is CSF made?
70% choroid plexus, rest is a transudate from ependyma (lining of ventricles and spinal cord)
primary neurulation creates what
develops brain and spinal cord to S2
what day does secondary neurulation start?
post-ovulation day 27
what is the timing of primary neurulation? (on what PODs do things happen?)
POD 16: neural plate induced POD 17: neural groove forms above notochord POD 24: anterior neuropore closes POD 26: caudal neuropores POD 27: secondary neurulation starts
defects caused by defects in secondary neurulation?
- abnormal filum terminale
- terminal lipoma
- myelocystocele
folic acid: how much recommended per day for child-bearing aged women?
400 microgram/day
folic acid: how much recommended per day for child-bearing aged women with prior child having neural tube defect?
4000 microgram/day. there may be an enzymatic abnormality in the folic acid pathway.
MOMS trial: what were they comparing?
prenatal surgery vs postnatal repair of myelomeningocele.
MOMs trial: results?
improved mental dev and motor function at 30 months in PREnatal group
no difference in cognitive scores between groups
but prenatal group had more complications, born preterm.
80% of kids with spina bifida also have what? therefore need what?
also have hydrocephalus. mech: spinal cord slightly lower, may cause brainstem/cerebellum to herneate, closing flow of CSF.
therefore need a shunt.
Three types of hydrocephalus?
- obstruction
- communicating
- overproduction
define obstructive hydrocephalus
blockage of CSF flow
define communicating hydrocephalus
poor reabsorption of CSF
define overproduction hydrocephalus
rare, choroid plexus papilloma
how does CSF content compare with serum levels for glucose, sodium, chloride?
CSF has 2/3 serum glucose
same sodium, same chloride
generally, circulation of CSF?
lateral ventricles –> third ventricles –> fourth ventricle –> behind cerebellum -> arachnoid granules between arachnoid and dura
biggest signs of hydrocephalus in children?
incr head circumference, bulging fontanelle, delayed development, loss of upward gaze, lethargy, papilledema
symptoms of hydrocephalus in children?
irritability, n/v, headache, lethargy
three treatments for hydrocephalus?
- ventriculoperitoneal shunt
- endoscopic third ventriculostomy
- choroid plexus cauterization
endoscopic third ventriculostomy: what is it?
endoscope into lateral ventricle, scope drive through foramen of monroe and floor of third ventricle is punctured.
endoscopic third ventriculostomy: outcomes
96% success for aqueductal stenosis. better if also do choroid plexus cauterization
shunt: outcomes
infection rate 5-12%. shunt will eventually get clogged up with debris, will have to replace.
use ETV first to avoid these problems.
define Chiari I malformation
cerebellar tonsils > 5mm below foramen magnum
define Chiari II malformation
Spina bifida only: pts with myelomeningocele. brainstem herniates through foramen magnum
symptoms for Chiari I malformation?
occipital, exercise induced headache
cranial neuropathy
cord dysfunction
syrinx (collection of CSF into cyst)
Symptoms for Chiari II malformation?
resp distress in infant
headache or brainstem dysfunction in older kid
treatment for Chiari malformations?
many do not need treatment; surgery if sx need to be treated
definition of spasticity
resistance to passive movement. can get contractures if get stuck in certain postures.
definition of dystonia
neuro movement disorder, sustained contractions cause twisting or repetitive movements or abnl postures
define rhizotomy
selective destruction of problematic nerve roots. can reduce hypersensitivity, which decr spasticity.
