11-25 Pedi Neurosurg Flashcards
3 general types of spina bifidia (wiki)
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Myelomeningocele
both spinal cord/cauda equina AND dura are outside the body
—caused by Incomplete closure of neural tube
, meningocele
only the dura is in the cyst
, myelocystocele
—error in secondary neurulation
, lipomyelomeningocele
—fat grows into spine cord area
—caused by early disjunction in secondary neurulation
, split cord malformation
look up
, dermal sinus
—Incomplete disjunction of ectoderm
—can present on exam as deep dimple within gluteal fold
, tethered spinal cord
several causes including: Tight filum terminale, Lipomeningomyelocele, Split cord malformations, Dermal sinus tracts, others
—all involve the pulling of the spinal cord at the base of the spinal canal
spina bifida occulta
the outer part of some of the vertebrae is not completely closed splits are so small that cord doesn’t protrude
—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
—10-20% of population have it!
—usually benign
symptoms of tethering
—bowel/bladder dysfunction
—orthopedic deformity (e.g. high arches, hammertoes)
—weakness
—progressive scoliosis
—back pain (rare in kids, so investigate)
neurulation time marks (just get the gist)
POD* 16 - neural plate induced POD 17 – neural groove forms POD 24 - ant neuropore closes POD 26 – caudal neuropore closes POD 27 – secondary neurulation – starts *post ovulation day
dimples on babies backs
be worried if ABOVE the gluteal fold (ass crack)
—below gluteal fold common and likely benign (though could be communication called “dermal sinus”)
primary neurulation
cells surrounding the neural plate direct the neural plate cells to proliferate, invaginate, and pinch off from the surface to form a hollow tube
secondary neurulation
the neural tube arises from a solid cord of cells that sinks into the embryo and subsequently hollows out (cavitates) to form a hollow tube.
folic acid recommendations
—400 mcg/day in all women of child-bearing age
—4000 mcg/day in women w/ previous child w/ neural tube defect (may be enzymatic abnormality in the folic acid pathway)
normal level of the end of the conus medularis
~L1
Why do 80% of kids w/ spina bifida need a shunt?
—spina bifida causes obstruction (e.g. deformity tugs downward on cord) of CSF outflow
—hydrocephalus develops —> resp failure if bad
Where is CSF made?
Choroid plexus makes about 70% of spinal fluid; rest is transudate from ependyma
Chemistry ∆s between CSF & plasma?
CSF has 2/3 serum glucose
—similar sodium and chloride content
Functions of CSF
—Cleansing - wash away potentially noxious byproducts of metabolism
—Communication - proteins may play a role in cellular communication. Variation in proteins (such as APP) correlate with ventricular size
—Protection - protects and cushions the brain
—Cushioning - pressure dampening of the pulse wave from blood vessels (if not there to do so, syrinx can develop)
causes of hydrocephalus outside the head?
hepatitis—drainage of CSF thru choroid plexus is PASSIVE, therefore incr CVP decr gradient between CSF and venous system decr’ing the amount of CSF that can passively drain into venous system
categories of hydrocephalus
- Obstructive (Blockage of CSF flow)
- Communicating (Poor reabsorption of CSF)
- Overproduction of CSF (Rare, e.g. Choroid plexus papilloma)
s/sx of hydrocephalus
Headache, lethargy, blurry vision, emesis, obtundation, lack of upward gaze
ETV tx for hydrocephalus
endoscopic third ventriculostomy;
—better outcomes than shunt (fewer need of repeat surg to fix occluded catheter)
dystonia vs. spasticity
spasticity = resistance to passive mov't dystonia = random, uncontrolled mov'ts
surgical tx options for spasticity
Selective Dorsal Rhizotomy, baclofen pump, deep brain stimulation in globus pallidus interna
Chiari malformation - general definition
cerebellar tonsils below the foramen magnum
Chiari I vs. Chiari II malformation
Chiari I = Cerebellar tonsils > 5mm below foramen magnum
Chiari II = Descent of cerebellar vermis; Brainstem herniates through foramen magnum; Only in patients with myelomeningocele
S/Sx Chiari I
—Occipital, valsalva (i.e. exercise) induced headache
—Cranial neuropathy
—Cord dysfunction
—Syrinx
S/Sx Chiari II
Respiratory distress in an infant
—Headache or brainstem dysfunction in older kid
When do to Chiari surg?
Many do not need surgery (often incidental finding on head imaging for other reason)
—Surgical can help if patient has sx
Surg options for epilepsy
Grid placement with tailored cortical resection and brain mapping
—Functional hemispherectomy, corpus callosotomy
—Vagal nerve stimulator
