Post Chx Flashcards
Describe the Frissen grading?
Grade II - C shaped halo with temporal gap Grade II - halo becomes circumferential Grade III - loss of major vessels as they leave the disc Grade IV - loss of major vessels on the disc Grade V - criteria of grade IV plus partial or total obscuration of vessels of the disc
What are causes of dural AVF?
Trauma Venous sinus thromobosis Craniotomy Meningioma
What size of colloid cyst should be treated?
1cm (Pollock Mayo series)
What treatment options are there for colloid cyst?
Transcallosal approach (2/3rd in front one front behind) Stereotactic drainage Endoscopic or Open Transventricular
How would you diagnose cushing’s disease?
Differential: pituitary adenoma, ectopic ACTH tumour, adrenal tumour Abdominal tumour
Initial screen - early morning cortisol/24hr urinary cortisol
Low dose dexamethasone suppression test - will only suppress cortisol and ACTH in normal person
High dose dexamethasone suppression test - in 80% of pituitary adenomas will suppress cortisol and ACTH but not in ectopic ACTH secreting tumours
What is the risk of hoarse voice after ACDF?
approx 10% temporary, approx 5% permanent
What is risk of dysphagia after ACDF?
Common immediately but by 6 months only 5% have moderate or severe
Landmarks for Frazier’s burrhole
6cm superior to inion and 3cm lateral
What’s the definition of biochemical cure for acromegaly?
Not-standardised. Greengerg 1) Normal IGF-1 2) Basal (morning) GH <5ng/ml AND nadir <1ng/ml in OGTT
How do you test for remission in cushing’s post op?
Various methods e.g. Early morning cortisol Low dexamethasone suppression test
What classification of Craniopharyngiomas do you know?
Paris classification 1-2 depending on hypothalmic involvement (0 not touching, 1 displaced, 2 infiltrated) 0 can be resected 2 can’t be resected
Describe familial cavernoma syndromes?
CCM1 (KRIT 1) - hispanics CCM2 (Malcavernin) CCM3 (PDCD10)
What is DBX?
Demineralised bone matrix (from cadaveric human donors) - collagen and bone morphogenic proteins
When should you screen for familial cavernoma?
2 first degree relatives with cavernoma
What is cell or origin of craniopharyngioma?
Nests of odontogenic epithelium in pituitary stalk
How do you decide between DBS targets in parkinsons
STN - meds reduction GPi - antidyskinetic effect VIM - tremor control but insufficently addresses other motor feature
What are EMG signs of denervation?
Positive sharp waves Insertional activity Fibrillations (later increased duration and polyphasic waves)
What’s significance of EMG signs of denervation in paraspinal muscles?
Suggests radiculopathy
What do fall in increased latency, fall in conduction velocity and amplitude indicate respectively?
Increased latency or fall in conduction velocity —> demyelination Decreased amplitude –> axonal loss
What screening should you do for VHL?
MRI abdomen - renal, pancreas, adrenal Audiology - endolymphatic sac tumour Eyes - retinal haemangioblastomas Neuraxis screening
urine metanephrines
What AED for this patient for focal epilepsy?
Levetiracetam (Others for focal seizures are carbamazepine or lamotrigine)
What is the mechanism of action of levetiracetam?
It binds SV2A (synaptic vesicle protein) reducing neurotransmitter release
Side effects of levetiracetam?
Somnolence Psychosis Depression
Mechanism of action of phenytoin?
Voltage-dependent sodium channel blockade
Adverse effects of phenytoin
Gingival hyperplasia Rash Bone marrow suppression
What is syndrome of phenytoin toxicity?
Ataxia Nystagmus Slurred Speech Confusion
Describe course of the facial nerve?
Nuclei - motor nucleus, sensory (nucleus solitary tract), Superior salivatory nucleus Leaves pons at level of middle cerebellar peduncle Enters internal auditory canal (7 up coke down) Then there’s the genu of facial canal with geniculate ganglion Branch 1 Gives of GSPN - runs on floor of temporal fossa, enters foramen lacerum and joins lesser petrosal (sympathetics from carotid) to form vidian nerve - pterygopalatine ganglion Branch 2 nerve to stapedius Branch 3 chorda tympani Then leaves through stylomastoid foramen
What is facial colliculus?
Fibres of VII looping over nucleus of VI
What are the segments of PCA?
1 - precommunicationg 2 - ambient 3 - quadigeminal 4 - calcarine
Draw the floor of the fourth ventricle
What are three groups of thalamic nuclei?
Anterior
Lateral
Medial
When is gastrulation?
Pimary neurulation?
Secondary neurulation?
Days’s 14-17
weeks 3-4
weeks 5-6
Pathognomic Path
Pilocytic
Schwannoma
Ependymoma
Chordoma
Pilocytic - Rosenthal fibres
Schwannoma - Antoni A and B fibres, verocay bodies
Ependymoma - pseudorosettres
Chordoma - chords and nests, physallipherous
What are four GBM criteria histology?
Anaplasia
Mitotic Activity
Necrosis
Endothelial/microvascular proliferation
What is marker for ATRT
INI-1 loss
What is significance of ATRX loss?
Defines a subgroup of WHO II tumour with better prognosis
What’s significnace of TP53 mutation
Marker of astrocytoma and GBM
Suggestive not oligodendroglioma
What types of (extra-neural) tumours occur in VHL and TS?
VHL - retinal haemangioblastomas, endolymphatic sac tumours, renal carcinoma, pancreatic carcinoma, (also cysts of both), phaeochromocytoma
TS - cardiac rhabdomyomas, renal angiomyolipoma
How much facet can you take in c spine?
medial 25%
How does gamma knife work?
201 cobalt-60 sources with a collimator
What are four feautres of parinaud’s syndrome?
Collier’s lid retration sign
Lid near dissociation
Convergence nystagmus
Upgaze palsy
What are the muscles overlying posterior fossa?
Superficially
Semispinalis capitis (lateral)
Splenius capitis (medial)
Deeper
Rectus Capitis (medially)
Obliquus Capitis (laterally)
What are differentials for trigeminal neuralgia?
Migraine - Aura, vomiting, photophobia
trigemianal Autonomic cephalgia -
Cluster headache - eye watering, nasal congestion
short-lasting unilateral neuralgiform headache attacks - conjunctival injection tearing
SUNA - short lasting neuralgiform headache (like sunt less prominnent conj injection and tearing)
MS
What are outcomes with RF of gasserian ganglion?
60% patients off meds
80% have numbness
Reduced corneal reflex 7%
What is NICE criteria for decompressive hemicraniectomy in stroke?
A score of 1 of more on alertness component of NIHSS
Signs of infarct on CT of at least 50% MCA territory
(infarct volume greater than 145cm3) on DWI
(ACA and PCA additionally is not a contraindication in NICE)
How do you look left?
Left Parapontine reticular formation stimultates left VIth
and crosses over to right MLF to stimulate right III’d
What was outcome of destingy/decimal/hamlet?
Mortality reduced (71-22%) - extra survivors evenly spread between MRS 2,3 and 4
What were outcome of rescue ICP?
Inclusion Criteria ICP over 25 for 1 hour despite step 1 and step 2 therapy
Mortality reduced(50%–>25%) however increased survivors spread between upper severe, lower severe and vegetative at 6 months
Drugs in status
Lorazepam 4mg/Diazepam 10mg
Phenytoin 20mg/kg
+/-pabrinex +/-dextrose 50ml/50%
How does dexamethasone work?
Downregulates vegf
What drugs can you give for IIH?
Acetazolamide
Topiramate
What electrolytes disturbance to you see from thiopentone?
Hypernatreamia
Hypokalaemia
What is the hierarchy of evidence?
Level 1 - Metanalysis or good RCT
Level 2 - poor rct or Cohort Studies
3 - Case control studies
4 - Case series
5 - expert opinion
What are phases of clinical trials?
Phase 0 - first trials in people
Phase 1 - dosing
Phase 2 - safety and efficacy
Phase 3 - compared to standard of care drug
Phase 4 - post introduction surveillance (report to MHRA via yellow card scheme)
What is the likelihood ratio?
Likelihood ratio = Sensitivity/(1-Specificity)
What is type I error vs type II error?
Type I is falsely positive trial
What drugs can you give in cushings?
metyrapone
(or ketokonazole)
How can you treat SIADH?
Fluid restriction
PO Na, Hypertonic saline
Demeclocycline
What’s the natural history of lumbar disc herniation?
1/3rd recover at 2 weeks
75% at 3 months
(Vroomen Dutch population study)
What’s the hardy classification?
pituitary adenoma
What is normal vs serviceable hearing?
normal is 20 decibels, 50 decibels is cut off for serviceable
[=right ear, bone conduction
How does 5-ALA work?
5-ALA is absorbed by lots of cells and converted to fluorescent protopophyrin IX. HGG are unable to absorb this.
Draw a neuronal action potential depolarising?
Starts -70mV -
Depolarises to +40mV - influx of sodium
Repolarises to -90mv with refractory period - (voltage gated potassium channels)
What are settings for 5-ALA and ICG?
For 5-ALA use a light source at 400nm and for ICG digital camera sensitive at 800nm
What’s incidence of crouzon
1:65,000
What are the craniosynostosis syndromes, genes, key features?
Crouzon - midface hypoplasia, FGFR2 or FGFR3
Pfeiffer - broad short thumbs or big goes FGFR 1 FGFR 2
Apert - FGFR 2 - syndactyly - looked like had glabella pushed in
Also
Saethre-Chotzen - TWIST1
Muenke - coronal synostosis FGFR 3
Describe the papile grading?
Grade 1 - germinal matrix
Grade 2 - intraventricular
Grade 3 - intraventricular + hydro
Grade 4 - intraventricular + intraparenchymal
What’s the ventricular index treatment line?
97th centile+4
What weight for VPS?
2kg
Draw the brachial plexus
5 roots
Upper Middle Inferior Trunks
Each gives ant and post division
Posterior divisisons form posterio cord
Lateral cord from upper two
Medial cord from lower two
How much radiotherapy in Stupp protocol?
60Gy in 30 fractions
What is chance of AVM obliteration with gamma knife?
75% at 4 years
What are hounsfield units for air, water, blood, calcium?
Hounsfield units - water=0 air=-1000. Blood=50-70 hounsfield units, calcium>150
What are the RANO (response assessment in neuro-oncology) criteria?
Complete Response (CR) - disappearance of all enhancing disease, clinically stable or improved
Partial Response (PR) - 50% decrease in measureable enhancing disease, clinically stable
Progression - 25% increase in enhancing lesions or any new lesions with clinical deterioration
Stable - None of the above
How would you distinguish true tumour progression from pseudoprogression?
MRS
What are the borders of Kambin’s triangle?
NB - variable description of this
Medially - superior articular process/inferior facet
Inferiorly - transverse process
Superiorolaterally - nerve root
What evidence to you know for early decompression in spinal cord injury?
STASCIS study compares 6 month outcome for cervical SCI with early and late surgery. 3x chance of 2 grade improvement with early surgery.
How do you assess for craniocervical dissociation?
Powers ratio < 1
(Basion–>posterior C1) / (opisthion–>ant C1)
Where do spinal cord schwannomas typically occur?
Posterolateral (sensory root) in obsteinerredlich zone
What is differential for primary bony tumours of spine?
What primary bone tumours of spine could occcur?
Osteogenic - e.g. osteoblastoma, osteosarcoma
Chondrogenic - e.g. osteochondroma, chondrosarcoma
Vascular e.g hamangioma (?ABC)
Haemotopoeetic e.g myeloma, lymphoma, histiocystosis
Notochordal - chordoma
What are the boundaries of kawases triangle?
Manbidular division one side
GSPN other side
Back is line between geniculate ganglion and V3 drawn along petrous apex
What is the grading for Moya Moya?
Angiographic stages (Suzuki grade)
- Stenosis of distal intracranial ICAs
- Formation of moyamoya collateral vessels at the base of the brain
- Further prominence of moyamoya vessels as stenosis of the anterior circulation progresses
- Severe stenosis or occlusion of the entire circle of willis
- Enlgagement of extracranial collateral vessels
- Occlusion of distal ICAs, disappearance of basal moya moya vessels and cerebral vasculariation from extracranial sources only
Describe the neuronal migration abnormalities?
Lissencephaly - maldevelopment of cerebral convolusions. Agyria (completely flat), pachygyria, polymicrogyria (small gyri)
Schizencephaly - grey matter lined cleft (distinguishing it from porencephaly) between surface and ventricle. Open lipped or closed lipped (walls fused)
Heterotopia - abnormal grey matter (anywhere from subcortical grey matter to the subependymal lining of the ventricles
Focal cortical dysplasia - local migratiln failure
When does infantile germinal matrix persist until?
35 weeks
Haemorrhage typically 32 weeks or earlier
Things to warn the surgeon about in SSEP/MEP
SSEP - 50% decrease in peak signal amplitude from baseline
Increase in peak latency >10%
Complete loss of a waveform
TCMEP - sustained 50% decrease in signal amplitude
DEP - decrease in signal of > 60%
Intevention for SSEP/MEP changes (Vitale checklist)
- Verify change in real (rule out interference from other equipment - OR table, C-arm, microscope…anything with. a plug). Check connections. Verify that stimulating electrodes and recording leads are making good contact.
- Place OR on alert status
Announce intraoperative pause and stop the case. Eliminate possible distractions. Inform anaesthetist, experienced colleague in
- Anaeshtic metabolic - optimise MAP, check haematocrit, optimize blood pH, normalise patient body temperature, check anaesthetic technical factors, consider Stagnara wake up test
- Surgical considerations - visually check position, remove traction if used, decrease distraction or other corretive forces, remove rods, remove screw that could correlate with change and re-probe for breach, check for spinal cord compression, check for nerve root compression at osteotomy sites, obtain intraoperative imaging (CT or O-arm if available), consider staging operation if practical
- Stagnara (if feasible) - lighten anaesthetic and ask patient to wiggle toes
- Consider IV steroids
What windows are there for TCDs?
Almost all TCD is via the transtemporal window (MCA, ACA, PCA, terminal ICA)
[otherwindows exist - transorbital (ophthalmic), occipital (verts and basilar), submandibular (distal extracranial ICA)]
Lindegard ratio >3 is pathological (ratio ICA to MCA)
Where are EEG leads?
10:20 rule
Odd left, Even right
FP - frontopolaer
F - frontal
C - coronal
P - Parietal
O - occipital
T.- temporal
A - auricular
What are contradindications to MEPs?
History of epilepsy/seizures
Past surgical skull defects
Metal in head or neck
Special care with implanted electronic devices
What was result of cooling?
Cooling in eurotherm trial (2nd line after sedation) 32-35 degrees was harmful
What dose TXA is recommended in CRASH-3?
1g over 10min then 1g over 8 hour
Whats the size of a cranial perforator?
14mm and 11mm
What are brain trauma foundation indications for ICP monitoring?
GCS 3-8 + abnormal head scan
OR GCS 3-8 with normal scan if age >40, unilateral or bilateral motor posturing, of SBP <90mmHg
What is brain trauma foundation target ICP?
ICP <23
What are the relevant tumour volumes in radiotherapy planning?
GTV - gross tumour volume (enhancing in GBM, flair in LGG)
Clinical target volume
Planning target volume (accounts for terrors)
Describe biochemical differences between SIADH and CSW?
Both low sodium
Both low serum osmolality (normal 285-295)
Both Urine osmolality > plasma osmo
Both relatively elevated urine sodium (>50 CSW, 20-40 SIADH)
Treatment CSW - fluid replacement and salt replacement, no diuretics, fludrocortisone
What are ligaments of occipitocervical junction?
C1 to occiput
C2 to occiput
C2 to atlas
C1 to occiput - anterior alanto-occipital membrane, posterior atlanto-occipital membrane, ascending band of cruciate ligament
C2 to occiput - tectorial membrane, alar ligaments, apical ligament (occipoalar)
C2 to atlas C1 - transverse ligament, descending band of cruciate ligament, apical ligament (atlanto-alar)
Describe the engel classification
1 - seizure free
2 - rare seizures
3 - substanital improvement
4 - no improvement
What are safe doses of local anaesthetic?
Lignocaine 3mg/kg
7mg/kg with adrenaline
Bupivacaine 2mg/kg
Local anaesthetic toxicity?
Coma
Seizures
Hypotension
AV block
What’s MAC 1?
Mean alveolar concentration
Level required to prevent motor response to pain in 50% of subjects
What’s the blood supply of the optic chiasm?
Superior hypophyseal and perforators
How do ICP monitors work?
Strain gauge - Transistor that changes resistance depending upon pressure it’s under
Fibreoptic - using mirror with deformation
Which way do you look in seizure related to frontal eye fields?
Away from seizure focus
What are borders of Kambin’s triangle?
Root superolaterally
Endplate inferiorly
Theca medially
What drugs would you give for TN?
Carbamzepine 100mg BD (increasing to 400mg TDS if required)
Oxycarbazepine
Baclofen
Gabapentin
Phenytoin
Amitryptaline
Lamotrigine
How do you interpret lumbar infusion studies
Infuse until you reach plateau
Resistance to outflow = (pressure divided by flow in steady state)
If resistance to outflow is >18cmH20/ml/min then this predicts shunt responsiveness
Describe MRS score?
0 - no symptoms
1 - no significant
2 slight disability
3 moderate - can walk
4 modereate severe disability - can’t walk
5 severe disability (bedridden
6 - death
Describe extended GOS
8 components
Dead/vegetative
Severe upper/lower
Moderate upper/lower
Good recovery upper/lower
Where would you place a Paine’s point EVD?
2.5cm superior to anterior fossa floor, 2.5cm anterior to sylvian fissure
SG in D.I.
<1.005
