SANS Questions Flashcards
Third Ventricle anatomy from ETV view.
Name each structure
- Fornix
- anterior commissure
- lamina terminalis
- -
- chiasmatic recess
- optic chiasm
- infundibular recess
- tuber cinerium: where ETV is made, connects interpeduncular and prepontine cisterns
- mamillary bodies
Name the following structures.
Where is the cochlear nerve
- superior vestibular area> superior and lateral semicircular canals
- inferior vestibular area> posterior semicircular canal
- vertical crest, Bill’s bar
- transverse crest
- cochlear nerve, filaments perforate lamina crimosa, direct strokes medial to lateral to preserve nerve; located anterior to inferior vestibular area
- facial canal
What landmark is used to delineate the lateral extent of removal of occipital condyle?
The anterior condylar vein
Indicates that 1/3 of occipital condyle has been removed
More removal would result in atlanto-occipital instability
Where is brocas area?
Pars opercularis
in inferior precentral sulcus
Histopathologic characteristic of central neurocytoma
Fried egg appearance similar to oligodendroglioma
uniform and round cells
(Rosenthal fibers are characterist of JPA)
Subependymoma
middle aged/elderly adults
usu in inf 4th ventricle
hypocellular, prominent fibrillary background
What genetic abnormalities are associated with each of these tumors
- oligodendrogliomas
- astrocytoma (gemistocytic/fibrillary) and mixed oligoastrocytomas, secondary GBM
- GBM
- neurofibroma
- ganglioglioma/papillary craniopharyngioma
- cavernous malformation
- meningioma
- 1p19q deletion/LOH
- TP53 gene mutation
- EGFR amplification, LOH 10q, P16 deletion, PTEN mutation
- NF1 mutation
- BRAF mutation>ERK/MAPK
- MEKK3 increased in endothelial cells>KLF 2/4
- AKT1, SMO
Adjuvant postop therapy for GBM
chemotherapy (tamozolamide)
Fractionated External beam rad tx at 60 Gy
DIPG (diffuse pontine glioma) treatment
Favorable prognostic indicators
conformal radiotherapy
age less than 4, smaller tumor size, low grade histology
Which ventricular areas are deep to these gyri
- inferior frontal gyrus
- supramarginal gyrus
- middle temporal gyrus
- middle frontal gyrus
- frontal horn
- atrium
- temporal horn
- frontal horn
What imaging modality/sequences can differentiate cholesteatomas from encephalocele in case of tegmen defect?
T2 and DWI
T2 can identify brain matter
Cholesteatomas can be hyperintense on T2
Cholesteatomas diffusion restrict
When can SRS be used for metastatic intracranial disease?
Up to 5 mets <3 cm in size
WBRT for leptomeningeal disease
What chemotherapy increases risk for radiation necrosis?
Immunotherapy
PD1 inhibitors that inhibit checkpoints in tumor cells that suppress the immune system>better immune surveillance but also increases risk of radiation necrosis (immune mediated process) two-fold
Glucocorticoids/anti-VEGF agents decrease immune response and are mainstays of treatment for rad necrosis
Persistent trigeminal artery
connection between cavernous sinus and basilar artery below SCA
Branches of the meningohypophyseal trunk
Comes off the cavernous segment
- inferior hypophyseal arteries
- dorsal meningeal artery
- tentorial arteries
MR spectroscopy
- NAA
- choline
- creatine
- glutamine/glutamate
- mioinositol
- lactate and lipids
- neuronal viability
- involved in synthesis of phospholipids> marker of cellular turnover (high in gliomas)
- marker or internal reference
- astrocyte marker (may be altered in setting of neuronal damage)
- astrocyte marker elevated in Alzheimer’s disease
- Elevated in inflammatory process, infection, and necrosis
Hemangiopericytoma
CNS tumor that invades locally and can metastasize to lungs, liver and bone
uniformly cellular tumor similar to fibrous tumor with ectatic compressed thin walled branching vessels with gaping sinusoidal spaces (staghorn configuration)
most common suprasellar squamous tumor in an older adult
craniopharyngioma
adamantinomatous form is more common
papillary form when it occurs usually occurs in older adults (peak 40-50 yo)
solid sheets of squamous epithelium with pseudopapillary formations
lack wet keratin and palisading cells and frequently calcifications of adamantinomatous subtype
most common pineal tumor in adults esp females
pineocytoma
(germ cell tumors, more likely in children and males)
What tumor is often synchronously found in the suprasellar and pineal regions?
germinoma
high bHCG, nl AFP
highly sensitive to radiation
can have endocrine disturbance (suprasellar involvement)
DDX of mixed solid and cystic suprasellar tumors in children
- Craniopharyngioma (adamantinomatous most likely)
- Rathke’s cleft cyst
- Langerhaan’s histiocytosis
- germ cell tumors (germinoma, teratoma)
- astrocytoma
- pituitary adenoma
Treatment of esthesioneuroblastoma
If no mets, surgical resection followed by conformal radiation therapy
If mets are present, add chemotherapy
Addisonian crisis
hyponatremia, hypoglycemia, HYPERkalemia, fatigue, high fever, hypotension, AMS> give glucocorticoids
Histopathology of schwannoma
Antoni A (highly cellular areas), Antoni B (cystic low cellular areas)
Verocay bodies: groups of pallisading nuclei around an eiosinophilic core
Vascular supply of the SC
- Artery of Adamkiwitz- anterior supply T8-L2, located on the left most often
- lateral arteries supply lat and posterior regions
- Posterior supply dorsal columns
- median sacral artery supplies the sacral canal
What kind of 3rd nerve palsy would a PCOM aneurysm most likely lead to first?
midriasis by preferentially affecting parasympathetic fibers on the outside of the nerve
DM leads to a pupil sparing 3rd nerve palsy preferentially since glycosilation of vessels affect the inner part of the nerve
What is this caused by?
GRE showing cortical and subcortical microhemorrhages/lobar hemorrhage> amyloid microhemorrhages
CHADS score and blood thinner relationship
CHADS
- CHF
- HTN
- Age older than 75
- DM
- S2 previous stroke or TIA (2 points)
If 0-1: ASA
If 2 or more> CMD
Definition of an infundibulum
- less than 3 mm
- vessel of origin is found on the apex
- PCA
- triangular in shape
What pathologies have an early draining vein
AVM
VOGM
AVF
Spetzler Martin Grade
The Spetzler-Martin grade was originally validated in a study of 100 consecutive patients treated with microsurgical excision of AVMs. Morbidity rates were as follows:
• Grade 1: 0%
• Grade 2: 5% minor deficit, 0% major deficit
• Grade 3: 12% minor deficit, 4% major deficit
• Grade 4: 20% minor deficit, 7% major deficit
• Grade 5: 19% minor deficit, 12% major deficit
What is this?
venous angioma
caput medusae, sunburst appearance
variation of normal venous drainage characterized by a tuft of medullary veins that converge into a large central trunk that drains either to the deep or superficial venous system
Intracranial venous drainage
Antiplatelet drugs
Spinothalamic tract
Corticospinal tract
Medial lemniscal pathway
What structure runs lateral to the lumbar spine and medial to the IP?
Sympathetic trunk
(Ilioinginal nerve emerges upper lateral border of the IP and innervates quadratus lumborum)
Atlanto-occipital dislocation definitive treatment
Instrumentation
Patients can have lower cranial nerve palsy, hemiplegia or quadriplegia
Traction is contraindicated>10 percent risk of neurologic injury
What type of injury is this?
Jefferson Fracture
C1 axial loading fracture
mechanical stability is dependent on the transverse ligament
Rule of spence: If the sum of the overhang of the lateral masses of C1-2 is greater or equal to 7> transverse ligament is thought to be disrupted
ASIA scale
TLICS score
TLICS = thoracolumbar injury Classification and severity
PLC = posterior ligamentous complex
AO spine classification
Pelvic parameters
Lumbar radicular pain
What type of craniosynostosis is this?
Metopic synostosis also known as Trigonocephaly is caused by premature fusion of the metopic suture
thought to result from abnormal signaling in growth factors including transforming growth factor (TGF) and fibroblast growth factor (FGF).
Unicoronal synostosis is characterized by flattening of the forehead on the affected side with contralateral bossing which is not present in this CT. This along with the foreshortening of the orbit and zygoma produces the harlequin eye. Sagittal synostosis is also a straightforward diagnosis where the CTshows the characteristic long-boat shaped head along with narrowing of the biparietal diameter. For lambdoid synostosis, the ipsilateral tragus and petrous bone are drawn posteriorly and the midline of the foramen magnum is drawn to the affected side. Bicoronal synostosis is characterized by a very broad and tall forehead from the premature fusion of both sutures with characteristic CT findings.
When should this newborn undergo cranial vault reconstruction?
This child has a clover-leaf skull or Kleeblattschadel deformity. This may be seen in association with Pfeiffer’s syndrome and other types of syndromic craniosynostosis. This pan-synostosis causes severe restriction of calvarial growth and intracranial hypertension in the neonatal period. Very early decompression in infancy, often with staged reconstruction is generally recommended. There is a high incidence of neurological disability even among survivors. The patient pictured in this question underwent a decompressive and reconstructive procedure at 3 days of age and has required several subsequent cranial remodeling procedures along with tracheostomy and treatment for hydrocephalus. He is cognitively normal.
Hippocampal complex
Brachial plexus
What causes this?
Hand of benediction caused by median nerve damage
flexion of the index finger and partially the long finger at the proximal phalangeal joints (flexor digitorum superficialis), flexion of the distal phalangeal joints of the index and partially the long finger (lateral half of the flexor digitorum profundus), most control of thumb flexion at the metacarpal-phalangeal and interphalangeal joints (flexor pollicis brevis and longus), and flexion of the metacarpal-phalangeal joints of the index and likely the long finger (1st and 2nd lumbricals). Because of this combination of deficits, when the patient attempts to make a fist the first two, and partially the third digit does not flex, demonstrating the classic hand position illustrated in the above figure.
Cordotomy lesioning area
Answer, 4. Cordotomy consists of surgical interruption of the anterolateral spinothalamic tract (4). Knowledge of spinal cord tract organization is paramount for the safe performance of ablative procedures for pain, such as cordotomy. It can be performed either percutaneously at C1, or by an open procedure in the thoracic spinal cord. Care must be taken during this procedure to stay ventral to the dentate ligament, which separates the dorsally located corticospinal tract (3) from the spinothalamic tract. The dorsal root entry zone (2) is the target for DREZ lesioning procedures, and the midline pain pathway (1) is the target for the midline myelotomy for visceral pain. The ventral white decussation (5) contains fibers from both spinothalamic tracts and is the target for commissural myelotomies.
