Neurosurgery: Neoplastic Disease Flashcards
Approach to:
Inferior frontal lobe and parasellar region
Bicoronal incision with unilateral/bilateral subfrontal approach
Pterional approach
Approach to:
Sellar region
Transsphenoidal
Bicoronal incision with unilateral/bilateral subfrontal approach
Pterional approach
Approach to:
Frontal lobe
Frontal craniotomy (linear, curved, or horseshoe incision)
Approach to:
Anterior temporal lobe
Temporal craniotomy (linear incision)
Approach to:
Posterior temporal lobe
Temporal craniotomy (linear, reverse question mark, or Isle of Mann incision)
Approach to:
Parietal lobe
Parietal craniotomy (linear or horseshoe incision)
Approach to:
Occipital lobe
Occipital craniotomy (linear or horseshoe incision)
Approach to:
Trigone of lateral ventricle
Appropriate craniotomy for superior parietal, middle temporal gyrus, lateral tempero-occipital, or transoccipital approach (linear or horseshoe incision)
Approach to:
Anterior third ventricle
Frontal parasagittal craniotomy and interhemispheric/transcallosal or transcortical approach
Interforniceal or transchoroidal approach once within
Approach to:
Posterior third ventricle/pineal region
Suboccipital transtentorial
Supracerebellar infratentorial approach
Interhemispheric transcallosal (splenium) approach
Transcortical parietal approach (rarely used)
Approach to:
Midline posterior fossa/fourth ventricle
Suboccipital craniotomy (linear incision)
Approach to:
Lateral posterior fossa/CPA
Retrosigmoid craniotomy (linear incision)
Approach to:
Upper clivus
Subtemporal approach and anterior petrosectomy (linear or horseshoe approach)
Approach to:
Middle and lower clivus
Combined retrosigmoid posterior temporal craniotomy and posterior petrosectomy (curvilinear incision)
What is located two finger breadths above the zygomatic arch and one thumb’s breadth behind the frontal process of zygomatic bone?
Pterion
What landmark does the asterion represent?
Asterion is on skull over the lower half of the transverse/sigmoid sinus junction
Asterion: junction of lamboid, occipitomastoid, and parietomastoid sutures
What lays at the junction of the lamboid and sagittal suture?
Lambda
What lays at the junction of the coronal and sagittal sutures?
Bregma
Where is the inion located?
At indentation below external occipital protuberance
How can you roughly estimate the location of the Sylvian fissure? (Stepwise approach)
1) Draw a line connecting the nasion and inion, find the 75% point on the line (closer to inion)
2) Mark frontozygomatic point
3) Connect the two points and the Sylvian fissure travels along this axis
- Pterion is located ~3cm behind the frontozygmatic point
How can you approximate location of Rolandic fissure (aka central sulcus)? (Stepwise approach)
1) Find upper Rolandic point (2cm posterior from 50% point on a line connecting nasion and inion)
2) Lower Rolandic point is at junction of line from upper rolandic to midzygomatic arch and sylvian fissure line (Lower Rolandic point is 2.5 cm behind pterion along Sylvian line)
How far behind the coronal suture is the motor stip usually located?
4 to 5.4 cm
What is a rough estimate of the location of the Angular gyrus (which is part of Wernicke’s area)?
Just above pinna of ear
Astrocytic tumors may be graded II, III, or IV. What are these specific types typically called?
Grade II: Low grade astrocytoma
Grade III: Anaplastic astrocytoma
Grade IV: GBM
What is standard treatment for astrocytomas?
Surgical resection (partial or complete) followed by external beam radiation and temozolomide
What are common locations for pilocytic astrocytomas?
Cerebellar
Optic glioma type
Hypothalamic hemisphere
Optic gliomas are common in what genetic condition?
What type of tumors are these typically?
NF1
Pilocytic astrocytomas
What is tx of choice for cerebellar pilocytic astrocytomas?
Surgical resection
They often have an enhancing mural nodule; if the mural nodule (contrast-enhancing) is removed the cyst wall doesn’t need to be completely taken
What is treatment of choice for pilocytic astrocytomas of optic nerve or hypothalamus?
If sparing resection can be completed then removal but if resection risky then biopsy with chemo and radiation
How do oligodendrogliomas often present?
Seizures and/or hemorrhage
What is unique about oligodendrogliomas on CTH?
They may have associated calcifcation
What chromosomal loss is associated with better response to treatment in oligodendroglioma?
Loss of 1p and 19q
Where do ependymomas often arise from?
Floor of 4th ventricle
What is preferred treatment of ependymomas?
Should you aim for full resection?
Surgical resection
Maximal resection is associated with improved survival
Given proximity to CSF space. What adjunctive test should be done in patients with ependymoma?
LP (cytology) and spinal MRI to look for subarachnoid mets
In what age group do choroid plexus papillomas often present? How do they present? What is mgmt?
<2 yo
HCP
Resection followed by chemo (radiation if carcinoma)
What are the different types of pediatric brainstem glioma (3)?
Tectal glioma
Focal tegmental mesencephalic
Diffuse pontine glioma