Neurosurgery (Chapter 8)

Front 1

What lies just in front and just behind the central sulcus (sulcus of Rolando)?

Back 1

• in front lies the primary motor strip
• behind lies the primary sensory strip

Front 2

What portions of the brain are contained in the supratentorial and infratentorial space?

Back 2

• supratentorial space is occupied by both cerebral hemispheres
• infratentorial compartment contains the brain stem and cerebellum

Front 3

What is the opening at the base of the skull that allows the brain stem to connect to the spinal cord?

Back 3

formamen magnum

Front 4

Which cranial nerves arise from the midbrain, pons, and medulla?

Back 4

• Midbrain: CN III, IV
• Pons: CN V, VI, VII, VIII
• Medulla: IX, X, XI, XII

Front 5

What are the major terminal branches of the external carotid artery?

Back 5

• superfical temporal artery (just in front of the ear)
• occipital artery (just behind the ear)

Front 6

Which arteries supplies the largest volume of blood flow to the brain is the most common distribution to receive a vascular embolus?

Back 6

middle cerebral artery

Front 7

What is the role of CSF?

Back 7

• provides structure and cushion
• helps maintain and regulate cerebral and systemic homeostasis

Front 8

CSF from the lateral ventricles drains to the 3rd ventricle through which structure?

Back 8

foramen of Monroe

Front 9

CSF drains from the 3rd to 4th ventricle through which structure?

Back 9

aqueduct of Sylvius

Front 10

What are the structures that allow CSF to exit the ventricular system?

Back 10

• a single medial foramen of Magendie
OR
• laterally via two framina of Luschka

Front 11

Name and describe the various types of cerebral herniations

Back 11

• Transtentorial: tissue moving downward from the supratentorial space through the tentorial incisura into the infratentorial space

• tonsillar: tissue moving from the posterior fossa through the foramen magnum

• subfalcine: tissue moving from one side of the supratentorial space to the other under the falx cerebri

• upward central: tissue moving upward from the infratentorial space through the tentorial incisura into the supratentorial space

• herniation of tissue outside the skull through a craniotomy or traumatic skull defect

Front 12

What are the 5 components of the neurologic examination?

Back 12

• mental status
• cranial nerves
• cerebellar function
• motor & reflex function
• sensory function

Front 13

Corneal reflex evaluates which cranial nerve?

Back 13

trigeminal (CN V)

Front 14

How do you rate reflexes during physical exam?

Back 14

scale from 0-4
• O: absent reflex
• 1: weak reflex
• 2: normal reflex
• 3: overly active reflex with up to 1-3 beats of clonus
• 4: reflex associated with more sustained clonus

Front 15

What is the Hoffman response?

Back 15

finger flexion response with sudden flexion of the distal interphalangeal joint

Front 16

What is the most common CNS herniation syndrome?

Back 16

transtentorial herniation

Front 17

What are some physical manifestations of transtentorial herniation?

Back 17

• dilated pupil on the the same side of the lesion (due to downward pressure on the CN III)
• contralateral hemiparesis (due to pressure on the cerebral peduncles)
• unconsciousness (due to pressure and torsion on the midbrain & reticular-activating system)

Front 18

What are some clinical manifestations of central downward herniation (tonsillar herniation)?

Back 18

• loss of consciousness
• bradycardia and hypertension (Cushing's reflex) & Cheyne-Stokes respirations due to medullary cardiorespiratory dysfunction

Front 19

What are physical manifestations of a subfalcine herniation?

Back 19

• the cingulated gyrus moves underneath the falx cerebri over the corpus callosum putting pressure on the anterior cerebral artery

• causes contralateral lower-extremity monoparesis

Front 20

What is the most common cause of diabetes insipdus?

Back 20

iatrogenic disruption of the hypothalamus or pituitary stalk after surgery for hypothalamic or pituitary tumors

Front 21

At what spinal vertebrae are lumbar punctures often performed?

Back 21

L4-L5 or L5-S1

Front 22

What are the diagnostic study of choice of neurosurgical emergencies?

Back 22

CT scan

Front 23

What are the diagnostic procedure of choice for neurooncology and stroke neurology?

Back 23

MRI scan

Front 24

What are different options for medical treatment of increased intracranial pressure?

Back 24

• elevation of head
• hyperventilation (PCO2 30-35 mm)
• maintain normal volume
• osmotic diuretics (mannitol)
• renal diuretics (Lasix)

Front 25

Why is hyperventilation used only on a temporary basis in an acute herniation?

Back 25

can potentially cause ischemia to an already injured brain

Front 26

What are two ways to monitor intracranial pressure?

Back 26

• ventriculostomy
• intraparenchymal fiberoptic pressure probe

Front 27

Which is the preferred method of monitoring ICP?

Back 27

ventriculostomy because it is therapeutic at the same time that it provides the necessary ICP data

Front 28

What does a ventriculostomy consist of?

Back 28

• a percutaneous Silastic tibe inserted through a burr hole in the skull that courses through brain tissue to the lateral ventricle
• provides a continous column of fluid from the ventricular CSF to an external drainage system

Front 29

Why should neuronal metabolic demands be minimized in patients with head injury?

Back 29

• high metabolic demand could lead to supply-demand mismatch of nutrients
• can cause potential neuronly injury in the setting of decreased cerebral blood flow
• phenytoin (by preventing seizures) and barbituate comas can reduce neuronal metabolic demand

Front 30

What is a concussion?

Back 30

• a clinical syndrome of temporary global brain dysfunction
• can be inferred from a history of brief loss or period of anterograde or retrograde amnesia

Front 31

When do closed crainal vault fractures require surgical exploation?

Back 31

• depression is greater than the crosssectional width of the skull
• occurs in a cosmetically obvious area (ex. forehead)
• associated with an underlying mass lesion that needs to be excised
• associated with an area of intracranial air suggesting dural penetration

Front 32

What are diastatic fractures?

Back 32

fractures with a gap between the fracture edges

Front 33

Subdural hematomas are common in which patients?

Back 33

• elderly patients: have an accentuated distance between their brain and dura due to cerebral atrophy
• patients taking anticoagulant medications

Front 34

When does a subdural hematoma not require surgical evacuation?

Back 34

• when the hematoma is small (< 30 mL volume) and the patient is doing well clinically
• can be treated conservatively with careful follow-up, neurologic examination, and serial CT scanning

* majority of subdural hematomas will naturally resorb

Front 35

What is carotid-cavernous fistula?

Back 35

• when arterial blood epmties directly into the cavernous sinus venous spaces

• can be caused by interal carotid artery damage in the cavernous sinus

• can cause injection & chemosis of the conjunctiva, pulsating exophthalmos w/ a bruit, elevated intraocular pressure from venous congestion, and cranial nerve dysfunction

Front 36

What are the two types of incracerebral hemorrhage?

Back 36

• spontaneous intraparenchymal hemorrhage
• subarachnoid hemorrhage

Front 37

Most TIAs result from either artery-to-artery emboli or cardiac origin emboli. What is the most common source of artery-to-artery emboli?

Back 37

athersclerotic plaque at the carotid bufurcation

Front 38

What are causes of intraparenchymal hemorrhage?

Back 38

• amyloid angiopathy
• AVM rupture
• cerebral infection
• coagulopathy
• drug abuse
• hemorrhage into a brain tumor
• hypertensive arteriolar disease
• vasculitis

Front 39

What are characteristics of amyloid angiopathy?

Back 39

• fragile cerebral arteries due to amyloid protein deposition in the vessel wall
• tend to be subcortical and lobar in location
• most commonly occurs in the parietal lobe (at the parietal-occipital junction)

Front 40

What are potential curative treatment options for AVMs?

Back 40

• high dose radiation (stereotactic radiosurgery)
• microsurgical excision
• endovascular embolization (rare)

Front 41

Name the 2 types of cerebral edema

Back 41

• Vasogenic edema
• Cytotoxic edema

Front 42

Describe vasogenic edema

Back 42

• occurs from an impaired function of the blood-brain barrier
• water and protein are transferred from the vasculature to the interstitial space
• manifests as focal neurologic deficits, disturbances in consciousness, & severe intracranial hypertension

Front 43

Describe cytotoxic edema

Back 43

• involves the actual swelling of brain cells due to increased intracellular fluid
• can be caused by hypoosmotic states, impairment of Na+/K+ pump

Front 44

What is the most common histiology of metastatic brain tumor to present with a single lesion? with multiple lesions?

Back 44

• single cell » renal cell carcinoma
• multiple cell » melanoma

Front 45

What is the most common cranial nerve schwannoma?

Back 45

vestibular schwannomas

Front 46

Bilateral verstibular schwannomas are diagnostic for what genetic disease?

Back 46

neurofibromatosis (type 2)

Front 47

How do patients with vestibular schwannomas present initially and present as the tumor grows?

Back 47

• patient usually has a history of unilateral tinnitus with vertigo that disappears as the vestibular nerve is destroyed
• tumor grows and puts pressure on the auditory nerve causing deafness
• can eventually involve the CN V causing facial numbness and loss of corneal reflex
• ultimately can cause cerebelar deficits and CN IX and X deficits

Front 48

What are different ways to classify pituitary adenomas?

Back 48

• functional (secretes hormones) vs. nonsecretory
• microadenomas (< 1 cm diameter) vs. macroadenomas (> 1cm diameter)

Front 49

What are treatment options for secretory pituitary tumors?

Back 49

• treat medically
- bromocriptine for prolactinoma
- somatastain for acromegaly
- ketoconazole for Cushing's disease

• treat surgically
- microsurgery
- endoscopoic trans-sphenoidal surgery

Front 50

What is the most common pediatric brain during during the first 9 years? between ages 9-19?

Back 50

• medulloblastoma is the most common tumor during the first 9 years
• pilocytic astrocytoma is the msot common from ages 9-19

Front 51

What are some sources of cerebral abscesses?

Back 51

• cardiac source (valvular or congenital heart disease)
• dental infection
• head trauma
• mastoiditis
• previous surgery
• sinusitis

Front 52

What are the classic symptoms of a brain abscess?

Back 52

• headache (most common ~ 70%)
• fever (less than 50%)
• focal neurologic deficits

* this triad is found in fewer than 50% of patients

Front 53

What does a brain abscess look like on CT or MRI?

Back 53

a uniform thin, enhancing wall surrounding a low-density core

Front 54

What complication can lumbar puncture cause in patients with a mass lesion?

Back 54

it decreases the pressure beneath a mass lesion and encourages transtentorial herniation

Front 55

What is the treatment of choice for brain abscess?

Back 55

stereotactic aspiration

Front 56

What are the most common causes for viral encephalitis?

Back 56

• primary HIV CNS infection
• primary CNS repetic encephalitis
• rabies

Front 57

What is Klüver-Bucy syndrome?

Back 57

• herpetic encephalitis characterized by bilateral temporal lobe involvement
• can lead to dramatic limbic system and behavioral symptoms

Front 58

What are organisms commonly involves in fungal CNS infections?

Back 58

• Actinomyces
• Aspergillus
• Blastomyces
• Candida
• Coccidioides
• Cryptococcus
• Histoplasma
• Mucormuces
• Nocardia

Front 59

Which fungal infection is know for producing hemorrhagic encephalitis and areas of hemorrhagic infarction?

Back 59

asergillosis

Front 60

Which fungus produces a devastating, rapidly progressive, and usually fatal disease and involves the CNS by direct extention of sinus disease in patients with diabetes and poorly controlled blood sugar?

Back 60

Mucormyces (ie. Mucormycosis)

Front 61

List some parsitic infections of the CNS

Back 61

• cysticercosis (acquired from eating poorly cooked, infested pork)
• echinococcosis (endemic in sheep-raising communities)
• toxoplasmosis (associated with HIV/AIDS)

Front 62

What is a Collier's sign?

Back 62

• aka sunset sign
• tonic conjugate downgaze caused by CN III interference from hydrocephalus

Front 63

What are encephaloceles?

Back 63

• herniations of malformed brain through defects in the skull
• most common are occipital and cerebellar emcephaloceles

Front 64

List examples of primary epilepsy surgeries

Back 64

• cortical ressections
• functional hemispherectomy
• partial corpus callosotomy
• standard temporal lobectomy
• selective amygdalohippocampectomy
• subcortical disconnections

Front 65

What is HFS and what is its surgical treatment?

Back 65

• hemifacial spasm is a progressive disorder of the facial nerve that leads to unilateral rhythmic facial twitching of the facial musculature

• surgical treament: posterior fossa cerebellopontine angle exploration with microvascular decompression of the centrally myelinated portion of the facial nerve

Front 66

What are surgical treatment options for Parkinson's disease once medical treatment has become refractory?

Back 66

• stereotactic lesioning of select areas of the globus pallidus (pallidotomy)
• stereotactic lesioning of select areas of the thalamus (thalamotomy)
• selective thalamic stimulation after stereotactic insertion of stimulator electrodes

Front 67

What is normal pressure hydrocephalus?

Back 67

• a clinical condition in which there is symmetric ventricular enlargement on CT or MR scan with normal iCP
• associated with a triad of symptoms (gait disturbance, incontinence, and dementia)
• improves or resolves with CSF diversion by VP shunting

Front 68

Normal pressure hydrocephalus must be distinguished from what condition to avoid complications such as subdural hygromas and hematomas?

Back 68

• ex vacuo ventriculomeagly resulting from gradual brain loss
• can be caused by multiple ischemic insults, previous traumatic injuries, primary neurodegernerative disorders)

Front 69

What is currently the gold standard for assessing patients for normal pressure hydrocephalus?

Back 69

• placement of a lumbar drain and setting it to withdraw CSF at VP shunt rates
• meanwhile, the patient is evaluated for gait by a physical therapist and cognitive function by a speech therapist

Front 70

Which vertebrae are lordotic?

Back 70

cervical and lumbar vertebrae

Front 71

Which vertebrae are kyphotic?

Back 71

thoracic and sacral vertebrae

Front 72

The lemniscal sensory pathway is located in which portion of the spinal column and provide awareness of which sensations?

Back 72

• runs dorsally in the dorsal columns
• provides vibration and joint position sense

Front 73

Where are the pyramidal tracts located in the spinal column?

Back 73

laterally

Front 74

Where are the spinothalamic tracts located and what sensations does it relay?

Back 74

• run anterolaterally on either side
• conveys pain and temperature sense

Front 75

What is anterior spinal cord syndrome?

Back 75

• leads to bilateral dysfunction of the spinothalamic pathways and pyramidal tracts with sparing of the lemniscal pathways

• leads to upper motor neuron findings and pinnsensation reduction or loss bilaterally below the level of the lesion

• spares joint vibration and position sense bilaterally

Front 76

What is posterior spinal cord syndrome?

Back 76

• leads to bilateral dysfunction of the lemniscal sensory pathways and pyramidal tracts

• spares the spinothalamic pathwyas

• leads to upper motor neuron finds and vibration and joint position sense reduction or loss bilaterally below the level of the lesion with sparing of pin sharpness appreciation bilaterally

Front 77

What is Brown-Sequard Syndrome?

Back 77

• aka lateral spinal cord syndrome

• leads to unilateral dysfunction of the lemniscal and spinothalmic sensory pathways as well as the ipsilateral pyramidal tract

• leads to ipsilaterael vibration and proprioception loss and contralateral loss of pain sensation below the level of the lesion

Front 78

What is a Jefferson fracture?

Back 78

• an axial load and compression fracture of the anterior and posterior arches of C1
• open-mouth c-spine views shows lateral spreading of the lateral masses of C1

Front 79

Describe the 3 types of odontoid fractures

Back 79

• Type 1: avulsion fractures of the odontoid tip
• Type 2: fractures occur right at the base of the odontoid
• Type 3: fracture goes down into the base of the body of C2

Front 80

Describe a Hangman's fracture

Back 80

• a bilateral pedicle fracture of C2
• usually from acute hyperextension injury

Front 81

What is the most common mid-thoracic traumatic fracture?

Back 81

vertebral body compression fracture

Front 82

What are potential sequelae of spinal cord injry?

Back 82

• decubitus ulcers
• DVTs
• pneumonia
• pulmonary emboli
• septicemia
• urinary infection
• urinary reflux

Front 83

What are examples of degenerative diseases of the spine?

Back 83

• disc herniation
• spinal osteoarthritis & stenosis
• spondylolisthesis

Front 84

What causes degeneration of the intervertebral disc?

Back 84

• the nucleus pulposus becomes desiccated due to age or recurrent trauma
• detected as a "black disc" on T2-weighted MRI

Front 85

What is the treatment for disc herniation?

Back 85

• conservative treatment:
- rest
- analgesics
- anti-inflammatory agents
- muscle relaxants

• surgical treatment:
- microscopic or endoscopic excision

Front 86

What are causes of lumbar stenosis?

Back 86

• progressive encroachment of the spinal canal from the ventral aspect (ex. disc degeneration, disc bulge, and reactive osteophyte formation

• from the posterior lateral direction (ex. facetal hypetrophy and arthropathy)

Front 87

What are examples of vascular spine disease?

Back 87

• AVMs
• dural A-V fistula
• epidural hematomas
• ischemic infarctions

Front 88

What are some causes of spinal cord stroke?

Back 88

• embolic occlusion of the anterior spinal artery
• flow-related ischemia due to significant systemic hypotension
• loss of a major segmental feeding artery (ex. artery of Adamkiewicz)

Front 89

At what vertebral level is the spinal cord most susceptible to flow-related ischemia?

Back 89

T4-T5 level

Front 90

Name and describe the 3 groups of spinal tumors

Back 90

• extradural tumors: arise from the osseous element of the spinal column

• intradural extramedullary tumors: arise from the dural shealth around the spinal cord OR from the Schwann cell sheath around the spinal roots

• Intramedullary tumors: arise from the glial element of the spinal cord OR from trapped ectodermal elements

Front 91

What is the most common spinal tumor?

Back 91

extradural tumors (usually metastatic)

Front 92

What is the treatment for spinal cord compression from a metastatic tumor?

Back 92

• immediate: high-dose IV steroids

• radiotherapy (if the patient is in good shape and the tumor is radiosensitive)

• surgical decompression (reserved for evidence of neurological deterioration)

Front 93

What are examples of primary spine tumors?

Back 93

• intradural extramedullary tumors
• intradural intramedullary tumors

Front 94

What is the most common intradural extramedullary tumor?

Back 94

• neurofibromas

* multiple tumors are found in patients with neurofibromatosis

Front 95

What is a myxopapillary ependymoma?

Back 95

• a benign ependymoma that is prone to develop in the filum terminale within the cauda equina

* the filum terminale within the cauda equina contains a continuation of the ependymal lining of the central spinal canal

Front 96

What is the most common intramedullary tumor in adults?

Back 96

ependymoma

Front 97

What type of spinal cord tumor is assoicated with von Hippel-Lindau syndrome?

Back 97

hemangioblastomas

* Von Hippel-Lindau disease (VHL) is a rare inherited genetic condition involving the abnormal growth of tumors in parts of the body which are particularly rich in blood supply

Front 98

What are examples of infections of the spine?

Back 98

• discitis
• epidural abscess
• osteomyelitis

Front 99

What is the most common cause of fungal osteomyelitis?

Back 99

coccidioidomycosis

Front 100

What is spina bifida?

Back 100

• inadequate closure of the neural tube, vertebral column, and overlying soft tissues
• usually lumbar or lumbosacral
• most common form is spina bifida occulta

Front 101

What is the difference between meningocele and myelomeningocele?

Back 101

• Meningocele: occurs when most of the elements dorsal to the spinal canal do not close; does not cause neural malformation

• Myelomeningocele: when neural tube closure is incomplete and malformed neural elements protrude posteriorly through a defect in the dura and vertebral lamina

Front 102

What are some specific pain syndromes that can be successfully treatment with neurosurgery?

Back 102

• Trigeminal neuralgia
• Glossopharyngeal neuralgagia

Front 103

What is the treatment of trigeminal neuralagia?

Back 103

• intially: anticonvulsant meds (ex. Carbamazepine, Oxcarbazepine)
• microvascular decompression of the trigeminal nerve