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Flashcards in NEUROSX Deck (50):
1

Common Neurosurgery Procedures

Drainage Craniotomy Cranioplasty Craniectomy Cerebrovascular surgery

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Possible locations for intracranial hemorrhages

Intraparenchymal Intraventricular Subarachnoid Subdural/epidural

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Intracranial hemorrhage

Intraparenchymal or intraventricular hemorrhage 8-13% of all strokes More likely to result in death or major disability than ischemic stroke or subarachnoid hemorrhage Causes: HTN damage, rupture of aneurysm or AVM, cerebral amyloid angiopathy, intracranial neoplasm, coagulopathy

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Location of hemorrhage: basal ganglia, internal capsule

Classic Sx: contralateral hemiparesis 50% of intracranial hemorrhages

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Location of hemorrhage: Thalamus

Contralateral hemisensory loss 15% of intracranial hemorrhages

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Location of hemorrhage: Cerebral white matter (lobar)

Depends on location (weakness, numbness, partial loss of visual field) 10-20% of intracranial hemorrhages

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Big factor in intracranial hemorrhage

Blood pressure control -Cannot be too high or too low -Permissive HTN: allow BP to be a little higher than normal, but not so high its causing issues

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When to consider surgery in intracranial hemorrhage

-Cerebellar hemorrhage greater than 3 cm -Intracerebral hemorrhage associated with a structural vascular lesion -Young patients with lobar hemorrhage

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Surgical approaches in intracranial hemorrhage

-Craniotomy and clot evacuation under direct visual guidance -Stereotactic aspiration with thrombolytic agents -Endoscopic evacuation

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Subarachnoid hemorrhage (SAH)

Extravasation of blood into the subarachnoid space between pia and arachnoid membranes "worst HA of my life" "Thunderclap HA" Meningismus but no fever Dx: CT, angiogram, LP

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Causes of SAH

Most common: trauma Non-traumatic: ruptured cerebral aneurysm (also AVM)

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Hunt-Hess grading system for SAH

0: asx; unruptured aneurysm 1: Awake; asx or mild HA; mild nuchal rigidity 2: Awake; moderate to severe HA; cranial nerve palsy (e.g., cranial nerve III or IV), nuchal rigidity 3: Lethargic; mild focal neuro deficit 4: Stuporous; significant neuro deficit 5: comatose; posturing *4 and 5 require intubation and hemodynamic monitoring*

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Complications to avoid in SAH

Rebleeding Vasospasm Hydrocephalus Hyponatremia Seizures Pulmonary complications Cardiac complications

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Surgical tx in SAH

Clipping ruptured aneurysm Endovascular treatment (coiling)

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Epidural Hematoma

Arterial bleed from middle meningeal artery; forms a hematoma between inner skull and dura Space-occupying lesion Accumulation can be immediate or delayed

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Sx of epidural hematoma

Lucid interval between initial LOC at time of impact and a delayed decline in mental status HA N/V Seizures Focal neuro deficits

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Epidural hematoma on CT

Convex hematoma associated with parietal skull fracture

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Epidural Hematoma: Tx

Small: conservatively; monitor Definitive tx: surgical evacuation [craniotomy and evacuation of hematoma] Minimally invasive uses burr holes and negative pressure drainage Novel therapeutic approaches: endovascular embolization, thrombolytic evacuation using suction drain

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Subdural Hematoma

More common than epidural hemorrhages-- elderly, children, alcoholics Sudden jarring or rotation of head, blow to head, fall Movement of brain shears and tears small veins Blood accumulates over several hours

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Subdural hematoma on CT

Crescent shaped Hyperdense (may contain hypodense foci due to serum, CSF, or active bleeding) Does not cross dural reflections

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Subdural hematoma: Emergent surgical decompression criteria

-Acute SDH with midline shift or equal to 5 mm -Acute SDH > 1cm in thickness -

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What is the clamp that holds the head called?

Three-pin Mayfield Skull clamp

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How are burr holes made?

Perforator Perforator is placed perpendicular to the bone surface

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How is the bone flap cut?

With the craniotome

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Indications for craniotomy

Removal of abnormal brain tissue (tumor) Sample of brain tissue by biopsy Stop hemorrhage / Evacuation of hematoma / Repair blood vessels Removal of excessive CSF Drainage of abscess collection Repair skull fractures Repair meninges Implantation of medical devices or delivery of intracranial medications Treatment of neurological conditions such as epilepsy Relieve pressure associated with brain swelling/edema and increased ICP

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Normal ICP

4-14 mmHg Sustained levels > 20 mmHg can cause injury

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3 factors causing ICP

Increased brain mass/edema Increased blood volume Increased CSF volume

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Cushing's Triad

HTN Bradycardia Irregular (decreased) respirations

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Other sx of ICP

HA N/V Progressive mental status decline

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Initial management of ICP

Airway protection and adequate ventilation -Mannitol bolus (1 g/kg) Ventriculostomy and/or crainectomy may be needed

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Embolic Stroke

Acute focal neuro deficits at a clearly defined time of onset

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Goals of embolic stroke

Re-open the occluded vessel and maintain blood flow to ischemic "penumbra" tissues bordering the vascular territory

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Types of embolic strokes

Anterior cerebral artery stroke Middle cerebral artery stroke Posterior cerebral artery stroke Posterior inferior cerebellar artery stroke

34

Anterior cerebral artery stroke

supplies the medial frontal and parietal lobes, including the motor strip, as it courses into the interhemispheric fissure results in contralateral leg weakness

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Middle cerebral artery stroke

supplies the lateral frontal and parietal lobes and the temporal lobe results in contralateral face and arm weakness, language deficits Proximal MCA occlusion with ischemia and swelling in the entire MCA territory can lead to significant intracranial mass effect and midline shift

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Posterior cerebral artery stroke

supplies the occipital lobe results in a contralateral homonymous hemianopsia

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Posterior inferior cerebellar artery stroke

supplies the lateral medulla and the inferior half of the cerebellar hemispheres results in nausea, vomiting, nystagmus, dysphagia, ipsilateral Horner's syndrome, and ipsilateral limb ataxia referred to as the lateral medullary or Wallenberg's syndrome

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Intracranial tumors

Brain injury from mass effect, dysfunction or destruction of adjacent neural structures, swelling, or abnormal electrical activity (seizures)

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Supratentorial tumors

commonly present with focal neurologic deficit, such as contralateral limb weakness, visual field deficit, headache, or seizure

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Infratentorial tumors

often cause increased ICP due to hydrocephalus from compression of the fourth ventricle, leading to headache, nausea, vomiting, or diplopia

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Surgical options for tumors

Craniotomy Pituitary tumors: approached through nose via transsphenoidal approach

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Stereotactic Radiosurgery (SRS)

techniques that allow delivery of high-dose radiation that conforms to the shape of the target and has rapid isodose fall-off, minimizing damage to adjacent neural structures Gamma knife LINAC (linear accelerator)

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Gamma knife

delivers 201 focused beams of gamma radiation from cobalt sources through a specially designed colander-like helmet used only for intracranial disease and cost up to $5 million

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LINAC

delivers a focused beam of X-ray radiation from a port that arcs part way around the patient's head commonly used to provide fractionated radiation for lesions outside the CNS

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Hydrocephalus

Excess CSF in the brain that results in enlarged ventricles Communicating or obstructive Congenital or acquired

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Communicating

obstruction at the level of the arachnoid granulations causes dilation of the lateral, third, and fourth ventricles equally most common causes in adults are meningitis and SAH

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Obstructive

Ventricles proximal to the obstruction dilate, those distal remain normal in size Typical patterns include: -dilation of the lateral ventricles due to a colloid cyst occluding the foramen of Monro -dilation of the lateral and third ventricles due to a tectal (midbrain) glioma or pineal region tumor occluding the cerebral aqueduct -dilation of the lateral and third ventricles with obliteration of the fourth ventricle by an intraventricular tumor of the fourth ventricle

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Congenital

stenosis of the cerebral aqueduct, Chiari malformation, myelomeningocele, and intrauterine infection

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Acquired

may result from: occlusion of arachnoid granulations by meningitis, germinal matrix hemorrhage, SAH, or by adjacent tumors

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Treatment for hydrocephalus

Placement of a ventriculoperitoneal or ventriculoatrial shunt