Flashcards in Neurosurgery Deck (195):
What is the incidence of head trauma?
70,000 fatal injuries per year in US (500,000 head injuries)
What percentage of trauma deaths result from head trauma?
What is the Glasgow Coma Scale?
Objective assessment of the level of consciousness after trauma
What does unilateral, dilated, nonreactive pupil suggest?
Focal mass lesion with ipsilateral herniation and compression of CN III
What do bilateral fixed and dilated pupils suggest?
Diffusely increased ICP
What are the 4 signs of basilar skull fracture?
1. Raccoon eyes (periorbital ecchymoses)
2. Battle's sign (postauricular ecchymoses)
4. CSF rhinorrhea or otorrhea
What is the initial radiographic neuroimaging in trauma?
1. Head CT (if LOC or GCS < 15)
2. C-spine CT
3. T/L spine AP and lateral
Should the trauma head CT be with or without IV contrast?
What is normal ICP?
What is the worrisome ICP?
> 20 mmH2O
What determines ICP?
1. Volume of brain
2. Volume of blood
3. Volume of CSF
What is the CPP?
Cerebral Perfusion Pressure:
CPP = MAP - ICP
What is Cushing's reflex?
Physiologic response to increased ICP:
3. Decreased RR
What are the 3 general indications to monitor ICP after trauma?
1. GCS < 9
2. Altered level of consciousness or unconsciousness with multiple system trauma
3. Decreased consciousness with focal neurologic exam abnormality
What is Kocher's point?
Landmark for placement of ICP monitor bolt
What nonoperative techniques are used to decrease ICP?
Place drain (ventriculostomy), Paralysis
Hyperventilation to PCO2 = 35
Adequate blood pressure (CPP > 70)
Diuretic (e.g. mannitol)
Can a tight c-collar increase the ICP?
Yes (it blocks venous drainage from brain)
Why is prolonged hyperventilation dangerous?
It may result in severe vasoconstriction and ischemic brain necrosis
What is a Kjellberg?
Decompressive bifrontal craniectomy with removal of frontal bone frozen for possible later replacement
How does cranial nerve examination localize the injury in a comatose patient?
CNs proceed caudally in the brain stem as numbered.
(Presence of corneal reflex and gag reflex indicates intact pons and medulla, respectively.)
What is acute treatment for seizures after head trauma?
What is seizure prophylaxis after severe head injury?
Phenytoin for 7 days
What is the significance of hyponatremia after head injury?
SIADH must be ruled out
What is an epidural hematoma?
Collection of blood between the skull and dura
What causes an epidural hematoma?
Usually occurs in association with a skull fracture as bone fragments lacerate meningeal arteries
Which artery is associated with epidural hematomas?
Middle meningeal artery
What is the most common sign of an epidural hematoma?
> 50% have ipsilateral blown pupil
What is the classic history with an epidural hematoma?
LOC, followed by a lucid interval, followed by neurologic deterioration
What are the classic CT findings with an epidural hematoma?
What is the surgical treatment for an epidural hematoma?
What are the indications for surgery with an epidural hematoma?
Any symptomatic epidural hematoma or hematoma > 1 cm
What is a subdural hematoma?
Blood collection under the dura
What causes a subdural hematoma?
Tearing of bridging veins that pass through the space between the cortical surface and the dural venous sinuses or injury to the brain surface with resultant bleeding from cortical vessels
What are the 3 types of subdural hematomas?
1. Acute: symptoms within 48 hours
2. Subacute: symptoms with 3-14 days
3. Chronic: symptoms after 2 weeks or longer
What is the treatment for epidural and subdural hematomas?
Craniotomy with clot evacuation is usually required
What are classic CT findings with a subdural hematoma?
Curved, crescent-shaped hematoma
What is traumatic subarachnoid hemorrhage?
Head trauma resulting in blood below the arachnoid membrane and above the pia
What is the treatment for subarachnoid hemorrhage?
Anticonvulsants and observation
What is a cerebral contusion?
Hemorrhagic contusion of brain parenchyma
What are coup and contrecoup injuries?
Coup: injury at the site of impact
Contrecoup: injury at the site opposite the point of impact
What is DAI?
Diffuse Axonal Injury:
Shear injury to brain parenchyma from rapid deceleration.
What is the best diagnostic test for DAI?
What can present after blunt trauma with neurological deficits and a normal brain CT?
DAI, carotid artery injury
What is a depressed skull fracture?
Fracture in which one or more fragments of the skull are forced below the inner table of the skull
What are the indications for surgery after a skull fracture?
1. Contaminated wound requiring cleaning and debridement
2. Severe deformity
3. Impingement on cortex
4. Open fracture
5. CSF leak
What is the treatment for open skull fractures?
2. Seizure prophylaxis
3. Surgical therapy
What are the 2 general types of spinal cord injuries?
1. Complete: no motor/sensory function below the level of injury
2. Incomplete: residual function below the level of injury
What is spinal shock?
Loss of all reflexes and motor function, hypotension, bradycardia
What does "sacral sparing" mean?
Sparing of sacral nerve level: anal sphincter intact, toe flexion, perianal sensation
What initial studies/interventions are important in spinal cord injuries?
2. Maintain BP (IVF, pressers if refractory to fluids)
3. NG tube (prevents aspiration)
5. High-dose steroids
6. Complete cervical XRs and those of lower levels as indicated by exam
What are the diagnostic studies for spinal cord injury?
X-rays, CT, MRI
What are the indications for emergent surgery with spinal cord injury?
Unstable vertebral fracture; incomplete injury with extrinsic compression; spinal epidural or subdural hematoma
What is the indication for IV high-dose steroids with spinal cord injury?
Controversial: Blunt spinal cord injury with neurologic deficit (methylprednisolone: high-dose bolus followed by continuous infusion for 23 hours)
Have steroids been proven to help after penetrating spine injury?
What is anterior cord syndrome?
Affects corticospinal and lateral spinothalamic tracts; paraplegia; loss of pain and temperature sensation; preserved touch, vibration, and proprioception
What is central cord syndrome?
Preservation of some lower extremity motor and sensory ability with upper extremity weakness
What is Brown-Sequard syndrome?
Hemisection of cord resulting in ipsilateral motor weakness and touch and proprioception loss with contralateral pain and temperature loss
What is posterior cord syndrome?
Injury to posterior spinal cord with loss of proprioception distally
What is a Jefferson's fracture?
Fracture through C1 arches from axial loading (unstable)
What is a hangman's fracture?
Fracture through the pedicles of C2 from hyperextension (usually stable)
What is an odontoid fracture?
Fracture of the odontoid process of C2 (view with open-mouth odontoid XR)
What is a Chance fracture?
Transverse vertebral fracture
What is a clay shoveler's fracture?
Fracture of the spinous process of C7
What is a type I odontoid fracture?
Fracture through tip of dens
What is a type II odontoid fracture?
Fracture through base of dens
What is a type III odontoid fracture?
Fracture through body of C2
What is the incidence of CNS tumors?
1% of all cancers
What is the usual location of primary CNS tumors in adults? children?
Adults: 66% are supratentorial
Children: 66% are infratentorial
What is the differential diagnosis of a ring-enhancing brain lesion?
Metastatic carcinoma, abscess, GBM, lymphoma
What are the adverse effects of tumors on the brain?
1. Increased ICP
2. Mass effect on cranial nerves
3. Invasion of brain parenchyma, disrupting nuclei/tracts
4. Seizure foci
5. Hemorrhage into or around tumor mass
What are the signs and symptoms of intracranial tumors?
1. Neurologic deficit
4. Vomiting (classically in the morning)
How is the diagnosis of intracranial tumor made?
What are the surgical indications with intracranial tumors?
1. Establishing a tissue diagnosis
2. Relief of increased ICP
3. Relief of neurologic dysfunction caused by tissue compression
4. Attempt to cure in the setting of localized tumor
What are the most common intracranial tumors in adults?
Metastatic neoplasms are most common.
Primary: Glioma (50%) , meningioma (25%)
What are the 3 most common intracranial tumors in children?
1. Medulloblastoma (33%)
2. Astrocytoma (33%)
3. Ependymoma (10%)
What is a glioma?
General name for several tumors of neuroglial origin (e.g. astrocytes, ependymal, oligodendrocytes)
What are the characteristics of low-grade astrocytoma?
Nuclear atypia, high mitotic rate, high signal on T2 weighted images, non-enhancing with contrast on CT
What is the most common primary brain tumor in adults?
Glioblastoma multiforme (GBM)
What are the characteristics of GBM?
Poorly defined, highly aggressive tumors occurring in the white matter of the cerebral hemispheres.
Spread extremely rapidly.
What is the average age of onset with GBM?
What is the treatment for GBM?
Surgical debunking followed by radiation
What is the prognosis for GBM?
Without treatment: >90% die within 3 months
With treatment: 90% die within 2 years
What cell of origin in meningiomas?
Arachnoid cap cells
What are the risk factors for meningioma?
Radiation exposure, neurofibromatosis type 2, female
What are the associated histologic findings with meningioma?
Psammoma bodies (concentric calcifications), whorl formations (onion-skin pattern)
What is the histologic malignancy determination with meningiomas?
Brain parenchymal invasion
What is the peak age of occurrence for meningioma?
What is the clinical presentation of meningioma?
Variable depending on location:
Lateral cerebral convexity: focal deficits or headache.
Posterior fossa: CN deficits.
Olfactory groove: anosmia.
What is the treatment for meningioma?
Preoperative embolization and surgical resection
What is the peak age for cerebellar astrocytoma occurrence?
What is the usual location for cerebellar astrocytomas?
Cerebellar hemispheres, less frequently in the vermis
What are the signs and symptoms of cerebellar astrocytoma?
Ipsilateral incoordination or dysmetria (patient tends to fall to side of tumor) as well as nystagmus and ataxia.
CN deficits (especially VI and VII).
What is the treatment for cerebellar astrocytoma?
Completely resectable in 75% of cases
What is the peak age for medulloblastoma?
What is the cell of origin in medulloblastoma?
External granular cells of cerebellum
What is the most common location for medulloblastoma?
Cerebellar vermis in children.
Cerebellar hemispheres of adolescents and adults.
What are the signs and symptoms of medulloblastoma?
Headache, vomiting, and other signs of increased ICP.
Usually truncal ataxia.
What is the treatment for medulloblastoma?
Surgery to debulk tumor, cranial and spinal radiation, chemotherapy
What is the prognosis for medulloblastoma?
5-year: > 50%
What is the most common pituitary tumor?
What is the most common presentation of a prolactinoma?
Bitemporal hemianopsia (lateral visual fields blind)
What are the blood prolactin levels with a prolactinoma?
> 300 mg/L (> 100 mg/L is abnormal)
What is the medical treatment for prolactinoma?
What is the surgical treatment for prolactinoma?
Trans-sphenoidal resection of the pituitary tumor
What is the treatment for a recurrent prolactinoma after surgical resection?
What are the usual causes of subarachnoid hemorrhage?
Trauma; ruptured berry aneurysm; arteriovenous malformations
What is a berry aneurysm?
Saccular out-pouching of vessels in the circle of Willis, usually at bifurcations
What is the usual location of a berry aneurysm?
Anterior communicating artery (30%), posterior communicating artery, middle cerebral artery
What medical disease increases the risk of berry aneurysms?
Polycystic kidney disease and connective tissue disorders
What is an arteriovenous malformation?
Congenital abnormality of the vasculature with connections between the arterial and venous circulations without interposed capillary network
Where do brain AVMs occur?
>75% are supratentorial
What are the signs and symptoms of subarachnoid hemorrhage?
"Worst headache of life", meningismus, LOC, N/V, photophobia
What comprises the workup of subarachnoid hemorrhage?
Head CT, LP (not necessary if CT is definitive), arteriogram
What are the possible complications of subarachnoid hemorrhage?
1. Brain edema leading to increased ICP
2. Rebleeding (most common in the first 24-48 hour)
3. Vasospasm (most common cause of morbidity and mortality)
What is the treatment for brain vasospasm?
What is the treatment for brain aneurysms?
Surgical treatment by placing a metal clip on the aneurysm.
Also, balloon occlusion, coil embolization.
What is the treatment for AVMs?
Preoperative embolization (reduce size), followed by surgical resection.
If inaccessible, radiosurgery is effective for AVMs < 3 cm in diameter.
What is intracerebral hemorrhage?
Bleeding into the brain parenchyma
What is the etiology of intracerebral hemorrhage?
Hypertension and atherosclerotic disease (Charcot-Bouchard aneurysms).
Also, coagulopathy, AVMs, amyloid angiopathy, bleeding into tumor, trauma.
Where do intracerebral hemorrhages occur?
66% in basal ganglia (most commonly putamen)
What is the usual presentation of intracerebral hemorrhage?
66% present with coma.
Large putamen bleeding classically presents with contralateral hemiplegia and hemisensory deficits, lateral gaze preference, aphasia, and homonymous hemianopsia.
What is the associated diagnostic study for intracerebral hemorrhage?
What are the surgical indications for intracerebral hemorrhage?
CN III palsy, progressive alteration of consciousness
What is the prognosis for intracerebral hemorrhage?
Poor, especially with ventricular or diencephalons involvement
What is lumbar disc herniation?
Extrusion of the inner portion of the intervertebral disc (nucleus pulposus) through the outer annulus fibrosis, causing impingement on nerve roots exiting the spinal canal
Which nerve is affected in lumbar disc herniation?
Nerve exiting at the level below (e.g. an L4-L5 disc impinges on the L5 nerve exiting between L5-S1)
Who is affected by lumbar disc herniation?
Middle-aged and older individuals
What is the usual cause of lumbar disc herniation?
Loss of elasticity of the posterior longitudinal ligaments and annulus fibrosis as a result of aging
What are the most common sites of lumbar disc herniation?
What is the usual presenting symptom for lumbar disc herniation?
Low back pain
What are the signs of L5-S1 herniation?
Decreased ankle jerk reflex; weakness of plantar flexors in foot; pain in back/midgluteal region to posterior calf to lateral foot; ipsilateral radiculopathy on straight leg raise
What are the signs of L4-L5 herniation?
Decreased biceps femoris reflex; weak extensors of foot
What are the signs of L3-L4 herniation?
Decrease or absence of knee jerks; weakness of the quadriceps femoris; pain in lower back/buttocks; pain in lateral thigh and anterior thigh; pain in hip/groin region to posterolateral thigh, lateral leg, and medial toes
How is the diagnosis of lumbar disc herniation made?
CT, CT myelogram, MRI
What is the treatment for lumbar disc herniation?
Conservative: bed rest, analgesics
Surgical: partial hemilaminectomy and discectomy
What are the indications for emergent surgery for lumbar disc herniation?
1. Cauda equina syndrome
2. Progressive motor deficits
What is caudal equina syndrome?
Herniated disc compressing multiple S1, S2, S3, S4 nerve roots, resulting in bowel or bladder incontinence, saddle anesthesia over buttocks and perineum, low back pain, sciatica
What is sciatica?
Radicular or nerve root pain
What is cervical disc disease?
Same pathology as lumbar disc her nation, except in the cervical region.
The disc impinges on the nerve exiting the canal at the same level of the disease.
What are the most common sites of cervical disc disease?
What are the signs and symptoms of C7 disease?
Decreased triceps reflex and strength; weakness of forearm extension; pain from neck, through triceps and into index and middle finger
What are the signs and symptoms of C6 disease?
Decreased biceps and brachioradialis reflex; weakness in forearm flexion; pain in neck, radial forearm, and thumb
What are the signs and symptoms of C8 disease?
Weakness in intrinsic hand muscles; pain in 4th and 5th fingers
How is the diagnosis of cervical disc disease made?
What is the treatment for cervical disc disease?
Anterior or posterior discectomy with fusion PRN
What are the symptoms of central cervical cord compression from disc fragments?
Myelopathic syndrome with LMN signs at level of compression and UMN signs distally
What is Spurling's sign?
Reproduction of radicular pain by having the patient turn his head to the affected side and applying axial pressure to the top of the head
What is the etiology of spinal epidural abscess?
Hematogenous spread from skin infections is most common.
Also, distant abscesses or infections, UTIs, postoperative infections, spinal surgery, epidural anesthesia.
What is the commonly associated medical condition with spinal epidural abscess?
What are the 3 most common sites of spinal epidural abscesses?
What is the most common organism in spinal epidural abscesses?
What are the signs and symptoms of spinal epidural abscesses?
Fever; severe pain over affected area and with flexion/extension of spine; weakness can develop, ultimately leading to paraplegia
How is the diagnosis of spinal epidural abscess made?
Which test is contraindicated with spinal epidural abscess?
LP (risk of seeding CSF with bacteria)
What is the treatment fro spinal epidural abscess?
Surgical drainage and appropriate antibiotic coverage
What is the prognosis for spinal epidural abscess?
If severe neurologic deficits preoperatively, little recovery.
What is hydrocephalus?
Abnormal condition consisting of an increased volume of CSF along with distention of CSF space.
What are the 3 general causes of hydrocephalus?
1. Increased production of CSF
2. Decreased absorption of CSF
3. Obstruction of normal flow of CSF
What is the normal daily CSF production?
What is the normal volume of CSF?
What is communicating hydrocephalus?
Unimpaired connection of CSF pathway from lateral ventricle to subarachnoid space
What is noncommunicating hydrocephalus?
Complete or incomplete obstruction of CSF flow within or at the exit of the ventricular system
What are the specific causes of hydrocephalus?
Congenital malformations; aqueductal stenosis; myelomeningocele; tumors obstructing CSF flow; inflammation causing impaired absorption of fluid; subarachnoid hemorrhage; meningitis; choroid plexus papilloma (increased CSF production)
What are the signs and symptoms of hydrocephalus?
Sings of increased ICP (HA, N/V, ataxia, increasing head circumference)
How is the diagnosis of hydrocephalus made?
CT, MRI, measurement of head circumference
What is the treatment for hydrocephalus?
1. Remove obvious offenders
2. Perform bypass obstruction with ventriculoperitoneal or ventriculoatrial shunt
What is the prognosis for hydrocephalus if untreated?
Survivors show decreased IQ, ataxia, paraparesis, visual deficits
What are the possible complications of treatment of hydrocephalus?
1. Blockage or shunt malfunction
What is hydrocephalus ex vacuo?
Increased volume of CSF spaces from brain atrophy, not from any pathology in the amount of CSF absorbed or produced
What is a shunt series?
Series of XRs covering the entire shunt length looking for shunt disruption or kinking to explain malfunction of shunt
What is the incidence of neural tube defects?
What are the race/gender demographics for neural tube defects?
More common in whites and females
What is spina bifida occulta?
Defect in the development of the posterior portion of the vertebrae
What are the signs and symptoms of spina bifida occulta?
Usually asymptomatic, though it may be associated with other spinal abnormalities.
Usually found incidentally on XRs.
What is the most common clinically significant neural tube defect?
What is a myelomeningocele?
Herniation of nerve roots and spinal cord through a defect in the posterior elements of the vertebra.
The sac surrounding the neural tissue may be intact, but more commonly is ruptured and therefore exposes the CNS to the external environment.
What are the 3 most common sites for myelomeningocele?
1. Lumbar region
2. Lower thoracic region
3. Upper sacral region
What are the signs and symptoms of myelomeningocele?
Variable from mild skeletal deformities to a complete motor/sensory loss.
Bowel/bladder function is difficult to evaluate, but often is affected and can adversely affect survival.
What is the treatment for myelomeningocele?
If open, patients are operated on immediately
What is the prognosis for myelomeningocele?
2-year: 95% survival with surgery (25% without)
Which vitamin is though to lower the rate of neural tube defects in utero?
What is craniosynostosis?
Premature closure of one or more of the sutures between the skull plates
What is the incidence of craniosynostosis?
What are the types of craniosynostosis?
Named for closed suture (e.g. sagittal, coronal lambdoid, etc.)
How is the diagnosis of craniosynostosis made?
Physical (ridges along fused sutures and lessened suture mobility).
X-rays (lack of lucency along fused suture).
What are the indications for surgery for craniosynostosis?
Cosmetic, as cranial vault with continue to deform with growth.
What is the timing of surgery for craniosynostosis?
Usually 3-4 months of age.
Earlier surgery increases the risk of anesthesia.
Later surgeries are more difficult because of the worsening deformities and decreasing malleability of skull.
What is the operative mortality with craniosynostosis?
What is the most common bacteria causing post-neurosurgery meningitis?
What classically presents as the "worst headache of life"?
Spontaneous subarachnoid hemorrhage
What classically has a lucid interval?
What is the most common location of a hypertensive intracerebral hemorrhage?
What is a 3rd-nerve palsy?
What is Millard-Gubler syndrome?
1. CN VI palsy
2. CN VII palsy
3. Contralateral hemiplegia