Neurosurgery Flashcards
Treatment of cranial nerve palsies secondary to basilar skull fracture
most cranial nerve palsies are temporary due to compression or contusion, thus will improve over time as skull fracture heals
cranial nerve palsies can be treated with corticosteroids for faster recovery
Treatment of prolonged leak secondary to basilar skull fracture
indication: persistent CSF leak >7 days increases risk of CNS infection especially meningitis prophylactic antibiotics (Cefazolin or Piperacillin/Tazobactam) and surgery (covering of leak with meninge or replacement tissue)
Diagnosis of cervical spine fracture
cervical spine fractures diagnosed first on cervical spine X-rays followed by neck CT for further characterization
Indication for cervical spine xray
indication for cervical spine X-ray include any of the following:
1) mental status less than alert (GCS <15)
2) neck pain
3) midline neck tenderness
4) neurologic signs: pain, paresthesia, anesthesia, weakness in extremities
5) injury causing distracting symptoms (painful injuries in extremities)
6) Canadian C-spine rule
patients considered high risk if they have any of the following
age >65 years
paresthesia in extremities
injury mechanism by any of the following
fall >5 steps or >3 feet
axial loading (e.g. diving)
motor vehicle accidents: high speed motor vehicle collision >100km/h or rollover or ejection
accident involving bicycle or recreational motor vehicle involved (e.g. ATVs)
patients with high risk require a cervical spine X-ray
patients considered low risk if they have any of the following:
motor vehicle collision: simple rear ended without roll over, high speed and without being hit by truck or bus
patients in sitting position in emergency department
patients ambulatory at any time after injury
patients with delayed neck pain occurring after injury
no midline tenderness
low risk patients are asked to “rotate their neck left and right as far as they can, stop if any pain or numbness or tingling”
low risk patients who can rotate their neck >45 degrees in both directions actively without pain or numbness or tingling are cleared clinically and do not require C-spine X-ray
low risk patients who cannot rotate their neck >45 degrees in both directions actively require C-spine X-ray
How much soft tissue space should be posterior to the pharynx in a lateral neck xray
<1cm at C1
<0.7cm or <1/3 vertebral body width at C2-C4
<2.2cm (in adults) or <1 vertebral body width at C4-C7
What lines should be present in a lateral neck xray
Anterior vertebral line
Posterior vertebral line
Spinolaminar line
Posterior spinous line
What is the cause of a C1 or Jefferson fracture
impact or load on back of head causing axial loading
What is seen on radiograph with a C1 fracture
odontoid cervical X-ray:
widening space between odontoid process and lateral mass
lateral mass laterally displaced relative to lateral mass of C2
When is a C1 fracture considered unstable
unstable if interval between atlas and dens is increased or lateral mass extends laterally beyond axis
C1 fracture management
if stable, then soft or hard collar immobilization
if unstable (broken transverse ligament), then traction, halo vest or surgical internal fixation (rod or plate from occiput down to C2 to stabilize area)
C2 fracture cause
high force hyperextension
C2 fracture radiograph findings
3 main types of fractures on odontoid cervical X-ray
1) odontoid fracture: fracture and displacement of odontoid process in odontoid peg fracture
odontoid process fracture:
type 1 = avulsion at tip
type 2 = fracture at base (requiring surgical fusion)
type 3 = fracture extending into body of C2
2) Hangman / traumatic spondylolisthesis of axis: fracture at C2 pedicle and misalignment of C2 / C3 with anterior displacement of C2
3) avulsion of anterior corner of vertebral body of C2 “tear drop”
Management of C2 fracture
hard collar or halo vest immobilization until healing occurs (2-3 months)
for unstable, displaced, comminuted or failure to maintain alignment with external immobilization fracture (e.g. type 2 or 3 odontoid fracture): surgical fixation
post intervention, confirm recovery with repeat flexion-extension cervical X-rays
What causes a flexion teardrop fracture
hyper flexion of neck along with vertical axial compression
What are flexion teardrop fractures usually associated with
usually associated with cervical spinal cord injuries
Flexion teardrop fracture radiograph findings
lateral neck X-ray:
hyper-flexion sprain (kyphotic deformity, anterior displacement of vertebral body, widened spinous process)
avulsion fracture “teardrop” of anterior vertebral body
misalignment of spinolaminar alignment
Flexion teardrop fracture management
anterior plate stabilization; surgical fixation stabilization
What causes C spine dislocation
trauma with perching facet joint preventing bones from returning to normal position
What is C spine dislocation usually associated with
usually associated with spinal cord injury
C spine dislocation radiograph findings
lateral neck X-ray: loss of all spine alignment lines, perching of facets
C spine dislocation management
Surgical fixation and stabilization
Spinal cord injury clinical presentation
generally, higher up the spinal cord = more severe and debilitating presentation
traumatic spinal cord injury usually have complete spinal cord lesion at spinal cord level, resulting in bilateral paresis and paresthesia below the spinal cord level
spinal cord injury signs: paresthesia, anesthesia, weakness in spinal cord distribution, loss of anal sphincter tone
trauma to spine signs: step deformity on palpation, midline tenderness on palpation of spine
Spinal shock definition and diagnosis
spinal shock is short term temporary spinal cord dysfunction resulting in loss of sensation, motor function and reflexes lasting hours to days that will eventually recover
diagnosis of complete spinal cord injury must be made after spinal shock if present
if persistent loss of sensation and paralysis after return of spinal cord reflexes, then the patient does not have spinal shock and can be diagnosed with complete spinal cord injury
What are reflexes tested for for spinal shock
normal bulbocavernosus reflex = anal sphincter contracts in response to squeezing glans penis or tugging on indwelling Foley catheter
normal anal wink reflex = anal sphincter contracts upon stroking of skin around anus
normal withdrawal reflex = withdrawal and then relaxation of limb with continued noxious stimulus
What is neurogenic shock, its pathophysiology and clinical presentation
neurogenic shock is a distributive shock caused by damage to sympathetic nervous system along cervical - lumbar level
lack of sympathetic nervous stimulation results in unopposed parasympathetic stimulation resulting in bradycardia, vasodilation
vasodilation in peripheral tissue cause pooling of blood in peripheral tissues and hypotension
Clinical presentation: hypotension, bradycardia (due to unopposed parasympathetic) and warm extremities (due to pooling of blood)
Neurogenic shock treatment
treated by volume replacement if heart is healthy and strong
coupled with sympathomimetic drug (neosynephrine or dopamine) if necessary
How to clinically assess spinal cord injury
assess using ASIA (American Spinal Injury Association) standard neurological classification
What is the neurological level of spinal cord injury
neurological level of spinal cord injury is the most caudal (inferior) spinal segment with normal motor and sensation on both sides on motor and sensory testing
What are zones of partial preservation in a spinal cord injury
zone of partial preservation are dermatomes and myotomes caudal to neurological level that have partial motor or sensory function
What is considered a complete spinal cord injury
complete has no sensory nor motor function in S4-S5
What are the ASIA grades of spinal cord injury
categories A-E where A is worse and E is best
A = complete, no sensory or motor function preserved in sacral segments S4-S5
ASIA A suggest no sensory or motor function below level of injury
B = sensory incomplete, only sensory function preserved below neurological level (including S4-S5)
C = motor incomplete, some motor function is preserved under level of injury and majority of key muscles below the level have MRC score <3
D = motor incomplete, motor function preserved below neurological level and majority of key muscles below the level have MRC score >3 (MRC 3 = active movement against gravity, but not resistance)
E = normal, normal motor and sensory function
What is the meaning of the ASIA grade for spinal cord injury
ASIA grade gives prognosis
ASIA grade A (complete spinal cord injury) has significant distal recovery rate of 1-2%
ASIA grade B-E (incomplete spinal cord injury) has significant distal recovery rate of 50%
Investigations in spinal cord injury
plain X-ray films is a good for screening for any injuries to spine, which is indicated if any pain or neurological deficit on assessment
CT scan is the standard imaging for suspected spine trauma, usually follow up on abnormal or inadequate plain X-ray film
CT good for characterizing fractures
MRI usually not used in acute case of trauma due to time constraint
MRI is best imaging for spinal cord, which can assess hemorrhage, extend of cord edema & injury, traumatic disc herniation
Management of spinal cord injury
1) Stabilize patient and ensure ABC
same algorithm as brain injury (see above)
ABC should be done with C-collar on
neurogenic shock treated with fluid resuscitation and vasopressors
2) Steroids
Methylprednisolone IV as bolus then continuous for 1-2 days to reduce inflammation of spinal cord, which is controversial
3) Surgical Decompression
indication: any spine abnormality that may compress on spinal cord
decompression used to relieve pressure, preventing further damage to spinal cord due to increased pressure of compression
decompression = various surgical procedures to relieve pressure or compression of spinal cord and / or spinal nerve roots, including
diskectomy: removing part of vertebral disc to relieve pressure on nearby nerve roots
lamniotomy: removal of lamina of vertebrae to increase size of spinal canal, relieving pressure
foraminotomy: removal of bone or tissue around intervertebral foramen to relieve pressure on spinal nerve roots
osteophyte removal: removal of osteophytes
corpectomy: removal of vertebral body and disc
Branches of the external carotid artery
Some Attending Likes Freaking Out Poor Medical Students
(from proximal to distal branches)
Superior thyroid artery Ascending pharyngeal artery Lingual artery Facial artery Occipital artery Posterior auricular artery Maxillary artery Superficial temporal artery
Branches of the internal carotid artery
ophthalmic artery before joining into Circle of Willis
What arteries feed into the Circle of Willis
left & right internal carotid arteries and basilar artery feeds into circle of willis
internal carotid artery divides into L & R anterior and middle cerebral artery at circle of willis
basilar artery divides divides into L & R posterior cerebral artery at circle of willis
What are the vessels included in the Circle of Willis
L & R anterior cerebral artery anterior communicating artery L & R middle cerebral artery posterior communicating artery L & R posterior cerebral artery
L & R anterior cerebral artery + anterior communicating artery + L & R middle cerebral artery = anterior circulation of circle of willis
L & R posterior cerebral artery + posterior communicating artery = posterior circulation of circle of willis
What does the common carotid artery give rise to
L & R CCA (common carotid artery) gives rise to L & R ECA (external carotid artery) and L & R ICA (internal carotid artery), where the L & R ICA feeds into circle of willis near optic chiasm
What do the vertebral arteries give rise to
L & R vertebral artery gives rise to single basilar artery, which feeds circle of willis
the L & R vertebral artery also gives branch of L & R PICA (posterior inferior cerebellar artery), which supply the inferior cerebellum
basilar artery also gives branch of AICA (anterior inferior cerebellar artery) and SCA (superior cerebellar artery), which supply the middle and superior cerebellum respectively
Anterior cerebral arteries feed what part of the brain
anterior cerebral arteries supply most medial portion of frontal lobe and superior parietal lobe
Posterior cerebral arteries feed what part of the brain
posterior cerebral arteries supply:
medial portion of inferior parietal lobe and occipital lobe
posterior aspect of occipital lobe
Middle cerebral arteries feed what part of the brain
middle cerebral arteries continue into lateral sulcus, then give branches to supply the lateral cerebral cortex (frontal, parietal and temporal lobes) as well as insular cortex
middle cerebral arteries gives branches of lenticulostriate arteries that supply the basal ganglia and internal capsule on coronal section of brain
