Updated: 12/7/2022

Vertebral Artery Injury

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  • Epidemiology
    • Incidence of vertebral artery injury (VAI)
      • 0.5% of all trauma patients
        • 70% of VAI in blunt trauma has associated cervical fracture
        • 33%-39% of all cervical spine fractures
      • 0.3% anterior cervical spine surgery
      • 4.1-8.2% posterior cervical spine surgery (C1-2 transarticular screws)
  • Etiology
    • Pathophysiology
      • blunt traumatic injury
        • pathoanatomy
          • highest injury risk at point of entry into C6 transverse foramen
          • second highest risk at C1-2 articulation
      • iatrogenic injury during elective surgery
        • safe zone
          • C1: avoid dissection cephalad to the C1 posterior arch > 1.5 cm lateral to midline
          • C1 lateral mass screw should be placed in a 10 degrees medial and 22 degrees cephalad trajectory
  • Anatomy
    • 4 arterial segments
      • V1
        • extraosseous
        • origin at subclavian artery, anterior to C7 transverse process, to the entry point of C6 transverse foramen
      • V2
        • within the transverse foramina of C6-C1
        • most traumatic injuries occur here
        • high risk during drilling, tapping, insertion of lateral mass or pedicle screws
      • V3
        • superior aspect of the arch of atlas to foramen magnum
        • VA is vulnerable during lateral exposure and laminectomy of C1
        • high risk of C1-2 transarticular screws are directed caudally and laterally
      • V4
        • intradural extension from foramen magnum to unite with contralateral vertebral artery
        • forms the basilar artery
      • most injuries from cervical trauma in V2 (foraminal segment)
    • Anomalous anatomy
      • reported prevalence of 2.7% in anterior cervical surgery
        • transverse foramen may be medial to or within 1.5mm of the uncovertebral joint
      • reported prevalence of 2.3-20% in the atlantoaxial region
        • high-riding C2 foramen
        • C2 pedicle erosion
        • C2 lateral mass thinning
  • Classification
      • Biffl VAI Injury Grading
      • Grade I
      • Arteriographic appearance of vessel dissection/intraumural hematoma; <25% luminal stenosis
      • Grade II
      • Intraluminal thrombosis or raised intimal flap; dissection/intramural hematoma with >25% luminal stenosis
      • Grade III
      • Pseudoaneurysm
      • Grade IV
      • Vessel occlusion
      • Grade V
      • Vessel transection
  • Presentation
    • History
      • consists of recent:
        • cervical spine trauma
          • C1 or C2 fractures
          • subaxial facet fractures and dislocations
        • elective surgery of the cervical spine or craniocervical junction
    • Symptoms
      • variable in presentation and time of onset
      • vertebrobasilar insufficiency manifests with
        • dizziness
        • vertigo
        • nausea
        • diplopia
        • blindness
        • ataxia
        • bilateral weakness
        • oropharyngeal dysfunction
  • Imaging
    • Radiographs
      • xrays of certain fracture patterns raise suspicion for VAI
    • CT angiography (CTA)
      • identification of local occlusion or extravasation 
      • sensitivity reported at 100%
      • indications for the trauma patient (any single criteria is an indication)
        • unexplained central or lateralizing neurologic deficit
        • evidence of acute cerebral infarct on CT scan of head
        • GCS <9
        • evidence of diffuse axonal injury
        • facial fracture or Le Fort type-II or III fracture
        • cervical spine fracture or subluxation
          • C1, 2, 3 fracture
          • Fracture extension into the transverse foramen
          • VAI demonstrated in 20%
        • cervical spinal cord injury
        • hanging injuries
        • major thoracic injury or first-rib fracture
    • Magnetic resonance angiography (MRA)
      • identification of local occlusions/stenosis
      • sensitivity 93.9%
      • indications
        • cervical spine fractures with neurologic deficits attributable to damaged vertebral or basilar artery perfusion
      • sensitivity and specificity
  • Treatment
    • Post-operative anticoagulation
      • goal is to prevent thromboembolic sequelae of injury
        • intravenous heparin
        • acetylsalicylic acid (aspirin)
          • indications
            • first line of treatment
          • modalities
            • heparin, aspirin, clopidogrel, IV thrombolysis, glycoprotein IIb/IIIa antagonists (abciximab, eptifibatide, tirofiban)
      • contraindications:
        • major intracranial infarction
        • intraspinal hematoma/arteriovenous fistula
    • Operative reduction and stabilization as neccessitated by fracture pattern
    • Surgical techniques to control hemorrhage (see Techniques)
    • Immediate intra-operative angiography
      • can assist intra-operative decision making
    • Post-operative management following iatrogenic injury
      • observation
        • further intervention dictated by clinical course
      • immediate post-operative angiography
        • detects vascular complications
        • confirms adequate collateral cerebral circulation
        • allows embolization of fistulae or pseudoaneurysm
  • Techniques
    • Hemostatic tamponade
      • utilization of topical hemostatic agents, bone wax
      • if injured during C1-2 transarticular screw placement, can tamponade by screw insertion
      • risks include:
        • delayed hemorrhage
        • fistula formation
    • Microvascular repair
      • allows restoration of normal blood flow
      • minimizes risk of ischemic complications
      • technically demanding
    • Direction ligation
      • consider intraoperative angiography first to evaluate collateral circulation
      • risks certain morbities
        • cerebellar infarction
          • loss of flow via the posterior inferior cerebellar atery (PICA)
        • isolated cranial nerve paresis
        • hemiplegia
    • IR-guided embolization
  • Complications
    • Complications may occur days to years following injury
      • arteriovenous fistula
      • late-onset hemorrhage
      • pseudoaneurysm
        • may be delayed presentation
      • thrombosis with embolic incidents
      • cerebral ischemia/Stroke
        • persistent vertigo
      • death
  • Prognosis
    • Impact of VAI difficult to predict
    • Many patients initially asymptomatic
      • some progress to cerebral ischemia or stroke with permanent neurologic deficit
    • Variable symptomatology

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Flashcards (56)
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Questions (5)

(SBQ18SP.23) During a C1-C2 posterior spinal fusion, while performing the dissection of posterior arch of C1 and pedicle of C2, the surgeon encounters rapid pulsatile arterial bleeding. The artery is tamponaded off,vascular surgery is consulted and an intra-operative angiogram is performed. Given adequate collateral flow, the injured artery is embolized. Post-operatively the patient's neurologic function is normal. Injury to this arterial structure could have best been avoided by minimizing dissection in which of the following areas?

QID: 211355

Dorsolaterally along the C1-C2 facet, medial to the foramen transversarium



Ventral along the medial border of the the pars of C2



Cephalad to the posterior arch of C1 when > 1.5cm lateral to the midline



Caudal to the posterior arch of C1 when < 1.0cm lateral to the midline



Cephalad to the posterior arch of C1 when < 1.0cm lateral to the midline




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(SBQ18SP.56) During the posterior exposure of the atlas arch in the cervical spine, excessive retraction of >2 cm past midline would cause injury to an anatomical structure. Which of the following statements is true about this structure?

QID: 211718

Injury to this structure causes postoperative hoarseness



The structure is a branch of the vagus nerve



Injury to this structure causes weakness in forearm supination



The structure typically originates from the subclavian artery and travels cephalad through the transverse foramen



The structure is a terminal branch of the common carotid artery



L 1 A

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(SBQ12SP.64) A 75-year old female presents to the ER after a motor vehicle collision where she was rear-ended. Her imaging studies are shown in Figures A through C. She undergoes posterior stabilization and instrumented fusion (PSIF) without complications. During surgery, C1 lateral mass screws are placed with a starting point directly beneath the medial edge of the posterior arch at the point where it joins the lateral mass. The screws are directed 10 degrees medial and 22 degrees cephalad in order to be:

QID: 3762

Inferior and medial to the vertebral artery



Inferior and lateral to the vertebral artery



Superior and medial to the vertebral artery



Superior and lateral to the vertebral artery



Superior and aligned in the coronal plane



L 5 C

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Evidence (5)
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