Epidemiology Incidence of vertebral artery injury (VAI) 0.5% of all trauma patients 70% of VAI in blunt trauma has an 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 login to view 2 more bullets iatrogenic injury during elective surgery safe zone login to view 2 more bullets Anatomy 4 arterial segments V1 extraosseous origin at subclavian artery → anterior to C7 transverse process → 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 that 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 1.5 mm 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/intramural hematoma with <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 login to view 2 more bullets 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 x-rays 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 login to view 3 more bullets 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 Treatment Postoperative anticoagulation goal is to prevent thromboembolic sequelae of injury intravenous heparin acetylsalicylic acid (aspirin) login to view 4 more bullets contraindications: major intracranial infarction intraspinal hematoma/arteriovenous fistula Operative reduction and stabilization as necessitated by fracture pattern Surgical techniques to control hemorrhage (see techniques) Immediate intraoperative angiography can assist intraoperative decision making Postoperative management following iatrogenic injury observation further intervention dictated by clinical course immediate postoperative 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 of certain morbidities cerebellar infarction login to view 1 more bullet 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 in 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