A restrained driver in a high-speed motor vehicle accident was evaluated in the emergency department where he was found to have a Glasgow Coma scale score (GCS) of 6 and significant facial fractures. His injuries were limited to the head, and a computed tomography (CT) scan of the abdomen and pelvis was otherwise negative, and the CT scan of his head showed no intracranial injury. He was admitted and intubated in the intensive care unit (ICU) where he awoke over the next 12 hours. On hospital day 1, he was found to have a new-onset right hemiparesis and aphasia. He was taken for a stat repeat head CT that did not reveal any bleeding but did demonstrate a small left temporal infarct. Angiography showed a left internal carotid artery (ICA) dissection with near-total occlusion in the carotid siphon (Figure 28-1). He was started on antiplatelet therapy (aspirin) and once there was no evidence of bleeding, he was anticoagulated on heparin. Serial head CT scans showed stable infarct size, and he slowly recovered over the next several days.
FIGURE 28-1
The typical location of a carotid dissection (shown by the arrow) is at the relatively fixed point of the internal carotid artery (ICA) near the siphon (S-shaped portion as it enters the skull base). This dissection is focal and is only causing about a 30% stenosis. Management would include anticoagulation or possibly antiplatelet agents for 6 months if the patient can tolerate it.
Accounts for 3% to 10% of all carotid injuries.
Overall incidence of carotid artery injury in blunt trauma is 0.08% to 0.33%.
Half of the affected patients show no signs of cervical trauma or neurologic deficit at presentation.
90% of blunt injuries involve the ICA.
The most common location is as it enters the siphon.
Bilateral injury has been reported in 20% to 50% of cases.
There is an increase in the incidence of reported blunt carotid injuries due in part to better recognition and screening (Figure 28-2).
FIGURE 28-2
In a more severe dissection there can be complete occlusion of the internal carotid artery. The patient above has a normal common carotid artery (CCA) and external carotid artery (ECA). The internal carotid artery (ICA) has a proximal injury that has led to complete occlusion of the distal ICA.
The incidence of major vascular trauma following a penetrating injury is 20%.
The low incidence, anatomic site, and variable presentation have made optimal diagnostic and management strategies difficult.
The most common mechanism involves hyperextension and rotation of the cervical spine.
Basilar skull fractures.
Direct blows to the artery.
Intraoral trauma.
Dissection
Thrombosis
Pseudoaneurysm
Carotid-cavernous sinus fistula
Complete arterial disruption
The mortality rate of blunt carotid injury varies from 20% to 40% due in part to the extent of concurrent injuries. Permanent neurologic im-pairment occurs in 25% to 80% of survivors; therefore, the importance of detecting the injury prior to symptoms is crucial in preventing long-term complications.
The management and workup of penetrating neck injuries is dependent on two factors: level of injury and need for emergent operative exploration.
Criteria for emergent exploration are
Shock
Refractory hypotension
Pulsatile bleeding
Bruit
Enlarging hematoma
Neurologic deficit
Hard signs of a tracheobronchial injury (respiratory distress or air bubbles from the wound)
Clinical features suggestive of injury in hemodynamically stable patients are:
History of bleeding at the scene
Stable hematoma
Nerve injury
Proximity of the injury track
Unequal upper extremity blood pressure measurements
Painful swallowing
Subcutaneous emphysema
Hematemesis
Nerve injury (cranial nerves or brachial plexus injury)
Ninety-seven percent of patients with hard signs have a vascular injury. About 3% of those with soft signs are found to have an in-jury.1 A negative physical examination with observation has a negative predictive value of 90% to 100% for vascular inju-ries.2
There are multiple studies that have attempted to develop a consensus as to which signs and symptoms warrant screening for blunt carotid injury.
Denver Health Medical Center3
This was the first attempt at establishing criteria.
18% of screened patients were found to have an injury.
Half of the patients were asymptomatic at presentation.
The criteria that prompted screening included
Hemorrhage or expanding hematoma
Cervical bruit
Examination inconsistent with head CT findings
Stroke on follow-up head CT
Focal neurologic deficit
They defined risk factors as below:
Le Fort II or III fractures
Basilar skull fracture
Diffuse axonal injury with GCS less than 6
Cervical spine fracture
Near-hanging with anoxic brain injury
The Memphis criteria4
Had a higher rate of injury using their protocol (29%).
This protocol required screening for
Neurologic examination not explained by brain imaging
Horner syndrome
Neck soft tissue injury
Le Fort II or III fracture
Basilar skull fracture
Cervical spine fracture
This protocol also had high rates of screening with low positive results.
Biffl et al. performed a multivariate analysis on a prospectively screened population and found four clinical findings predictive of carotid in-jury5:
GCS less than 6
Le Fort II or III fractures
Petrous fractures
Diffuse axonal injury
Patients with one finding had a 41% risk of carotid injury, two findings had 56% to 74%, three findings had 80% to 88%, and all four had 93% risk.
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