Blunt cerebrovascular injury (BCVI) involves vessel injuries that occur from trauma mechanisms commonly seen in the emergency department: falls down stairs, motor vehicle collisions, and facial trauma. By identifying high-risk patients early, we can decrease the risk of stroke by up to 15% with the use of aspirin.
Objectives
- Understand the risk factors for blunt cerebrovascular injury (BCVI)
- Appreciate the pathophysiology of these injuries
- Identify clinical features and patterns of BCVI
- Explore up-to-date screening guideline literature
- Acquire a suggested ED screening algorithm for non-trauma activations
- Review management strategies for BCVI
Both cervical artery dissection (CeAD) and BCVI describe injury to the cervical carotid or vertebral arteries, with similar downstream consequences. They exist on a spectrum based on the degree of trauma and vessel health.
CeAD typically occurs in patients with underlying vessel abnormalities and can be triggered by minor events like coughing or cervical manipulation. BCVI, on the other hand, results from significant blunt force trauma to otherwise healthy vessels, commonly seen in motor vehicle collisions or high-impact trauma.
For this post, we will focus on BCVI.
Why should we care about BCVI in the ED?
Although BCVI is relatively rare, these injuries can have significant consequences if not recognized. Following older screening criteria, the incidence of BCVI was only 2-3% of all blunt trauma patients 6,7. With universal imaging, the rate of BCVI approaches 7.6% 8.
Although patients with BCVI make up only a fraction of a large trauma population, these injuries predispose patients to potentially significant neurologic consequences. A systematic review and meta-analysis by Tran in 2024 reported that the overall incidence of stroke following BCVI is 8%9.
How do vessel injuries develop?
Blunt trauma to the arteries of the neck causes an injury or tear in a layer of the vessel wall10. These injuries can then lead to:
- Dissection through the vessel wall,
- Intramural hematoma growth, and
- Exposed endothelium, which promotes platelet aggregation and thrombus formation.
Adapted from Rutman et al. 2018 10
Grading and Stroke Risk
BCVI is a spectrum of artery vessel injuries. This is important. On the basis of the appearance of these injuries, a grading scale was created by a trauma surgeon named Biffl in the 1990s11.
Adapted from Biffl et al. 1999 11
The purpose of the grading scale was to categorize stroke risk. It has been well studied that higher injury grade corresponds with increased stroke risk. As is shown below, from a study by Biffl in 200212.
Biffl et al. 2002
Adapted from Rutman et al. 2018
The downstream effects of this vessel trauma include: lumen narrowing or occlusion and embolization to the cerebral circulation. The most common mechanism of stroke from BCVI is artery-artery embolism from a thrombus.10,13
Adapted from Omran et al. 2023 13
Features for identifying BCVI
BCVI are usually asymptomatic at the time of the inciting traumatic event. So identifying these injuries upfront is very challenging, especially in an active trauma patient
But both ED and trauma teams are trying to identify these injuries in patients before any symptoms, particularly ischemic symptoms, develop. So how do we decide which patients are at risk? There are certain mechanisms and injuries that should raise our suspicion for BCVI.
We’re going to be examining three cases – a pedestrian or cyclist hit by a car, a patient who was assaulted and hit in the face, and a patient who had a fall down stairs. All of these cases of blunt traumas are ones we commonly see and manage in the ED team.
Case 1: Ms. Cece Pine (Cyclist Hit by Car)
Let’s consider the first case- you’re assessing a 43-year-old cyclist. She was hit by a car traveling about 65 km/h and thrown from her bike. She’s hemodynamically stable with a GCS of 15. She has chest wall bruising and c-spine tenderness. You decide to order CT scans for this patient, based on the mechanism of injury.
Remember – BCVI are asymptomatic at presentation. So we need other ways to identify patients at risk for these injuries…
1. Mechanism
-
- Firstly, consider the mechanism. High-energy traumatic mechanisms are associated with an increased risk of BCVI. Especially those that cause injury to the head, face, spine or chest. These include:
- High-speed MVCs, which account for more than 50% of BCVI10
- Falls down stairs or from a significant height typically >3m (particularly with neck hyperextension)
- Assaults (with force to the head or neck), and
- External compression via strangulation, seatbelts or clothesline injuries.
- Any significant force or trauma that twists or stretches the vessel, or sticks the vessel against underlying bone can result in blunt injury to the cervical arteries10. Specifically, this can include:
- The direct application of force to the neck leading to vessel impingement
- Firstly, consider the mechanism. High-energy traumatic mechanisms are associated with an increased risk of BCVI. Especially those that cause injury to the head, face, spine or chest. These include:
Adapted from Rutman et al. 2018 10
-
-
- Hyperextension or contralateral rotation of the head and neck leading to vessel stretching or twisting.
-
Adapted from Rutman et al. 2018 10
-
-
- Skull base or vertebral spine fracture which can specifically cause vessel impingement and trauma
-
Transverse foramen fracture (Rashid et al. 2022 14)
2. Other Associated Traumatic Injuries
Secondly, we should consider other traumatic injuries. Certain injuries are strongly associated with BCVI. Numerous studies have consistently identified the following injuries as significant RFs for BCVI:
- Cervical Spine Injuries
- Cеrviϲаl spine fractures have a significant link with blunt cerebrovascular injuries. A study by Esnault et al. in 2017 reported an OR of 95% CI 13.55 (3.09–59.36) for BCVI15. There are certain cervical injuries that carry an even greater risk, specifically:
- Transverse foramen frасtures (this is where the vertebral artery runs) (OR 2.6 (95% CI, 1.4-4.8))16
- Fractures in the C1-C3 region (OR 2.2 (95% CI, 1.1-4.2))16,17
- Multilevel frасtureѕ (OR 2.5 (95% CI, 1.4-4.6))16
- Cervical subluxations/dislocations (OR 3.8 95% (CI 1.9-7.8))16,17
- Cеrviϲаl spine fractures have a significant link with blunt cerebrovascular injuries. A study by Esnault et al. in 2017 reported an OR of 95% CI 13.55 (3.09–59.36) for BCVI15. There are certain cervical injuries that carry an even greater risk, specifically:
- Skull base fractures
- Basilar skull fractures, particularly those involving the clivus and petrous bones, are associated with the greatest risk for BCVI (OR 2.18 95% CI 0.46-10.27) 15,18,19.
- Recall signs of basilar skull fractures: periorbital ecchymosis, retroauricular ecchymosis, scalp deformity. These are valuable exam signs of basilar skull fracture that should raise the alarm bells for a possible BCVI.
- Cervical spine fractures, skull base fractures and thoracic injuries are the injuries most strongly associated with BCVI 15,20-22. Patients with cervical spine injury had a 5-fold greater likelihood of BCVI compared with those patients without cervical spine injury17. Patients with thoracic injury had a 2-fold greater likelihood of BCVI compared with those patients without thoracic injury20.
- General thoracic trauma
- Thoracic trauma is another significant RF for BCVI17. A study by Esnault et al. in 2017 reported an OR of 95% CI 7.35 (1.06–51.19) for BCVI. Specific thoracic injuries include the following:
- Flail chest (OR of 7.3 (95% CI, 1.1-51.2))17
- Upper rib and multiple rib fractures (OR 1.98 (95% CI, 1.35-2.92))20
- Pulmonary contusions17 and
- Thoracic spine burst fractures20
- Thoracic trauma is another significant RF for BCVI17. A study by Esnault et al. in 2017 reported an OR of 95% CI 7.35 (1.06–51.19) for BCVI. Specific thoracic injuries include the following:
Back to the case of the cyclist: the patient had a significant mechanism of injury as a cyclist hit by a car. The CT scans show 4 upper rib fractures (ribs 2-5) and a C3 transverse foramen fracture. The mechanism plus the high-risk associated injuries place her at risk for BCVI, and further work-up needs to be considered.
Case 2: Mr. Les Fort
Let’s consider the next case – you’re working an overnight shift overnight. You see a 40-year-old patient with facial trauma who was assaulted earlier that day. His face is bloody and he has swelling and deformity of the face and periorbital areas. He also has pain and bruising to the left side of his neck. You order a CT head, facial bones and c-spine. He’s been in the ED for 12h by the time his initial CT scans are back.
4. Maxillofacial fractures. These fractures are also associated with an increased risk for BCVI. Specifically:
-
- Lefort II and III fractures (Lefort III OR 16.08 (95% CI, 5.89-43.50))24,25
- Pure orbital wall fractures (OR 3.62 (95% CI, 1.32-12.69))24,25
- Signs of significant facial trauma to look out for include swelling, ecchymosis, deformity and midface instability.
Lefort II and III fractures (Le Fort Midface Fracture Classification
https://www.otoscape.com/eponyms/le-fort-midface-fracture-classification.html)
5. Mandible fractures
-
- Multiple studies have identified mandible fractures as an independent risk factor for BCVI with an OR of 4.3 (95% CI, 1.6-11.6)26,27,28.
6. Neck Trauma
-
- Neck bruising or contusions has also been reported to be a notable risk factor for BCVI22,29.
Let’s go back to our case: the assault mechanism here is concerning considering the significant facial trauma and signs of neck trauma. You wonder about a possible midface or mandibular fracture. CT angiography (CTA) is needed here for further work-up of BCVI.
For some cases with the above injury mechanisms and findings, a trauma team will be involved and may make the decision around diagnostic imaging for BCVI. In the ED, however, we likely see the majority of blunt traumas first or together with the trauma team- particularly those cases that do not meet criteria for trauma code activations, but still carry risk for BCVI. Our understanding of these risk factors is important.
Traumatic mechanism + associated high-risk injury = consider BCVI
Critical Time Window
Most patients with BCVI do not have ischemic symptoms at the initial trauma event, but can develop them later. This latent period is a valuable time to identify a possible BCVI 10,30.
So we have a window in which to identify these injuries and start treatment, in order to prevent a stroke. The average time to stroke can range from 2 hours to 1 week, but most occur between 12-72 hours 11,31,32,33. Identifying these injuries early is therefore key.
Traumatic Stroke
Higher-grade vessel injuries (such as complete vessel occlusion) can cause ischemic symptoms at the initial presentation. Any new focal or lateralizing neurologic deficits in a blunt trauma patient should prompt urgent evaluation for BCVI with a CTA. In the ED these patients can present as a possible stroke, when they actually had an initial traumatic fall.
Let’s consider an example of this: a 69-year-old woman was caught in a cargo elevator door. She presented to hospital with a GCS of 15 and mild left motor arm weakness. You have a high pretest probability that something in her head or c-spine is causing her symptoms. Her CT head and C-spine, however, show no acute injury- the normal scans are inconsistent with her exam. In these cases of blunt trauma with a new focal neuro deficit, consider a symptomatic BCVI and add the CTA to complete the assessment.
Take-Home Points:
Consider BCVI in our blunt-trauma patients in the ED with:
- High-energy mechanisms with trauma to the head, face, neck, and chest
- High-risk associated injuries
- Cervical spine injuries
- Skull base fractures
- Thoracic trauma
- Maxillofacial fractures
- Mandible fractures
- Neck trauma
There is an optimal window of 12-72 hours between a traumatic event and the development of ischemic symptoms when it is key to identify these injuries.
Stay tuned for part 2 where we dive deeper into screening and management of BCVI!
