What is Vertebral Artery Injury?
Injury to the vertebral artery, the major artery in your neck, can either be due to a traumatic event or it can occur spontaneously. Traumatic injuries usually happen due to a blow to the head or neck or a penetrating wound. Spontaneous injuries occur when the wall of the artery weakens by itself, often due to an existing blood vessel or connective tissue disease, causing the artery’s layers to separate, known as a dissection.
Dissections that happen spontaneously are often linked to minor triggers. The severity of the injury can vary from a minor irregularity in the artery wall to a complete tear with bleeding both in and outside of the brain. Initially, patients often experience a headache and neck pain, but some might not show any symptoms.
Vertebral artery injury is a significant cause of stroke and transient ischemic attack (temporary stroke-like symptoms), especially among younger people. Since the vertebral arteries send blood supply to the back part of the brain, patients can present with symptoms associated with this part of the brain not getting enough blood. This can include difficulties with speech, swallowing, keeping balance, coordination loss, or vision changes.
The modified Denver screening criteria is a set of guidelines doctors use to find patients who have a high risk for injuries affecting the brain’s blood supply. The first choice for a diagnostic imaging test is usually a CT angiogram, which is an X-ray of the blood vessels. The treatment for vertebral artery injury can vary depending on the location, symptoms, and how severe the injury is. Therapy can include fibrinolysis (dissolving blood clots), anticoagulation (preventing blood clots), antiplatelet therapy (preventing blood cells from clumping together), endovascular therapy (minimally invasive treatment), or open surgical repair.
What Causes Vertebral Artery Injury?
Vertebral artery injuries, or injuries to key arteries in the neck, can happen for a few reasons. They might be caused by blunt force, such as from a car crash, penetrating injuries like a gunshot wound, or they may even happen on their own. Car crashes make up the majority of these cases, while other causes like falls, strangulation, and pedestrian accidents are less common.
The way in which these arteries get injured can vary. For example, a closed injury (an injury that does not break the skin or the surface of the involved organ) often happens due to the neck being stretched out and bent in a certain way, or the head getting twisted.
Though it’s rare, the vertebral arteries can also get punctured, like from a gunshot. Even certain everyday activities or experiences have been linked to these injuries, including certain sports, abusing a trampoline, riding amusement park rides, coughing, sneezing, vomiting, childbirth, sexual intercourse, yoga, scuba diving, and even neck manipulation as performed by a chiropractor.
In some cases, vertebral artery injuries happen ‘spontaneously’, meaning without a clear reason or cause. This might occur if the structure of the artery wall has been compromised in some way. Although cases have been found in people with certain vascular or connective tissue disorders, such as fibromuscular dysplasia, Ehlers-Danlos syndrome, or Marfan syndrome, most people diagnosed with a spontaneous artery injury of the neck have no known history of pre-existing conditions. Often, these spontaneous cases occur after a mild trauma.
Risk Factors and Frequency for Vertebral Artery Injury
Spontaneous dissections, or tears, of the brain’s arteries can cause around 20% of strokes in young adults. This often involves the carotid or vertebral arteries. However, vertebral artery dissections are less common, happening in about 1 in 100,000 people. Because many cases are symptom-free, the actual incidence rate could be higher. This condition typically affects people aged 44 to 46, with no significant difference based on race or gender. There’s a higher occurrence in the winter, but the reason for this seasonal pattern isn’t clear.
On the other hand, trauma-induced injuries to the vertebral artery are quite rare, occurring in less than 1% of trauma admissions. Yet, the incidence rate seems to be increasing due to growing awareness and screening in high-risk patients. Vertebral artery injury can occur in up to 11% of patients who experience severe physical trauma, such as those meeting certain clinical and examination criteria. A screening method called the modified Denver screening criteria is used to pinpoint patients with a high risk for brain artery injuries.
- Patients with cervical transverse foramen fractures, or breaks in the vertebrae, or facet dislocations, which refer to malalignment of spinal bones, have an associated vertebral artery injury in 27.5% of cases.
Signs and Symptoms of Vertebral Artery Injury
A vertebral artery injury can occur spontaneously or due to acute trauma. While some spontaneous cases may be linked to minor injuries, they are often more common in patients with connective tissue disorders. However, most patients don’t have a known history of connective tissue disease.
Common symptoms include head and neck pain, dizziness, and vertigo. However, some patients may not exhibit any symptoms. In certain cases, the first sign of this condition is a temporary disruption in the blood supply to part of the brain (transient ischemic attack) or a stroke. The risk of stroke is the highest in the first two weeks after the injury. Young patients with acute stroke should consider this condition, especially if they also experience a headache or neck pain. Notably, while neck pain is a common symptom, only 46% of patients report it initially. Other symptoms can include scalp sensitivity, ringing in the ears (tinnitus), neck noises during cardiac systole (bruits), cervical nerve root involvement, or even conditions related to poor blood supply to the brain or spinal cord.
Patients with acute trauma should firstly be assessed and stabilized according to Advanced Trauma Life Support guidelines. Like spontaneous cases, some patients may not show initial neurologic symptoms. One study found almost half the patients experienced a delay of around 18 hours between injury and the onset of neurologic symptoms. Patients with blunt neck injuries who meet specified screening criteria are advised to receive an evaluation for cerebrovascular injury.
- Lateralizing neurologic deficit (not explained by head CT)
- Infarct on head CT
- Nonexpanding cervical hematoma
- Massive nosebleed (epistaxis)
- Unequal size of the pupils / Horner syndrome
- Glasgow coma score (GCS) less than 8 without significant CT finding
- Cervical spine fracture
- Basilar skull fracture
- High level facial fractures (Le Fort II or III)
- Seatbelt injury above the collar bone (clavicle)
- Cervical bruit/thrill
Testing for Vertebral Artery Injury
If your doctor suspects you might have damaged a brain artery, they will likely recommend a CT angiography (CTA). This test uses special x-ray equipment to provide a detailed view of blood vessels in your brain and is the first choice because it’s reliable, non-invasive, and almost 100% sensitive (meaning it can accurately detect injuries). This test is recommended particularly for those who meet certain criteria known as the modified Denver Screening Criteria.
Though another test called Digital subtraction arteriography (DSA) is known to be the gold standard, it is more invasive, not as widely available, and requires more contrast (a type of dye that makes blood vessels visible on the scan). DSA also comes with a slightly increased risk of stroke. It’s usually the preferred choice when other tests are inconclusive, not available, or when the doctors are considering a type of treatment called endovascular therapy.
On the other hand, if the injury is suspected in the spinal cord or vertebrae, an MRI is usually recommended. An MRI uses powerful magnets and radio waves to create detailed images of the body’s internal structures.
While Magnetic Resonance Angiography (MRA) is another technique to look at blood vessels, it may be less precise or equivalent to a CTA for spotting vertebral artery injury. What’s more, its use can be impractical or unavailable in emergency scenarios, and it’s not used by itself to check for blunt cerebrovascular injury (injury caused by physical impact).
Although an ultrasound can also image blood vessels, it’s not the most suitable to assess vertebral artery injuries because it’s not very sensitive to such injuries. Also, certain parts of the body’s anatomy, such as bones, can hinder visibility.
In younger patients who have experienced an acute ischemic stroke (a stroke caused by a blockage in a blood vessel supplying blood to the brain), spontaneous cerebral artery dissection (a tear in the inner layer of an artery in the brain) should be considered as a possible cause. If this is suspected, a CTA may be performed following a non-contrast head CT (a scan that doesn’t use a contrast dye).
Treatment Options for Vertebral Artery Injury
If you have an acute ischemic stroke, which is a stroke caused by sudden deprivation of blood supply to a part of the brain, arising from vertebral artery dissection, you may be considered for a treatment called systemic thrombolytic therapy if you arrive at the hospital within 3 hours from when your symptoms began. Vertebral artery dissection refers to a tear in the inner lining of the vertebral artery, which is located in the neck and is responsible for supplying blood to the brain.
Systemic thrombolytic therapy is a treatment where a drug such as recombinant tissue plasminogen activator (a protein that breaks down blood clots) is introduced into your body’s blood circulation system to help dissolve the clot and restore blood flow in your brain.
If you arrive at the hospital up to 4.5 hours from when your symptoms began or are unfit for systemic thrombolytic therapy for other reasons, catheter-directed thrombolysis may be considered. In this procedure, a catheter (a thin, flexible tube) is guided to the site of your blood clot and medication is delivered directly to dissolve it.
If thrombolytic therapy is not suitable, options could include anticoagulation (medications to prevent blood clotting), antiplatelet therapy (medications to prevent blood cells from sticking together), or surgical procedures that are either endovascular (mending the artery from within the blood vessel) or open (traditional surgery).
Whether to use anticoagulation or antiplatelet therapy depends on your risk of bleeding, where your injury is located, and its severity. Specialized treatments like endovascular therapy and operative repair are typically reserved for those patients with severe injuries and those who can’t take anticoagulation or antiplatelet therapy due to high risk of complications.
Currently, ways to reduce the risk of future strokes or repeats of the vertebral artery dissection are not conclusive. However, it’s generally recommended that people who have experienced these conditions avoid activities that involve aggressive neck movements, like contact sports or vigorous neck massages. It’s also beneficial to keep high blood pressure well-controlled and to avoid medications containing estrogen.
What else can Vertebral Artery Injury be?
When a patient presents with certain symptoms, a doctor may consider checking for the following health conditions:
- Evaluation for a neck bone fracture
- Neck strain
- Emergency treatment for a specific type of brain bleeding incident
- Migraine headache
- Bleeding stroke
- Tension headache
- Inflammation of blood vessels affecting the main arteries supplying blood to the back of the brain
- Disease caused by a blood clot blocking one of the main arteries in the neck or brain
What to expect with Vertebral Artery Injury
Damage to the vertebral artery from trauma can lead to severe complications. A study by Sanelli and colleagues found a 24% stroke rate and an 8% death rate among patients with this type of injury. This rate was found to be even higher (nearly 40%) for people who also had an injury to their neck spine. The death rate was highest for those with both arteries injured or injuries due to sudden, high-speed trauma such as explosions or gunshot wounds.
The future health condition of patients with unplanned tears in their vertebral artery significantly depends on the location of the tear and the severity of any accompanying stroke or bleeding in the brain. For patients with tears outside the brain, a great outcome is reported in as many as 85% of cases, but between 5% and 25% may end up with a poor neurological condition or death. A poor health result is more common in older patients, cases where the artery is blocked and when stroke severity at diagnosis is high.
