A vertebral artery occlusion means one of the two arteries running up the back of the neck to the brain has become blocked, usually by fatty plaque or, in younger people, by a tear in its wall. The result can range from no symptoms at all to dizziness, unsteadiness or a stroke in the back of the brain. Because the two arteries join, one can often stand in for the other, which is why a blockage is sometimes found by chance and why the outlook varies so much from person to person. Treatment usually centres on preventing a stroke with medicines, with procedures saved for emergencies or repeated symptoms.
Where the Vertebral Arteries Run and Why a Blockage Matters
Each vertebral artery branches off the artery under the collarbone and climbs through small bony holes in the neck bones, from about the sixth vertebra up to the top of the spine.12018 ASM EPOS. Common Vertebral Artery Variants and their Clinical Implications Inside the skull, the left and right arteries merge into a single basilar artery.22018 ASM EPOS. Common Vertebral Artery Variants and their Clinical Implications Together they supply the brainstem, the balance centre, the back of the brain and part of the spinal cord.32018 ASM EPOS. Common Vertebral Artery Variants and their Clinical Implications Doctors describe the artery in four segments, V1 to V4, from its start in the chest to inside the skull, and your report may name one.4PubMed Central. The segmentation of the vertebral artery: An ambiguous anatomical concept
On a report, a narrowing is called stenosis, while an occlusion means no blood gets through that spot. Many people have one vertebral artery that is naturally larger than the other. A small or underdeveloped artery can look like disease on a scan but is often normal. It matters because the larger side may be doing most of the work, so it is reasonable to ask your doctor whether your blocked side was the dominant one.
A blockage doesn’t always cut off supply. If the other vertebral artery is open and both meet at the basilar artery, blood can flow backwards to fill the blocked side above the blockage.5PubMed Central. Safety of unilateral endovascular occlusion of the cervical segment of the vertebral artery without antecedent balloon test occlusion When both vertebral arteries are blocked or badly narrowed, a small artery along the spinal cord can reverse its flow and become an important backup supply.6American Journal of Neuroradiology. Anterior Spinal Artery as a Collateral Channel in Cases of Bilateral Vertebral Arterial Steno-Occlusive Diseases
A blockage found by chance may have formed slowly, giving backup routes time to open. It still signals artery disease that needs treatment of the risk factors behind it.
What Causes a Vertebral Artery to Block
Fatty plaque build-up is the most common cause of vertebral artery narrowing.7PubMed Central. Vertebral Artery Stenosis: A Narrative Review When blood cholesterol is high, “bad” LDL cholesterol sticks into the artery lining, draws in immune cells and hardens into plaque.8PubMed Central. Vertebral Artery Stenosis: A Narrative Review These plaques often form in the neck portion, especially where the artery begins.9PubMed Central. Vertebral Artery Stenosis: A Narrative Review Among people already treated for artery disease elsewhere, such as in the heart or legs, about 7.6% had a silent narrowing over 50% or a blockage at the vertebral artery.10PubMed Central. Severe Bilateral Vertebral Arterial Disease Masquerading as Vertigo Smoking, high blood pressure, diabetes and high cholesterol raise the risk, as they do for heart disease.
The other main cause is a dissection, a tear in the artery wall. Blood enters the wall and splits its layers, which narrows the artery or makes it balloon out.11PubMed Central. Vertebral Artery Dissection: Natural History, Clinical Features and Therapeutic Considerations Clots that form at the tear and travel upward are the most common way a dissection causes a stroke.12Canadian Journal of Neurological Sciences. Extracranial Carotid and Vertebral Artery Dissection: A Review In children, most back-of-brain strokes follow neck trauma that may be minor or repeated.13Developmental Medicine and Child Neurology. Tethering of the vertebral artery in the congenital arcuate foramen of the atlas vertebra: a possible cause of vertebral artery dissection in children A small extra bony ring on the top neck bone, present in about 3 to 15% of people, may tether the artery and make it easier to tear with neck movement.14Developmental Medicine and Child Neurology. Tethering of the vertebral artery in the congenital arcuate foramen of the atlas vertebra: a possible cause of vertebral artery dissection in children
Tears can follow obvious injuries like car crashes or falls. They can also follow minor strain such as sports, a sudden neck twist or forceful neck manipulation, and many happen with no clear trigger at all. New one-sided neck or back-of-head pain after strain deserves attention.
Rarer causes exist. In bow hunter’s syndrome, turning the head squeezes the artery shut, causing symptoms that pass when the head turns back.15PubMed Central. Rare Etiology of Bow Hunter’s Syndrome and Systematic Review of Literature Fibrous bands or bone at the top of the neck can pinch the artery during rotation.16PubMed Central. Rotational Vertebral Artery Compression: Bow Hunter’s Syndrome
Giant cell arteritis, an inflammation of arteries in older adults, involved the vertebral arteries in about a third of patients with typical ultrasound findings.17PubMed. Vertebral artery involvement in giant cell arteritis: Symptoms, treatment and outcome About 19% of those had a stroke or mini-stroke at diagnosis, more often when the narrowing was severe.18PubMed. Vertebral artery involvement in giant cell arteritis: Symptoms, treatment and outcome It can block both vertebral arteries even without the classic headache.19PubMed Central. Bilateral vertebral artery occlusion without headache in giant cell arteritis It almost only affects people over 50. Scalp tenderness, jaw pain when chewing and vision changes are typical signs, and blood tests for inflammation are often high. It is treated with steroids, which is quite different from plaque treatment.
Symptoms and When to Call an Ambulance
Sudden spinning dizziness can be the only first symptom of a back-of-brain stroke.20PubMed. Vertigo, vertebrobasilar disease, and posterior circulation ischemic stroke Dizziness with trouble standing or walking makes a stroke more likely than an inner-ear problem.21PubMed. Vertigo, vertebrobasilar disease, and posterior circulation ischemic stroke Other warning signs include double vision, slurred speech, trouble swallowing, clumsiness, and numbness or weakness. A mini-stroke, or TIA (transient ischemic attack), causes the same symptoms, but they fade within minutes to hours.
Vertigo from a stroke gets missed because inner-ear causes are far more common. The standard FAST checklist also doesn’t include dizziness or balance. Being unable to walk unaided, a new headache, or any other nerve symptom should raise concern. Tell emergency staff the exact time symptoms began.
A tear in the vertebral artery has its own pattern. People most often had sudden headache or neck pain along with unsteadiness and jerky eye movements.22Ictus. Lateral Medullary Syndrome in Patients with Vertebral Artery Dissection: Case Series Illustration and Review of the Neuroanatomical Correlates Many had loss of pain and temperature feeling on one side of the face and the opposite side of the body.23Ictus. Lateral Medullary Syndrome in Patients with Vertebral Artery Dissection: Case Series Illustration and Review of the Neuroanatomical Correlates Some also had a drooping eyelid and small pupil on one side.24Ictus. Lateral Medullary Syndrome in Patients with Vertebral Artery Dissection: Case Series Illustration and Review of the Neuroanatomical Correlates New severe neck pain with dizziness, numbness or any of the warning signs above needs emergency care, not a massage or chiropractor.
Some symptoms come and go with head position. Dizziness or blurred vision only when turning the head may signal compression. Note which direction and how far you turn, and report it to a doctor rather than ignoring it, since it can be tested with scans while the head is turned.
How Doctors Confirm a Blocked Vertebral Artery
A neck ultrasound is painless and quick, but it misses about 3 in 10 narrowings of the vertebral artery.25PubMed Central. Imaging of vertebral artery stenosis: a systematic review It was correct in about 98% of normal arteries, so when it does show a problem it is usually right.26PubMed Central. Imaging of vertebral artery stenosis: a systematic review At the artery’s starting point, ultrasound spotted about 86% of complete blockages.27PubMed. Ultrasound Criteria for Assessment of Vertebral Artery Origins
The more reliable options are CT angiography (CTA) and MR angiography (MRA), called artery scans below. MR angiography with contrast dye picked up about 94% of narrowings.28PubMed Central. Imaging of vertebral artery stenosis: a systematic review CT angiography, a fast scan with dye injected in a vein, is also accurate and widely used in emergencies.29PubMed Central. Imaging of vertebral artery stenosis: a systematic review A catheter angiogram, where dye is injected through a thin tube from the groin or wrist, is the reference test, often done before a stent or surgery.
Ultrasound reports list blood speed in centimetres per second, which rises where an artery narrows.30PubMed. Color Doppler imaging evaluation of proximal vertebral artery stenosis At the artery’s start, a peak speed of about 140 cm/s or more suggests 50 to 69% narrowing, and about 210 cm/s or more suggests 70 to 99%, though these cut-offs are a guide and are usually confirmed with an artery scan.31PubMed. Color Doppler imaging evaluation of proximal vertebral artery stenosis32PubMed Central. Duplex Ultrasonography for the Evaluation of Extracranial Vertebral Artery: A Prospective Comparison With Digital Subtraction Angiography
A normal ultrasound doesn’t rule everything out. It sees the neck section of the artery best, while the part inside the skull is hard to see. With ongoing symptoms, ask whether an artery scan is planned. Doctors also scan the brain itself to look for stroke damage.
Before a dye scan, tell staff about kidney problems or dye allergies, and mention diabetes medicines such as metformin. Some MRI scans aren’t possible with certain implants.
Emergency Treatment for a Stroke from a Blocked Vertebral Artery
Clot-busting medicine given through a vein is a standard first stroke treatment within hours of onset. Doctors once worried it could worsen bleeding inside a torn artery wall.33PubMed Central. Intravenous thrombolysis for acute ischemic stroke due to vertebral artery dissection: A case report In practice it has worked about as well for neck artery tears as for other strokes, without raising brain bleeding risk.34PubMed Central. Intravenous thrombolysis for acute ischemic stroke due to vertebral artery dissection: A case report It may help less with vertebral tears than carotid ones, because a tear can pinch off tiny branches rather than form a clot.35PubMed Central. Intravenous Thrombolysis in Cervical Artery Dissection–Related Stroke: A Nationwide Study
Doctors can also thread a catheter up to remove a clot or balloon open the artery.36PubMed. Mechanical Thrombectomy for Tandem Vertebrobasilar Stroke: Characteristics and Treatment Outcome For blockages reaching into the basilar artery, the vessel was reopened in about 87 to 96% of procedures.37PubMed Central. Predictors and outcomes of angioplasty and stenting in acute intracranial atherosclerosis-related vertebrobasilar artery occlusion Yet only about a third to half of these patients recovered to living largely independently at 3 months.38PubMed Central. Predictors and outcomes of angioplasty and stenting in acute intracranial atherosclerosis-related vertebrobasilar artery occlusion Even when treated more than 24 hours after onset, catheter treatment led to more good recoveries (58% vs 45%) and fewer deaths (13% vs 28%) than medicines alone.39JAMA Network Open. Outcomes of Endovascular Treatment in Patients With Vertebrobasilar Artery Occlusion Beyond 24 Hours
In the first hours, the team rushes a brain scan and an artery scan, and doctors ask when the person was last seen well. Catheter treatment usually needs transfer to a specialist stroke centre, and severe basilar strokes may need intensive care. Brainstem strokes can affect breathing, swallowing and consciousness, while small strokes in the same area can recover very well.
Long-Term Treatment With Medicines
For plaque, the mainstay is an antiplatelet pill such as aspirin or clopidogrel, a statin, and control of blood pressure and blood sugar. Quitting smoking and exercising regularly lower risk in the same way they protect the heart.
For tears in the artery wall, the two main options are antiplatelet pills or stronger anticoagulants such as warfarin.40PubMed. Antiplatelet treatment compared with anticoagulation treatment for cervical artery dissection (CADISS): a randomised trial In a trial, recurrent stroke at 1 year was about 2.5% and the same with either.41PubMed Central. Antiplatelet Therapy vs Anticoagulation Therapy in Cervical Artery Dissection Pooled studies suggest anticoagulants cut strokes slightly more but roughly double major bleeding.42PubMed. Anticoagulation Versus Antiplatelets in Spontaneous Cervical Artery Dissection: A Systematic Review and Meta-Analysis So the choice is weighed for each person, and many tears heal over months. Follow-up scans check whether the artery has reopened.43PubMed Central. Antiplatelet Therapy vs Anticoagulation Therapy in Cervical Artery Dissection
If you take blood thinners, tell dentists and surgeons. Avoid adding painkillers like ibuprofen without asking, and watch for black stools, unusual bruising or bleeding gums. Never stop them on your own.
After a dissection, doctors usually advise avoiding neck manipulation and heavy straining while it heals. Ask when contact sports and heavy lifting are safe again, and report any new neck pain or symptoms quickly.
Stents and Surgery for a Blocked Vertebral Artery
A stent is a mesh tube placed through a catheter to hold a narrowed artery open. With severe narrowing at the artery’s start, stenting showed a trend toward fewer repeat strokes and mini-strokes over 4 years (10% vs 45%), though this was not proven.44PubMed. Long-term outcome of symptomatic severe ostial vertebral artery stenosis (OVAS) In people with disease in both vertebral arteries the difference was larger: none had repeat events after stenting versus 91% on medicines alone.45PubMed. Long-term outcome of symptomatic severe ostial vertebral artery stenosis (OVAS)
Surgeons can instead reattach the vertebral artery to the carotid artery or use a graft to bypass the blockage.46Journal of Korean Neurosurgical Society. Extracranial Carotid-Vertebral Artery Bypass Technique and Surgical Outcomes Combined death and stroke risk is about 0.9% for repairs low in the neck and about 3% higher up.47Journal of Korean Neurosurgical Society. Extracranial Carotid-Vertebral Artery Bypass Technique and Surgical Outcomes In one series of people still having symptoms despite medicines, all symptoms resolved and none died.48PubMed. Vertebral artery transposition for revascularization of the posterior circulation: a critical assessment of temporary and permanent complications and outcomes For bow hunter’s syndrome, surgery can free the artery from the bone or band compressing it.49PubMed Central. Rotational Vertebral Artery Compression: Bow Hunter’s Syndrome
Before a procedure, ask why medicines alone are not enough in your case and about the centre’s experience with vertebral procedures. Ask about restenosis, the artery narrowing again, and which blood thinners you’ll need afterwards.
A complete blockage is often left alone. Fully closed arteries are harder to reopen safely, and backup routes may already be supplying the brain. Doctors focus instead on protecting the remaining open arteries.
Outlook and Risk of Another Stroke
Among about 280 people with silent narrowing at the artery’s start, only five had a back-of-brain stroke over about 4.6 years.50PubMed Central. Severe Bilateral Vertebral Arterial Disease Masquerading as Vertigo After a stroke, though, people whose narrowing caused symptoms had about a 1.9% yearly risk of a back-of-brain stroke, versus almost none without symptoms.51PubMed Central. Long-term outcome of vertebral artery origin stenosis in patients with acute ischemic stroke For narrowing inside the skull that caused symptoms, repeat strokes ran about 5 to 9 per 100 people each year.52PubMed Central. Stroke Recurrence Rates Among Patients With Symptomatic Intracranial Vertebrobasilar Stenoses: Systematic review and meta-analysis Overall yearly heart and stroke events were about 7%, so heart risk matters as much as the artery itself.53PubMed Central. Long-term outcome of vertebral artery origin stenosis in patients with acute ischemic stroke
Blood pressure, cholesterol, blood sugar and smoking drive both stroke and heart attack. Taking medicines daily matters more than any single procedure, and regular check-ups catch new symptoms early.
Recovering Balance After a Back-of-Brain Stroke
Dizziness and unsteadiness are common after strokes in the back of the brain. Balance and walking improved over 6 weeks with home exercises as much as with clinic-based programs.54PubMed. Vestibular rehabilitation in acute central vestibulopathy: a randomized controlled trial Exercises that retrain the balance system improved walking confidence.55JOURNAL OF CLINICAL AND DIAGNOSTIC RESEARCH. Comparative Study to Evaluate the Effectiveness of Vestibular Rehabilitation Therapy versus Dual Task Training on Balance and Gait in Posterior Cerebral Artery (PCA) Stroke Gaze stability exercises, which mean keeping your eyes on a target while moving your head, improved steadiness when standing.56PubMed. Transient Effects of Gaze Stability Exercises on Postural Stability in Patients With Posterior Circulation Stroke
To make a home program work, get the exercises taught in person by a therapist first. Practise daily near a wall or sturdy chair, and expect dizziness to briefly increase during the exercises. Report falls or new symptoms promptly.