Vertebral artery test

Vertebral Artery Test

The Vertebral Artery Test (VAT) is a clinical maneuver used to assess the patency and functionality of the vertebral artery. This artery is a crucial component of the vertebrobasilar system, supplying blood to a significant portion of the brainstem, cerebellum, and the posterior part of the brain. The test is primarily utilized within the fields of physical therapy, chiropractic, and orthopedics to identify the potential for vertebrobasilar insufficiency (VBI) before manipulation or mobilization of the cervical spine.

Procedure

The VAT is performed with the patient in a supine or sitting position. The practitioner passively extends and laterally rotates the patient's head to the side being tested. This position may compress the vertebral artery on that side, potentially reducing blood flow. The patient is observed for signs of vertebrobasilar insufficiency, such as dizziness, nausea, nystagmus, diplopia, or syncope. The test is considered positive if any of these symptoms are elicited, indicating a potential compromise of the vertebral artery's integrity or blood flow.

Indications

The test is indicated for patients who present with symptoms suggestive of cervicogenic dizziness, or when cervical spine manipulation is considered, especially in the upper cervical region. It helps to identify individuals at risk of adverse events due to vertebral artery compromise.

Contraindications

Absolute contraindications include a known history of vertebral artery dissection or significant vertebrobasilar insufficiency. Relative contraindications may include recent trauma to the cervical spine, known cervical artery dissection, or hypermobility syndromes.

Limitations

The sensitivity and specificity of the VAT have been questioned. False positives can occur, and the test does not reliably predict the risk of adverse events during cervical manipulation. Additionally, the test itself may pose a risk to patients with undiagnosed vertebral artery pathology.

Clinical Significance

Despite its limitations, the VAT remains a widely used screening tool in clinical practice. It underscores the importance of a thorough vascular assessment as part of the examination of patients with neck pain or dizziness, particularly when cervical manipulative therapy is being considered.

See Also

• Cervical vertebrae
• Cervical manipulation
• Vertebrobasilar insufficiency
• Dizziness
• Nystagmus