Vascular Flow Limitation of the Cervical Spine

The neck is a complex area where vascular issues can have significant implications for our practice. While we often focus on musculoskeletal aspects, a deep understanding of the vascular system is crucial for ensuring the safety of our patients.

Serious Adverse Events (SAEs)

A systematic study conducted by Leung et al. in 2025 revealed more than 334 serious adverse events linked to neck interventions performed by various professions (physiotherapists, chiropractors, osteopaths). These events were mainly associated with vascular issues, particularly vertebral artery dissections. However, other less common events, such as neurological problems, cerebrospinal fluid leaks, or retinal detachments, were also reported.

While cervical manipulations are often linked to these SAEs, other interventions—such as vestibular tests, gentle mobilizations, or even massages—have also been associated with these events. Establishing a clear cause-and-effect relationship between a neck intervention and a serious adverse event, including vascular ones, remains challenging.

Demystifying the Terminology and Vascular Anatomy of the Neck

The term “vascular pathology of the neck” can be misleading. A more accurate term is “vascular flow limitation,” which is better understood within the medical community. Not all limitations in blood flow leading to ischemia are necessarily linked to observable arterial pathology. The absence of arterial pathology does not necessarily mean there is no flow problem.

Conditions like subclavian steal syndrome or bow-hunter syndrome, which involve dynamic mechanical compression, can also lead to circulation issues without a direct link to neck vessel pathology.

Dissections of the internal carotid artery are reported three to five times more frequently than vertebral artery dissections. This means that, while the vertebral artery is often our primary focus, it is essential to also consider the internal carotid artery when evaluating vascular flow in the neck.

Understanding Cerebral Vascularization and Symptoms

The brain receives its blood supply primarily from two systems:

• anterior system (80% of blood flow): the internal carotid arteries, supplying the brain and retina;
• posterior system (20% of blood flow): the vertebral arteries, supplying the brainstem, cerebellum, and posterior cortex.

This distinction is crucial for understanding potential ischemic symptoms and signs.

Signs and Symptoms of Dissection: What to Look For

Spontaneous dissections, whether they involve the vertebral artery or the internal carotid artery, often begin with neck pain and headaches. These symptoms precede ischemic signs by days to weeks. Patients may experience neck pain and headaches for some time before neurological symptoms develop.

Red flag: neck pain associated with an acute and unusual headache is a key indicator, especially if described as “a headache never felt before.” If this combination occurs, it is highly predictive of the onset of ischemic events.

Symptoms can include:

• internal carotid artery dissection (ICAD): this may manifest as peripheral neurological dysfunction (ptosis, facial paralysis, dysphagia, aphasia, etc.), with ischemic signs like limb weakness or speech difficulties;
• vertebral artery dissection (VAD): ischemic signs are often more frequent (80%) and can include dizziness, falls, ataxia, visual disturbances, etc.

These symptoms are often vague and transient in the early stages, making them difficult to diagnose.

Risk Factors and “Trauma”

The etiology of vascular pathology in the neck is multifactorial. Cervical artery dissections are mainly linked to recent trauma or arterial abnormalities.

Risk factors include:

• sports activities involving sudden head movements;
• intense efforts like the Valsalva maneuver or heavy weightlifting;
• prolonged neck hyperextension.

These events can cause trauma leading to dissections.

Clinical Evaluation: Tools and Precautions

When performing clinical evaluation, it is crucial to raise the suspicion index regarding a vascular profile. Here are some key points to consider:

• most common age for spontaneous dissections: 40 to 55 years;
• symptoms to monitor: acute and unusual pain, appearance of new headaches, multiple neurological symptoms, or recent trauma.

Clinical protocol: if three or four of these criteria are present, the patient should be referred for imaging. If fewer than three, consider an alternative diagnosis, but always provide a “safety net” by informing the patient about what to monitor (e.g., rapid worsening of symptoms, new neurological signs).

When to Refer?—Further Investigations

The higher the suspicion of a vascular pathology, the more important it is to refer the patient for further investigations. Diagnostic tools may include:

• duplex ultrasound;
• MRI or angiography (MRI-A being the gold standard);
• CT scan.

Clinical judgment remains essential, as there are no validated screening tools for an initial reliable exam.

In summary, it is crucial for us, physiotherapists, to adopt a systematic and comprehensive approach to the vascularization of the neck. Do not limit your focus to the vertebral artery but also assess the internal carotid artery. Be vigilant for early signs such as unusual neck pain and headaches, and consider risk factors like trauma or intense exertion. Proper training and heightened vigilance during clinical examination are essential for ensuring patient safety.

For more information and detailed explanations, as well as video demonstrations, we invite you to check out the complete Masterclass on Fullphysio. This content is only a summary of the original video.