A stroke occurs when blood flow to a part of the brain is interrupted, preventing brain tissue from receiving necessary oxygen and nutrients. This interruption causes the rapid death of brain cells and sudden neurological symptoms. While extremely uncommon, certain types of manual manipulation of the neck have been associated with an increased risk of stroke.
The Primary Mechanism: Arterial Dissection
The most common event linking external force from manipulation to a stroke is an arterial dissection, which involves a tear in the inner lining of an artery wall. This injury often occurs in arteries that may already be weakened or predisposed to damage. The mechanical stress applied during certain movements can exceed the artery’s structural integrity, initiating the tear.
Once the innermost layer of the artery, known as the intima, is damaged, blood can seep in between the layers of the vessel wall. This pooling of blood within the wall itself is the dissection. As blood accumulates, it can sometimes form a clot, or thrombus, at the site of the injury.
This clot poses a significant danger because pieces of it can break off and travel upstream through the bloodstream toward the brain. A traveling clot fragment is called an embolus. If this embolus lodges in a smaller artery within the brain, it blocks the flow of blood, resulting in an ischemic stroke.
The external force, whether from a deep massage technique or a rapid adjustment, often acts as the trigger on an artery that is already vulnerable due to underlying conditions. The resulting clot formation and subsequent blockage in the brain is the direct cause of the stroke symptoms.
High-Risk Anatomical Areas
The neck is the primary anatomical area of concern because it houses the major blood vessels that supply the brain, which are subject to movement and compression. Two pairs of arteries are particularly vulnerable to dissection during deep tissue work, stretching, or extreme rotation of the head.
Carotid Arteries
The Carotid arteries run up the front of the neck, supplying blood to the anterior portion of the brain. Because they are relatively superficial, deep pressure applied directly to the front or sides of the neck can potentially compromise their structure.
Vertebral Arteries
The Vertebral arteries travel through small bony tunnels in the cervical vertebrae, supplying blood to the posterior portion of the brain. They are susceptible to injury during movements involving extreme extension or rapid rotation of the neck. These motions can stretch or compress the vessels within their bony canals. The vulnerability of these vessels highlights the need for careful technique in the cervical spine area.
Client and Practitioner Safety Measures
Mitigating the risk of arterial dissection requires a collaborative approach between the client and the practitioner, starting with a comprehensive health history review.
Client Responsibilities
Clients should always disclose their full medical history, including any recent neck trauma, unexplained headaches, or pre-existing cardiovascular issues that might affect blood clotting. Reporting subtle symptoms immediately during a session is also important, such as dizziness, nausea, or a feeling of “pins and needles.”
Practitioner Responsibilities
For practitioners, a thorough intake form is the first line of defense, ensuring all contraindications are identified before any physical work begins. This process should include asking about symptoms that could indicate an existing, undiagnosed dissection, such as sudden onset of a severe headache or neck pain.
Practitioners must avoid aggressive manipulation techniques, especially those that involve extreme end-range rotation or hyperextension of the client’s neck. Techniques involving direct, deep, sustained pressure near the path of the carotid arteries should be approached with caution or avoided entirely.
Recognizing “red flag” symptoms is a professional responsibility that requires immediate action. If a client exhibits signs of a neurological event, such as sudden and severe dizziness, vision changes, or difficulty speaking, the session must be stopped immediately. These symptoms necessitate a prompt referral for emergency medical evaluation.