Chiropractic care is a widely utilized treatment for musculoskeletal issues, particularly neck and back pain. The practice involves manual therapy, including spinal adjustments and manipulation, to restore mobility and function. Concerns about safety exist, particularly regarding the high-velocity, low-amplitude thrusts sometimes used in the cervical (neck) region. Understanding the potential for severe adverse events, including fatalities, requires a careful examination of the available scientific data.
Statistical Reality of Fatalities
The precise number of fatalities occurring annually due to chiropractic manipulation is not definitively tracked, leading to a significant range in published estimates. Systematic reviews have documented a small number of deaths associated with spinal manipulation, primarily involving the neck. For example, one review noted 26 fatalities published between 1934 and 2009, with vascular accident being the most frequent pathology. Another analysis covering 1975 to 2007 found 26 deaths associated with chiropractic care in the United States.
When considering the volume of treatments performed, these events are statistically rare. The risk of a fatality from a stroke caused by neck manipulation is estimated at approximately one death per four million manipulations. Other risk assessments estimate the rate of a severe adverse event, such as a stroke, to be between one-half and two incidents per one million cervical manipulations. These figures underscore that, while the risk is real, it remains exceptionally uncommon in the context of the millions of adjustments delivered globally. While the total number of annual deaths is not confirmed, summary estimates have suggested perhaps a dozen such deaths may occur in the United States each year, though this figure is highly disputed.
Primary Mechanisms of Severe Injury
The rare, life-threatening complications associated with neck manipulation are overwhelmingly linked to a condition known as vertebral artery dissection (VAD). This event involves a small tear in the inner lining of one of the vertebral arteries, which travel up the neck to supply blood to the brain. Specifically, the vertebral arteries pass through small bony canals in the cervical vertebrae, making them vulnerable to stretching or injury from extreme movements.
A forceful, high-velocity rotation of the neck, a technique sometimes used in manipulation, is theorized to traumatize the arterial wall. Once a tear occurs, blood can enter the wall layers, causing the artery to balloon or a blood clot to form. Pieces of this clot can then break off and travel to the brain, blocking blood flow and causing an ischemic stroke.
The resulting restriction of blood flow to the brain, known as a vertebrobasilar accident, is the direct cause of neurological injury and subsequent death in the most severe cases. Dissection can also happen spontaneously, often due to an underlying vulnerability in the patient’s connective tissue, making it difficult to isolate the manipulation as the sole cause.
Challenges in Tracking and Reporting Deaths
Obtaining precise annual statistics on fatalities from chiropractic care is complicated by several interconnected factors. A primary issue is the difficulty in establishing a clear causal link between the manipulation and the adverse event. Patients seeking chiropractic treatment for neck pain or headaches may already be experiencing the early symptoms of an impending vertebral artery dissection.
This situation creates a “chicken or the egg” dilemma, where it is often impossible to determine if the manipulation caused the dissection or if the patient’s pre-existing, symptomatic dissection was simply exacerbated by the treatment. Population-based studies have even suggested that the risk of VAD is similar for patients who visit a chiropractor compared to those who visit a primary care physician for neck pain, supporting the theory that the event may have been spontaneous or already underway.
Furthermore, there is no mandatory, centralized reporting system for adverse events related to chiropractic care. Data collection relies heavily on voluntary reporting, systematic reviews of medical case reports, and legal findings, all of which are subject to significant underreporting. The most severe cases are the ones most likely to be published in medical literature or reported publicly, potentially leading to a disproportionate representation of fatal outcomes in the available data.
Risk Context and Comparison
To provide perspective on the rarity of fatal outcomes from neck manipulation, it is helpful to compare the risk to other common activities and medical interventions. The estimated risk of death from chiropractic-related stroke, conservatively placed at about one per four million manipulations, is exceedingly low. For comparison, the annual rate of spontaneous vertebral artery dissection—those unrelated to any trauma—is estimated to be much higher, occurring at a rate of 2.5 to 3 cases per 100,000 people.
Risks associated with common medications are also substantially higher. For instance, the use of over-the-counter Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) for conditions like musculoskeletal pain carries a much greater quantifiable risk. NSAID-induced gastrointestinal bleeding results in an estimated annual mortality rate of four per 10,000 users, leading to thousands of deaths each year in the United States.
When considering the risk of a catastrophic event, the probability is often cited as being lower than that associated with consulting a primary medical physician. This context helps illustrate that while the rare adverse event is serious, the risk level is minute compared to many other quantifiable daily and medical hazards.