There is evidence to indicate that upper cervical manipulation can cause stroke by injuring vertebrobasilar arteries. Many chiropractors routinely manipulate the neck as part of a treatment regimen designed to improve health by adjusting “vertebral subluxations.” Physical therapy practitioners may occasionally use cervical spine manipulation in the treatment of a problem related to loss of mobility. Although stroke caused by neck manipulation is rare, it happens most often among chiropractic patients who may be subjected to unnecessary manipulation based upon untenable guidelines. This review by a retired chiropractor offers some insight into problems associated with chiropractic neck manipulation.
Widespread concern about cervical manipulation as a cause of vertebral artery dissection and stroke began in 1996 when a review by the RAND research organization on the literature on cervical spine manipulation and mobilization concluded that the incidence of stroke and other serious complications was about 1.46 per million manipulations. The report also noted that only about 11.1 percent of reported indications for cervical spine manipulation were appropriate.1 In the same year, the National Chiropractic Mutual Insurance Company (NCMIC) published a manual that stated: “It has to be accepted that VBS [vertebrobasilar stroke] following SMT [spinal manipulative therapy] does occur. The temporal relationship, between young healthy patients without osseous or vascular disease attending a SMT practitioner, then suffering these rare strokes is so well documented.”2
Since most neck manipulation is done by chiropractors treating a variety of health problems as “primary care physicians,” neck manipulation is more problematic among chiropractors than among more specialized physical therapists.
Estimates on the incidence of stroke caused by cervical spine manipulation range from 1 in 400,000 to 1 in 5.8 million manipulations, depending upon who is doing the survey. A chiropractor-authored review of malpractice data provided by the Canadian Chiropractic Protective Association, for example, concluded that “a chiropractor will be made aware of an arterial dissection” only once per 5.85 million cervical manipulations.3 This stroke-manipulation ratio is widely quoted by chiropractors, despite the fact that court-litigated cases do not reflect the total number of manipulation-related strokes, most of which are unreported or undetected.
Further backing away from observations that neck manipulation is a cause of stroke, a 2006 report published by NCMIC Chiropractic Solutions concluded: “The incidence of stroke in the population as a whole is no different (2 per 100,000 persons annually) than among those who received manipulation treatment of the neck,” adding that “The best scientific evidence available has shown no causative relationship between appropriately applied spinal manipulation and stroke events.”4
Many studies have linked chiropractic upper neck manipulation with stroke.5,6 Recent reports produced by chiropractors, however, argue that the incidence of stroke among persons who have had neck manipulation is “...to the same order of magnitude as that occurring in the general population,”4 and that there is “. . . no evidence of excess risk of VBA [vertebral artery] stroke associated with chiropractic care compared with primary care.”7 But these reports fail to distinguish strokes caused by trauma to the vertebral arteries of young healthy people from the type of strokes that occur among predisposed persons, especially the elderly. No consideration is given to the possibility that many strokes caused by neck manipulation may go unreported. When patients seek medical care for paralytic symptoms caused by release of a blood clot that was formed days or weeks earlier by neck manipulation, a connection between neck manipulation and stroke may not be made. Such strokes may then be reported by primary care physicians who are unaware of preceding trauma caused by neck manipulation.
The most recent chiropractor-headed study of the association between chiropractic visits and vertebrobasilar artery stroke, based on billing records, concluded that strokes associated with chiropractic neck manipulation occur because patients with headache and neck pain caused by vertebrobasilar dissection seek chiropractic care for relief of symptoms: “The increased risks [sic] of VBA stroke associated with chiropractic and PCP [primary care physician] visits is likely due to patients with headache and neck pain from VBA dissection seeking care before their stroke.”7 In other words, the report implies that a chiropractor is not to be blamed for making an incorrect diagnosis and then manipulating the neck of a patient who presents the symptoms of a stroke in progress. It goes without saying, however, that it is the responsibility of the chiropractor to recognize symptoms of stroke before manipulating the patient’s neck, especially if the chiropractor practices independently or portrays himself or herself as a primary care physician. But you cannot depend upon the diagnostic acumen of a chiropractor who believes that he can improve health by adjusting the spine. Physicians and therapists who refer patients to chiropractors must be cautious in selecting patients for referral, and they must take responsibility for the diagnosis when making such referrals.
Clearly, patients with acute head and neck pain that might be the result of stroke or arterial dissection should not have their necks manipulated. Elderly persons who might be susceptible to stroke because of diseased vertebral arteries should not be subjected to the risk of neck manipulation. The fact that spontaneous vertebral artery dissection can occur in susceptible persons of all ages does not excuse neck manipulation as a cause of traumatic dissection but rather underscores another reason for avoiding such treatment whenever possible.
It is enough to know that strokes occurring among healthy young people immediately following neck manipulation are likely to be the result of trauma to vertebral arteries. And it is enough to know that strokes associated with neck manipulation are often the result of unnecessary treatment. Persons undergoing chiropractic neck manipulation “to maintain health,” for example, have developed symptoms of stroke while still lying on the treatment table.8 Such observations alone are enough to question use of neck manipulation by chiropractors. Every patient should be required to read and sign an informed consent sheet revealing the risk associated with neck manipulation before submitting to such treatment by any kind of practitioner, even when referred by a physician.
Indications for Neck Manipulation
Manipulation of the upper cervical spine should be reserved for carefully selected musculoskeletal problems that do not respond to such simple measures as time, massage, exercise, mobilization, longitudinal traction, or over-the-counter medication. Because of the tortuous route of the vertebral arteries where they exit the skull to thread through the transverse processes of the first and second cervical vertebrae, head and neck rotation forced by manual manipulation should not exceed 45 or 50 degrees if kinking or traumatic dissection of these arteries is to be avoided.9,5 Rotating the head to rotate the cervical spine would force excessive rotation in the occiput-atlas-axis area where the vertebral arteries are most vulnerable. Rapid manual rotation of the head might also cause damage by overcoming the arteries’ normal elasticity, causing tears and blood clots in the intimal lining of the vertebrobasilar arteries. The slow stretching of mobilization within a normal range of movement may be less damaging to arteries than the rapid movement required to rotate the cervical spine beyond its normal range of motion or to move joints into the paraphysiologic space to produce cavitation.
It seems likely that in rare cases where there is significant discomfort or loss of mobility caused by binding or fixation of a vertebral joint or by entrapment of a synovial membrane or a cartilaginous fragment, manipulation might be the treatment of choice. There is evidence to indicate that cervical spine manipulation and/or mobilization may provide short-term pain relief and range of motion enhancement for persons with subacute or chronic neck pain.1 There is no credible evidence, however, to indicate that neck manipulation is any more effective for relieving mechanical neck disorders than a number of other physical treatment modalities,10 and it is clear that adverse reactions are more likely to occur following manipulation than mobilization.11 When manipulation is performed, a joint is moved farther than normally possible in an active movement. Passive mobilization moves a joint through its normal range of motion. Cervical spine manipulation may force excessive movement and worsen symptoms related to cervical disc herniation or spondylosis, producing such complications as radiculopathy or myelopathy.12 At least one study has suggested that manual therapy in the form of mobilization is more effective and less costly for treating neck pain than physiotherapy or care by a general practitioner.13 There is certainly no justification for routine use of cervical manipulation as a treatment for general health problems.
All things considered, manual rotation of the cervical spine beyond its normal range of movement is rarely justified. The neck should never be manipulated to correct an asymptomatic “chiropractic subluxation” or an undetectable “vertebral subluxation complex” for the alleged purpose of restoring or maintaining health or to relieve symptoms not located or originating in the neck. There is no evidence that such subluxations exist. When a painful, actual subluxation (partial dislocation) occurs, manipulation might occasionally be helpful but is most often contraindicated.14
Although there might be an occasional need for appropriate, properly controlled neck manipulation in the treatment of an uncomplicated musculoskeletal problem that results in loss of mobility, there is no justification for the use of such treatment based on the chiropractic vertebral subluxation doctrine. Consultation with an orthopedist or a neurologist should be part of a consensus that determines the need for neck manipulation, weighing benefit against risk. Persons with certain structural or vascular abnormalities, or who might be taking anti-coagulants or other medications that would increase risk of bleeding, would be advised not to undergo neck manipulation for any reason.
When a sudden onset of neck pain occurs, it is absolutely essential that an attempt be made to rule out a pre-existing vertebral artery dissection before neck manipulation is done, lest manipulation releases an embolus that will travel to the brain. Sudden, severe headache might also be an indication that stroke is occurring or is about to occur. Neck manipulation should not be considered until a neurologist has tested the patient for symptoms of stroke. Such a careful approach would be problematic among chiropractors who base diagnosis and treatment upon detection and correction of a “vertebral subluxation complex.”15
Neck Manipulation a Measure of Last Resort
Because it may be difficult or impossible to determine beforehand who might have weak or diseased vertebral arteries, or who might be vulnerable to vertebral artery dissection or stroke that could be caused or aggravated by upper neck manipulation, rotational neck manipulation should be a measure of last resort. A physical therapist who is trained in the use of both manipulation and mobilization for musculoskeletal problems would be less likely to use manipulation inappropriately than a chiropractor who routinely “adjusts the spine to restore or maintain health.”
According to the Association of Chiropractic Colleges (ACC), “Chiropractic is concerned with the preservation and restoration of health, and focuses particular attention on the subluxation. A subluxation is a complex of functional and/or structural and/or pathological articular changes that compromise neural integrity and may influence organ system function and general health.”16 Chiropractors who are guided by this vague paradigm (which is more of a belief than a theory) often manipulate the full spine of every patient for “subluxation correction.” Few chiropractors specialize in the care of back pain and other musculoskeletal problems, and only a few of them have renounced the chiropractic vertebral subluxation doctrine.17
There are many chiropractors who claim to be able to improve health and relieve neck pain or headache by tapping on “subluxated” cervical vertebrae with a spring-loaded stylus, thus avoiding dangerous rotation of the neck—a safe, but ineffective treatment. Some of these chiropractors believe that misalignment of the atlas is the cause of a variety of unrelated ailments, including low-back pain. Nearly 26 percent of chiropractors subscribe to this “Palmer upper cervical” belief.16 Most vertebral artery injuries occur at the level of the atlantoaxial joint where there is no intervertebral disc and where the greatest amount of rotation takes place. For this reason, chiropractic upper cervical manipulation “to restore and maintain health” is dangerous as well as unnecessary and cannot be compared with generic manipulation used in the treatment of mechanical-type neck or back pain.
Using Manipulation Appropriately
While physical therapists, physiatrists, osteopaths, and orthopedists sometimes manipulate the neck for a carefully selected musculoskeletal problem, chiropractors who are guided by the ACC’s subluxation paradigm may routinely manipulate the neck, thus subjecting the patient to unnecessary risk.18 Whatever the incidence of stroke per number of neck manipulations might be, this risk is greater per patient among chiropractic patients who may be manipulated many times for “health reasons” and who may be manipulated regularly for “maintenance care.”
Chiropractors who renounce vertebral subluxation dogma and specialize in the care of back pain will use manipulation more appropriately. Unfortunately, there is no official or legal definition limiting chiropractors to treatment of musculoskeletal problems, making it difficult to find a properly limited chiropractor.19
Forty-two states permit direct access to the services of physical therapists, some of whom may include use of manipulation among their treatment modalities. A physical therapist who offers neck manipulation without requiring a physician’s prescription must be prepared to take responsibility for the diagnosis and the treatment outcome. Because of the dangers associated with neck manipulation, therapists who perform such manipulation should work closely with medical specialists to determine if benefit outweighs risk, and then have the patient sign an informed consent sheet prior to manipulation.
References
- Coulter ID, Hurwitz EL, Adams AH, et al. The Appropriateness of Manipulation and Mobilization of the Cervical Spine. Santa Monica, CA; RAND; 1996.
- Terrett AGT. Vertebrobasilar Stroke Following Manipulation. West Des Moines, IA: National Chiropractic Mutual Insurance Company; 1996.
- Haldeman S, Carey P, Townsend M, Papadopoulos C. Arterial dissections following cervical manipulation: the chiropractic experience. Can Med Assoc J 2001;165(7):905–6.
- Triano J, Kawchuk G. Current Concepts in Spinal Manipulation and Cervical Arterial Incidents. Clive, IA: NCMIC Chiropractic Solutions; 2006.
- Terrett AGT. Current Concepts in Vertebrobasilar Complications Following Spinal Manipulation. West Des Moines. IA: NCMIC Chiropractic Solutions; 2001.
- Ernst E. Adverse effects of spinal manipulation: a systematic review. J R Soc Med 2007;100:06-0100.1-9.
- Cassidy JD, Boyle E, Cote P, et al. Risk of vertebrobasilar stroke and chiropractic care: results of a population-based case-control and case-crossover study. Spine 2008;33(No. 4S):S176–83.
- Hall H. Chiropractic stroke again! A landmark lawsuit in Canada. Science-Based Medicine. 2008. Available at http://www.sciencebasedmedicine.org?p=152. Accessed October 22, 2008.
- Magee D. Orthopedic Physical Assessment. Philadelphia, PA: W.B. Saunders Company; 1987.
- Gross AR, Hoving JL, Haines TA, et al. Manipulation and mobilization for mechanical neck disorders. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No: CD004249.DOI: 10.1002/14651858.CD004249.pub2.
- Hurwitz EL, Morgenstern H, Vassilaki M, et al. Frequency and clinical prediction of adverse reactions to chiropractic care in the UCLA neck pain study. Spine 2005;30(13):1477–84.
- Malone DG, Baldwin NG, Tomecek FJ, et al. Complications of cervical spine manipulation therapy: 5-year retrospective study in a single-group practice. Neurosurg Focus 2002;13(6):1–7.
- Korthals-de Bos, Ingeborg BC, Hoving Jan L, et al. Cost effectiveness of physiotherapy, manual therapy, and general practitioner care for neck pain: economic evaluation alongside a randomised controlled trial. Br Med J April 26, 2003.
- Homola S. Chiropractic: history and overview of theories and methods. Clin Orthop Relat Res 2006;Number 444:236–42.
- Homola S. Can chiropractors and evidence-based manual therapists work together? An opinion from a veteran chiropractor. J Man Manipulative Ther 2006;14(2):E14-E18. Available at http://jmmtonline.com/documents/HomolaV14N2E.pdf. Accessed November 10, 2008.
- Christensen MG, Kollasch MW, Ward R, et al. Job Analysis of Chiropractic. Greeley, CO; National Board of Chiropractic Examiners; 2005.
- National Association for Chiropractic Medicine. Available at http://www.chiromed.org. Accessed November 10, 2008.
- Homola S. Is the chiropractic subluxation theory a threat to public health?” SRAM 2001;3(1):45–53.
- Homola S. Finding a Good Chiropractor. Arch Fam Med 1998;7(Jan/Feb):20–23.
