Chiropractic is one of the safest, drug-free, non-invasive therapies for treatment of headache, and neck and back pain. Even though chiropractic treatment has an excellent safety record, all health treatments in health care have potential adverse effects. This includes over-the-counter medicines which carry a certain amount of risk.
Many patients experience immediate relief following an adjustment, however, some may experience side effects such as temporary pain, stiffness, slight swelling, temporary dizziness, local numbness, or radiating pain. However, adverse effects from spinal adjustments are typically minor and short-lived.
Safety of Neck Adjustment: The Most Recent Research
Chiropractic adjustment is a precision treatment, typically applied by hand, to the joints of the neck. Neck adjustment improves joint mobility in the neck, restoring the joint's range of motion and reducing muscle spasm. The typical patient notices a reduction of pain, soreness, stiffness and regains improved mobility.
Adjustment of the neck, particularly of the top two vertebrae of the spine, has a rare association with stroke and stroke-like symptoms. The risk is considerably lower than serious adverse events associated with many common health treatments. Treatments such as long-term use of non-prescription pain relievers (aspirin, acetaminophen, ibuprofen) or even birth control pills. Estimates of risk vary but a range of one to two events per million neck adjustments is the ratio generally accepted by the research community.
The February 2002 issue of the Annals of Internal Medicine, which is the journal of the American College of Physicians, reviewed more than 160 reports and studies on chiropractic. It states the following with regard to the safety of neck adjustment: “The apparent rarity of these accidental events has made it difficult to assess the magnitude of the complication risk. No serious complication has been noted in more than 73 controlled clinical trials or in any prospectively evaluated case series to date."
A Canadian study, published in 2001 in the medical journal Stroke, also concluded that stroke associated with neck adjustment is so rare that it is difficult to calculate an accurate risk ratio. The study was conducted by the Institute for Clinical Evaluative Sciences (ICES) and the authors stated: “The evidence to date indicates that the risk associated with chiropractic manipulation of the neck is both small and inaccurately estimated. The estimated level of risk is smaller than that associated with many commonly used diagnostic tests or prescription drugs.”
Research into the association between neck adjustment and stroke has studied what strain, if any, neck adjustment may place on the vertebral arteries. The preliminary findings indicate that neck adjustment is done well within the normal range of motion and that neck adjustment is “very unlikely to mechanically disrupt the vertebral artery.”
There are many risk factors for stroke. These include blood clotting problems, hypertension, smoking, high cholesterol, birth control pills, heart problems and trauma such as blows to the head from car accidents, sports injuries or falls. Some strokes happen spontaneously with no obvious cause during activities of daily living such as backing up a car.
Prior to starting treatment, chiropractors obtain informed consent to treatment from their patients. The patients must receive information to assist them in making their health care choices, and in balancing the relative risks of treatment options with the benefits from that treatment.
Chiropractic researchers are involved in studying the benefits and risks of spinal adjustment in the treatment of neck and back pain through clinical trials, literature reviews and publishing papers reviewing the risks and complications of neck adjustment. The World Health Organization’s Bone and Joint Decade Task Force on Neck Pain and Its Associated Disorders is an international, multi-disciplinary, multi-centre study in which the Canadian chiropractic profession is a partner. One of the Task Force studies is focused specifically on the safety of neck adjustment. This is one example of the ongoing research that will ensure that care is provided as effectively and safely as possible.