Claims made for the benefits of spinal adjustments range from temporary, palliative (pain relieving) effects to long term wellness and preventive care. Some claims are controversial, particularly with regard to indications and health benefits. There is debate concerning the safety of some of the procedures used in spinal adjustments, particularly those including upper cervical manipulations.
Spinal adjustment is the chiropractic term for a procedure known as spinal manipulation. It is specifically intended to correct vertebral subluxations. Spinal manipulation has documented use as far back as Hippocrates and the ancient Egyptians and was carried through the ages by families of bonesetters. The modern form of spinal manipulation techniques have characteristic biomechanical features, and are usually associated with an audible "popping" sound. There is strong evidence that this sound is the result of a phenomenon known as cavitation. Many adjustment techniques and methods have been developed through the years by chiropractors, not all of which involve HVLA thrust manipulation.
The central clinical method that all chiropractors agree on is spinal manipulation or spinal adjustment. Although the terms "spinal adjustment" and "spinal manipulation" are often used interchangeably by chiropractors in their literature and research, chiropractors much prefer to use the word "adjustment" to describe the nature of their work.
The International Chiropractors Association (ICA) defines a chiropractic adjustment as being “characterized by a specific thrust applied to the vertebra utilizing parts of the vertebra and contiguous structures as levers to directionally correct articular malposition [an undesired positioning of a joint].” The definition of this procedure describes the use of a load (force) to specific body tissues with therapeutic intent. This ‘load’ is traditionally used by hand, and can vary in its velocity, amplitude, duration, frequency, and body location (Meeker & Haldeman, 2002, p. 218), and is usually abbreviated HVLA (high velocity low amplitude) thrust.
The intention of a chiropractic adjustment is to affect or correct the alignment, motion and/or function of a vertebral joint. Specifically, they are intended to correct "vertebral subluxations", the term given to the signs and symptoms that are said by chiropractors to result from abnormal alignment of vertebrae (Meeker & Haldeman, 2002, p. 218). This intention forms the legal and philosophical foundation of the profession, and is even formulated in US Medicare law as "manual manipulation of the spine to correct a subluxation."
As the chiropractic profession engaged in the pursuit of improving health through adjustments to the nervous system, individual practitioners and institutions proposed and developed various proprietary techniques and methods. While many of these techniques did not endure, hundreds of different approaches remain in chiropractic practice today. Not all of them involve HVLA thrust manipulation. Most cite case studies, anecdotal evidence, and patient testimonials as evidence for effectiveness. These techniques include:
There are many techniques which chiropractors can specialize in and employ in spinal adjustments. Some of the most notable techniques include:
The effects of spinal adjustment vary depending on the method performed. All techniques claim effects similar to other manual therapies, ranging from decreased muscle tension to reduced stress. Studies show that most patients go to chiropractors for musculoskeletal problems: 60% with low back pain, and the rest with head, neck and extremity symptoms (Meeker & Haldeman, 2002, p. 219). Also the article Chiropractic: A profession at the crossroads of mainstream and alternative medicine states that, “chiropractic was to be a revolutionary system of healing based on the premise that neurologic dysfunction caused by ‘impinged’ nerves at the spinal level was the cause of most dis-ease” (Meeker & Haldeman, 2002, p. 218). The mechanisms that are claimed to alter nervous system function and affect overall health are seen as speculative in nature, however, clinical trials have been conducted that include “placebo-controlled comparisons [and] comparisons with other treatments” (Meeker & Haldeman, 2002, p. 220). Out of 43 trials 30 preferred manipulation over the comparisons showing that the benefits of chiropractic can’t be seen as speculative in nature. There are many ways that a chiropractor can choose to help a person. Some of the techniques use adjustments in an effort to restore proper posture and curvatures, under the theory that “poor posture and physical injury, including birth trauma, may be common primary causes of illness in children and can have a direct and significant impact not only on spinal mechanics, but on other bodily functions”. Whether these effects are placebo related is speculative though. Regardless of the technique used, most emphasize the repetitive use of adjustments over time in an effort to retrain the body's nervous system.
The effects of spinal manipulation have been shown to include: temporary relief of musculoskeletal pain, increased range of joint motion, changes in facet joint kinematics, increased pain tolerance and increased muscle strength (Meeker & Haldeman, 2002, p. 222). Common side effects of spinal manipulative therapy (SMT) are characterized as mild to moderate and may include: local discomfort, headache, tiredness, or radiating discomfort (Meeker & Haldeman, 2002, p. 222).
The World Health Organization states that when "employed skillfully and appropriately, chiropractic care is safe and effective for the prevention and management of a number of health problems. As with all interventions, there are risks associated with spinal manipulative therapy (SMT). Common, but unserious side effects include: discomfort, headache, and fatigue which will go away after 24 to 48 hours. Infrequent, but potentially serious side effects include: strokes, spinal disc herniation, vertebral and rib fractures and cauda equina syndrome (Meeker & Haldeman, 2002, p. 222).