Difference between revisions of "Vertebral subluxation"

Latest revision as of 10:54, 23 April 2014

Overview

Subluxation or "joint dysfunction" is a term used by chiropractors to describe biomechanically restricted/fixated of the joints of the spine and extremities. It is this "manipulable lesion" that is the target of their main clinical intervention, spinal manipulation. Chiropractic medicine defines joint dysfunction/subluxation as a lesion or dysfunction in a joint or motion segment in which alignment, movement integrity and/or physiological function are altered, although contact between joint surfaces remains intact. It is essentially a functional entity, which may influence biomechanical and neural integrity.^[1] Cardinal biomechanical features of chiropractic joint dysfunction/subluxation is fixation/restriction and misalignment^[2] Chiropractic uniquely asserts that joint subluxation/dysfunction disrupts proper neurological function and that joint manipulation can restore proper biomechanical and neurological integrity^[3]

Chiropractic's theory subluxation/joint dysfunction and it's putative role in non-musculoskeletal disease has been a source of controversy since its inception in 1895 due its vitalistic and metaphysical origins which used vitalistic terminology that was not amenable to scientific investigation. Far reaching claims and lack of scientific evidence supporting spinal joint dysfunction as a cause of disease has led to a critical evaluation of a central tenet of chiropractic and the appropriateness of the profession's role in treating a broad spectrum disorders that are not related to the neuromusculoskeletal system.^[4] Although there is external and internal debate within the chiropractic profession regarding the clinical significance of joint dysfunction/subluxation^[5] the manipulable lesion remains inextricably linked to the profession as the rationale behind their approach to manual therapy and health care.

History/Present

The concept of a manipulable spinal lesion, the spinal joint subluxation/dysfunction, has been present since the the ancient Greeks. Hippocrates, known as the "Father of Medicine" (460-370 BC), dubbed these minor spinal displacements as "parathremata". He described manipulative procedures in his monumental work known as the "Corpus Hippocrateum". ^[6] D.D. Palmer (1845-1913) the "Father of Chiropractic" claimed that joint spinal dysfunction, the "vertebral subluxation" negatively affected the nervous system and could be corrected by spinal manipulation/adjustment. He postulated that specific spinal dysfunctions resulted in a lowered tissue resistance and potential disease in segmentally innervated tissues. He went so far as to suggest that the primary cause of all disease could be related to subluxations and interruption of normal "tone --nerves too tense or slack". B.J. Palmer (1882-1961) also promoted a monocausal concept of disease, a view that has been abandoned in profession today^[7] In May 2010 the General Chiropractic Council, the statutory regulatory body for chiropractors in the United Kingdom, issued a guidance note to chiropractors practicing "subluxation-based" chiropractic stating that the vertebral subluxation complex is a "historical concept but remains a theoretical model that is not supported by any clinical research evidence that would allow claims to be made that it is the cause of disease or health concerns."^[8] The monocausal concept runs contrary to much of the recent chiropractic literature and to the view of the "overwhelming majority" of practicing chiropractors. Although a small minority of chiropractors still promote Palmer's extreme view, both the profession's national associations in the United States and the international Council on Chiropractic Education have disavowed it^[9]

Components, Examination, Reimbusement

In the United States, Centers for Medicare and Medicaid Services (CMS), coverage of chiropractic services is specifically limited to manual manipulation of the spine to correct a subluxation. Utilization guidelines for chiropractic services require the following three components in order to establish medical necessity:

1. Presence of a subluxation that causes a significant neuromusculoskeletal condition.
2. Documentation of the Subluxation demonstrated by one of two methods: x-ray or physical examination. If documented by physical examination, the PART system (as described below) must be used.
3. Documentation of the Initial and Subsequent Visits

The PART system which is the physical examination of the joint dysfunction/subluxation includes the following components: Pain and tenderness, Asymmetry/misalignment, Range of motion abnormality and Tissue/tone changes. Two of the 4 components must be present for reimbursement under US Medicare.^[10] Chiropractors have traditionally described five components to the spinal joint dysfunction/subluxation. They include degenerative changes in neuromusculoskeletal system specifically:spinal kinesiopathology, neuropathophysiology/neuropathology, myopathology, histopathology. The fifth component, pathophysiology/pathology differentiates the theoretical construct of vertebral subluxation "complex" from joint dysfunction/subluxation. ^[11]

Basic Sciences

Spinal nerve roots
The formation of the spinal nerve from the dorsal and ventral roots
A spinal nerve with its anterior and posterior roots.
Latin	radix posterior
Gray's	subject #208 916
MeSH	Dorsal+Roots

V. Strang, D.C., describes several hypotheses on how a misaligned vertebra may cause interference to the nervous system in his book, Essential Principles of Chiropractic:^[12]

• Nerve compression hypothesis: suggests that when the vertebrae are out of alignment, the nerve roots and/or spinal cord can become pinched or irritated. While the most commonly referenced hypothesis, and easiest for a patient to understand, it may be the least likely to occur.
• Proprioceptive insult hypothesis: focuses on articular alterations causing hyperactivity of the sensory nerve fibers.
• Somatosympathetic reflex hypothesis: all the visceral organ functions can be reflexly affected by cutaneous or muscular stimulation.
• Somatosomatic reflex hypothesis: afferent impulses from one part of the body can result in reflex activity in other parts of the body.
• Viscerosomatic reflex hypothesis: visceral afferent fibers cause reflex somatic problems.
• Somatopsychic hypothesis: the effects of a subluxation on the ascending paths of the reticular activating system.
• Neurodystrophic hypothesis: focuses on lowered tissue resistance that results from abnormal innervation.
• Dentate ligament-cord distortion hypothesis: upper cervical misalignments can cause the dentate ligaments to put a stress on the spinal cord.
• Psychogenic hypothesis: emotions, such as stress, causing contraction in skeletal muscles.

The vertebral subluxation has been described as a syndrome with signs and symptoms which include: altered alignment; aberrant motion; palpable soft tissue changes; localized/referred pain; muscle contraction or imbalance; altered physiological function; reversible with adjustment/manipulation; focal tenderness.^[13]

Scientific investigation

Despite the chiropractic premise that joint dysfunction/subluxation resulted in deleterious biomechanical neurological changes to the locomotor system, it is only recently that serious scientific investigation has sought to understand the biological mechanisms resulting from joint dysfunction/subluxation. With the development of modern technology, research projects regarding joint immobilization/fixation has focused on animal models to study the effects of dysfunctional articulations. One theory espoused by the chiropractic profession was that abnormal joint mechanics resulted in a degenerative changes to the joint structure, including histological changes in the joints, corresponding soft tissues and neurological function. Preliminary investigation has yielded evidence that joint hypomobilty resulted in degenerative changes not seen in biomechanically normal joints..^[14]

Autonomic Nervous System
Blue = parasympathetic
Red = sympathetic

Chiropractic also asserts that spinal health and function are directly related to general health and well-being. Preliminary research concerning the intricate functioning of the nervous system suggests that this speculation may have some support. David Seaman, DC, MS reviewed the work of several researchers concerning autonomic nervous system relationship to the somatic tissues of the spine.^[15] He noted that Feinstein et al. were the first to clearly describe some symptoms associated with noxious irritation of spinal tissues. They injected hypertonic saline into interspinous tissues and paraspinal muscles of normal volunteers for the purpose of characterizing local and referred pain patterns that might develop. His observations included:

"The pain elicited from muscles was accompanied by a characteristic group of phenomena which indicated involvement of other than segmental somatic mechanisms. . . . The manifestations were pallor, sweating bradycardia, fall in blood pressure, subjective faintness, and nausea, but vomiting was not observed. Syncope occurred in two early procedures in the series of paravertebral injections and was subsequently avoided by quickly depressing the subject's head or by having him lie down at the first sign of faintness. These features were not proportional to the severity of or to the extent of radiation; on the contrary, they seemed to dominate the experience of subjects who complained of little pain, but who were overwhelmed by this distressing complex of symptoms."^[15]

Feinstein referred to these symptoms as autonomic concomitants. It is likely that these autonomic concomitants were caused by nociceptive stimulation of autonomic centers in the brainstem, particularly the medulla. Feinstein indicated that "this is an example of the ability of deep noxious stimulation to activate generalized autonomic responses independently of the relay of pain to conscious levels." In other words, pain may not be the symptomatic outcome of nociceptive stimulation of spinal structures. Such a conclusion has profound implications for the chiropractic profession. Clearly, patients do not need to be in pain to be candidates for spinal adjustments.^[15]

The efficacy and validity of spinal manipulation to address visceral disorders systems remains and is a source of controversy within the chiropractic and medical communities. Though research is ongoing on this topic, conclusions that support or refute the usefulness of spinal manipulation on organic disorders remains to be seen. Additionally, to complicate matters, chiropractic professors and researchers, Nansel and Szlazak, found that:

"the proper differential diagnosis of somatic (musculoskeletal) vs. visceral (organ) dysfunction represents a challenge for both the medical and chiropractic physician. The afferent convergence mechanisms, which can create signs and symptoms that are virtually indistinguishable with respect to their somatic vs. visceral etiologies, suggest it is not unreasonable that this somatic visceral-disease mimicry could very well account for the "cures" of presumed organ disease that have been observed over the years in response to various somatic therapies (e.g., spinal manipulation, acupuncture, Rolfing, Qi Gong, etc.) and may represent a common phenomenon that has led to "holistic" health care claims on the part of such clinical disciplines."^[16]

Considering this phenomenon, Seaman suggests that the chiropractic concept of joint complex (somatic) dysfunction should be incorporated into the differential diagnosis of pain and visceral symptoms because these dysfunctions often generate symptoms similar to those produced by true visceral disease and notes that this mimicry leads to unnecessary surgical procedures and medications.^[15]

Other chiropractic researchers have also questioned some of the claimed effects of vertebral subluxation:

"The literature supports the existence of somatovisceral and viscerosomatic reflexes, but there is little or no evidence to support the notion that the spinal derangements (often referred to as subluxations by chiropractors) can cause prolonged aberrant discharge of these reflexes. Equally unsupported in the literature is the notion that the prolonged activation of these reflexes will manifest into pathological state of tissues, and most relevantly, that the application of spinal manipulative therapy can alter the prolonged reflex discharge or be associated with a reversal of the pathological degeneration of the affected reflexes or tissues. The evidence that has been amassed is largely anecdotal or case report based and it has attracted much intra disciplinary debate because of its frequent association with certain approaches to management (largely described as being traditional or "philosophical" in nature)."^[17]

Still other chiropractic researchers state quite directly:

"... early chiropractic philosophy ... considered disease the result of spinal nerve dysfunction caused by misplaced (subluxated) vertebrae. Although rejected by medical science, this concept is still [2000] accepted by a minority of chiropractors."

"Indeed, many progressive chiropractors have rejected the historical concept of the chiropractic subluxation in favor of ones that more accurately describe the nature of the complex joint disfunctions they treat."^[18]

Researchers at the RMIT University-Japan, Tokyo studied reflex effects of vertebral subluxation with regards to the autonomic nervous system. They found that "recent neuroscience research supports a neurophysiologic rationale for the concept that aberrant stimulation of spinal or paraspinal structures may lead to segmentally organized reflex responses of the autonomic nervous system, which in turn may alter visceral function."^[19]

Professor Philip S. Bolton of the School of Biomedical Sciences at University of Newcastle, Australia writes in Journal of Manipulative and Physiological Therapeutics, "The traditional chiropractic vertebral subluxation hypothesis proposes that vertebral misalignment cause illness, disease, or both. This hypothesis remains controversial." His objective was, "To briefly review and update experimental evidence concerning reflex effects of vertebral subluxations, particularly concerning peripheral nervous system responses to vertebral subluxations. Data source: Information was obtained from chiropractic or, scientific peer-reviewed literature concerning human or animal studies of neural responses to vertebral subluxation, vertebral displacement or movement, or both." He concluded, "Animal models suggest that vertebral displacements and putative vertebral subluxations may modulate activity in group I to IV afferent nerves. However, it is not clear whether these afferent nerves are modulated during normal day-to-day activities of living and, if so, what segmental or whole-body reflex effects they may have."^[20]

Conclusions: Monitoring mixed-nerve root discharges in response to spinal manipulative thrusts in vivo in human subjects undergoing lumbar surgery is feasible. Neurophysiologic responses appeared sensitive to the contact point and applied force vector of the spinal manipulative thrust. Further study of the neurophysiologic mechanisms of spinal manipulation in humans and animals is needed to more precisely identify the mechanisms and neural pathways involved.^[21]

Researchers at the Department of Physiology, University College London studied the effects of compression upon conduction in myelinated axons. Using pneumatic pressure of varying degrees on the sciatic nerves of frog specimens, the study supported the idea of nerve conduction failure as a result of compression.^[22]

Criticism

An area of debate among chiropractors and other medical professions is the confusion surrounding the term subluxation as it has been defined both as a descriptor of physical findings (joint dysfunction) as well as vitalistic philosophical construct that is not amenable to scientific investigation. Joseph Keating (1950-2007) a chiropractic historian noted the subluxation syndrome was a legitimate, testable, theoretical construct that was amenable to scientific investigation. He espoused an evidence-based approach to studying the joint dysfunction/subluxation that specifically distinguished the biomechanical manipulable lesion from subluxation dogma which asserted specifically a spinal joint dysfunction/subluxation was a clinically significant entity which led to disease.^[23] In March of 2010, in response to criticisms by the public, by the General Council of Chiropractic in the UK which issued a guidance note to chiropractors practicing an exclusively subluxation-based approach stating that the vertebral subluxation complex is a "historical concept but remains a theoretical model that is not supported by any clinical research evidence that would allow claims to be made that it is the cause of disease or health concerns.

Additional criticism comes from the fact that a minority of subluxation-based chiropractors who adhere rigidly to B.J. Palmer's monocausal concept of vertebral subluxation as the cause of all disease. Although the profession today emphasizes the important relationship between health and the structure and function of the neuromusculoskeletal system, it does not promote a monocausal concept of subluxation induced disease” ^[24]. The chiropractor, as merely as subluxation corrector, is not consistent with current evidence-informed practice guidelines nor the revised Council on Chiropractic Education (CCE) standards.^[25]. In short, contemporary chiropractic practice has evolved from a unicausal, unimodal approach that requires a much more complete analysis of the neuromusculoskeletal system and psychosocial determinants of health which is consistent with evidence-informed practice which has become the gold standard of the health care system in the 21st century.

References

pl:Podwichnięcie