About Chiropractic Adjusting
a.k.a.   Spinal Manipulation

This section was compiled by Frank M. Painter, D.C.
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The Chiropractic Technique Page
A Chiro.Org article collection

The Technique page contains articles about chiropractic techniques, as well as links to various named-technique websites.

Instrument Adjusting, a.k.a. Mechanically-assisted Adjustments
A Chiro.Org article collection

This page gathers articles discussing the use of mechanically-assisted instrument adjusting.

What is the Chiropractic Subluxation?
A Chiro.Org article collection

This extensive collection contains a wide variety of articles about the Subluxation Complex, and it's impact on the nervous system and health.

   2 Featured Articles   

  DC’s Perform Most Manipulations and Receive Most Eduaction
In their 1992 study, the RAND Corporation confirmed that chiropractors perform 94% of all spinal manipulation procedures in the U.S. with osteopaths delivering just 4% and general practitioners and orthopedic surgeons performing the remaining 2%. In light of the AHCPR's findings, we must be prepared for these figures to change as spinal manipulation becomes more accepted as a viable treatment of choice.

Adjusting the Pediatric Spine
Topics in Clinical Chiropractic 1997; 4 (4): 59–69 ~ FULL TEXT

The subject of chiropractic care of children must by necessity include a discussion of the various techniques chiropractors use to address a subluxation. [1, 2] The act of introducing a force into a spinal joint in an effort to restore mobility or alignment is termed an adjustment. This article discusses the technical aspects of adjusting the pediatric spine (ie, occiput to pelvis).

Spinal Manipulation Therapy: Is It All About the Brain?
A Current Review of the Neurophysiological
Effects of Manipulation

J Integrative Medicine 2019 (Sep); 17 (5): 328–337 ~ FULL TEXT

In this article, we reviewed the relevance of various neurophysiological theories with respect to the findings of mechanistic studies that demonstrated neural responses following spinal manipulation. This article also discussed whether these neural responses are associated with the possible neurophysiological mechanisms of spinal manipulation. The body of literature reviewed herein suggested some clear neurophysiological changes following spinal manipulation, which include neural plastic changes, alteration in motor neuron excitability, increase in cortical drive and many more. However, the clinical relevance of these changes in relation to the mechanisms that underlie the effectiveness of spinal manipulation is still unclear. In addition, there were some major methodological flaws in many of the reviewed studies. Future mechanistic studies should have an appropriate study design and methodology and should plan for a long-term follow-up in order to determine the clinical significance of the neural responses evoked following spinal manipulation.

Intervertebral Kinematics of the Cervical Spine
Before, During, and After High-velocity
Low-amplitude Manipulation

Spine J 2018 (Dec); 18 (12): 2333–2342

This study is the first to measure facet gapping during cervical manipulation on live humans. The results demonstrate that target and adjacent motion segments undergo facet joint gapping during manipulation and that intervertebral ROM is increased in all three planes of motion after manipulation. The results suggest that clinical and functional improvement after manipulation may occur as a result of small increases in intervertebral ROM across multiple motion segments. This study demonstrates the feasibility of characterizing in real time the manual inputs and biological responses that comprise cervical manipulation, including clinician-applied force, facet gapping, and increased intervertebral ROM. This provides a basis for future clinical trials to identify the mechanisms behind manipulation and to optimize the mechanical factors that reliably and sufficiently impact the key mechanisms behind manipulation.

A Replication of the Ernst Study
“Adverse Effects of Spinal Manipulation:
A Systematic Review”

Chiropractic & Manual Therapies 2012 (Sep 21) ~ FULL TEXT

The number of errors or omissions in the 2007 Ernest paper, reduce the validity of the study and the reported conclusions. The omissions of potential risk factors and the timeline between the adverse event and SMT could be significant confounding factors. Greater care is also needed to distinguish between chiropractors and other health practitioners when reviewing the application of SMT and related adverse effects.

The Biomechanics of Spinal Manipulation
J Bodyw Mov Ther. 2010 (Jul); 14 (3): 280–286 ~ FULL TEXT

Biomechanics is the science that deals with the external and internal forces acting on biological systems and the effects produced by these forces. Here, we describe the forces exerted by chiropractors on patients during high-speed, low-amplitude manipulations of the spine and the physiological responses produced by the treatments. The external forces were found to vary greatly among clinicians and locations of treatment on the spine. Spinal manipulative treatments produced reflex responses far from the treatment site, caused movements of vertebral bodies in the "para-physiological" zone, and were associated with cavitation of facet joints. Stresses and strains on the vertebral artery during chiropractic spinal manipulation of the neck were always much smaller than those produced during passive range of motion testing and diagnostic procedures.

Does Facet Joint Inflammation Induce Radiculopathy?
An Investigation Using a Rat Model of
Lumbar Facet Joint Inflammation

Spine 2007 (Feb 15); 32 (4): 406–412

The association between lumbar facet joint inflammation and radiculopathy was investigated using behavioral, histologic, and immunohistochemical testing in rats. Both mechanical and chemical factors have been identified as important for inducing radiculopathy. In lumbar spondylosis, facet joint osteophytes may contribute to nerve root compression, which may induce radiculopathy. Furthermore, inflammation may occur in the facet joint, as in other synovial joints. Inflamed synovium may thus release inflammatory cytokines and induce nerve root injury with subsequent radiculopathy. (In this study) when inflammation was induced in a facet joint, inflammatory reactions spread to nerve roots, and leg symptoms were induced by chemical factors. These results support the possibility that facet joint inflammation induces radiculopathy.
There are more articles like this at our Radiculopathy and Chiropractic Page.

A Hypothesis of Chronic Back Pain: Ligament Subfailure
Injuries Lead to Muscle Control Dysfunction

European Spine Journal 2006 (May); 15 (5): 668–676 ~ FULL TEXT

A new hypothesis of chronic back pain based upon muscle system dysfunction due to ligament injuries is described. Subfailure injuries of the ligaments and embedded mechanoreceptors generate corrupted mechanoreceptor signals. Consequently, the neuromuscular control unit produces corrupted muscle response pattern, resulting in excessive loading and, possibly, injuries of the spinal structures, including additional injuries of the mechanoreceptors. The hypothesis accounts for many of the common and important experimental observations and clinical findings seen in low back pain and whiplash patients. In the low back pain patients, it explains findings of delayed muscle response, poor balance, inefficient postural control, greater error in re-positioning the trunk, muscle spasm, and greater variability in the tasks performed. In the whiplash patients, both the decreased motion in active testing and increased motion in passive-relaxed testing are explained. The hypothesis proposes that the dysfunction of the muscle system over time may lead to chronic back pain via additional mechanoreceptor injury, and neural tissue inflammation.

Increased Multiaxial Lumbar Motion Responses During
Multiple-Impulse Mechanical Force Manually
Assisted Spinal Manipulation

Chiropractic & Osteopathy 2006 (Apr 6); 14 (1): 6 ~ FULL TEXT

Knowledge of the vertebral motion responses produced by impulse-type, instrument-based adjusting instruments provide biomechanical benchmarks that support the clinical rationale for patient treatment. Our results indicate that impulse-type adjusting instruments that deliver multiple impulse SMTs significantly increase multi-axial spinal motion.
There are more articles like this at our Instrument Adjusting Page.

A Revised Definition of Manipulation
J Manipulative Physiol Ther 2005 (Jan); 28 (1): ~ FULL TEXT

We write this commentary to address a problem that we feel exists in the description of chiropractic theory regarding the definition of spinal manipulation. We will first outline the background of the problem and then state the problem as it exists currently. We will then propose a revised definition to more accurately describe spinal manipulation.

Cavitation Emptor: Tracking the Holy Grail of Manipulation
Dynamic Chiropractic (September 13, 2004)

From Roston and Haynes' classic force-displacement curves of the third metacarpophalangeal joint in 1947, [1] through Sandoz' application of this phenomenon to manipulation, [2] through the criteria established by Mierau, Cassidy, et al., in 1988 to operationally differentiate manipulations from mobilizations, [3] chiropractors have held the audible release to be a virtual hallmark (if not a holy grail) of a successful manipulation. Indeed, an elegant model proposed by Raymond Brodeur, one of FCER's Peter Bommarito Residency Award-holders, has suggested [4] that the cavitation process provides a simple means for initiating reflex patterns associated with a manipulation. [5–7]

An Investigation into the Validity of Cervical Spine
Motion Palpation Using Subjects with Congenital
Block Vertebrae as a 'Gold Standard'

BMC Musculoskelet Disord 2004 (Jun 15); 5 (1): 19 ~ FULL TEXT

This study indicates that relatively inexperienced examiners are capable of correctly identifying inter-segmental fixations (CBV) in the cervical spine using 2 commonly employed motion palpation tests. The use of a 'gold standard' (CBV) in this study and the substantial agreement achieved lends support to the validity of motion palpation in detecting major spinal fixations in the cervical spine.
There are more articles like this at our Spinal Palpation Page.

Degenerative Changes Following Spinal Fixation in a
Small Animal Model

J Manipulative Physiol Ther 2004 (Mar); 27 (3): 141–154 ~ FULL TEXT

Fixed segments had more degenerative changes than nonfixed segments for all Z joint parameters (ANOVA, P <.0001). Osteophyte formation and ASD were directly dependent on duration of fixation. These findings indicate that fixation (hypomobility) results in time-dependent degenerative changes of the zygapophysial joints.
  You may also enjoy reviewing the FCER–funded research project that led to the publication of this article.

Neuromechanical Characterization of in vivo
Lumbar Spinal Manipulation.
Part I. Vertebral Motion

J Manipulative Physiol Ther. 2003 (Nov); 26 (9): 567–578 ~ FULL TEXT

In vivo kinematic measurements of the lumbar spine during the application of SMTs over the FJs and SPs corroborate previous spinous process measurements in human subjects. Our findings demonstrate that PA, ML, and AX spinal motions are coupled and dependent on applied force and contact point.

The Minimum Energy Hypothesis:
A Unified Model of Fixation Resolution

J Manipulative Physiol Ther 2002 (Feb); 25 (2): 105–110 ~ FULL TEXT

A unified theory of manipulative effectiveness is proposed that integrates the fixation and sensory tonus models of manipulation. The theory is based on the fact that the spine will assume a position of minimum internal energy when mechanical equilibrium is achieved. By using a simple mathematical model, it is shown that the fixation model and the sensory tonus models are 2 different aspects of the same theoretical construct. The Minimum Energy Hypothesis predicts that the spine will seek an optimal minimum energy configuration if the constraints preventing it from doing so are removed. Constraints are hypothesized to be joint fixations caused by inflammation in and about the spine and its sequella, muscle spasm, fibroadipose and scar tissue, and ultimately, degeneration. It is further hypothesized that the use of a computerized mechanical manipulative device may resolve such fixations, an example of which is radiographically demonstrable cervical hypolordosis.

The Effects of Mild Compression on Spinal Nerve Roots
with Implications for Models of Vertebral Subluxation
and the Clinical Effects of Chiropractic Adjustment

J Vertebral Subluxation Research 2001 (May); 4 (2): 1–13

There is evidence of nerve compression at the level of the intervertebral foramen (IVF) occurring anywhere from 15.4% to 78% of levels inspected. Most of the spines inspected were already prescreened to eliminate those that were definitely known to have nerve compression problems. Pressures as little as 10 mm Hg can alter the nerve root and dorsal root ganglion’s abilities to function normally. The concept that a vertebral subluxation can induce pressure increases at the level of the IVF is supported by the literature. This increase, though seemingly mild, is enough to alter nerve function. The garden hose theory or hard bone - soft nerve explanation of vertebral subluxation is considered by some to be archaic but appears to be a valid entity at least in the lower cervical spine. More research is needed to decipher the susceptibility to mild pressure increases throughout the spine.
There are more articles like this at our What is the Chiropractic Subluxation Page.

Biomechanics of Spinal Manipulative Therapy
Spine J. 2001 (Mar); 1 (2): 121–130 ~ FULL TEXT

There currently are a number of named systems of manual procedures. No current triage system is available that predicts which patient has the greater likelihood of benefiting from manual treatment or the procedure type. The biomechanical parameters of SMT form a systematic characterization of manual procedures. Such a system may be used in future studies to test hypotheses of treatment effect from quantitatively defined procedures.

Manual Healing Diversity and Other Challenges
to Chiropractic Integration

J Manipulative Physiol Ther 2000 (Mar); 23 (3): 202–207 ~ FULL TEXT

Chiropractic has made significant strides in establishing itself as a leading contender for integration in the emerging health care system.  However, recent articles in prominent medical journals illustrate key issues that must be resolved for chiropractic to fully establish itself within the new health care model.  Manual therapy diversity and the corollary question of whether chiropractic care should be defined solely in terms of the high velocity-low amplitude (HVLA) adjustment, are issues in need of urgent attention and analysis. Other problematic areas affecting chiropractic's integration into the health care mainstream include research methodology issues, treatment of visceral disorders, and professional relationships.

Neurologic Effects of the Adjustment
J Manipulative Physiol Ther. 2000 (Feb); 23 (2): 112–114 ~ FULL TEXT

This paper discusses the several theories pertaining to the chiropractic adjustment, including the nerve compression theory, reflex theories, and pain relief theories. There is now sufficient scientific research to consider these theories reasonable working models to explain the effects of the adjustment but insufficient to consider them valid.

Reflex Effects of Subluxation:
The Autonomic Nervous System

J Manipulative Physiol Ther 2000 (Feb); 23 (2): 104–106 ~ FULL TEXT

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.

Spinal Pain Syndromes:
Nociceptive, Neuropathic, and Psychologic Mechanisms

J Manipulative Physiol Ther 1999 (Sep); 22 (7): 458–472 ~ FULL TEXT

Although the treatment of neuropathic pain is difficult, sufficient evidence in the literature demonstrates that the treatment of nociceptive pain should be multimodal and involve spinal manipulation, muscle lengthening/stretching, trigger point therapy, rehabilitation exercises, electrical modalities, a variety of nutritional factors, and mental/emotional support.

Dysafferentation: A Novel Term to Describe the Neuropathophysiological
Effects of Joint Complex Dysfunction. A Look at Likely
Mechanisms of Symptom Generation

J Manipulative Physiol Ther 1998 (May); 21 (4): 267–280 ~ FULL TEXT

Joint complex dysfunction should be included in the differential diagnosis of pain and visceral symptoms because joint complex dysfunction can often generate symptoms which are similar to those produced by true visceral disease.
You may also enjoy this response from another chiropractic researcher.

Somatic Dysfunction and the Phenomenon of Visceral
Disease Simulation: A Probable Explanation for the
Apparent Effectiveness of Somatic Therapy in
Patients Presumed to be Suffering from
True Visceral Disease

J Manipulative Physiol Ther 1995 (Jul); 18 (6): 379–397 ~ FULL TEXT

The proper differential diagnosis of somatic vs. visceral 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, need to be appreciated by all portal-of-entry health care providers, to insure timely referral of patients to the health specialist appropriate to their condition. Furthermore, 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.

Biological Rationale for Possible Benefits of Spinal Manipulation
Chapter X; AHCPR Publication No. 98–N002: (December 1997) ~ FULL TEXT

Manipulation is a form of treatment that dates to antiquity and has been practiced in some form in most cultures since that time (Lomax, 1997; Anderson, 1992). One of the first theories related to manipulation might be the statement attributed to Hippocrates: "Look to the spine as the cause of disease." The theories of the early pioneers of chiropractic were firmly grounded in notions that had been widely held in the 1800s, particularly the idea of "spinal irritability" and its correlation with disease (Lomax, 1997; Terrett, 1987). Theories on the nature of the primary spinal disorder amenable to manipulation and on the mechanisms of action of spinal manipulation abound within chiropractic, osteopathy, physiotherapy, and manual medicine. The original chiropractic theory suggested that misaligned spinal vertebrae interfered with nerve function, ultimately resulting in altered physiology that could contribute to pain and disease. In recent decades, chiropractic theories about how mechanical spinal joint dysfunction might influence neurophysiology have undergone significant modification and reflect more contemporary views of physiology (Gatterman, 1995).



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