The basis for spinal manipulation: Chiropractic perspective of indications and theory

A modern way to teach and practice manual therapy

BACKGROUND

Musculoskeletal conditions are the leading contributor to global disability and health burden. Manual therapy (MT) interventions are commonly recommended in clinical guidelines and used in the management of musculoskeletal conditions. Traditional systems of manual therapy (TMT), including physiotherapy, osteopathy, chiropractic, and soft tissue therapy have been built on principles such as clinician-centred assessment, patho-anatomical reasoning, and technique specificity. These historical principles are not supported by current evidence. However, data from clinical trials support the clinical and cost effectiveness of manual therapy as an intervention for musculoskeletal conditions, when used as part of a package of care.

PURPOSE

The purpose of this paper is to propose a modern evidence-guided framework for the teaching and practice of MT which avoids reference to and reliance on the outdated principles of TMT. This framework is based on three fundamental humanistic dimensions common in all aspects of healthcare: safety, comfort, and efficiency. These practical elements are contextualised by positive communication, a collaborative context, and person-centred care. The framework facilitates best-practice, reasoning, and communication and is exemplified here with two case studies.

METHODS

A literature review stimulated by a new method of teaching manual therapy, reflecting contemporary evidence, being trialled at a United Kingdom education institute. A group of experienced, internationally-based academics, clinicians, and researchers from across the spectrum of manual therapy was convened. Perspectives were elicited through reviews of contemporary literature and discussions in an iterative process. Public presentations were made to multidisciplinary groups and feedback was incorporated. Consensus was achieved through repeated discussion of relevant elements.

CONCLUSIONS

Manual therapy interventions should include both passive and active, person-empowering interventions such as exercise, education, and lifestyle adaptations. These should be delivered in a contextualised healing environment with a well-developed person-practitioner therapeutic alliance. Teaching manual therapy should follow this model.

Development and validation of the Chiropractic Professional Identity Embodiment Scale (CPIES)

BACKGROUND AND PURPOSE

Chiropractic professional identity (CPI) encompasses diverse values, beliefs, experiences, and philosophies about one's work, specific to the chiropractic profession. Yet currently, there is no instrument available to measure CPI. This study aimed to develop and validate the Chiropractic Professional Identity Embodiment Scale (CPIES).

MATERIALS AND METHODS

A mixed-methods sequential exploratory design was employed where qualitative inquiry preceded quantitative analysis of survey items conducted in New Zealand in 2022. Expert key informants provided feedback on candidate items via one-to-one cognitive interviews. Candidate items were administered to Board-registered chiropractors or chiropractic students through an online survey. The suitability of candidate items was evaluated using a variety of psychometric analyses including conceptually guided exploratory factor analysis (EFA) and reliability testing.

RESULTS

Based on relevant professional identity literature and feedback from 15 expert key informants, a draft survey instrument with 92 candidate items (across six domains) was rated by 231 participants. Using EFA, the number of items was reduced to 15. The CPIES sum score exhibited significant correlations with individuals' philosophical self-categorisation and five of the six optional subscales.

CONCLUSION

The 15-item CPIES, either as a unidimensional score or with six separate subscale scores, has been demonstrated to provide valid and reliable measurement of CPI. Future research could utilise the CPIES to investigate how CPI influences clinical practice, patient outcomes, career satisfaction, and public perception of the chiropractic profession, further advancing professionalisation and recognition within healthcare.

Cervical Spine Vibration Modifies Oculomotor Function in Young Adults with Traumatic Brain Injury

OBJECTIVE

The purpose of this study was to investigate if vibrational interference of spinal proprioception affects oculomotor function, visual attention and processing, and selective attention in individuals with mild traumatic brain injury (mTBI) compared to healthy age-matched controls.

METHODS

This study was a parallel design, single-session intervention with 20 young adults with mTBI and 20 age-matched controls. Each completed a battery of computerized eye-tracking assessments (CEAs), including egocentric localization, fixational stability, smooth pursuit, saccades, Stroop, and the vestibulo-ocular reflex (VOR), and then had their cervical spine function (flexion-relaxation ratio) recorded at baseline. Spinal vibration (100 Hz) was applied to the cervical spine and the CEA battery was repeated. CEA outcomes were compared to baseline and between mTBI and control groups.

RESULTS

Following cervical vibration, significant pre to post-differences were seen in both the mTBI and control group for egocentric localization, fixation stability, pursuit, saccades, Stroop, and VOR. At baseline, there was a significant difference between the mTBI and control groups across many CEA measures, with the mTBI group performing more poorly in egocentric localization, pursuit, saccades, Stroop, and VOR. The mTBI group also had a poorer flexion-relaxation ratio than the control group.

CONCLUSION

Cervical spine vibration improved cognitive and oculomotor performance in the mTBI group for VOR, Stroop, and pursuit, but had mixed effects on the control group. These findings suggest that some optometric mTBI symptoms may result from spinal or proprioceptive dysfunction, as altering proprioceptive input appears to positively impact visual outcomes.

Effect of Chiropractic Intervention on Oculomotor and Attentional Visual Outcomes in Young Adults With Long-Term Mild Traumatic Brain Injury: A Randomized Controlled Trial

OBJECTIVE

This study aimed to establish if chiropractic care can improve oculomotor and cognitive symptoms in individuals with persistent postconcussion syndrome (PPCS).

METHODS

A single-blind, randomized controlled intervention study recorded baseline computerized eye-tracker assessment (CEA) outcomes in 40 young adults with PPCS following mild traumatic brain injury. Participants were randomly allocated to either a chiropractic or age-matched active control intervention, and the change in CEA outcomes following intervention was compared between the chiropractic and control groups. A battery of CEAs including egocentric localization, fixation stability, pursuit, saccades, Stroop, and the vestibulo-ocular reflex, were used to assess oculomotor function, visual attention/processing, and selective attention.

RESULTS

Relative to the control group, participants receiving the chiropractic intervention scored better in the Stroop test (P < .001), had improved gaze stability during both vestibulo-ocular reflex (P < .001) and fixation stability (P = .009), and a lower vertical error in egocentric localization (P < .001). However, performance was poorer in pursuits, where they had an increased tracking error (P < .001).

CONCLUSION

Chiropractic care in participants with PPCS significantly improved static and dynamic gaze stability, and performance in the Stroop test, compared with a control intervention. These results suggest that chiropractic care can offer a novel avenue for alleviating certain visual and cognitive symptoms in patients with PPCS. It also adds to the growing evidence that suggests that some longstanding PPCS visual symptoms may have a spinal or proprioceptive basis.

Veterinary Spinal Manipulative Therapy or Animal Chiropractic in Veterinary Rehabilitation

Veterinary rehabilitation is a multimodal diagnostic and treatment approach that is recommended and provided to patients daily. One therapeutic modality that may be beneficial (diagnostically and therapeutically) is veterinary spinal manipulative therapy or animal chiropractic (AC). AC is a receptor-based health-care modality being provided more frequently in veterinary practices. All clinicians should strive to understand the mode of action, indications, contraindications, how it affects the patient from the neuro-anatomical and biomechanical point of view, and most importantly, when not to provide the requested modality, as further diagnostics may be indicated.

The effect of lumbar spinal manipulation on biomechanical factors and perceived transient pain during prolonged sitting: a laboratory-controlled cross-sectional study

BACKGROUND

Spinal manipulation has been shown to affect muscle activity, posture, and pain. To date, no studies have examined the effect of manipulation on biomechanical factors during sitting. Therefore, the purpose of this study was to investigate the immediate effect of lumbar spinal manipulation on trunk muscle activation, spine posture and movements, and perceived ratings of transient pain in asymptomatic adults during prolonged office sitting.

METHODS

Twenty healthy adults were recruited for a single laboratory session that included a standardized office sitting/data entry protocol (120 min total, 3 blocks of 40 min). Data were collected between July and August 2012. The first block (baseline) was immediately followed by two experimental blocks. Prior to the start of each experimental block, participants were transferred to a therapy plinth and placed side lying (right side down), and a random presentation of either a control or high velocity low amplitude thrust directed at L4/L5 was delivered. Continuous measures of muscle activity, spine posture, and spine movements were recorded throughout the sitting trials. Perceived transient pain was measured by visual analogue scale at 10-min intervals (including immediately before and after the randomized maneuvers).

RESULTS

There were no significant differences in spine or pelvic posture or perceived back pain following either the manipulation or control maneuvers. Significantly reduced muscle activity and increased shifts of the lumbar spine angle were identified in the block following manipulation compared to both baseline and post control blocks.

CONCLUSIONS

Spinal manipulation does not appear to have an immediate impact on spine or pelvic posture in healthy adults but does appear to reduce muscle activity and increase spine movement during sitting. Future work should replicate this study with a larger population in a field setting. It may be worthwhile to explore the implication of reduced muscle activation and increased spine movements during prolonged sitting for office workers that receive manipulations or mobilizations during their workday.

Comparison of Concordance between Chuna Manual Therapy Diagnostic Methods (Palpation, X-ray, Artificial Intelligence Program) in Lumbar Spine: An Exploratory, Cross-Sectional Clinical Study

Before Chuna manual therapy (CMT), a manual therapy applied in Korean medicine, CMT spinal diagnosis using palpation or X-ray is performed. However, studies on the inter-rater concordance of CMT diagnostic methods, concordance among diagnostic methods, and standard CMT diagnostic methods are scarce. Moreover, no clinical studies have used artificial intelligence (AI) programs for X-ray image-based CMT diagnosis. Therefore, this study sought a feasible and standard CMT spinal diagnostic method and explored the clinical applicability of the CMT-AI program. One hundred participants were recruited, and the concordance within and among different diagnostic modalities was analyzed by dividing them into manual diagnosis (MD), X-ray image-based diagnosis (XRD) by experts and non-experts, and XRD using a CMT-AI program by non-experts. Regarding intra-group concordance, XRD by experts showed the highest concordance (used as a gold standard when comparing inter-group concordance), followed by XRD using the AI program, XRD by non-experts, and then MD. Comparing diagnostic results between the groups, concordance with the gold standard was the highest for XRD using the AI program, followed by XRD by non-experts, and MD. Therefore, XRD is a more reasonable CMT diagnostic method than MD. Furthermore, the clinical applicability of the CMT-AI program is high.

Evidence-Based Complementary and Alternative Orthopedic Veterinary Medicine

The use of complementary and alternative veterinary medicine (CAVM) continues to become more widespread, especially for the management of chronic pain conditions such as canine osteoarthritis. Many patients have comorbidities that preclude traditional medical options, have not adequately responded to conventional therapies, or have owners interested in pursuing a complementary approach. Evidence-based CAVM can serve as a safe and effective adjunct to manage chronic pain conditions. There is growing evidence in the veterinary literature for the use of acupuncture and some herbal supplements in the multimodal management of canine osteoarthritis. The majority of evidence supporting chiropractic is limited to equine and human literature.

Clinical Effectiveness and Efficacy of Chiropractic Spinal Manipulation for Spine Pain

Spine pain is a highly prevalent condition affecting over 11% of the world's population. It is the single leading cause of activity limitation and ranks fourth in years lost to disability globally, representing a significant personal, social, and economic burden. For the vast majority of patients with back and neck pain, a specific pathology cannot be identified as the cause for their pain, which is then labeled as non-specific. In a growing proportion of these cases, pain persists beyond 3 months and is referred to as chronic primary back or neck pain. To decrease the global burden of spine pain, current data suggest that a conservative approach may be preferable. One of the conservative management options available is spinal manipulative therapy (SMT), the main intervention used by chiropractors and other manual therapists. The aim of this narrative review is to highlight the most relevant and up-to-date evidence on the effectiveness (as it compares to other interventions in more pragmatic settings) and efficacy (as it compares to inactive controls under highly controlled conditions) of SMT for the management of neck pain and low back pain. Additionally, a perspective on the current recommendations on SMT for spine pain and the needs for future research will be provided. In summary, SMT may be as effective as other recommended therapies for the management of non-specific and chronic primary spine pain, including standard medical care or physical therapy. Currently, SMT is recommended in combination with exercise for neck pain as part of a multimodal approach. It may also be recommended as a frontline intervention for low back pain. Despite some remaining discrepancies, current clinical practice guidelines almost universally recommend the use of SMT for spine pain. Due to the low quality of evidence, the efficacy of SMT compared with a placebo or no treatment remains uncertain. Therefore, future research is needed to clarify the specific effects of SMT to further validate this intervention. In addition, factors that predict these effects remain to be determined to target patients who are more likely to obtain positive outcomes from SMT.

Radiography and Clinical Decision-Making in Chiropractic

The concern over x-ray exposure risks can overshadow the potential benefit of radiography, especially in cases where manual therapy is employed. Spinal malalignment cannot be accurately visualized without imaging. Manual therapy and the load tolerances of injured spinal tissues raise different criteria for the use of x-rays for spinal disorders than in medical practice. Current regulatory bodies rely on radiography risk assessments based on Linear-No-Threshold (LNT) risk models. There is a need to consider radiography guidelines for chiropractic which are different from those for medical practice. Radiography practice guidelines are summaries dominated by frequentist interpretations in the analysis of data from studies. In contrast, clinicians often employ a pseudo-Bayesian form of reasoning during the clinical decision-making process. The overrepresentation of frequentist perspectives in evidence-based practice guidelines alter decision-making away from practical assessment of a patient's needs, toward an overly cautious standard applied to patients without regard to their risk/benefit likelihoods relating to radiography. Guidelines for radiography in chiropractic to fully assess the condition of the spine and spinal alignment prior to manual therapy, especially with high velocity, low amplitude spinal manipulation (HVLA-SM), should necessarily differ from those used in medical practice.

The contemporary model of vertebral column joint dysfunction and impact of high-velocity, low-amplitude controlled vertebral thrusts on neuromuscular function

Purpose

There is growing evidence that vertebral column function and dysfunction play a vital role in neuromuscular control. This invited review summarises the evidence about how vertebral column dysfunction, known as a central segmental motor control (CSMC) problem, alters neuromuscular function and how spinal adjustments (high-velocity, low-amplitude or HVLA thrusts directed at a CSMC problem) and spinal manipulation (HVLA thrusts directed at segments of the vertebral column that may not have clinical indicators of a CSMC problem) alters neuromuscular function.

Methods

The current review elucidates the peripheral mechanisms by which CSMC problems, the spinal adjustment or spinal manipulation alter the afferent input from the paravertebral tissues. It summarises the contemporary model that provides a biologically plausible explanation for CSMC problems, the manipulable spinal lesion. This review also summarises the contemporary, biologically plausible understanding about how spinal adjustments enable more efficient production of muscular force. The evidence showing how spinal dysfunction, spinal manipulation and spinal adjustments alter central multimodal integration and motor control centres will be covered in a second invited review.

Results

Many studies have shown spinal adjustments increase voluntary force and prevent fatigue, which mainly occurs due to altered supraspinal excitability and multimodal integration. The literature suggests physical injury, pain, inflammation, and acute or chronic physiological or psychological stress can alter the vertebral column’s central neural motor control, leading to a CSMC problem. The many gaps in the literature have been identified, along with suggestions for future studies.

Conclusion

Spinal adjustments of CSMC problems impact motor control in a variety of ways. These include increasing muscle force and preventing fatigue. These changes in neuromuscular function most likely occur due to changes in supraspinal excitability. The current contemporary model of the CSMC problem, and our understanding of the mechanisms of spinal adjustments, provide a biologically plausible explanation for how the vertebral column’s central neural motor control can dysfunction, can lead to a self-perpetuating central segmental motor control problem, and how HVLA spinal adjustments can improve neuromuscular function.

The Potential Mechanisms of High-Velocity, Low-Amplitude, Controlled Vertebral Thrusts on Neuroimmune Function: A Narrative Review

The current COVID-19 pandemic has necessitated the need to find healthcare solutions that boost or support immunity. There is some evidence that high-velocity, low-amplitude (HVLA) controlled vertebral thrusts have the potential to modulate immune mediators. However, the mechanisms of the link between HVLA controlled vertebral thrusts and neuroimmune function and the associated potential clinical implications are less clear. This review aims to elucidate the underlying mechanisms that can explain the HVLA controlled vertebral thrust--neuroimmune link and discuss what this link implies for clinical practice and future research needs. A search for relevant articles published up until April 2021 was undertaken. Twenty-three published papers were found that explored the impact of HVLA controlled vertebral thrusts on neuroimmune markers, of which eighteen found a significant effect. These basic science studies show that HVLA controlled vertebral thrust influence the levels of immune mediators in the body, including neuropeptides, inflammatory markers, and endocrine markers. This narravtive review discusses the most likely mechanisms for how HVLA controlled vertebral thrusts could impact these immune markers. The mechanisms are most likely due to the known changes in proprioceptive processing that occur within the central nervous system (CNS), in particular within the prefrontal cortex, following HVLA spinal thrusts. The prefrontal cortex is involved in the regulation of the autonomic nervous system, the hypothalamic-pituitary-adrenal axis and the immune system. Bi-directional neuro-immune interactions are affected by emotional or pain-related stress. Stress-induced sympathetic nervous system activity also alters vertebral motor control. Therefore, there are biologically plausible direct and indirect mechanisms that link HVLA controlled vertebral thrusts to the immune system, suggesting HVLA controlled vertebral thrusts have the potential to modulate immune function. However, it is not yet known whether HVLA controlled vertebral thrusts have a clinically relevant impact on immunity. Further research is needed to explore the clinical impact of HVLA controlled vertebral thrusts on immune function.

Neurophysiological mechanisms of chiropractic spinal manipulation for spine pain

Together, neck pain and back pain are the first cause of disability worldwide, accounting for more than 10% of the total years lived with disability. In this context, chiropractic care provides a safe and effective option for the management of a large proportion of these patients. Chiropractic is a healthcare profession mainly focused on the spine and the treatment of spinal disorders, including spine pain. Basic studies have examined the influence of chiropractic spinal manipulation (SM) on a variety of peripheral, spinal and supraspinal mechanisms involved in spine pain. While spinal cord mechanisms of pain inhibition contribute at least partly to the pain-relieving effects of chiropractic treatments, the evidence is weaker regarding peripheral and supraspinal mechanisms, which are important components of acute and chronic pain. This narrative review highlights the most relevant mechanisms of pain relief by SM and provides a perspective for future research on SM and spine pain, including the validation of placebo interventions that control for placebo effects and other non-specific effects that may be induced by SM. SIGNIFICANCE: Spinal manipulation inhibits back and neck pain partly through spinal segmental mechanisms and potentially through peripheral mechanisms regulating inflammatory responses. Other mechanisms remain to be clarified. Controls and placebo interventions need to be improved in order to clarify the contribution of specific and non-specific effects to pain relief by spinal manipulative therapy.

Informed consent, duty of disclosure and chiropractic: where are we?

BACKGROUND

The COVID-19 pandemic has seen the emergence of unsubstantiated claims by vertebral subluxation-based chiropractors that spinal manipulative therapy has a role to play in prevention by enhancing the body's immune function. We contend that these claims are unprofessional and demonstrate a disturbing lack of insight into the doctrine of informed consent. As such it is timely to review how informed consent has evolved and continues to do so and also to discuss the attendant implications for contemporary health practitioner practice. We review the origins of informed consent and trace the duty of disclosure and materiality through landmark medical consent cases in four common law (case law) jurisdictions. The duty of disclosure has evolved from a patriarchal exercise to one in which patient autonomy in clinical decision making is paramount. Passing time has seen the duty of disclosure evolve to include non-medical aspects that may influence the delivery of care. We argue that a patient cannot provide valid informed consent for the removal of vertebral subluxation. Further, vertebral subluxation care cannot meet code of conduct standards because it lacks an evidence base and is practitioner-centered. The uptake of the expanded duty of disclosure has been slow and incomplete by practitioners and regulators. The expanded duty of disclosure has implications, both educative and punitive for regulators, chiropractic educators and professional associations. We discuss how practitioners and regulators can be informed by other sources such as consumer law. For regulators, reviewing and updating informed consent requirements is required. For practitioners it may necessitate disclosure of health status, conflict of interest when recommending "inhouse" products, recency of training after attending continuing professional development, practice patterns, personal interests and disciplinary findings.

CONCLUSION

Ultimately such matters are informed by the deliberations of the courts. It is our opinion that the duty of a mature profession to critically self-evaluate and respond in the best interests of the patient before these matters arrive in court.

The effect on clinical outcomes when targeting spinal manipulation at stiffness or pain sensitivity: a randomized trial

The mechanisms underlying pain relief following spinal manipulative therapy (SMT) are not understood fully although biomechanical and neurophysiological processes have been proposed. As such, we designed this randomized trial to elucidate the contributions of biomechanical and neurophysiological processes. A total of 132 participants with low back pain were randomly assigned to receive SMT at either the lumbar segment measured as the stiffest or the segment measured as having the lowest pain threshold. The primary outcome was patient reported low back pain intensity following treatment. Secondary outcomes were biomechanical stiffness and neurophysiological pressure pain threshold. All outcomes were measured at baseline, after the fourth and final session and at 2-weeks follow-up. Data were analyzed using linear mixed models, and demonstrated that the SMT application site did not influence patient reported low back pain intensity or stiffness. However, a large and significant difference in pressure pain threshold was observed between groups. This study provides support that SMT impacts neurophysiological parameters through a segment-dependent neurological reflex pathway, although this do not seem to be a proxy for improvement. This study was limited by the assumption that the applied treatment was sufficient to impact the primary outcome.

Moving towards a contemporary chiropractic professional identity

Since the inception of the chiropractic profession, debate has continued on differing practice objectives and philosophical approaches to patient care. While the political and academic leaders of the profession continue to dominate the discourse, little is known on the perspectives of the everyday practising chiropractor on their professional identity. In this paper, professional identity within the profession of chiropractic was evaluated using a systematised search strategy of the literature from the year 2000 through to May 2019. Initially 562 articles were sourced, of which 24 met the criteria for review. The review confirmed three previously stated professional identity subgroups; two polarised approaches and a centrist or mixed view. The musculoskeletal biomedical approach is in contrast to the vertebral subluxation vitalistic practice approach. Whilst these three main chiropractic identity subtypes exist, within the literature the terminology used to describe them differs. Research aimed at categorising the chiropractic profession identity into exclusive subtypes found that at least 20% of chiropractors have an exclusive vertebral subluxation focus. However, deeper exploration of the literature shows that vertebral subluxation is an important practice consideration for up to 70% of chiropractors. Patient care with a musculoskeletal spine focus is dominant in clinical practice. This review found that practising chiropractors consider themselves to be primary care or primary contact practitioners with a broad scope of practice across a number of patient groups not limited to musculoskeletal management. Across the research, there is a marked difference in the categories of practice objectives evaluated, and future research could examine the relatedness of these. Additionally, future research could explore the professional identity construct over time and within different practice contexts to help facilitate the progression of the profession.

Influence of body position and axial load on spinal stiffness in healthy young adults

PURPOSE

This study aimed at investigating the effects of different body positions and axial loads on spinal stiffness to better understand spinal stabilisation mechanisms.

METHODS

The posterior-to-anterior lumbar and thoracic spinal stiffness of 100 young healthy adults (mean age 23 years; 50 females) were measured in three test situations: prone, standing and standing while carrying a load equal to 50% of the subject's body weight. Each test situation comprised three trials.

RESULTS

Spinal stiffness in all test situations showed good reliability. Repeated measures analysis of covariance showed significantly higher spinal stiffness in standing than in the prone position [F(1/1694) = 433.630, p < 0.001]. However, spinal stiffness was significantly lower when standing while carrying a load of 50% of the body weight than when standing without additional load [F(1/1494) = 754.358, p < 0.001].

CONCLUSION

This study showed that spinal lumbar and thoracic stiffness increases when body position is changed from prone to standing. Additional axial load of 50% of the subject's body weight results in reduced spinal stiffness during standing. These slides can be retrieved under Electronic Supplementary Material.

Doing the Same Thing and Expecting a Different Outcome: It Is Time for a Questioning Philosophy and Theory-Driven Chiropractic Research

OBJECTIVE

The purpose of this commentary is to discuss the philosophical and hypothetical underpinnings of chiropractic and consider whether there is a need for chiropractic to have a questioning philosophy and theory-driven process to guide future scientific endeavors in the profession.

DISCUSSION

The earliest beliefs of the chiropractic founders centered on chiropractic vertebral subluxation but differed on whether this was a static, bone-out-of-place misalignment or a lesion whereby joints had lost their normal direction or range of motion. More recently, new hypotheses such as dyskinesia, inflammation, and neuroplasticity attempt to explain the purported clinical effects of chiropractic. Yet practitioners and students advocate for both traditional viewpoints that typically tout misalignment and embrace a science of chiropractic. I propose that chiropractors should not have to choose between philosophy and science. Instead, they should advocate for adoption of a modern questioning philosophy that not only informs their clinical questions and drives their theories, but also that is in turn influenced by outcomes from their research. Such a questioning philosophy is in stark contrast with the dogma that some have mislabeled as "philosophy" in the profession. I recommend that a review of chiropractic hypotheses and a theory-driven research process is needed to help guide the profession's research agenda given its wide range of clinical activities and limited resources. As the chiropractic profession increasingly embraces evidence-informed practice, enhanced integration within the wider health care community may then result in further gains in utilization.

CONCLUSION

Theory-driven research that results from and subsequently informs a questioning philosophy may expose truths related to practice behaviors, activities, and outcomes, and spur more complete integration of chiropractic within the wider health care community.

Remission of anosmia in a patient receiving chiropractic care: A case report

OBJECTIVE

To chronicle the remission of anosmia in a 79-year-old female receiving chiropractic care using the Activator Methods Chiropractic Technique (AMCT) protocol.

CLINICAL FEATURES

A 79-year-old white female with a 4-year history of medically diagnosed anosmia. Postural alterations, reduction in cervical ranges of motion (ROM), and absent cranial nerve I function were found in conjunction with vertebral subluxation throughout the spine and mild to severe degenerative changes throughout the spine present on radiographic studies.

INTERVENTION & OUTCOMES

Chiropractic care using AMCT was provided for the assessment and correction of vertebral subluxations. The patient reported subjective improvement in olfaction, physical functioning and life enjoyment, and demonstrated objective improvement in posture, cervical ROM, cranial nerve I function.

CONCLUSION

A course of chiropractic care, following the AMCT protocol, was associated with remission of anosmia.

Effects of spinal manipulative therapy biomechanical parameters on clinical and biomechanical outcomes of participants with chronic thoracic pain: a randomized controlled experimental trial

BACKGROUND

Spinal manipulative therapy (SMT) includes biomechanical parameters that vary between clinicians, but for which the influence on the therapy clinical effects is unknown. This parallel-randomized controlled trial aimed to investigate the effect of SMT biomechanical parameters on the outcomes of participants with chronic thoracic pain (CTP) following three treatment sessions (follow-up at one week).

METHODS

Adults reporting CTP (pain within the evaluated region [T6 to T8] for ≥3 months) were asked to participate in a four-session trial. At the first session, participants were randomly assigned to one of three experimental groups (different SMT doses) or the control group (no SMT). During the first three sessions, one SMT was executed at T7 for the experimental groups, while a 5-min rest was provided to the control group. SMT were delivered through an apparatus using a servo-controlled linear actuator motor and doses consisted of peak forces, impulse durations, and rates of force application set at 135 N, 125 ms and 920 N/s (group 1), at 250 N, 125 ms and 1840 N/s (group 2), and at 250 N, 250 ms, 920 N/s (group 3). Disability and pain intensity were evaluated at each session (primary outcomes). Spinal stiffness was assessed before-and-after each SMT/rest and at follow-up. Tenderness and muscle activity were evaluated during each spinal stiffness trial. Improvement was evaluated at follow-up. Differences in outcomes between groups and sessions were evaluated as well as factors associated with clinical improvement.

RESULTS

Eighty-one participants were recruited and 17, 20, 20 participants of the three experimental groups and 18 of the control group completed the protocol. In exception of higher pain intensity at baseline in the control group, no between-group differences were found for any of the outcomes. A decrease in pain intensity, disability, spinal stiffness, and tenderness during spinal stiffness were observed (p-values< 0.05). At follow-up, 24% of participants were classified as 'improved'. Predictors of improvement were a greater decrease in pain intensity and in tenderness (p-values< 0.05).

CONCLUSIONS

In an experimental setting, the delivery of a SMT does not lead to significantly different outcomes in participants with CTP than a control condition (spinal stiffness assessment). Studies are still required to explore the mechanisms underlying SMT effects.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03063177 , registered 24 February 2017).

Comparison of human lumbar disc pressure characteristics during simulated spinal manipulation vs. spinal mobilization

The present study aimed to investigate the differences in human lumbar intradiscal pressure (IDP) characteristics during simulated spinal manipulation and spinal mobilization. A total of 12 adult fresh lumbar spinal specimens (T12‑S2) were randomly divided into two groups. The parameters of simulated spinal mobilization were as follows: Preload angle, 15˚ (speed, 3˚/sec); maximum angle, 20˚ (speed, 1˚/sec); and 9 N horizontal force to the L5 spinous process. The parameters of simulated spinal manipulation were as follows: Preload angle, 15˚ (speed, 3˚/sec); impulse angle, 20˚ (impulse speed, 33˚/sec) and 22 N horizontal force to the L5 spinous process. The maximal IDP during both techniques was greater than the initial and end pressures (P<0.01). There was no difference between the initial and end IDP (P>0.05). The maximal IDP on the rotating side was greater than that on the contralateral side during the two techniques (P<0.05). There was no difference in both initial and end IDPs between the two sides (P>0.05). There was no difference in the maximal IDP between the two techniques (P>0.05). The ascending speed of IDP during manipulation was faster than during mobilization (P<0.01), while there was no difference in the descending speed between the two techniques (P>0.05). The maximal IDP on the rotating side was greater than the contralateral side during simulated spinal mobilization and manipulation (P<0.05). The ascending speed of IDP was faster during manipulation than mobilization (P<0.01). Therefore, thrust manipulation may have more instant impact to discs than mobilization.

Unraveling the Mechanisms of Manual Therapy: Modeling an Approach

Synopsis Manual therapy interventions are popular among individual health care providers and their patients; however, systematic reviews do not strongly support their effectiveness. Small treatment effect sizes of manual therapy interventions may result from a "one-size-fits-all" approach to treatment. Mechanistic-based treatment approaches to manual therapy offer an intriguing alternative for identifying patients likely to respond to manual therapy. However, the current lack of knowledge of the mechanisms through which manual therapy interventions inhibit pain limits such an approach. The nature of manual therapy interventions further confounds such an approach, as the related mechanisms are likely a complex interaction of factors related to the patient, the provider, and the environment in which the intervention occurs. Therefore, a model to guide both study design and the interpretation of findings is necessary. We have previously proposed a model suggesting that the mechanical force from a manual therapy intervention results in systemic neurophysiological responses leading to pain inhibition. In this clinical commentary, we provide a narrative appraisal of the model and recommendations to advance the study of manual therapy mechanisms. J Orthop Sports Phys Ther 2018;48(1):8-18. doi:10.2519/jospt.2018.7476.

The Physiological Role of Tumor Necrosis Factor in Human Immunity and Its Potential Implications in Spinal Manipulative Therapy: A Narrative Literature Review

OBJECTIVE

Although tumor necrosis factor (TNF) is a well-known inflammatory cytokine in the pathological development of various human diseases, its physiological roles are not widely understood nor appreciated. The molecular mechanisms underlying spinal manipulation therapy (SMT) remain elusive. The relationship between TNF and SMT is unclear. Thus, we performed this literature review to better understand TNF physiology and its potential relationship with SMT, and we propose a novel mechanism by which SMT may achieve clinical benefits by using certain beneficial features of TNF.

METHODS

We searched several databases for relevant articles published between 1975 and 2015 and then reexamined the studies from current immunophysiological perspectives.

RESULTS

The history and recent progresses in TNF physiology research were explored. Conflicting reports on the relationship between TNF and SMT were identified. Based on the newly discovered interaction between TNF and regulatory T cells, we proposed a putative biphasic TNF response to SMT, which may resolve the conflicts in the reported observations and interpretations.

CONCLUSION

The current literature about TNF informed our discussion of new physiological roles for TNF, which may help to better understand the physiological effects of SMT.

Changes in Quality of Life in 7 Older Adult Patients Receiving Activator Methods Chiropractic Technique

OBJECTIVE

The purpose of this case series is to report on symptomatic and quality of life (QoL) changes in 7 older adult chiropractic patients who were receiving care using Activator Methods Chiropractic Technique (AMCT).

CLINICAL FEATURES

Seven patients were selected from 2 chiropractic offices in Auckland, New Zealand. Patients were included if they were older adults receiving AMCT care and for whom at least 2 QoL assessments had been performed. The patients, aged 69-80 years, primarily received care for a variety of musculoskeletal complaints.

INTERVENTION AND OUTCOMES

The patients reported improvements in their presenting complaints as well as a number of nonmusculoskeletal symptoms. Each patient demonstrated clinical improvements in their RAND 36-Item Short Form Health Survey (SF-36) results. The average improvement in QoL measured using a SF-36 questionnaire was 8.0 points in the physical component and 4.1 points in the mental component. Four cases had a second progress evaluation using the SF-36 and showed an overall improvement of 5.2 in the physical and 9.8 in the mental components from baseline.

CONCLUSION

This case series describes an improvement in QoL, as measured by the SF-36 instrument, as well as subjectively reported improvements in both musculoskeletal and nonmusculoskeletal symptoms in 7 older adults receiving chiropractic care.

Antinociceptive Effects of Spinal Manipulative Therapy on Nociceptive Behavior of Adult Rats during the Formalin Test

Optimizing pain relief resulting from spinal manipulative therapies, including low velocity variable amplitude spinal manipulation (LVVA-SM), requires determining their mechanisms. Pain models that incorporate simulated spinal manipulative therapy treatments are needed for these studies. The antinociceptive effects of a single LVVA-SM treatment on rat nociceptive behavior during the commonly used formalin test were investigated. Dilute formalin was injected subcutaneously into a plantar hindpaw. Licking behavior was video-recorded for 5 minutes. Ten minutes of LVVA-SM at 20° flexion was administered with a custom-made device at the lumbar (L5) vertebra of isoflurane-anesthetized experimental rats (n = 12) beginning 10 minutes after formalin injection. Hindpaw licking was video-recorded for 60 minutes beginning 5 minutes after LVVA-SM. Control rats (n = 12) underwent the same methods except for LVVA-SM. The mean times spent licking the formalin-injected hindpaw of both groups 1–5 minutes after injection were not different. The mean licking time during the first 20 minutes post-LVVA-SM of experimental rats was significantly less than that of control rats (P < 0.001). The mean licking times of both groups during the second and third 20 minutes post-LVVA-SM were not different. Administration of LVVA-SM had a short-term, remote antinociceptive effect similar to clinical findings. Therefore, mechanistic investigations using this experimental approach are warranted.

What effect can manual therapy have on a patient's pain experience?

Manual therapy (MT) is a passive, skilled movement applied by clinicians that directly or indirectly targets a variety of anatomical structures or systems, which is utilized with the intent to create beneficial changes in some aspect of the patient pain experience. Collectively, the process of MT is grounded on clinical reasoning to enhance patient management for musculoskeletal pain by influencing factors from a multidimensional perspective that have potential to positively impact clinical outcomes. The influence of biomechanical, neurophysiological, psychological and nonspecific patient factors as treatment mediators and/or moderators provides additional information related to the process and potential mechanisms by which MT may be effective. As healthcare delivery advances toward personalized approaches there is a crucial need to advance our understanding of the underlying mechanisms associated with MT effectiveness.

Interrater Reliability of Motion Palpation in the Thoracic Spine

Introduction. Manual therapists commonly use assessments of intervertebral motion to determine the need for spinal manipulation, but the reliability of these procedures demonstrates conflicting results. The objectives of this study were to investigate the interrater reliability of thoracic spine motion palpation for perceived joint restriction and pain. Methods. Twenty-five participants between the ages of 18 and 70, with or without mid-back pain, were enrolled. Two raters motion palpated marked T5–T12 levels using two methods (standardised and pragmatic) and noted any restricted or painful segments. We calculated agreement between two raters by generating raw agreement percentages and Kappa coefficients with 95% confidence intervals. Results. There was poor to low level of agreement between the raters for both joint stiffness and pain localization using both pragmatic and standardized approaches. The results did not improve significantly when we conducted a post hoc analysis where three spinal levels were collapsed as one and right and left sides were also combined. Conclusions. The results for interrater reliability were poor for motion restriction and pain. These findings may have unfavourable implications for all manual therapists who use motion palpation to select patients appropriate for spinal manipulation.

Effect of spinal manipulation thrust duration on trunk mechanical activation thresholds of nociceptive-specific lateral thalamic neurons

OBJECTIVE

The objective of this preliminary study was to determine if high-velocity, low-amplitude spinal manipulation (HVLA-SM) thrust duration alters mechanical trunk activation thresholds of nociceptive-specific (NS) lateral thalamic neurons.

METHODS

Extracellular recordings were obtained from 18 NS neurons located in 2 lateral thalamic nuclei (ventrolateral [n = 12] and posterior [n = 6]) in normal anesthetized Wistar rats. Response thresholds to electronic von Frey anesthesiometer (rigid tip) mechanical trunk stimuli applied in 3 lumbar directions (dorsal-ventral, 45° caudal, and 45° cranial) were determined before and immediately after the delivery of 3 HVLA-SM thrust durations (time control 0, 100, and 400 milliseconds). Mean changes in mechanical trunk activation thresholds were compared using a mixed model analysis of variance.

RESULTS

High-velocity, low-amplitude spinal manipulation duration did not significantly alter NS lateral thalamic neurons' mechanical trunk responses to any of the 3 directions tested with the anesthesiometer.

CONCLUSIONS

This study is the first to examine the effect of HVLA-SM thrust duration on NS lateral thalamic mechanical response thresholds. High-velocity, low-amplitude spinal manipulation thrust duration did not affect mechanical trunk thresholds.

Criterion validity of manual assessment of spinal stiffness

Assessment of spinal stiffness is widely used by manual therapy practitioners as a part of clinical diagnosis and treatment selection. Although studies have commonly found poor reliability of such procedures, conflicting evidence suggests that assessment of spinal stiffness may help predict response to specific treatments. The current study evaluated the criterion validity of manual assessments of spinal stiffness by comparing them to indentation measurements in patients with low back pain (LBP). As part of a standard examination, an experienced clinician assessed passive accessory spinal stiffness of the L3 vertebrae using posterior to anterior (PA) force on the spinous process of L3 in 50 subjects (54% female, mean (SD) age = 33.0 (12.8) years, BMI = 27.0 (6.0) kg/m(2)) with LBP. A criterion measure of spinal stiffness was performed using mechanized indentation by a blinded second examiner. Results indicated that manual assessments were uncorrelated to criterion measures of stiffness (spearman rho = 0.06, p = 0.67). Similarly, sensitivity and specificity estimates of judgments of hypomobility were low (0.20-0.45) and likelihood ratios were generally not statistically significant. Sensitivity and specificity of judgments of hypermobility were not calculated due to limited prevalence. Additional analysis found that BMI explained 32% of the variance in the criterion measure of stiffness, yet failed to improve the relationship between assessments. Additional studies should investigate whether manual assessment of stiffness relates to other clinical and biomechanical constructs, such as symptom reproduction, angular rotation, quality of motion, or end feel.

Neural responses to the mechanical parameters of a high-velocity, low-amplitude spinal manipulation: effect of preload parameters

OBJECTIVE

The purpose of this study was to determine how the preload that precedes a high-velocity, low-amplitude spinal manipulation (HVLA-SM) affects muscle spindle input from lumbar paraspinal muscles both during and after the HVLA-SM.

METHODS

Primary afferent activity from muscle spindles in lumbar paraspinal muscles were recorded from the L6 dorsal root in anesthetized cats. High-velocity, low-amplitude spinal manipulation of the L6 vertebra was preceded either by no preload or systematic changes in the preload magnitude, duration, and the presence or absence of a downward incisural point. Immediate effects of preload on muscle spindle responses to the HVLA-SM were determined by comparing mean instantaneous discharge frequencies (MIF) during the HVLA-SM's thrust phase with baseline. Longer lasting effects of preload on spindle responses to the HVLA-SM were determined by comparing MIF during slow ramp and hold movement of the L6 vertebra before and after the HVLA-SM.

RESULTS

The smaller compared with the larger preload magnitude and the longer compared with the shorter preload duration significantly increased (P = .02 and P = .04, respectively) muscle spindle responses during the HVLA-SM thrust. The absence of preload had the greatest effect on the change in MIF. Interactions between preload magnitude, duration, and downward incisural point often produced statistically significant but arguably physiologically modest changes in the passive signaling properties of the muscle spindle after the manipulation.

CONCLUSION

Because preload parameters in this animal model were shown to affect neural responses to an HVLA-SM, preload characteristics should be taken into consideration when judging this intervention's therapeutic benefit in both clinical efficacy studies and in clinical practice.

Effects of unilateral facet fixation and facetectomy on muscle spindle responsiveness during simulated spinal manipulation in an animal model

OBJECTIVES

Manual therapy practitioners commonly assess lumbar intervertebral mobility before deciding treatment regimens. Changes in mechanoreceptor activity during the manipulative thrust are theorized to be an underlying mechanism of spinal manipulation (SM) efficacy. The objective of this study was to determine if facet fixation or facetectomy at a single lumbar level alters muscle spindle activity during 5 SM thrust durations in an animal model.

METHODS

Spinal stiffness was determined using the slope of a force-displacement curve. Changes in the mean instantaneous frequency of spindle discharge were measured during simulated SM of the L6 vertebra in the same 20 afferents for laminectomy-only and 19 laminectomy and facet screw conditions; only 5 also had data for the laminectomy and facetectomy condition. Neural responses were compared across conditions and 5 thrust durations (≤ 250 milliseconds) using linear-mixed models.

RESULTS

Significant decreases in afferent activity between the laminectomy-only and laminectomy and facet screw conditions were seen during 75-millisecond (P < .001), 100-millisecond (P = .04), and 150-millisecond (P = .02) SM thrust durations. Significant increases in spindle activity between the laminectomy-only and laminectomy and facetectomy conditions were seen during the 75-millisecond (P < .001) and 100-millisecond (P < .001) thrust durations.

CONCLUSION

Intervertebral mobility at a single segmental level alters paraspinal sensory response during clinically relevant high-velocity, low-amplitude SM thrust durations (≤ 150 milliseconds). The relationship between intervertebral joint mobility and alterations of primary afferent activity during and after various manual therapy interventions may be used to help to identify patient subpopulations who respond to different types of manual therapy and better inform practitioners (eg, chiropractic and osteopathic) delivering the therapeutic intervention.

Belief reinforcement: one reason why costs for low back pain have not decreased

Recent figures show that there has been no change in the upward trend of direct and indirect costs for the largely benign symptom of low back pain in Western societies. This is despite greater understanding and the recommendation of a much more conservative and independent approach to its management. Moreover, in recent years, several large-scale education programs that aim to bring knowledge of the public (including general practitioners) more in line with evidence-based best practice were carried out in different countries. The hope was that the information imparted would change beliefs, ie, dysfunctional patient behavior and biomedical practice on the part of clinicians. However, these programs had no influence on behavior or costs in three out of the four countries in which they were implemented. It is argued that one reason for the overall lack of success is that it is extremely difficult to alter the potentially disabling belief among the lay public that low back pain has a structural mechanical cause. An important reason for this is that this belief continues to be regularly reinforced by the conditions of care of a range of "hands-on" providers, for whom idiosyncratic variations of that view are fundamental to their professional existence.