Using functional magnetic resonance imaging to determine if cerebral hemodynamic responses to pain change following thoracic spine thrust manipulation in healthy individuals

The Effect of Audible Joint Manipulation Sounds in the Upper Cervical Spine on Brain Wave and Autonomic Nervous System Activity

BACKGROUND

High-velocity, low-amplitude (HVLA) manipulation is a common manual therapy technique used for treating pain and musculoskeletal dysfunction. An audible manipulation sound is commonly experienced by patients who undergo HVLA manipulation; however, there is little known about the effects and clinical relevance of the audible manipulation sound on cortical output and the autonomic nervous system. This study aimed to identify the immediate impact of the audible manipulation sound on brainwave activity and pupil diameter in asymptomatic subjects following an HVLA cervical manipulation.

METHODS

40 subjects completed this quasi-experimental repeated measure study design. Subjects were connected to electroencephalography and pupillometry simultaneously, and an HVLA cervical distraction manipulation was performed. The testing environment was controlled to optimize brainwave and pupillometry data acquisition. Pre-manipulation, immediately after manipulation, and post-manipulation data were collected. The presence of an audible manipulation sound was noted.

RESULTS

Twenty subjects experienced an audible manipulation sound. Brainwave activity changes were significant (p < 0.05) in both the audible manipulation sound and non-manipulation sound groups. Pupil diameter changes (p < 0.05) occurred in both eyes of the non-manipulation sound group and in the left eye of the audible-manipulation sound group. Brainwave activity patterns were similar in both groups.

CONCLUSIONS

The presence of an audible manipulation sound is not required to produce central nervous system changes following an HVLA cervical manipulation; however, the audible manipulation sound does prolong the effects of brainwave activity, indicating a prolonged relaxation effect.

Effects of Sacroiliac Joint Manipulation on Autonomic Nervous System and Lower Abdominal Pain in Women with Primary Dysmenorrhoea: A Randomized Controlled Trial

Background and Objectives: Autonomic nervous system (ANS) disorders are responsible for primary dysmenorrhea and are closely linked to the spine. This study aims to evaluate the effects of sacroiliac joint manipulation on the ANS and lower abdominal pain in women with primary dysmenorrhea and proposes an alternative treatment method. Materials and Methods: A total of 40 participants were randomly assigned; however, 35 participants remained in the final analysis after 5 dropped out; they were assigned to either the sacroiliac joint manipulation group (n = 18) or the superficial heat therapy group (n = 17). Assessments included heart rate variability (HRV), visual analogue scale (VAS) scores for lower abdominal pain, the pressure pain threshold (PPT) of the sacroiliac joint, and the Moos Menstrual Distress Questionnaire (MMDQ) at baseline and after 4 weeks. Only the VAS and MMDQ scores were reassessed after 8 weeks to evaluate the sustained effects of the treatment. Results: Changes in HRV showed improvements in ANS balance only in the sacroiliac joint manipulation group (p < 0.05). It was found to be more effective than superficial heat therapy (p < 0.05). A significant decrease in lower abdominal pain following the intervention was observed in both groups (p < 0.05), along with the sustained effects of the treatment (p < 0.05). The MMDQ scores decreased after sacroiliac joint manipulation (p < 0.05), with greater improvements compared to the superficial heat therapy (p < 0.05). Conclusions: Sacroiliac joint manipulation positively affects ANS balance and is effective in alleviating lower abdominal pain and menstruation-related symptoms, with sustained effects observed over time. Therefore, sacroiliac joint manipulation can be an effective alternative treatment for women with primary dysmenorrhea.

Mulligan manual therapy added to exercise improves headache frequency, intensity and disability more than exercise alone in people with cervicogenic headache: a randomised trial

QUESTION

What is the effect of a 4-week regimen of Mulligan manual therapy (MMT) plus exercise compared with exercise alone for managing cervicogenic headache? Is MMT plus exercise more effective than sham MMT plus exercise? Are any benefits maintained at 26 weeks of follow-up?

DESIGN

A three-armed, parallel-group, randomised clinical trial with concealed allocation, blinded assessment of some outcomes and intention-to-treat analysis.

PARTICIPANTS

Ninety-nine people with cervicogenic headache as per International Classification of Headache Disorders (ICHD-3).

INTERVENTIONS

Participants were randomly allocated to 4 weeks of: MMT with exercise, sham MMT with exercise or exercise alone.

OUTCOME MEASURES

The primary outcome was headache frequency. Secondary outcomes were headache intensity, headache duration, medication intake, headache-related disability, upper cervical rotation range of motion, pressure pain thresholds and patient satisfaction. Outcome measures were collected at baseline and at 4, 13 and 26 weeks.

RESULTS

MMT plus exercise reduced headache frequency more than exercise alone immediately after the intervention (MD between groups in change from baseline: 2 days/month, 95% CI 2 to 3) and this effect was still evident at 26 weeks (MD 4 days, 95% CI 3 to 4). There were also benefits across all time points in several secondary outcomes: headache intensity, headache duration, headache-related disability, upper cervical rotation and patient satisfaction. Pressure pain thresholds showed benefits at all time points at the zygapophyseal joint and suboccipital areas but not at the upper trapezius. The outcomes in the sham MMT with exercise group were very similar to those of the exercise alone group.

CONCLUSIONS

In people with cervicogenic headache, adding MMT to exercise improved: headache frequency, intensity and duration; headache-related disability; upper cervical rotation; and patient satisfaction. These benefits were not due to placebo effects.

TRIAL REGISTRATION

CTRI/2019/06/019506.

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.

Association between myofascial trigger point therapy and conditioned pain modulation

INTRODUCTION

Myofascial trigger point therapy (MTrP) is a widely used therapeutic approach, although the underlying mechanisms remain unclear. Mechanisms discussed include peripheral involvement of muscles as well as central pain modulating processes such as the conditioned pain modulation (CPM). The aim of this study was to investigate whether the analgesic response of MTrP and the analgesic response of CPM correlate in asymptomatic participants in order to identify shared underlying mechanisms of MTrP and CPM.

METHOD

Both, CPM and MTrP protocols consisted of heat-based test stimuli (heat pain thresholds before and after the intervention) and pressure-based (conditioning) stimuli. Asymptomatic participants (n = 94) were randomly assigned to receive either mild, intense or no pressure stimuli (between-group design) to both the fingernail and the MTrP of the infraspinatus muscle (within-group design). Pressure stimuli at both locations (fingernail, MTrP) were applied with a pressure algometer for 120 s and continuously adjusted to maintain a constant pain intensity of mild or intense pain. All thermal stimuli were applied on the lower leg with a thermal stimulator.

RESULTS

A significant correlation was shown between the analgesic effect of CPM and MTrP therapy for mild (r = 0.53, p = 0.002) and intensive stimuli (r = 0.73, p < 0.001). 17.3% of the variance of the MTrP effect were explained by CPM after mild stimulation, and 47.1% after intense stimulation. Pain-related characteristics did not explain the variance within the analgesic response using a regression analysis.

CONCLUSIONS

Between the analgesic responses following MTrP and CPM paradigms, a moderate to strong correlation was observed, suggesting shared underlying mechanisms.

The combined effects of manual therapy and exercise on pain and related disability for individuals with nonspecific neck pain: A systematic review with meta-analysis

BACKGROUND

Neck pain is among the most prevalent and costly musculoskeletal disorders. Manual therapy and exercise are two standard treatment approaches to manage neck pain. In addition, clinical practice guidelines recommend a multi-modal approach, including both manual therapy and exercise for the treatment of neck pain; however, the specific effects of these combined interventions have not recently been reported in the literature.

OBJECTIVE

To perform a systematic review and meta-analysis to determine the effect of manual therapy combined with exercise on pain, disability, and quality of life in individuals with nonspecific neck pain.

DESIGN

Systematic Review and Meta-Analysis.

METHODS

Electronic database searches were completed in PubMed, CINAHL, Cochrane, EMBASE, Ovid, and SportDiscus, with publication dates of January 2000 to December 2022. The risk of bias in the included articles was completed using the Revised Cochrane Risk of Bias Tool (RoB 2). Raw data were pooled using standardized mean differences and mean differences for pain, disability, and quality of life outcomes, and forest plots were computed in the meta-analysis.

RESULTS

Twenty-two studies were included in the final review. With moderate certainty of evidence, three studies demonstrated no significant difference between manual therapy plus exercise and manual therapy alone in pain (SMD of -0.25 (95% CI: -0.52, 0.02)) or disability (-0.37 (95% CI: -0.92, 0.18)). With a low certainty of evidence, 16 studies demonstrated that manual therapy plus exercise is significantly better than exercise alone for reducing pain (-0.95 (95%CI: -1.38, -0.51)). Similarly, with low certainty of evidence, 13 studies demonstrated that manual therapy plus exercise is significantly better than exercise alone for reducing disability (-0.59 (95% CI: -0.90, -0.28)). Four studies demonstrated that manual therapy plus exercise is significantly better than a control intervention for reducing pain (moderate certainty) (-2.15 (95%CI: -3.58, -0.73)) and disability (low certainty) (-2.39 (95% CI: -3.80, -0.98)). With a high certainty of evidence, four studies demonstrated no significant difference between manual therapy plus exercise and exercise alone in quality of life (SMD of -0.02 (95% CI: -0.21, 0.18)).

CONCLUSION

Based on this systematic review and meta-analysis, a multi-modal treatment approach including exercise and manual therapy appears to provide similar effects as manual therapy alone, but is more effective than exercise alone or other interventions (control, placebo, 'conventional physical therapy', etc.) for the treatment of nonspecific neck pain and related disability. Some caution needs to be taken when interpreting these results given the general low to moderate certainty of the quality of the evidence.

Spinal Manipulative Therapy for Nonspecific Low Back Pain: Does Targeting a Specific Vertebral Level Make a Difference?: A Systematic Review With Meta-analysis

OBJECTIVE: We aimed to examine whether targeting spinal manipulative therapy (SMT), by applying the intervention to a specific vertebral level, produces superior clinical outcomes than a nontargeted approach in patients with nonspecific low back pain. DESIGN: Systematic review with meta-analysis. LITERATURE SEARCH: MEDLINE, Embase, CENTRAL, CINAHL, Scopus, PEDro, and Index to Chiropractic Literature were searched up to May 31, 2023. STUDY SELECTION CRITERIA: Randomized controlled trials comparing targeted SMT (mobilization or manipulation) to a nontargeted approach in patients with nonspecific low back pain, and measuring the effects on pain intensity and patient-reported disability. DATA SYNTHESIS: Data extraction, risk of bias, and evaluation of the overall certainty of evidence using the GRADE approach were performed by 2 authors independently. Meta-analyses were performed using the restricted maximum likelihood method. RESULTS: Ten randomized controlled trials (n = 931 patients) were included. There was moderate-certainty evidence of no difference between targeted SMT and a nontargeted approach for pain intensity at postintervention (weighted mean difference = -0.20 [95% CI: -0.51, 0.10]) and at follow-up (weighted mean difference = 0.05 [95% CI: -0.26, 0.36]). For patient-reported disability, there was moderate-certainty evidence of no difference at postintervention (standardized mean difference = -0.04 [95% CI: -0.36, 0.29]) and at follow-up (standardized mean difference = -0.05 [95% CI: -0.24, 0.13]). Adverse events were reported in 4 trials, and were minor and evenly distributed between groups. CONCLUSION: Targeting a specific vertebral level when administering SMT for patients with nonspecific low back pain did not result in improved outcomes on pain intensity and patient-reported disability compared to a nontargeted approach. J Orthop Sports Phys Ther 2023;53(9):1-11. Epub: 28 July 2023. doi:10.2519/jospt.2023.11962.

Knowledge, beliefs, and attitudes of spinal manipulation: a cross-sectional survey of Italian physiotherapists

BACKGROUND AND OBJECTIVE

High-velocity low-amplitude thrust spinal manipulation (SM) is a recommended and commonly used manual therapy intervention in physiotherapy. Beliefs surrounding the safety and effectiveness of SM have challenged its use, and even advocated for its abandonment. Our study aimed to investigate the knowledge and beliefs surrounding SM by Italian physiotherapists compared with similar practitioners in other countries.

METHODS

An online survey with 41 questions was adapted from previous surveys and was distributed via a mailing list of the Italian Physiotherapists Association (March 22-26, 2020). The questionnaire was divided into 4 sections to capture information on participant demographics, utilization, potential barriers, and knowledge about SM. Questions were differentiated between spinal regions. Attitudes towards different spinal regions, attributes associated with beliefs, and the influence of previous educational background were each evaluated.

RESULTS

Of the 7398 registered physiotherapists, 575 (7.8%) completed the survey and were included for analysis. The majority of respondents perceived SM as safe and effective when applied to the thoracic (74.1%) and lumbar (72.2%) spines; whereas, a smaller proportion viewed SM to the upper cervical spine (56.8%) as safe and effective. Respondents reported they were less likely to provide and feel comfortable with upper cervical SM (respectively, 27.5% and 48.5%) compared to the thoracic (respectively, 52.2% and 74.8%) and lumbar spines (respectively, 46.3% and 74.3%). Most physiotherapists (70.4%) agreed they would perform additional screening prior to upper cervical SM compared to other spinal regions. Respondents who were aware of clinical prediction rules were more likely to report being comfortable with SM (OR 2.38-3.69) and to perceive it as safe (OR 1.75-3.12). Finally, physiotherapists without musculoskeletal specialization, especially those with a traditional manual therapy background, were more likely to perform additional screening prior to SM, use SM less frequently, report being less comfortable performing SM, and report upper cervical SM as less safe (p < 0.001).

DISCUSSION

The beliefs and attitudes of physiotherapists surrounding the use of SM are significantly different when comparing the upper cervical spine to other spinal regions. An educational background in traditional manual therapy significantly influences beliefs and attitudes. We propose an updated framework on evidence-based SM.

The Changes of Brain Function After Spinal Manipulation Therapy in Patients with Chronic Low Back Pain: A Rest BOLD fMRI Study

OBJECTIVE

To investigate the changes of regional homogeneity (Reho) values before and after spinal manipulative therapy (SMT) in patients with chronic low back pain (CLBP) through rest blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD fMRI).

METHODS

Patients with CLBP (Group 1, n = 20) and healthy control subjects (Group 2, n = 20) were recruited. The fMRI was performed three times in Group 1 before SMT (time point 1, TP1), after the first SMT (time point 2, TP2), after the sixth SMT (time point 3, TP3), and for one time in Group 2, which received no intervention. The clinical scales were finished in Group 1 every time before fMRI was performed. The Reho values were compared among Group 1 at different time points, and between Group 1 and Group 2. The correlation between Reho values with the statistical differences and the clinical scale scores were calculated.

RESULTS

The bilateral precuneus and right mid-frontal gyrus in Group 1 had different Reho values compared with Group 2 at TP1. The Reho values were increased in the left precuneus and decreased in the left superior frontal gyrus in Group 1 at TP2 compared with TP1. The Reho values were increased in the left postcentral gyrus and decreased in the left posterior cingulate cortex and the superior frontal gyrus in Group 1 at TP3 compared with TP1. The ReHo values of the left precuneus in Group 1 at TP1 were negatively correlated with the pain degree at TP1 and TP2 (r = -0.549, -0.453; p = 0.012, 0.045). The Reho values of the middle temporal gyrus in Group 1 at TP3 were negatively correlated with the changes of clinical scale scores between TP3 and TP1 (r = 0.454, 0.559; p = 0.044, 0.01).

CONCLUSION

Patients with CLBP showed abnormal brain function activity, which was altered after SMT. The Reho values of the left precuneus could predict the immediate analgesic effect of SMT.

Evidence for increased neuromuscular drive following spinal manipulation in individuals with subacromial pain syndrome

BACKGROUND

Thoracic spinal manipulation can improve pain and function in individuals with shoulder pain; however, the mechanisms underlying these benefits remain unclear. Here, we evaluated the effects of thoracic spinal manipulation on muscle activity, as alteration in muscle activity is a key impairment for those with shoulder pain. We also evaluated the relationship between changes in muscle activity and clinical outcomes, to characterize the meaningful context of a change in neuromuscular drive.

METHODS

Participants with shoulder pain related to subacromial pain syndrome (n = 28) received thoracic manipulation of low amplitude high velocity thrusts to the lower, middle and upper thoracic spine. Electromyographic muscle activity (trapezius-upper, middle, lower; serratus anterior; deltoid; infraspinatus) and shoulder pain (11-point scale) was collected pre and post-manipulation during arm elevation, and normalized to a reference contraction. Clinical benefits were assessed using the Pennsylvania Shoulder Score (Penn) at baseline and 2-3 days post-intervention.

FINDINGS

A significant increase in muscle activity was observed during arm ascent (p = 0.002). Using backward stepwise regression analysis, a specific increase in the serratus anterior muscle activity during arm elevation explained improved Penn scores following post-manipulation (p < 0.05).

INTERPRETATION

Thoracic spinal manipulation immediately increases neuromuscular drive. In addition, increased serratus anterior muscle activity, a key muscle for scapular motion, is associated with short-term improvements in shoulder clinical outcomes.

Segmental Chiropractic Spinal Manipulation Does not Reduce Pain Amplification and the Associated Pain-Related Brain Activity in a Capsaicin-Heat Pain Model

Musculoskeletal injuries lead to sensitization of nociceptors and primary hyperalgesia (hypersensitivity to painful stimuli). This occurs with back injuries, which are associated with acute pain and increased pain sensitivity at the site of injury. In some cases, back pain persists and leads to central sensitization and chronic pain. Thus, reducing primary hyperalgesia to prevent central sensitization may limit the transition from acute to chronic back pain. It has been shown that spinal manipulation (SM) reduces experimental and clinical pain, but the effect of SM on primary hyperalgesia and hypersensitivity to painful stimuli remains unclear. The goal of the present study was to investigate the effect of SM on pain hypersensitivity using a capsaicin-heat pain model. Laser stimulation was used to evoke heat pain and the associated brain activity, which were measured to assess their modulation by SM. Eighty healthy participants were recruited and randomly assigned to one of the four experimental groups: inert cream and no intervention; capsaicin cream and no intervention; capsaicin cream and SM at T7; capsaicin cream and placebo. Inert or capsaicin cream (1%) was applied to the T9 area. SM or placebo were performed 25 min after cream application. A series of laser stimuli were delivered on the area of cream application (1) before cream application, (2) after cream application but before SM or placebo, and (3) after SM or placebo. Capsaicin cream induced a significant increase in laser pain (p < 0.001) and laser-evoked potential amplitude (p < 0.001). However, SM did not decrease the amplification of laser pain or laser-evoked potentials by capsaicin. These results indicate that segmental SM does not reduce pain hypersensitivity and the associated pain-related brain activity in a capsaicin-heat pain model.

Thoracic Spinal Manipulation Effect on Neuroendocrine Response in People With Achilles Tendinopathy: A Randomized Crossover Trial

OBJECTIVE

The purpose of the present study was to determine the neuroendocrine response after a thoracic spinal manipulation in people with Achilles tendinopathy.

METHODS

This was a randomized 2-sequence, 2-period crossover trial. A total of 24 participants, mean (standard deviation) age of 48 (7) years, with a diagnosis of Achilles tendinopathy (>3 mo) were randomly assigned into sequence 1 (sham intervention and then thoracic spinal manipulation) or sequence 2 (thoracic spinal manipulation and then sham intervention). The trial was conducted at a university laboratory with a washout period of 1 week. The primary outcome measure was the testosterone/cortisol (T/C) ratio (salivary samples). The secondary outcome measures included heart rate variability (measured with electrocardiography) and total oxygenation index (nmol/L) of calf muscle and Achilles tendon (measured with near-infrared spectroscopy). A 2-way mixed-model analysis of variance was performed. The statistic of interest was the condition by time interaction.

RESULTS

A statistically significant condition by time interaction was found for the T/C ratio (mean difference: -0.16; confidence interval: -0.33 to 0.006; interaction: P < .05) and the total oxygenation index (mean difference: 1.35; confidence interval: -1.3 to 4.1; interaction: P < .05) of calf muscle but not for Achilles tendon (P = .6); however, no difference was found for heart rate variability (P = .5).

CONCLUSION

In people with Achilles tendinopathy, thoracic spinal manipulation resulted in immediate increase in the total oxygenation index in the calf muscle followed by an increase in the T/C ratio 6 hours post-intervention.

Increased Salience Network Connectivity Following Manual Therapy is Associated with Reduced Pain in Chronic Low Back Pain Patients

Chronic low back pain (cLBP) has been associated with changes in brain plasticity. Nonpharmacological therapies such as Manual Therapy (MT) have shown promise for relieving cLBP. However, translational neuroimaging research is needed to understand potential central mechanisms supporting MT. We investigated the effect of MT on resting-state salience network (SLN) connectivity, and whether this was associated with changes in clinical pain. Fifteen cLBP patients, and 16 matched healthy controls (HC) were scanned with resting functional Magnetic Resonance Imaging (fMRI), before and immediately after a MT intervention (cross-over design with two separate visits, pseudorandomized, grades V 'Manipulation' and III 'Mobilization' of the Maitland Joint Mobilization Grading Scale). Patients rated clinical pain (0-100) pre- and post-therapy. SLN connectivity was assessed using dual regression probabilistic independent component analysis. Both manipulation (Pre: 39.43 ± 16.5, Post: 28.43 ± 16.5) and mobilization (Pre: 38.83 ± 17.7, Post: 31.76 ± 19.4) reduced clinical back pain (P < .05). Manipulation (but not mobilization) significantly increased SLN connectivity to thalamus and primary motor cortex. Additionally, a voxelwise regression indicated that greater MT-induced increase in SLN connectivity to the lateral prefrontal cortex was associated with greater clinical back pain reduction immediately after intervention, for both manipulation (r = -0.8) and mobilization (r = -0.54). Our results suggest that MT is successful in reducing clinical low back pain by both spinal manipulation and spinal mobilization. Furthermore, this reduction post-manipulation occurs via modulation of SLN connectivity to sensorimotor, affective, and cognitive processing regions. PERSPECTIVE: MT both reduces clinical low back pain and modulates brain activity important for the processing of pain. This modulation was shown by increased functional brain connectivity between the salience network and brain regions involved in cognitive, affective, and sensorimotor processing of pain.

The Association Between Conditioned Pain Modulation and Manipulation-induced Analgesia in People With Lateral Epicondylalgia

OBJECTIVES

Conditioned pain modulation (CPM) and manipulation-induced analgesia (MIA) may activate similar neurophysiological mechanisms to mediate their analgesic effects. This study assessed the association between CPM and MIA responses in people with lateral epicondylalgia.

MATERIALS AND METHODS

Seventy participants with lateral epicondylalgia were assessed for CPM followed by MIA. A single assessor measured pressure pain thresholds (PPT) before, during, and after cold water immersion (10°C) of the asymptomatic hand and contralateral lateral glide (CLG) mobilization of the neck. For analyses, linear mixed models evaluated differences in CPM and MIA responses. Pearson partial correlations and regression analyses evaluated the association between CPM and MIA PPT.

RESULTS

There was a significant increase (CPM and MIA, P<0.001) in PPT from baseline during the interventions (CPM mean: 195.84 kPa for elbow and 201.87 kPa for wrist, MIA mean: 123.01 kPa for elbow and 126.06 kPa for wrist) and after the interventions (CPM mean: 126.06 kPa for elbow, 114.24 kPa for wrist, MIA mean: 123.50 kPa for elbow and 122.16 kPa for wrist). There were also significant moderate and positive partial linear correlations (r: 0.40 to 0.54, P<0.001) between CPM and MIA measures, controlling for baseline measures. Regression analyses showed that CPM PPT was a significant predictor of MIA PPT (P<0.001) and the models explained between 73% and 85% of the variance in MIA PPT.

DISCUSSION

This study showed that CPM and MIA responses were significantly correlated and that the CPM response was a significant predictor of MIA response.

Evidence for decreased Neurologic Pain Signature activation following thoracic spinal manipulation in healthy volunteers and participants with neck pain

•

The use of brain-based models of pain were explored in two clinical studies.

•

Neurologic pain signature activation decreased following spinal manipulation.

•

Spinal manipulation altered the processing of pain-related brain activity.

•

We provide evidence for a centrally mediated therapeutic action of spinal manipulation.

•

Brain-based models have potential as objective clinical biomarkers of pain.

Background Context

Spinal manipulation (SM) is a common treatment for neck and back pain, theorized to mechanically affect the spine leading to therapeutic mechanical changes. The link between specific mechanical effects and clinical improvement is not well supported. SM's therapeutic action may instead be partially mediated within the central nervous system.

Purpose

To introduce brain-based models of pain for spinal pain and manual therapy research, characterize the distributed central mechanisms of SM, and advance the preliminary validation of brain-based models as potential clinical biomarkers of pain.

Study Design

Secondary analysis of two functional magnetic resonance imaging studies investigating the effect of thoracic SM on pain-related brain activity: A non-controlled, non-blinded study in healthy volunteers (Study 1, n = 10, 5 females, and mean age = 31.2 ± 10.0 years) and a randomized controlled study in participants with acute to subacute neck pain (Study 2, n = 24, 16 females, mean age = 38.0 ± 15.1 years).

Methods

Functional magnetic resonance imaging was performed during noxious mechanical stimulation of the right index finger cuticle pre- and post-intervention. The effect of SM on pain-related activity was studied within brain regions defined by the Neurologic Pain Signature (NPS) that are predictive of physical pain.

Results

In Study 1, evoked mechanical pain (p < 0.001) and NPS activation (p = 0.010) decreased following SM, and the changes in evoked pain and NPS activation were correlated (r_RM² = 0.418, p = 0.016). Activation within the NPS subregions of the dorsal anterior cingulate cortex (dACC, p = 0.012) and right secondary somatosensory cortex/operculum (rS2_Op, p = 0.045) also decreased following SM, and evoked pain was correlated with dACC activity (r_RM² = 0.477, p = 0.019). In Study 2, neck pain (p = 0.046) and NPS (p = 0.033) activation decreased following verum but not sham SM. Associations between evoked pain, neck pain, and NPS activation, were not significant and less clear, possibly due to inadequate power, methodological limitations, or other confounding factors.

Conclusions

The findings provide preliminary evidence that SM may alter the processing of pain-related brain activity within specific pain-related brain regions and support the use of brain-based models as clinical biomarkers of pain.

Cerebral Perfusion Changes After Osteopathic Manipulative Treatment: A Randomized Manual Placebo-Controlled Trial

Osteopathic Manipulative Treatment (OMT) is a therapeutic approach aimed at enhancing the body's self-regulation focusing on somatic dysfunctions correction. Despite evidence of OMT effectiveness, the underlying neurophysiological mechanisms, as well as blood perfusion effects, are still poorly understood. The study aim was to address OMT effects on cerebral blood flow (CBF) in asymptomatic young volunteers as measured by Magnetic Resonance Arterial Spin Labeling (ASL) method. Thirty blinded participants were randomized to OMT or placebo, and evaluated with an MRI protocol before manual intervention (T0), immediately after (T1), and 3 days later (T2). After T0 MRI, participants received 45 min of OMT, focused on correcting whole body somatic dysfunctions, or placebo manual treatment, consisting of passive touches in a protocolled order. After treatment, participants completed a de-blinding questionnaire about treatment perception. Results show significant differences due to treatment only for the OMT group (OMTg): perfusion decreased (compared to T0) in a cluster comprising the left posterior cingulate cortex (PCC) and the superior parietal lobule, while increased at T2 in the contralateral PCC. Furthermore, more than 60% of participants believed they had undergone OMT. The CBF modifications at T2 suggest that OMT produced immediate but reversible effects on CBF.

Functional Magnetic Resonance Imaging of Cerebral Hemodynamic Responses to Pain Following Thoracic Thrust Manipulation in Individuals With Neck Pain: A Randomized Trial

OBJECTIVE

The purpose of this study was to examine whether cerebral activation in response to noxious mechanical stimuli varies with thrust manipulation (TM) when compared with sham manipulation (SM) as measured by blood oxygenation level-dependent functional magnetic resonance imaging.

METHODS

Twenty-four volunteers (67% female) with complaints of acute or subacute mechanical (nontraumatic) neck pain satisfied eligibility requirements and agreed to participate. Participants were randomized to receive TM to the thoracic spine or SM, and then underwent functional magnetic resonance scanning while receiving noxious stimuli before and after TM or SM. An 11-point numeric pain rating scale was administered pre- and postmanipulation for neck pain and to determine perceptions of pain intensity with respect to neck pain and mechanical stimuli. Blood oxygenation level-dependent functional magnetic resonance imaging recorded the cerebral hemodynamic response to the mechanical stimuli.

RESULTS

Imaging revealed significant group differences, with those individuals in the manipulation group exhibiting increased areas of activation (postmanipulation) in the insular and somatosensory cortices and individuals in the sham group exhibiting greater areas of activation in the precentral gyrus, supplementary motor area, and cingulate cortices (P < .05). However, between-group differences on the numeric pain rating scale for mechanical stimuli and for self-reported neck pain were not statistically significant.

CONCLUSIONS

This study provides preliminary level 2b evidence suggesting cortical responses in patients with nontraumatic neck pain may vary between thoracic TM and a sham comparator.

The immediate and 1-week effects of mid-thoracic thrust manipulation on lower extremity passive range of motion

BACKGROUND

Research suggests that spinal manipulation may effect motion. Less clear is whether this effect is limited to localized responses or may involve generalizable changes. Objective: To determine whether Mid-thoracic manipulation (MTM) would result in a significant change in the lower extremity passive straight leg raise (PSLR) range of motion immediately and after 1 week. Methods: Twenty-three healthy subjects were randomly assigned in a double-blinded study. An experimental group received MTM and a control group received a sham intervention. PSLR measurements were taken prior to, immediately after, and one week after the intervention. Results: Mixed model repeated measure analysis of variance was used to determine that there was a significant interaction between MTM and time (F(2, 21) = 3.84, p < 0.05). Post hoc tests revealed a significant difference between the pretest to immediate posttest values (p < 0.05, SE = 1.47). PSLR in the MTM group increased 10.3° while the sham group increased 1.9°. Difference was non-significant between pretest and 1-week follow-up (p = 0.129, SE = 2.46). Conclusions: MTM may immediately increase lower extremity passive range of motion, but the effect was lost by the 1-week follow-up. This supports evolving research suggesting that spinal manipulation may have a generalized but transient physiological effect.

Immediate Effects of Thoracic Spine Thrust Manipulation on Neurodynamic Mobility

OBJECTIVE

The purpose of this study was to investigate the immediate effects of thoracic spine thrust manipulation (TSM) on the upper limb provocation test (ULPT) and seated slump test (SST) in individuals with identified neurodynamic mobility impairments. A secondary aim was to determine if correlation existed between the perception of effect and improvements in neurodynamic mobility following a thrust manipulation compared with mobilization.

METHODS

A pretest-posttest experimental design randomized 48 adults into 2 groups: TSM or mobilization. Participants with identified neurodynamic mobility impairment as assessed with the ULPT or SST received a pre-assigned intervention (TSM, n = 64 limbs; mobilization, n = 66 limbs). Perception of effect was assessed to determine its influence on outcome. Repeated-measures analysis of variance was used to examine the effects of intervention, and Fisher's exact test and independent t tests were used to determine the influence of perception.

RESULTS

Both the ULPT (P < .001) and SST (P < .001) revealed improvements at posttest regardless of intervention. The ULPT effect sizes for TSM (d = 0.70) and mobilization (d = 0.69) groups were medium. For the SST, the effect size for the TSM group (d = 0.53) was medium, whereas that for the mobilization group (d = 0.26) was small. Participants in the mobilization group with positive perception had significantly greater (P < .05) mean neurodynamic mobility changes than those with a negative perception.

CONCLUSIONS

Neurodynamic mobility impairment improved regardless of intervention. The magnitude of change was greater in the ULPT than SST. Although both interventions appeared to yield similar outcomes, individuals who received mobilization and expressed a positive perception of effect exhibited significantly greater changes in neurodynamic mobility than those without a positive perception.

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.

Differential efficiency of transcutaneous electrical nerve stimulation in dominant versus nondominant hands in fibromyalgia: placebo-controlled functional near-infrared spectroscopy study

Using functional near-infrared spectroscopy (fNIRS), modulation of hemodynamic responses by transcutaneous electrical nerve stimulation (TENS) during delivery of nociceptive stimulation was investigated in fibromyalgia (FM) patients and healthy controls for both hands. Two experiments were conducted: (1) median nerve stimulation with TENS and (2) painful stimulation using electronic von Frey filaments with TENS/placebo TENS. Mean [Formula: see text] brain activity was compared across groups and conditions using factorial ANOVA. Dominant (right) hand stimulation indicated significant interactions between group and condition in both hemispheres. Post hoc results revealed that FM patients showed an increased activation in "pain + TENS" condition compared to the "pain + placebo TENS" condition while the brain activity patterns for these conditions in controls were reversed. Left-hand stimulation resulted in similar TENS effects (reduced activation for "pain + TENS" than "pain + placebo TENS") in both groups. TENS effects in FM patients might be manipulated by the stimulation side. While the nondominant hand was responsive to TENS treatment, the dominant hand was not. These results indicate that stimulation side might be an effective factor in FM treatment by using TENS. Future studies are needed to clarify the underlying mechanism for these findings.

Comparison of 2 Lumbar Manual Therapies on Temporal Summation of Pain in Healthy Volunteers

The purpose of this study was to compare the immediate change in temporal summation of heat pain (TSP) between spinal manipulation (SMT) and spinal mobilization (MOB) in healthy volunteers. Ninety-two volunteers (24 male; 23.8 ± 5.3 years) were randomized to receive SMT, MOB, or no treatment (REST) for 1 session. Primary outcomes were changes in TSP, measured at the hand and foot, immediately after the session. A planned subgroup analysis investigated effects across empirically derived TSP clusters. For the primary outcome there were no differences in the immediate change in TSP measured at the foot between SMT and MOB, however, both treatments were superior to the REST condition. In the subgroup analysis the response to a standard TSP protocol was best characterized by 3 clusters: 52% no change (n = 48, 52%); facilitatory response (n = 24, 26%), and inhibitory response (n = 20, 22%). There was a significant Time × Treatment group × Cluster interaction for TSP measured at the foot. The inhibitory cluster showed the greatest attenuation of TSP after SMT and MOB compared with REST. These data suggest lumbar manual therapies of different velocities produce a similar localized attenuation of TSP, compared with no treatment. Attenuation of localized pain facilitatory processes by manual therapies was greatest in pain-free individuals who show an inhibitory TSP response.

PERSPECTIVE

The attenuation of pain facilitatory measures may serve an important underlying role in the therapeutic response to manual therapies. Identifying patients in pain who still have an inhibitory capacity (ie, an inhibitory response subgroup) may be useful clinically in identifying the elusive "manual therapy" responder.

Decreased spontaneous activity and altered evoked nociceptive response of rat thalamic submedius neurons to lumbar vertebra thrust

The thalamus is a central structure important to modulating and processing all mechanoreceptor input destined for the cortex. A large number of diverse mechanoreceptor endings are stimulated when a high velocity low amplitude thrust is delivered to the lumbar spine during spinal manipulation. The objective of this study was to determine if a lumbar thrust alters spontaneous and/or evoked nociceptive activity in medial thalamic submedius (Sm) neurons. Extracellular recordings were obtained from 94 thalamic Sm neurons in 54 urethane-anesthetized adult Wistar rats. Spontaneous activity was recorded 5 min before and after an L₅ control (no thrust) and thrust (85% rat body weight; 100 ms) procedure. In a subset of responsive nociceptive-specific neurons, mean changes in noxious-evoked response (10-s pinch with clip; 795 g) at three sites (tail, contra- and ipsilateral hindpaw) were determined following an L₅ thrust. Mean changes in Sm spontaneous activity (60 s bins) and evoked noxious response were compared using a mixed model repeated measures ANOVA with Bonferroni post hoc t tests and paired t tests, respectively. Compared to control, spontaneous Sm activity decreased 180-240 s following the lumbar thrust (p < 0.005). Inhibitory evoked responses were attenuated in the contralateral hindpaw following an L₅ thrust compared to control (p < 0.05). No other changes in spontaneous or noxious-evoked Sm activity were found. A delayed, but prolonged suppression of spontaneous Sm activity along with changes in noxious-evoked inhibitory responses in the contralateral hindpaw following lumbar vertebra thrust suggest that thalamic submedius neurons may play a role in central pain modulation related to manual therapy intervention.

Measuring Pain for Patients Seeking Physical Therapy: Can Functional Magnetic Resonance Imaging (fMRI) Help?

In the multidisciplinary fields of pain medicine and rehabilitation, advancing techniques such as functional magnetic resonance imaging (fMRI) are used to enhance our understanding of the pain experience. Given that such measures, in some circles, are expected to help us understand the brain in pain, future research in pain measurement is undeniably rich with possibility. However, pain remains intensely personal and represents a multifaceted experience, unique to each individual; no single measure in isolation, fMRI included, can prove or quantify its magnitude beyond the patient self-report. Physical therapists should be aware of cutting-edge advances in measuring the patient's pain experience, and they should work closely with professionals in other disciplines (eg, magnetic resonance physicists, biomedical engineers, radiologists, psychologists) to guide the exploration and development of multimodal pain measurement and management on a patient-by-patient basis. The primary purpose of this perspective article is to provide a brief overview of fMRI and inform physical therapist clinicians of the pros and cons when utilized as a measure of the patient's perception of pain. A secondary purpose is to describe current known factors that influence the quality of fMRI data and its analyses, as well as the potential for future clinical applications relevant to physical therapist practice. Lastly, the interested reader is introduced and referred to existing guidelines and recommendations for reporting fMRI research.

The effect of manual therapy and neuroplasticity education on chronic low back pain: a randomized clinical trial

Objective

To determine if a neuroplasticity educational explanation for a manual therapy technique will produce a different outcome compared to a traditional mechanical explanation.

Methods

Sixty-two patients with chronic low back pain (CLBP) were recruited for the study. Following consent, demographic data were obtained as well as pain ratings for low back pain (LBP) and leg pain (Numeric Pain Rating Scale), disability (Oswestry Disability Index), fear-avoidance (Fear-Avoidance-Beliefs Questionnaire), forward flexion (fingertips-to-floor), and straight leg raise (SLR) (inclinometer). Patients were then randomly allocated to receive one of two explanations (neuroplasticity or mechanical), a manual therapy technique to their lumbar spine, followed by post-intervention measurements of LBP, leg pain, forward flexion, and SLR.

Results

Sixty-two patients (female 35 [56.5%]), with a mean age of 60.1 years and mean duration of 9.26 years of CLBP participated in the study. There were no statistically significant interactions for LBP (p = .325), leg pain (p = .172), and trunk flexion (p = .818) between the groups, but SLR showed a significant difference in favor of the neuroplasticity explanation (p = .041). Additionally, the neuroplasticity group were 7.2 times (95% confidence interval = 1.8-28.6) more likely to improve beyond the MDC on the SLR than participants in the mechanical group.

Discussion

The results of this study show that a neuroplasticity explanation, compared to a traditional biomechanical explanation, resulted in a measureable difference in SLR in patients with CLBP when receiving manual therapy. Future studies need to explore if the increase in SLR correlated to changes in cortical maps of the low back.

The evolving role of physical therapists in the long-term management of chronic low back pain: longitudinal care using assisted self-management strategies

Background

Longitudinal studies have shown that the symptoms of chronic low back pain (CLBP) will follow an episodic trajectory characterized by periods of high and low pain intensity that can persist for many years. There is a growing belief that the contemporary approach of limiting physical therapy to short, but intense courses of treatment for (CLBP) may be sub-optimal because these limited “windows” of clinical care are not congruent with the natural history of this condition. Recent research has suggested that people with CLBP undergo substantial, and individualized long-term variations in the neural processing of nociception over time. This has led to the concept of a “unique biosignature of pain” that may explain much of the variation in a person’s clinical picture. These and other findings have led to the reconceptualization of CLBP as an individualized, and continually evolving condition that may be more suitably managed by empowering the patient toward self-management strategies that can be modified as needed over time by the PT.

Objectives

The purpose of this Master Class Paper is to describe an emerging approach for the treatment of CLBP that emphasizes the formation of a long-term therapeutic alliance between the patient and the PT with an emphasis on individualized, patient-preferred approaches for activity-based self-management as an alternative to the contemporary approach of short, intense episodes of care directed toward pain reduction.

Conclusion

Longitudinal care using assisted self-management strategies is more congruent with the natural history of CLBP than are traditional approaches for PT intervention. This approach may empower patients to undergo lifestyle changes that will favorably influence long-term outcomes; however additional research is needed.

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.

Regional interdependence and manual therapy directed at the thoracic spine

Thoracic spine manipulation is commonly used by physical therapists for the management of patients with upper quarter pain syndromes. The theoretical construct for using thoracic manipulation for upper quarter conditions is a mainstay of a regional interdependence (RI) approach. The RI concept is likely much more complex and is perhaps driven by a neurophysiological response including those related to peripheral, spinal cord and supraspinal mechanisms. Recent evidence suggests that thoracic spine manipulation results in neurophysiological changes, which may lead to improved pain and outcomes in individuals with musculoskeletal disorders. The intent of this narrative review is to describe the research supporting the RI concept and its application to the treatment of individuals with neck and/or shoulder pain. Treatment utilizing both thrust and non-thrust thoracic manipulation has been shown to result in improvements in pain, range of motion and disability in patients with upper quarter conditions. Research has yet to determine optimal dosage, techniques or patient populations to which the RI approach should be applied; however, emerging evidence supporting a neurophysiological effect for thoracic spine manipulation may negate the need to fully answer this question. Certainly, there is a need for further research examining both the clinical efficacy and effectiveness of manual therapy interventions utilized in the RI model as well as the neurophysiological effects resulting from this intervention.

Efficacy of musculoskeletal manual approach in the treatment of temporomandibular joint disorder: A systematic review with meta-analysis

BACKGROUND

Temporomandibular joint disorder (TMD) requires a complex diagnostic and therapeutic approach, which usually involves a multidisciplinary management. Among these treatments, musculoskeletal manual techniques are used to improve health and healing.

OBJECTIVES

To assess the effectiveness of musculoskeletal manual approach in temporomandibular joint disorder patients.

DESIGN

A systematic review with meta-analysis.

METHODS

During August 2014 a systematic review of relevant databases (PubMed, The Cochrane Library, PEDro and ISI web of knowledge) was performed to identify controlled clinical trials without date restriction and restricted to the English language. Clinical outcomes were pain and range of motion focalized in temporomandibular joint. The mean difference (MD) or standard mean difference (SMD) with 95% confidence intervals (CIs) and overall effect size were calculated at every post treatment. The PEDro scale was used to demonstrate the quality of the included studies.

RESULTS/FINDINGS

From the 308 articles identified by the search strategy, 8 articles met the inclusion criteria. The meta-analysis showed a significant difference (p < 0.0001) and large effect on active mouth opening (SMD, 0.83; 95% CI, 0.42 to 1.25) and on pain during active mouth opening (MD, 1.69; 95% CI, 1.09 to 2.30) in favor of musculoskeletal manual techniques when compared to other conservative treatments for TMD.

CONCLUSIONS

Musculoskeletal manual approaches are effective for treating TMD. In the short term, there is a larger effect regarding the latter when compared to other conservative treatments for TMD.

Improving long-term outcomes for chronic low back pain: time for a new paradigm?

These are exciting times for physical therapists who treat people with chronic low back pain (CLBP). Many of the mysteries of this condition are starting to be revealed, and it appears that major breakthroughs are on the way. Advances in neuroimaging, coupled with increased understanding of the molecular and submolecular events associated with the symptoms of back pain, are helping us reconceptualize the etiologies and mechanisms of this condition. The result of these advances is that physical therapists now have a wide range of potential "treatment packages" that can include patient education, manual therapy, and a wide variety of exercise options for people with CLBP. The question is, "How can long-term, self-management programs become more effective?"

Immediate changes after manual therapy in resting-state functional connectivity as measured by functional magnetic resonance imaging in participants with induced low back pain

OBJECTIVE

The purposes of this study were to use functional magnetic resonance imaging to investigate the immediate changes in functional connectivity (FC) between brain regions that process and modulate the pain experience after 3 different types of manual therapies (MT) and to identify reductions in experimentally induced myalgia and changes in local and remote pressure pain sensitivity.

METHODS

Twenty-four participants (17 men; mean age ± SD, 21.6 ± 4.2 years) who completed an exercise-injury protocol to induce low back pain were randomized into 3 groups: chiropractic spinal manipulation (n = 6), spinal mobilization (n = 8), or therapeutic touch (n = 10). The primary outcome was the immediate change in FC as measured on functional magnetic resonance imaging between the following brain regions: somatosensory cortex, secondary somatosensory cortex, thalamus, anterior and posterior cingulate cortices, anterior and poster insula, and periaqueductal gray. Secondary outcomes were immediate changes in pain intensity, measured with a 101-point numeric rating scale, and pain sensitivity, measured with a handheld dynamometer. Repeated-measures analysis of variance models and correlation analyses were conducted to examine treatment effects and the relationship between within-person changes across outcome measures.

RESULTS

Changes in FC were found between several brain regions that were common to all 3 MT interventions. Treatment-dependent changes in FC were also observed between several brain regions. Improvement was seen in pain intensity after all interventions (P < .05) with no difference between groups (P > .05). There were no observed changes in pain sensitivity, or an association between primary and secondary outcome measures.

CONCLUSION

These results suggest that MTs (chiropractic spinal manipulation, spinal mobilization, and therapeutic touch) have an immediate effect on the FC between brain regions involved in processing and modulating the pain experience. This suggests that neurophysiologic changes after MT may be an underlying mechanism of pain relief.

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.