Patient-centered outcomes of high-velocity, low-amplitude spinal manipulation for low back pain: A systematic review

Mechanisms of manipulation: a systematic review of the literature on immediate anatomical structural or positional changes in response to manually delivered high-velocity, low-amplitude spinal manipulation

BACKGROUND

Spinal manipulation (SM) has been claimed to change anatomy, either in structure or position, and that these changes may be the cause of clinical improvements. The aim of this systematic review was to evaluate and synthesise the peer-reviewed literature on the current evidence of anatomical changes in response to SM.

METHODS

The review was registered with PROSPERO (CRD42022304971) and reporting was guided by the standards of the PRISMA Statement. We searched Medline, Embase, CINAHL, AMED, Cochrane Library all databases, PEDro, and the Index to Chiropractic Literature from inception to 11 March 2022 and updated on 06 June 2023. Search terms included manipulation, adjustment, chiropractic, osteopathy, spine and spine-related structures. We included primary research studies that compared outcomes with and without SM regardless of study design. Manipulation was defined as high-velocity, low-amplitude thrust delivered by hand to the spine or directly related joints. Included studies objectively measured a potential change in an anatomical structure or in position. We developed a novel list of methodological quality items in addition to a short, customized list of risk of bias (RoB) items. We used quality and RoB items together to determine whether an article was credible or not credible. We sought differences in outcomes between SM and control groups for randomised controlled trials and crossover studies, and between pre- and post-SM outcomes for other study designs. We reported, in narrative form, whether there was a change or not.

RESULTS

The search retrieved 19,572 articles and 20 of those were included for review. Study topics included vertebral position (n = 3) facet joint space (n = 5), spinal stiffness (n = 3), resting muscle thickness (n = 6), intervertebral disc pressure (n = 1), myofascial hysteresis (n = 1), and further damage to already damaged arteries (n = 1). Eight articles were considered credible. The credible articles indicated that lumbar facet joint space increased and spinal stiffness decreased but that the resting muscle thickness did not change.

CONCLUSION

We found few studies on this topic. However, there are two promising areas for future study: facet joint space and spinal stiffness. A research strategy should be developed with funding for high quality research centres.

Expectations affect pain sensitivity changes during massage

BACKGROUND

Pain-inducing massage produces comparable changes in pain sensitivity as a cold pressor task, suggesting shared neurophysiological mechanisms of conditioned pain modulation. Manual therapy and conditioned pain modulation are influenced by positive and negative expectations. Therefore, the purpose of this study was to examine the effects of positive and negative expectations on pain-free and pain-inducing massage.

METHODS

56 healthy participants were randomly assigned to receive a positive or negative expectation instructional set followed by a pain-inducing or a pain-free massage. Pressure pain threshold (PPT) was measured followed by each interval of massage. A repeated measures ANCOVA controlling for post-randomization differences in sex tested for massage x expectation set x PPT interaction effects, as well as two-way interaction effects.

RESULTS

A significant three-way interaction effect (p = 0.04) and time x expectation interaction effect was observed for individuals receiving pain inducing massage (p = 0.02). Individuals who received the positive expectation instructional set demonstrated significantly higher PPT at minutes 3 and 4 of massage compared to individuals who received the negative expectation instructional set.

CONCLUSIONS

Expectations impact pain sensitivity changes produced during massage. Clinicians planning to provide pain-inducing massage should consider the role of expectations in modulating pain sensitivity changes.

Thoracolumbar fascia mobility and chronic low back pain: Phase 2 of a pilot and feasibility study including multimodal chiropractic care

BACKGROUND

Thoracolumbar fascia mobility observed with ultrasound imaging and calculated as shear strain is lower in persons with chronic low back pain. This pilot and feasibility trial assessed thoracolumbar shear strain in persons with chronic low back pain following spinal manipulation and over an 8-week course of multimodal chiropractic care.

METHODS

Adults self-reporting chronic low back pain ≥ 1 year participated between September 2019 and April 2021 in a trial using ultrasound imaging to measure thoracolumbar shear strain. Ultrasound imaging occurred 2-3 cm lateral to L2-3 while participants relaxed prone on an automated table moving the lower extremities downward 15 degrees, for 5 cycles at 0.5 Hz. Pain intensity on an 11-point numerical rating scale, disability, pain interference, and global improvement were also collected. Participants received 8-weeks of twice-weekly chiropractic care including spinal manipulation, education, exercise, self-management advice and myofascial therapies. Shear strain was computed using 2 methods. The highest shear strain from movement cycles 2, 3, or 4 was averaged over right and left sides for each participant. Alternately, the highest shear strain from movement cycle 3 was used. All data were analyzed over time using mixed-effects models. Estimated mean changes are reported.

RESULTS

Of 20 participants completing 8-weeks of chiropractic care (female n = 11), mean (SD) age was 41 years (12.6); mean BMI was 28.5 (6.2). All clinical outcomes improved at 8-weeks. Mean (95% confidence interval) pain intensity decreased 2.7 points (- 4.1 to - 1.4) for females and 2.1 points (- 3.7 to 0.4) for males. Mean Roland-Morris disability score decreased by 5 points (- 7.2 to - 2.8) for females, 2.3 points (- 4.9 to 0.2) for males. Mean PROMIS pain interference T-score decreased by 8.7 points (- 11.8 to - 5.5) for females, 5.6 points (- 9.5 to - 1.6) for males. Mean shear strain at 8-weeks increased in females 5.4% (- 9.9 to 20.8) or 15% (- 0.5 to 30.6), decreasing in males 6.0% (- 24.2 to 12.2) or 2% (- 21.0 to 16.8) depending on computational method.

CONCLUSION

Spinal manipulation does not likely disrupt adhesions or relax paraspinal muscles enough to immediately affect shear strain. Clinical outcomes improved in both groups, however, shear strain only increased in females following 8-weeks of multimodal chiropractic care. Trial registration ClinicalTrials.gov registration is NCT03916705.

Evidence (-based medicine) in manual medicine/manual therapy—a summary review

Objective

The aim of this summary review is to analyse the current state of evidence in manual medicine or manual therapy.

Methods

The literature search focussed on systematic reviews listed in PubMed referring to manual medicine treatment until the beginning of 2022, limited to publications in English or German. The search concentrates on (1) manipulation, (2) mobilization, (3) functional/musculoskeletal and (4) fascia. The CASP Checklist for Systematic Reviews was used to present the included reviews in a clear way.

Results

A total of 67 publications were included and herewith five categories: low back pain, neck pain, extremities, temporomandibular disorders and additional effects. The results were grouped in accordance with study questions.

Conclusion

Based on the current systematic reviews, a general evidence-based medicine level III is available, with individual studies reaching level II or Ib. This allows manual medicine treatment or manual therapy to be used in a valid manner.

Formulation of Japanese Orthopaedic Association (JOA) clinical practice guideline for the management of low back pain- the revised 2019 edition

BACKGROUND

The latest clinical guidelines are mandatory for physicians to follow when practicing evidence-based medicine in the treatment of low back pain. Those guidelines should target not only Japanese board-certified orthopaedic surgeons, but also primary physicians, and they should be prepared based entirely on evidence-based medicine. The Japanese Orthopaedic Association Low Back Pain guideline committee decided to update the guideline and launched the formulation committee. The purpose of this study was to describe the formulation we implemented for the revision of the guideline with the latest data of evidence-based medicine.

METHODS

The Japanese Orthopaedic Association Low Back Pain guideline formulation committee revised the previous guideline based on a method for preparing clinical guidelines in Japan proposed by Medical Information Network Distribution Service Handbook for Clinical Practice Guideline Development 2014. Two key phrases, "body of evidence" and "benefit and harm balance" were focused on in the revised version. Background and clinical questions were determined, followed by literature search related to each question. Appropriate articles were selected from all the searched literature. Structured abstracts were prepared, and then meta-analyses were performed. The strength of both the body of evidence and the recommendation was decided by the committee members.

RESULTS

Nine background and nine clinical qvuestions were determined. For each clinical question, outcomes from the literature were collected and meta-analysis was performed. Answers and explanations were described for each clinical question, and the strength of the recommendation was decided. For background questions, the recommendations were described based on previous literature.

CONCLUSIONS

The 2019 clinical practice guideline for the management of low back pain was completed according to the latest evidence-based medicine. We strongly hope that this guideline serves as a benchmark for all physicians, as well as patients, in the management of low back pain.

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.

Veteran Response to Dosage in Chiropractic Therapy (VERDICT): Study Protocol of a Pragmatic Randomized Trial for Chronic Low Back Pain

BACKGROUND

Low back pain is a leading cause of disability in veterans. Chiropractic care is a well-integrated, nonpharmacological therapy in Veterans Affairs health care facilities, where doctors of chiropractic provide therapeutic interventions focused on the management of low back pain and other musculoskeletal conditions. However, important knowledge gaps remain regarding the effectiveness of chiropractic care in terms of the number and frequency of treatment visits needed for optimal outcomes in veterans with low back pain.

DESIGN

This pragmatic, parallel-group randomized trial at four Veterans Affairs sites will include 766 veterans with chronic low back pain who are randomly allocated to a course of low-dose (one to five visits) or higher-dose (eight to 12 visits) chiropractic care for 10 weeks (Phase 1). After Phase 1, participants within each treatment arm will again be randomly allocated to receive either monthly chiropractic chronic pain management for 10 months or no scheduled chiropractic visits (Phase 2). Assessments will be collected electronically. The Roland Morris Disability Questionnaire will be the primary outcome for Phase 1 at week 10 and Phase 2 at week 52.

SUMMARY

This trial will provide evidence to guide the chiropractic dose in an initial course of care and an extended-care approach for veterans with chronic low back pain. Accurate information on the effectiveness of different dosing regimens of chiropractic care can greatly assist health care facilities, including Veterans Affairs, in modeling the number of doctors of chiropractic that will best meet the needs of patients with chronic low back pain.

Extrapolating Beyond the Data in a Systematic Review of Spinal Manipulation for Nonmusculoskeletal Disorders: A Fall From the Summit

OBJECTIVE

The purpose of this article is to discuss a literature review-a recent systematic review of nonmusculoskeletal disorders-that demonstrates the potential for faulty conclusions and misguided policy implications, and to offer an alternate interpretation of the data using present models and criteria.

METHODS

We participated in a chiropractic meeting (Global Summit) that aimed to perform a systematic review of the literature on the efficacy and effectiveness of mobilization or spinal manipulative therapy (SMT) for the primary, secondary, and tertiary prevention and treatment of nonmusculoskeletal disorders. After considering an early draft of the resulting manuscript, we identified points of concern and therefore declined authorship. The present article was developed to describe those concerns about the review and its conclusions.

RESULTS

Three main concerns were identified: the inherent limitations of a systematic review of 6 articles on the topic of SMT for nonmusculoskeletal disorders, the lack of biological plausibility of collapsing 5 different disorders into a single category, and considerations for best practices when using evidence in policy-making. We propose that the following conclusion is more consistent with a review of the 6 articles. The small cadre of high- or moderate-quality randomized controlled trials reviewed in this study found either no or equivocal effects from SMT as a stand-alone treatment for infantile colic, childhood asthma, hypertension, primary dysmenorrhea, or migraine, and found no or low-quality evidence available to support other nonmusculoskeletal conditions. Therefore, further research is needed to determine if SMT may have an effect in these and other nonmusculoskeletal conditions. Until the results of such research are available, the benefits of SMT for specific or general nonmusculoskeletal disorders should not be promoted as having strong supportive evidence. Further, a lack of evidence cannot be interpreted as counterevidence, nor used as evidence of falsification or verification.

CONCLUSION

Based on the available evidence, some statements generated from the Summit were extrapolated beyond the data, have the potential to misrepresent the literature, and should be used with caution. Given that none of the trials included in the literature review were definitively negative, the current evidence suggests that more research on nonmusculoskeletal conditions is warranted before any definitive conclusions can be made. Governments, insurers, payers, regulators, educators, and clinicians should avoid using systematic reviews in decisions where the research is insufficient to determine the clinical appropriateness of specific care.

The Effect of Spinal Manipulation on the Electrophysiological and Metabolic Properties of the Tibialis Anterior Muscle

There is growing evidence showing that spinal manipulation increases muscle strength in healthy individuals as well as in people with some musculoskeletal and neurological disorders. However, the underlying mechanism by which spinal manipulation changes muscle strength is less clear. This study aimed to assess the effects of a single spinal manipulation session on the electrophysiological and metabolic properties of the tibialis anterior (TA) muscle. Maximum voluntary contractions (MVC) of the ankle dorsiflexors, high-density electromyography (HDsEMG), intramuscular EMG, and near-infrared spectroscopy (NIRS) were recorded from the TA muscle in 25 participants with low level recurring spinal dysfunction using a randomized controlled crossover design. The following outcomes: motor unit discharge rate (MUDR), strength (force at MVC), muscle conduction velocity (CV), relative changes in oxy- and deoxyhemoglobin were assessed pre and post a spinal manipulation intervention and passive movement control. Repeated measures ANOVA was used to assess within and between-group differences. Following the spinal manipulation intervention, there was a significant increase in MVC (p = 0.02; avg 18.87 ± 28.35%) and a significant increase in CV in both the isometric steady-state (10% of MVC) contractions (p < 0.01; avg 22.11 ± 11.69%) and during the isometric ramp (10% of MVC) contractions (p < 0.01; avg 4.52 ± 4.58%) compared to the control intervention. There were no other significant findings. The observed TA strength and CV increase, without changes in MUDR, suggests that the strength changes observed following spinal manipulation are, in part, due to increased recruitment of larger, higher threshold motor units. Further research needs to investigate the longer term and potential functional effects of spinal manipulation in various patients who may benefit from improved muscle function and greater motor unit recruitment.

Pain Education in the Context of Non-Specific Low Back Pain: The Lived Experience of the Physiotherapist. An Interpretive Phenomenological Analysis

OBJECTIVES

The aim of this study was to explore the physiotherapists' lived experiences of providing pain education (PE), to people living with non-specific low back pain (NSLBP). In previous studies, PE has been associated with positive clinical outcomes within the physiotherapeutic management of NSLBP. However, the meaning of providing PE, as experienced by physiotherapists, has not been specifically explored.

METHODS

This study adopted a hermeneutic phenomenological approach to explore PE experiences. Six semi-structured interviews were conducted, interviews were transcribed and analysed in line with the 'interpretative phenomenological analysis' framework.

RESULTS

Five main thematic meaning structures emerged: Experienced significance of assessment in understanding NSLBP, PE as explaining the nature of NSLBP, Experienced challenges in providing PE, individualisation as key to PE for NSLBP and Reassurance as central to PE for people living with NSLBP.

CONCLUSIONS

The significance of subjective assessment, was a key component of PE, as experienced by participants. However, differences were noted between participants in addressing the sense of assessment; in seeking a physiotherapeutic understanding of the NSLBP, and in seeking to understand the situation of those who are in pain. Within the participant experience, the significance of 'patient' reassurance was highlighted, related to the individualisation and outcome of PE. Reassurance, as described by participants, was emotive and practically grounded and linked with physical activity promotion. Individualisation in PE was meaningfully related to language modification and developing positive therapeutic relationships. Physiotherapists described PE particularly challenging related to pain chronicity and psychosocial factors, which may have significant implications to practice.

Immediate effects of a lumbar spine manipulation on pain sensitivity and postural control in individuals with nonspecific low back pain: a randomized controlled trial

Background

According to the American Physical Therapy Association, there is strong evidence to show that vertebral mobilization and manipulation procedures can be used to improve spinal and hip mobility and reduce pain and incapacity in low back pain patients that fit the clinical prediction rule. Objectives: To evaluate the immediate effects of high-velocity low-amplitude (HVLA) manipulation on pain and postural control parameters in individuals with nonspecific low back pain.

Methods

This study used a participant-blinded and assessor-blinded randomized controlled clinical trial involving a single session, in which 24 participants were randomly distributed into control (simulated manipulation) and intervention (HVLA lumbar manipulation) groups. The primary (pain: subjective pain intensity and pressure pain threshold) and secondary outcomes (postural control: ellipse area, center of pressure [COP] excursion, COP RMS velocity, and differences between the COP and center of projected gravity) were evaluated before and after the session using a numerical pain scale, algometer, and a force platform. For all outcomes, multiple mixed 2 (group) × 2 (time) ANOVAs were performed.

Results

For the subjective pain intensity, only time was significant as a main effect, where pre-intervention presented a greater value then post-intervention (F [1.44] = 4.377; p = 0.042; r = 0.30). For the pressure pain threshold no significant effect was found. For the postural control parameters, as a main effect, only the ellipse area was significantly greater in the control group (F [1.44] = 6.760; p = 0.013; effect size = 0.36).

Conclusions

There was a reduction in subjective pain intensity, evaluated using a numerical scale, in both the intervention and control groups immediately after the intervention, suggesting that the spinal manipulation had a similar effect to the placebo procedure. No effect of HVLA lumbar manipulation was identified for postural control variables in either the intervention or control groups.

Trial registration

The study was registered at ClinicalTrials.gov under the number NCT02312778, registered at 14 September 2014.

The effects of chiropractic spinal manipulation on central processing of tonic pain - a pilot study using standardized low-resolution brain electromagnetic tomography (sLORETA)

The objectives of the study were to investigate changes in pain perception and neural activity during tonic pain due to altered sensory input from the spine following chiropractic spinal adjustments. Fifteen participants with subclinical pain (recurrent spinal dysfunction such as mild pain, ache or stiffness but with no pain on the day of the experiment) participated in this randomized cross-over study involving a chiropractic spinal adjustment and a sham session, separated by 4.0 ± 4.2 days. Before and after each intervention, 61-channel electroencephalography (EEG) was recorded at rest and during 80 seconds of tonic pain evoked by the cold-pressor test (left hand immersed in 2 °C water). Participants rated the pain and unpleasantness to the cold-pressor test on two separate numerical rating scales. To study brain sources, sLORETA was performed on four EEG frequency bands: delta (1–4 Hz), theta (4–8 Hz), alpha (8–12 Hz) and beta (12–32 Hz). The pain scores decreased by 9% after the sham intervention (p < 0.05), whereas the unpleasantness scores decreased by 7% after both interventions (p < 0.05). sLORETA showed decreased brain activity following tonic pain in all frequency bands after the sham intervention, whereas no change in activity was seen after the chiropractic spinal adjustment session. This study showed habituation to pain following the sham intervention, with no habituation occurring following the chiropractic intervention. This suggests that the chiropractic spinal adjustments may alter central processing of pain and unpleasantness.

Stakeholder expectations from the integration of chiropractic care into a rehabilitation setting: a qualitative study

Background

Few studies have investigated patient and provider expectations of chiropractic care, particularly in multidisciplinary settings. This qualitative study explored stakeholder expectations of adding a chiropractor to the healthcare team at a rehabilitation specialty hospital.

Methods

The research methodology was an organizational case study with an inpatient facility for persons recovering from complex neurological conditions serving as the setting. Sixty stakeholders, including patients, families, hospital staff, and administrators, were interviewed or participated in focus groups in June 2015. Semi-structured questions guided the interview sessions which were digitally audiorecorded and transcribed. Data were entered into a qualitative software program to conduct content analysis using an iterative approach to identify key themes.

Results

Expectations for the chiropractic program were mostly positive with themes consistently reported across stakeholder groups. The central domain, making progress, encompassed the organizational mission to empower patients to reach hospital discharge and return to life in the community. Higher order goals, characterized as achieving whole person healing, encompassed patients’ quality of life, self-efficacy, and activities of daily living. Stakeholders expected the addition of chiropractic to help patients progress toward these goals by improving pain management and physical functioning. Pain management themes included pain intensity, medication use, and pain-related behaviors, while functional improvement themes included muscle tone, extremity function, and balance and mobility. In addition to these direct effects on clinical outcomes, stakeholders also expected indirect effects of chiropractic care on healthcare integration. This indirect effect was expected to increase patient participation in other providers’ treatments leading to improved care for the patient across the team and facility-level outcomes such as decreased length of stay.

Conclusions

Stakeholders expected the addition of chiropractic care to a rehabilitation specialty hospital to benefit patients through pain management and functional improvements leading to whole person healing. They also expected chiropractic to benefit the healthcare team by facilitating other therapies in pursuit of the hospital mission, that is, moving patients towards discharge. Understanding stakeholder expectations may allow providers to align current expectations with what may be reasonable, in an effort to achieve appropriate clinical outcomes and patient and staff satisfaction.

A Longitudinal Observational Clinical Study of Neurophysiological and Patient-Reported Responses to a Program of Physiotherapy for Acute and Subacute Low Back Pain

OBJECTIVES

The purpose of this study was to document the baseline neurophysiological status (skin conductance activity levels) of patients presenting for physiotherapy with acute and subacute low back pain (symptoms of up to 12 weeks' duration) and to observe the magnitude and direction of sympathetic nervous system (SNS) changes (skin conductance responses [SCRs]) occurring as a result of receiving guideline-endorsed physiotherapy treatment.

METHODS

A pragmatic, prospective, longitudinal, observational study recording SNS skin conductance (SC) responses and patient reported outcome measure changes to a program of guideline-endorsed physiotherapy treatment for low back pain symptoms of up to 12 weeks' duration. Sixty patients received a guideline-endorsed physiotherapy treatment program. Continuous neurophysiological recordings of SC activity levels were taken throughout each treatment. Patient reported outcome measure data were extracted from inception, midpoint, and discharge. Within and between treatment analyses determined the nature of SC changes and correlations to longitudinal changes in pain and function. Skin conductance changes were measured within and between treatment episodes at treatment inception, midpoint, and discharge and observed correlations between the magnitude of SCRs, pain abatement (numeric pain rating scale), and functional restoration (Oswestry Disability Index).

RESULTS

Skin conductance changes were significant during all "treatment" periods (P = .044), with the greatest magnitude of sympathoexcitatory responses occurring at inception (219%). The treatment modality providing the maximum SNS response was a high-velocity lumbar rotation manipulation. Positive correlations were identified between SCRs, Oswestry Disability Index improvements (r = 0.82, P < .0005), and pain abatement (r = 0.459, P < .0005).

CONCLUSIONS

Patients with low back pain exhibited neurophysiological treatment responses indicative of a symptom-related neuroplastic state of dorsal horn sensitization that may be receptive to early manual therapy intervention.

Effect of Usual Medical Care Plus Chiropractic Care vs Usual Medical Care Alone on Pain and Disability Among US Service Members With Low Back Pain: A Comparative Effectiveness Clinical Trial

IMPORTANCE

It is critically important to evaluate the effect of nonpharmacological treatments on low back pain and associated disability.

OBJECTIVE

To determine whether the addition of chiropractic care to usual medical care results in better pain relief and pain-related function when compared with usual medical care alone.

DESIGN, SETTING, AND PARTICIPANTS

A 3-site pragmatic comparative effectiveness clinical trial using adaptive allocation was conducted from September 28, 2012, to February 13, 2016, at 2 large military medical centers in major metropolitan areas and 1 smaller hospital at a military training site. Eligible participants were active-duty US service members aged 18 to 50 years with low back pain from a musculoskeletal source.

INTERVENTIONS

The intervention period was 6 weeks. Usual medical care included self-care, medications, physical therapy, and pain clinic referral. Chiropractic care included spinal manipulative therapy in the low back and adjacent regions and additional therapeutic procedures such as rehabilitative exercise, cryotherapy, superficial heat, and other manual therapies.

MAIN OUTCOMES AND MEASURES

Coprimary outcomes were low back pain intensity (Numerical Rating Scale; scores ranging from 0 [no low back pain] to 10 [worst possible low back pain]) and disability (Roland Morris Disability Questionnaire; scores ranging from 0-24, with higher scores indicating greater disability) at 6 weeks. Secondary outcomes included perceived improvement, satisfaction (Numerical Rating Scale; scores ranging from 0 [not at all satisfied] to 10 [extremely satisfied]), and medication use. The coprimary outcomes were modeled with linear mixed-effects regression over baseline and weeks 2, 4, 6, and 12.

RESULTS

Of the 806 screened patients who were recruited through either clinician referrals or self-referrals, 750 were enrolled (250 at each site). The mean (SD) participant age was 30.9 (8.7) years, 175 participants (23.3%) were female, and 243 participants (32.4%) were nonwhite. Statistically significant site × time × group interactions were found in all models. Adjusted mean differences in scores at week 6 were statistically significant in favor of usual medical care plus chiropractic care compared with usual medical care alone overall for low back pain intensity (mean difference, -1.1; 95% CI, -1.4 to -0.7), disability (mean difference, -2.2; 95% CI, -3.1 to -1.2), and satisfaction (mean difference, 2.5; 95% CI, 2.1 to 2.8) as well as at each site. Adjusted odd ratios at week 6 were also statistically significant in favor of usual medical care plus chiropractic care overall for perceived improvement (odds ratio = 0.18; 95% CI, 0.13-0.25) and self-reported pain medication use (odds ratio = 0.73; 95% CI, 0.54-0.97). No serious related adverse events were reported.

CONCLUSIONS AND RELEVANCE

Chiropractic care, when added to usual medical care, resulted in moderate short-term improvements in low back pain intensity and disability in active-duty military personnel. This trial provides additional support for the inclusion of chiropractic care as a component of multidisciplinary health care for low back pain, as currently recommended in existing guidelines. However, study limitations illustrate that further research is needed to understand longer-term outcomes as well as how patient heterogeneity and intervention variations affect patient responses to chiropractic care.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01692275.

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.

Neural Responses to Physical Characteristics of a High-velocity, Low-amplitude Spinal Manipulation: Effect of Thrust Direction

STUDY DESIGN

Electrophysiological recordings were obtained from proprioceptors in deep lumbar paraspinal muscles of anesthetized cats during high-velocity low-amplitude spinal manipulation (HVLA-SM).

OBJECTIVE

To determine how thrust direction of an HVLA-SM affects neural input from back musculature.

SUMMARY OF BACKGROUND DATA

A clinician's ability to apply the thrust of an HVLA-SM in a specified direction is considered an important component of its optimal delivery. However, previous biomechanical studies indicate that the shear force component of the thrust vector is not actually transmitted to paraspinal tissues deep to the thoracolumbar fascia because the skin-fascia interface is frictionless.

METHODS

Neural activity from muscle spindles in the multifidus and longissimus muscles was recorded from L6 dorsal rootlets in 18 anesthetized cats. After preload to the spinal tissues, HVLA-SMs (100-ms thrust duration) were applied through the intact skin overlying the L6 lamina. Thrusts were applied at angles oriented perpendicularly to the back and obliquely at 15° and 30° medialward or cranialward using a 6 × 6 Latin square design with three replicates. The normal force component was kept constant at 21.3 N. HVLA-SMs were preceded and followed by simulated spinal movement applied to the L6 vertebra. Changes in mean instantaneous discharge frequency (ΔMIF) of muscle spindles were determined both during the thrust and spinal movement.

RESULTS

ΔMIFs during the HVLA-SM thrust were significantly greater in response to all thrust directions compared with the preload alone, but there was no difference in ΔMIF for any of the thrust directions during the HVLA-SM. HVLA-SM decreased some of the responses to simulated spinal movement but thrust direction had no effect on these changes.

CONCLUSION

The shear force component of an HVLA-SM's thrust vector is not transmitted to the underlying vertebra sufficient to activate muscle spindles of the attached muscles. Implications for clinical practice and clinical research are discussed.

LEVEL OF EVIDENCE

N/A.

The Quality of Life of Children Under Chiropractic Care Using PROMIS-25: Results from a Practice-Based Research Network

OBJECTIVES

To characterize pediatric chiropractic and assess pediatric quality of life (QoL).

DESIGN

A prospective cohort. Setting/Locations: Individual offices within a practice-based research network located throughout the United States.

SUBJECTS

A convenience sample of children (8-17 years) under chiropractic care and their parents.

EXPOSURE

Chiropractic spinal adjustments and adjunctive therapies.

OUTCOME MEASURES

Survey instrument measuring sociodemographic information and correlates from the clinical encounter along with the Patient Reported Outcomes Measurement Information System (PROMIS)-25 to measure QoL (i.e., depression, anxiety, and pain interference). Sociodemographic and clinical correlates were analyzed using descriptive statistics (i.e., frequencies/percentages, means, and standard deviations). The PROMIS-25 data were analyzed using scoring manuals, converting raw scores to T score metric (mean = 50; SD = 10). A generalized linear mixed model was utilized to examine covariates (i.e., sex, number of visits, and motivation for care) that may have played an important role on the PROMIS outcome.

RESULTS

The original data set consisted of 915 parent-child dyads. After data cleaning, a total of 881 parents (747 females, 134 males; mean age = 42.03 years) and 881 children (467 females and 414 males; mean age = 12.49 years) comprised this study population. The parents were highly educated and presented their child for mainly wellness care. The mean number of days and patient visits from baseline to comparative QoL measures was 38.12 days and 2.74 (SD = 2.61), respectively. After controlling for the effects of motivation for care, patient visits, duration of complaint, sex, and pain rating, significant differences were observed in the probability of experiencing problems (vs. no reported problems) across all QoL domains (Wald = 82.897, df = 4, p < 0.05). Post hoc comparisons demonstrated the children were less likely to report any symptoms of depression (Wald = 6.1474, df = 1, p < 0.05), anxiety (Wald = 20.603, df = 1, p < 0.05), fatigue (Wald = 22.191, df = 1, p < 0.05), and pain interference (Wald = 47.422, df = 1, p < 0.05) after a trial of chiropractic care.

CONCLUSIONS

The QoL of children improved with chiropractic care as measured by PROMIS.

The Use of the Patient Reported Outcomes Measurement Information System and the RAND VSQ9 to Measure the Quality of Life and Visit-Specific Satisfaction of Pregnant Patients Under Chiropractic Care Utilizing the Webster Technique

Objective: To quantify the quality of life (QoL) and visit-specific satisfaction of pregnant women.

Design: A prospective cohort within a practice-based research network (PBRN).

Setting/Locations: Individual chiropractic offices.

Subjects: Pregnant women (age ≥18 years) attending chiropractic care.

Intervention(s): Chiropractic care (i.e., The Webster Technique, spinal adjustments, and adjunctive therapies).

Main outcome measures: The RAND VSQ9 to measure visit-specific satisfaction and the Patient Reported Outcomes Measurement Information System (PROMIS^®)-29 to measure QoL.

Results: A convenience sample of 343 pregnant patients (average age = 30.96 years) comprised their study population. They were highly educated with 75% attaining a 2-year associate's degree or higher. The pregnant patients presented for chiropractic care with a mean week of gestation of 25.67 weeks (median = 28 weeks; range = 0–42 weeks) and parity (i.e., the number of live births) of 0.92 live births (median = 1; range = 0–6). From baseline (i.e., at study entrance with minimum first visit) and comparative (i.e., following a course of chiropractic care), the VSQ9 measurements revealed increasingly high satisfaction on the part of the subjects (i.e., the mean difference of baseline minus comparative measures = −0.7322; p < 0.005). The median number of visits (i.e., visits attended) at baseline and comparative measures was 1.00 (standard deviation [SD] = 22.69) and 3.30 (SD = 22.71), respectively. Across outcomes, QoL improved from baseline to comparative measurement after holding constant for visit number and time lapse, trimester of pregnancy, and care provider type. There was a reduction in mean T scores associated with fatigue (p < 0.05), pain interference (p < 0.05), sleep disturbance (p < 0.05), and an improvement in satisfaction with social roles (p < 0.05). A significant decrease was also found with pain interference (p < 0.05). No evidence was found that anxiety (p = 0.1404) or depression (p = 0.8785) changed.

Conclusion: A PBRN study was successfully implemented among chiropractors to find pregnant patients highly satisfied and their QoL scores improving with care beyond chance.

Patient-centered professional practice models for managing low back pain in older adults: a pilot randomized controlled trial

BACKGROUND

Low back pain is a debilitating condition for older adults, who may seek healthcare from multiple providers. Few studies have evaluated impacts of different healthcare delivery models on back pain outcomes in this population. The purpose of this study was to compare clinical outcomes of older adults receiving back pain treatment under 3 professional practice models that included primary medical care with or without chiropractic care.

METHODS

We conducted a pilot randomized controlled trial with 131 community-dwelling, ambulatory older adults with subacute or chronic low back pain. Participants were randomly allocated to 12 weeks of individualized primary medical care (Medical Care), concurrent medical and chiropractic care (Dual Care), or medical and chiropractic care with enhanced interprofessional collaboration (Shared Care). Primary outcomes were low back pain intensity rated on the numerical rating scale and back-related disability measured with the Roland-Morris Disability Questionnaire. Secondary outcomes included clinical measures, adverse events, and patient satisfaction. Statistical analyses included mixed-effects regression models and general estimating equations.

RESULTS

At 12 weeks, participants in all three treatment groups reported improvements in mean average low back pain intensity [Shared Care: 1.8; 95% confidence interval (CI) 1.0 to 2.6; Dual Care: 3.0; 95% CI 2.3 to 3.8; Medical Care: 2.3; 95% CI 1.5 to 3.2)] and back-related disability (Shared Care: 2.8; 95% CI 1.6 to 4.0; Dual Care: 2.5; 95% CI 1.3 to 3.7; Medical Care: 1.5; 95% CI 0.2 to 2.8). No statistically significant differences were noted between the three groups on the primary measures. Participants in both models that included chiropractic reported significantly better perceived low back pain improvement, overall health and quality of life, and greater satisfaction with healthcare services than patients who received medical care alone.

CONCLUSIONS

Professional practice models that included primary care and chiropractic care led to modest improvements in low back pain intensity and disability for older adults, with chiropractic-inclusive models resulting in better perceived improvement and patient satisfaction over the primary care model alone.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT01312233 , 4 March 2011.

Essential literature for the chiropractic profession: Results and implementation challenges from a survey of international chiropractic faculty

OBJECTIVE

Scientific literature applicable to chiropractic practice proliferates in quantity, quality, and source. Chiropractic is a worldwide profession and varies in scope between states or provinces and from country to country. It is logical to consider that the focus and emphasis of chiropractic education varies between programs as well. This original research study endeavored to determine "essential literature" recommended by chiropractic faculty. The purpose of this article is (1) to share our results and (2) to promote discussion and explore means for future collaboration of chiropractic faculty through a worldwide platform.

METHODS

A 2-phase recruitment occurred initially at the institutional level and subsequently at the faculty level. A Web-based survey used qualitative data collection methods to gather bibliographic citations. Descriptive statistics were calculated for demographics, and citation responses were ranked per number of recommendations, grouped into categories, and tabulated per journal source and publication date.

RESULTS

Forty-one chiropractic programs were contacted, resulting in 30 participating chiropractic programs (16 US and 14 international). Forty-five faculty members completed the entire survey, submitting 126 peer-reviewed publications and 25 additional citations. Readings emphasized clinical management of spine pain, the science of spinal manipulation, effectiveness of manual therapies, teaching of chiropractic techniques, outcomes assessments, and professional issues.

CONCLUSION

A systematic approach to surveying educators in international chiropractic institutions was accomplished. The results of the survey provide a list of essential literature for the chiropractic profession. We recommend establishing a chiropractic faculty registry for improved communication and collaboration.

Integrative Pain Management

Chronic pain is one of the most common conditions seen in the clinic, and it is often one of the most frustrating for both clinicians and patients. This condition stems from common comorbidities, including depression, insomnia, fatigue, and physical deconditioning, which often create barriers to recovery. In addition, chronic pain has had divergent approaches for treatment, including an overemphasis on analgesia and curative treatments while underemphasizing the biopsychosocial needs of those in pain. This article attempts to provide an initial framework for approaching those in pain and initiating patient-centered options to support improvements in pain, function, and self-care.

Interdisciplinary rehabilitation for a patient with incomplete cervical spinal cord injury and multimorbidity: A case report

RATIONALE

This report describes interdisciplinary rehabilitation for a 51-year-old male recovering from incomplete cervical spinal cord injury (SCI) and multiple comorbidities following an automobile accident.

PATIENT CONCERNS

The patient was admitted to a rehabilitation specialty hospital approximately 2 months post SCI and 2 separate surgical fusion procedures (C3-C6).

DIAGNOSES

Clinical presentation at the rehabilitation hospital included moderate to severe motor strength loss in both upper and lower extremities, a percutaneous endoscopic gastronomy tube (PEG), dysphagia, bowel/bladder incontinence, dependence on a mechanical lift and tilting wheelchair due to severe orthostatic hypotension, and pre-existing shoulder pain from bilateral joint degeneration.

INTERVENTIONS

The interdisciplinary team formally coordinated rehabilitative care from multiple disciplines. Internal medicine managed medications, determined PEG removal, monitored co-morbid conditions, and overall progress. Chiropractic care focused on alleviating shoulder and thoracic pain and improving spinal and extremity mobility. Physical therapy addressed upright tolerance, transfer, gait, and strength training. Occupational therapy focused on hand coordination and feeding/dressing activities. Psychology assisted with coping strategies. Nursing ensured medication adherence, nutrient intake, wound prevention, and incontinence management, whereas physiatry addressed abnormal muscle tone.

OUTCOMES

Eleven months post-admission the patient's progress allowed discharge to a long-term care facility. At this time he was without dysphagia or need for a PEG. Orthostatic hypotension and bilateral shoulder pain symptoms were also resolved while bowel/bladder incontinence and upper and lower extremity motor strength loss remained. He was largely independent in transferring from bed to wheelchair and in upper body dressing. Lower body dressing/bathing required maximal assistance. Gait with a 2-wheeled walker was possible up to 150 feet with verbal cues and occasional stabilizing assistance.

LESSONS

Several specialties functioning within an interdisciplinary team fulfilled complementary roles to support rehabilitation for a patient with SCI.

Effective treatment options for musculoskeletal pain in primary care: A systematic overview of current evidence

BACKGROUND & AIMS

Musculoskeletal pain, the most common cause of disability globally, is most frequently managed in primary care. People with musculoskeletal pain in different body regions share similar characteristics, prognosis, and may respond to similar treatments. This overview aims to summarise current best evidence on currently available treatment options for the five most common musculoskeletal pain presentations (back, neck, shoulder, knee and multi-site pain) in primary care.

METHODS

A systematic search was conducted. Initial searches identified clinical guidelines, clinical pathways and systematic reviews. Additional searches found recently published trials and those addressing gaps in the evidence base. Data on study populations, interventions, and outcomes of intervention on pain and function were extracted. Quality of systematic reviews was assessed using AMSTAR, and strength of evidence rated using a modified GRADE approach.

RESULTS

Moderate to strong evidence suggests that exercise therapy and psychosocial interventions are effective for relieving pain and improving function for musculoskeletal pain. NSAIDs and opioids reduce pain in the short-term, but the effect size is modest and the potential for adverse effects need careful consideration. Corticosteroid injections were found to be beneficial for short-term pain relief among patients with knee and shoulder pain. However, current evidence remains equivocal on optimal dose, intensity and frequency, or mode of application for most treatment options.

CONCLUSION

This review presents a comprehensive summary and critical assessment of current evidence for the treatment of pain presentations in primary care. The evidence synthesis of interventions for common musculoskeletal pain presentations shows moderate-strong evidence for exercise therapy and psychosocial interventions, with short-term benefits only from pharmacological treatments. Future research into optimal dose and application of the most promising treatments is needed.

Association of lumbar spine stiffness and flexion-relaxation phenomenon with patient-reported outcomes in adults with chronic low back pain - a single-arm clinical trial investigating the effects of thrust spinal manipulation

Background

Spinal manipulation (SM) is used commonly for treating low back pain (LBP). Spinal stiffness is routinely assessed by clinicians performing SM. Flexion-relaxation ratio (FRR) was shown to distinguish between LBP and healthy populations. The primary objective of this study was to examine the association of these two physiological variables with patient-reported pain intensity and disability in adults with chronic LBP (>12 weeks) receiving SM.

Methods

A single-arm trial provided 12 sessions of side-lying thrust SM in the lumbosacral region over 6 weeks. Inclusion criteria included 21–65 years old, Roland-Morris Disability Questionnaire (RMDQ) score ≥ 6 and numerical pain rating score ≥ 2. Spinal stiffness and FRR were assessed pre-treatment at baseline, after 2 weeks and after 6 weeks of treatment. Lumbar spine global stiffness (GS) were calculated from the force-displacement curves obtained using i) hand palpation, ii) a hand-held device, and iii) an automated indenter device. Lumbar FRR was assessed during trunk flexion-extension using surface electromyography. The primary outcomes were RMDQ and pain intensity measured by visual analog scale (VAS). Mixed-effects regression models were used to analyze the data.

Results

The mean age of the 82 participants was 45 years; 48% were female; and 84% reported LBP >1 year. The mean (standard deviation) baseline pain intensity and RMDQ were 46.1 (18.1) and 9.5 (4.3), respectively. The mean reduction (95% confidence interval) after 6 weeks in pain intensity and RMDQ were 20.1 mm (14.1 to 26.1) and 4.8 (3.7 to 5.8). There was a small change over time in the palpatory GS but not in the hand-held or automated GS, nor in FRR. The addition of each physiologic variable did not affect the model-estimated changes in VAS or RMDQ over time. There was no association seen between physiological variables and LBP intensity. Higher levels of hand-held GS at L3 and automated GS were significantly associated with higher levels of RMDQ (p = 0.02 and 0.03, respectively) and lower levels of flexion and extension FRR were significantly associated with higher levels of RMDQ (p = 0.02 and 0.008, respectively) across the 3 assessment time points.

Conclusions

Improvement in pain and disability observed in study participants with chronic LBP was not associated with the measured GS or FRR.

Trial registration

NCT01670292 on clinicaltrials.gov, August 2, 2012

Integrative Acupuncture and Spinal Manipulative Therapy Versus Either Alone for Low Back Pain: A Randomized Controlled Trial Feasibility Study

OBJECTIVES

The objective of this study was to assess the feasibility of conducting a large-scale randomized controlled trial (RCT) examining whether an integrative care model combining spinal manipulative therapy (SMT) and acupuncture can lead to better outcomes for low back pain (LBP) than either therapy alone.

METHODS

This study was conducted at a complementary and alternative medicine university health center. Participants with acute or chronic LBP were randomized to (1) acupuncture, (2) SMT, or (3) integrative acupuncture and SMT groups. Treatments were provided over 60 days by licensed doctors of chiropractic and acupuncturists. Acupuncture treatments consisted of needling of acupoints combined with electrotherapy, moxibustion, cupping, and Tui Na. SMT used specific contact points on vertebral processes, along with soft tissue therapy and physiotherapy. Primary outcome measures were the Roland-Morris LBP Disability Questionnaire and 0 to 10 Numeric Rating Scale for LBP.

RESULTS

Participants in all 3 groups experienced clinically meaningful improvements in the primary outcome measures; however, no between-group differences in outcomes were apparent.

CONCLUSIONS

This study indicated that it is feasible to conduct an RCT to compare the effectiveness of integrative acupuncture and SMT for LBP to either therapy alone. Future studies should include a larger sample to increase the power for detecting clinically meaningful differences between groups.

Effect of lumbar spinal manipulation on local and remote pressure pain threshold and pinprick sensitivity in asymptomatic individuals: a randomised trial

BACKGROUND

The mechanisms of clinical pain relief associated with spinal manipulative therapy (SMT) are poorly understood. Our objective was to determine whether lumbar high-velocity low-amplitude SMT altered pressure pain threshold (PPT) and pinprick sensitivity (PPS) locally and remotely, how long any change lasted (up to 30 min), and whether changes related to the side of SMT.

METHODS

Thirty-four asymptomatic participants (mean age 22.6 years ±4.0) received a right- or left-sided lumbar SMT. PPT and PPS were measured bilaterally at the calf, lumbar spine, scapula, and forehead before and immediately, 10, 20, and 30 min after intervention. Data were collected between October 2014 and June 2015.

RESULTS

Bilateral calf and lumbar spine PPT increased significantly after 10 - 20 min and was maintained at 30 min (7.2-11.8 % increase). PPS decreased significantly in all locations at various times (9.8 - 22.5 % decrease). At the calf and lumbar spine, PPT increased slightly more ipsilateral to the SMT than contralateral.

CONCLUSIONS

Lumbar SMT reduced deep pressure sensitivity locally and in the lower limbs for at least 30 min, whereas sensitivity to pinprick was reduced systemically. These findings suggest that SMT specifically inhibits deep pressure sensitivity distally. These findings are novel compared to other lumbar SMT studies, and may reflect a local spinal or complex supraspinal analgesic mechanism.

TRIAL REGISTRATION

Registered with the Australian New Zealand Clinical Trials Registry (ACTRN12614000682640).

The effect of chiropractic treatment on the reaction and response times of special operation forces military personnel: study protocol for a randomized controlled trial

Background

Chiropractic care is commonly used to treat musculoskeletal conditions and has been endorsed by clinical practice guidelines as being evidence-based and cost-effective for the treatment of patients with low back pain. Gaps in the literature exist regarding the physiological outcomes of chiropractic treatment. Previous pilot work has indicated the possibility of improvements in response time following the application of chiropractic treatment. However, it is unknown whether or not chiropractic treatment is able to improve reaction and response times in specific populations of interest. One such population is the U.S. military special operation forces’ (SOF) personnel.

Methods

This study is a randomized controlled trial of 120 asymptomatic volunteer SOF personnel. All participants are examined by a study doctor of chiropractic (DC) for eligibility prior to randomization. The participants are randomly allocated to either a treatment group receiving four treatments of chiropractic manipulative therapy (CMT) over 2 weeks or to a wait-list control group. The wait-list group does not receive any treatment but has assessments at the same time interval as the treatment group. The outcome measures are simple reaction times for dominant hand and dominant foot, choice reaction time with prompts calling for either hand or either foot, response time using Fitts’ law tasks for small movements involving eye-hand coordination, and brief whole body movements using the t-wall, a commercially available product. At the first visit, all five tests are completed so that participants can familiarize themselves with the equipment and protocol. Assessments at the second and the final visits are used for data analysis.

Discussion

SOF personnel are highly motivated and extremely physically fit individuals whose occupation requires reaction times that are as quick as possible during the course of their assigned duties. A goal of CMT is to maximize the functionality and integration of the neuromusculoskeletal systems. Therefore, chiropractic treatment may be able to optimize the capacity of the numerous components of those systems, resulting in improved reaction time. The objective of this study is to test the hypothesis that CMT improves reaction and response times in asymptomatic SOF personnel.

Trial registration

ClinicalTrials.gov, NCT02168153. Registered on 12 June 2014.

Similar Effects of Thrust and Nonthrust Spinal Manipulation Found in Adults With Subacute and Chronic Low Back Pain: A Controlled Trial With Adaptive Allocation

STUDY DESIGN

A three-arm controlled trial with adaptive allocation.

OBJECTIVES

The aim of this study was to compare short-term effects of a side-lying, thrust spinal manipulation (SM) procedure and a nonthrust, flexion-distraction SM procedure in adults with subacute or chronic low back pain (LBP) over 2 weeks.

SUMMARY OF BACKGROUND DATA

SM has been recommended in recently published clinical guidelines for LBP management. Previous studies suggest that thrust and nonthrust SM procedures, though distinctly different in joint loading characteristics, have similar effects on patients with LBP.

METHODS

Participants were eligible if they were 21 to 54 years old, had LBP for at least 4 weeks, scored 6 or above on the Roland-Morris disability questionnaire, and met the diagnostic classification of 1, 2, or 3 according to the Quebec Task Force Classification for Spinal Disorders. Participants were allocated in a 3:3:2 ratio to four sessions of thrust or nonthrust SM procedures directed at the lower lumbar and pelvic regions, or to a 2-week wait list control. The primary outcome was LBP-related disability using Roland-Morris Disability Questionnaire and the secondary outcomes were LBP intensity using visual analog scale, Fear-Avoidance Beliefs Questionnaire, and the 36-Item Short Form Health Survey. The study was conducted at the Palmer Center for Chiropractic Research with care provided by experienced doctors of chiropractic. Clinicians and patients were not blinded to treatment group.

RESULTS

Of 192 participants enrolled, the mean age was 40 years and 54% were male. Improvement in disability, LBP intensity, Fear-Avoidance Beliefs Questionnaire-work subscale, and 36-Item Short Form Health Survey-physical health summary measure for the two SM groups were significantly greater than the control group. No difference in any outcomes was observed between the two SM groups.

CONCLUSION

Thrust and nonthrust SM procedures with distinctly different joint loading characteristics demonstrated similar effects in short-term LBP improvement and both were superior to a wait list control.

LEVEL OF EVIDENCE

2.

Assessment of chiropractic treatment for active duty, U.S. military personnel with low back pain: study protocol for a randomized controlled trial

BACKGROUND

Low back pain is highly prevalent and one of the most common causes of disability in U.S. armed forces personnel. Currently, no single therapeutic method has been established as a gold standard treatment for this increasingly prevalent condition. One commonly used treatment, which has demonstrated consistent positive outcomes in terms of pain and function within a civilian population is spinal manipulative therapy provided by doctors of chiropractic. Chiropractic care, delivered within a multidisciplinary framework in military healthcare settings, has the potential to help improve clinical outcomes for military personnel with low back pain. However, its effectiveness in a military setting has not been well established. The primary objective of this study is to evaluate changes in pain and disability in active duty service members with low back pain who are allocated to receive usual medical care plus chiropractic care versus treatment with usual medical care alone.

METHODS/DESIGN

This pragmatic comparative effectiveness trial will enroll 750 active duty service members with low back pain at three military treatment facilities within the United States (250 from each site) who will be allocated to receive usual medical care plus chiropractic care or usual medical care alone for 6 weeks. Primary outcomes will include the numerical rating scale for pain intensity and the Roland-Morris Disability Questionnaire at week 6. Patient reported outcomes of pain, disability, bothersomeness, and back pain function will be collected at 2, 4, 6, and 12 weeks from allocation.

DISCUSSION

Because low back pain is one of the leading causes of disability among U.S. military personnel, it is important to find pragmatic and conservative treatments that will treat low back pain and preserve low back function so that military readiness is maintained. Thus, it is important to evaluate the effects of the addition of chiropractic care to usual medical care on low back pain and disability.

TRIAL REGISTRATION

The trial discussed in this article was registered in ClinicalTrials.gov with the NCT01692275 Date of registration: 6 September 2012.

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.

Safety of thrust joint manipulation in the thoracic spine: a systematic review

BACKGROUND

There appears to be very little in the research literature on the safety of thrust joint manipulation (TJM) when applied to the thoracic spine.

PURPOSE

To retrospectively analyze all available documented case reports in the literature describing patients who had experienced severe adverse events (AE) after receiving TJM to their thoracic spine.

DATA SOURCES

Case reports published in peer reviewed journals were searched in Medline (using Ovid Technologies, Inc.), Science Direct, Web of Science, PEDro (Physiotherapy Evidence Database), Index of Chiropractic literature, AMED (Allied and Alternative Medicine Database), PubMed and the Cumulative Index to Nursing and Allied Health (CINHAL) from January 1950 to February 2015.

STUDY SELECTION

Case reports were included if they: (1) were peer-reviewed; (2) were published between 1950 and 2015; (3) provided case reports or case series; and (4) had TJM as an intervention. Articles were excluded if: (1) the AE occurred without TJM (e.g. spontaneous); (2) the article was a systematic or literature review; or (3) it was written in a language other than English or Spanish.

DATA EXTRACTION

Data extracted from each case report included: gender; age; who performed the TJM and why; presence of contraindications; the number of manipulation interventions performed; initial symptoms experienced after the TJM; as well as type of severe AE that resulted.

RESULTS

Ten cases, reported in 7 case reports, were reviewed. Cases involved females (8) more than males (2), with mean age being 43.5 years (SD=18.73, Range = 17 -71). The most frequent AE reported was injury (mechanical or vascular) to the spinal cord (7/10), with pneumothorax and hematothorax (2/10) and CSF leak secondary to dural sleeve injury (1/10).

LIMITATIONS

There were only a small number of case reports published in the literature and there may have been discrepancies between what was reported and what actually occurred, since physicians dealing with the effects of the AE, rather than the clinician performing the TJM, published the cases.

CONCLUSIONS

Serious AE do occur in the thoracic spine, most commonly, trauma to the spinal cord, followed by pneumothorax. This suggests that excessive peak forces may have been applied to thoracic spine, and it should serve as a cautionary note for clinicians to decrease these peak forces.

Prediction of pain outcomes in a randomized controlled trial of dose-response of spinal manipulation for the care of chronic low back pain

Background

No previous studies have created and validated prediction models for outcomes in patients receiving spinal manipulation for care of chronic low back pain (cLBP). We therefore conducted a secondary analysis alongside a dose-response, randomized controlled trial of spinal manipulation.

Methods

We investigated dose, pain and disability, sociodemographics, general health, psychosocial measures, and objective exam findings as potential predictors of pain outcomes utilizing 400 participants from a randomized controlled trial. Participants received 18 sessions of treatment over 6-weeks and were followed for a year. Spinal manipulation was performed by a chiropractor at 0, 6, 12, or 18 visits (dose), with a light-massage control at all remaining visits. Pain intensity was evaluated with the modified von Korff pain scale (0–100). Predictor variables evaluated came from several domains: condition-specific pain and disability, sociodemographics, general health status, psychosocial, and objective physical measures. Three-quarters of cases (training-set) were used to develop 4 longitudinal models with forward selection to predict individual “responders” (≥50 % improvement from baseline) and future pain intensity using either pretreatment characteristics or post-treatment variables collected shortly after completion of care. The internal validity of the predictor models were then evaluated on the remaining 25 % of cases (test-set) using area under the receiver operating curve (AUC), R², and root mean squared error (RMSE).

Results

The pretreatment responder model performed no better than chance in identifying participants who became responders (AUC = 0.479). Similarly, the pretreatment pain intensity model predicted future pain intensity poorly with low proportion of variance explained (R² = .065). The post-treatment predictor models performed better with AUC = 0.665 for the responder model and R² = 0.261 for the future pain model. Post-treatment pain alone actually predicted future pain better than the full post-treatment predictor model (R² = 0.350). The prediction errors (RMSE) were large (19.4 and 17.5 for the pre- and post-treatment predictor models, respectively).

Conclusions

Internal validation of prediction models showed that participant characteristics preceding the start of care were poor predictors of at least 50 % improvement and the individual’s future pain intensity. Pain collected shortly after completion of 6 weeks of study intervention predicted future pain the best.

Effects of spinal manipulation on sensorimotor function in low back pain patients--A randomised controlled trial

BACKGROUND

Low back pain (LBP) is a major health problem in industrialized societies. Spinal manipulation (SM) is often used for treating LBP, though the therapeutic mechanisms remain elusive. Research suggests that sensorimotor changes may be involved in LBP. It is hypothesized that SM may generate its beneficial effects by affecting sensorimotor functions.

OBJECTIVES

To compare changes in sensorimotor function, as measured by postural sway and response to sudden load, in LBP patients following the delivery of high-velocity low amplitude (HVLA)-SM or low-velocity variable amplitude (LVVA)-SM versus a sham control intervention.

DESIGN

A three-arm (1:1:1 ratio) randomized controlled trial.

METHODS

A total of 221 participants who were between 21 and 65 years, having LBP intensity (numerical rating scale) ≥4 at either phone screen or the first baseline visit and ≥2 at phone screen and both baseline visits, and Quebec Task Force diagnostic classifications of 1, 2, 3 or 7 were enrolled to receive four SM treatments over two weeks. Study outcomes were measured at the first and fifth visits with the examiners blinded from participant group assignment.

RESULTS

The LVVA-SM group demonstrated a significant increase in medial-to-lateral postural excursion on the soft surface at the first visit when compared to the control group. No other significant between-group differences were found for the two sensorimotor tests, whether during the first visit or over two weeks.

CONCLUSIONS

It appears that short-term SM does not affect the sensorimotor functions as measured by postural sway and response to sudden load in this study.

The Chiropractic Hospital-Based Interventions Research Outcomes Study: Consistency of Outcomes Between Doctors of Chiropractic Treating Patients With Acute Lower Back Pain

OBJECTIVE

The aim of this study was to determine if effectiveness differs between community-based doctors of chiropractic administering standardized evidence-based care that includes high-velocity low-amplitude spinal manipulative therapy (SMT) for acute low back pain (LBP).

METHODS

A secondary analysis of randomized controlled trial and observational pilot study data was performed with nonrandom allocation to 4 DCs. Patients included those with Quebec Task Force categories less than or equal to 2 and acute LBP of 2 to 4 weeks' duration. The intervention provided was clinical practice guidelines-based care including high-velocity low-amplitude SMT. Primary outcomes included changes from baseline in modified Roland Disability Questionnaire (RDQ) at 24 weeks. Comparisons of simple main effects at 24 weeks and of marginal main effects in repeated-measures analyses were performed.

RESULTS

Between groups, adjusted point-specific differences in RDQ change were minimally clinically important but not statistically significant at 24 weeks (largest pairwise difference, -3.1; 95% confidence interval, -6.3 to 0.1; overall P = .10). However, in optimal analyses that considered the repeated nature of the measurements for each outcome, significant differences in marginal mean RDQ changes were found between groups (largest pairwise difference, -3.8; 95% confidence interval, -4.9 to 2.6; overall P = .03).

CONCLUSIONS

Overall, DCs differed modestly in their effectiveness in improving LBP-specific disability. The point estimates mirrored typically reported effect sizes from recent systematic reviews of SMT; however, confidence limits did not exclude clinically negligible effects.

The use of PROMIS and the RAND VSQ9 in chiropractic patients receiving care with the Webster Technique

INTRODUCTION

Our ongoing efforts to demonstrate effectiveness of care examined the quality of life (QoL) and patient satisfaction of chiropractic patients presenting for care in a PBRN.

METHODS

In addition to socio-demographic and clinical care information, we examined visit-specific satisfaction and QoL using the RAND VSQ and PROMIS-29, respectively.

RESULTS

Our study population was comprised of 126 subjects (average age = 39.68; 97 females). The majority of respondents presented with musculoskeletal complaints with an average mean duration of 7.188 years. The mean PROMIS-25 mean T Scores were: depression (47.80); pain interference (53.49); fatigue (51.02); physical function (49.02); satisfaction with social role (52.10); anxiety (50.14); and sleep disturbance (49.88). The VSQ9 mean score was 93.4% indicating high satisfaction.

CONCLUSIONS

Adults attending care in a chiropractic PBRN were able to successfully complete the PROMIS29 and VSQ9 instruments. Future longitudinal studies should quantify the minimal clinically important difference in mean T score changes.

Effect of spinal manipulation thrust magnitude on trunk mechanical activation thresholds of lateral thalamic neurons

OBJECTIVES

High-velocity low-amplitude spinal manipulation (HVLA-SM), as performed by doctors who use manual therapy (eg, doctors of chiropractic and osteopathy), results in mechanical hypoalgesia in clinical settings. This hypoalgesic effect has previously been attributed to alterations in peripheral and/or central pain processing. The objective of this study was to determine whether thrust magnitude of a simulated HVLA-SM alters mechanical trunk response thresholds in wide dynamic range (WDR) and/or nociceptive specific (NS) lateral thalamic neurons.

METHODS

Extracellular recordings were carried out in the thalamus of 15 anesthetized Wistar rats. Lateral thalamic neurons having receptive fields, which included the lumbar dorsal-lateral trunk, were characterized as either WDR (n=22) or NS (n=25). Response thresholds to electronic von Frey (rigid tip) mechanical trunk stimuli were determined in 3 directions (dorsal-ventral, 45° caudalward, and 45° cranialward) before and immediately after the dorsal-ventral delivery of a 100-millisecond HVLA-SM at 3 thrust magnitudes (control, 55%, 85% body weight).

RESULTS

There was a significant difference in mechanical threshold between 85% body weight manipulation and control thrust magnitudes in the dorsal-ventral direction in NS neurons (P=.01). No changes were found in WDR neurons at either HVLA-SM thrust magnitude.

CONCLUSIONS

This study is the first to investigate the effect of HVLA-SM thrust magnitude on WDR and NS lateral thalamic mechanical response threshold. Our data suggest that, at the single lateral thalamic neuron level, there may be a minimal spinal manipulative thrust magnitude required to elicit an increase in trunk mechanical response thresholds.

The use of validated outcome measures in the chiropractic care of pregnant patients: A systematic review of the literature

BACKGROUND

Healthcare systems recognize the need to incorporate patient-reported outcomes as part of their clinical and research measures. We performed this review on the use of validated outcome measures in the chiropractic care of pregnant patients.

METHODS

Pubmed, CINAHL, Medline, Index to Chiropractic Literature and MANTIS were searched for (1) primary investigation reports (i.e., case reports, case series, case control, randomized controlled trials and survey or surveillance studies) published in English; (2) involving the care of pregnant patient(s) and (3) utilizing a valid outcome measure.

RESULTS

Our review found 8 articles using the Patient's Global Impression of Change, the NRS, the Oswestry, Bournemouth, Fear Avoidance Belief and Quebec Disability questionnaires, PROMIS-29 and the Measure Yourself Medical Outcome Profile.

CONCLUSION

Despite their heterogeneity and inconsistency of use in the studies reviewed, our findings demonstrate some measure of effectiveness in the chiropractic care of pregnant patients.

Chiropractor interaction and treatment equivalence in a pilot randomized controlled trial: an observational analysis of clinical encounter video-recordings

Background

Chiropractic care is a complex health intervention composed of both treatment effects and non-specific, or placebo, effects. While doctor-patient interactions are a component of the non-specific effects of chiropractic, these effects are not evaluated in most clinical trials. This study aimed to: 1) develop an instrument to assess practitioner-patient interactions; 2) determine the equivalence of a chiropractor’s verbal interactions and treatment delivery for participants allocated to active or sham chiropractic groups; and 3) describe the perceptions of a treatment-masked evaluator and study participants regarding treatment group assignment.

Methods

We conducted an observational analysis of digital video-recordings derived from study visits conducted during a pilot randomized trial of conservative therapies for temporomandibular pain. A theory-based, iterative process developed the 13-item Chiropractor Interaction and Treatment Equivalence Instrument. A trained evaluator masked to treatment assignment coded video-recordings of clinical encounters between one chiropractor and multiple visits of 26 participants allocated to active or sham chiropractic treatment groups. Non-parametric statistics were calculated.

Results

The trial ran from January 2010 to October 2011. We analyzed 111 complete video-recordings (54 active, 57 sham). Chiropractor interactions differed between the treatment groups in 7 categories. Active participants received more interactions with clinical information (8 vs. 4) or explanations (3.5 vs. 1) than sham participants within the therapeutic domain. Active participants received more directions (63 vs. 58) and adjusting instrument thrusts (41.5 vs. 23) in the procedural domain and more optimistic (2.5 vs. 0) or neutral (7.5 vs. 5) outcome statements in the treatment effectiveness domain. Active participants recorded longer visit durations (13.5 vs. 10 minutes). The evaluator correctly identified 61% of active care video-recordings as active treatments but categorized only 31% of the sham treatments correctly. Following the first treatment, 82% of active and 11% of sham participants correctly identified their treatment group. At 2-months, 93% of active and 42% of sham participants correctly identified their group assignment.

Conclusions

Our findings show the feasibility of evaluating doctor-patient interactions in chiropractic clinical trials using video-recordings and standardized instrumentation. Clinical trial design and clinician training protocols should improve and assess the equivalence of doctor-patient interactions between treatment groups.

Trial registration

This trial was registered in ClinicalTrials.gov as NCT01021306 on 24 November 2009.

Assessing the change in attitudes, knowledge, and perspectives of medical students towards chiropractic after an educational intervention

Objective : We assessed the change in attitudes, knowledge, and perspectives of medical students towards chiropractic after a 1-hour educational intervention. Methods : A mixed-methods approach was used with a 52-item cross-sectional paper survey and 1 focus group of third-year medical students. The views of these medical students towards chiropractic were assessed previously in their second-year of medical school. ANOVA and the Wilcoxon rank-sum test were used to assess between-group differences between the medical students' views before and after the educational intervention. The constant comparative method for analyzing qualitative data was used to identify emergent themes from the focus group transcript. Results : Of 112 third-year medical students, 58 completed the survey (51.7% response rate). The focus group consisted of 6 medical students. Self-reported understanding of chiropractic and number of attitude-positive responses were significantly higher in the group after the educational session. The average number of correct responses assessing knowledge on chiropractic also was significantly higher. Focus group themes were that medical students wanted exposure to chiropractic in clinical settings, had negative attitudes towards chiropractic formed from hidden curriculum, had concerns regarding evidence and safety of chiropractic, and thought that timing of the session on chiropractic was too late in the curriculum. Conclusions : The attitudes and knowledge of medical students towards chiropractic improved immediately after a 1-hour educational intervention. Formally educating medical students on chiropractic may help minimize hidden curriculum issues regarding chiropractic, as identified by the medical students, and facilitate collaboration between medical and chiropractic providers.

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.

Study protocol for patient response to spinal manipulation - a prospective observational clinical trial on physiological and patient-centered outcomes in patients with chronic low back pain

Background

Low back pain (LBP) is a major health issue due to its high prevalence rate and socioeconomic cost. While spinal manipulation (SM) is recommended for LBP treatment by recently published clinical guidelines, the underlying therapeutic mechanisms remain unclear. Spinal stiffness is routinely examined and used in clinical decisions for SM delivery. It has also been explored as a predictor for clinical improvement. Flexion-relaxation phenomenon has been demonstrated to distinguish between LBP and healthy populations. The primary objective of the current study is to collect preliminary estimates of variability and effect size for the associations of these two physiological measures with patient-centered outcomes in chronic LBP patients. Additionally biomechanical characteristics of SM delivery are collected with the intention to explore the potential dose–response relationship between SM and LBP improvement.

Methods/Design

This is a prospective, observational study applying side-lying, high velocity, low amplitude SM as treatment for patients with LBP over a course of 6 weeks. Approximately 80 participants will be enrolled if they present with chronic LBP of 1, 2 or 3 in Quebec Task Force Classification for spinal disorders, a Roland-Morris Disability Questionnaire (RMDQ) score ≥ 6, and persistent LBP ≥ 2 with a maximum ≥ 4 using numerical rating scale. Patient-centered outcomes include LBP using visual analog scale, RMDQ, and PROMIS-29. Lumbar spine stiffness is assessed using palpation, a hand-held instrumented device, and an automated device. Flexion-relaxation is assessed using surface electromyography at the third level of the lumbar spine. Biomechanical characteristics of SM are assessed using a self-reported, itemized description system, as well as advanced kinetic measures that will be applied to estimate forces and moments at the lumbar segment level targeted by SM.

Discussion

Beside alterations in material properties of the passive components of the spine, increased neuromuscular activity may also contribute to a stiffened spine. Examining changes in both spinal stiffness and flexion-relaxation along the course of the treatment provides an opportunity to understand if the therapeutic effect of SM is associated with its action on active and/or passive components of the spine.

Trial registration

NCT01670292 on clinicaltrials.gov.

Role of rehabilitation medicine and physical agents in the treatment of cancer-associated pain

PURPOSE

To provide an overview of rehabilitation medicine- and physical modality-based approaches to cancer pain management, and to highlight the fact that these approaches are generally used in conjunction and that a majority are focused on minimizing pain during periods of mobility and the performance of activities of daily living.

METHODS

We performed a nonsystematic literature review and provide a description of the current standard of care.

RESULTS

Rehabilitative and physical modalities used to manage pain can be grouped into four categories: those that modulate nociception, stabilize or unload painful structures, influence physiological processes that indirectly influence nociception, or alleviate pain arising from the overloading of muscles and connective tissues that often occurs after surgery or with sarcopenia in late-stage cancer. Most modalities have been pragmatically refined over the years, and many have an evidence base, although few have been explicitly validated in the oncologic setting. With few exceptions, they are patient controlled and free of adverse effects.

CONCLUSION

Physical modalities and rehabilitation medicine offer a range of pain management approaches that may serve as beneficial adjuncts to the conventional systemic and interventional analgesic strategies used to control cancer-related pain. These approaches may be particularly beneficial to patients with movement-associated pain and those who are ambivalent regarding pharmacoanalgesia.

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.

The within-session change in low back pain intensity following spinal manipulative therapy is related to differences in diffusion of water in the intervertebral discs of the upper lumbar spine and L5-S1

STUDY DESIGN

Single-group, prospective, repeated-measures design with responder analysis.

OBJECTIVE

To determine differences in the changes in diffusion of water within the lumbar intervertebral discs between participants with low back pain who reported a within-session reduction in pain intensity following a single treatment of spinal manipulative therapy and those who did not.

BACKGROUND

There is a paucity of research that describes the physiologic events associated with analgesia following intervention for low back pain. Postintervention increases in the diffusion of water within various soft tissues of the spine may be one of many potential mechanisms linked to pain reduction.

METHODS

Nineteen adults between 20 and 45 years of age participated in this study. All participants reported low back pain of at least 2 on an 11-point (0-10) verbally administered numeric pain rating scale at the time of enrollment. Participants underwent T2- and diffusion-weighted lumbar magnetic resonance imaging scans immediately before and after receiving a single treatment of spinal manipulative therapy. Individuals who reported a decrease in current pain intensity of more than 2 following treatment were classified as "within-session responders," and the remainder were classified as "not-within-session responders." The apparent diffusion coefficient (ADC), representing the diffusion of water in the nucleus pulposus, was calculated from ADC maps derived from the midsagittal diffusion-weighted images.

RESULTS

Two-way, repeated-measures analyses of variance indicated significant group-by-time interactions. Participants in the within-session-responder group (n = 12) had a postintervention increase in ADC at L1-2 (P = .001), L2-3 (P = .002), and L5-S1 (P = .01) compared to those in the not-within-session-responder group (n = 7). Large effect sizes in ADC between responder groups were observed at L1-2 (d = 1.74), L2-3 (d = 1.83), and L5-S1 (d = 1.49). No significant group-by-time interactions were observed at the L3-4 and L4-5 levels.

CONCLUSION

Changes in the diffusion of water within the lumbar intervertebral discs at the L1-2, L2-3, and L5-S1 levels appear to be related to differences in within-session pain reports following a single treatment of spinal manipulative therapy.

Effects of thrust amplitude and duration of high-velocity, low-amplitude spinal manipulation on lumbar muscle spindle responses to vertebral position and movement

OBJECTIVE

Mechanical characteristics of high-velocity, low-amplitude spinal manipulations (HVLA-SMs) can vary. Sustained changes in peripheral neuronal signaling due to altered load transmission to a sensory receptor's local mechanical environment are often considered a mechanism contributing to the therapeutic effects of spinal manipulation. The purpose of this study was to determine whether variation in an HVLA-SM's thrust amplitude and duration alters the neural responsiveness of lumbar muscle spindles to either vertebral movement or position.

METHODS

Anesthetized cats (n = 112) received L6 HVLA-SMs delivered to the spinous process. Cats were divided into 6 cohorts depending upon the peak thrust force (25%, 55%, 85% body weight) or thrust displacement (1, 2, 3 mm) they received. Cats in each cohort received 8 thrust durations (0-250 milliseconds). Afferent discharge from 112 spindles was recorded in response to ramp and hold vertebral movement before and after the manipulation. Changes in mean instantaneous frequency (∆MIF) during the baseline period preceding the ramps (∆MIFresting), during ramp movement (∆MIFmovement), and with the vertebra held in the new position (∆MIFposition) were compared.

RESULTS

Thrust duration had a small but statistically significant effect on ∆MIFresting at all 6 thrust amplitudes compared with control (0-millisecond thrust duration). The lowest amplitude thrust displacement (1 mm) increased ∆MIFresting at all thrust durations. For all the other thrust displacements and forces, the direction of change in ∆MIFresting was not consistent, and the pattern of change was not systematically related to thrust duration. Regardless of thrust force, displacement, or duration, ∆MIFmovement and ∆MIFposition were not significantly different from control.

CONCLUSION

Relatively low-amplitude thrust displacements applied during an HVLA-SM produced sustained increases in the resting discharge of paraspinal muscle spindles regardless of the duration over which the thrust was applied. However, regardless of the HVLA-SM's thrust amplitude or duration, the responsiveness of paraspinal muscle spindles to vertebral movement and to a new vertebral position was not affected.

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.