Effect of chiropractic manipulative therapy on reaction time in special operations forces military personnel: a randomized controlled trial.

BACKGROUND: Chiropractic manipulative therapy (CMT) has been shown to improve reaction time in some clinical studies. Slight changes in reaction time can be critical for military personnel, such as special operation forces (SOF). This trial was conducted to test whether CMT could lead to improved reaction and response time in combat-ready SOF-qualified personnel reporting little or no pain. METHODS: This prospective, randomized controlled trial was conducted at Blanchfield Army Community Hospital, Fort Campbell, KY, USA. Active-duty US military participants over the age of 19 years carrying an SOF designation were eligible. Participants were randomly allocated to CMT or wait-list control. One group received four CMT treatments while the other received no treatment within the 2-week trial period. Assessment included simple hand/foot reaction time, choice reaction time, and Fitts' Law and whole-body response time. On visits 1 and 5, the same five assessments were conducted immediately pre- and post-treatment for the CMT group and before and after a 10-min wait period for the wait-list group. Primary outcomes included between-group differences for the pre-CMT/wait-list period at visit 1 and visit 5 for each test. Secondary outcomes included between-group differences in immediate pre- and post-(within visit) changes. Analysis of covariance was used for all data analysis. RESULTS: One hundred and seventy-five SOF-qualified personnel were screened for eligibility; 120 participants were enrolled, with 60 randomly allocated to each group. Due to technical problems resulting in inconsistent data collection, data from 77 participants were analyzed for simple hand/foot reaction time. The mean ± standard deviation (SD) age was 33.0 ± 5.6 years and all participants were male. No between-group statistically significant differences were found for any of the five biomechanical tests, except immediate pre- and post-changes in favor of the CMT group in whole-body response time at both assessment visits. There were four adverse events, none related to trial participation. CONCLUSIONS: A single session of CMT was shown to have an immediate effect of reducing the time required for asymptomatic SOF qualified personnel to complete a complex whole-body motor response task. However, sustained reduction in reaction or response time from five tests compared with a wait-list control group was not observed following three sessions of CMT. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02168153 . Registered on 12 June 2014.

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.

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.

Novel Electromyographic Protocols Using Axial Rotation and Cervical Flexion-Relaxation for the Assessment of Subjects With Neck Pain: A Feasibility Study.

OBJECTIVE: The purpose of this study is to examine the feasibility of novel variations to the way cervical flexion-relaxation phenomenon (FRP) studies are conducted and the feasibility of using cervical axial rotation as an alternative objective measure of cervical pain/dysfunction. METHODS: Electromyographic data were collected from cervical paraspinal muscles of 5 participants with neck pain and 5 asymptomatic controls. Cervical FRP was conducted as reported in the literature with the participants seated, except that they started with the head fully flexed instead of being erect. Data were also collected with participants laying prone, starting with their head hanging over the edge of the table. Additional data were collected from cervical paraspinal and sternocleidomastoid (SCM) muscles while the seated participants rotated their head fully to the right and left. Ratios were obtained for each type of test by dividing the electromyographic amplitude when muscles were most active by that when they were relaxed or in contralateral rotation. RESULTS: In each case, the ratio was higher for the controls than for those with neck pain, suggesting that any of the 4 methods could be used to distinguish between 2 groups. The ratios were most pronounced from SCMs during axial rotation. There appeared to be a negative relationship between pain level and the ratios obtained from each method. CONCLUSION: The findings from this small study are encouraging for all methods used, with axial rotation using SCMs appearing to be the most promising. These results indicate that larger, powered studies are warranted.

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.

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.

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.

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.

A pilot study of a chiropractic intervention for management of chronic myofascial temporomandibular disorder.

BACKGROUND: Temporomandibular pain has multiple etiologies and a range of therapeutic options. In this pilot study, the authors assessed the feasibility of conducting a larger trial to evaluate chiropractic treatment of temporomandibular disorders (TMDs). METHODS: The authors assigned 80 participants randomly into one of the following four groups, all of which included a comprehensive self-care program: reversible interocclusal splint therapy (RIST), Activator Method Chiropractic Technique (AMCT) (Activator Methods International, Phoenix), sham AMCT and self-care only. They made assessments at baseline and at month 2 and month 6, including use of the Research Diagnostic Criteria for Temporomandibular Disorders. RESULTS: The authors screened 721 potential participants and enrolled 80 people; 52 participants completed the six-month assessment. The adjusted mean change in current pain over six months, as assessed on the 11-point numerical rating scale, was 2.0 (95 percent confidence interval, 1.1-3.0) for RIST, 1.7 (0.9-2.5) for self-care only, 1.5 (0.7-2.4) for AMCT and 1.6 (0.7-2.5) for sham AMCT. The authors also assessed bothersomeness and functionality. CONCLUSIONS: The authors found the study design and methodology to be manageable. They gained substantial knowledge to aid in conducting a larger study. AMCT, RIST and self-care should be evaluated in a future comparative effectiveness study. PRACTICAL IMPLICATIONS: This pilot study was a necessary step to prepare for a larger study that will provide clinicians with information that should be helpful when discussing treatment options for patients with TMD.

Force-time profile differences in the delivery of simulated toggle-recoil spinal manipulation by students, instructors, and field doctors of chiropractic.

OBJECTIVES: The objectives of this study were to examine the force-time profiles of toggle recoil using an instrumented simulator to objectively measure and evaluate students' skill to determine if they become quicker and use less force during the course of their training and to compare them to course instructors and to field doctors of chiropractic (DCs) who use this specific technique in their practices. METHODS: A load cell was placed within a toggle recoil training device. The preload, speed, and magnitude of the toggle recoil thrusts were measured from 60 students, 2 instructors, and 77 DCs (ie, who use the toggle recoil technique in their regular practice). Student data were collected 3 times during their toggle course (after first exposure, at midterm, and at course end.) RESULTS: Thrusts showed a dual-peak force-time profile not previously described in other forms of spinal manipulation. There was a wide range of values for each quantity measured within and between all 3 subject groups. The median peak load for students decreased over the course of their class, but they became slower. Field doctors were faster than students or instructors and delivered higher peak loads. CONCLUSION: Toggle recoil thrusts into a dropping mechanism varied based upon subject and amount of time practicing the task. As students progressed through the class, speed reduced as they increased control to lower peak loads. In the group studies, field DCs applied higher forces and were faster than both students and instructors. There appears to be a unique 2-peak feature of the force-time plot that is unique to toggle recoil manipulation with a drop mechanism.

Effect of spinal manipulation on sensorimotor functions in back pain patients: study protocol for a randomised controlled trial.

BACKGROUND: Low back pain (LBP) is a recognized public health problem, impacting up to 80% of US adults at some point in their lives. Patients with LBP are utilizing integrative health care such as spinal manipulation (SM). SM is the therapeutic application of a load to specific body tissues or structures and can be divided into two broad categories: SM with a high-velocity low-amplitude load, or an impulse "thrust", (HVLA-SM) and SM with a low-velocity variable-amplitude load (LVVA-SM). There is evidence that sensorimotor function in people with LBP is altered. This study evaluates the sensorimotor function in the lumbopelvic region, as measured by postural sway, response to sudden load and repositioning accuracy, following SM to the lumbar and pelvic region when compared to a sham treatment. METHODS/DESIGN: A total of 219 participants with acute, subacute or chronic low back pain are being recruited from the Quad Cities area located in Iowa and Illinois. They are allocated through a minimization algorithm in a 1:1:1 ratio to receive either 13 HVLA-SM treatments over 6 weeks, 13 LVVA-SM treatments over 6 weeks or 2 weeks of a sham treatment followed by 4 weeks of full spine "doctor's choice" SM. Sensorimotor function tests are performed before and immediately after treatment at baseline, week 2 and week 6. Self-report outcome assessments are also collected. The primary aims of this study are to 1) determine immediate pre to post changes in sensorimotor function as measured by postural sway following delivery of a single HVLA-SM or LVVA-SM treatment when compared to a sham treatment and 2) to determine changes from baseline to 2 weeks (4 treatments) of HVLA-SM or LVVA-SM compared to a sham treatment. Secondary aims include changes in response to sudden loads and lumbar repositioning accuracy at these endpoints, estimating sensorimotor function in the SM groups after 6 weeks of treatment, and exploring if changes in sensorimotor function are associated with changes in self-report outcome assessments. DISCUSSION: This study may provide clues to the sensorimotor mechanisms that explain observed functional deficits associated with LBP, as well as the mechanism of action of SM. TRIAL REGISTRATION: This trial is registered in ClinicalTrials.gov, with the ID number of NCT00830596, registered on January 27, 2009. The first participant was allocated on 30 January 2009 and the final participant was allocated on 17 March 2011.

Introducing the external link model for studying spine fixation and misalignment: current procedures, costs, and failure rates.

OBJECTIVE: This is the last article in a series of 3 articles introducing a new animal model, the external link model (ELM), that permits reversible, nontraumatic control of the cardinal biomechanical features of the subluxation: fixation and misalignment. A detailed description of current ELM procedures is presented and practical issues are reviewed such as expense (dollars and time) and construct failure rates during and after the surgical implant procedure. METHOD: Descriptive report of current ELM procedures, refinements to the spinous attachment units (SAUs), and tabulation of costs and failure rates drawn from recent studies. RESULTS: In contrast to the older, 1-piece stainless steel SAUs, new 3-piece titanium SAUs may be reimplanted many times without failure. Consequently, the cost per ELM ranges from $579 to $69, depending on whether the SAUs, links, and screws must be purchased or are already available for implanting. The SAU implant procedure requires between 0.5 and 1.25 hours, depending on the experience of the surgeon. The total construct failure rate for the ELM is 24.2% (6.6% at surgery failure + 17.8% postsurgery failures). This rate is consistent with that reported in spine implant studies with other devices. To date, more than 500 male Sprague-Dawley rats (350-450 g) have been implanted with SAUs for ELM studies at the Palmer Center for Chiropractic Research and the National University of Health Sciences. CONCLUSION: It has been our experience that individuals with basic animal research training will become proficient at producing the ELM after observing 3 to 4 implant procedures and performing 4 to 6 procedures on their own.

Comparison of posteroanterior spinal stiffness measures to clinical and demographic findings at baseline in patients enrolled in a clinical study of spinal manipulation for low back pain.

OBJECTIVE: A system for measuring posterior-to-anterior spinal stiffness (PAS) was developed for use in clinical trials of manipulation for low back pain (LBP). The current report is an analysis of the baseline PAS data, with particular emphasis on relationships between PAS and clinical and demographic characteristics. METHODS: Posterior-to-anterior spinal stiffness measurements were recorded over the spinous processes of the lumbar spines from patients who had LBP. The system uses electronic sensors to record displacement and force, whereas a human operator provides the force of indentation. Clinical and outcome measures were compared with spinal stiffness. RESULTS: We recruited 192 patients (89 female and 103 male; average age, 40.0 years; SD, 9.4 years). The average Roland-Morris score was 9.7 (SD, 3.2) on a 24-point scale. The Visual Analog Scale pain scores were 55.7 (SD, 20.9) on a 100-mm scale. Stiffness values ranged from 4.16 to 39.68 N/mm (mean, 10.80 N/mm; SD, 3.72 N/mm). Females' lumbar spines were, on the average, 2 N/mm more compliant than males (P < .001). CONCLUSIONS: The PAS system of computer-monitored equipment with human operation performed well in this clinical study of LBP. Spinal stiffness was found to be different between males and females, and age and body mass index were related to PAS. We found no significant relationship between the severity or chronicity of the LBP complaint and spinal stiffness. There was little agreement between the stiff or tender segments identified by the clinicians using palpation and the segment that measured most stiff using the PAS device.

Introducing the external link model for studying spine fixation and misalignment: part 2, Biomechanical features.

OBJECTIVES: The purpose of this study was to characterize intervertebral stiffness and alignment changes in the external link model and evaluate it as an experimental mimic for studying the chiropractic subluxation. METHOD: A controlled test-retest design was used to evaluate rats with spine segments linked in 3 alignment configurations and controls that were never linked. Dorsal-to-ventral spine stiffness was measured with a load platform, and flexion/extension misalignment was assessed on lateral radiographs obtained with a spine extension jig. Descriptive statistics were computed for study groups, and multiple linear regression models were used to examine all potential explanatory variables for the response variables "stiffness" and "joint position." RESULTS: Rats tested with links in place had significantly higher dorsal-to-ventral stiffness in the neutral configuration than rats in the flexed configuration. This difference remained after the links were removed. Stiffness after link removal was greater for longer linked periods. Surprisingly, stiffness after link removal was also greater with longer unlinked periods. Longer linked periods also produced greater misalignments during forced spine extension testing. Although link configuration was not a statistically significant predictor of misalignments, longer times after link removal did produce greater misalignments. CONCLUSIONS: This study suggests that the external link model can be a valuable tool for studying the effects of spine fixation and misalignment, 2 cardinal features of what has been historically described as the chiropractic subluxation. Significant residual stiffness and misalignment remained after the links were removed. The progressive course of this lesion is consistent with subluxation theory and clinical chiropractic experience.

Introducing the external link model for studying spine fixation and misalignment: part 1--need, rationale, and applications.

This is the first article in a series introducing a new animal model, the External Link Model that we propose will allow researchers to produce and study spine lesions with the cardinal biomechanical features of the chiropractic subluxation: fixation (hypomobility) and misalignment.

The reliability of a posterior-to-anterior spinal stiffness measuring system in a population of patients with low back pain.

OBJECTIVE: A system for measuring posterior-to-anterior spinal stiffness (PAS) was developed for use in clinical trials of manipulation for low back pain. The reliability of this device is under investigation in this study. METHODS: The PAS system uses electronic sensors to record displacement and force while a human operator provides the force of indentation. A test-retest design was used with measures repeated by the same operator within 5 minutes. Posterior-to-anterior loads were applied to each lumbar spinous process of patients lying prone on a hard flat bench. Force and displacement were recorded and used to calculate PAS. RESULTS: The subjects consisted of 22 males and 14 females; average age was 49.1 years (SD, 14.2). All subjects had low back pain of at least 4 weeks duration, with mean Roland-Morris scores of 7.6 (SD, 3.3). Spinal stiffness ranged from 4 to 26 N/mm (average, 11.2; SD, 3.5). Stiffness in the first and second tests varied on the average by 0.31 N/mm (P = .03). Standard error of the measurement was 1.62 N/mm. The single measures intraclass correlation coefficient (3,1) was 0.790 (95% confidence interval, 0.739-0.832). CONCLUSIONS: The equipment and method produced repeatable results over the short-term. The system may be sensitive enough to detect changes in spinal stiffness that occur with care.

History and overview of theories and methods of chiropractic: a counterpoint.

Spinal manipulation has been used for its therapeutic effects for at least 2500 years. Chiropractic as we know it today began a century ago in a simplistic manner but has developed into to a well-established profession with 33 colleges throughout the world. During the initial, bumpy years, many people thought it had little more value than a placebo. Nevertheless, there have always been satisfied recipients of chiropractic care during the years, and the profession slowly gained prominence--mostly by word of mouth. More recently, personal opinions based on isolated incidents have given way to the results of numerous clinical and basic science studies, primarily regarding low back pain. As of 2002, 43 randomized trials of spinal manipulation for low back pain had been published with 30 showing more improvement than with the comparison treatment, and none showing it to be less effective. Other studies have shown that chiropractic care compared with medical care is safer, costs no more and often costs much less, and has consistently greater patient satisfaction for treatment of similar conditions. Consequently, there is now better public and professional opinion of chiropractic with coverage by insurance companies and government agencies. That trend is likely to continue.

Biomechanical evaluation of four different mattresses.

This study provided an objective, biomechanical comparison of four "top of the line" mattresses from four different manufacturers using two different measurements. One, which has been used in other studies, was pressure distribution patterns-evaluating maximum pressures generated by an individual lying supine on the mattresses. The other was a novel approach developed specifically for this study-quantifying the degree of spinal distortion induced when in the side posture position. Eighteen normal adult males of similar height but in three different weight groups were tested using both of these approaches on each of four mattresses. As expected, greater maximum pressure directly related to subject's weight group and was greater in the pelvic compared to the thoracic region. One mattress did induce significantly lower maximum pressures than the other three in both the pelvic and thoracic regions. Spinal distortion was not reliably different across the four mattresses in five of the seven spine regions evaluated. However, at the T1/T3 and the T6/T8 spinal segments, inconsistent but statistically significant separation between some mattresses was observed.

Chiropractic treatment of temporomandibular disorders using the activator adjusting instrument and protocol.

OBJECTIVE: To describe the chiropractic management of a 30-year-old woman with temporomandibular joint (TMJ) pain and to discuss the general etiology and management of TMJ conditions. CLINICAL FEATURES: The patient suffered from daily unremitting jaw pain for 7 years, which was the apparent sequela of a series of 8 root canals on the same tooth. Pain radiated from her TMJ into her shoulder and was accompanied by headache, tinnitus, decreased hearing, and a feeling of congestion in her right ear. Symptoms were not reduced by medication or other dental treatments. OUTCOME AND INTERVENTION: The patient underwent a series of chiropractic treatments using the instrument and protocol of Activator Methods, International. During the first 5 months, her VAS rating of jaw pain decreased from 60 (on a scale of 0 to 100) to 9, her ability to eat solid foods increased, headache intensity and frequency diminished, and her maximum mouth opening without pain measurement increased from 22 to 28 mm. Overall, 20 months of chiropractic treatment along with 2 concurrent months of massage therapy yielded slow but continual progress that finally resulted in total resolution of all symptoms except some fullness of the right cheek. CONCLUSION: Use of the Activator Methods protocol of chiropractic treatment was beneficial for this patient and merits further study in similar cases.

Spinal manipulation alters electromyographic activity of paraspinal muscles: a descriptive study.

OBJECTIVE: To examine the effect of spinal manipulation on electromyographic (EMG) activity in areas of localized tight muscle bundles of the low back. METHODS: Surface EMG activity was collected from 16 participants in 2 chiropractic offices during the 5 to 10 minutes of the treatment protocol. Electrodes were placed over the 2 sites of greatest paraspinal muscle tension as determined by manual palpation. Spinal manipulation was administered to 8 participants using Activator protocol; the other 8 were treated using Diversified protocol. RESULTS: Electromyographic activity decreased by at least 25% after treatment in 24 of the 31 sites that were monitored. There was less than 25% change at 3 sites and more than 25% increase at 4 sites. Multiple distinct increases and decreases were observed in many data plots. CONCLUSION: The results of this study indicate that manipulation induces a virtually immediate change, usually a reduction, in resting EMG levels in at least some patients with low back pain and tight paraspinal muscle bundles. In some cases, EMG activity increased during the treatment protocol and then usually, but not always, decreased to a level lower than the pretreatment level.