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1.  Association between history and physical examination factors and change in lumbar multifidus muscle thickness after spinal manipulation in patients with low back pain 
Understanding the clinical characteristics of patients with low back pain (LBP) who display improved lumbar multifidus (LM) muscle function after spinal manipulative therapy (SMT) may provide insight into a potentially synergistic interaction between SMT and exercise. Therefore, the purpose of this study was to identify the baseline historical and physical examination factors associated with increased contracted LM muscle thickness one week after SMT. Eighty-one participants with LBP underwent a baseline physical examination and ultrasound imaging assessment of the LM muscle during submaximal contraction before and one week after SMT. The relationship between baseline examination variables and 1-week change in contracted LM thickness was assessed using correlation analysis and hierarchical multiple linear regression. Four variables best predicted the magnitude of increases in contracted LM muscle thickness after SMT. When combined, these variables suggest that patients with LBP, (1) that are fairly acute, (2) have at least a moderately good prognosis without focal and irritable symptoms, and (3) exhibit signs of spinal instability, may be the best candidates for a combined SMT and LSE treatment approach.
doi:10.1016/j.jelekin.2012.03.004
PMCID: PMC3407297  PMID: 22516351
musculoskeletal manipulations; low back pain; muscle contraction; ultrasound; lumbar multifidus
2.  Preliminary investigation of the mechanisms underlying the effects of manipulation: exploration of a multi-variate model including spinal stiffness, multifidus recruitment, and clinical findings 
Spine  2011;36(21):1772-1781.
Study Design
Prospective case series.
Objective
Examine spinal stiffness in subjects with low back pain (LBP) receiving spinal manipulative therapy (SMT), evaluate associations between stiffness characteristics and clinical outcome, and explore a multi-variate model of SMT mechanisms as related to effects on stiffness, lumbar multifidus (LM) recruitment and status on a clinical prediction rule (CPR) for SMT outcomes.
Summary of Background Data
Mechanisms underlying the clinical effects of SMT are poorly understood. Many explanations have been proposed, but few studies have related potential mechanisms to clinical outcomes or considered multiple mechanisms concurrently.
Methods
Subjects with LBP were treated with 2 SMT sessions over 1 week. CPR status was assessed at baseline. Clinical outcome was based on the Oswestry disability index (ODI). Mechanized indentation measures of spinal stiffness and ultrasonic measures of LM recruitment were taken before and after each SMT, and after 1 week. Global and terminal stiffness were calculated. Multivariate regression was used to evaluate the relationship between stiffness variables and percentage ODI improvement. Zero-order correlations among stiffness variables, LM recruitment changes, CPR status, and clinical outcome were examined. Path analysis was used to evaluate a multi-variate model of SMT effects.
Results
Forty-eight subjects (54% female) had complete stiffness data. Significant immediate decreases in global and terminal stiffness occurred post-SMT regardless of outcome. ODI improvement was related to greater immediate decrease in global stiffness (p=0.025), and less initial terminal stiffness (p=0.01). Zero-order correlations and path analysis supported a multi-variate model suggesting clinical outcome of SMT is mediated by improvements in LM recruitment and immediate decrease in global stiffness. Initial terminal stiffness and CPR status may relate to outcome though their relationship with LM recruitment.
Conclusions
The underlying mechanisms explaining the benefits of SMT appear to be multi-factorial. Both spinal stiffness characteristics and LM recruitment changes appear to play a role.
doi:10.1097/BRS.0b013e318216337d
PMCID: PMC3150636  PMID: 21358568
3.  Clinical decision rules, spinal pain classification and prediction of treatment outcome: A discussion of recent reports in the rehabilitation literature 
Clinical decision rules are an increasingly common presence in the biomedical literature and represent one strategy of enhancing clinical-decision making with the goal of improving the efficiency and effectiveness of healthcare delivery. In the context of rehabilitation research, clinical decision rules have been predominantly aimed at classifying patients by predicting their treatment response to specific therapies. Traditionally, recommendations for developing clinical decision rules propose a multistep process (derivation, validation, impact analysis) using defined methodology. Research efforts aimed at developing a “diagnosis-based clinical decision rule” have departed from this convention. Recent publications in this line of research have used the modified terminology “diagnosis-based clinical decision guide.” Modifications to terminology and methodology surrounding clinical decision rules can make it more difficult for clinicians to recognize the level of evidence associated with a decision rule and understand how this evidence should be implemented to inform patient care. We provide a brief overview of clinical decision rule development in the context of the rehabilitation literature and two specific papers recently published in Chiropractic and Manual Therapies.
doi:10.1186/2045-709X-20-19
PMCID: PMC3407693  PMID: 22726639
Diagnosis; Clinical prediction rule; Clinical decision making; Low back pain; Neck pain; Back pain
4.  Low Back Pain in Adolescents: A Comparison of Clinical Outcomes in Sports Participants and Nonparticipants 
Journal of Athletic Training  2010;45(1):61-66.
Abstract
Context:
Back pain is common in adolescents. Participation in sports has been identified as a risk factor for the development of back pain in adolescents, but the influence of sports participation on treatment outcomes in adolescents has not been adequately examined.
Objective:
To examine the clinical outcomes of rehabilitation for adolescents with low back pain (LBP) and to evaluate the influence of sports participation on outcomes.
Design:
Observational study.
Setting:
Outpatient physical therapy clinics.
Patients or Other Participants:
Fifty-eight adolescents (age  =  15.40 ± 1.44 years; 56.90% female) with LBP referred for treatment. Twenty-three patients (39.66%) had developed back pain from sports participation.
Intervention(s):
Patients completed the Modified Oswestry Disability Questionnaire and numeric pain rating before and after treatment. Treatment duration and content were at the clinician's discretion. Adolescents were categorized as sports participants if the onset of back pain was linked to organized sports. Additional data collected included diagnostic imaging before referral, clinical characteristics, and medical diagnosis.
Main Outcome Measure(s):
Baseline characteristics were compared based on sports participation. The influence of sports participation on outcomes was examined using a repeated-measures analysis of covariance with the Oswestry and pain scores as dependent variables. The number of sessions and duration of care were compared using t tests.
Results:
Many adolescents with LBP receiving outpatient physical therapy treatment were involved in sports and cited sports participation as a causative factor for their LBP. Some differences in baseline characteristics and clinical treatment outcomes were noted between sports participants and nonparticipants. Sports participants were more likely to undergo magnetic resonance imaging before referral (P  =  .013), attended more sessions (mean difference  =  1.40, 95% confidence interval [CI]  =  0.21, 2.59, P  =  .022) over a longer duration (mean difference  =  12.44 days, 95% CI  =  1.28, 23.10, P  =  .024), and experienced less improvement in disability (mean Oswestry difference  =  6.66, 95% CI  =  0.53, 12.78, P  =  .048) than nonparticipants. Overall, the pattern of clinical outcomes in this sample of adolescents with LBP was similar to that of adults with LBP.
Conclusions:
Adolescents with LBP due to sports participation received more treatment but experienced less improvement in disability than nonparticipants. This may indicate a worse prognosis for sports participants. Further research is required.
doi:10.4085/1062-6050-45.1.61
PMCID: PMC2808757  PMID: 20064050
spine; athletes; disability
5.  Reduced Quadriceps Activation After Lumbar Paraspinal Fatiguing Exercise 
Journal of Athletic Training  2006;41(1):79-86.
Context: Although poor paraspinal muscle endurance has been associated with less quadriceps activation (QA) in persons with a history of low back pain, no authors have addressed the acute neuromuscular response after lumbar paraspinal fatiguing exercise.
Objective: To compare QA after lumbar paraspinal fatiguing exercise in healthy individuals and those with a history of low back pain.
Design: A 2 × 4 repeated-measures, time-series design.
Setting: Exercise and Sport Injury Laboratory.
Patients or Other Participants: Sixteen volunteers participated (9 males, 7 females; 8 controls and 8 with a history of low back pain; age = 24.1 ± 3.1 years, height = 173.4 ± 7.1 cm, mass = 72.4 ± 12.1 kg).
Intervention(s): Subjects performed 3 sets of isometric lumbar paraspinal fatiguing muscle contractions. Exercise sets continued until the desired shift in lumbar paraspinal electromyographic median power frequency was observed. Baseline QA was compared with QA after each exercise set.
Main Outcome Measure(s): An electric burst was superimposed while subjects performed a maximal quadriceps contraction. We used the central activation ratio to calculate QA = (FMVIC/[FMVIC + FBurst])* 100, where F = force and MVIC = maximal voluntary isometric contractions. Quadriceps electromyographic activity was collected at the same time as QA measurements to permit calculation of median frequency during MVIC.
Results: Average QA decreased from baseline (87.4% ± 8.2%) after the first (84.5% ± 10.5%), second (81.4% ± 11.0%), and third (78.2% ± 12.7%) fatiguing exercise sets. On average, the group with a history of low back pain showed significantly more QA than controls. No significant change in quadriceps median frequency was noted during the quadriceps MVICs.
Conclusions: The quadriceps muscle group was inhibited after lumbar paraspinal fatiguing exercise in the absence of quadriceps fatigue. This effect may be different for people with a history of low back pain compared with healthy controls.
PMCID: PMC1421484  PMID: 16619099
superimposed burst technique; quadriceps muscle inhibition; low back pain
6.  Quadriceps Inhibition After Repetitive Lumbar Extension Exercise in Persons With a History of Low Back Pain 
Journal of Athletic Training  2006;41(3):264-269.
Context: A neuromuscular relationship exists between the lumbar extensor and quadriceps muscles during fatiguing exercise. However, this relationship may be different for persons with low back pain (LBP).
Objective: To compare quadriceps inhibition after isometric, fatiguing lumbar extension exercise between persons with a history of LBP and control subjects.
Design: A 2 × 3 factorial, repeated-measures, time-series design with independent variables of group (persons with a history of LBP, controls) and time (baseline, postexercise set 1, postexercise set 2).
Setting: University research laboratory.
Patients or Other Participants: Twenty-five subjects with a history of LBP were matched by sex, height, and mass to 25 healthy control subjects.
Intervention(s): Electromyography median frequency indexed lumbar paraspinal muscular fatigue while subjects performed 2 sets of isometric lumbar extension exercise. Subjects exercised until a 15% downward shift in median frequency for the first set and a 25% shift for the second set were demonstrated.
Main Outcome Measure(s): Knee extension force was measured while subjects performed an isometric maximal quadriceps contraction. During this maximal effort, a percutaneous electric stimulus was applied to the quadriceps, causing a transient, supramaximal increase in force output. We used the ratio between the 2 forces to estimate quadriceps inhibition. Quadriceps electromyographic activity was recorded during the maximal contractions to compare median frequencies over time.
Results: Both groups exhibited significantly increased quadriceps inhibition after the first (12.6% ± 10.0%, P < .001) and second (15.2% ± 9.7%, P < .001) exercise sets compared with baseline (9.6% ± 9.3%). However, quadriceps inhibition was not different between groups.
Conclusions: Persons with a history of LBP do not appear to be any more or less vulnerable to quadriceps inhibition after fatiguing lumbar extension exercise.
PMCID: PMC1569566  PMID: 17043693
superimposed burst technique; neuromuscular activity; knee
7.  Investigation of Elevated Fear-Avoidance Beliefs for Patients With Low Back Pain: A Secondary Analysis Involving Patients Enrolled in Physical Therapy Clinical Trials 
STUDY DESIGN
Secondary analysis.
OBJECTIVE
To investigate the Fear-Avoidance Beliefs Questionnaire (FABQ) for its ability to predict 6-month outcomes in patients with low back pain (LBP) participating in physical therapy clinical trials.
BACKGROUND
Consistent evidence suggests that fear-avoidance beliefs are predictive of short-term outcomes for patients with LBP. However, proposed cut-off scores have not been widely investigated for longer-term outcomes in samples of patients receiving physical therapy.
METHODS AND MEASURES
Subjects (n = 160) were participants in 2 separate randomized trials that used standard methodology and investigated the efficacy of physical therapy interventions for LBP. Subjects completed baseline measures of pain, disability, fear-avoidance beliefs, and physical impairment. They completed 4 weeks of randomly assigned physical therapy and were reassessed at 6 months with standard examination techniques. The accuracy of previously proposed cut-offs for elevated FABQ scores were determined by independent t tests and chi-square analysis on raw 6-month Oswestry Disability Questionnaire (ODQ) scores, 6-month ODQ change scores, and minimally clinical important difference (MCID) in ODQ scores (6 points). Next, a hierarchical regression model determined which FABQ scale better predicted 6-month ODQ scores after controlling for previously reported prognostic factors and relevant treatment parameters. Last, receiver operating characteristic curve analyses were planned to generate a range of FABQ cut-off scores that predicted 6-month MCID in the ODQ.
RESULTS
The previously reported cut-off score for the FABQ physical activity scale (>14) resulted in 111 (69.4%) of 160 patients being classified as having elevated baseline scores, while the previously reported cut-off score for the FABQ work scale (>29) resulted in 19 (11.9%) of 160 patients being classified as having elevated baseline scores. Patients with elevated FABQ physical activity scale scores (>14) had no significant differences in 6-month ODQ outcomes. Patients with elevated FABQ work scale scores (>29) reported higher 6-month ODQ scores, but were not more likely to have differences in improvement in ODQ outcomes. The final regression model explained 24.4% of the variance in 6-month ODQ scores, with only manipulation and exercise and the FABQ work scale as unique predictors. Fifteen of the subjects (12.7%) had a 6-month change in ODQ that indicated no improvement. The area under the receiver operating characteristic curve for the FABQ physical activity scale predicting this outcome was 0.562 (95% CI: 0.415-0.710) and for the FABQ work scale was 0.694 (95% CI: 0.542-0.846). Cut-off scores were explored for the FABQ work scale only, with positive likelihood ratios that ranged from 1.19 to 5.15 and negative likelihood ratios that ranged from 0.30 to 0.83.
CONCLUSIONS
The FABQ work scale was the better predictor of self-report of disability in this sample of patients participating in physical therapy clinical trials. Future studies are necessary to further test and refine the FABQ work scale as a screening tool alone, and in combination with other examination findings.
LEVEL OF EVIDENCE
Prognosis, Level 2b.
doi:10.2519/jospt.2008.2647
PMCID: PMC2881572  PMID: 18349490
disability; FABQ; Oswestry; prognosis
8.  A randomized clinical trial of the effectiveness of mechanical traction for sub-groups of patients with low back pain: study methods and rationale 
Background
Patients with signs of nerve root irritation represent a sub-group of those with low back pain who are at increased risk of persistent symptoms and progression to costly and invasive management strategies including surgery. A period of non-surgical management is recommended for most patients, but there is little evidence to guide non-surgical decision-making. We conducted a preliminary study examining the effectiveness of a treatment protocol of mechanical traction with extension-oriented activities for patients with low back pain and signs of nerve root irritation. The results suggested this approach may be effective, particularly in a more specific sub-group of patients. The aim of this study will be to examine the effectiveness of treatment that includes traction for patients with low back pain and signs of nerve root irritation, and within the pre-defined sub-group.
Methods/Design
The study will recruit 120 patients with low back pain and signs of nerve root irritation. Patients will be randomized to receive an extension-oriented treatment approach, with or without the addition of mechanical traction. Randomization will be stratified based on the presence of the pre-defined sub-grouping criteria. All patients will receive 12 physical therapy treatment sessions over 6 weeks. Follow-up assessments will occur after 6 weeks, 6 months, and 1 year. The primary outcome will be disability measured with a modified Oswestry questionnaire. Secondary outcomes will include self-reports of low back and leg pain intensity, quality of life, global rating of improvement, additional healthcare utilization, and work absence. Statistical analysis will be based on intention to treat principles and will use linear mixed model analysis to compare treatment groups, and examine the interaction between treatment and sub-grouping status.
Discussion
This trial will provide a methodologically rigorous evaluation of the effectiveness of using traction for patients with low back pain and signs of nerve root irritation, and will examine the validity of a pre-defined sub-grouping hypothesis. The results will provide evidence to inform non-surgical decision-making for these patients.
Trial Registration
This trial has been registered with http://ClinicalTrials.gov: NCT00942227
doi:10.1186/1471-2474-11-81
PMCID: PMC2874768  PMID: 20433733
9.  The cost-effectiveness of a treatment-based classification system for low back pain: design of a randomised controlled trial and economic evaluation 
Background
Systematic reviews have shown that exercise therapy and spinal manipulation are both more effective for low back pain (LBP) than no treatment at all. However, the effects are at best modest. To enhance the clinical outcomes, recommendations are to improve the patient selection process, and to identify relevant subgroups to guide clinical decision-making. One of the systems that has potentials to improve clinical decision-making is a treatment-based classification system that is intended to identify those patients who are most likely to respond to direction-specific exercises, manipulation, or stabilisation exercises.
Methods/Design
The primary aim of this randomised controlled trial will be to assess the effectiveness of a classification-based system. A sample of 150 patients with subacute and chronic LBP who attend a private physical therapy clinic for treatment will be recruited. At baseline, all participants will undergo a standard evaluation by trained research physical therapists and will be classified into one of the following subgroups: direction-specific exercises, manipulation, or stabilisation. The patient will not be informed about the results of the examination. Patients will be randomly assigned to classification-based treatment or usual care according to the Dutch LBP guidelines, and will complete questionnaires at baseline, and 8, 26, and 52 weeks after the start of the treatment. The primary outcomes will be general perceived recovery, functional status, and pain intensity. Alongside this trial, an economic evaluation of cost-effectiveness and cost-utility will be conducted from a societal perspective.
Discussion
The present study will contribute to our knowledge about the effectiveness and cost-effectiveness of classification-based treatment in patients with LBP.
Trial registration
Trial registration number: NTR1176
doi:10.1186/1471-2474-11-58
PMCID: PMC2859390  PMID: 20346133
11.  Jogging Kinematics After Lumbar Paraspinal Muscle Fatigue 
Journal of Athletic Training  2009;44(5):475-481.
Abstract
Context:
Isolated lumbar paraspinal muscle fatigue causes lower extremity and postural control deficits.
Objective:
To describe the change in body position during gait after fatiguing lumbar extension exercises in persons with recurrent episodes of low back pain compared with healthy controls.
Design:
Case-control study.
Setting:
Motion analysis laboratory.
Patients or Other Participants:
Twenty-five recreationally active participants with a history of recurrent episodes of low back pain, matched by sex, height, and mass with 25 healthy controls.
Intervention(s):
We measured 3-dimensional lower extremity and trunk kinematics before and after fatiguing isometric lumbar paraspinal exercise.
Main Outcome Measure(s):
Measurements were taken while participants jogged on a custom-built treadmill surrounded by a 10-camera motion analysis system.
Results:
Group-by-time interactions were observed for lumbar lordosis and trunk angles (P < .05). A reduced lumbar spine extension angle was noted, reflecting a loss of lordosis and an increase in trunk flexion angle, indicating increased forward trunk lean, in healthy controls after fatiguing lumbar extension exercise. In contrast, persons with a history of recurrent low back pain exhibited a slight increase in spine extension, indicating a slightly more lordotic position of the lumbar spine, and a decrease in trunk flexion angles after fatiguing exercise. Regardless of group, participants experienced, on average, greater peak hip extension after lumbar paraspinal fatigue.
Conclusions:
Small differences in response may represent a necessary adaptation used by persons with recurrent low back pain to preserve gait function by stabilizing the spine and preventing inappropriate trunk and lumbar spine positioning.
doi:10.4085/1062-6050-44.5.475
PMCID: PMC2742456  PMID: 19771285
gait analysis; spine
12.  Research priorities for non-pharmacological therapies for common musculoskeletal problems: nationally and internationally agreed recommendations 
Background
Musculoskeletal problems such as low back pain, neck, knee and shoulder pain are leading causes of disability and activity limitation in adults and are most frequently managed within primary care. There is a clear trend towards large, high quality trials testing the effectiveness of common non-pharmacological interventions for these conditions showing, at best, small to moderate benefits. This paper summarises the main lessons learnt from recent trials of the effectiveness of non-pharmacological therapies for common musculoskeletal conditions in primary care and provides agreed research priorities for future clinical trials.
Methods
Consensus development using nominal group techniques through national (UK) and international workshops. During a national Clinical Trials Thinktank workshop in April 2007 in the UK, a group of 30 senior researchers experienced in clinical trials for musculoskeletal conditions and 2 patient representatives debated the possible explanations for the findings of recent high quality trials of non-pharmacological interventions. Using the qualitative method of nominal group technique, these experts developed and ranked a set of priorities for future research, guided by the evidence from recent trials of treatments for common musculoskeletal problems. The recommendations from the national workshop were presented and further ranked at an international symposium (hosted in Canada) in June 2007.
Results
22 recommended research priorities were developed, of which 12 reached consensus as priorities for future research from the UK workshop. The 12 recommendations were reduced to 7 agreed priorities at the international symposium. These were: to increase the focus on implementation (research into practice); to develop national musculoskeletal research networks in which large trials can be sited and smaller trials supported; to use more innovative trial designs such as those based on stepped care and subgrouping for targeted treatment models; to routinely incorporate health economic analysis into future trials; to include more patient-centred outcome measures; to develop a core set of outcomes for new trials of interventions for musculoskeletal problems; and to focus on studies that advance methodological approaches for clinical trials in this field.
Conclusion
A set of research priorities for future trials of non-pharmacological therapies for common musculoskeletal conditions has been developed and agreed through national (UK) and international consensus processes. These priorities provide useful direction for researchers and research funders alike and impetus for improvement in the quality and methodology of clinical trials in this field.
doi:10.1186/1471-2474-10-3
PMCID: PMC2631495  PMID: 19134184
13.  Predictive validity of initial fear avoidance beliefs in patients with low back pain receiving physical therapy: is the FABQ a useful screening tool for identifying patients at risk for a poor recovery? 
European Spine Journal  2007;17(1):70-79.
Several prospective studies examining patients receiving physical therapy support the predictive validity of FABQ subscale scores. This has lead to the proposition that the FABQ would be a useful screening tool, permitting early identification of patients at risk for a poor outcome with an opportunity to modify the treatment accordingly. However, the predictive validity of the FABQ within physical therapy practice has yet to be examined. Predictive validity was analyzed between the FABQ-PA, FABQ-W using both disability and pain as the dependent variables using Pearson correlation coefficients and stepwise hierarchical linear regression modeling controlling for baseline variables. Separate analyses were run for patients with private health insurance and those receiving workers’ compensation. Further analysis of predictive validity was performed by dichotomizing the outcome of physical therapy. Patients were coded as having a poor outcome if they failed to achieve a minimum clinically important change in disability over the course of treatment. The accuracy of previously reported cut-off scales for both the FABQ-W and FABQ-PA were examined for both payor types. Results of the hierarchical linear regression analyses for patients with private insurance showed neither the FABQ-PA nor the FABQ-W score significantly improved the explained variance in change in pain or disability. For patients receiving workers’ compensation, only the FABQ-W subscale score significantly contributed to the model after controlling for the other baseline variables for both changes in disability and pain. Only the FABQ-W subscale was predictive of poor outcome and this was only identified in the worker’s compensation group. The results suggest that the work subscale of the FABQ might be an appropriate screening tool to identify patients with work-related LBP who are at risk for a poor outcome with routine physical therapy. Neither FABQ subscale was predictive of outcome for patients with private insurance, and the use of the FABQ, as a screening tool for patients with non-work-related LBP was not supported.
doi:10.1007/s00586-007-0511-y
PMCID: PMC2365529  PMID: 17926072
Disability; Fear-avoidance beliefs; Low back pain; Outcome; Pain; Predictive validity
14.  Accuracy of the clinical examination to predict radiographic instability of the lumbar spine 
European Spine Journal  2005;14(8):743-750.
Forty-nine patients with low-back pain referred for flexion-extension radiographs due to suspicion of lumbar instability were studied to examine the relationship between the clinical presentation and the presence of radiographic instability of the lumbar spine. Patients had a mean age of 39.2 (±11.3) years, with a mean Oswestry score of 20.4% (±13.3). The median duration of symptoms was 78 days. All patients underwent both a radiographic and clinical examination. The reliability of the radiographic variables was high, while the reliability of clinical variables ranged from moderate to good. Twenty-eight patients (57%) had radiographic instability based on published norms. Clinical variables related to the presence of radiographic instability were age, lumbar flexion range of motion, total extension range of motion, the Beighton scale for general ligamentous laxity, and segmental intervertebral motion testing. The presence of at least 53° of lumbar flexion or a lack of hypomobility with intervertebral motion testing resulted in a positive likelihood ratio of 4.3 (95% CI: 1.8, 10.6), for predicting radiographic instability. The results of this study indicate that various factors from the clinical examination are useful for predicting radiographic instability. If the findings of this study can be replicated, these clinical factors could be used to inform treatment decision-making without a sole reliance on radiographic assessment.
doi:10.1007/s00586-004-0803-4
PMCID: PMC3489248  PMID: 16047211
Low-back pain; Instability; Diagnosis; Radiographic assessment
15.  Lumbar segmental mobility disorders: comparison of two methods of defining abnormal displacement kinematics in a cohort of patients with non-specific mechanical low back pain 
Background
Lumbar segmental rigidity (LSR) and lumbar segmental instability (LSI) are believed to be associated with low back pain (LBP), and identification of these disorders is believed to be useful for directing intervention choices. Previous studies have focussed on lumbar segmental rotation and translation, but have used widely varying methodologies. Cut-off points for the diagnosis of LSR & LSI are largely arbitrary. Prevalence of these lumbar segmental mobility disorders (LSMDs) in a non-surgical, primary care LBP population has not been established.
Methods
A cohort of 138 consecutive patients with recurrent or chronic low back pain (RCLBP) were recruited in this prospective, pragmatic, multi-centre study. Consenting patients completed pain and disability rating instruments, and were referred for flexion-extension radiographs. Sagittal angular rotation and sagittal translation of each lumbar spinal motion segment was measured from the radiographs, and compared to a reference range derived from a study of 30 asymptomatic volunteers. In order to define reference intervals for normal motion, and define LSR and LSI, we approached the kinematic data using two different models. The first model used a conventional Gaussian definition, with motion beyond two standard deviations (2sd) from the reference mean at each segment considered diagnostic of rotational LSMD and translational LSMD. The second model used a novel normalised within-subjects approach, based on mean normalised contribution-to-total-lumbar-motion. An LSMD was then defined as present in any segment that contributed motion beyond 2sd from the reference mean contribution-to-normalised-total-lumbar-motion. We described reference intervals for normal segmental mobility, prevalence of LSMDs under each model, and the association of LSMDs with pain and disability.
Results
With the exception of the conventional Gaussian definition of rotational LSI, LSMDs were found in statistically significant prevalences in patients with RCLBP. Prevalences at both the segmental and patient level were generally higher using the normalised within-subjects model (2.8 to 16.8% of segments; 23.3 to 35.5% of individuals) compared to the conventional Gaussian model (0 to 15.8%; 4.7 to 19.6%). LSMDs are associated with presence of LBP, however LSMDs do not appear to be strongly associated with higher levels of pain or disability compared to other forms of non-specific LBP.
Conclusion
LSMDs are a valid means of defining sub-groups within non-specific LBP, in a conservative care population of patients with RCLBP. Prevalence was higher using the normalised within-subjects contribution-to-total-lumbar-motion approach.
doi:10.1186/1471-2474-7-45
PMCID: PMC1550717  PMID: 16709258
16.  Contribution of Hamstring Fatigue to Quadriceps Inhibition Following Lumbar Extension Exercise 
The purpose of this study was to determine the contribution of hamstrings and quadriceps fatigue to quadriceps inhibition following lumbar extension exercise. Regression models were calculated consisting of the outcome variable: quadriceps inhibition and predictor variables: change in EMG median frequency in the quadriceps and hamstrings during lumbar fatiguing exercise. Twenty-five subjects with a history of low back pain were matched by gender, height and mass to 25 healthy controls. Subjects performed two sets of fatiguing isometric lumbar extension exercise until mild (set 1) and moderate (set 2) fatigue of the lumbar paraspinals. Quadriceps and hamstring EMG median frequency were measured while subjects performed fatiguing exercise. A burst of electrical stimuli was superimposed while subjects performed an isometric maximal quadriceps contraction to estimate quadriceps inhibition after each exercise set. Results indicate the change in hamstring median frequency explained variance in quadriceps inhibition following the exercise sets in the history of low back pain group only. Change in quadriceps median frequency explained variance in quadriceps inhibition following the first exercise set in the control group only. In conclusion, persons with a history of low back pain whose quadriceps become inhibited following lumbar paraspinal exercise may be adapting to the fatigue by using their hamstring muscles more than controls.
Key PointsA neuromuscular relationship between the lumbar paraspinals and quadriceps while performing lumbar extension exercise may be influenced by hamstring muscle fatigue.QI following lumbar extension exercise in persons with a history of LBP group may involve significant contribution from the hamstring muscle group.More hamstring muscle contribution may be a necessary adaptation in the history of LBP group due to weaker and more fatigable lumbar extensors.
PMCID: PMC3818676  PMID: 24198683
Superimposed burst technique; electromyography; spectral median frequency; correlation and regression; low back pain
17.  Comparison of the effectiveness of three manual physical therapy techniques in a subgroup of patients with low back pain who satisfy a clinical prediction rule: Study protocol of a randomized clinical trial [NCT00257998] 
Background
Recently a clinical prediction rule (CPR) has been developed and validated that accurately identifies patients with low back pain (LBP) that are likely to benefit from a lumbo-pelvic thrust manipulation. The studies that developed and validated the rule used the identical manipulation procedure. However, recent evidence suggests that different manual therapy techniques may result similar outcomes. The purpose of this study is to investigate the effectiveness of three different manual therapy techniques in a subgroup of patient with low back pain that satisfy the CPR.
Methods/Design
Consecutive patients with LBP referred to physical therapy clinics in one of four geographical locations who satisfy the CPR will be invited to participate in this randomized clinical trial. Subjects who agree to participate will undergo a standard evaluation and complete a number of patient self-report questionnaires including the Oswestry Disability Index (OSW), which will serve as the primary outcome measure. Following the baseline examination patients will be randomly assigned to receive the lumbopelvic manipulation used in the development of the CPR, an alternative lumbar manipulation technique, or non-thrust lumbar mobilization technique for the first 2 visits. Beginning on visit 3, all 3 groups will receive an identical standard exercise program for 3 visits (visits 3,4,5). Outcomes of interest will be captured by a therapist blind to group assignment at 1 week (3rd visit), 4 weeks (6th visit) and at a 6-month follow-up. The primary aim of the study will be tested with analysis of variance (ANOVA) using the change in OSW score from baseline to 4-weeks (OSWBaseline – OSW4-weeks) as the dependent variable. The independent variable will be treatment with three levels (lumbo-pelvic manipulation, alternative lumbar manipulation, lumbar mobilization).
Discussion
This trial will be the first to investigate the effectiveness of various manual therapy techniques for patients with LBP who satisfy a CPR.
doi:10.1186/1471-2474-7-11
PMCID: PMC1421401  PMID: 16472379
18.  Pragmatic application of a clinical prediction rule in primary care to identify patients with low back pain with a good prognosis following a brief spinal manipulation intervention 
BMC Family Practice  2005;6:29.
Background
Patients with low back pain are frequently encountered in primary care. Although a specific diagnosis cannot be made for most patients, it is likely that sub-groups exist within the larger entity of nonspecific low back pain. One sub-group that has been identified is patients who respond rapidly to spinal manipulation. The purpose of this study was to examine the association between two factors (duration and distribution of symptoms) and prognosis following a spinal manipulation intervention.
Methods
Data were taken from two previously published studies. Patients with low back pain underwent a standardized examination, including assessment of duration of the current symptoms in days, and the distal-most distribution of symptoms. Based on prior research, patients with symptoms of <16 days duration and no symptoms distal to the knee were considered to have a good prognosis following manipulation. All patients underwent up to two sessions of spinal manipulation treatment and a range of motion exercise. Oswestry disability scores were recorded before and after treatment. If ≥ 50% improvement on the Oswestry was achieved, the intervention was considered a success. Sensitivity, specificity, and positive likelihood ratio were calculated for the association of the two criteria with the outcome of the treatment.
Results
141 patients (49% female, mean age = 35.5 (± 11.1) years) participated. Mean pre- and post-treatment Oswestry scores were 41.9 (± 10.9) and 24.1 (± 14.2) respectively. Sixty-three subjects (45%) had successful treatment outcomes. The sensitivity of the two criteria was 0.56 (95% CI: 0.43, 0.67), specificity was 0.92 (95% CI: 0.84, 0.96), and the positive likelihood ratio was 7.2 (95% CI: 3.2, 16.1).
Conclusion
The results of this study demonstrate that two factors; symptom duration of less than 16 days, and no symptoms extending distal to the knee, were associated with a good outcome with spinal manipulation.
doi:10.1186/1471-2296-6-29
PMCID: PMC1180432  PMID: 16018809

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