Steven Z. George

The mechanisms of manual therapy in the treatment of musculoskeletal pain: a comprehensive model.

Prior studies suggest manual therapy (MT) as effective in the treatment of musculoskeletal pain; however, the mechanisms through which MT exerts its effects are not established. In this paper we present a comprehensive model to direct future studies in MT. This model provides visualization of potential individual mechanisms of MT that the current literature suggests as pertinent and provides a framework for the consideration of the potential interaction between these individual mechanisms. Specifically, this model suggests that a mechanical force from MT initiates a cascade of neurophysiological responses from the peripheral and central nervous system which are then responsible for the clinical outcomes. This model provides clear direction so that future studies may provide appropriate methodology to account for multiple potential pertinent mechanisms.

The effect of a fear-avoidance-based physical therapy intervention for patients with acute low back pain: results of a randomized clinical trial.

Study Design. A randomized clinical trial with 4-week and 6-month follow-up periods. Objective. To compare the effect of a fear-avoidance–based physical therapy intervention with standard care physical therapy for patients with acute low back pain. Summary of Background Data. The disability reduction strategy of secondary prevention involves providing specific treatment for patients that are likely to have chronic disability from low back pain. Previous studies have indicated that elevated fear-avoidance beliefs are a precursor to chronic disability from low back pain. However, the effectiveness of physical therapy intervention based on a fear-avoidance model is unknown. Methods. Sixty-six consecutive patients referred to physical therapy with low back pain of less than 8 weeks’ duration were randomly assigned to receive fear-avoidance–based physical therapy (n = 34) or standard care physical therapy (n = 32). The intervention period lasted 4 weeks for this study. Disability, pain intensity, and fear-avoidance beliefs measures were recorded before and after treatment. A 6-month follow-up of the same measures was obtained by mail. Results. An intention-to-treat principle (last value forward) was used for data analyses that tested the primary and secondary hypotheses. The prediction of disability at 4 weeks and 6 months after treatment was significantly improved by considering the interaction between the type of treatment and the initial level of fear-avoidance beliefs. Both groups had significant within group improvements for disability and pain intensity. The fear-avoidance treatment group had a significant improvement in fear-avoidance beliefs, and fear-avoidance beliefs about physical activity were significantly lower than the standard care group at 4 weeks and 6 months after treatment. Conclusion. Patients with elevated fear-avoidance beliefs appeared to have less disability from fear-avoidance–based physical therapy when compared to those receiving standard care physical therapy. Patients with lower fear-avoidance beliefs appeared to have more disability from fear-avoidance–based physical therapy, when compared to those receiving standard care physical therapy. In addition, physical therapy supplemented with fear-avoidance–based principles contributed to a positive shift in fear-avoidance beliefs.

The use of a classification approach to identify subgroups of patients with acute low back pain. Interrater reliability and short-term treatment outcomes.

Study Design. A prospective, consecutive, cohort study of patients with acute low back pain classified into subgroups based on examination data and treated with a specific treatment approach. Objective. To calculate the interrater reliability of a classification system, and to compare initial patient characteristics and outcomes of physical therapy treatment when a classification approach is used. Summary of Background Data. Classification of patients with low back pain into homogeneous subgroups has been identified as a research priority. Identifying relevant subgroups of patients could improve clinical outcomes and research efficiency. Methods. Consecutive patients referred to physical therapy for treatment of acute low back pain were evaluated and classified into one of four subgroups (immobilization, mobilization, specific exercise, or traction) before treatment. Physical therapy treatment was based on the patient’s classification. The classifications were compared for initial patient characteristics, frequency and duration of physical therapy, and improvement in Oswestry scores. Results. In this study, 120 patients were evaluated and classified. Analysis of interrater reliability showed a kappa value of 0.56. Differences were found among the classifications for age, initial Oswestry score, history of low back pain, symptom distribution, and average change in Oswestry score with treatment. Conclusions. Reaching a consensus regarding relevant patient subgroups requires data on the reliability and validity of existing classification systems. Further work is required to validate improvement in treatment outcomes using a classification approach.

The Association of Pain and Fear of Movement/Reinjury With Function During Anterior Cruciate Ligament Reconstruction Rehabilitation

STUDY DESIGN Cross-sectional. OBJECTIVES To measure fear of movement/reinjury levels and determine the association with function at different timeframes during anterior cruciate ligament (ACL) reconstruction rehabilitation. We hypothesized that fear of movement/reinjury would decrease during rehabilitation and be inversely related with function. BACKGROUND Fear of movement/reinjury can prevent return to sports after ACL reconstruction, but it has not been studied during rehabilitation. METHODS AND MEASURES Demographic data and responses on the shortened version of Tampa Scale for Kinesiophobia (TSK-11), 8-Item Short-Form Health Survey (SF-8), and International Knee Documentation Committee (IKDC) subjective form were extracted from a clinical database for 97 patients in the first year after ACL reconstruction. Three groups were formed: group 1, less than or equal to 90 days; group 2, 91 to 180 days; group 3: 181 to 372 days post-ACL reconstruction. Group differences in TSK-11 score, SF-8 bodily pain rating, and IKDC scores were determined. Hierarchical linear regression models were created for each group, with IKDC score as the dependent variable and demographic factors, SF-8 bodily pain rating, and TSK-11 score as independent variables. RESULTS TSK-11 score was higher in group 1 than in group 3 (P < .05). Across the groups, SF-8 bodily pain rating decreased (P < .001) and IKDC score increased (P < .001). SF-8 bodily pain rating was a significant factor in the regression model for all groups, whereas TSK-11 score only contributed to the regression model in group 3 (partial correlation, -0.529). CONCLUSIONS Pain was consistently associated with function across the timeframes studied. Fear of movement/reinjury levels appear to decrease during ACL reconstruction rehabilitation and are associated with function in the timeframe when patients return to sports. LEVEL OF EVIDENCE Prognosis, level 4.

Evidence for a biopsychosocial influence on shoulder pain: Pain catastrophizing and catechol-O-methyltransferase (COMT) diplotype predict clinical pain ratings

&NA; The experience of pain is believed to be influenced by social, cultural, environmental, psychological, and genetic factors. Despite this assertion, few studies have included clinically relevant pain phenotypes when investigating interactions among these variables. This study investigated whether psychological variables specific to fear‐avoidance models and catechol‐O‐methyltransferase (COMT) genotype influenced pain ratings for a cohort of patients receiving operative treatment of shoulder pain. Patients (n = 58) completed questionnaires and had COMT genotype determined pre‐operatively. Then, shoulder pain ratings were collected 3–5 months post‐operatively. This cohort consisted of 24 females and 34 males, with mean age of 50.3 (SD = 15.0) and pre‐operative pain rating of 4.5/10 (SD = 1.8). The frequency of COMT diplotypes was 34 with “high COMT activity” (LPS group) and 24 with “low COMT activity” (APS/HPS group). Preliminary analysis indicated that of all the fear‐avoidance variables considered (fear of pain, kinesiophobia, pain catastrophizing, and anxiety), only pain catastrophizing was a unique contributor to clinical pain ratings. A hierarchical regression model indicated that an interaction between pain catastrophizing and COMT diplotype contributed additional variance in pre‐operative pain ratings. The pain catastrophizing × COMT diplotype interaction demonstrated predictive validity as patients with high pain catastrophizing and low COMT activity (APS/HPS group) were more likely (RR = 6.8, 95% CI = 2.8–16.7) to have post‐operative pain ratings of 4.0/10 or higher. Our findings suggest that an interaction between pain catastrophizing and COMT diplotype has the potential to influence pain ratings in patients seeking operative treatment of their shoulder pain.

Immediate effects of spinal manipulation on thermal pain sensitivity: an experimental study.

BackgroundThe underlying causes of spinal manipulation hypoalgesia are largely unknown. The beneficial clinical effects were originally theorized to be due to biomechanical changes, but recent research has suggested spinal manipulation may have a direct neurophysiological effect on pain perception through dorsal horn inhibition. This study added to this literature by investigating whether spinal manipulation hypoalgesia was: a) local to anatomical areas innervated by the lumbar spine; b) correlated with psychological variables; c) greater than hypoalgesia from physical activity; and d) different for A-delta and C-fiber mediated pain perception.MethodsAsymptomatic subjects (n = 60) completed baseline psychological questionnaires and underwent thermal quantitative sensory testing for A-delta and C-fiber mediated pain perception. Subjects were then randomized to ride a stationary bicycle, perform lumbar extension exercise, or receive spinal manipulation. Quantitative sensory testing was repeated 5 minutes after the intervention period. Data were analyzed with repeated measures ANOVA and post-hoc testing was performed with Bonferroni correction, as appropriate.ResultsSubjects in the three intervention groups did not differ on baseline characteristics. Hypoalgesia from spinal manipulation was observed in lumbar innervated areas, but not control (cervical innervated) areas. Hypoalgesic response was not strongly correlated with psychological variables. Spinal manipulation hypoalgesia for A-delta fiber mediated pain perception did not differ from stationary bicycle and lumbar extension (p > 0.05). Spinal manipulation hypoalgesia for C-fiber mediated pain perception was greater than stationary bicycle riding (p = 0.040), but not for lumbar extension (p = 0.105).ConclusionLocal dorsal horn mediated inhibition of C-fiber input is a potential hypoalgesic mechanism of spinal manipulation for asymptomatic subjects, but further study is required to replicate this finding in subjects with low back pain.

A comparison of fear-avoidance beliefs in patients with lumbar spine pain and cervical spine pain

Study Design. A prospective consecutive cohort study of patients with cervical spine pain and patients with lumbar spine pain referred to an academic medical center. Objectives. To investigate the presence of fear-avoidance beliefs in a sample of patients with cervical spine pain and to compare the association of pain intensity, disability, and fear-avoidance beliefs in patients with cervical spine pain with that in patients with lumbar spine pain. Summary of Background Data. Fear-avoidance beliefs are a specific psychosocial variable involved in the development of disability from low back pain. Psychosocial variables are believed to play a role in cervical disability, but specific variables have not been investigated. Methods. Consecutive patients referred to a multidisciplinary center completed self-reports of disability, pain intensity, and fear-avoidance beliefs during an initial evaluation session. Gender, type of symptom onset, acuity, and payer source were also recorded. Associations between disability, pain intensity, and fear-avoidance beliefs were investigated in patients with cervical spine pain and patients with lumbar spine pain. Results. In all, 163 patients completed the self-reports and were included in this study. Weaker relations between fear-avoidance beliefs and disability were found in patients with cervical pain than in those with lumbar pain. Significant differences in fear-avoidance beliefs were found for gender, type of symptom onset, and payer source (workers’ compensation, auto insurance, and traditional insurance). Conclusion. The associations among fear-avoidance beliefs, pain intensity, and disability differed between patients with cervical spine pain and patients with lumbar spine pain. Fear-avoidance beliefs were significantly different in subgroups of patients.

Spinal Manipulative Therapy Has an Immediate Effect on Thermal Pain Sensitivity in People With Low Back Pain: A Randomized Controlled Trial

Background Current evidence suggests that spinal manipulative therapy (SMT) is effective in the treatment of people with low back pain (LBP); however, the corresponding mechanisms are unknown. Hypoalgesia is associated with SMT and is suggestive of specific mechanisms. Objective The primary purpose of this study was to assess the immediate effects of SMT on thermal pain perception in people with LBP. A secondary purpose was to determine whether the resulting hypoalgesia was a local effect and whether psychological influences were associated with changes in pain perception. Design This study was a randomized controlled trial. Setting A sample of convenience was recruited from community and outpatient clinics. Participants Thirty-six people (10 men, 26 women) currently experiencing LBP participated in the study. The average age of the participants was 32.39 (SD=12.63) years, and the average duration of LBP was 221.79 (SD=365.37) weeks. Intervention and Measurements Baseline demographic and psychological measurements were obtained, followed by quantitative sensory testing to assess temporal summation and Aδ fiber–mediated pain perception. Next, participants were randomly assigned to ride a stationary bicycle, perform low back extension exercises, or receive SMT. Finally, the same quantitative sensory testing protocol was reassessed to determine the immediate effects of each intervention on thermal pain sensitivity. Results Hypoalgesia to Aδ fiber–mediated pain perception was not observed. Group-dependent hypoalgesia of temporal summation specific to the lumbar innervated region was observed. Pair-wise comparisons indicated significant hypoalgesia in participants who received SMT, but not in those who rode a stationary bicycle or performed low back extension exercises. Psychological factors did not significantly correlate with changes in temporal summation in participants who received SMT. Limitations Only immediate effects of SMT were measured, so the authors are unable to comment on whether the inhibition of temporal summation is a lasting effect. Furthermore, the authors are unable to comment on the relationship between their findings and changes in clinical pain. Conclusions Inhibition of Aδ fiber–mediated pain perception was similar for all groups. However, inhibition of temporal summation was observed only in participants receiving SMT, suggesting a modulation of dorsal horn excitability that was observed primarily in the lumbar innervated area.

The influence of expectation on spinal manipulation induced hypoalgesia: An experimental study in normal subjects

BackgroundThe mechanisms thorough which spinal manipulative therapy (SMT) exerts clinical effects are not established. A prior study has suggested a dorsal horn modulated effect; however, the role of subject expectation was not considered. The purpose of the current study was to determine the effect of subject expectation on hypoalgesia associated with SMT.MethodsSixty healthy subjects agreed to participate and underwent quantitative sensory testing (QST) to their leg and low back. Next, participants were randomly assigned to receive a positive, negative, or neutral expectation instructional set regarding the effects of a specific SMT technique on pain perception. Following the instructional set, all subjects received SMT and underwent repeat QST.ResultsNo interaction (p = 0.38) between group assignment and pain response was present in the lower extremity following SMT; however, a main effect (p < 0.01) for hypoalgesia was present. A significant interaction was present between change in pain perception and group assignment in the low back (p = 0.01) with participants receiving a negative expectation instructional set demonstrating significant hyper algesia (p < 0.01).ConclusionThe current study replicates prior findings of c- fiber mediated hypoalgesia in the lower extremity following SMT and this occurred regardless of expectation. A significant increase in pain perception occurred following SMT in the low back of participants receiving negative expectation suggesting a potential influence of expectation on SMT induced hypoalgesia in the body area to which the expectation is directed.

A Randomized Trial of Behavioral Physical Therapy Interventions for Acute and Sub-Acute Low Back Pain (NCT00373867)

Abstract Psychological factors consistent with fear‐avoidance models are associated with the development of chronic low back pain (LBP). As a result, graded activity (GA) and graded exposure (GX) have been suggested as behavioral treatment options. This clinical trial compared the effectiveness of treatment‐based classification (TBC) physical therapy alone to TBC augmented with GA or GX for patients with acute and sub‐acute LBP. Our primary hypothesis was that GX would be most effective for those with elevated pain‐related fear. In total, 108 patients enrolled in this clinical trial and were randomly assigned to receive TBC, GA, or GX. Outcomes were assessed by a blinded evaluator at 4 weeks and by mail at 6 months. The primary outcomes for this trial were disability and pain intensity, and the secondary outcomes were fear‐avoidance beliefs, pain catastrophizing, and physical impairment. There were no differences in 4‐week and 6‐month outcomes for reduction of disability, pain intensity, pain catastrophizing, and physical impairment. GX and TBC were associated with larger reductions in fear‐avoidance beliefs at 6 months only. Six‐month reduction in disability was associated with reduction in pain intensity, while 6‐month reduction in pain intensity was associated with reductions in fear‐avoidance beliefs and pain catastrophizing. This trial suggests that supplementing TBC with GA or GX was not effective for improving important outcomes related to the development of chronic LBP.