Symptom-Specific Psychophysiological Responses in Chronic Pain Patients.

Symptom-specific psychophysiological responding was assessed in 20 chronic back pain patients, 20 patients suffering from temporomandibular pain and dysfunction, and 20 matched healthy controls. Surface EMG from the lower and upper back, the masseter, and the biceps muscles, and heart rate and skin conductance level were continuously recorded during adaptation, resting baseline, and stressful and neutral imagery phases. Univariate and multivariate analyses of variance were performed on raw data as well as data corrected for autocorrelation. The results showed significantly higher EMG reactivity which was lateralized to the left side at the patients' site of pain but not distal sites. This hyperreactivity was observed only during stressful imagery. The healthy controls displayed a significantly higher response in heart rate, but skin conductance level was not significantly different. The results are interpreted as indicative of idiosyncratic muscular response patterns to personally relevant situations at the site of pain in patients suffering from chronic muscular pain.     

The impact of chronic pain on the self-concept.

Compared self-concepts of three groups, medical patients, chronic low back pain patients and chronic head pain patients (N = 60) to determine (1) whether chronic pain patients have self-perceptions that differ from other medical patients; (2) whether changes in self-perception are limited to physical attributes and capacities; and finally (3) whether persons who suffer different types of chronic pain would have differing self-concepts. Significantly lower self-concepts were obtained from groups of head pain and low back pain patients. Self-concept patterns for the two pain groups were quite similar with the exception of two self-concept components that were significantly lower for the head pain group. Differences were explained in terms of loss of many normal functions and disruption of normal life-styles. Implications for treatment of pain patients and for training of health professionals were discussed.     

Trunk muscle co-ordination during gait: Relationship between muscle function and acute low back pain

Low back pain costs billions of Euros annually in all industrialized countries. Often radiological diagnosis fails to give evidence of the pathogenesis of low back pain. Although psychophysiological characteristics have an influence, it seems that insufficient muscular spinal stabilization may play the major role in the development of low back pain. Assessment of trunk muscle stabilization activity during everyday activities is rare. Therefore, in this study healthy persons were investigated during walking on a treadmill at a speed of 4 km/h. Women (n = 16) with no history of back pain were investigated before and after a static loading situation of the spine, i.e. while wearing a waistcoat. After this loading situation four women developed pain (pain subjects). Surface EMG (SEMG) was taken from five trunk muscles of both sides. Grand averaged amplitude curves over stride, amplitude normalized curves and variation between all included strides were calculated for all muscles and subjects, respectively. The normal range of all calculated parameters was defined within the span between the 5th and the 95th percentiles of all pain free subjects. Data were evaluated according to deviations from the normal range.

Already before the load situation, pain subjects showed considerable deviations from the normal range, mainly of their abdominal muscles. There was no relationship between magnitude of deviation and pain intensity, but perceived exertion was highest in those subjects who showed the most symptoms in terms of number of muscles being identified as considerably deviating from the normal range. No specific “dysfunction pattern” could be identified, which argues for highly individual mechanisms instead of a single target muscle. The results suggest cumulative effects of different disturbance levels resulting in acute back pain. Since deviations could be identified already before the pain occurred, disturbed muscle function seems to be a risk factor for developing back pain. Further investigations aimed at clear identification of and, as a second step, correction of muscle function are necessary.     

Walking with chronic non-specific low back pain – A failed strategy: What can we learn from sports?

The present theoretical consideration is focused on the different behaviours of patients with chronic non-specific low back pain and healthy people when walking. The ground reaction force pattern and its direct influence on the success of the applied strategy are of special interest. This consideration does not clarify whether or not and to what limit the indicated pattern is the main cause or compensatory effect of chronic non-specific low back pain. It is known that pain patients exhibit divergent walking patterns. In addition to a shorter stride, the relationship between swing-to-stance phase shifts in the direction of stance. This strategy should contribute to an improvement in the control. Simultaneously, the impact and the forces should be reduced. Recent studies refer to different activation behaviours of the bi-articular Musculus biceps femoris. According to our analysis, this muscle owns a key function concerning force transmission. The type of force transmission immediately influences system loading. The strategy exhibited by patients with chronic non-specific back pain fails due to false activations, in particular false activations of the M. biceps femoris. The essential objective of the strategy for reducing the maxima of the applied forces, as well as to distribute the force over a longer period of time, was implemented; however, it could be shown that the increase in the maximum force is clearly reached early. Such a fast development in force is equivalent to higher loadings to the human system. This concerns visco-elastic structures in particular. Due to the fast increasing forces, these structures possess low or insufficient damping properties. If our hypothesis of the failed strategy holds true, it might be the basis for new therapeutic approaches, as well as diagnostics involving non-specific low back pain.     

Transdermal fentanyl for chronic low back pain

Purpose

Chronic low back pain is a common clinical problem. As medication, non-steroidal anti-inflammatory drugs are generally used; however, they are sometimes non-effective. Recently, opioids have been used for the treatment of chronic low back pain, and since 2010, transdermal fentanyl has been used to treat chronic non-cancer pain in Japan. The purpose of the current study was to examine the efficacy of transdermal fentanyl in the treatment of chronic low back pain.

Materials and Methods

This study included patients (n=62) that suffered from chronic low back pain and were non-responsive to non-steroidal anti-inflammatory drugs. Their conditions consisted of non-specific low back pain, multiple back operations, and specific low back pain awaiting surgery. Patients were given transdermal fentanyl for chronic low back pain. Scores of the visual analogue scale and the Oswestry Disability Index, as well as adverse events were evaluated before and after therapy.

Results

Overall, visual analogue scale scores and Oswestry Disability Index scores improved significantly after treatment. Transdermal fentanyl (12.5 to 50 µg/h) was effective in reducing low back pain in 45 of 62 patients; however, it was not effective in 17 patients. Patients who experienced the most improvement were those with specific low back pain awaiting surgery. Adverse events were seen in 40% of patients (constipation, 29%; nausea, 24%; itching, 24%).

Conclusion

Disability Index scores in 73% of patients, especially those with specific low back pain awaiting surgery; however, it did not decrease pain in 27% of patients, including patients with non-specific low back pain or multiple back operations.     

Attributional style of depressed chronic low back patients

This study used the Attributional Style Questionnaire to study the attributional styles of depressed and nondepressed chronic low back pain patients (N = 91) in order to test the Revised Learned Helplessness model's prediction of differences between the two. The results partly supported the hypothesis; an internal, stable, global style for negative events distinguished the depressed group from the nondepressed, but there were no differences in attributional style for positive events. The findings are consistent with recent reviews of the literature that have reported general support for the negative outcome style, but consistent failure to confirm the predictions associated with positive outcome style. In addition, the attributional style was not common to all subjects in the depressed group, which suggested that other factors may be involved in the development of different subtypes of depression. Implications for studying attributional aspects of depression and chronic low back pain are discussed.     

Comparing physical and behavior therapy for chronic low back pain on physical abilities,psychological distress,and patients' perceptions

A treatment-outcome study was conducted to study the impact of behavior and physical therapy on components of the chronic low back pain syndrome. Eighteen patients received behavior therapy and 15 patients received physical therapy. All patients had at least a 6-month history of seeking treatment for chronic low back pain. Prior to treatment patients were assessed in four principal areas of functioning: (1) physical abilities; (2) current physical functioning; (3) psychological and psychosocial functioning; and (4) pain intensity and pain perception. Treatments were conducted in a group (five to eight patients) outpatient setting. Both behavior therapy and physical therapy groups met for 10-weekly sessions, each lasting 2 hr. Behavior therapy was designed to address the environmental, social, and emotional components of the low back pain syndrome as well as the depression and decreased activity that result from chronic low back pain. Physical therapy was based upon traditional rehabilitation theory and was designed to improve low back function. Patients were reevaluated at posttreatment, 6 months, and 1 year. The results showed a general improvement for patients in both groups and a few treatment-specific differences in outcome measures.This research was supported by the Veterans Administration Medical Research Program. Portions of this paper were read at the Annual Meeting of the American Pain Society, New York, September 1980.     

A controlled trial of corticosteroid injections into facet joints for chronic low back pain.

BACKGROUND. Chronic low back pain is a common problem with many treatments, few of which have been rigorously evaluated. This randomized, placebo-controlled trial was designed to evaluate the efficacy of injections of corticosteroid into facet joints to treat chronic low back pain. METHODS. Patients with chronic low back pain who reported immediate relief of their pain after injections of local anesthetic into the facet joints between the fourth and fifth lumbar vertebrae and the fifth lumbar and first sacral vertebrae were randomly assigned to receive under fluoroscopic guidance injections of either methylprednisolone acetate (20 mg; n = 49) or isotonic saline (n = 48) in the same facet joints. Ninety-five patients were followed for six months and their condition assessed with scales of pain severity, back mobility, and limitation of function. RESULTS. After one month, none of the outcome measures evaluating pain, functional status, and back flexion differed clinically or statistically between the two study groups. Forty-two percent of the patients who received methylprednisolone and 33 percent of those who received placebo reported marked or very marked improvement (95 percent confidence interval for the difference, -11 to 28 percentage points; P = 0.53). The results were similar after three months. At the six-month evaluation, the patients treated with methylprednisolone reported more improvement, less pain on the visual-analogue scale, and less physical disability. The differences were reduced, however, when concurrent interventions were taken into account. Moreover, only 11 patients (22 percent) in the methylprednisolone group and 5 (10 percent) in the placebo group had sustained improvement from the first month to the sixth month (95 percent confidence interval for the difference, -2 to 26; P = 0.19). CONCLUSIONS. We conclude that injecting methylprednisolone acetate into the facet joints is of little value in the treatment of patients with chronic low back pain.     

The Comprehensive Muscular Activity Profile (CMAP): Its Clinical Utility in Objectively Differentiating Between Low Back Pain Patients and Normals1

Earlier findings demonstrated that the comprehensive muscular activity profile (CMAP) system was a powerful clinical method for evaluating lumbar range of motion (ROM) and lifting capacity (LC) while also documenting participant effort. A subsequent study also reported the CMAP's clinical utility for patients with musculoskeletal pain claims. Building upon these studies, the present investigation evaluated the CMAP's ability to reliably differentiate between healthy individuals versus those with low back pain (LBP). Twenty LBP patients and 20 demographically matched healthy subjects were administered the CMAP protocol (measuring ROM and LC). For ROM, there were no significant differences between the groups for overall performance and for degree of effort. However, for the LC, there were significant differences between groups: the LBP patients displayed lower performance relative to normals. Results demonstrate the clinical utility of the CMAP for the objective quantification of functional differences between the two groups.     

Learned maintenance of pain: muscle tension reduces central nervous system processing of painful stimulation in chronic and subchronic pain patients.

The effect of level of muscle tension on the perception of painful stimuli was assessed in 13 chronic back pain patients, 14 subjects at high risk for chronic back pain, and 14 matched healthy controls. Subjects received painful intracutaneous electric stimuli to the forearm or the lower back while they produced either high or low muscle tension levels. Visual analog scale (VAS) ratings of acute pain were obtained after each trial. Electroencephalograms, electromyograms, skin conductance levels, and blood pressure were measured during the trials. Although subjective pain ratings were not significantly affected by muscle tension levels, the chronic pain patients displayed elevated N150 and N150/P260 amplitudes of the somatosensory-evoked potentials in the low as compared to the high muscle tension condition. The high risk group showed a trend toward higher N150 amplitudes in the low as compared to the high tension condition. The results of this study partially support the hypothesis that increases in muscle tension might serve as a pain-reducing mechanism in chronic pain patients and those at risk for chronicity, thus leading to a vicious pain-tension cycle.     

A cognitive dual task affects gait variability in patients suffering from chronic low back pain

Chronic pain and gait variability in a dual-task situation are both associated with higher risk of falling. Executive functions regulate (dual-task) gait variability. A possible cause explaining why chronic pain increases risk of falling in an everyday dual-task situation might be that pain interferes with executive functions and results in a diminished dual-task capability with performance decrements on the secondary task. The main goal of this experiment was to evaluate the specific effects of a cognitive dual task on gait variability in chronic low back pain (CLBP) patients. Twelve healthy participants and twelve patients suffering from CLBP were included. The subjects were asked to perform a cognitive single task, a walking single task and a motor-cognitive dual task. Stride variability of trunk movements was calculated. A two-way ANOVA was performed to compare single-task walking with dual-task walking and the single cognitive task performance with the motor-cognitive dual-task performance. We did not find any differences in both of the single-task performances between groups. However, regarding single-task walking and dual-task walking, we observed an interaction effect indicating that low back pain patients show significantly higher gait variability in the dual-task condition as compared to controls. Our data suggest that chronic pain reduces motor-cognitive dual-task performance capability. We postulate that the detrimental effects are caused by central mechanisms where pain interferes with executive functions which, in turn, might contribute to increased risk of falling.     

Attentional Strategy Moderates Effects of Pain Catastrophizing on Symptom-Specific Physiological Responses in Chronic Low Back Pain Patients

In the present study, we examined whether experimentally-manipulated attentional strategies moderated relations between pain catastrophizing and symptom-specific physiological responses to a cold-pressor task among sixty-eight chronic low back patients. Patients completed measures of pain catastrophizing and depression, and were randomly assigned to sensory focus, distraction or suppression conditions during a cold pressor. Lumbar paraspinal and trapezius EMG, and cardiovascular responses to the cold pressor were assessed. Attentional strategies moderated the relation between pain catastrophizing and lumbar paraspinal muscle, but not trapezius muscle or cardiovascular responses. Only for participants in the suppression condition was catastrophizing related significantly to lumbar paraspinal muscle responses. Depressed affect did not account for this relation. These findings indicate that ‘symptom-specific’ responses among pain catastrophizers with chronic low back depend on how they attend to pain-related information. Specifically, it appears that efforts to suppress awareness of pain exaggerate muscular responses near the site of injury.     

Low back muscle fatigue during Sørensen endurance test in patients with chronic low back pain: relationship between electromyographic spectral compression and anthropometric characteristics

This study assessed low back muscle fatigue during S?rensen back endurance test in chronic low back pain (CLBP) patients and healthy controls, and investigated relationship between the erector spinae muscle fatigability and subject's anthropometric characteristics. Four groups (n = 10 per group) of middle-aged (47-52-year-old) subjects participated: 1) female CLBP patients, 2) healthy female subjects, 3) male CLBP patients and 4) healthy male subjects. Subjects performed S?rensen back endurance test until exhaustion, while electromyographic (EMG) power spectrum median frequency compression over time (MF slope) as indicator of the erector spinae muscle fatigability, and endurance time were recorded. The endurance time was shorter (p < 0.05) in male CLBP patients compared to the healthy male and female subjects. No significant gender differences in endurance time were found in CLBP patients and in healthy subjects. EMG power spectrum MF slope did not differ significantly in CLBP patients and in healthy subjects. However, MF slope was higher (p < 0.05) in healthy male than in female subjects. Body mass and BMI correlated moderately positively with MF slope (r = 0.40-0.67) in all measured groups. We conclude that male CLBP patients had lower back extensor muscle isometric endurance compared to the healthy subjects of both genders, whereas no gender differences in isometric endurance were found in CLBP patients and in healthy subjects. Healthy male subjects had greater lumbar erector spinae muscle fatigability compared to the healthy female subjects. Subjects with higher body mass and body mass index fatigued faster during S?rensen back endurance test.     

Recall Bias in Patients with Chronic Low Back Pain: Individual Pain Response Patterns Are More Important Than Pain Itself!

Background

Patients’ cognitive processing of pain-related information as well as their cognitive, affective and behavioral response pattern when experiencing pain in daily life has been shown to be associated with poorer prognosis in low back pain. However, the relationship between specific cognitive processes such as recall of pain-related material and individual pain responses remains unknown.

Purpose

The present study sought to investigate recall bias in patients with chronic low back pain (CLBP) compared to healthy controls. Furthermore, it was aimed to investigate the impact of patients’ individual pain-related responses on recall bias, comparing fear-avoidance response (FAR), endurance response (ER) and adaptive response (AR) patterns.

Method

Thirty-one CLBP patients and 31 controls were tested on a free recall task with three word lists comprising pain words and neutral words. Further, the CLBP group was classified into patients with a FAR, ER and AR pattern, using a short screening including the Avoidance-Endurance Questionnaire (AEQ). Group differences with pain status (CLBP vs. healthy) and AEQ responses (FAR, ER, AR) as between-group factors, word type (pain vs. neutral) as within-group factor and free recall as dependent variable were analysed by means of repeated-measures analysis of (co-) variance.

Results

Results revealed different pain processing of pain words between FAR and ER patterns, whereas CLBP patients as a whole did not differ from the healthy controls. FAR patients displayed significantly less recall than ER patients.

Conclusion

Recall biases in CLBP patients are not only a result of experiencing pain but also effected by patients’ pain response pattern with respect to fear-avoidance versus endurance.

     

Frequency of MMPI profile types in three chronic illness populations

Clinical interpretation of the MMPI most often utilizes configural or profile analysis. However, most MMPI research has focused only on single scale comparisons. In this study sorting rules to identify four common MMPI configurations were developed and applied to four S populations (N = 157): Chronic low back pain patients, migraine headache patients, hypertensives, and diabetics. No differences in frequencies of these profile types were found among the groups, although the chronic low back pain patients did have more elevated profiles. Variables of age, chronicity of illness and gender did not seem to influence profile type, while some differences were found between patients who rated themselves high and low in activity limitation due to the illness.     

Treatment of low back strain with electromyographic biofeedback and relaxation training

The authors examine the efficacy of electromyographic (EMG) biofeedback and relaxation training for chronic low back pain. Four case studies suggest that this combined treatment can lead to marked physical improvement, as evaluated by comprehensive neurologic examination. The patients under study experienced significant reduction in muscular tension in the paralumbar area as well as substantial pain relief. After treatment the patients were either working or seeking employment. The authors conclude that EMG biofeedback can be an effective treatment for intractable pain.     

The segmental dorsal ramus neuropathy as a common cause of chronic and recurrent low back pain.

The causes of recurrent and chronic low back pain usually remain unknown. The dorsal ramus lesion was found in 57 of 200 low back pain patients in this study in L5 or L4 segment without any neurophysiologic or neuroradiologic evidence of proximal ventral root compression. The neuropathy of dorsal rami, especially in their medial branches seems to be surprisingly common finding associated with low back pain and referred symptoms.     

核心力量训练干预老年慢性下腰疼的研究与进展

BACKGROUND: Numerous studies have confirmed the effectiveness of core strength training, most of which focus on the adult rather than the elderly.  OBJECTIVE: To review the relevant literatures targeting the elderly with low back pain and to explore the mechanism of core strength training in the treatment of elderly low back pain as well as different training methods and precautions, in order to provide theoretical basis for treatment of elderly patients with chronic low back pain. METHODS: Studies on the application of core strength training in the elderly with low back pain were retrospectively reviewed using bibliometrics method. The keywords were “chronic low back pain, core strength training, elderly person” in English and Chinese, respectively. RESULTS AND CONCLUSION: A large number of scholars have focused on the non-pathological therapy for elderly patients with chronic lower back pain. Core strength training for treatment of low back pain is characterized as a simple operation, low cost, significant effectiveness and few side effects, which is basically applicable in different groups. Combination of two or more exercise therapies can enhance the core strength training effect. In addition, correct health concept education, psychological and behavioral interventions are necessary to o eliminate the fear of pain and improve patient compliance, thereby increasing the effectiveness of exercise therapy. During the core strength training, we also should pay attention to distinguish the severity of diseases, degree of urgency, stage of disease, age, and individual physical differences, and take targeted exercises.        

Back pain in the elderly: A review

Low back pain is a common symptom in the older person. Whilst the majority of cases are thought to be mechanical or idiopathic and benign in nature, its multiple potential causes and concerns regarding missed diagnosis of less common but more serious underlying pathological diagnoses mean many physicians find the assessment, investigation and treatment of chronic low back pain in older adults challenging. This narrative review describes the classification of low back pain in older adults, discusses both mechanical and sinister causes of pain, highlights the appropriate use of medical imaging and provides an overview of surgical and non-surgical management of these patients.     

Predicting persistent disabling low back pain in general practice: a prospective cohort study

BACKGROUND: Patients may adopt active and/or passive coping strategies in response to pain. However, it is not known whether these strategies may also precede the onset of chronic symptoms and, if so, whether they are independent predictors of prognosis. AIM: To examine, in patients with low back pain in general practice, the prognostic value of active and passive coping styles, in the context of baseline levels of pain, disability and pain duration. DESIGN OF STUDY: Prospective cohort study. SETTING: Nine general practices in north west England. METHOD: Patients consulting their GP with a new episode of low back pain were recruited to the study. Information on coping styles, pain severity, disability, duration, and a brief history of other chronic pain symptoms was recorded using a self-completion postal questionnaire. Participants were then sent a follow-up questionnaire, 3 months after their initial consultation, to assess the occurrence of low back pain. The primary outcome was persistent disabling low back pain, that is, low back pain at 3-month follow-up self-rated as >or=20 mm on a 100 mm visual analogue scale, and >or=5 on the Roland and Morris Disability Questionnaire. RESULTS: A total of 974 patients took part in the baseline survey, of whom 922 (95%) completed a follow-up questionnaire; 363 individuals (39%) reported persistent disabling pain at follow-up. Persons who reported high levels of passive coping experienced a threefold increase in the risk of persistent disabling low back pain (relative risk [RR] = 3.0; 95% confidence interval [CI] = 2.3 to 4.0). In contrast, active coping was associated with neither an increase nor a decrease in the risk of a poor prognosis. After adjusting for baseline pain severity, disability, and other measures of pain and pain history, persons who reported a high passive coping score were still at 50% increased risk of a poor outcome (RR = 1.5; 95% CI = 1.1 to 2.0). CONCLUSION: Patients who report passive coping strategies experience a significant increase in the risk of persistent symptoms. Further, this risk persists after controlling for initial pain severity and disability. The identification of this low back pain subgroup may help target future treatments to those at greatest risk of a poor outcome.