Electromyographic recordings of low back pain subjects and non-pain controls in six different positions: effect of pain levels.

Surface electromyographic (EMG) activity recordings of bilateral paraspinal muscle tension were measured twice on 20 non-pain controls and on 46 low back pain subjects (21 individuals with intervertebral disk disorders and 25 subjects with unspecified musculoskeletal backache) during 6 positions: standing, bending from the waist, rising, sitting with back unsupported, sitting with back supported, and prone. Back pain subjects were measured during both low pain and high pain states. Results revealed a non-significant trend for all subjects, regardless of diagnosis, to have higher paraspinal muscle tension levels on the second (or high pain) assessment. A significant diagnosis by position interaction was observed which was similar to the interaction in our previous study which employed only a single measurement session. Analysis of simple main effects revealed this to be due to control subjects during the standing position having lower EMG levels than the back pain groups, and intervertebral disk disorder subjects having higher EMG levels than the other groups during the supported sitting position. As in our previous study, diagnosis was found to be a clinically significant factor, in that controls had much fewer clinically abnormal readings than back pain patients. The lack of a significant effect for pain state is congruent with findings in the headache literature. The importance of clearly defined diagnostic categories in low back pain research and the utility of measuring subjects in various positions is discussed, as are possible explanations for lack of significant pain state findings.     

American and Japanese chronic low back pain patients: cross-cultural similarities and differences

The study compared and contrasted medical, psychological, social and general behavioral functioning of American and Japanese low back pain patients and normal controls. The Sickness Impact Profile and a standardized Medical Examination Protocol for Pain instrument were used to assess all subjects. Findings showed that the American and Japanese low back pain patients had similar and significantly higher medical-physical findings than their respective controls. Likewise, the American and Japanese low back pain patients showed significantly greater psychological, social, and general behavioral dysfunction compared to control subjects. Finally, despite similar medical and physical findings, the Japanese low back pain patients were significantly less impaired in psychological, social, vocational, and avocational functioning than the American low back pain patients. It was concluded that there were significant cross-cultural differences between the American and Japanese low back pain patients, primarily in the psychosocial and behavioral areas. However, given the small sample size, any conclusion should be considered with caution; replication is needed before more definite conclusions are possible.     

Cross-validation of the Back Pain Classification Scale with chronic, intractable pain patients

The current study investigated the utility of the Back Pain Classification Scale with chronic, intractable low back pain and headache patients. Subjects consisted of 50 chronic low back pain and 50 chronic headache patients referred to a university based Pain Center for evaluation. Data indicated that subjects were a representative sample of severely intractable chronic pain patients typically referred for Pain Center evaluation and treatment. Each was administered the Back Pain Classification Scale as part of a thorough physical and psychological/behavioral evaluation. All subjects were classified by blind review of medical records into one of two categories: (1) presence of psychopathologically based pain complaint with little or no pathophysiological findings and (2) presence of pathophysiologically based pain complaints with little or no psychopathological findings. Subjects were also independently classified from blind review of their scores on the Back Pain Classification Scale into one of these two categories. Findings revealed that the Back Pain Classification Scale accurately predicted the actual classification of 80% of the low back pain patients (i.e., 30% above baseline prediction rate) and only 60% of the chronic headache patients (i.e., only equal to the baseline prediction rate). Furthermore, the scale was found to be most accurate in predicting low back pain patients with primary psychopathologically based pain. It was concluded that the Back Pain Classification Scale was an empirically valid instrument to use with chronic low back pain patients, but not with chronic headache patients. This lack of utility with chronic headache patients was also viewed as support for the construct validity of the scale. Wider use of the scale with chronic low back pain patients was suggested.     

Severity of low back pain. A comparison between participants who did and did not receive counseling.

Chronic low back pain is considered to be one of the most disabling and devastating conditions in working populations. The severity of chronic low back pain is associated with multicausal risk factors. Factors other than counseling have an effect on the severity of chronic low back pain. These factors need to be identified. Further research is needed to identify precise methods that affect the severity of chronic low back pain.     

Abdominal Muscle Endurance and its Association with Posture and Low Back Pain: An initial investigation in male and female élite gymnasts

Low back pain is a common consequence of gymnastic training. Potential aetiological factors include postural muscle weakness and abnormal posture. This study assessed the incidence of, and relationship between, reduced postural muscle endurance, posture type and low back pain in 12 male and 10 female élite gymnasts and matched controls. Postural muscle endurance was assessed using a pressure biofeedback unit (PBU). Posture was categorised subjectively by observation. History of low back pain was determined by questionnaire. Postural muscle endurance was non-significantly reduced (P > 0.05) in all gymnasts.The most common postures reported were sway-back (male gymnasts 100%; male controls 62.5%), lordosis (female gymnasts 80%) and normal (female controls 70%). Low back pain was reported in two female gymnasts, two female controls, nine male gymnasts and two male controls. Postural muscle endurance tended to reduce (P > 0.05) in those subjects with low back pain and lordotic postures. Low back pain was slightly more prevalent in those subjects with a sway-back posture. There is some evidence of a link between low back pain, posture and postural muscle endurance in gymnasts although no cause-and-effect relationships can be determined. These data should be further investigated and the practical implications for gymnasts and their training should be evaluated.     

Motion palpation findings and self-reported low back pain in a population-based study sample

BACKGROUND: Although the clinical usefulness of motion palpation has not been established, it is one of the most commonly used diagnostic methods by chiropractors. Notably, its sensitivity, specificity, and validity in general have not been adequately studied, and most study samples have consisted of student volunteers. OBJECTIVE: To determine the prevalence of positive motion-palpation findings (so-called fixations and spontaneous pain response) in relation to self-reported low back pain status and to determine the sensitivity and specificity of the motion-palpation technique carried out on the sacroiliac and lumbar joints. DESIGN: Study subjects were examined by 1 examiner (out of 7 possible), who was unaware of their low back pain status. Information on low back pain was then collected in a self-report questionnaire. SETTING: Research laboratory at the Odense University Hospital, Denmark. PARTICIPANTS: One hundred eighty-four twins, consisting of a subset of healthy twins taken from a panel of population-generated twins aged 19 to 42 years, made up the study sample. Examiners consisted of 7 biomechanics (chiropractic) students from the University of Southern Denmark who were proficient in motion palpation. MAIN OUTCOME MEASURES: The prevalence rates of motion palpation-determined fixations and of spontaneous pain reactions in response to motion palpation were studied in relation to anatomic area, self-reported low back pain status, and each other. RESULTS: The point period prevalence of low back pain was 14%. Fixations were found in 43% of the study sample, and 25% appeared to have a painful reaction to motion palpation. There was no logical pattern of fixations and spontaneous pain reactions in relation to the low back pain status. The sensitivity was generally low (always below 60%) for fixations and pain, whereas the specificity was higher, significantly so for pain in the mid lumbar area. There was no strong association between fixations and the examiners' interpretation of a spontaneous pain reaction in response to motion palpation. CONCLUSION: Motion palpation does not appear to be a good method to differentiate persons with or without low back pain. It is possible to dissociate the findings of fixations and those of pain reactions.     

Chronic low back pain patients around the world: cross-cultural similarities and differences.

OBJECTIVE: The current study sought to determine whether there were any significant cross-cultural differences in medical-physical findings, or in psychosocial, behavioral, vocational, and avocational functioning, for chronic low back pain patients. DESIGN: Partially double-blind controlled comparison of six different culture groups. SETTING: Subjects were selected from primarily ambulatory care facilities specializing in treating chronic pain patients. PATIENTS-SUBJECTS: Subjects consisted of 63 chronic low back pain patients and 63 healthy controls. Low back pain patients were randomly selected from six different culture groups (American, Japanese, Mexican, Colombian, Italian, and New Zealander). Ten to 11 were gathered per culture from a pool of patients treated at various pain treatment programs. Likewise, 10 or 11 control group subjects were obtained from each culture from a pool of healthy support staff. MAIN OUTCOME MEASURES: The Sickness Impact Profile and the Medical Examination and Diagnostic Information Coding System were used as primary outcome measures. RESULTS: Findings showed that (a) low back pain subjects across all cultures had significantly more medical-physical findings and more impairment on psychosocial, behavioral, vocational, and avocational measures than controls did; (b) Mexican and New Zealander low back pain subjects had significantly fewer physical findings than other low back pain groups did; (c) the American, New Zealander, and Italian low back pain patients reported significantly more impairment in psychosocial, recreational, and/or work areas, with the Americans the most dysfunctional; and (d) findings were not a function of working class, age, sex, pain intensity, pain duration, previous surgeries, or differences in medical-physical findings. CONCLUSIONS: It was concluded that there were important cross-cultural differences in chronic low back pain patients' self-perceived level of dysfunction, with the American patients clearly the most dysfunctional. Possible explanations included cross-cultural differences in social expectation; attention; legal-administrative requirements; financial gains; attitudes-expectations about usage, type, and availability of health care; and self-perceived ability and willingness to cope.     

A comparison of pressure pain detection thresholds in people with chronic low back pain and volunteers without pain

BACKGROUND AND PURPOSE: Palpation is often utilized in the physical examination of patients with low back pain. The purpose of this study was to compare the pressure pain detection threshold (PPDT) of people with chronic low back pain (CLBP) and subjects without pain. SUBJECTS AND METHODS: Thirty female subjects with CLBP were recruited from the offices of primary care physicians and physical therapists and compared with 30 female volunteers without pain for differences in PPDT at 6 sites tested bilaterally. RESULTS: A significantly lower mean PPDT was found for all test site groups in subjects with CLBP compared with subjects without pain. A lower global PPDT was found in subjects with CLBP compared with subjects without pain (5.6 lb/cm(2) versus 6.9 lb/cm2). This also was the case for PPDT for the group of test sites unrelated to the lumbar spine (5.1 lb/cm(2) versus 6.1 lb/cm(2)) and for PPDT related to the lumbar spine (5.9 lb/cm(2) versus 8.0 lb/cm(2)). DISCUSSION AND CONCLUSION: Neurobiological or biopsychosocial influences may have contributed to the lower PPDT evident in subjects with CLBP. Subjects with CLBP demonstrated a lower global PPDT compared with subjects without pain, which should be taken into account when interpreting findings of pain or tenderness from palpation.     

Psychosocial Differences Between High-Risk Acute vs. Chronic Low Back Pain Patients

▪ Abstract:   The present study was designed to evaluate the relative degree and type of emotional distress in high-risk acute low back pain (ALBP) subjects (defined as less than 3 months since initial injury) vs. high-risk chronic low back pain (CLBP) subjects (defined as greater than 3 months since initial injury). It is an extension of earlier findings that demonstrated the significant role that such emotional distress may play in the development of CLBP disability if not appropriately treated in the acute phase. This work stems from a conceptual three-stage model, which characterizes the progression from acute to chronic pain. Several psychosocial measures were administered that included information allowing for the classification of subjects as high-risk based upon an earlier developed screening algorithm. The ancova procedure in SPSS was used to compare groups, controlling for gender, ethnicity, and age. Results revealed that CLBP subjects had higher rates of certain measures of emotional distress and depression relative to ALBP subjects. These findings further support the importance of effectively managing emotional distress factors early, when treating musculoskeletal disorders such as low back pain. ▪     

Lumbar percutaneous KTP532 wavelength laser disc decompression and disc ablation in the management of discogenic pain

The objective of this research was to determine the outcome of laser disc decompression and laser disc ablation in the management of painful degenerative disc disease with or without associated disc prolapse. Nonendoscopic percutaneous laser disc decompression was performed under x-ray control via the posterolateral approach with side-firing probes. All patients with chronic back pain who had reproduced pain during discography of a nature, pattern, and distribution similar to what they experienced normally were included in the study. Magnetic resonance which confirmed stenosis and sequestrated discs, and patients with acute neurological findings were excluded from the study. Laser disc decompression or ablation was done using the KTP532 wavelength. The functional outcome was assessed prospectively using the Oswestry Disability Index. Clinical benefit was considered significant in those patients with a percentage change in the index of > or =50% at review 3-9 years (mean, 5.33 years) following surgery. A total of 52% of patients demonstrated a sustained significant clinical benefit, with an additional 21% in whom functional improvement was noted. Cohort integrity was 67%. Long-term benefit of the laser disc ablation and decompression for discogenic pain suggests a mechanism other than principally mechanical as a cause of chronic back and sciatic pain. It may suggest that efficacy occurs by reduction in the intradiscal production of irritative products and by an effect upon discal and annular neoneuralization. The sustained nature of the benefit after long-term preoperative symptoms (mean, 4.7 years) rules out any placebo effect. Selection should be restricted to patients without significant lateral recess stenosis, retrolisthesis or olisthesis of > or =3 mm, significant dorsal or foraminal osteophytosis, extrusion, or sequestration.     

Biopsychosocial factors are associated with low back pain in female nursing students: A cross-sectional study

Background

Occupational low back pain is a significant problem among nurses. Recent literature suggests current occupational preventative strategies for nurses have not been effective. Given low back pain is already prevalent before commencing employment, nursing students should be the target of preventative interventions. Modifiable personal factors which contribute to low back pain have proven difficult to identify, but are thought to play an important role in the biopsychosocial nature of low back pain.

Objectives

To evaluate the contribution of personal biopsychosocial factors to low back pain in nursing students.

Design

Cross-sectional study comprising physical testing and questionnaires.

Settings

Two university undergraduate nursing schools in Western Australia.

Participants

170 female undergraduate nursing students.

Methods

Low back pain and control subjects were compared across social, lifestyle (physical activity), psychological (stress, anxiety, depression, back pain beliefs, coping strategies and catastrophising) and physical (spinal postures and spinal kinematics in functional tasks, leg and back muscle endurance, spinal repositioning error and cardiovascular fitness) characteristics. Low back pain was considered as either “minor” or “significant” depending upon pain severity, duration, impact and level of disability.

Results

Over 30% of all subjects (mean age 22.5 ± 4.5 years) reported “significant” low back pain in the preceding 12 months. Univariate analysis: social measures did not distinguish between groups. Subjects with “significant” low back pain were more physically active (p = 0.04), had higher stress scores (p = 0.01) and used passive coping strategies (p < 0.001) more than other subjects. “Significant” low back pain subjects held their lower lumbar spine in a more extended posture during transfers at bed height than other subjects. No differences between groups were found for sagittal spinal mobility, static spinal posture, muscle endurance, spinal repositioning error, cardiovascular fitness or other psychological measures. Multivariate analysis: regression analysis revealed stress, coping, physical activity, spinal kinematics, and age all contributed independently to the presence of low back pain, representing a significant 23% of variance.

Conclusions

Modifiable lifestyle, psychological and physical factors were independently associated with low back pain in nursing students. Targeting personal factors associated with low back pain in nursing students, rather than occupational factors in working nurses may help improve the impact of low back pain in nurses. Prospective studies are required to confirm the relevance of these findings for risk of future low back pain in nurses.     

Correlation of Body Composition and Low Back Pain Severity in a Cross-Section of US Veterans

Objective

Back pain is more prevalent in the obese, but whether back pain severity is directly correlated to obesity in veterans is unknown. We sought to determine if there was a correlation between body composition and low back pain severity in a sample of veterans. The hypothesis was that veterans with higher body mass index values would report higher low back pain severity scores.

Isometric back strength of low back pain patients and healthy controls.

The primary objective of this study was to determine the back strength of low back pain patients and to compare their values with healthy control subjects. Using the back and leg dynamometer, we measured the isometric back strength of 21 patients (14 men and 7 women), with chronic low back pain and 21 (14 men and 7 women) healthy (control) subjects. Both groups are comparable (p greater than 0.05) in age, body weight, height and Quetelet index (weight/height2). The back strength of the low back pain patients is not significantly (p greater than 0.05) different from their sex, age and anthropometric matched healthy controls. However, the males in the study were stronger (p less than 0.01) than their female counterparts. Based on our findings, we conclude that weakness of the paraspinal extension muscles is not the likely primary cause of idiopathic low back pain.     

Graded back pain revisited – Do latent variable models change our understanding of severe back pain in the general population?

Back pain severity has extensively been targeted in clinical and epidemiologic studies. However, despite the importance of a valid pain severity grading its adequate conceptualization in the general population has received comparatively little attention. The potentially misleading influence of measurement error remains unclear. Latent variable models allow for a versatile assessment of disease severity and will be applied to propose a model-based grading of back pain. This cross-sectional postal survey was carried out in Germany between 2003 and 2004 to address back pain severity in the general adult population. 8756 subjects, aged 18–75 years, provided data on measures of pain intensity and disability. Latent class analysis and confirmatory factor analysis were used to assess and compare categorical and dimensional representations of back pain severity. The results show that beyond differences in their location on a severity continuum, the subjects did not report markedly different pain intensity/disability profiles. Our analyses disconfirmed the presence of a sizeable high pain intensity, low disability subgroup. A comparison of the different latent variable models yielded a usable classification into five severity subtypes. This classification showed statistically significant and clinically important associations to health-related variables. Our results confirm the high burden of back pain in the general population but suggest a different categorization of those with severe back pain. This entails consequences on how to best target this important health problem from a public health perspective.     

The assessment of radiating low back pain by thermal sensory testing

Low back pain radiating into the legs is a common pain syndrome. However, neurological examination, imaging and electromyographic studies are of limited value for prognosis or therapy. The origin of the pain remains unknown. The aim was to evaluate the potential of thermal sensory testing to serve as a diagnostic tool in 24 patients who had low back pain radiating down the S1 dermatome, compared with 26 pain-free controls. The method of limits was used to detect the thresholds of warm sensation, cold sensation, warm pain and cold pain at the L4, L5 and S1 dermatomes of the symptomatic and the non-symptomatic legs. Thresholds on the asymptomatic leg were similar to values obtained in controls. We found a significantly higher threshold for cold sensation in the S1 dermatome of the symptomatic leg of the patients compared with the controls (p< 0.005). In addition, patients who had abnormal neurological examination (50%) had higher thresholds for cold sensation or cold pain in the three dermatomes tested at the symptomatic leg compared with the non-symptomatic leg. No differences in the thresholds of warm sensation or warm pain were detected. We propose that these findings indicate selective damage to the Adelta fibres which are involved in transmission of cold sensation and pain, presumably by root compression. We found no evidence of involvement of C fibres, which transmit warm sensation and pain. Thermal testing should be considered among the testing modalities that are capable of demonstrating objective findings in patients with radiating low back pain.     

Lumbar motion trends and correlation with low back pain. Part II. A roentgenological evaluation of quantitative segmental motion in lateral bending.

OBJECTIVE: A radiographic study was undertaken to describe the relationship between the magnitude of coupled lumbar motion in lateral bending and the presence of low back pain: correlation between pain and motion, relationship between motion category and motion and symmetry of lumbar motion. DESIGN: Survey. SETTING: Chiropractic college student health center and private chiropractic clinic. PARTICIPANTS: 249 subjects: 114 with low back pain, 29 asymptomatic with no history and 106 asymptomatic with history. Of these, 194 were freshman volunteers and 55 were new private clinic low back pain patients. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Net lumbar segmental tilt and rotation in lateral bending: corrected and uncorrected for segmental malposition with the patient standing in the upright neutral position. RESULTS: Statistical analysis demonstrated no significant relationship between coupled lumbar motion and low back pain (p greater than .01). The presence of type II motion could account for, on average, less than 5% loss of segmental tilt in the lumbar spine. Asymmetries between left and right side motion averaged 45 to 100% of unilateral range of motion. CONCLUSIONS: This study suggests that back pain is not an indication for the routine use of lateral bending films for the identification of alterations in the magnitude of lumbar segmental motion in lateral bending. It further indicates that type II motion cannot be ruled out as a normal variant. The paucity of symmetrical lumbar motion suggests that segmental tilt or coupled rotation asymmetry, in and of itself, should not be considered an indication for spinal manipulation.     

Modelling the prevalence and cost of back pain with neuropathic components in the general population

Background: Although there is increasing knowledge of the prevalence of neuropathic pain, little has been done to isolate the cost of neuropathic pain, especially with reference to the frequent complaint of back pain. Aims: To estimate the prevalence of neuropathic components in back pain and associated costs. Methods: We used available epidemiological data to model the prevalence of neuropathic back pain in the general adult population, combining three studies: painDETECT 1, painDETECT 2, and the German back pain research network (GBPRN) study, representing a total of 21,047 subjects. The painDETECT screening questionnaire was used in the former two surveys to assess neuropathic pain components. Costing data were obtained from 1718 participants in the GBPRN survey. Results: According to our model, approximately 4% of the general adult population experienced back pain with a neuropathic component. Owing to the greater severity of neuropathic pain, its costs were found to be disproportionately high: among patients with persistent back pain, typical costs associated with a person suffering neuropathic back pain were higher than those of an average back pain patient, and as much as 67% higher than those of a patient with nociceptive back pain only. Approximately, 16% of the total costs associated with back pain were attributable to pain with a neuropathic component. Conclusions: Back pain with neuropathic components is likely to affect a relevant proportion of the general adult population and cause a disproportionately high share of back pain‐related costs.     

Disabling low back Oregon Workers' Compensation claims. Part II: Time loss.

This paper reports on time loss incurred by chiropractic (DC) and medical (MD) claimants with disabling low back work-related injuries in Oregon. Clinical categorization was accomplished using medical records and was based on reported symptomatology, objective clinical findings and functional impairment. The median time loss days for cases with comparable clinical presentation (severity) was 9.0 for DC cases and 11.5 for MD cases. Chiropractic claimants had a higher frequency of return to work with 1 wk or less of time loss. No difference was seen in time loss days for MD or DC claimants with no documented history of low back pain. However, for claimants with a history of chronic low back problems, the median time loss days for MD cases was 34.5 days, compared to 9 days for DC cases. It is suggested that chiropractors are better able to manage injured workers with a history of chronic low back problems and to return them more quickly to productive employment.