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PubMed1998

Classification of low back pain with the use of spectral electromyogram parameters.

STUDY DESIGN: An electromyogram procedure using spectral parameters to distinguish subjects with low back pain from those without. OBJECTIVES: To add to the growing database on this procedure, to assess the possible overfitting of data in the classification model, to determine whether a model based on a contraction level of 60% of maximum voluntary contraction can produce concordance rates similar to those in models based on 40% and 80% of maximum voluntary contraction, and to develop a classification model to distinguish subjects with low back pain from those without. SUMMARY OF BACKGROUND DATA: Other investigators have published a series of models in which spectral parameters measured during fatiguing contractions from the paraspinal muscles have been able to classify a subject into a low back pain or non-low back pain group with a more than 80% concordance rate. METHODS: Subjects with chronic low back pain (N = 21) and without (N = 18) performed a series of isometric, fatiguing back extensor contractions in which the median power frequency was measured bilaterally from T9, L3, and L5. A Student's t test was used to determine which parameters would be entered into the classification models. Discriminant analysis and logistic regression procedures were used to develop models to classify subjects and were compared for overfitting of data based on the number of input parameters. The logistic regression method used a holdout group (N = 6) for validation. RESULTS: The discriminant analysis selected all 10 input parameters and was believed to overfit the data. Logistic regression selected two parameters and had a concordance rate of 92.4%. Five of the six subjects in the holdout group were correctly classified. CONCLUSIONS: The use of spectral parameters to classify subjects with low back pain from those without appears to have merit. Compared with discriminant analysis, logistic regression provided an equally powerful method for classifying these two groups but did not overfit the data. Models based on 60% of maximum voluntary contraction demonstrated results comparable with those of previous research using 40% and 80% of maximum voluntary contraction.

Adult↗
PubMed1998

Increase in sick leave rates caused by back pain among pregnant Swedish women after amelioration of social benefits. A paradox.

STUDY DESIGN: A retrospective population study. OBJECTIVES: To explore whether the increase in social benefits for pregnant women introduced in Sweden between 1978 and in 1986 was associated with a decrease in the use of sick leave caused by back pain during the same period. SUMMARY OF BACKGROUND DATA: Back pain is a common condition among Swedish pregnant women. It may be regarded as a normal discomfort of pregnancy, because at least 50% of pregnant women experience back pain to some extent during pregnancy. METHODS: Participants were women consecutively delivered in 1978 (n = 1524) and in 1986 (n = 1688). Between these two time points, the number of offered days of parental benefit increased and a new benefit, the pregnancy benefit, was introduced. Data were collected from the antenatal care and delivery records and from pregnant women's social insurance files. RESULTS: From 1978 to 1986 the use of sick leave because of back pain during pregnancy increased. The number of pregnant women granted sick leave employed pregnant women because of back pain increased from 11% in 1978 to 29% in 1986 (P < 0.001). The sick leave rate increased in most occupations and especially among young women. CONCLUSIONS: The Swedish society has provided ample social benefits to allow the pregnant woman to take leave from work, without having to be labeled as "ill," because of normal conditions such as back pain during pregnancy. Instead of an expected decrease in sick leave because of back pain during pregnancy, an increase was observed.

Absenteeism↗
PubMed1998

A report from the Second International Forum for Primary Care Research on Low Back Pain. Reexamining priorities.

STUDY DESIGN: Consensus process. OBJECTIVES: Reexamining and redirecting the research agenda for low back pain in primary care. SUMMARY OF BACKGROUND DATA: Most research, publications, and funding have traditionally been directed toward specialty and biologically oriented investigations of "spinal disorders" from biomedical and biomechanical perspectives. Beginning in the mid-1980s, primary care researchers began to investigate this field in earnest, focusing on lower back pain as a pain syndrome within an individual, family, and community context. Unfortunately, more progress has been made on what should not be done in diagnosing and treating lower back pain than on what should be done. METHODS: This was a modified group process designed to reach consensus among an international group of primary care lower back pain researchers. RESULTS: Nearly all of the research priorities from the initial 1995 forum are still thought to be important, although only modest progress has been made on most of them. The priorities perceived to be the most feasible to investigate and the ones in which the greatest strides have been achieved are in methodologic rather than substantive areas. Identifying subgroups of people with lower back pain is still given top ranking in 1997, but the priorities have changed dramatically. Greater emphasis is given to finding predictors and risk factors for lower back pain chronicity, improving self-care strategies, and stimulating self-reliance. New items now make up 50% of the top 10 priorities. In general, the additions reflect a greater emphasis on expanding methodologic avenues of inquiry. CONCLUSIONS: Methodologic advances, the enlistment of new techniques and disciplines, and redirected research efforts may facilitate progress in the diagnosis and treatment of lower back pain.

Group Processes↗
PubMed1998

Work incapacity from low back pain in the general population.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To describe the incidence and duration of low back pain in patients from the general working population in Norway who take at least 2 weeks of compensated absence from work. SUMMARY OF BACKGROUND DATA: There is a growing concern about the proportion and socioeconomic consequences of work absence resulting from low back pain, and exact figures on incidence and duration of work incapacity from low back pain in the general working population are needed. METHODS: Cases were identified from files of the national medical insurance system, covering 90% of all employees in Norway. A total of 89,190 patients with low back pain were identified in 1995 and 1996, based on the International Classification of Primary Care (ICPC codes L02, L03, L84 and L86). Census data were used for the denominators. RESULTS: The estimated overall 1-year incidence was 2.27%. It was significantly higher for women (2.72%) than for men (1.91%). The incidence increased with increasing age. The median (25th-75th percentile) duration of absence for all claimants was 43 days (25th-75th percentile, 23-103). Approximately 35% of claimants returned to work after 1 month, 70% had returned after 3 months, and 85% had returned after 6 months. Thirty percent of all claimants had low back pain with radiation, and the median duration of absence for these was 59 days (25th-75th percentile, 28-152 days) versus 38 days (25th-75th percentile, 21-86 days) for claimants without radiating pain (P < 0.001). CONCLUSION: The results of this study reaffirm the burden of low back pain to society. The data show that the prognosis for the majority of this group of patients with low back pain, even for those with radiating symptoms, is generally good. From 6 to 20 weeks after onset, however, the return-to-work curve declined steeply among the individuals studied. Approximately 42% of those still off work after 6 months had not returned to work after 12 months, and were switched to permanent disability pension or other compensation forms.

Adolescent↗
PubMed1998

Range of motion and motion patterns in patients with low back pain before and after rehabilitation.

STUDY DESIGN: Data were collected from 27 patients who were participating in a rehabilitation program for chronic low back pain. The patients were tested on day 2 and day 11 of a 2-week rehabilitation program. OBJECTIVES: To determine specific characteristics of trunk motion associated with long-term dysfunction caused by low back pain of various origin, to determine if a neural network analysis system can be effective in distinguishing between patterns, and to determine if the rehabilitation has an effect on range and pattern of motion. SUMMARY OF BACKGROUND DATA: There is a lack of objective measures for evaluating the efficacy of rehabilitation programs. Numerous studies have established the difficulty of evaluating low back pain. Existing techniques, such as imaging methods, are in many cases either very rough and inaccurate or expensive and ineffective. A technique for evaluation of motion patterns in low back pain was developed based on analysis of dynamic motion features such as shape, velocity, and symmetry of movements. METHODS: Dynamic motion data were collected before and after rehabilitation from 27 patients with low back pain by using a triaxial goniometer. Range of motion and features of the movement, such as shape, velocity, and repetitiveness, were extracted for analysis. RESULTS: Motion features showed significant improvement after the rehabilitation program. CONCLUSIONS: A neural network based on kinematic data is an excellent model for classification of low back pain dysfunction. Such a system could markedly improve the management of low back pain for an individual patient.

Adult↗
PubMed1999

INTERMED--an assessment and classification system for case complexity. Results in patients with low back pain.

STUDY DESIGN: Cross-sectional investigation and follow-up of patients with low back pain. OBJECTIVES: To evaluate the capacity of the INTERMED--a biopsychosocial assessment and classification system for case complexity--to identify patients with a chronic, disabling course of low back pain and to predict treatment outcome. SUMMARY OF BACKGROUND DATA: An impressive number of biologic and nonbiologic factors influencing the course of low back pain have been identified. However, the lack of a concise, comprehensive, reliable and validated classification system of this heterogeneous patient population hampers preventive and therapeutic progress. METHODS: The INTERMED was used to assess patients with low back pain, who participated in a functional rehabilitation program (n = 50) and patients with low back pain who applied for disability compensation (n = 50). Patients of the rehabilitation program were observed to assess the effects of treatments. RESULTS: The INTERMED distinguished between patients in different phases of disability and provided meaningful information about the biopsychosocial aspects of low back pain. In hierarchical cluster analysis two distinct clusters emerged that differed in the degree of case complexity and treatment outcomes. CONCLUSIONS: This first application of the INTERMED indicates its potential utility as a classification system for patients with low back pain.

Adult↗
PubMed1999

Improving the evaluation of benign low back pain.

STUDY DESIGN: A prospective, blind study was conducted to investigate the factors underlying the decisions of expert clinicians in diagnosis of acute, benign low back pain, compared with results obtained with an automated physical examination by machine. From the results, a strategy to significantly improve clinical diagnosis in cases of discordance was determined. OBJECTIVES: To identify factors in the clinical assessment of low back pain that indicate when independent diagnostic testing would be useful. SUMMARY OF BACKGROUND DATA: The clinical evaluation of low back pain is often dominated by subjective reports of pain. Published medical literature has underscored several inherent weaknesses of the clinical examination, and concerns have been raised about its effectiveness for assessing patients with low back pain. Thus, it has been proposed that objective measures to complement the clinician's examination would be beneficial in the formulation of dependable diagnoses. METHODS: Randomly designated subjects, who in describing their conditions were objective or role playing, were assessed by clinicians and a machine for diagnosis of low back pain assessment versus normal backs. Each subject's pain assessment was compared with a gold standard that was established by experts in low back pain. Components of the clinical examination were analyzed to assess which were the most informative in making a reliable diagnosis. The information content of the machine assessment was also analyzed and a strategy to complement the clinical diagnosis with the machine diagnosis determined. RESULTS: Discordance among the various components of the clinical examination was a strong indicator of when the efficacy of the clinical examination dropped below a random level of decision making. When there was discordance, incorporating the functional evaluation by machine into the clinical diagnosis improved the performance of the clinician. Notably, in nonobjective subjects, the accuracy of diagnosis was enhanced by as much as 69%. CONCLUSIONS: It is possible to improve the accuracy of clinical diagnosis by incorporating a functional evaluation by machine when there is discordance between physical examination findings and reported pain.

Acute Disease↗
PubMed1999

The efficacy of active rehabilitation in chronic low back pain. Effect on pain intensity, self-experienced disability, and lumbar fatigability.

STUDY DESIGN: A randomized study comparing the results of active rehabilitation and passive control treatment in patients with chronic low back pain with follow-up at 6 months and 1 year. OBJECTIVES: To study the efficacy of active rehabilitation on pain, self-experienced disability, and lumbar fatigability. SUMMARY OF BACKGROUND DATA: Exercises in an outpatient setting are widely used for the treatment of chronic low back pain. The efficacy of the active rehabilitation approach has been documented in randomized control studies, but these studies have seldom been focused on lumbar fatigability, which is now recognized as a frequent problem among patients with chronic low back pain. METHODS: Fifty-nine middle-aged patients (37 men and 22 women) with nonspecific chronic low back pain were randomly assigned to 12 weeks' active rehabilitation or to a passive control treatment (massage, thermal therapy). Pain and disability index, low back pain intensity (visual analog scale, 100 mm), and the objectively assessed lumbar muscle fatigability (spectral electromyogram, mean power frequency slope [MPFSLOPE]) in a new 90-second submaximal isoinertial back endurance test were recorded before and after the interventions and at 6-month and 1-year follow-up visits. RESULTS: Results of repeated measures multivariate analysis of variance indicated that back pain intensity (visual analog scale) and functional disability (pain and disability index score) decreased, and lumbar endurance (MPFSLOPE) improved significantly more (P < 0.05) in the active rehabilitation group than in the passive control treatment group, when measured at a 1-year follow-up examination. The group difference in visual analog scale and pain and disability index changes became even more significant at the end of 1 year. The change in lumbar endurance was significantly greater in the active rehabilitation group than in the passive control treatment group at the 6-month follow-up, but not at the 1-year follow-up. CONCLUSIONS: The active progressive treatment program was more successful in reducing pain and self-experienced disability and also in improving lumbar endurance than was the passive control treatment. However, the group difference in lumbar endurance tended to diminish at the 1-year follow-up.

Adult↗
PubMed2000

The rates of false-positive lumbar discography in select patients without low back symptoms.

STUDY DESIGN: Experimental disc injections in subjects with no history of low back symptoms. OBJECTIVE: To determine in an experimental setting the relative pain response and pain-related behavior in selected subjects without a history of low back pain undergoing lumbar discography. This study aimed to select a study population that more closely represented patients undergoing discography in clinical practice. SUMMARY OF BACKGROUND DATA: Previous work has shown that in young, healthy men with little degenerative disc disease and no history of low back problems, discographic injections usually did not cause significant pain. This group differed from the patients who usually undergo discographic evaluation in clinical practice. Most clinical patients are older, have significant degenerative disc disease, have behavioral changes associated with chronic pain, and often have confounding psychosocial troubles. The authors undertook to study discography in subjects without low back pain but with clinical profiles similar to patients undergoing discography in clinical practice. METHODS: Twenty-six individuals, mean age 43 years, with no history of low back pain had lumber discography according to the strict protocol of Walsh et al. Of these, 10 were pain-free; 10 had chronic neck and arm pain, but no low back symptoms; and 6 had primary somatization disorders without low back symptoms.- RESULTS: Significant positive pain response and pain-related behavior with discography were found in 10% of the pain-free group, in 40% of the chronic cervical pain group, and in 83% of the somatization disorder group completing the injections. Twenty-four subjects had negative control discs. Discs with annular disruption were more likely to be painful on injection, particularly in those individuals with ongoing compensation issues, chronic pain, or abnormal psychological testing.- CONCLUSION: If strict criteria are applied, the rate of false-positive discography may be low in subjects with normal psychometric profiles and without chronic pain. Significantly painful injections were very common in subjects with annular disruption and chronic pain or abnormal psychometric testing.

Adult↗
PubMed2000

Treatment of acute low back pain with the COX-2-selective anti-inflammatory drug nimesulide: results of a randomized, double-blind comparative trial versus ibuprofen.

STUDY DESIGN: A prospective, randomized double-blind comparative trial. OBJECTIVES: To evaluate the efficacy and tolerability of nimesulide, a cyclooxygenase (COX)-2-selective anti-inflammatory agent versus ibuprofen in patients with acute lumbosacral back pain. SUMMARY OF BACKGROUND DATA: Nonsteroidal anti-inflammatory drugs (NSAIDs) have been more effective than placebo in patients with uncomplicated acute low back pain in previous randomized controlled trials. The efficacy and tolerability of a new COX-2-selective anti-inflammatory drug have not yet been established. METHODS: One hundred four patients aged 18-65 years with acute low back pain were enrolled. The patients were randomly allocated either to oral nimesulide (100 mg twice daily for 10 days) or oral ibuprofen (600 mg three times daily for 10 days). Outcome measures on a visual analog scale were an average of the pain intensity and the pain relief, stiffness in the back, functional status, and the results of physical examinations. All side effects were recorded at each visit. RESULTS: With both study therapies, there was a clear improvement in all measured parameters of the pain and back function parameters measured from the third day of treatment onward. The patients' capacity for daily tasks, showed improvement in both groups (P < 0. 001), but a statistically significant difference was found between the two groups in favor of the nimesulide group (P < 0.05) after 10 days. Nimesulide was more effective than ibuprofen in improved lateral bending measurements (P = 0.026). Nimesulide and ibuprofen provided similar degrees of improvement in the modified Schober tests and in the pain intensity and back stiffness scores. More gastrointestinal side effects were reported with ibuprofen than nimesulide, and the comparison showed a trend (P = 0.067). Ten side effects occurred in the nimesulide group in 7 (13%) patients and 13 in the ibuprofen group in 11 (21%) patients. CONCLUSIONS: The results confirmed that the COX-2-selective inhibitor nimesulide is an effective and well-tolerated agent for use in general practices to treat acute low back pain. The incidence of gastrointestinal side effects seems to be lower with nimesulide than with ibuprofen.

Acute Disease↗
PubMed2000

Exploration of physicians' recommendations for activities in chronic low back pain.

STUDY DESIGN: A mailed survey of 142 practicing physicians (63 orthopedic spine surgeons and 79 family physicians) inquiring about their expertise and experience with chronic low back pain, their pain attitudes and beliefs, and recommendations about the appropriate level of function for chronic back pain patients. OBJECTIVES: To explore physicians' recommendations for activity and work for patients with chronic low back pain and to determine factors that might influence these recommendations. SUMMARY OF BACKGROUND DATA: Physicians continuously are asked to recommend the appropriate level of activities and work for patients with chronic low back pain. Although these recommendations can have a significant impact on patients' lives, little is known about the factors that shape recommendations. METHODS: Mailed surveys included questions inquiring about the physicians' demographics, training, and experience in low back pain, the Health Care Providers' Pain and Impairment Relationship Scale, and three vignettes of work-disabled, chronic low back pain patients. After each vignette, physicians rated their perceptions of severity of symptoms and pathology and recommendations for work and daily activities through five graded responses. Three mailings were done within 4 weeks to maximize the response rate. The association of each variable with work and activity recommendations was statistically explored. To assess the influence of clinical expertise on recommendations, the responses of orthopedic spine surgeons were compared with those of family physicians. Test-retest reliability was assessed with a second mailing of the questionnaire to all initial responders. RESULTS: Sixty-five percent of the orthopedic surgeons and 52% of the family physicians responded to the survey. Thirty-nine percent of the initial responders completed the reliability survey. The survey instrument demonstrated modest reliability, with identical recommendations for activities and work occurring 57% of the time. In general, a wide range of activities and work was recommended, with most physicians recommending avoidance of painful activities or greater restrictions. Orthopedic spine surgeons were slightly less restrictive in their activity recommendations compared with family physicians. Most physicians demonstrated some consistency in their pattern of recommendations when compared with their colleagues. Physicians' pain attitudes and belief influenced their recommendations, as did their perception of the severity of the patients' clinical symptoms. CONCLUSIONS: Physicians' recommendations for activity and work to patients with chronic back pain vary widely and frequently are restrictive. These recommendations reflect personal attitudes of the physicians as well as factors related to the patients' clinical symptoms.

Activities of Daily Living↗
PubMed2000

Flexion and rotation of the trunk and lifting at work are risk factors for low back pain: results of a prospective cohort study.

STUDY DESIGN: A 3-year prospective cohort study among workers of 34 companies in the Netherlands. OBJECTIVES: To investigate the relation between flexion and rotation of the trunk and lifting at work and the occurrence of low back pain. SUMMARY OF BACKGROUND DATA: Previous studies on work-related physical risk factors for low back pain either lacked quantification of the physical load or did not take confounding by individual and psychosocial factors into account. METHODS: The study population consisted of 861 workers with no low back pain at baseline and complete data on the occurrence of low back pain during the 3-year follow-up period. Physical load at work was assessed by means of analyses of video-recordings. Information on other risk factors and the occurrence of low back pain was obtained by means of self-administered questionnaires. RESULTS: An increased risk of low back pain was observed for workers who worked with the trunk in a minimum of 60 degrees of flexion for more than 5% of the working time (RR 1.5, 95% CI 1.0-2.1), for workers who worked with the trunk in a minimum of 30 degrees of rotation for more than 10% of the working time (RR 1.3, 95% CI 0.9-1. 9), and for workers who lifted a load of at least 25 kg more than 15 times per working day (RR 1.6, 95% CI 1.1-2.3). CONCLUSIONS: Flexion and rotation of the trunk and lifting at work are moderate risk factors for low back pain, especially at greater levels of exposure.

Adult↗
PubMed2002

Sacral stress fractures: an unusual cause of low back pain in an athlete.

STUDY DESIGN: A case report of a sacral stress fracture causing low back pain in an athlete. OBJECTIVE: To document the occurrence of sacral stress fractures in athletes and to recommend it in the differential diagnosis of low back pain, especially in runners and volleyball players. SUMMARY OF BACKGROUND DATA: Low back pain is common both in the general population and in athletes. Athletes place high physical demands on their bodies, which often lead to stress fractures. Sacral stress fractures can cause back pain and are often not included in the differential diagnosis of back pain. METHODS: The authors were involved in the care and treatment of this patient and reviewed all medical records, radiologic tests, and related literature. RESULTS: In a 16-year-old volleyball player with a 4-week history of low back pain, magnetic resonance imaging of her pelvis revealed a stress fracture of the left sacral ala. She was treated with nonsteroidal anti-inflammatory agents, rest, and conditioning exercises and had a good functional outcome. CONCLUSION: Sacral stress fractures should be included in the differential diagnosis of athletes with low back pain, particularly runners and volleyball players. To the authors' best knowledge, this is the first report of a volleyball player with a sacral stress fracture. A review of the literature yielded 29 cases of sacral stress fractures in athletes, mainly runners.

Adolescent↗
PubMed1994

Predicting risk of back injuries, work absenteeism, and chronic disability. The shortcomings of preplacement screening.

Preplacement screening is put forth by some as an effective method for preventing low back disability at the workplace. Although there are still large gaps in knowledge regarding the natural history of and risk factors for back disability, it is clear that the majority of costs are derived from the small proportion of those that will suffer with back symptoms for 6 months or more. Thus, if preplacement screening is to have an impact on health care spending and compensation costs, the screening test will have to be predictive not so much of all back injuries, but rather of work absenteeism and especially chronic disability. This paper presents some criteria for evaluating a screening program and explores the effect of choosing different outcomes for evaluation. The literature on the effectiveness of a number of preplacement screening techniques is examined. Current legislation related to preplacement screening is also described. The natural history, etiologic factors, and prognostic markers for back injuries need to be elucidated further before effective screening strategies can be developed to reduce the incidence of back injuries and back disability in the population.

Absenteeism↗
PubMed2006

Treatment of chronic low back pain with successive injections of botulinum toxin a over 6 months: a prospective trial of 60 patients.

OBJECTIVES: The aim of this study was to evaluate the effects of two successive neurotoxin treatments for chronic low back pain using multiple pain rating scales in an open-label, prospective study. METHODS: Adult patients with chronic low back pain received multiple paraspinal muscle injections with a maximum dosing of 500 units of botulinum A toxin per session. Those with a beneficial clinical response received a second treatment at 4 months. Pain was assessed by visual analog scale (VAS), modified low back pain questionnaire (OLBPQ), and a clinical low back pain questionnaire (CLBPQ) at baseline, 3 weeks, 2 months, 4 months, and 6 months after the first treatment. RESULTS: Eighteen women and 42 men, ages 21 to 79 years (mean 46.6 years), with low back pain of a mean duration of 9.1 years were included. Significant improvement in back and radicular pain occurred at 3 weeks in 60% and at 2 months in 58% of the cohort. Beneficial clinical response to the first injection predicted response to reinjection in 94%. A significant minority of patients had a sustained beneficial effect from the first injection at 4 (16.6%) and 6 months (8.3%). Two patients had a transient flu-like reaction after the initial treatment. CONCLUSIONS: Botulinum toxin A improves refractory chronic low back pain with a low incidence of side effects. The beneficial clinical response is sustained with a second treatment.

Adult↗
PubMed2003

Gender differences in sick leave related to back pain diagnoses: influence of pregnancy.

STUDY DESIGN: A cross-sectional population-based study was conducted. OBJECTIVE: To investigate the influence of pregnancy on any gender differences in sickness absence related to back pain diagnoses in the group 16 to 44 years of age. SUMMARY OF BACKGROUND DATA: Back pain diagnoses are a major reason for sickness absence, especially among pregnant women. There is, however, little knowledge on the extent to which back pain during pregnancy may account for any differences in sickness absence when compared with men and nonpregnant women. METHODS: Data on sick leave periods certified by a physician were combined from two research databases: one including all insured persons (n = 50,167) and one including pregnant women (n = 1342) for the duration of 1 year. RESULTS: When pregnant women were subtracted from "all women," nonpregnant women had the same cumulative incidence of sickness absence related to back pain diagnoses as men. Among "all women" sick-listed with back pain diagnoses, 37% were pregnant, a finding not evident from official statistics. Sickness absence increased with age among nonpregnant women and men, but decreased among pregnant women. CONCLUSIONS: The proportion of sickness absence related to back pain diagnoses did not differ between nonpregnant women and men ages 16 to 44 years. The importance of back pain diagnosis as a reason for sickness absence may thus be overrated among nonpregnant women.

Adolescent↗
PubMed2003

Associations between back pain history and lumbar MRI findings.

STUDY DESIGN: Retrospective monozygotic twin cohort study. OBJECTIVES: Our goal was to investigate the associations between different spinal MRI findings and current, past year, and lifetime low back pain after adjusting for occupational physical loading, smoking, genetics, and early family influences. SUMMARY OF BACKGROUND DATA: The role of spinal pathology in back symptoms continues to be controversial. METHODS: The study participants consisted of 115 monozygotic male twin pairs 35 to 69 years of age. The qualitatively assessed MRI parameters were as follows: disc height, bulging, herniations, anular tears, osteophytes, spinal stenosis, and endplate changes. Signal intensity was measured quantitatively. RESULTS: After controlling for age, disc height was associated with all back pain variables studied and anular tears with LBP frequency and intensity during the 12 months before imaging. Both were associated with lifetime frequency of low back pain interfering with daily activities, disability, and intensity of the worst lifetime pain episode. Other MRI findings did not explain the various symptom histories. Adjusting for physical loading in the past 12 months increased the associations of anular tears and "low back pain today" and 12-month low back pain parameters. After controlling for genotype and other familial influences, the within-pair differences in disc height and anular tears accounted for 6% to 12% of the total variance in the within-pair differences of low back pain variables. CONCLUSION: These findings raise new questions about the underlying mechanisms of LBP. The sensitivities of the only significant MRI parameters, disc height narrowing and anular tears, are poor, and these findings alone are of limited clinical importance.

Adult↗
PubMed2003

Reliability, validity, and responsiveness of the short form 12-item survey (SF-12) in patients with back pain.

STUDY DESIGN: Secondary analysis of data collected from spine patients' normal clinic visits from 1998 to 2001. OBJECTIVE: To evaluate the reliability, validity, and responsiveness of the short form 12-item survey in patients with back pain. SUMMARY OF BACKGROUND DATA: The reliability, validity, and responsiveness of the short form 12-item survey in patients with back pain has not been previously evaluated. METHODS: Patients were asked to complete a comprehensive computerized survey questionnaire during their regular clinic visits. A total of 2520 patients who indicated in their first surveys that they had back pain were included in the study of the reliability and validity of the short form 12-item survey. Of these, 506 patients completed another survey within 3-6 months of follow-up and were included in the responsiveness evaluation. RESULTS: The two summary scales of the short form 12-item survey, physical component summary and mental component summary, demonstrated internal consistency reliability, with Cronbach alpha for both scales exceeding the recommended level of 0.70. Correlation of physical component summary and mental component summary with six other measures theoretically related or unrelated to these scales performed as expected without exception, demonstrating the construct validity of the short form 12-item survey. The responsiveness of the short form 12-item survey was supported by several pieces of evidence. First, the changes in physical component summary and mental component summary scores were correlated with the changes in back pain intensity. Second, for patients whose back pain improved, there was a significant increase in the follow-up physical component summary and mental component summary scores as compared to the baseline. Third, small to moderate effect size was observed for patients whose back pain became improved or became worse. CONCLUSIONS: The short form 12-item survey demonstrated good internal consistency reliability, construct validity, and responsiveness in patients with back pain.

Academic Medical Centers↗