A controlled trial of an educational pamphlet to prevent disability after occupational low back injury.

STUDY DESIGN: Randomized controlled trial. OBJECTIVE: To test the ability of an educational pamphlet to improve recovery in terms of pain, work status, and health care utilization after occupational low back injury. BACKGROUND: Low back pain and disability persist as occupational health problems of epidemic proportions. Because interventions based on biomechanical models have had limited impact, recent educational approaches to preventing back problems have stressed psychosocial recovery issues. METHODS: A pamphlet was developed by compiling activity resumption, self-care, and attitudinal advice from recent publications. The pamphlet was sent at random to half of all consenting workers reporting back pain within 11 days of occupational injury between 7/96 and 6/97. Three and 6 months later, back pain, work status, health care use, and pamphlet impact outcomes were assessed through structured telephone interviews. RESULTS: Of the 726 eligible workers, 486 consented to participate. Consenters and nonconsenters and intervention and control groups were similar in initial demographic variables. The pamphlet had no statistically significant impact at the 0.05 significance level on pain severity or reduction, health care visits, or work absence. Of the 229 pamphlet recipients, 129 thought it had provided useful information, but only 25 thought it had helped them return to work more quickly. CONCLUSIONS: In this trial, a pamphlet stressing psychosocial recovery issues did not prevent or reduce postinjury pain, health care use, or work absence.

Early physician notification of patient disability risk and clinical guidelines after low back injury: a randomized, controlled trial.

STUDY DESIGN: Back-injured workers with high disability risk scores on a predictive questionnaire participated in a randomized, controlled trial of physician notification, with outcomes follow-up 3 months after injury. OBJECTIVES: To test whether physician intervention improves return to work and self-assessment outcomes for people at relatively high risk for disability. SUMMARY OF BACKGROUND DATA: Only a small number of back-injured workers suffer significant disability. Quick identification of these people would facilitate more efficient targeting and trials of interventions. Controlling variations in practice through practice guidelines has been recommended as a promising strategy for improving care and reducing disability. METHODS: Workers filing back injury reports responded to a disability prediction questionnaire. Those with high risk scores were randomly assigned to control or intervention groups. Patient-designated physicians in the intervention group received two letters identifying the patient's risk and making recommendations for care, including the Agency for Health Care Policy and Research's algorithms for acute low back pain. Predictive accuracy of the questionnaire and efficacy of physician intervention were evaluated on the basis of work status and self-assessments 3 months after injury. RESULTS: Of the 268 workers completing the questionnaire portion of the study, 32 (12%) were out of work because of back pain 3 months after injury. The questionnaire's predictive accuracy included maximum kappa of 0.277 and a receiver operating curve area of 0.78. Fifty-three people completed the physician intervention trial. The intervention had no significant impact on return to work, self-assessed pain, or satisfaction with health care. CONCLUSIONS: Stratification of back-injured people according to disability risk can can increase intervention efficiency by identifying those who require treatment and sparing those who do not. The apparent failure of risk notification and practice guidelines to reduce disability in this study may be improved by different application methods in the future.

Early prediction of chronic disability after occupational low back injury.

STUDY DESIGN: An inception cohort design was used to study a consecutive sample of back-injured workers. OBJECTIVE: To refine and to test the Vermont Disability Prediction Questionnaire's ability to indicate an individual's relative risk for chronic disability after occupational low back injury. SUMMARY OF BACKGROUND DATA: Although most back-injured workers return to work quickly, the minority who do not account for the majority of associated costs and health care. Early identification of workers at high risk for disability would facilitate intervention strategies. METHODS: During the study recruitment period, people aged 18-60 years reporting occupational low back injury to the Vermont Department of Labor and Industry within 11 days of onset were eligible. A Vermont Disability Prediction Questionnaire was mailed to the 442 subjects who could be contacted and who gave informed consent. One hundred sixty-three of the 166 subjects who completed and returned the questionnaire within 15 days of initial injury were telephoned 3 months later to determine work status. Those who returned the questionnaire were compared with those who would not consent or did not return the questionnaire in time according to age, sex, residence, wages, work hours per week, and length of employment. Employment status (inability to work because of low back pain) was evaluated by telephone interview 3 months after initial injury. RESULTS: The follow-up interviewer was blinded to the Vermont Disability Prediction Questionnaire scores. of the 163 subjects, 16 (10%) were not working because of low back pain. Using a simple dichotomous scoring system for 11 questionnaire items, a cut-off score of 0.48 identified 3-month postinjury work status, with 0.94 sensitivity and 0.84 specificity. CONCLUSIONS: The Vermont Disability Prediction Questionnaire is a brief, easily administered and scored tool for identifying back-injured workers at relative risk for chronic disability. Such early identification should increase the efficiency of disability prevention strategies by directing them toward people who need them most. The accuracy of the questionnaire needs to be tested in a variety of different clinical and socioeconomic settings.

Chronic low back pain and disability: the efficacy of functional restoration.

Chronic disability generates most of the costs associated with occupational low back pain, so the search for interventions that can reduce disability has been extensive. Outcome studies have been complicated by multiple study design and execution issues, as well as by the discrepancies between pain, impairment, and disability inherent in chronic pain populations. Differences in treatment program contents and in socioeconomic settings of the various trials of functional restoration must be considered in outcomes analysis. These differences suggest strategies for improving our future approach to reducing disability from occupational low back pain. Overall, functional restoration programs administered by well-integrated, multidisciplinary staffs can be very effective in reducing disability from occupational low back pain.

Spine update. Functional restoration.

Therapeutics as diverse as surgery, manipulation, and behavior modification can be intended to restore function for people with spinal disorders. However, the term "functional restoration" was coined by Tom Mayer and Vert Mooney to specify interdisciplinary programmatic care geared toward minimizing disability. Functional restoration emphasizes physical and behavioral improvements over pain eradication and relies heavily on guidance from repeated quantification of function. Unlike a comprehensive review, this report is meant to briefly update the reader on selected issues in functional restoration and to suggest directions for future developments.

Chronic low back pain: The relationship between patient satisfaction and pain, impairment, and disability outcomes.

STUDY DESIGN: Treatment outcomes for low back pain have been measured by varying standards of pain, impairment, and disability. This study examines the relationship between these three outcomes and treatment satisfaction in patients with chronic low back pain (CLBP). METHODS: Ninety CLBP patients underwent initial pain (VAS), impairment (PIS), and disability (OPQ) evaluations. RESULTS: Correlation coefficients between initial VAS, PIS, and OPQ were all less than 0.50. At 5-year follow-up, pain and disability scores were closely matched, more with lower mean scores among workers (P = 0.04 and 0.001). For 65 rehabilitation participants, 5-year patients satisfaction scores did not relate closely with VAS, PIS, and OPQ improvements during treatment (r = 0.15, 0.01, and 0.14). Five-year satisfaction correlated weekly with current pain and disability (r = 0.32, -0.36). Satisfaction levels were higher for workers after 1 year (P = 0.01), and after 5 years (P = 0.34. CONCLUSIONS: This study suggests that CLBP patients and their health care practitioners mutually set distinct pretreatment pain, impairment, and disability goals and judge outcomes accordingly.

Continuous passive motion in seating: a new strategy against low back pain.

Low back pain commonly reduces tolerance for the prolonged sitting required by many occupations and routine daily activities. In order to provide lumbar lordotic continuous passive motion (CPM), a pneumatic device was developed. This device includes a lumbar support bladder, which is cyclically inflated and deflated by a pump and valve system. This system is controlled by a timer and by pressure feedback from the bladder. The user selects cycle duration and support pressure. Using a simulated automobile setting, the first part of this study demonstrated that CPM produces lumbar lordotic motion and improved comfort for subjects without histories of low back pain. In the second part of the study, 28 people with chronic low back pain reported greater comfort using CPM during their routine motor vehicle operation. Further research is needed to determine whether this promising new strategy against low back pain can reduce occupational disability due to sitting intolerance.

Lifting capacity. Indices of subject effort.

The association between manual materials handling and occupational low back injuries has generated a wide variety of devices and protocols for testing lifting capacity. The validity of these tests depends critically on the subject's effort during the evaluation. This study compares the accuracy of several physiologic effort indices in identifying maximal and submaximal lifting efforts. Twenty-one men and twenty-three women free from back pain underwent isometric, isokinetic, and isoinertial tests of lifting capacity applying 50 and 100% efforts in random order. Effort indices included isokinetic force/distance curve variation, isoinertial peak force: weight ratios and peak force--weight differences, and heart rates and peak force variances for all three modes. Differences between 50 and 100% effort means were significant at P less than 0.01 for isokinetic force/distance curve variation, isoinertial peak force: weight ratios, and peak force--weight differences, and for heart rates in all three modes using analysis of variance. Differences were not significant (P greater than 0.05) for peak force variances in any mode using Wilcoxon Signed Rank Tests. According to a discriminant analysis model with optimal cutoff values, the only effort indices with better than 60% accuracy in identifying maximal and submaximal efforts were isokinetic force/distance curve variation (74%) and isoinertial peak force: weight ratios (69%), peak force--weight differences (62%) and heart rates (65%). For each index, subjects were divided into three groups according to whether their lifting outputs during 50% effort bouts were greater than, equal to, or less than one half their outputs in the 100% effort bouts.(ABSTRACT TRUNCATED AT 250 WORDS)

Disability exaggeration as a predictor of functional restoration outcomes for patients with chronic low-back pain.

Many of the individual biological, psychological, and social factors attributed to low-back disability have been tested previously for their ability to predict treatment outcomes. To test the assumption that disability exaggeration affects treatment outcomes, models were developed to quantify this complex characteristic and to test its predictive value. Two hundred fifty-eight patients with chronic back disability entering a program of functional restoration were initially evaluated with a battery of tests, including measurements of trunk flexibility, lifting capacity, cycling endurance, self-assessments of pain and disability, and psychological attributes. On the basis of these measurements, patients were characterized as disability exaggerators if by peer comparison their self-assessments of pain and disability were in the most severe range despite high levels of physical capacity. Program completion and work status 1 and 2 years after treatment were compared between disability exaggerators and their peers. Individual initial attributes associated with program completion included pain intensity and Million Visual Analogue scores, lifting capacity, trunk flexibility, some Minnesota Multiphasic Personality Inventory and Million Behavioral Health Inventory scales, and cigarette smoking. One-year re-employment was associated with Minnesota Multiphasic Personality Inventory Scale 8, Wechsler Adult Intelligence Score-Revised, and cycling endurance. There were no significant associations between any individual factor and 2-year work status. Only two of the 12 disability exaggeration models distinguished between program graduates and dropouts, and none of the models accurately predicted return to work following treatment. Prescription of intensive multidisciplinary treatment should not be denied on the basis of any individual patient attribute or of disability exaggeration, as measured in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Dynamic lifting capacity: the relationship between peak force and weight as an indicator of effort.

Quantification of lifting capacity has become a major component in clinical and occupational evaluations of people with or at risk for low back pain. The ideal test of maximum acceptable lifting would include an index of subject effort. Heart rate response appears to have significant limitations as an indicator of effort. In this study a device that records vertical lifting force measured peak force/weight ratios (PF/W) and differences (PF-W) for individual lifts. Seventeen men without low back pain lifted the device with progressively heavier loads. The PF/W, PF-W, and heart rate responses were compared at half-maximum and maximum effort levels. The PF/Ws were higher, while the PF-Ws and heart rate responses were lower during half-maximum efforts. As an indicator of subject effort, the relationship between peak force and weight may play a key role in isoinertial lifting evaluations.

Isokinetic trunk-strength deficits in people with and without low-back pain: a comparative study with consideration of effort.

The purposes of this study were to determine (a) the degree and distribution of isokinetic trunk strength deficits in people with chronic low-back pain (CLBP) and (b) to what degree subject effort during testing affects those deficits. We measured the isokinetic trunk strengths of three subject groups on the Cybex Trunk Extension/Flexion machine. Groups 1 and 2 consisted of 155 men and women with CLBP who were divided into maximal (n = 115) and submaximal (n = 40) groups according to their torque/position curve variability. Group 3 was made up of 32 back-healthy men and women who served as controls. The results demonstrated that men had higher flexion and extension torques than women did for all groups. The control group had higher flexion and extension torques than the maximal-effort CLBP group did. The extensors had a proportionally greater deficit than the flexors did in this LBP group. Comparing the two groups with CLBP, the maximal-effort group had higher flexion and extension torques than the submaximal effort group did, and the extensors showed a greater deficit. Degree of effort during testing does affect the results. Therapists should consider extensor strengthening and reeducation exercises when designing exercise programs to restore normal function in people with chronic CLBP.

Effects of axis placement on measurement of isokinetic flexion and extension torque in the lumbar spine.

We wanted to ascertain whether changing the machine axis placement relative to the anatomic landmarks of a tested subject in isokinetic flexion and extension trunk strength would influence the measurements obtained. Twenty healthy volunteers were tested with the machine axis intentionally displaced from a reference position at the lumbosacral junction. Displacing the axis 50 mm vertically produced on average 15% increase in the torque produced, and displacing it 10 mm horizontally produced approximately 5% reduction in torque, independent of the direction of displacement from the reference position. The angle at which maximum torque occurred and the ratio of extension to flexion torque were unaffected by axis placement. Intertester reliability in axis placement was found experimentally to produce variations of usually less than 10 mm. We conclude that isokinetic trunk strength measurement is affected by testing axis placement; this should be controlled, especially in repetitive testing of the same individual.

Functional restoration with behavioral support. A one-year prospective study of patients with chronic low-back pain.

Patients with chronic disabling low-back pain have poor prospects of returning to work. The authors tested a treatment program of functional restoration with behavioral support through 1 year prospective observation of patients disabled for an average of 19 months without evidence of surgically correctable disease. Ninety patients were studied: 59 program graduates, five program dropouts, 17 patients denied program authorization by their insurance carriers, and six crossover patients. Three patients were admitted but refused to participate in the treatment program. Initial demographic, physical, and self-assessment attributes were similar for all four groups. At year's end, 81% of program graduates, 40% of the dropouts, and 29% of those denied the program had returned to work. All six crossover patients were working 6 months after treatment. Program graduates showed significant improvements in self-assessed pain, disability, and depression, and in physical capacities after 3 weeks of treatment. These improvements were maintained through the year except for partial decreases in frequent lifting, cycling endurance, and isokinetic trunk extension strength. Functional restoration with behavioral support is an effective treatment for patients with chronic, disabling low-back pain, as measured by self-assessments, physical capacities, and return to work.

Isokinetic trunk and lifting strength measurements: variability as an indicator of effort.

This study examines the hypothesis that force/distance curve variability distinguishes submaximal from maximal efforts in isokinetic trunk and lifting strength tests. Thirty normal subjects were tested on the Cybex Trunk Extension/Flexion (TEF) and Liftask (LT) machines during maximal (100%) and submaximal (50%) efforts. Considering each test separately, visual assessments of curve variability were indeterminate of degree of effort in 28% of TEF and 34% of LT tests. Measurement models of curve variability were more clearly discriminating. When a given subject's test curves were considered together, scaled visual assessments identified the degree of effort in 91% of TEF and 86% of LT results. The measurement models were accurate 90-92% of TEF and 79-92% of LT results. Clinical judgment is required in evaluating effort during tests of isokinetic trunk and lifting strength.