Outcome assessment in low back pain: how low can you go?

The present study examined the psychometric characteristics of a core-set of six individual questions (on pain, function, symptom-specific well-being, work disability, social disability and satisfaction) for use in low back pain (LBP) outcome assessment. A questionnaire booklet was administered to 277 German-speaking LBP patients with a range of common diagnoses, before and 6 months after surgical (N=187) or conservative (N=90) treatment. The core-set items were embedded in the booklet alongside validated reference questionnaires: Likert scales for back/leg pain; Roland and Morris disability scale; WHO Quality of Life scale; Psychological General Well-Being Index. A further 45 patients with chronic LBP completed the booklet twice in 1–2 weeks. The minimal reliability (similar to Cronbachs alpha) for each core item was 0.42–0.78, increasing to 0.84 for a composite index score comprising all items plus an additional question on general well-being (quality of life). Floor or ceiling effects of 20–50% were observed for some items before surgery (function, symptom-specific well-being) and some items after it (disability, function). The intraclass correlation coefficient (ICC) (test–retest reliability) was moderate to excellent (ICC, 0.67–0.95) for the individual core items and excellent (ICC, 0.91) for the composite index score. With the exception of symptom-specific well-being, the correlations between each core item and its corresponding reference questionnaire (validity) were between 0.61 and 0.79. Both the composite index and the individual items differentiated (P<0.001) between the severity of the back problem in surgical and conservative patients (validity). The composite index score had an effect size (sensitivity to change) of 0.95, which was larger than most of the reference questionnaires (0.47–1.01); for individual core items, the effect sizes were 0.52–0.87. The core items provide a simple, practical, reliable, valid and sensitive assessment of outcome in LBP patients. We recommend the widespread and consistent use of the core-set items and their composite score index to promote standardisation of outcome measurements in clinical trials, multicentre studies, routine quality management and surgical registry systems.     

How low can we go?

Editor—In his editorial,¹ Prof. Sneyd stresses the needfor large prospective studies addressing the effect of bispectralindex (BIS) monitoring on the risk of awareness. What may haveescaped him is that preliminary results from just     

How low can we go?

Intraoperative awareness is a terrifying experience, which patientsfear and anaesthetists are anxious to avoid; any clinician whodoubts this should read a first hand account.¹ Since the early1990s, the Bispectral Index (BIS) has been developed as a measureof hypnosis during anaesthesia and sedation. As BIS is a linearizedand monotonic measure, clinicians have become comfortable withthe idea that an increase in BIS may warn of actual or impendingawareness. Although     

Does unspecific low back pain really exist?

Only 20 % of low back pain or sciatica is of a specific origin. These specific pain conditions include tumours, spondylitis, rheumatic and metabolic diseases as well as radicular syndromes. By far the most pain from discs, facet and sacroiliac joints, ligaments and muscles must be considered as unspecific, because no anamnestic information or clinical signs exist (radiological changes included) to assign pain to structural or functional correlates. In addition, the therapeutic consequences from the assignment of structural changes to pain remain unclear. In acute pain situations the specificity of the pain is not important because of the fast relief of the disease, in chronic pain situations, fear avoidance beliefs and pain behaviour seem to be much more important than structural and functional changes.     

Do functional tests predict low back pain?

STUDY DESIGN: A cohort of 307 nonsymptomatic workers and another cohort of 123 workers with previous episodes of low back pain were followed up for 2 years. The outcomes were measured by symptoms, medical consultations, and sick leaves due to low back disorders. OBJECTIVES: To study the predictive value of a set of tests measuring the physical performance of the back in a working population. The hypothesis was that subjects with poor functional capacity are liable to back disorders. SUMMARY OF BACKGROUND DATA: Reduced functional performance has been associated with back pain. There are few data to show whether reduced functional capacity is a cause or a consequence of pain. METHODS: Mobility of the trunk in forward and side bending, maximal isokinetic trunk extension, flexion and lifting strength, and static endurance of back extension were measured. Standing balance and foot reaction time were recorded with a force plate. Clinical tests for the provocation of back or leg pain were performed. Gender, workload, age, and anthropometrics were managed as potential confounders in the analysis. RESULTS: Marked overlapping was seen in the measures of the subjects with different outcomes. Among the nonsymptomatic subjects, low performance in tests of mobility and standing balance was associated with future back disorders. Among workers with previous episodes of back pain, low isokinetic extension strength, poor standing balance, and positive clinical signs predicted future pain. CONCLUSIONS: Some associations were found between the functional tests and future low back pain. The wide variation in the results questions the value of the tests in health examinations (e.g., in screening or surveillance of low back disorders).     

Is occupational low back pain on the rise?

STUDY DESIGN: A retrospective analysis of back pain claim data from two sources, a workers' compensation provider and Washington State Department of Labor and Industries. The Workers' Compensation Provider claim data were examined over a 9-year period, 1987-1995, and the Washington claim data were examined over a 5-year period, 1991-1995. In addition, a third source of data, reports of back pain from the the Bureau of Labor Statistics, was examined over a 4-year period, 1992-1995. OBJECTIVES: To characterize occupational low back pain trends in the United States. More specifically, trends in back pain rates and costs as well as back injury rates from the Bureau of Labor Statistics were discerned. SUMMARY OF BACKGROUND DATA: The literature often refers to a recent rise in occupational low back pain. However, the question is: Do empirical data support this notion? METHODS: Retrospective analysis of workers' compensation provider, Washington State, and Bureau of Labor Statistics data. RESULTS: The U.S. estimate of the annual low back pain claim rate decreased 34% between 1987 and 1995, although the trend was not monotonic. There was a sharper decrease in the U.S. estimate of the annual low back pain claim costs during this time (58%). In 1995, however, occupational low back pain remained a major problem in the U.S.: an estimated $8.8 billion was spent on low back pain claims, and the rate of filing low back pain claims was 1.8 per 100 workers. CONCLUSIONS: Evidence of a rise in occupational low back pain was not discerned for the 8-year period studied. Data from three sources support this finding. However, occupational back pain remains a major problem in the U.S.     

Adolescent idiopathic scoliosis. Is low melatonin a cause?

BACKGROUND: Although the cause of adolescent idiopathic scoliosis remains unclear, pinealectomy is followed by the development of scoliosis in chickens. Melatonin is the only hormone secreted by pineal gland. OBJECTIVE: To assess serum melatonin levels in adolescents with idiopathic scoliosis. METHODS: Serum melatonin was assayed once, at 12:00 hours, in each of 20 adolescents with idiopathic scoliosis and 10 age-matched siblings. In the patient group, mean age was 14.3 years and the mean Cobb angle was 54.5 degrees (range, 20 degrees-110 degrees). Mean age in the control group was 14 years. RESULTS: Serum melatonin was significantly lower in the patients (mean, 7.7 pg/mL; range, 4 to 13 pg/mL) than in the controls (mean, 29.9 pg/mL; range, 19.3 to 46 pg/mL) (P < 0.00001). The 12 surgically treated patients had a mean melatonin level of 8.1 pg/mL, versus 7.2 pg/mL in the eight other patients (nonsignificant P and regression coefficient values). Serum melatonin was not significantly correlated with the Cobb's angle (regression coefficient, 0.18; P < 0.44). CONCLUSION: Our data suggest that serum melatonin levels may contribute to the pathogenesis of idiopathic scoliosis.     

Is every chronic low back pain benign? Case report

BACKGROUND: There is a well-recognized association between chronic back pain and the existence of an AAA. In literature, there are few reported AAA cases that describe patients with extensive pressure erosion of the vertebral body. CASE DESCRIPTION: The authors present the case of a 38-year-old woman with chronic low back pain for the last 2 years in whom an AAA was formed during the follow-up period. The patient presented with an episode of low back pain following hard work 2 years ago. MR imaging of the lumbar spine was reported as disc degeneration at the L4-5 and L5-S1 levels. She was given medical treatment and was doing well with occasional back pain for a year. One year later, she suffered another disabling pain attack, and MR imaging revealed an additional focal disc protrusion at the L4-5 level. She was again medically treated. In August 2004, she presented with severe low back pain, and this time, MR imaging showed edema and erosion at the anterior part of L3 vertebra body. MR imaging studies (2- and 3-dimensional) depicted AAA as the cause. She was operated on, and the aneurysm was resected with graft repair of the site. She was pain-free in the postoperative period. CONCLUSIONS: The evaluation of a patient with chronic back pain needs a thorough clinical and radiological workup. Limited evaluation of the bony and nervous structures of the spinal canal radiologically is insufficient. Pre- and paravertebral structures as well as vertebral body should carefully be evaluated to diagnose other causes of pain.     

Low-dose low–molecular-weight heparin is anti-inflammatory during venous thrombosis

Purpose: Venous thrombosis results in a vein wall inflammatory response initiated by thrombus. Although anticoagulation with standard heparin (SH) and low–molecular-weight heparin (LMWH) is known to limit further thrombosis, their anti-inflammatory properties are poorly defined. The anti-inflammatory properties of these heparins were studied. Methods: Sprague-Dawley rats were divided into groups and underwent inferior vena caval (IVC) ligation just below the renal level producing IVC thrombosis. One hour before ligation, animals received subcutaneous SH or LMWH at either high or low dose; normal saline (NS) was used as control. Six hours after ligation, animals were killed, and the IVCs were analyzed for clot presence, vein wall morphometrics, and vein wall permeability (VP) to define injury. Results:Animals in both low-dose groups had no measurable anticoagulation, whereas those in both high-dose groups were adequately anticoagulated. There were statistically less IVC neutrophils for all groups compared with the control group, with low-dose LMWH showing the least cells (low-dose LMWH, 16 ± 3; high-dose LMWH, 37 ± 10; low-dose SH, 37 ± 6; high-dose SH, 32 ± 9; NS control, 63 ± 2). Similar results were noted for total inflammatory cells. The lowest VP was noted for low-dose LMWH. Conclusion: Although both SH and LMWH inhibited vein wall neutrophils and total inflammatory cells, low-dose LMWH was most effective limiting neutrophil extravasation and was the only intervention to decrease VP below control levels. This occurred without preventing thrombus formation or causing a state of anticoagulation. Low-dose LMWH possesses anti-inflammatory properties distinct from its anticoagulant properties. (J Vasc Surg 1998;28:848-54.)