Purpose and Background: Cerebrospinal fluid (CSF) is used as an intrabody reference for quantitative disc signal intensity measurements in the lumbar spine, but may be less ideal for investigating thoracic disc degeneration. The purpose of this study was to investigate the spinal cord as an alternative intrabody reference for thoracic disc signal intensity measurements.

Methods: T2-weighted MR images from the thoracic spine (T6-T12) were obtained using two 1.5-Tesla scanners from a population-based sample of 523 men (35–70 years). Quantitative data on signal intensities of the disc, CSF and spinal cord were acquired using custom-made software. The signal intensity of the spinal cord was correlated with the signal intensity of the adjacent CSF (criterion reference) in a sample of subjects with visually clean CSF-samples. The measured disc signal intensities were correlated with age in three ways; without adjustment and adjusting for CSF and spinal cord. Pearson’s r was used for the correlations and intraclass correlation coefficient (ICC) to examine the interobserver repeatabilities of spinal cord signal intensity measurements.

Results: Spinal cord signal intensity measurements were repeatable (ICC=0.99–1). Clean CSF-samples correlated highly with the signal intensities of the spinal cord (r=0.91–0.99). The correlations of spinal cord-adjusted disc signal intensity with age (r=−0.30 to −0.40) were somewhat higher than for age and CSF-adjusted disc signal intensity (r=−0.26 to −0.36). In comparison, correlations between unadjusted disc signal intensity and age were low (r=−0.11 to −0.19).

Conclusion: Spinal cord is a good alternative intrabody reference to the current gold standard (CSF) for disc signal intensity measurements in the thoracic spine.

Purpose: Functional Capacity Evaluations (FCEs) are batteries of tests designed to measure patients’ ability to perform work-related activities. Although FCEs are used world-wide, it is unknown how patients’ performances compare between countries or settings. This study was performed to explore similarities and differences in FCE performance of patients with chronic low back pain (CLBP) between three international settings that utilise the same FCE protocol.

Methods: Standardised FCEs were performed on three cohorts of patients with CLBP: a sample from an outpatient rehabilitation context in the Netherlands (n=121), a Canadian sample in a Worker’s Compensation context (n=273), and a Swiss sample in an inpatient rehabilitation context (n=170). Patients were undergoing FCE as part of their usual clinical care. Means and standard deviations of maximum performance on the FCE material handling items were calculated and differences compared using ANO VA. Multivariable linear regression was used to determine the relationship between country of origin and FCE performance while controlling for potential confounders including, age, sex, duration of back pain problems, and self-reported pain and disability ratings.

Results: Compared to the Dutch sample, the mean performance of patients in the Canadian and Swiss samples was consistently lower on all FCE items. This association remained statistically significant after controlling for potential confounders.

Conclusions: Considerable differences were observed between settings in maximum weight handled on the various FCE items. Future FCE research should examine the effects of a number of potentially influential factors, including variability in evaluator judgements across settings, the evaluator-patient interaction and patients’ expectations of the influence of FCE results on disability compensation.

Accepted: Disability & Rehabilitation 2006

Purpose & Relevance: To examine the prevalence of degenerative findings in the thoracic spine in a population sample of adult men. Normative data on thoracic degenerative findings provide an essential reference for related observations in patients.

Methods & Results: Qualitative and quantitative assessments of thoracic disc degeneration were obtained from MRI (levels T6-L1) for general population sample of 532 men aged 25–70 years. Qualitative assessments of disc degeneration were performed by an experienced spine surgeon and custom-made software was used to acquire quantitative assessments. Descriptive statistics were acquired using SPSS. Moderate or severe disc bulging was present in at least one disc in 7.9% of subjects, with bulging most common at the two lowest levels. The prevalence of disc herniations was 0.8%. Moderate or severe disc height narrowing was present in 2.7% to 9.7% by disc level with 22.4% of subjects having at least one narrowed disc. Four or more wedged vertebrae (≥ 5°) were present in 68 subjects and 13 (2.4%) had coexisting Schmorl’s nodes. Seven subjects (1.3%) met more stringent criteria for Scheuermann’s disease, with three or more wedged vertebrae, endplate changes, sclerosis and disc height narrowing. Of the variables examined, disc signal intensity correlated highest with age (r= 0.31–0.40, depending on disc level).

Conclusion: The prevalence of disc degeneration appears lower in the thoracic spine than previously reported in the lumbar spine. However, one-fifth of the subjects have markedly narrowed discs, which have been associated with symptom history in the lumbar spine. Disc signal intensity is the finding most highly associated with age.