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 & 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.

Background and Purpose: Epidemiologic studies of low-back and neck pain are abundant, but research on mid-back pain is scant. No studies reporting the characteristics of mid-back pain in the general population were found. This study reports the one-year prevalence, severity, frequency and associated disability of mid-back pain, and compares these findings to those of neck and low-back pain.

Methods and Results: Male twins aged 35–70 years (n=600), from a general population sample, were interviewed with standardized questions. Stata’s survey methods were used to adjust for any correlation between the twins. The one-year prevalence of mid-back pain was 17.0% (95% CI 14.3–19.7) compared to 64.0% (95% CI 60.6–67.5) for neck and 66.8% (95% CI 63.4–70.3) for low-back pain. Among those reporting spinal pain, 55.1% with neck pain experienced frequent symptoms (daily to monthly), as compared to 33.3% with mid-back and 39.9% with low-back pain. The mean severity of the worst pain episode was highest for low-back pain, followed by neck and mid-back pain. Associated disability tended to be less common from mid-back pain (23.5%) than low-back (41.1%), with neck pain intermediate (30.3%). Mid-back pain was associated with higher likelihood of low-back and neck pain. Odds ratios for reporting neck and low-back pain were 2.32 (95% CI 1.53–3.51) and 2.86 (95% CI 1.80–4.54) higher, respectively, when mid-back pain was reported than when not.

Conclusion: The one-year prevalence of mid-back pain is approximately one-quarter that of neck or low-back pain, with associated disability tending to be less common. Other spinal co-morbidity is nearly always reported in cases of mid-back pain.