Load and activity changes of the spine typically cause symptoms of nerve root compression in subjects with spinal stenosis. Protrusion of the intervertebral disc has been regarded as the main cause of the compression. The objective was to determine the changes in the size of the lumbar spinal canal and especially those caused by the ligamentum flavum and the disc during loaded MRI. For this purpose an interventional clinical study on consecutive patients was made. The lumbar spines in 24 supine patients were examined with MRI: first without any external load and then with an axial load corresponding to half the body weight. The effect of the load was determined through the cross-sectional areas of the spinal canal and the ligamentum flavum, the thickness of ligamentum flavum, the posterior bulge of the disc and the intervertebral angle. External load decreased the size of the spinal canal. Bulging of the ligamentum flavum contributed to between 50 and 85% of the spinal canal narrowing. It was concluded that the ligamentum flavum, not the disc had a dominating role for the load induced narrowing of the lumbar spinal canal, a finding that can improve the understanding of the patho-physiology in spinal stenosis.

PurposeEvidence-based facts regarding spine abnormalities and back pain are needed in order to develop rehabilitation programs and prevent spine injuries in young skiers. The aim therefore is to identify MRI changes in the thoraco-lumbar spine and the lifetime prevalence of back pain, as well as the association between them, in young skiers compared to non-athletes.MethodsSeventy-five young elite alpine and mogul skiers, age range 16–20 years, were compared with 27 non-athletic controls. All subjects underwent spinal MRI and answered back pain questionnaires.ResultsFifty-six percent of skiers had at least one disc Pfirrmann grade ≥3 compared to 30% of controls (p = 0.027). Schmorl’s nodes (46%) and disc height reduction (37%) were significantly more prevalent in skiers compared to controls (0%) (p < 0.001). When all parameters were combined together, skiers had significantly higher rate of radiological changes than controls, 82% compared to 54% (p = 0.007). The mean number of discs with Pfirrmann grade ≥3 was 1.1 per individual in skiers (median 1, range 0–6) versus 0.6 in controls (median 0, range 0–3). There was no significant difference in lifetime prevalence of back pain between skiers (50%) and controls (44%) (n.s.). MRI abnormalities in skiers did not correlate with lifetime prevalence of back pain. Skiers had a better health perception than controls (p = 0.026).ConclusionAlpine skiers have more degenerative disc changes compared to non-athletes, but these changes do not correlate with the lifetime prevalence of back pain. Lifetime prevalence of back pain is not significantly different between the groups; however, skiers report more severe pain on VAS score.Level of evidenceII.

alMRI instantaneously induces T2-value changes in lumbar discs and is, thus, a feasible method to reveal dynamic, biochemical disc features in patients with chronic LBP.