European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society
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The aim of this study was to analyse the dynamic response of the human intervertebral disc to vibration in a physiologically relevant frequency spectrum. Eight lumbar intervertebral discs were harvested. After preparation, each sample was subjected to a pre-loading and then dynamic compression (from 5 to 30 Hz). ⋯ From 5 Hz to 30 Hz the stiffness values are between 0.19 and 3.66 (MN/m) and the damping values between 32 and 2094 (Ns/m). The mean resonant frequency was found at 8.7 Hz. These dynamic characteristics of the intervertebral disc could be used in a three-dimensional finite elements model of the human body to study its response to vibration in the driving position.
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The role of spinal implants in the presence of infection is critically discussed. In this study 20 patients with destructive vertebral osteomyelitis were surgically treated with one-stage posterior instrumentation and fusion and anterior debridement, decompression and anterior column reconstruction using an expandable titanium cage filled with morsellised autologous bone graft. The patients' records and radiographs were retrospectively analysed and follow-up clinical and radiographic data obtained. ⋯ Patient-perceived disability caused by back pain averaged 7.9 (range 0-22) in the Roland-Morris score at follow-up. In cases of vertebral osteomyelitis with severe anterior column destruction the use of titanium cages in combination with posterior instrumentation is effective and safe and offers a good alternative to structural bone grafts. Further follow-up is necessary to confirm these early results.
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There have been a large number of epidemiological studies demonstrating various primary factors that cause musculoskeletal disorders in middle-aged and older women. However, the relationship between low back pain and bone mineral density is not well documented, and no evidence for any direct relationship between the two has been found. To investigate the relationship, we conducted a cross-sectional study, on a population of 2,244 Japanese women aged 25-85 years who were participating in a regional health screening program. ⋯ Exercise and smoking were also significantly associated with low back pain. This association remained even after entering other lifestyle and reproductive factors into the final model. Accordingly, high bone mineral density would seem to be as important a public health problem as low bone mineral density and osteoporosis when considering the musculoskeletal symptoms and disabilities that appear in middle-aged women.