Whole-body vibration and disorders of the spine.

This cross-sectional study is based on interviews and medical examinations of 352 operators of earth-moving machines who had been exposed to whole-body vibrations for at least three years. In addition, available X-rays showing different parts of the spines of 251 machine operators who had been exposed to vibration for at least ten years were used for evaluation. One hundred and forty-nine of the operators were asked about discomfort occurring immediately after an eight-hour work shift. The group of exposed persons was compared with a control group of 215 non-exposed persons. The percentage of subjects reporting spinal discomfort was much higher for the exposed group than for the non-exposed group. 68.7% of the operators complained of spinal discomfort in the lumbar spine, 6.8% in the thoracic column and 18.2% in the cervical column. The discomfort reported immediately after an eight-hour exposure to whole-body vibration was highly age-dependent. The epidemiological study resulted in an objective conformation of the spinal discomfort reported, 2/3 of which were related by the operators to the lumbar syndrome. Lumbar syndrome (81%) accounted for by far the highest number of spinal disorders. Examinations of the operators with at least ten years of exposure to whole-body vibrations showed that morphological changes in the lumbar spine occur earlier and much more frequently than in the case of non-exposed persons. Problems of etiology and pathogenesis are discussed.