A study on dysbaric osteonecrosis in caisson workers.

PURPOSE: To study the effects of exposure to compressed air on tunnel workers' health and to investigate the prevalence of dysbaric osteonecrosis (DON) in caisson workers.

METHODS: 128 tunnel workers were divided into the exposed group (n = 58) and the control group (n = 70), and their shoulders, hips and knees were examined with X-ray, computed tomography (CT) and magnetic resonance imaging (MRI).

RESULTS: 1) 34.5% of the exposed group were diagnosed with DON based on the national diagnostic criteria of decompression sickness. 2) The incidental difference of skeletal cystic changes between the exposed group and the control group was highly statistically significant (p < 0.01). 3) CT and MRI examination could detect early onset of DON lesions, and the cystic changes shown in CT and abnormal signals in MRI were diagnostic indicators in cases.

CONCLUSION: Cystic changes in CT and abnormal signals in MRI are key imaging findings of early DON.