Effects of vibration on the hand-arm system of miners in India

Sixty-six Jackhammer drillers and 35 blasters from two mines were clinically screened for hand-arm vibration syndrome (HAVS). The screening consisted of questionnaire-based information, clinical examination including measurement of phalangeal circumferences of fingers (FCT) and motor nerve conduction (MCV) studies. In a warm environment, the prevalence of symptom complexes suggested the existence of peripheral neuropathy and musculoskeletal abnormalities rather than any peripheral circulatory disorders. Clinical examination revealed soft tissue wasting in the hands (26 cases), ulnar nerve impairment (23 cases), median nerve impairment (16 cases) and Dupuytren's contracture (4 cases). Mean motor nerve conduction velocities of 59 out of 66 drillers who volunteered for this assessment were not significantly different from those of the 35 blasters. The results of their correlation coefficients varied considerably for MCVs when age and years of vibration exposure underwent regression analysis. However, comparison of MCV and FCT of 30 drillers with 30 matched blasters revealed that the mean MCV of the right median nerve in the vibration exposed group was significantly decreased (p<0.01) and for the mean FCT, the proximal phalanxes of the right index finger, left thumb and left ring fingers were thinner in the vibration exposed group (p<0.05).