Association of occupational direct radiation exposure to the hands with longitudinal melanonychia and hand eczema in spine surgeons: a survey by the society for minimally invasive spinal treatment (MIST)

PURPOSE To investigate the association between occupational direct radiation exposure to the hands and longitudinal melanonychia (LM) and hand eczema in spine surgeons. METHODS A web-based questionnaire survey of the Society for Minimally Invasive Spinal Treatment (MIST) in Japan was conducted. The proportion of LM and hand eczema in hands with high and low-radiation exposure was compared using Fisher's exact test. The odds ratios (ORs) and their 95% confidence intervals (CIs) for the prevalence of LM and hand eczema in the high-radiation exposure hands were calculated using generalized estimating equations for logistic regression as control for the correlation of observations among the same individuals and possible confounders. RESULTS Among 324 members of the society, responses were received from 229 members (70.7%). A total of 454 hands from 227 participants were analysed. The prevalence of LM and hand eczema was 43% and 29%, respectively. In a hand-by-hand comparison, more hands had LM in the high-radiation exposure group than the low-radiation exposure group (90 [40%] vs. 39 [17%], respectively, p < 0.001). A similar trend was observed for hand eczema (63 [28%] vs. 33 [15%], respectively, p = 0.001). The adjusted OR for high-radiation exposure hands was 3.18 (95% CI: 2.24-4.52). Consistent results were obtained for hand eczema, with an adjusted OR of 2.26 (95% CI: 1.67-3.06). CONCLUSION The present study suggests that direct radiation exposure to physician's hands is associated with LM and hand eczema. Those with LM and radially biased hand eczema may have had high direct radiation exposure.