Wider insurance coverage erased racial differences in who got minimally invasive surgery in Massachusetts, according to a new study. After the state increased access to insurance in 2006, racial disparities in the proportion of people having gallbladders or appendixes removed with minimally invasive techniques - versus traditional "open" surgery - disappeared, researchers found. "The Massachusetts experience provides a really unique and natural experiment to measure the effect of insurance expansion," Dr. Andrew Loehrer, the study's lead author from Massachusetts General Hospital in Boston, told Reuters Health.