The exclusion criteria removed patients with “chronic therapy capable of interfering with bone metabolism,” but we are not told what those therapies were, nor are we told what treatment or conditions were accepted. But the most obvious problem with this study is that it is not randomized. Seventy patients were offered LVRS, but only 40 underwent resection. The other 30 patients served as the retrospective control group. Are they really adequate control subjects? Isn’t selection bias possible? Perhaps their refusal to undergo surgery alone led to the observed differences in the two groups. Perhaps the actual performance of the LVRS had nothing to do with the increased bone mineral density (BMD) in the treated group, rather those that wanted surgery were more motivated, more physically active, or had a better mental outlook on their disease state. Perhaps they had some other quality linked to wanting to undergo a relatively risky operation that leads to improvement in health and BMD that we cannot measure. This study, like any other nonrandomized study, suffers from all the inherent problems of a retrospective study.