According to previous research, the presence of emphysema is one major cause that induces pneumothorax.3 However, Hallifax et al1 did not mention this factor in their study, nor did they explain why thoracoscopy failed in 13 cases. In our experience, pneumothorax will commonly occur in patients with apparent emphysema, especially when pulmonary bullae are unavoidable in the focus puncture path. We already listed emphysema as the relative contraindication of this operation, since it may induce life-threatening pneumothorax. Moreover, pneumothorax is very likely to occur when peripheral lesions are close to the pleura, especially when the peripheral lesions do not obviously invade or adhere to the pleura. Thus, Hallifax et al1 should further elaborate the relevant patients’ clinical data.