The case report by Sicim et al. is the placement of extra-anatomical bypasses in bilateral common carotid arteries. The similar previous reports of the extra-anatomical bypass usually indicate unilateral bypass. Whether or not the Willis' circle is incomplete is difficult to judge during emergency surgery, and the authors' judgment seems to have been correct in the sense that it could maintain cerebral perfusion reliably and quickly. The direct perfusion and extraanatomical bypass of carotid artery is a reasonable strategy in patients with cerebral malperfusion.