What are the treatment options for blister-like aneurysms?

Treatment of blood blister-like aneurysms (BBAs) of the supraclinoidal internal carotid artery (ICA) is challenging and the optimal treatment is yet to be defined. The treatment options for ICA BBAS are microsurgery, endovascular therapy, or a combination of the two. The microsurgical armamentarium consists mainly of direct aneurysm clipping with or without protective EC-IC bypass, clip-wrapping, or trap ligation with ICA sacrifice with or without EC-IC bypass. The endovascular treatment options are mainly endovascular ICA ligation, multiple overlapping stents (≥ 3) with or without coiling, covered stents, or flow diverters. In four recent meta-analyses of BBAs, neither microsurgical nor endovascular therapy had an impact on clinical outcome in multivariate analysis. Microsurgery offered aneurysm obliteration rates superior to endovascular techniques, but came at a higher risk of intraoperative bleeding. Endovascular therapy increased the likelihood of a second treatment, conversion to another treatment modality, and incomplete aneurysm obliteration. In this review, we discuss pros and cons of the above approaches while adding our own viewpoints to the discussion.