2017 年 45 巻 6 号 p. 464-470
To identify the best surgical strategies, we analyzed our experience with distal posterior inferior cerebellar artery aneurysms (distal PICA AN) and reviewed the literature. We treated 6 patients with ruptured distal PICA ANs. The ANs were located at the anterior medullary segment (AMs: 2 cases), lateral medullary segment (LMs: 2 cases), televelotonsillar segment (TTs: 1 case), and cortical segment (Cs: 1 case). The AN at the Cs was a feeder aneurysm of a cerebellar arteriovenous malformation (AVM). All patients underwent direct surgery. Prior to surgery, 3 ANs were diagnosed as saccular type, and the remaining 3 were considered fusiform types, based on digital subtraction angiography or computed tomography angiography. However, one case of fusiform type appeared saccular during intraoperative observation. Neck clipping for saccular type ANs and trapping combined with occipital artery-PICA bypass for fusiform type ANs were successfully performed. Sparing of perforating branches adjacent to the ANs was attempted as much as possible during the trapping procedure. A transcondylar fossa approach was selected for the proximal segment (AMs, LMs) of the distal PICA ANs to decrease the risk of lower cranial nerve palsies. Standard lateral suboccipital craniotomy for a TTs AN and midline suboccipital craniotomy for a Cs AN were performed. All patients recovered favorably without ischemic complications or lower cranial nerve palsies. Preparation for revascularization with bypass, preservation of the perforators, and approaches using skull base techniques enable a good surgical result for distal PICA ANs.
