Kugai Miyahito, Suyama Takehiro, Kitano Masahiko, Tominaga Yoshiko, Tominaga Shinsuke
Department of Neurosurgery, Tominaga Hospital.
No Shinkei Geka. 2020 Dec;48(12):1139-1145. doi: 10.11477/mf.1436204337.
The posterior inferior cerebellar artery(PICA)communicating artery is a fine tortuous artery that interconnects the bilateral vermian branches of the distal PICAs. Aneurysms of this anastomotic vessel have been reported in only seven cases(including ours)in the available literature. The PICA communicating artery supplied collateral blood flow to the contralateral vermian territory in all seven cases. A 51-year-old man presented with a rare PICA communicating artery aneurysm(which manifested as a hematoma in the fourth ventricle)and mild subarachnoid hemorrhage at the cerebellomedullary fissure. Angiography revealed a hypoplastic right PICA and a PICA communicating artery from the left PICA that supplied the right vermian territory; the ruptured aneurysm originated from this vessel. Aneurysm trapping is associated with the risk of cerebral infarction of the right vermian territory. We concluded that the distal part of the telovelotonsillar segment could be sacrificed because the right anterior inferior cerebellar artery and the superior cerebellar artery would supply collateral blood flow; therefore, we attempted trapping in this case. A bilateral midline suboccipital approach was used, and we detected a reddish fusiform aneurysm at the top of a hairpin curve of the PICA communicating artery in the uvula of the cerebellar vermis. The aneurysm was trapped and removed without complications. Histopathological evaluation confirmed findings of a true aneurysm. Congenital vulnerability of the arterial wall and hemodynamic stress are considered contributors to PICA communicating artery aneurysms. Preservation of the affected vessel is difficult in patients in whom aneurysmal clipping is challenging. Other vessels tend to establish collateral blood flow to the contralateral vermian territory in such cases. Trapping is a simple and effective therapeutic strategy for these aneurysms.
小脑后下动脉（PICA）交通动脉是一条纤细迂曲的动脉，它连接双侧PICA远端的蚓部支。在现有文献中，仅报道了7例（包括我们的病例）该吻合血管的动脉瘤。在所有7例病例中，PICA交通动脉为对侧蚓部区域提供侧支血流。一名51岁男性患者，表现为罕见的PICA交通动脉动脉瘤（表现为第四脑室内血肿）及小脑延髓裂轻度蛛网膜下腔出血。血管造影显示右侧PICA发育不良，有一条来自左侧PICA的PICA交通动脉为右侧蚓部区域供血；破裂的动脉瘤起源于该血管。动脉瘤夹闭术存在右侧蚓部区域脑梗死的风险。我们得出结论，由于右侧小脑前下动脉和小脑上动脉可提供侧支血流，因此可以牺牲终绒球扁桃体段的远端部分；所以，我们在该病例中尝试进行动脉瘤夹闭术。采用双侧枕下中线入路，我们在小脑蚓部小舌的PICA交通动脉发夹样弯曲顶端检测到一个红色梭形动脉瘤。成功夹闭并切除动脉瘤，未出现并发症。组织病理学评估证实为真性动脉瘤。动脉壁的先天性脆弱性和血流动力学应激被认为是PICA交通动脉动脉瘤的成因。对于动脉瘤夹闭术具有挑战性的患者，保留受累血管较为困难。在这种情况下，其他血管往往会为对侧蚓部区域建立侧支血流。动脉瘤夹闭术是治疗这些动脉瘤的一种简单有效的治疗策略。
