Miyagi A, Maeda K, Sugawara T
Department of Neurosurgery, Higashijyujyo Hospital, Tokyo, Japan.
No Shinkei Geka. 1997 Jun;25(6):537-41.
We report a case of distal posterior inferior cerebellar artery (PICA) aneurysm associated with acute subdural hematoma (SDH). The patient was a 68-year-old female who was found unconscious at home and transferred to the emergency medical center in a state of deep coma. Her consciousness on admission to the center was 200P (Japan coma scale), E1V1M2 (Glasgow Coma Scale), and the Hunt & Kosnik grade was grade IV. She was in a state of decerebrate condition. Computed tomography (CT) scans revealed diffuse subarachnoid hemorrhage that was located mainly in the posterior fossa, as well as intraventricular hemorrhage in the third and fourth ventricles. It also disclosed an intracerebellar hematoma (ICH) of the vermis and an acute SDH of the left posterior fossa. The first cerebral angiographic examinations on admission demonstrated no aneurysm. However, emergency surgery was performed immediately in order to improve her poor condition. Ventricular drainage and removal of the acute SDH were carried out. Postoperatively, her consciousness improved gradually to 20P. Ventricular peritoneal shunt was performed three weeks later. Her consciousness improved up to 3P and she showed only slight truncal ataxia. She was admitted to our hospital for rehabilitation at two months after the first surgery. Repeated angiography was performed and demonstrated an aneurysm in the telovelotonsillar segment of the left PICA. The aneurysm was successfully clipped via a midline suboccipital approach. Her postoperative course was uneventful, and she continues to undergo rehabilitation. Aneurysms of the posterior fossa associated with acute SDH are extremely rare. Only two cases have been reported for distal PICA aneurysm cases. The CT scans in our patient revealed not only SAH but also SDH in the posterior fossa and ICH in the vermis. Over 100 cases of distal PICA aneurysms have been described in the literature. We analyzed the relationship between the portions with the ruptured aneurysms and CT findings. Aneurysms which were located at the proximal portion of the distal PICA mainly showed SAH and IVH. On the other hand, ICHs of the vermis and cerebellum were characteristic CT findings of ruptured aneurysms which were located more distal to the telovelotonsillar segment, and were evident in 14% of cases of such aneurysms. ICH and SDH were not found in aneurysms which were located in portions more proximal to the telovelotonsillar segment. These characteristic findings were related to the complex anatomical courses of the PICA. The distal portions of the PICA run between the vermis and cerebellar hemisphere, so that if an aneurysm ruptures at these portions, ICHs in the vermis and cerebellum tend to occur. In cases such as ours, because of the characteristic CT findings, effort to detect a distal PICA aneurysm should be made at first surgery, along with ventricular drainage and removal of the SDH. The surgical procedures and outcome of cases with distal PICA aneurysms are also discussed.
我们报告一例伴有急性硬膜下血肿（SDH）的小脑后下动脉（PICA）远端动脉瘤。患者为68岁女性，在家中被发现昏迷，随后被转送至急诊医疗中心，处于深度昏迷状态。她入院时的意识状态为200P（日本昏迷量表），E1V1M2（格拉斯哥昏迷量表），Hunt & Kosnik分级为IV级。她处于去大脑强直状态。计算机断层扫描（CT）显示弥漫性蛛网膜下腔出血，主要位于后颅窝，以及第三和第四脑室的脑室内出血。还发现小脑蚓部有小脑内血肿（ICH）和左后颅窝急性SDH。入院时的首次脑血管造影检查未发现动脉瘤。然而，为改善她的不良状况，立即进行了急诊手术。进行了脑室引流和急性SDH清除术。术后，她的意识逐渐改善至20P。三周后进行了脑室腹腔分流术。她的意识改善至3P，仅表现出轻微的躯干共济失调。首次手术后两个月，她因康复入住我院。再次进行血管造影，显示左PICA的小脑扁桃体静脉段有一个动脉瘤。通过枕下中线入路成功夹闭了动脉瘤。她的术后病程平稳，目前仍在继续接受康复治疗。与急性SDH相关的后颅窝动脉瘤极为罕见。远端PICA动脉瘤病例仅报道过两例。我们患者的CT扫描不仅显示了蛛网膜下腔出血，还显示了后颅窝的SDH和小脑蚓部的ICH。文献中已描述了100多例远端PICA动脉瘤。我们分析了破裂动脉瘤部位与CT表现之间的关系。位于远端PICA近端部分的动脉瘤主要表现为蛛网膜下腔出血和脑室内出血。另一方面，小脑蚓部和小脑的ICH是位于小脑扁桃体静脉段更远端的破裂动脉瘤的特征性CT表现，在这类动脉瘤病例中占14%。位于小脑扁桃体静脉段更近端部分的动脉瘤未发现ICH和SDH。这些特征性表现与PICA复杂的解剖走行有关。PICA的远端部分走行于小脑蚓部和小脑半球之间，因此如果这些部位的动脉瘤破裂，小脑蚓部和小脑容易发生ICH。在我们这样的病例中，由于有特征性的CT表现，在首次手术时，除了进行脑室引流和清除SDH外，应努力检测远端PICA动脉瘤。还讨论了远端PICA动脉瘤病例的手术方法和预后。
