Abstract: Background  There are a variety of nomenclatures and classification systems of paraclinoid aneurysms, most of which have been proposed for neurosurgical purpose . This article aims to develop an improved classification method which can be used during endovascular management on paraclinoid aneurysms and to summarize the main nomenclatures and classification systems of paraclinoid aneurysms. Methods  One hundred and twenty-six patients with 142 saccular paraclinoid aneurysms, who were treated with endovascular embolization in our hospital during January 2009 to December 2011, were tried to be classified as Type Ⅰ(ophthalmic artery aneurysms) and Type Ⅱ(superior hypophyseal artery aneurysms). Each type was further divided into two subtypes according to their relative position to an imaginary bisector that separated ophthalmic artery and posterior communicating artery. Among the four subtypes, Type Ⅰa and Ⅱa referred to aneurysms arising from internal carotid artery (ICA) proximal to the bisector, while Type Ⅰb and Ⅱb referred to aneurysms arising from ICA distal to the bisector. Results  All of the 142 paraclinoid aneurysms were classified successfully. According to our classification system, there were 45 aneurysms belonging to Type Ⅰa, accounting for 31.69% ( 45/142 ), and 11 aneurysms belonging to Type Ⅰb, accounting for 7.75% (11/142 ). Besides, 78 aneurysms were TypeⅡa, accounting for 54.93% (78/142 ), and 8 aneurysms were Type Ⅱb, accounting for 5.63% (8 /142 ). Conclusion  A number of classification systems have been proposed by different groups. It is important to choose suitable classification method in clinical practice, so as to formulate optimal treatment strategy.

Key words: Intracranial aneurysm, Carotid artery, internal, Classification

摘要： 研究背景 颈内动脉床突旁动脉瘤的命名和分类多种多样，大部分为外科手术所用。本文介绍一种适用于血管内治疗的床突旁动脉瘤的改良分类方法，并概述其命名和分类。方法 尝试将126 例患者共142 个床突旁动脉瘤分为两类，即类型Ⅰ（眼动脉动脉瘤）和类型Ⅱ（垂体上动脉动脉瘤）。每一类型再被眼动脉与后交通动脉之间的假想等分线分为两类，其中Ⅰa 和Ⅱa 类动脉瘤主要位于等分线的近心端，Ⅰb 和Ⅱb 类型位于等分线的远心端。结果 全部动脉瘤均获得成功分类，其中Ⅰa 类动脉瘤45个占31.69%（45/142 ），Ⅰb 类动脉瘤11个占7.75%（11/142 ）；Ⅱ a 类动脉瘤78个占54.93%（78/142），Ⅱb 类动脉瘤8 个占5.63%（8/142）。 结论 颈内动脉床突旁动脉瘤分类复杂多样，选择适当的分类方法有利于制定合理的治疗方案。

关键词: 颅内动脉瘤, 颈内动脉, 分类法