Rasmussen Jorge, Plou Pedro, Campero Álvaro, Ajler Pablo
Department of Neurosurgery, Italian Hospital of Buenos Aires, Buenos Aires, Argentina.
Department of Neurosurgery, Padilla Hospital, Tucumán, Argentina.
J Neurol Surg B Skull Base. 2020 Oct;81(5):536-545. doi: 10.1055/s-0039-1692474. Epub 2019 Jun 21.
To hierarchize the anterior inferior cerebellar artery (AICA)-subarcuate artery (SAA) complex's variations in the surgical field. The AICA's "subarcuate loop" (SL) presents multiple variations, closely related to the SAA. AICA-SAA complex's variations may represent major issues in cerebellopontine angle (CPA) surgery. As the spectrum of configurations is originated during the development, a systematized classification was proposed based on the interaction between the petrosal bone and the AICA in the embryonic period. The variations were defined as follow: Grade 0: free, purely cisternal AICA, unidentifiable or absent SAA; Grade 1: purely cisternal AICA, loose SL, SAA > 3 mm; Grade 2: AICA near the subarcuate fossa, pronounced SL, SAA <3 mm; Grade 3: "duralized" AICA, unidentifiable SAA, or included in the petromastoid canal (PMC); and Grade 4: intraosseous AICA, unidentifiable SAA, or included in the PMC. The classification was applied to a series of patients assessed by magnetic resonance constructive interference in steady state sequence. Surgical examples were also provided. Eighty-four patients were evaluated, including 161 CPA. The proportions found in the gradation remained within the range of previous publications (Grade 0: 42.2%; Grade 1: 11.2%; Grade 2: 35.4%; Grade 3: 10.6%; and Grade 4: 0.6%). Moreover, the degrees of the classification were related to the complexity of the anatomical relationships and, therefore, to the difficulty of the maneuvers required to overcome them. The proposed AICA-SAA complex classification allowed to distinguish and objectify pre- and intraoperatively the spectrum of variations, to thoroughly plan the required actions and instrumentation.
对小脑下前动脉（AICA）-弓下动脉（SAA）复合体在手术视野中的变异进行分级。AICA的“弓下襻”（SL）存在多种变异，与SAA密切相关。AICA-SAA复合体的变异可能是桥小脑角（CPA）手术中的主要问题。由于其构型谱在发育过程中形成，基于胚胎期岩骨与AICA之间的相互作用提出了一种系统化分类。变异定义如下：0级：游离的、纯脑池内的AICA，无法识别或不存在SAA；1级：纯脑池内的AICA，松弛的SL，SAA＞3mm；2级：靠近弓下窝的AICA，明显的SL，SAA＜3mm；3级：“硬膜化”的AICA，无法识别的SAA，或包含在岩乳管（PMC）内；4级：骨内AICA，无法识别的SAA，或包含在PMC内。该分类应用于一系列通过磁共振稳态构成干扰序列评估的患者。还提供了手术实例。评估了84例患者，包括161个CPA。分级中发现的比例保持在前文发表范围之内（0级：42.2%；1级：11.2%；2级：35.4%；3级：10.6%；4级：0.6%）。此外，分类的级别与解剖关系的复杂性相关，因此与克服这些关系所需操作的难度相关。所提出的AICA-SAA复合体分类能够在术前和术中区分并客观呈现变异谱，从而全面规划所需的操作和器械。
