听神经瘤（VS）通常是表型良性的病变，由于涉及神经血管结构的参与，手术切除可能具有技术挑战性。前下小脑动脉（AICA）通常位于VS附近，与肿瘤之间的位置多变；然而，很少有发表的文献描述了在VS切除中观察到的AICA的解剖和病理变异。我们查询并审查了一个有手术报告和临床/放射学随访资料的前瞻性管理的VS患者队列，并记录了观察到的异常情况。在880个评审患者中，我们发现了66例AICA异常，包括20例延伸到内听道的环路（2.3%），18例植入于硬膜内的动脉（2.0%），15例AICA分支直接位于VS内（1.7%），8例主干动脉穿越第七和第八颅神经之间（0.9%），3例植入颞骨内的动脉（0.2%），1例动脉瘤（0.1%），1例动脉在第六颅神经分叉（0.1%）。AICA变异患者的中位年龄为55岁（范围19-74岁），其中29位为女性（占45%）。与其他AICA变异相比，嵌入AICA的肿瘤在最大轴向直径上往往更大（2.9 vs 1.6 cm；P = .006），它们更常见地进行非完全切除（73% vs 28%；P = .0001），并且术后House-Brackmann分数> 2的比率更高（47% vs 20%；P = .005）。两名患者在术后出现了放射学和症状性脑缺血或出血，其中一例来自骨包裹的AICA，另一例来自植入硬膜的变异体。大约有7%的VS手术中存在AICA的解剖变异。大多数异常情况不影响手术或临床预后，而且主要血管损伤的发生率较低。然而，某些类型的变异可能会增加手术时间，在AICA被肿瘤包裹的情况下，可能表明更具有侵袭性的肿瘤表型，切除率较低，面神经功能障碍的发生率较高。版权所有©2023年神经外科医师大会。保留所有权利。

Vestibular schwannomas (VS) are often phenotypically benign lesions that may be technically challenging to resect because of involvement of neurovascular structures. The anterior inferior cerebellar artery (AICA) is commonly identified near VS, with variable position in relation to the tumor; however, little published literature describes anatomic and pathologic variants of AICA observed during VS resection.A prospectively maintained cohort of surgically managed VS with available operative reports and clinical/radiographic follow-up was queried and reviewed for noted aberrations.We identified 66 cases with noted AICA abnormalities among 880 reviewer cases, including 20 loops extending into the internal auditory canal (2.3%), 18 arteries embedded in dura (2.0%), 15 AICA branches directly within VS (1.7%), 8 main trunk arteries coursing between cranial nerves 7 and 8 (0.9%), 3 arteries embedded in temporal bone (0.2%), 1 aneurysm (0.1%), and 1 artery bifurcating cranial nerve 6 (0.1%). The median age of AICA-variant patients was 55 years (range 19-74), and 29 were female (45%). Compared with the other AICA variants, tumors embedded with AICA tended to be larger lesions on maximal axial diameter (2.9 vs 1.6 cm; P = .006), they more commonly underwent less than total resection (73% vs 28%; P = .0001), and they had higher rates postoperative House-Brackmann scores >2 (47% vs 20%; P = .005). Two patients had radiographic and symptomatic postoperative cerebral ischemia or hemorrhage-1 from a bone-encased AICA and 1 from a dural embedded variant.Anatomic variants of AICA occur in approximately 7% of VS operations. Most aberrations do not affect surgical or clinical outcomes, and the rate of major vascular injury was low. However, certain types variably add operative time and in the case of AICA encasement in the tumor, likely indicate a more aggressive tumor phenotype with lower rates of gross total resection and high incidences of facial nerve weakness.Copyright © Congress of Neurological Surgeons 2023. All rights reserved.