Objectives The abducens nerve has a long, serpentine subarachnoid course with complex topographical relationships, rendering abducens nerve palsy the most common ocular motor cranial nerve palsy in adults and second most common in pediatric patients, with anatomical variants reported in the literature. Preoperative awareness of abducens nerve variant anatomy may help prevent inadvertent intraoperative injury. Design This study is a case report with a review of the abducens nerve anatomy and variants. Setting The study setting included outpatient, inpatient, and operating room in the neurosurgery department of a quaternary referral center. Participants The study included a woman in her early 30s with a diagnosis of petrous meningioma. Main Outcome Measures In vivo documentation of a type 3 abducens nerve duplication was carried out. Results A left extended retrosigmoid craniotomy was recommended for the petroclival meningioma resection. Intraoperatively, a complete duplication of the left abducens cisternal segment was encountered and photographed. The left unilateral abducens nerve duplication was confirmed with postoperative volumetric magnetic resonance imaging using the FIESTA (fast imaging employing steady-state acquisition) sequence, revealing the union of the duplicated cisternal abducens nerves into a single trunk from Dorello's canal distally. Conclusions Abducens nerve variants are uncommon, and although reported in the setting of cadaveric dissection, in vivo documentation of them is limited. This case report of an in vivo type 3 abducens nerve duplication with intraoperative photographic and radiographic images highlights the need for clinical awareness to avoid inadvertent intraoperative injury.

中文翻译：

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外展神经重复：罕见解剖变异的新颖术中和放射学观察

目的 外展神经具有较长的蛇形蛛网膜下腔走行，具有复杂的地形关系，使得外展神经麻痹成为成人最常见的眼运动颅神经麻痹，在儿童患者中排名第二，其解剖变异在文献中有所报道。术前了解外展神经变异解剖结构可能有助于防止术中意外损伤。设计 本研究是一份病例报告，回顾了外展神经的解剖结构和变异。研究环境 研究环境包括四级转诊中心神经外科的门诊、住院和手术室。参与者 该研究包括一名 30 岁出头、被诊断患有岩部脑膜瘤的女性。主要结果测量 进行了 3 型外展神经复制的体内记录。结果岩斜区脑膜瘤切除术推荐采用左侧扩大乙状结肠后开颅手术。术中，发现左外展肌池段完全重复并​​拍照。术后使用FIESTA（采用稳态采集的快速成像）序列的体积磁共振成像证实了左侧单侧外展神经重复，揭示了重复的脑池外展神经在远端从多雷洛管连接成单个主干。结论 外展神经变异并不常见，尽管在尸体解剖中有所报道，但其体内记录有限。这份关于体内 3 型外展神经复制的病例报告以及术中摄影和放射线图像强调了临床意识的必要性，以避免意外的术中损伤。