Takata Kenji, Ueda Midori, Takeuchi Kiyotaka, Komiya Hideaki, Yoshikawa Daisuke, Kanai Satomi, Wakabayashi Tasuku, Kitano Ayaki, Toyooka Mariko, Sakai Toyohiko, Tsujikawa Tetsuya
Department of Radiology, Fukui University, Fukui, Japan.
Surg Radiol Anat. 2025 Apr 30;47(1):132. doi: 10.1007/s00276-025-03640-w.
The vertebral artery (VA) typically enters the subarachnoid space at the atlanto-occipital region. However, segmental variations can occur, with the VA entering the spinal canal at atypical levels. While a C3 segmental VA has been reported, no prior studies describe a C5 segmental VA. This case represents the first documented occurrence of this anomaly.
An 8-year-old girl underwent brain magnetic resonance imaging for headache screening, which incidentally revealed an abnormal VA course.
Imaging revealed the absence of the left VA at the proximal V2 segment. Instead, a radiculomedullary artery at C4/5 entered the spinal canal and contributed to the formation of the anterior spinal artery (ASA), which ascended along the spinal cord. The right VA appeared normal; however, a radiculomedullary artery at the C3/4 level was identified, joining the contralateral radiculomedullary artery at the C1 level to form the ASA. Additionally, bilateral accessory middle cerebral arteries were observed. No clear association was found between this anomaly and the patient's headache, and she remained under observation.
This anomaly may result from persistence of the fifth intersegmental artery. The vascular course resembled collateral circulation observed in acquired VA occlusion. Given its proximity to the spinal cord, potential risks include ischemic complications and spinal cord compression. This case highlights the importance of accurate imaging and careful surgical planning. Further studies on these rare vascular anomalies will enhance our understanding of VA variations and their clinical significance.
椎动脉（VA）通常在枕骨大孔区进入蛛网膜下腔。然而，可能会出现节段性变异，椎动脉在非典型水平进入椎管。虽然已有报道C3节段性椎动脉，但此前尚无研究描述C5节段性椎动脉。本病例是该异常情况的首次文献记载。
一名8岁女孩因头痛筛查接受脑部磁共振成像检查，偶然发现椎动脉走行异常。
影像学检查显示左侧椎动脉近端V2段缺如。取而代之的是，一条C4/5水平的神经根髓动脉进入椎管，并参与形成沿脊髓上升的脊髓前动脉（ASA）。右侧椎动脉外观正常；然而，在C3/4水平发现一条神经根髓动脉，它在C1水平与对侧神经根髓动脉汇合形成脊髓前动脉。此外，还观察到双侧大脑中动脉副支。未发现该异常与患者头痛之间有明确关联，患者仍在观察中。
这种异常可能是由于第五节段间动脉持续存在所致。其血管走行类似于在获得性椎动脉闭塞中观察到的侧支循环。鉴于其靠近脊髓，潜在风险包括缺血性并发症和脊髓压迫。本病例强调了准确成像和仔细手术规划的重要性。对这些罕见血管异常的进一步研究将增进我们对椎动脉变异及其临床意义的理解。
