目的    通过MRI研究Ⅰ~II度腰椎滑脱对腰椎左侧节段血管及OLIF手术通道安全区的影响。  方法    回顾2019年10月~2022年11月收治的221例符合选择标准的腰腿痛患者腰椎MRI资料，将椎间隙高度无明显塌陷且椎体间无移位的腰椎间盘突出、椎间盘源性腰痛、退行性腰椎管狭窄症患者归为对照组（n=107），Ⅰ~II度腰椎滑脱的患者归为观察组（n=114）。测量并比较左侧椎体侧方节段血管发出角度、血管走行角度、血管长度、椎体不同Moro区域节段血管间距及其与相邻椎间盘边缘的距离，分析血管间面积和22 mm模拟通道内出现血管比例的差异。  结果    ①与对照组相比，观察组L4血管发出角度、L1/L3/L4/L5血管走行角度、L2/L4血管长度均减小；在II~III、III~IV区交界，L1,2、L3,4节段血管间距减小，二者血管间面积也相应减小。②两组L4,5椎体节段血管间距在III~IV区交界均<22 mm，除L3~5在I~II区交界节段血管尾侧与同序列椎体下缘的距离>10 mm外，两组患者其它部位节段血管与同序列椎体上/下缘的距离均<10 mm。节段血管与同序列椎体下缘距离：观察组L1 II~IV区交界的距离减小，L4 II~IV区交界的距离增大；节段血管与同序列椎体上缘距离：观察组L2 I~II区交界、L2~5 II~III区交界、L2/L4 III~IV区交界的距离减小。③观察组模拟通道内发现血管的比例大于对照组，其中以L4,5 I区、II区发现L5节段血管的差异最显著。  结论    I~II度腰椎滑脱影响腰椎左侧节段血管的走形，缩小L1,2、L3,4节段血管间距，缩小II~III区交界L2~L5节段血管至同序列椎体上缘的距离，增加了OLIF通道建立的难度和风险。尤其是在L4,5间隙进行操作时，需避免在距椎间盘边缘10 mm的椎体及III~IV区交界放置OLIF扩张通道，可适当将通道向II区头侧调整，密切注意L5节段血管在I区、II区的走形分布以避免损伤。

Objective    To study the effects of Ⅰ~Ⅱ degree lumbar spondylolisthesis on the left lumbar segmental vessels  and the safety zone of OLIF surgical access by MRI.    Methods    The MRI data of lumbar spine of 221 patients with low back and leg pain who met the selection criteria from October 2019 to November 2022 were retrospectively analyzed, and patients with lumbar disc herniation, discogenic low back pain, and degenerative lumbar spinal stenosis without significant collapse of the intervertebral space height and without intervertebral displacement were divided into the control groups (n=107). Patients with I～II degree lumbar spondylolisthesis  were divided into the observation group (n=114). The angles of vascular emanation from the lateral segments of the left vertebral , the angles of vascular travel, the length of the vessels, the spacing of the vessels in the segments of different Moro regions of the vertebral and their distance from the adjacent disc edges were measured and compared between the two groups. The differences in the area between segmental vessels and the proportion of vessels present in the simulated channels were also analyzed.     Results     ① Compared with the control group, the angle of L4 vessel emanation, the angle of L1/L3/L4/L5 vessel travel, and the length of L2/L4 vessels were reduced in the observation group, and the distance between the vessels of L1,2 and L3,4 segments was decreased at the junction of II-III and III -IV zones, and the intervascular area was reduced accordingly. ②The area between the L4,5 vertebral segmental vessels was<22mm at the junction of the III-IV region in  both groups .The distance between the segmental vessels and the edge of the same sequence of vertebral bodies is<10 mm in the two groups,except the distance between the L3-5 vessels with the same sequence of lower edge in the I-II region. In addition, the results of the same sequence of vertebral artery distances from the lower edge of the vertebral suggested that the distances at the junction of L1 II - IV zones decreased, but the distances at the junction of L4 II - IV zones increased, while the results of the same sequence of vertebral vein distances from the upper edge of the vertebral suggested that the distances at the junction of L2 I - II zones, L2-5 II - III zones, and L2/L4 III - IV zones decreased. ③ The proportion of lumbar segmental vessels in the simulated channels was greater in the observation group than in the control group, with the most significant differences found in the L5 vessels in zones I and II.    Conclusions    Ⅰ～Ⅱ degree lumbar spondylolisthesis affect the travel of the left lumbar segmental vessels, reduce the distance between segmental vessels in L1,2 and L3,4 , narrow the distance from the L2-5 segmental vessels at the junction of zones II-III to the upper edge of the vertebral in the same sequence, increase the difficulty and risk of OLIF channel establishment. In particular, when operating in the L4,5 interval, it is necessary to avoid placing OLIF expansion channels at 10 mm from the disc edge and at the junction of zone III-IV. The channels can be adjusted to the cephalic side of zone II as appropriate, and close attention should be paid to the alignment and distribution of the vessels of the L5 segment in zones I and II to avoid injury.