Abstract：
BACKGROUND: This study aimed to clarify the quantitative threshold of intraoperative radiological parameters for suspecting posterior malposition of the oblique lumbar interbody fusion (OLIF) cage triggering contralateral radiculopathy.
METHODS: We measured the sagittal center and axial rotation angle (ARA) of the cage using postoperative computed tomography (CT) in 130 patients (215 cages) who underwent OLIF. The location of the cage tip was determined from axial magnetic resonance imaging in selected cases based on CT simulations to assess whether the cage was in contact with the contralateral exiting nerve or whether the surgical instruments could contact the nerve during intradiscal maneuvers.
RESULTS: The sagittal center of the cages was on average 41.5% from the anterior edge of the endplate (shown as AC/AP value: anterior end plate edge-cage center/anterior-posterior endplate edge ×100%), and posterior cage positioning ≥50% occurred in 14% of the cages. The ARA was -2.9°, and posterior oblique rotation of the cages ≥10° (ARA ≤ -10°) was observed in 13%. CT simulation showed that the cage tip could directly contact the contralateral nerve when the cage was placed deep in the posterior portion ≥50% of the AC/AP values with concomitant posterior axial rotation ≥10° (ARA ≤ -10°), or deep in an extremely rare portion ≥60% of the AC/AP values with posterior axial rotation ≥0° (ARA ≤ 0°). Six percent of the cages (13/215) were placed in these posterior oblique areas (potential contact area: PCA). Three cages in the PCA were in direct contact with the contralateral nerves, and 9 were placed deep just anterior to the nerves. Symptomatic contralateral radiculopathy occurred in 2 cages (2/13/215, 15.3%/0.9%).
CONCLUSIONS: Two intraoperative radiological parameters (AC/AP and ARA) measurable during OLIF procedures may become practical indicators for suspecting cage malposition in PCA and may be available when determining whether to consider cage revision intraoperatively to a more ventral disc space or anteriorly from the opposite endplate edge.
METHODS:
METHODS: We measured the sagittal center and axial rotation angle (ARA) of the cage using postoperative computed tomography (CT) in 130 patients (215 cages) who underwent OLIF. The location of the cage tip was determined from axial magnetic resonance imaging in selected cases based on CT simulations to assess whether the cage was in contact with the contralateral exiting nerve or whether the surgical instruments could contact the nerve during intradiscal maneuvers.
RESULTS: The sagittal center of the cages was on average 41.5% from the anterior edge of the endplate (shown as AC/AP value: anterior end plate edge-cage center/anterior-posterior endplate edge ×100%), and posterior cage positioning ≥50% occurred in 14% of the cages. The ARA was -2.9°, and posterior oblique rotation of the cages ≥10° (ARA ≤ -10°) was observed in 13%. CT simulation showed that the cage tip could directly contact the contralateral nerve when the cage was placed deep in the posterior portion ≥50% of the AC/AP values with concomitant posterior axial rotation ≥10° (ARA ≤ -10°), or deep in an extremely rare portion ≥60% of the AC/AP values with posterior axial rotation ≥0° (ARA ≤ 0°). Six percent of the cages (13/215) were placed in these posterior oblique areas (potential contact area: PCA). Three cages in the PCA were in direct contact with the contralateral nerves, and 9 were placed deep just anterior to the nerves. Symptomatic contralateral radiculopathy occurred in 2 cages (2/13/215, 15.3%/0.9%).
CONCLUSIONS: Two intraoperative radiological parameters (AC/AP and ARA) measurable during OLIF procedures may become practical indicators for suspecting cage malposition in PCA and may be available when determining whether to consider cage revision intraoperatively to a more ventral disc space or anteriorly from the opposite endplate edge.
METHODS:
摘要：
背景：本研究旨在阐明术中放射学参数的定量阈值，用于怀疑斜腰椎椎间融合术（OLIF）笼子后错位引发对侧神经根病。
方法：我们使用术后计算机断层扫描（CT）在130例（215个笼子）接受OLIF的患者中测量了笼子的矢状中心和轴向旋转角（ARA）。在选定的病例中，基于CT模拟，从轴向磁共振成像确定笼尖端的位置，以评估笼是否与对侧退出神经接触，或者在椎间盘内操作期间手术器械是否可以接触神经。
结果：笼子的矢状中心距终板前边缘平均为41.5％（显示为AC/AP值：前端板边缘-笼子中心/前后端板边缘×100％），后笼定位≥50％发生在14％的笼子中。ARA为-2.9°,观察到笼子的后斜旋转≥10°（ARA≤-10°）占13％。CT模拟显示，当笼子放置在AC/AP值的后部≥50％，伴随后轴旋转≥10°（ARA≤-10°）时，笼子尖端可以直接接触对侧神经。或深在极罕见部分≥60％的AC/AP值后轴旋转≥0°（ARA≤0°）。6%的笼子(13/215)放置在这些后斜区域(潜在接触面积:PCA)。PCA中的三个笼子与对侧神经直接接触，9个被放置在神经前面的深处。有症状的对侧神经根病发生在2个笼子中（2/13/215，15.3％/0.9％）。
结论：在OLIF手术过程中可测量的两个术中放射学参数（AC/AP和ARA）可能成为怀疑PCA中笼子错位的实用指标，并且在确定是否考虑在术中对更多的腹侧椎间盘间隙或从相对的终板边缘进行笼子翻修时可用。
方法：
方法：我们使用术后计算机断层扫描（CT）在130例（215个笼子）接受OLIF的患者中测量了笼子的矢状中心和轴向旋转角（ARA）。在选定的病例中，基于CT模拟，从轴向磁共振成像确定笼尖端的位置，以评估笼是否与对侧退出神经接触，或者在椎间盘内操作期间手术器械是否可以接触神经。
结果：笼子的矢状中心距终板前边缘平均为41.5％（显示为AC/AP值：前端板边缘-笼子中心/前后端板边缘×100％），后笼定位≥50％发生在14％的笼子中。ARA为-2.9°,观察到笼子的后斜旋转≥10°（ARA≤-10°）占13％。CT模拟显示，当笼子放置在AC/AP值的后部≥50％，伴随后轴旋转≥10°（ARA≤-10°）时，笼子尖端可以直接接触对侧神经。或深在极罕见部分≥60％的AC/AP值后轴旋转≥0°（ARA≤0°）。6%的笼子(13/215)放置在这些后斜区域(潜在接触面积:PCA)。PCA中的三个笼子与对侧神经直接接触，9个被放置在神经前面的深处。有症状的对侧神经根病发生在2个笼子中（2/13/215，15.3％/0.9％）。
结论：在OLIF手术过程中可测量的两个术中放射学参数（AC/AP和ARA）可能成为怀疑PCA中笼子错位的实用指标，并且在确定是否考虑在术中对更多的腹侧椎间盘间隙或从相对的终板边缘进行笼子翻修时可用。
方法：
