1Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois.
2Department of Orthopedic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
J Neurosurg Spine. 2023 May 5;39(2):254-262. doi: 10.3171/2023.4.SPINE221283. Print 2023 Aug 1.
Anterior lumbar interbody fusion (ALIF) is a well-accepted surgical technique used to treat various lumbar degenerative pathologies. Recently, hyperlordotic cages have been introduced to create higher degrees of lordosis to the lumbar spine. There are little data currently available to define the radiographic benefits that these cages provide with stand-alone ALIF. The goal of the present study was to assess the effect of increasing cage angles on postoperative subsidence, sagittal alignment, and foraminal and disc height in patients who underwent single-level stand-alone ALIF surgery.
A retrospective cohort study was performed of consecutive patients who underwent single-level ALIF by a single spine surgeon. Radiographic analysis included global lordosis, operative level of segmental lordosis, cage subsidence, sacral slope, pelvic tilt, pelvic incidence, pelvic incidence-lumbar lordosis mismatch, edge loading, foraminal height, posterior disc height, anterior disc height, and adjacent-level lordosis. Multivariate linear and logistic regressions were performed to analyze the relationship between cage angle and radiographic outcomes.
Seventy-two patients were included in the study and divided into three groups based on cage angle: < 10° (n = 17), 10°-15° (n = 36), and > 15° (n = 19). Within the entire study cohort, there were significant improvements in disc and foraminal height, as well as segmental and global lordosis, at the final follow-up after single-level ALIF. However, when stratified by cage angle groups, patients with > 15° cages did not have any additional significant changes in global or segmental lordosis compared with those patients with smaller cage angles, but patients with > 15° cages showed greater risk of subsidence while also having significantly less improvements in foraminal height, posterior disc height, and average disc height compared with the other groups.
Patients with < 15° stand-alone ALIF cages showed improved average foraminal and disc (posterior, anterior, and average) height without sacrificing improvements in sagittal parameters or increasing risk of subsidence when compared to patients with hyperlordotic cages. The use of hyperlordotic cages > 15° did not provide spinal lordosis commensurate with the lordotic angle of the cage and had a greater risk of subsidence. Although this study was limited by a lack of patient-reported outcomes to correlate with radiographic results, these findings support the judicious use of hyperlordotic cages in stand-alone ALIF.
前路腰椎间融合术（ALIF）是一种广泛应用于治疗各种腰椎退行性病变的手术技术。最近，出现了高位椎间融合器，用于增加腰椎的前凸角度。目前，关于单独使用 ALIF 时这些融合器在影像学方面的益处的数据很少。本研究的目的是评估在接受单节段独立 ALIF 手术的患者中，增加融合器角度对术后下沉、矢状位平衡和椎间孔及椎间盘高度的影响。
对单名脊柱外科医生进行的单节段 ALIF 的连续患者进行回顾性队列研究。影像学分析包括总体前凸角度、手术节段前凸角度、融合器下沉、骶骨倾斜角、骨盆倾斜角、骨盆入射角、骨盆入射角-腰椎前凸角不匹配、边缘负荷、椎间孔高度、椎间盘后高度、椎间盘前高度和临近节段前凸角度。进行多元线性和逻辑回归分析，以分析融合器角度与影像学结果之间的关系。
本研究共纳入 72 例患者，根据融合器角度分为三组：<10°（n=17）、10°-15°（n=36）和>15°（n=19）。在整个研究队列中，在单节段 ALIF 后的最终随访时，椎间盘和椎间孔高度以及节段和总体前凸角度均有显著改善。然而，按融合器角度分组时，与角度较小的融合器相比，角度>15°的融合器在整体或节段前凸角度上没有任何显著的变化，但角度>15°的融合器下沉风险更大，椎间孔高度、椎间盘后高度和平均椎间盘高度的改善也明显减少。
与使用高位椎间融合器（>15°）的患者相比，使用<15°的独立 ALIF 融合器的患者在改善平均椎间孔和椎间盘（后、前、平均）高度的同时，不会牺牲矢状位参数的改善或增加下沉的风险。使用>15°的高位椎间融合器并没有提供与融合器前凸角度相称的脊柱前凸角度，而且下沉的风险更大。尽管本研究由于缺乏与影像学结果相关的患者报告结局而受到限制，但这些发现支持在独立 ALIF 中谨慎使用高位椎间融合器。
