Biomedical Department, AO Research Institute Davos, Davos, Switzerland.
Department of Spine Surgery, Schulthess Clinic, Zurich, Switzerland.
Eur Spine J. 2024 Sep;33(9):3443-3451. doi: 10.1007/s00586-024-08391-7. Epub 2024 Jul 17.
Screwed anterior lumbar interbody fusion (SALIF) alleviates the need for supplemental posterior fixation leading to reduction of perioperative morbidity. Specifically, elderly and multimorbid patients would benefit from shorter operative time and faster recovery but tend to have low bone mineral density (BMD). The current study aimed to compare loosening, defined as increase of ROM and NZ, of SALIF versus transforaminal lumbar interbody fusion (TLIF) under cyclic loading in cadaveric spines with reduced BMD.
Twelve human spines (L4-S2; 6 male 6 female donors; age 70.6 ± 19.6; trabecular BMD of L5 84.2 ± 24.4 mgHA/cm, range 51-119 mgHA/cm) were assigned to two groups. SALIF or TLIF were instrumented at L5/S1. Range of motion (ROM) and neutral zone (NZ) were assessed before and after axial cyclic loading (0-1150 N, 2000 cycles, 0.5 Hz) in flexion-extension (Flex-Ext), lateral bending, (LB), axial rotation (AR).
ROM of the SALIF specimens increased significantly in all loading directions (p ≤ 0.041), except for left AR (p = 0.053), whereas for TLIF it increased significantly in left LB (p = 0.033) and Flex (p = 0.015). NZ of SALIF showed increase in Flex-Ext and LB, whereas NZ of TLIF did not increase significantly in any motion direction.
Axial compression loading caused loosening of SALIF in Flex-Ext and LB, but not TLIF at L5/S1 in low BMD specimens. Nevertheless, Post-cyclic ROM and NZ of SALIF is comparable to TLIF. This suggests that, neither construct is optimal for the use in patients with reduced BMD.
经前路螺钉腰椎间融合术（SALIF）可减轻对辅助后路固定的需求，从而降低围手术期发病率。具体而言，老年和多病患者将从更短的手术时间和更快的康复中受益，但他们往往存在骨密度（BMD）较低的问题。本研究旨在比较在 BMD 降低的尸体脊柱中，在循环加载下 SALIF 与经椎间孔腰椎间融合术（TLIF）的松动情况，定义为 ROM 和 NZ 的增加。
将 12 个人体脊柱（L4-S2；6 名男性，6 名女性供体；年龄 70.6±19.6 岁；L5 的小梁骨密度为 84.2±24.4 mgHA/cm，范围为 51-119 mgHA/cm）分为两组。在 L5/S1 处对 SALIF 或 TLIF 进行仪器操作。在屈伸（Flex-Ext）、侧屈（LB）、轴向旋转（AR）方向进行轴向循环加载（0-1150 N，2000 个循环，0.5 Hz）前后，评估运动范围（ROM）和中立区（NZ）。
SALIF 标本的 ROM 在所有加载方向上均显著增加（p≤0.041），除了左侧 AR（p=0.053）外，而 TLIF 的左侧 LB（p=0.033）和 Flex（p=0.015）的 ROM 显著增加。SALIF 的 NZ 在 Flex-Ext 和 LB 中增加，而 TLIF 的 NZ 在任何运动方向上均无显著增加。
在低 BMD 标本中，轴向压缩载荷导致 SALIF 在 Flex-Ext 和 LB 中的松动，但 TLIF 在 L5/S1 中没有松动。然而，SALIF 的循环后 ROM 和 NZ 与 TLIF 相当。这表明，这两种结构都不是 BMD 降低患者的最佳选择。
