Departments of1Neurosurgery and.
2Orthopedics and Rehabilitation, The University of Iowa Hospitals and Clinics; and.
J Neurosurg Spine. 2022 Jul 8;37(6):836-842. doi: 10.3171/2022.5.SPINE22371. Print 2022 Dec 1.
Adjacent-segment disease (ASD) proximal to lumbosacral fusion is assumed to result from increased stress and motion that extends above or below the fusion construct. Sublaminar bands (SBs) have been shown to potentially mitigate stresses in deformity constructs. A similar application of SBs in lumbar fusions is not well described yet may potentially mitigate against ASD.
Eight fresh-frozen human cadaveric spine specimens were instrumented with transforaminal lumbar interbody fusion (TLIF) cages at L3-4 and L4-5, and pedicle screws from L3 to S1. Bilateral SBs were applied at L2 and tightened around the rods extending above the L3 pedicle screws. After being mounted on a testing frame, the spines were loaded at L1 to 6 Nm in all 3 planes, i.e., flexion/extension, right and left lateral bending, and right and left axial rotation. Motion and intradiscal pressures (IDPs) at L2-3 were measured for 5 conditions: intact, instrumentation (L3-S1), band tension (BT) 30%, BT 50%, and BT 100%.
There was significant increase in motion at L2-3 with L3-S1 instrumentation compared with the intact spine in flexion/extension (median 8.78°, range 4.07°-10.81°, vs median 7.27°, range 1.63°-9.66°; p = 0.016). When compared with instrumentation, BT 100% reduced motion at L2-3 in flexion/extension (median 8.78°, range 4.07°-10.81°, vs median 3.61°, range 1.11°-9.39°; p < 0.001) and lateral bending (median 6.58°, range 3.67°-8.59°, vs median 5.62°, range 3.28°-6.74°; p = 0.001). BT 50% reduced motion at L2-3 only in flexion/extension when compared with instrumentation (median 8.78°, range 4.07°-10.81°, vs median 5.91°, range 2.54°-10.59°; p = 0.027). There was no significant increase of motion at L1-2 with banding when compared with instrumentation, although an increase was seen from the intact spine with BT 100% in flexion/extension (median 5.14°, range 2.47°-9.73°, vs median 7.34°, range 4.22°-9.89°; p = 0.005). BT 100% significantly reduced IDP at L2-3 from 25.07 psi (range 2.41-48.08 psi) before tensioning to 19.46 psi (range -2.35 to 29.55 psi) after tensioning (p = 0.016).
In this model, the addition of L2 SBs reduced motion and IDP at L2-3 after the L3-S1 instrumentation. There was no significant increase in motion at L1-2 in response to band tensioning compared with instrumentation alone. The application of SBs may have a clinical application in reducing the incidence of ASD.
邻近节段疾病（ASD）靠近腰骶融合，被认为是由于融合结构上方或下方的应力和运动增加所致。已经表明，板层带（SBs）有可能减轻畸形结构中的应力。在腰椎融合中类似地应用 SBs 尚未得到很好的描述，但可能潜在地减轻 ASD 的发生。
对 8 个新鲜冷冻的人体尸体脊柱标本进行经椎间孔腰椎体间融合（TLIF）笼在 L3-4 和 L4-5 处的置备，并在 L3 至 S1 处使用椎弓根螺钉。在 L2 处施加双侧 SBs 并在延伸至 L3 椎弓根螺钉上方的杆周围收紧。在安装在测试框架上后，脊柱在所有 3 个平面（屈伸、左右侧弯曲和左右轴向旋转）以 1 至 6 Nm 的力加载。在 5 种情况下测量 L2-3 的运动和椎间盘内压（IDP）：完整、器械（L3-S1）、带张力（BT）30%、BT 50%和 BT 100%。
与完整脊柱相比，L3-S1 器械置入时 L2-3 的运动明显增加（中位值 8.78°，范围 4.07°-10.81°，与中位值 7.27°，范围 1.63°-9.66°相比；p = 0.016）。与器械相比，BT 100%在屈伸时减少了 L2-3 的运动（中位值 8.78°，范围 4.07°-10.81°，与中位值 3.61°，范围 1.11°-9.39°相比；p < 0.001）和侧弯曲（中位值 6.58°，范围 3.67°-8.59°，与中位值 5.62°，范围 3.28°-6.74°相比；p = 0.001）。与器械相比，BT 50%仅在屈伸时减少了 L2-3 的运动（中位值 8.78°，范围 4.07°-10.81°，与中位值 5.91°，范围 2.54°-10.59°相比；p = 0.027）。与器械相比，带扎时 L1-2 的运动没有明显增加，尽管在 BT 100%下从完整脊柱开始时，屈伸时的运动增加（中位值 5.14°，范围 2.47°-9.73°，与中位值 7.34°，范围 4.22°-9.89°相比；p = 0.005）。BT 100%显著降低了 L2-3 的 IDP，从紧张前的 25.07 psi（范围 2.41-48.08 psi）降至紧张后的 19.46 psi（范围-2.35 至 29.55 psi）（p = 0.016）。
在该模型中，L2 的 SBs 的添加减少了 L3-S1 器械置入后的 L2-3 运动和 IDP。与单独使用器械相比，在 L1-2 处没有明显增加的运动响应。SBs 的应用可能在降低 ASD 的发生率方面具有临床应用。
