Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, 60 Fenwood Rd, BTM 4th floor, Boston, MA, 02115, USA.
Department of Orthopedics, Xi'an Jiaotong University Second Affiliated Hospital, Xi'an, China.
J Orthop Surg Res. 2020 Jul 29;15(1):291. doi: 10.1186/s13018-020-01812-5.
Interlaminar stabilization and interspinous stabilization are two newer minimally invasive methods for lumbar spine stabilization, used frequently in conjunction with lumbar decompression to treat lumbar stenosis. The two methods share certain similarities, therefore, frequently being categorized together. However, the two methods offer distinct biomechanical properties, which affect their respective effectiveness and surgical success.
To compare the biomechanical characteristics of interlaminar stabilization after lumbar decompression (ILS) and interspinous stabilization after lumbar decompression (ISS). For comparison, lumbar decompression alone (DA) and decompression with instrumented fusion (DF) were also included in the biomechanical analysis.
Four finite element models were constructed, i.e., DA, DF, ISS, and ILS. To minimize device influence and focus on the biomechanical properties of different methods, Coflex device as a model system was placed at different position for the comparison of ISS and ILS. The range of motion (ROM) and disc stress peak at the surgical and adjacent levels were compared among the four surgical constructs. The stress peak of the spinous process, whole device, and device wing was compared between ISS and ILS.
Compared with DA, the ROM and disc stress at the surgical level in ILS or ISS were much lower in extension. The ROM and disc stress at the surgical level in ILS were 1.27° and 0.36 MPa, respectively, and in ISS 1.51°and 0.55 MPa, respectively in extension. This is compared with 4.71° and 1.44 MPa, respectively in DA. ILS (2.06-4.85° and 0.37-0.98 MPa, respectively) or ISS (2.07-4.78° and 0.37-0.98 MPa, respectively) also induced much lower ROM and disc stress at the adjacent levels compared with DF (2.50-7.20° and 0.37-1.20 MPa, respectively). ILS further reduced the ROM and disc stress at the surgical level by 8% and 25%, respectively, compared to ISS. The stress peak of the spinous process in ILS was significantly lower than that in ISS (13.93-101 MPa vs. 31.08-172.5 MPa). In rotation, ILS yielded a much lower stress peak in the instrumentation wing than ISS (128.7 MPa vs. 222.1 MPa).
ILS and ISS partly address the issues of segmental instability in DA and hypermobility and overload at the adjacent levels in DF. ILS achieves greater segmental stability and results in a lower disc stress, compared to ISS. In addition, ILS reduces the risk of spinous process fracture and device failure.
层间稳定和棘突间稳定是两种用于腰椎稳定的新型微创方法，常用于与腰椎减压联合治疗腰椎狭窄症。这两种方法有一定的相似之处，因此经常被归为一类。然而，这两种方法提供了不同的生物力学特性，这影响了它们各自的有效性和手术成功率。
比较腰椎减压后层间稳定（ILS）和腰椎减压后棘突间稳定（ISS）的生物力学特性。为了进行比较，腰椎减压单纯（DA）和减压融合（DF）也被包括在生物力学分析中。
构建了四个有限元模型，即 DA、DF、ISS 和 ILS。为了最小化器械的影响并关注不同方法的生物力学特性，将 Coflex 器械作为模型系统放置在不同的位置，以比较 ISS 和 ILS。比较了四种手术结构在手术和相邻节段的活动范围（ROM）和椎间盘应力峰值。比较了 ISS 和 ILS 棘突、整个器械和器械翼的应力峰值。
与 DA 相比，ILS 或 ISS 在伸展时的 ROM 和手术节段的椎间盘应力要低得多。ILS 的 ROM 和手术节段的椎间盘应力分别为 1.27°和 0.36 MPa，ISS 分别为 1.51°和 0.55 MPa。与 DA 的 4.71°和 1.44 MPa 相比。ILS（分别为 2.06-4.85°和 0.37-0.98 MPa）或 ISS（分别为 2.07-4.78°和 0.37-0.98 MPa）在相邻节段也引起了比 DF（分别为 2.50-7.20°和 0.37-1.20 MPa）更低的 ROM 和椎间盘应力。与 ISS 相比，ILS 进一步降低了手术节段的 ROM 和椎间盘应力分别为 8%和 25%。与 ISS 相比，ILS 的棘突应力峰值明显较低（13.93-101 MPa 与 31.08-172.5 MPa）。在旋转中，ILS 在器械翼上产生的应力峰值明显低于 ISS（128.7 MPa 与 222.1 MPa）。
ILS 和 ISS 部分解决了 DA 中节段不稳定和 DF 中相邻节段过度活动和过载的问题。与 ISS 相比，ILS 实现了更大的节段稳定性，并导致椎间盘应力更低。此外，ILS 降低了棘突骨折和器械失效的风险。
