Lener Sara, Schmölz Werner, Abramovic Anto, Kluger Patrick, Thomé Claudius, Hartmann Sebastian
Department of Neurosurgery, Medical University of Innsbruck, Anichstraße 35, 6020, Innsbruck, Austria.
Department of Orthopedics and Traumatology, Medical University of Innsbruck, Innsbruck, Austria.
Eur Spine J. 2023 Apr;32(4):1358-1366. doi: 10.1007/s00586-023-07587-7. Epub 2023 Feb 24.
Lumbar spinal stenosis is a common disease in the aging population. Decompression surgery represents the treatment standard, however, a risk of segmental destabilization depending on the approach and extent of decompression is discussed. So far, biomechanical studies on techniques were mainly conducted on non-degenerated specimens. This biomechanical in vitro study aimed to investigate the increase in segmental range of motion (ROM) depending on the extent of decompression in degenerated segments.
Ten fresh frozen lumbar specimens were embedded in polymethyl methacrylate (PMMA) and loaded in a spine tester with pure moments of ± 7.5 Nm. The specimens were tested in their intact state for lateral bending (LB), flexion/extension (FE) and axial rotation (AR). Subsequently, four different decompression techniques were performed: unilateral interlaminar decompression (DC1), unilateral with "over the top" decompression (DC2), bilateral interlaminar decompression (DC3) and laminectomy (DC4). The ROM of the index segment was reported as percent (%) of the native state.
Specimens were measured in their intact state prior to decompression. The mean ROM was defined as 100% (FE:6.3 ± 2.3°; LB:5.4 ± 2.8°; AR:3.0 ± 1.6°). Interventions showed a continuous ROM increase: FE (DC1: + 4% ± 4.3; DC2: + 4% ± 4.5; DC3: + 8% ± 8.3;DC4: + 20% ± 15.9), LB(DC1: + 4% ± 6.0; DC2: + 5% ± 7.3; DC3: + 8% ± 8.3; DC4: + 11% ± 9.9), AR (DC1: + 7% ± 6.0; DC2: + 9% ± 7.9; DC3: + 15% ± 11.5; DC4: + 19% ± 10.5). Significant increases in ROM for all motion directions (p < 0.05) were only obtained after complete laminectomy (DC4).
Unilateral and/or bilateral decompressive surgery resulted in a statistically insignificant ROM increase, whereas complete laminectomy showed statistically significant ROM increase. If this ROM increase also has an impact on the clinical outcome and how to identify segments at risk for secondary lumbar instability should be evaluated in further studies.
腰椎管狭窄症是老年人群中的常见疾病。减压手术是治疗的标准方法，然而，根据减压的方式和范围，存在节段性失稳的风险。到目前为止，关于技术的生物力学研究主要在非退变标本上进行。这项生物力学体外研究旨在探讨退变节段减压范围对节段活动度（ROM）增加的影响。
将10个新鲜冷冻的腰椎标本嵌入聚甲基丙烯酸甲酯（PMMA）中，并在脊柱试验机上施加±7.5 Nm的纯力矩。对标本在完整状态下进行侧弯（LB）、屈伸（FE）和轴向旋转（AR）测试。随后，进行四种不同的减压技术：单侧椎板间减压（DC1）、单侧“越过顶部”减压（DC2）、双侧椎板间减压（DC3）和椎板切除术（DC4）。将目标节段的ROM报告为原始状态的百分比（%）。
在减压前对标本的完整状态进行测量。平均ROM定义为100%（FE：6.3±2.3°；LB：5.4±2.8°；AR：3.0±1.6°）。干预后ROM持续增加：FE（DC1：+4%±4.3；DC2：+4%±4.5；DC3：+8%±8.3；DC4：+20%±15.9），LB（DC1：+4%±6.0；DC2：+5%±7.3；DC3：+8%±8.3；DC4：+11%±9.9），AR（DC1：+7%±6.0；DC2：+9%±7.9；DC3：+15%±11.5；DC4：+19%±10.5）。仅在完全椎板切除术后（DC4），所有运动方向的ROM均有显著增加（p<0.05）。
单侧和/或双侧减压手术导致ROM增加，但在统计学上无显著意义，而完全椎板切除术显示ROM有统计学上的显著增加。这种ROM增加是否也会影响临床结果以及如何识别继发性腰椎不稳风险节段，应在进一步研究中进行评估。
