Department of Orthopedics, Lianyungang Hospital of Traditional Chinese Medicine, Lianyungang, Jiangsu, People's Republic of China.
Department of Orthopedics, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, Jiangsu, People's Republic of China.
J Orthop Surg Res. 2023 May 19;18(1):371. doi: 10.1186/s13018-023-03838-x.
Adjacent segment disease (ASD) is a commonly reported complication after lumbar interbody fusion (LIF); changes in the mechanical environment play an essential role in the generation of ASD. Traditionally, fixation-induced high stiffness in the surgical segment was the main reason for ASD. However, with more attention paid to the biomechanical significance of posterior bony and soft structures, surgeons hypothesize that this factor may also play an important role in ASD.
Oblique and posterior LIF operations have been simulated in this study. The stand-alone OLIF and OLIF fixed by bilateral pedicle screw (BPS) system have been simulated. The spinal process (the attachment point of cranial ligamentum complex) was excised in the PLIF model; the BPS system has also been used in the PLIF model. Stress values related to ASD have been computed under physiological body positions, including flexion, extension, bending, and axial rotations.
Compared to the stand-alone OLIF model, the OLIF model with BPS fixation suffers higher stress values under extension body position. However, there are no apparent differences under other loading conditions. Moreover, significant increases in stress values can be recorded in flexion and extension loading conditions in the PLIF model with posterior structures damage.
Fixation-induced surgical segment's high stiffness and the damage of posterior soft tissues together trigger a higher risk of ASD in patients with LIF operations. Optimizing BPS fixation methods and pedicle screw designs and reducing the range of posterior structures excision may be an effective method to reduce the risk of ASD.
邻近节段疾病（ASD）是腰椎体间融合（LIF）后常见的并发症；力学环境的改变在 ASD 的发生中起着至关重要的作用。传统上，手术节段固定引起的高刚度是 ASD 的主要原因。然而，随着人们越来越关注后方骨与软组织的生物力学意义，外科医生假设这一因素也可能在 ASD 中起重要作用。
本研究模拟了斜向和后路 LIF 手术。模拟了单纯 OLIF 和双侧椎弓根螺钉（BPS）系统固定的 OLIF 固定。PLIF 模型中切除了脊柱突（颅韧带复合体的附着点）；PLIF 模型中也使用了 BPS 系统。在生理体位下（包括屈伸、侧弯和轴向旋转）计算了与 ASD 相关的应力值。
与单纯 OLIF 模型相比，BPS 固定的 OLIF 模型在伸展体位下承受更高的应力值。然而，在其他加载条件下没有明显差异。此外，在损伤后方软组织的 PLIF 模型中，屈伸加载条件下的应力值显著增加。
固定引起的手术节段高刚度和后方软组织的损伤共同增加了 LIF 术后 ASD 的风险。优化 BPS 固定方法和椎弓根螺钉设计，减少后方结构切除范围，可能是降低 ASD 风险的有效方法。
