Wang Yang, Li Guoqing, Hu Xudong, Xu Nanjian, Ma Weihu
Department of Spine Surgery, Ningbo No.6 Hospital Affiliated to Ningbo University, Ningbo, China.
Department of Spine Surgery, Ningbo No.6 Hospital Affiliated to Ningbo University, Ningbo, China.
World Neurosurg. 2024 Dec;192:e423-e434. doi: 10.1016/j.wneu.2024.09.116. Epub 2024 Oct 19.
The prevalence of osteoporotic vertebral fractures has increased with aging populations, necessitating effective treatments such as percutaneous kyphoplasty combined with posterior screw fixation. However, biomechanical research on the effects of using short screws on fixation stability and bone stress or on the impact of bone cement bonding to screws on structural strength is lacking. This study aimed to optimize short-segment fixation strategies for osteoporotic thoracolumbar burst fractures by analyzing the biomechanical effects of pedicle screw length and bone-cement augmentation.
Four models of the thoracolumbar spine were established using computed tomography data of a female volunteer: 1) short screws in the injured vertebra without contact with the bone cement, 2) long screws without contact with the bone cement, 3) long screws in contact with the bone cement, and 4) long screws without the bone cement. The 4 fixation models were simulated under physiological loads. The range of motion, implant stress, and segmental stability were assessed.
The 3 groups containing the bone cement exhibited similar performances in terms of stability and stress distribution, whereas the group without the bone cement exhibited a poorer biomechanical performance. Incorporation of the bone cement enhanced the biomechanical properties of the structure, and short screws in the injured vertebra without contact with the bone cement did not significantly compromise the biomechanical performance.
Short screws in injured vertebrae without contact with the bone cement can achieve satisfactory stability and stress distribution. It is feasible to implant short screws in the injured vertebrae, reduce the number of bilaterally injured vertebrae, and inject bone cement through the non-pedicle approach during the surgical procedure, which simplifies the surgical process.
随着人口老龄化，骨质疏松性椎体骨折的患病率不断上升，因此需要诸如经皮椎体后凸成形术联合后路螺钉固定等有效治疗方法。然而，关于使用短螺钉对固定稳定性和骨应力的影响，或骨水泥与螺钉结合对结构强度的影响的生物力学研究尚属缺乏。本研究旨在通过分析椎弓根螺钉长度和骨水泥强化的生物力学效应，优化骨质疏松性胸腰椎爆裂骨折的短节段固定策略。
利用一名女性志愿者的计算机断层扫描数据建立四个胸腰椎模型：1）伤椎使用短螺钉且不与骨水泥接触；2）使用长螺钉且不与骨水泥接触；3）长螺钉与骨水泥接触；4）长螺钉不使用骨水泥。对这四种固定模型在生理负荷下进行模拟。评估活动范围、植入物应力和节段稳定性。
含骨水泥的三组在稳定性和应力分布方面表现相似，而不含骨水泥的组生物力学性能较差。骨水泥的加入增强了结构的生物力学性能，伤椎中不与骨水泥接触的短螺钉并未显著损害生物力学性能。
伤椎中不与骨水泥接触的短螺钉可实现令人满意的稳定性和应力分布。手术过程中在伤椎植入短螺钉、减少双侧伤椎数量并通过非椎弓根途径注入骨水泥是可行的，这简化了手术过程。
