van Heeswijk Vonne Maria, Robertson Peter Alexander, Thambyah Ashvin, Broom Neil David
Experimental Tissue Mechanics Laboratory, Department of Chemical and Materials Engineering, University of Auckland, Auckland, New Zealand.
The Orthopaedic Clinic, Mercy Specialist Centre, Auckland, New Zealand.
Eur Spine J. 2025 May 3. doi: 10.1007/s00586-025-08888-9.
To (a) investigate patterns of structural damage in flexed, healthy ovine lumbar motion segments subjected to controlled impact loading approximating a low energy traumatic fall; and (b) determine the relative risk of herniation, endplate failure and other subtle modes of structural disruption as potential mechanical initiators of disc degeneration.
Twenty-three healthy ovine lumbar motion segments were flexed 7° and then impact loaded by dropping a weight of 4.3 kg from a height of 0.8 m. Each sample was macroscopically assessed externally for herniations and then sagittally bisected to assess internal structural damage.
Fifteen segments suffered endplate failure, 7 herniated, and 1 suffered both an endplate fracture and herniation. Thirteen segments had a major fracture of the superior endplate and 8 of these also contained subtle damage in the anterior annulus and/or inferior vertebra. Overall, both herniated and endplate fractured samples indicated an oblique mode of failure tending from posterior-superior to anterior-inferior. Other forms of subtle tissue damage were observed across all visible regions of the disc, these coexisting with the major modes of failure.
Flexed ovine lumbar motion segments subjected to impact loading approximating a low energy traumatic fall, are more likely to fail via endplate fracture accompanied by more subtle structural damage in the disc and/or adjacent vertebra. Failure by disc herniation was less common. The subtle, co-occurring, multi-component failure modes add to our recognition of the complexity of these injuries, and the potential role they might play in the initiation and development of the degenerative cascade in the intervertebral disc.
(a) 研究在模拟低能量创伤性跌倒的可控冲击载荷作用下，处于屈曲状态的健康绵羊腰椎运动节段的结构损伤模式；(b) 确定椎间盘突出、终板失效及其他细微结构破坏模式作为椎间盘退变潜在机械引发因素的相对风险。
将23个健康绵羊腰椎运动节段屈曲7°，然后从0.8米高度掉落4.3千克重物进行冲击加载。对每个样本进行外部宏观评估以检查是否有椎间盘突出，然后沿矢状面平分以评估内部结构损伤。
15个节段发生终板失效，7个节段发生椎间盘突出，1个节段同时发生终板骨折和椎间盘突出。13个节段发生上位终板的主要骨折，其中8个节段在前侧纤维环和/或下位椎体中也存在细微损伤。总体而言，椎间盘突出和终板骨折的样本均显示出从后上至前下的斜向失效模式。在椎间盘的所有可见区域均观察到其他形式的细微组织损伤，这些损伤与主要失效模式并存。
在模拟低能量创伤性跌倒的冲击载荷作用下，处于屈曲状态的绵羊腰椎运动节段更有可能通过终板骨折而失效，同时椎间盘和/或相邻椎体存在更细微的结构损伤。椎间盘突出导致的失效较少见。这些细微的、同时发生的、多组分的失效模式增加了我们对这些损伤复杂性的认识，以及它们在椎间盘退变级联反应的起始和发展中可能发挥的潜在作用。
