van Roden Elizabeth A Rapp, Riggin Corinne N, Holyoak Derek T, Amin Dhara, Hall Patrick, Paredes Juan Jose, Day Cynthia, Rodowicz Kathleen A, Siskey Ryan, Carhart Michael R
Exponent, Inc., 15615 Alton Parkway, Irvine, CA, 92618, USA.
Exponent, Inc., Philadelphia, PA, USA.
Ann Biomed Eng. 2025 Jul 14. doi: 10.1007/s10439-025-03790-3.
Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by "flowing" ossifications that form along the anterolateral aspect of contiguous vertebrae. While prior literature has identified that DISH patients are susceptible to spinal injury, the DISH-specific differences in mechanical response of human spines to applied bending have not been quantified. Therefore, the purpose of this work was to assess the effect of DISH on range of motion, stiffness, and fracture tolerance under flexion/extension loading.
Seven human cadaveric spines were dissected into specimens composed of three functional spinal units (3FSUs), spanning levels T1-T4, T5-T8, and T9-T12. For each 3FSU specimen, the presence of bridging DISH ossification was determined. Ten DISH-affected and eleven normal specimens were evaluated under flexion/extension range of motion followed by extension to failure/system limits.
DISH-affected specimens had significantly less range of motion compared to normal specimens (1.8 deg vs. 3.2 deg, p = 0.0125) and were significantly stiffer (5.5 N·m/deg vs. 2.9 N·m/deg, p = 0.0167). All DISH-affected specimens fractured during extension to failure, whereas five normal specimens did not fracture under the test loading. Hazard ratio analyses indicated that DISH-affected specimens are four times more likely to fracture compared to normal specimens under a given torque and sixteen times more likely for a given extension angle. The normal specimen median energy at fracture was significantly greater than the DISH-affected group (301 Nm·deg vs. 81 Nm·deg, p = 0.006).
This study demonstrates a significant increase in the injury potential of DISH spines during bending loading and provides the first quantitative support for clinical observations of compromised fracture tolerance within the DISH population. Future work classifying the severity of DISH in the context of mechanical response may assist in radiological identification of otherwise asymptomatic patients with increased potential for injury.
弥漫性特发性骨肥厚（DISH）的特征是沿相邻椎体前外侧形成“连续”骨化。虽然先前的文献已经确定DISH患者易发生脊柱损伤，但人类脊柱在施加弯曲时的机械反应中DISH特异性差异尚未量化。因此，本研究的目的是评估DISH对屈伸负荷下运动范围、刚度和骨折耐受性的影响。
将7具人类尸体脊柱解剖成由三个功能脊柱单元（3FSU）组成的标本，跨越T1-T4、T5-T8和T9-T12节段。对于每个3FSU标本，确定是否存在桥接DISH骨化。对10个受DISH影响的标本和11个正常标本进行屈伸运动范围评估，然后伸展至破坏/系统极限。
与正常标本相比，受DISH影响的标本运动范围明显更小（1.8度对3.2度，p = 0.0125），且刚度明显更大（5.5 N·m/度对2.9 N·m/度，p = 0.0167）。所有受DISH影响的标本在伸展至破坏过程中均发生骨折，而5个正常标本在测试负荷下未发生骨折。风险比分析表明，在给定扭矩下，受DISH影响的标本骨折可能性是正常标本的4倍，在给定伸展角度下则为16倍。正常标本骨折时的中位能量明显高于受DISH影响的组（301 Nm·度对81 Nm·度，p = 0.006）。
本研究表明，DISH脊柱在弯曲负荷下的损伤潜力显著增加，并为DISH人群骨折耐受性受损的临床观察提供了首个定量支持。未来在机械反应背景下对DISH严重程度进行分类的工作可能有助于对潜在损伤风险增加的无症状患者进行放射学识别。
