Department of Spine Surgery, Zhengzhou Orthopaedics Hospital, 58 Longhai Middle Road, Zhengzhou City, Henan Province, China.
Fudan University Shanghai Cancer Center, 270 Dong'an Road, Xuhui District, Shanghai, China.
BMC Musculoskelet Disord. 2020 Feb 15;21(1):104. doi: 10.1186/s12891-020-3128-5.
Previous studies have revealed positive effect of Topping-off technique on upper adjacent segment after fusion surgery, while for the cases with fusion surgery on L5-S1 segment, owning maximal range of motion, and preexisting degenerated upper adjacent disc, it is necessary to clarify the superiority of Topping-ff technique and the effect exerted on the lumbar spine.
A young healthy male volunteer was selected for thin-slice CT scanning. Then the image information was imported into the computer to establish the whole lumbar spine model as the health model. The medium degeneration model of intervertebral disc was established by changing the material properties of L4-S1 disc on the basis of the health model, and the fusion model and Topping-off model were respectively established on the basis of the degenerated model. The variation trend of ROM of L2-L5 and the stress changes of L4-L5 intervertebral disc, nucleus pulposus and facet joints were calculated respectively.
The L4-L5 ROM of fusion model increased significantly but the ROM of L2-L3 and L3-L4 segments did not change significantly. Compared with the degenerated model, L4-L5 activity of the Topping-off model decreased, and ROM of the L2-L3 and L3-L4 increased to some extent in the flexion and extension positions. The stress on the disc, nucleus pulposus and facet joint of the fusion model L4-L5 increased in four positions of flexion, extension, rotation and bending compared with the degenerated model, while the fiber stress on the Topping-off model decreased significantly in all four positions.
Topping-off technology can decrease the stress and ROM of the adjacent upper degenerated segment, and increase the ROM of other upper segments, thereby protecting the degenerated upper adjacent segments and compensating the lumbar spine mobility.
既往研究表明，终板成形术对融合术后上位邻近节段具有积极影响，而对于融合术在 L5-S1 节段的病例，由于运动范围最大且存在预先退变的上位邻近椎间盘，有必要明确终板成形术的优势及其对腰椎的影响。
选择一名年轻健康男性志愿者进行薄层 CT 扫描。然后将图像信息导入计算机，建立整个腰椎模型作为健康模型。在健康模型的基础上，通过改变 L4-S1 椎间盘的材料特性，建立椎间盘中度退变模型，并在此基础上建立融合模型和终板成形模型。分别计算 L2-L5 的 ROM 变化趋势和 L4-L5 椎间盘、核髓和关节突关节的应力变化。
融合模型的 L4-L5 ROM 显著增加，但 L2-L3 和 L3-L4 节段的 ROM 没有明显变化。与退变模型相比，终板成形模型的 L4-L5 活动减少，屈伸位 L2-L3 和 L3-L4 的 ROM 有所增加。与退变模型相比，融合模型 L4-L5 椎间盘、核髓和关节突关节在屈伸、旋转和弯曲四个位置的受力增加，而终板成形模型的纤维受力在四个位置均显著降低。
终板成形技术可以降低上位邻近退变节段的应力和 ROM，增加其他上位节段的 ROM，从而保护上位邻近退变节段，补偿腰椎活动度。
