OBJECTIVE To investigate the relationship between different types of laminectomy extension and spinal cord injury subsequent to acute spinal shorting after 3-column osteotomy in living goat model. METHODS A total of 18 healthy goats were selected, and a procedure of bivertebral column resections and total laminectomy of T13 and L1 was completed followed by different laminectomy extensions under the somatosensory evoked potential (SSEP) monitoring. The samples were divided into three groups according to types of subsequent laminectomy extension. In the first group (enlarged resection of upper lamina group), laminectomy extension was performed on 10 mm caudal to T12; in the second group (equidistant enlarged resection of upper and lower lamina group), laminectomy extension was performed on 5 mm caudal to T12 and 5 mm cranial to L2 simultaneously; and in the third group (enlarged resection of lower lamina group), laminectomy extension was performed on 10 mm cranial to L2. The SSEP measured after vertebral resection was set as the baseline, and the SSEP decreased by 50% from the baseline amplitude and/or delayed by 10% relative to the baseline peak latency was set as positive results, which indicated spinal cord injury. Spinal column was gradually shortened until the SSEP monitoring just did not show a positive result. The shortened distance (ΔH) and the changed angle of the spinal cord buckling (Δα) were measured in each group. Neurologic function was recorded by the Tarlov scores at 2 days after the surgery. RESULTS The safe shortening distances of three groups were 38.6 ± 1.2 mm, 41.5 ± 0.7 mm, 43.7 ± 0.8 mm, respectively; the corresponding changed angles of the spinal cord buckling were 62.8 ± 6.9°, 82.8 ± 7.5°, and 98.5 ± 7.0°. Significant differences of ΔH and Δα were found among the three groups by LSD multiple comparison test (P < 0.05). Strong correlation between ΔH and Δα was shown in each group by Pearson's correlation test. CONCLUSIONS Different laminectomy extensions after 3-column osteotomy have different effects on the prevention of SCI caused by acute spinal shortening. The enlarged resection of lower lamina is superior to equidistant enlarged resection of upper and lower laminas which is superior to enlarged resection of upper lamina in preventing SCI. These slides can be retrieved under Electronic Supplementary Material.

中文翻译：

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椎板切除术延伸与急性脊髓缩短引起的脊髓损伤之间的关系：山羊体内实验。

目的探讨活体山羊模型三柱截骨后急性椎体短缩后不同类型椎板切除术延伸与脊髓损伤之间的关系。方法选取18只健康山羊，完成双椎体切除术和T13和L1全椎板切除术，然后在体感诱发电位（SSEP）监测下进行不同的椎板切除术。根据随后的椎板切除术扩展的类型，将样品分为三组。在第一组（上层椎板扩大切除术）中，椎板切除术在距T12尾部10 mm处进行；在第二组中（上，下椎板组均等扩大切除），椎板切除术同时在T12的尾椎5 mm和L2的颅骨5 mm延伸。在第三组（下椎板扩大切除术）中，对10 mm的颅骨进行椎板切除术至L2。将椎骨切除后测量的SSEP设置为基线，并将SSEP从基线幅度降低50％和/或相对于基线峰值潜伏期延迟10％设置为阳性结果，这表明脊髓损伤。逐渐缩短脊柱，直到SSEP监测未显示阳性结果为止。在每组中测量缩短的距离（ΔH）和脊髓屈曲的改变角度（Δα）。术后2天通过Tarlov评分记录神经功能。结果三组的安全缩短距离分别为38.6±1.2mm，41.5±0.7mm，43.7±0.8mm。脊髓屈曲的相应改变角度分别为62.8±6.9°，82.8±7.5°和98.5±7.0°。通过LSD多重比较检验，三组之间的ΔH和Δα差异显着（P <0.05）。通过皮尔森相关检验，每组中ΔH和Δα之间都显示出很强的相关性。结论三柱截骨术后不同的椎板切除术扩展对急性脊髓缩短引起的SCI的预防作用不同。在预防脊髓损伤中，下层的扩大切除优于上层和下层的等距扩大切除，后者优于上层的扩大切除。这些幻灯片可以在电子补充材料下找到。通过LSD多重比较检验，三组之间的ΔH和Δα差异显着（P <0.05）。通过皮尔森相关检验，每组中ΔH和Δα之间都显示出很强的相关性。结论三柱截骨术后不同的椎板切除术扩展对急性脊髓缩短引起的SCI的预防作用不同。在预防脊髓损伤中，下层的扩大切除优于上层和下层的等距扩大切除，后者优于上层的扩大切除。这些幻灯片可以在电子补充材料下找到。通过LSD多重比较检验，三组之间的ΔH和Δα差异显着（P <0.05）。通过皮尔森相关检验，每组中ΔH和Δα之间都显示出很强的相关性。结论三柱截骨术后不同的椎板切除术扩展对急性脊髓缩短引起的SCI的预防作用不同。在预防脊髓损伤中，下层的扩大切除优于上层和下层的等距扩大切除，后者优于上层的扩大切除。这些幻灯片可以在电子补充材料下找到。结论三柱截骨术后不同的椎板切除术扩展对急性脊髓缩短引起的SCI的预防作用不同。在预防脊髓损伤中，下层的扩大切除优于上层和下层的等距扩大切除，后者优于上层的扩大切除。这些幻灯片可以在电子补充材料下找到。结论三柱截骨术后不同的椎板切除术扩展对急性脊髓缩短引起的SCI的预防作用不同。在预防脊髓损伤中，下层的扩大切除优于上层和下层的等距扩大切除，后者优于上层的扩大切除。这些幻灯片可以在电子补充材料下找到。