重度脊柱畸形VCR截骨矫形中椎板减压范围与脊柱脊髓安全短缩的量化关系

Correction of severe spinal deformities often requires osteotomy technology, and vertebral column resection (VCR) is the only effective technique to manage severe rigid spinal deformities. Howerver, spinal cord injury may occur in cases of excessive spinal shortening or distracting. Our previous studies have found that spinal cord shortening is safer than spinal cord distraction, and suggested that shortening of spinal cord is appropriate after osteotomy. The safe limit of shortening distance was strongly correlated with the vertebral body height. We also found the spinal cord was buckling as the spinal column was shortened gradually, and the safe limit of shortening distance may be largely related to the laminectomy resection length. However, where is the most effective decompression? What is the range of minimum effective laminectomy resection length? And, whether the different degrees of spinal shortening distance and laminectomy resection length have corresponding security quantitative relationship? This study aimed to investigate the relationship between spinal cord buckling angle and the safe limit of shortening distance, establish the safety relationship scale of the degree of spinal shortening distance and the laminectomy resection length, make clear the best location of laminectomy resection, gain reliable evidence that the lamina resection decompression can relieve buckling angle and improve the safety of spinal cord in a goat model. Futher more, we aimed to find out the quantitative relationship between the different degrees of spinal shortening and the laminectomy resection length to provide an important quantitative guidance standard for the safety correction of severe spinal deformity.

重度脊柱畸形必须借助脊柱截骨方能完成良好矫形，且常需全椎体截骨（VCR），而对截骨间隙进行过度的撑开或短缩都将引起脊髓损伤导致瘫痪。我们前期研究发现脊髓可耐受的撑开范围明显小于短缩范围，提出截骨后宜行脊柱短缩，并发现脊柱安全短缩距离与椎体高度存在明显相关性。前期研究还发现脊柱短缩时脊髓也将短缩堆积产生皱折，且其安全短缩幅度与后方椎板的切除减压范围密切相关。然而，最有效的椎板减压位置在何处？最小的切除范围是多少？不同程度的脊柱短缩与椎板减压范围是否存在对应的安全量化关系？项目拟通过山羊的动物实验，探讨脊髓皱折角度与脊髓短缩极限值之间的关系，获得椎板切除减压能够减轻脊髓皱折成角并提高脊髓安全性的可靠证据；建立脊柱短缩程度和椎板减压范围的安全关系量表，明确椎板的最佳切除位置和范围；进而量化重度脊柱畸形截骨矫形时的脊柱安全短缩范围及椎板减压范围，为重度脊柱畸形安全矫形提供一项重要的量化指导标准。

背景：对于重度脊柱畸形，必须借助脊柱截骨方能完成良好矫形，且常需全椎体截骨。由于VCR截骨时脊柱的前、中、后住均已切除，且常为多椎体截骨，矫形幅度往往较大，故矫形过程中易发生神经并发症。然而，目前对于如何在矫形过程中最大限度地避免脊髓损伤，有关的理论研究较少。我们前期研究发现脊髓可耐受的撑开范围明显小于缩短范围，提出截骨后宜行脊柱缩短，并发现脊柱安全缩短距离与椎体高度存在明显相关性。然而，我们前期完成的山羊动物实验只进行单椎体VCR截骨，进而得出脊柱安全缩短范围。那双椎体VCR截骨的脊柱安全缩短范围与单椎体VCR截骨的结果是否有差异？脊髓对皱缩的耐受性是否较好？且双椎体VCR截骨的脊柱安全缩短距离与椎体高度是否也存在相关性？脊柱缩短过程中，脊髓监测出现异常时，扩大椎板减压范围与撑开截骨间隙哪种脊髓减压方式优先？.主要研究内容：在前期研究基础上比较双椎体与单椎体VCR截骨的脊髓安全性差异，明确双椎体VCR截骨的脊柱安全缩短距离以及相关性分析，探索其脊柱安全缩短距离与椎体高度是否存在相关性。此外比较脊柱缩短过程中，脊髓监测出现异常时，扩大椎板减压范围与撑开截骨间隙两者对恢复神经功能的差异，明确脊髓损伤后优先的处理措施。.重要结果及关键数据：1. 双椎体VCR截骨的脊柱安全缩短距离为35.2±2.6 mm，它与前期实验中单椎体VCR截骨的脊柱安全缩短距离行单样本T检验，其差异有统计学意义， P＜0.05，两者均值差值为11.6mm。Pearson相关检验显示双椎体VCR截骨的脊柱安全缩短距离与胸13椎体高度、腰1椎体高度、胸13腰1平均高度、截骨间隙初始高度呈良好相关。2. 根据术后2日脊髓功能情况（Tarlov评分）使用卡方检验比较两组对恢复脊髓功能的差异，P=0.015（双侧），说明两组对恢复脊髓功能有明显差异，因Tarlov评分能较真实地反应脊髓功能状态，故其统计检验结果可信度较高。.科学意义：在山羊模型中，双椎体VCR截骨的脊柱安全缩短距离较单椎体VCR截骨的脊柱安全缩短距离要长，且它与截骨椎体高度及截骨间隙初始高度呈良好相关性，说明脊髓对皱缩的耐受性较好。在脊柱缩短过程中，脊髓监测出现异常时，应首先适当撑开截骨间隙，减少脊髓皱缩程度，再扩大椎板减压范围。