早发性脊柱侧凸新型生长棒治疗技术的动物实验研究

Early onset scoliosis has been defined as scoliosis in very young children, characterized by younger age and rapid curve progression. The management of progressive spinal deformities in very young children is a challenging task. Most nonfusion options, including VEPTR(Vertical Expandable Prosthetic Titanium Rib), and convential growing rods are problematic in one way or another owing to the desirability of repeated surgical lengthenings. The high complication associated with treatment of early-onset scoliosis include autofusion, infection, and fractures of rod or screws. The dilemma of the solutions for EOS requires new spinal implant to achieve the goal of correcting of the progressive curves and also allow normal spine growth. Thus, it was required to create a scoliosis model with a size similar to early onset scoliosis for the development of nonfusion techniques. With the support of key project of Nanjing Department of Health, a porcine model for early onset scoliosis was established, and a new growing rod was invented. The purpose of this study is to test the new growing rod pre-clinically and offer a valuable basis for the treatment of EOS.

早发性脊柱侧凸（early onset scoliosis, EOS）发生于低龄儿童，具有发病年龄早，畸形进展迅速等特点，其外科治疗非常困难。现有的非融合技术如VEPTR、生长棒等，需要多次撑开手术治疗，易产生自发性融合、感染、断钉断棒等并发症。目前临床中急需一种非融合技术，既可以达到生长棒固定的效果，不影响患儿脊柱长度发育的特点，又能避免多次手术带来的不便和感染、自发性融合等并发症。因而，构建生长特性类似于人类患儿的早发性脊柱侧凸动物模型，进而进行非融合技术的开发研究，成为脊柱侧凸非融合技术领域急需解决的热点问题。本研究前期在南京市卫生局重点项目资助下，已成功在幼猪中建立早发性脊柱侧凸模型，并研制成功新型生长棒，本项目拟进一步在幼猪生长高峰期前进行该新型生长棒矫形治疗的实验研究，为临床治疗早发性脊柱侧凸患儿提供有力的动物实验依据。

后路脊柱不对称性栓系可成功诱导建立早发性脊柱侧凸模型，且去除栓系内固定后，脊柱侧凸仍有明显进展。本项目先后对12只年龄约6周的幼猪进行单侧栓系造模，手术即刻侧凸角度29°；随访2月后，2只幼猪因伤口感染未完成实验，最终10只幼猪均出现结构性脊柱侧凸，侧凸角度平均65°。去除栓系内固定后，幼猪侧凸仍有明显进展，平均侧凸角度68°。故该不对称栓系造模具有一定的现实可行性，可成功诱导建立稳定的早发性脊柱侧凸模型，为早发性脊柱侧凸临床研究提供试验模型。.在此不对称栓系的力学负荷下,组织学分析提示凹侧肥大层软骨细胞数量少、形态异常、排列不规则，凸侧软骨细胞增殖活跃，肥大层明显增厚。该结果提示顶椎凹侧生长板软骨细胞的生长明显受到抑制,且以肥大层软骨细胞更为显著,使椎体凹侧纵向生长显著小于凸侧，导致椎体楔形变。.新型自动滑移型生长棒系统可有效矫正早发性脊柱侧凸。本项目将前期专利(自动延伸性能的滑动棒椎弓根钉脊柱侧凸生长棒系统，国家发明专利，申请号201110006480.9）应用于幼猪早发性脊柱侧凸的矫形治疗中。取.15头早发性脊柱侧凸建模成功的幼猪，随机分为生长棒治疗组(n=10)和对照组(n=5)。治疗组中2头幼猪植入生长棒后发生感染；治疗组生长棒植入术前Cobb角为52.1°，术后即刻Cobb角减小为25.4°，矫形术后8周治疗最终时Cobb角减少至20.2°；对照组造模完成时侧凸Cobb角为55.2°，取出内固定术后即刻Cobb角为53.6°，随访8周后观察其Cobb角为51.2°；治疗组脊柱生长长度为平均14.2 cm，生长棒体内滑动39.8 mm；对照组取出内固定术后8周内脊柱生长长度为平均14.9 cm。即自动滑移型生长棒系统能在矫正脊柱侧凸的同时，随脊柱生长而实现生长棒的延长滑动，并且该生长棒对幼猪脊柱的生长发育无显著影响。故该新型自动滑移型生长棒系统针对早发性脊柱侧凸具有较好的应用价值。