体内生物反应器构建定制型血管化骨组织及修复猴眼眶缺损

The repair of orbital bone defects caused by trauma, tumor or congenital anomaly, remains an immense challenge in reconstructive surgery. There are several types of artificial materials that are frequently used clinically for the orbital defect reconstruction. However, these materials are usually nondegradable or hard to be degraded, so they may cause rejection, infection, cyst formation, or implant metastasis. The clinical goal is to reconstruct custom-made three-dimensional bony tissue with blood vessel net in an anatomically functional morphology, which is an ideal approach for the treatment of orbital bone defects. Based on computer-aided design/computer-aided manufacturing (CAD/CAM), periosteal expansion technique and tissue engineer technology, the osteoinductive potential of the cranium periosteum are stimulated by raising the periosteum using a type of biodegradable distracted device in monkeys. The prefabricated functional bone tissue is used to accurately repair the autogenous orbital bone defect in three dimensions. The osteoinductive potential of periosteum and bone formation is evaluated in response to the dynamic elevation procedure. The effect of the mechanical strains and the related biochemical responses to stress force are also studied. After the prefabrication of the custom-made bone grafts, the grafts are transplanted into defects of the orbital bone, performing a microsurgical anastomosis and using miniplates for fixation. The reconstructive orbital bones are evaluated regarding visual functional and esthetic outcome.This research work will develop a new protocol for bone prefabrication and the orbital defect reconstruction, which has the potential to become an alternative for natural autogenous vascularized bone grafts and microsurgical transplantation for the orbital defect reconstruction in the clinic.

对外伤、肿瘤和先天异常等所导致的眼眶缺损进行修复重建是整形外科和眼科工作的难点。目前临床常用的眼眶修复材料存在排异反应、易感染和植入物移位等诸多问题。利用含有血管网络的定制型骨组织，解剖修复自体眶骨缺损是一种理想的治疗方式。本研究将在前期工作的基础上，把三维重建技术、骨膜牵张成骨技术和组织工程技术有机结合起来，设计一体内生物反应器，通过生物可降解支架定制牵张猴颅骨骨膜，预构含有血管网络的定制型组织工程眶骨，修复猴自体眶骨缺损模型。检测在牵张力学环境刺激下，骨膜的成骨潜能和方式，定制构建血管化骨组织的可行性和效果，并从视功能和形态学角度对修复结果进行评估。阐明应用本体内生物反应器构建定制型骨组织并用来修复骨缺损的可行性及优越性。本研究为利用生物体自身潜能构建骨组织提供了新思路，为组织工程技术进一步临床应用提供了理论依据。

目前针对外伤、肿瘤和先天异常等所导致的骨缺损进行治疗仍然存在着许多争议。随着交通事故以及工业外伤的频发，骨折病人较以往明显增多，无论是功能上的欠缺还是外形上的畸形，都给患者带来了极大的痛苦。对于骨折后，尤其是陈旧性骨折所造成的大块骨缺损进行功能和外形上的修复一直是重建外科领域的一项重大挑战。骨膜牵张成骨技术作为一种十分有前景的治疗骨缺损的技术，在骨表面和骨膜之间形成人工空间，仅通过牵张骨膜即可以再生出新生骨组织。在这项研究中，我们利用了三维打印和计算机辅助设计/制造技术的优势设计出三种不同孔隙大小的左旋聚左旋乳酸牵张支架，联合自体骨髓间充质干细胞观察牵张装置孔隙大小对骨膜牵张成骨的影响。扫描电镜观察发现不同孔隙大小的左旋聚乳酸左旋聚乳酸支架具有不同尺寸的微型通道，力学检测说明随着孔隙的增大，支架的力学强度随之降低，但体外实验均表明左旋聚乳酸具有毒性低，生物相容性好等优点，适于体内实验的开展。随后，我们在兔的颅骨骨膜下建立一个体内生物反应器，使用不同孔隙的牵张支架对兔颅骨骨膜进行动态牵张，经过八周的固定期后行微CT扫描和组织学染色检测新骨形成情况。动物实验表明构建的骨膜牵张成骨装置在体内具有一定的可行性。影像学和组织学结果均显示随着牵张装置孔隙的增大，骨膜牵张成骨的数量和质量均显著提高，表现在新生骨的骨量，骨密度，高度，血管化等方面的改善。该项研究是第一次将三维打印技术和骨膜牵张成骨技术相结合，三维打印可以辅助生产不同形状、不同结构和不同孔隙尺寸的材料，有利于对骨膜牵张成骨支架进行改造，从而生成更加成熟的功能性组织工程骨，不仅证实了骨膜牵张成骨技术的可行性，还为临床治疗大块骨缺损提供了新思路。