多孔TCP人工骨修复肿瘤性骨缺损的临床效果与骨愈合机制探讨

目的 观察应用多孔TCP人工骨修复肿瘤性骨缺损的临床效果和骨愈合机制,提出"结构移植"新理论.方法 2003年1月-2005年12月,应用多孔TCP人工骨颗粒材料修复各种原发性良性骨肿瘤切除后遗留骨缺损61例.男33例,女28例;年龄9个月～46岁.骨纤维结构不良8例,骨囊肿23例,嗜酸性肉芽肿12例,内生软骨瘤13例,非骨化纤维瘤2例,骨母细胞瘤3例.肿瘤范围1.5 cm× 1.0 cm～7.0 cm× 5.0 cm.肿瘤切除后缺损范围为2.0cm×1.5 cm～8.0 cm×5.0 cm.术后不同时间点行X线片、单光子发射计算机断层骨扫描(single photon emission computed tomography,SPECT)、在体TCP人工骨降解的X线影像学半定量研究以及组织病理学观察TCP人工骨降解情况.结果 术后患者一般情况良好,伤口均I期愈合.61例获5～24个月随访.骨缺损于术后1～6个月均愈合,骨愈合率达96.7%.除1例坐骨嗜酸性肉芽肿患者术后3个月肿瘤复发,再次手术治疗后痊愈,余患者无复发.X线片观察术后1个月即可见植骨与宿主骨结合部间隙模糊,新骨开始形成3个月植骨从周围向中心开始吸收,周围与中心均可见新骨形成;6个月植骨与宿主骨融合,骨缺损完全修复,移植材料降解率为78.9%;12个月植骨大部分吸收,骨质改建塑形,部分髓腔再通;24个月骨质塑形改建良好,髓腔再通.术后1个月SPECT观察,显示局部有较多核素浓聚,骨代谢旺盛,植骨中心核素有明显浓聚,为中心诱导成骨现象.组织病理学观察,TCP人工骨颗粒与宿主自体骨结合紧密,植骨处有大量骨软骨组织形成,充填骨孔洞内外深部有新生血管样组织长入,于植骨内部及周围形成有较多细胞围绕的"镶边"状结构.结论 多孔TCP人工骨修复肿瘤性骨缺损临床效果良好.其内部多孔三维结构模拟人骨天然仿生"自组织"结构,有利于募集细胞长入支架深部,达到良好的血管化并最终形成修复性新骨组织,兼具骨传导和骨诱导的骨愈合机制,为一高效新型"结构性"骨移植修复材料.

CLINICAL RESULTS AND THE MECHANISM OF BONE HEALING FOR THE REPAIR OF BONE DEFECTS DUE TO TUMOR RESECTION WITH NOVEL INTERPOROUS TCP

OBJECTIVE: To investigate the clinical results and the mechanism of bone healing for the repair of bone defects following tumor resection with novel interporous TCP bone graft, and to test the hypothesis of "structural transplantation". METHODS: From January 2003 to December 2005, 61 cases of various bone defects following the curettage of the benign bone tumors were treated with interporous TCP, with 33 males and 28 females, including bone fibrous dysplasia in 8 cases, bone cyst in 23 cases, eosinophilic granuloma in 12 cases, enchondroma in 13 cases, non-ossifying fibroma in 2 cases, and osteoblastoma in 3 cases. Tumor sizes varied from 1.5 cm x 1.0 cm to 7.0 cm x 5.0 cm. The plain X-ray, single photon emission computed tomography (SPECT) and histology examination were obtained at various time points after operation. The in vivo biodegradation rate of the implanted TCP was evaluated based on a semi-quantitive radiographic analyzing method. Histopathology examination was performed in 1 revision case. RESULTS: All the patients were followed up for 5 to 24 months after operation. They all had good wound healing and bone regeneration. There was neither significant reverse reaction to the transplanted material nor locally inflammatory reaction in all of the cases. The bone defects were repaired gradually from 1 to 6 months after operation (bone healing at average 2.6 months after surgery) with a bone healing rate up to 96.7%. There was only 1 recurrence case (eosinophilic granuloma in ischium) 3 months after operation. Given revision operation, this case gained bone healing. Radiographically, the interface between the implanted bone and host bone became fuzzy 1 month after implantation, indicating the beginning of new bone formation. Three months later, the absorption of the interporous TCP was noticed from peripheral to the center of the implanted bone evidenced by the vague or fuzzy realm. New bone formation could be seen both in peripheral and central areas. Six months later, implanted bone and host bone merged together and the bone defect was totally repaired, with 78.9% degradation rate of the implanted TCP. Twelve months later, the majority of the implanted bone was absorbed and bone remodeling was established. In the cases that were followed up for 24 months, the function of affected extremity was excellent with good bone remodeling without recurrence. In 2 cases, SPECT showed that nuclide uptake could be observed in implanted site and the metabolic activity was high both in the central as well as the peripheral areas of the graft 1 month after implantation, which was an evidence of osteogenesis. Pathologically, the interporous TCP closely contacted the host bone inside the humerus 1 month after grafting. The interface between the implanted bone and host bone became fuzzy, and vascularized tissue began growing inside the implanted graft as a "lining" structure. CONCLUSION: The interporous TCP proves to be effective for clinical reparation of bone defects following tumor resection. The inside three-dimensional porous structure simulates the natural bionic bone structure which is suitable for recruitment related cells in-growth into the scaffold, colonizing and proliferation companied with the process of vascularize, finally with the new bone formation. The novel interporous TCP may boast both bone conductive and bone inductive activities, as an appealing "structural transplantation" bone graft.