A polycaprolactone-tricalcium phosphate composite scaffold as an autograft-free spinal fusion cage in a sheep model
A polycaprolactone-tricalcium phosphate composite scaffold as an autograft-free spinal fusion cage in a sheep model
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聚己内酯-磷酸三钙复合支架作为绵羊模型中的无自体移植脊柱融合笼
DOI：
10.1016/j.biomaterials.2014.03.075
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发表时间：
2014-07-01
期刊：
影响因子：
14
通讯作者：
Zhang, Zhi-yong
中科院分区：
文献类型：
--
作者：
Li, Yi;Wu, Zhi-gang;Zhang, Zhi-yong
钛（Ti）基脊柱融合器在临床上常用于治疗脊柱退变及相关疾病，然而，其进一步的临床应用通常受到诸如应力遮挡、不可生物降解性和额外的骨移植手术的若干缺点的困扰。我们早期的工作已经证明了可生物降解的大孔聚己内酯-磷酸三钙（PCL-TCP）复合支架在促进骨组织向内生长以及在植入原位缺损部位后维持机械载荷的能力方面的功效。在这项研究中，我们在临床前绵羊模型中研究了PCL-TCP支架作为无自体移植物脊柱融合器的使用，为期12个月，并比较了与自体移植物结合的钛融合器的融合效果。结果显示，尽管PCL-TCP支架作为无自体植骨融合器在早期（6个月）获得较慢的融合率，但术后12个月时，其获得了与钛融合器辅助自体植骨相似程度的脊柱融合有效性，影像学和组织学评价证明了这一点。从组织学和显微CT分析中可以看出，单独使用PCL-TCP融合器的骨长入更好，骨/间隙比（B/I）是钛融合器的2.6倍，骨组织分布更均匀（88.10 +/- 3.63% vs. 33.74 +/-2.78%，p < 0.05）。此外，除了骨组织长入外，还说明了一种定量方法，可准确评价融合器与周围骨组织的骨整合，并且显示PCL-TCP融合器组的骨整合程度是Ti融合器组的1.36倍（CS/PC：79.31 +/- 3.15% vs 58.44 +/-2.43%，p < 0.05）。此外，生物力学分析显示，两组融合节段在12个月时的活动度和刚度方面的机械强度相当（p > 0.05）。观察到PCL-TCP椎间融合器的降解特征随着新骨长入孔隙而增加，同时保持支撑脊柱椎间节段所需的良好结构完整性。因此，PCL-TCP融合器具有更好的骨整合性、更多的骨组织长入以及良好的生物降解性和放射性，已被证明是一种有前途的候选物，可作为临床应用的自体无移植物融合器。(C)2014爱思唯尔有限公司版权所有。
Titanium (Ti) based spinal fusion cages are frequently used in the clinics for the treatment of spinal degeneration and related diseases, however, their further clinical application is generally harassed by several drawbacks such as stress shielding, non-biodegradability and additional bone grafting procedure. Our earlier work has demonstrated the efficacy of a biodegradable macro-porous polycaprolactone-tricalcium phosphate (PCL-TCP) composite scaffold in promoting bony tissue ingrowth as well as its ability to sustain mechanical loads upon implantation into an orthotopic defect site. In this study, we investigated the use of PCL-TCP scaffold as an autograft-free spinal fusion cage in a preclinical sheep model over 12 months, and compared the fusion efficacy against Ti cages incorporated with autografts. Results showed that despite PCL-TCP scaffold as an autograft-free cage attaining a slower fusion rate at early stage (6 month), it achieved similar degree of spinal fusion efficacy as Ti cages aided with autograft at 12 month post-operation as evidenced by the radiographic and histological evaluation. PCL-TCP cages alone demonstrated better bone ingrowth with 2.6 fold higher bone/interspace ratio (B/I) and more homogeneous bone tissue distribution compared with that of the Ti cages (88.10 +/- 3.63% vs. 33.74 +/- 2.78%, p < 0.05) as seen from the histological and micro-CT analysis. Moreover, besides the bone tissue ingrowth, a quantitative approach was illustrated to accurately evaluate the osteointegration of fusion cage with surrounding bone tissue, and showed a 1.36 fold higher degree of osteointegration occurred in PCL-TCP cage group than Ti cage group (CS/PC: 79.31 +/- 3.15% vs 58.44 +/- 2.43%, p < 0.05). Furthermore, biomechanical analysis showed comparable mechanical strength of fused segments in both groups in terms of the range of motion and stiffness at 12 month (p > 0.05). The degradation profile of the PCL-TCP cages was noted to increase in tandem with new bone ingrowth into the pores, while maintaining good structural integrity necessary for supporting the spinal interbody segments. Therefore, with the better osteointegration, more bone tissue ingrowth as well as its favorable biodegradable and radiolucent properties, PCL-TCP cage has been demonstrated to be a promising candidate as an autograft-free fusion cage for clinical application. (C) 2014 Elsevier Ltd. All rights reserved.