Kontio R, Ruuttila P, Lindroos L, Suuronen R, Salo A, Lindqvist C, Virtanen I, Konttinen Y T
Department of Oral and Maxillofacial Surgery, Helsinki University Hospital, P.O. Box 263, Huch, Helsinki 00029, Finland.
Int J Oral Maxillofac Surg. 2005 Oct;34(7):766-76. doi: 10.1016/j.ijom.2005.04.027.
Several implants for orbital wall fracture treatment are available at the present, but they have drawbacks: resorption, risk for migration and foreign body reaction. Alloplastic resorbable implants would be advantageous: no removal operation and no donor side morbidity. The purpose of this study was to evaluate the foreign body reaction, capsule formation and mechanical properties of two bioresorbable implants. PDS and SR-P(L/DL)LA mesh sheet (70/30) with solid frame (96/4) implants (SR-P(L/DL)LA 70,96) were placed into subcutaneous tissue of 24 rats. Immunohistochemistry was used to evaluate reactivity for Tn-C, alpha-actin, type I and III collagens and two mononuclear cells: T-cells and monocyte/ macrophage. GPC, DSC and SEM were performed. Student's t-test or nonparametric Kruskall-Wallis test were used for statistical analysis. Histology of peri-implant capsule exhibited an inner cell-rich zone and an outer connective tissue zone around both materials. Tn-C reactivity was high in the inner and alpha-actin in the outer zone. At the end of the study, the difference of type I collagen versus type III collagen reactivity in inner zone was statistically significant (P<0.0001) as was the difference of type I collagen versus type III collagen reactivity in outer zone (P<0.0001). Immunohistochemistry did not reveal any statistical differences of T-cell and monocyte/macrophage reactivity around PDS versus SR-P(L/DL)LA 70,96 implants, nor any differences as a function of time. PDS were deformed totally after 2 months. SR-P(L/DL)LA 70,96 implants were only slightly deformed during the follow up of 7 months. PDS degraded rapidly in SEM observation. Particles were detaching from surface. SEM observation revealed that polylactide implant was degrading from the surface and the inner porous core became visible. The degradation came visible at 7 months. There were cracks in perpendicular direction towards to the long axis of the filaments. M(w) of PDS decreased fast compared to the polylactide implant. Foreign body reaction was minimal to both materials but continued throughout the whole observation period. Mechanically PDS was poor, it looses its shape totally within 2 months. It cannot be recommended for orbital wall reconstruction. New mesh sheet-frame structure (SR-P(L/DL)LA 70,96) approved to be mechanically adequate for orbital wall reconstruction. It seems not to possess intrinsic memory and retains its shape. The resorption time is significantly longer compared to PDS and is comparable to other studied P(L/DL)LA copolymers. Thus, the new polylactide copolymer implant may support the orbital contents long enough to give way to bone growth over the wall defect.
目前有几种用于眼眶壁骨折治疗的植入物，但它们存在缺点：吸收、移位风险和异物反应。异体可吸收植入物将具有优势：无需取出手术且无供体部位并发症。本研究的目的是评估两种生物可吸收植入物的异物反应、包膜形成和力学性能。将PDS和带有实心框架（96/4）的SR-P（L/DL）LA网片（70/30）植入物（SR-P（L/DL）LA 70,96）置于24只大鼠的皮下组织中。采用免疫组织化学方法评估对肌钙蛋白C、α-肌动蛋白、I型和III型胶原蛋白以及两种单核细胞：T细胞和单核细胞/巨噬细胞的反应性。进行了凝胶渗透色谱法（GPC）、差示扫描量热法（DSC）和扫描电子显微镜（SEM）观察。采用学生t检验或非参数克鲁斯卡尔-沃利斯检验进行统计分析。植入物周围包膜的组织学显示，两种材料周围均有一个内部富含细胞的区域和一个外部结缔组织区域。肌钙蛋白C在内部区域反应性高，α-肌动蛋白在外部区域反应性高。在研究结束时，内部区域I型胶原蛋白与III型胶原蛋白反应性的差异具有统计学意义（P<0.0001），外部区域I型胶原蛋白与III型胶原蛋白反应性的差异也具有统计学意义（P<0.0001）。免疫组织化学未显示PDS与SR-P（L/DL）LA 70,96植入物周围T细胞和单核细胞/巨噬细胞反应性的任何统计学差异，也未显示随时间变化的任何差异。2个月后PDS完全变形。在7个月的随访期间，SR-P（L/DL）LA 70,96植入物仅轻微变形。在扫描电子显微镜观察中，PDS降解迅速。颗粒从表面脱落。扫描电子显微镜观察显示聚丙交酯植入物从表面开始降解，内部多孔核心可见。7个月时降解明显可见。在与细丝长轴垂直的方向上有裂缝。与聚丙交酯植入物相比，PDS的重均分子量（M(w)）下降很快。两种材料的异物反应均最小，但在整个观察期内持续存在。在力学性能方面，PDS较差，在2个月内完全失去形状。不推荐用于眼眶壁重建。新型网片-框架结构（SR-P（L/DL）LA 70,96）经证实力学性能足以用于眼眶壁重建。它似乎不具有内在记忆性并能保持其形状。与PDS相比，其吸收时间明显更长，与其他研究的聚（L/DL）丙交酯共聚物相当。因此，新型聚丙交酯共聚物植入物可能足够长时间支撑眼眶内容物，以便在壁缺损处让位于骨生长。
