可吸收聚对二氧六环酮线的制作及骨折内固定的实验研究

目的　利用自行合成的可吸收聚对二氧六环酮(PDS)线固定家兔下颌骨体部骨折,观察骨折愈合及内固定线降解吸收情况。方法　以亚乙基二醇及金属钠等为原料,合成对二氧六环酮单体;在一定温度、压力及催化剂条件下将单体开环聚合而得PDS;将压出成形,拉伸成线的PDS用于实验组12只成年雄性新西兰兔的单侧下颌骨体部骨折内固定,以每2周为一个时间点处死2只动物直至12周。对照组相同骨折而不作任何内固定的6只动物仍按相同时间点处死。通过X线片和组织学观察骨折愈合及内固定线降解吸收情况。结果　实验组所有动物骨折愈合良好,骨折区域外骨痂形成明显,膜内成骨及软骨内成骨均存在;PDS在体内先发生强度的衰减,继之缓慢吸收。不作内固定的对照组动物骨折均不能愈合。结论　自行合成的PDS线是一种可吸收并具有一定强度及柔韧性的无色热塑性单丝纤维,可通过环氧乙烷薰蒸灭菌而不影响其强度,可有效地进行下颌骨骨折的内固定,有进一步研究的价值。

Chemical Synthesis of Biodegradable Poly-para-dioxanone and Its Application for Mandibular Fracture Fixation

Objective To observe mandibular fracture healing after synthesized bioabsorable poly-para-dioxanone (PDS) ligature fixiation.Methods Para-dioxanone monomer was prepared by chemical reactions of metallic sodium, ethylene glycol and other raw materials. PDS was synthesized by polymerizing the purified para-dioxanone in the presence of catlyst under the conditions of negative pressure and certain temperature. PDS ligature was obtained by processing the polymer into small granules, drying and melt-extruding through a spinnerette. Eighteen adult male New Zealand rabbits were assigned randomly into two groups. After mandibular fracture models were created, reductions of the artificial fractures were accomplished by means of transosseous PDS ligatures on each of 12 rabbits in experimental group. While the other six rabbits without any internal fixation were set as control. Schedules for killing were arranged to give postoperative samples at two-week interval till 12th week.Results Radiographical and histological examinations demonstrated that all fractures fixed with PDS ligatures healed without any complication. Periosteal and cartilaginous osteogenesis was observed in newly formed external callus. In contrast, bone fragment migration and the consequent nonunion occurred in the control group. PDS ligature degraded and absorbed without interference with osseous union and healing. The tensile strength reduction of PDS ligature was prior to its absorption in vivo.Conclusion The synthesized PDS is a colorless, flexible, themoplastic and monofilament fiber, which can be sterilized by ethylene oxide embalmment without serious loss of tensile strength. It seems that the application of this macromolecular material in internal fixation is of great worth for further study.