Histological Observation of Bone Reaction with Relation to Surface Treatment of Titanium

생체합금 Titanium의 표면처리에 따른 골반응의 변화에 대한 조직학적 관찰

The biocompatibility of the titanium has been estabilished through various experimental studies such as cell culture toxicity test, pyrogen test, mutagen test and others. In order to confirm biocompatibility after fabrication of titanium and to clarify the difference between the bone reaction after insertion of the lathed titanium rods and the bone reaction after insertion of the finished and polished rods, both rods were implanted into the proximal femur of a rabbit. Histologic reactions in the bone were observed according to the ASTM standards at the intervals of 6 weeks, 12 weeks and 26 weeks after implantation. The result were as follows : In 6 weeks after implantation of lathed titanium rods, inflammatory reactions, such as minimal degree infiltration of polymorphonuclear leukocytes and lymphocytes were observed in all cases. This was thought to he caused by surgical trauma. However, inflammatory cell infiltration was not seen after implantation of polished and finished rods in all cases. The cellular infiltration and the histologic reaction of the hone after implantation of lathed group were significantly more pronounced than those after implantation of the finished group. In 12 weeks after implantation of lathed rods, two of four cases revealed a minimal degree of cellular infiltration. No inflammatory cell infiltration was demonstrated after implantation of the finished group. The cellular infiltration and histologic reaction seemed to be more pronounced in the lathed group, but they were not significant statistically. At 26 weeks after implantation of the lathed and finished group, there was no cellular infiltration in both groups. New bone formation was observed up 26 weeks, and no difference between lathed titanium rods and finished titanium rods were apparent. Mild bone necrosis was observed in 1 case out of 11 cases in which lathed titanium rods were implanted. Bone necrosis was not observed in the finished titanium rod group. Fibrosis was observed in both groups, but differences were not significant between the experimental groups. In the lathed titanium rods group and the shorter interval group, inflammatory cell infiltration was significantly higher. Finished titanium rods and longer interval groups had markedly decreased tendences in histologic reaction ratings. As a conclusion, although certificated titanium might be safe to use, difference of biocompatibility were observed depending on the method of surface finish. By identifying biocompatibility as a long-term standardized animal study, we can develop progressed internal fixation device that is safe for human beings.

생체합금의 생체적합성을 검증하기위해, 표면처리가 되지 않은 타이타늄 봉과 표면처리를 시행한 타이타늄 봉을 실험용토끼의 대퇴골 근위부에 삽입하여 6주, 12주 및 26주후 방사선 관찰 후 광학현미경적 검사를 통한 골 반응을 비교 관찰하였다. 전 례에서 부식에 의한 반응은 관찰되지 않았으며, 신생골의 증식은 타이타늄의 삽입 후 26주까지 경도의 골증식이 관찰되었으나, 표면처리여부에는 관계가 없었다. 표면처리를 시행하지 않은 타이타늄의 삽입한 11례 중 1례의 경우 삽입 후 12주에 경도의 골괴사반응이 관찰되었으며 표면처리를 시행한 타이타늄을 삽입한 후 전 례에서 골괴사가 관찰되지 않았다. 이는 수술적 조작에 의한 것으로 사료되었다. 섬유원세포의 증식은 시기에 관계없이 전 례에서 관찰되었으며, 표면처리 여부 혹은 시간의 경과 정도와 관계가 없었다. 표면처리를 시행하지 않은 타이타늄의 삽입 후 6주에는 침윤정도 및 조직반응정도는 표면처리한 타이타늄의 삽입에 비해 통계적으로 유의하게 증가하였다. 그러나, 12주 및 26주 후에는 유의한 차이가 없었다. 다중회귀분석법의 단계별 투입방식을 이용하여 세포의 침윤율을 시간의 경과와 표면 처리여부에 따라 상관관계를 분석한결과, 세포 침윤율은 시간의 경과 및 표면처리를 하게 됨에 따라 감소하는 경향이 있었다. 조직 반응율의 정도도 침윤율과 유사한 양상을 나타내었다. 이상의 결과, 생체합금의 표면처리에 따라 골반응의 정도가 유의한 차이가 있었으므로 내고정 기구의 제작을 위해서는 보다 생체 적합성이 양호한 제작방법의 개발이 요구될 것으로 사료되었다.