Auricle reconstruction with a nickel-titanium shape memory alloy as the framework.
OBJECTIVE
The objective of this study is to explore the biocompatibility and implantability of a nickel-titanium (NiTi) alloy in auricle reconstruction.


METHODS
Twelve New Zealand rabbits underwent subcutaneous implantation with a NiTi alloy framework shaped like the human auricle under general anesthesia. The implant was inserted after skin expansion. Implant vascularization was evaluated at months 1, 3, 6, 9, and 12 after implantation by histologic analysis. Immunohistochemical methods were used to examine expression of vascular endothelial growth factor in tissue around the implant. The fibrovascular ingrowth rate of implants was determined by bone scanning using (99m)Tc-PYP. The surface of the NiTi alloy implant was examined microscopically with scanning electron microscopy.


RESULTS
The implant harvested showed only partial vascularization at 1 month and completely vascularized at 3 months. The amount of vascular endothelial growth factor-positive cells was markedly increased at 6 months and reached the highest number at 3 months. The fibrovascular ingrowth rate of implant was assessed by (99m)Tc-PYP bone scan using ratios of (99m)Tc-PYP activity in placement regions versus the contralateral normal region. One rabbit had exposure of the NiTi alloy framework as a result of overlying skin flap necrosis. It was rescued with animal skin without the complete removal of the framework. All the other rabbits tolerated the implant well, and there were no complications.


CONCLUSIONS
The NiTi alloy implant represents an alternative implant for auricular reconstruction.
Chi
Fang-Lu
FL
Department of Otology and Skull Base Surgery, Eye and ENT Hospital, Fudan University, Shanghai, People's Republic of China. chifanglu@yahoo.com
Wang
Shen-Jun
SJ
Liu
Hong-Jian
HJ
D000497:Alloys; D000818:Animals; D001672:Biocompatible Materials; D003094:Collagen / Q000648:ultrastructure; D004431:Ear, External; D006801:Humans; D008855:Microscopy, Electron, Scanning; D018919:Neovascularization, Physiologic / Q000502:physiology; D009532:Nickel; D049268:Positron-Emission Tomography; D011817:Rabbits; D040521:Subcutaneous Tissue / Q000473:pathology / Q000601:surgery; D013499:Surface Properties; D013997:Time Factors; D023822:Tissue Engineering; D015626:Tissue Expansion; D014025:Titanium; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis
D000497:Alloys; D001672:Biocompatible Materials; D042461:Vascular Endothelial Growth Factor A; C040654:titanium nickelide; D009532:Nickel; D003094:Collagen; D014025:Titanium