Feasibility Of Skin Soft Tissue Expansion By Air-inflated Expander

Background: Skin and soft tissue expansion provide matched donor skin tissues for reconstruction of hair loss,scar,skin defects,and other defects with irreplaceable advantages.But this technique is accompanied with shortcomings such as long period of expansion,several clinical complications,and other negative impact on patient’s daily life.Persistant efforts have made to improve the efficiency of the expansion,reduce complications,and improve patient experience.Several expansion modes,such as rapid expansion,constant pressure expansion,and constant speed expansion,are commonly utilized in modern plastic surgery and all have achieved good results.However,gravity related complications that occur clinically include expander exposure and displacement,flap necrosis,patient inconvenience and other issues.Based on the above analysis,expansion of skin and soft tissue by air-inflated expanders may effectively solve the above problems.As there are few studies to characterize the application of air-inflated expanders,we therefore establish an animal model to test the feasibility of skin and soft tissue expansion by air-inflated expanders and compare the efficacy of expansion with routine saline-filled expanders.Part 1 A rabbit model of skin and soft tissue expansion at parietal regionObjective: To establish a skin and soft tissue expansion model at rabbit parietal region,characterize the histological changes,the expansion and contraction properties of the expanded skin tissues,evaluate the expansion efficacy and the reproducibility of this model.Methods: Twenty New Zealand White rabbits,each weighing 3kg,were divided into group A(n = 10)and control group B(n =10).A skin and soft tissue expander with 80 ml capacity was implanted subcutaneously at parietal region of each rabbit in group A followed by daily expansion with injection of saline until the internal pressure of the expander reached 30 mmHg.The whole process of expansion was completed within 20 post-implantation days for each animal.Rabbits in group B received expander implantation but without expansions.The expansion efficacy and contraction of expanded skin were determined.Histological changes of skin biopsies collected from the centers of the expanded areas were evaluated microscopically.Results: Robust skin expansion was acheived in rabbits of group A and the skin tissues thickened after the expansion.Conclusion: Rabbit parietal expansion by skin and soft tissue expanders provides a satisfactory model for skin expansion research.Part 2 Experimental study on the feasibility of skin and soft tissue expansion byair-inflated expanders at the rabbit parietal regionObjective: To evaluate the rates of expansion and contraction,tissue morphological changes and complications during the procedure of expansion with air-inlfated expanders,to explore the feasibility of the expansion method,and to provide practical guidance for clinical application.Methods: Twenty New Zealand White rabbits,each weighing 3kg,were divided into group A(n = 10)and control group B(n =10).A skin and soft tissue expander with 80 ml capacity was implanted subcutaneously at parietal region of each rabbit in group A followed by daily expansion with injection of gas until the internal pressure of the expander reached 30 mmHg.A skin and soft tissue expander with 80 ml capacity was implanted subcutaneously at parietal region of each rabbit in group B followed by daily expansion with injection of saline until the internal pressure of the expander reached 30 mmHg.The whole process of expansion was completed within 20 post-implantation days for each animal.The expansion efficacy and contraction of expanded skin were determined.The complications of the two groups were observed.Histological changes of skin biopsies collected from the centers of the expanded areas were evaluated microscopically.Results: There was no significant difference in the expansion efficacy between the expansions by air-inflated and saline-filled expanders.The expanded skin tissues showed thickened epidermis,enlarged and disordered dermal collagen fibers infiltrated with inflammatory cells relative to the normal skin control samples.Conclusion: The efficacy of expansion by air-inflated expanders is equevelant to that by saline-filled expanders.In comparison with the saline-filled expanders,air-inflated expanders possess several advantages that include ease of usage,light load burden,low rate of complications that is directedly caused by gravity and warrant further study.