RESUMEN
Objective To reveal the relationship between NOS,CD34 expression and the flap survival area,and to explore the survival mechanism of narrow strip flap,by designing different skin flaps with a slender narrow pedicle in a certain proportion of length to width on pigs' backs.Methods Five narrow flaps were formed on each side of the five white domestic pigs' back,of which pedicle width length ratio were 2 cm:4 cm,the area of the flaps was 2 cm × 2 cm,3 cm × 3 cm,4 cm ×4 cm,5 cm × 5 cm,and 6 cm × 6 cm,respectively,and named as flaps A,B,C,D,and E in turn.Besides,the flap A was taken as control.After the operation,the flaps were evaluated with general obveration,and NOS and CD34 expression and survival area were analyzed.Results For groups A,B and C flaps,the expression level of NOS and CD34 gradually elevated as the flap increased in size,and flaps completely survived (P＜0.05) ; For flaps in groups D and E,when distal end of flap was partial necrosis,the expression level of NOS and CD34 no longer elevated with the increase of skin flap area,and their expression was relatively constant (P＞0.05).Conclusions The survival area of the skin flaps is not in proportion to the width of its pedicle.Thus there is a maximum survival area of a skin flap carried by slender narrow pedicle in a certain proportion of length to width.