The effects of varying degrees of tension on the viability of skin flaps in pigs.

When pig skin is progressively extended the graphs obtained are similar to those in man. There are directional variations depending on the orientation of flaps to Langer's lines. A variety of flaps were subjected to 3 grades of tension: normal, i.e. the flap sutured into its original position; slightly stretched; maximally stretched. Flaps sutured in their normal position were no different from those sutured in their retracted position. The surviving length in each group did not differ significantly but flaps under maximal tension were more likely to undergo distal necrosis.