The effects of gravity on delayed and transplanted delayed tubed flaps.

Altering the position (elevated or dependent) had no immediate effect on the blood supply of delayed or transplanted delayed tubed flaps. However, after 72 hours the mean survival length in the dependent tubes was less than that in the elevated tubes. (This difference was only significant in the delayed untransplanted flaps, and not so in the delayed transplanted flaps). All of the dependent tubes had a significant increase in water content (compared to the elevated tubes). This increase was greater in the transplanted delayed tubed flaps. The tissue pCO2 levels were significantly increased after 24 hours in the dependent transplanted tubes, reflecting poor circulation and ischemia in them. The rate of clearance of subcutaneously injected technetium-99m was significantly increased in the dependent transplanted tubes after 72 hours, while in the elevated tubes the clearance rate was similar to that in normal skin. The morphological appearance of the vessels in these flaps complemented the results of the functional study.