Comparison of rapid versus slow tissue expansion on skin-flap viability.

The effect of rapid versus slow tissue expansion on random-pattern skin-flap survival lengths was evaluated in two groups of pigs. Each group (group 1--slow; group 2--rapid) was further evaluated for the effect that delay (A), delay plus expansion (B), expansion only (C), and acute flap elevation (D) had on flap length viability. Intergroup and intragroup comparisons were made. In the slowly expanded group, significantly greater flap length viabilities were demonstrated in the slow expansion flaps as compared with the delay plus expander flaps and the delayed flaps, respectively. In the rapidly expanded group, the flap length viabilities of flaps C, B, and A were statistically equal. However, the flap length viability of the rapidly expanded flaps was statistically equal to that of the slowly expanded flaps (C1 = C2). The effect tissue expansion has on improving flap length viability as compared with the delay phenomenon may be related to the combination of a delay effect plus increased nutrient flow density that slow expansion produces. This combined metabolic enhancement is preserved with rapid tissue expansion.