Moderators of angiogenesis in muscle flaps: a non-randomised animal study

Publication date: Available online 23 April 2018
Source:Journal of Plastic, Reconstructive & Aesthetic Surgery
Author(s): K. Bradshaw, M. Wagels
IntroductionA muscle flap can survive a pedicle injury under favourable conditions. In the reconstruction of compound limb injuries, the wound milieu is variable and may affect the rate and manner of neovascularisation. Our aim is to determine the effect of some key clinical variables on neovascularisation in muscle flaps in an animal model.MethodologyPectoralis profundus was raised in 60 rats and covered with skin graft. Fifteen cases were allocated to groups: separation of the flap from the skin inset (S), inflammation by inoculation with Staphylococcus aureus (I), flap elevation with Harmonic Scalpel (H), preservation of the motor nerve (N) and compared to controls (C). Graft-take and wound complications were assessed five days later, as well as perfusion before and after pedicle ligation, using Laser Doppler Flowmetry and neovascularisation using barium angiography.ResultsFlaps with an intact motor nerve had significantly higher graft take than controls (59% vs 29%). Perfusion changed less than controls in all study groups, though the extent of flap necrosis was not significantly different. Only flaps raised with the harmonic scalpel generated more new vessels than controls at the inset (9.6 vs 3.2), particularly at the origin of the muscle (1.10 vs 0.19).ConclusionsAll study groups were less dependant on their pedicle for perfusion than controls. The use of the harmonic scalpel and increased inflammation seem pro-angiogenic, though they do not reduce flap necrosis after simulated pedicle injury. Neovascularisation will preferentially bridge to skin at the inset rather than tissues in the base of the wound. It is likely that flap necrosis is the result of a combination of unfavourable variables rather than one in isolation.