Creating a free muscle flap by neovascularization: an experimental investigation.

Experimental free muscle flaps were created by inducing transmural neovascularization. Free muscle flaps were developed in Sprague-Dawley rats through a three-stage microsurgical procedure. In the first stage, a muscle strip from the external oblique abdominus muscle was elevated and folded around the superficial epigastric vessels. At six days, the second stage was performed in which the muscle flap was detached from its origin and partially elevated, demonstrating that the muscle had developed an acquired terminal axial pedicle. At 12 days, the third stage was performed in which the muscle flap on its new pedicle was transplanted to a new site. Neovascular free flap survival was documented at intervals of three hours, one day, and six days post free transfer. Plastic casts of the muscle flap vascular tree were made to demonstrate neovascularization.