Detailed Vascular Anatomy and Flap Harvest Technique of the Serratus Anterior/Rib Composite Flap.

Background: The hemodynamics of blood flowing from the anterior serratus to the ribs has yet to be analyzed in detail in serratus anterior/rib composite flaps. The authors focused on new blood circulation, whereby the slip arteries branched from the serratus anterior branch, off the thoracodorsal artery and the intercostal arteries, directly through the interconnecting vessels (axial route). The authors analyzed in detail the hemodynamics of serratus anterior/rib composite flaps and developed a new method for flap elevation.

Methods: The axial route was identified and analyzed by performing macroscopic autopsies of formalin perfusion-fixed cadavers involving three-dimensional computed tomographic angiography and vascular corrosion casting. Flap elevation was performed with new blood circulation, which included the axial route, and blood flow was evaluated using indocyanine green fluorescence angiography.

Results: The interconnecting vessels penetrated the intercostal muscles at a mean distance of 4.5 cm from the anterior margin of the attachment sites of the serratus anterior muscle to the ribs and at a mean distance of 7.4 cm from the costochondral junction. The interconnecting vessels had a mean diameter of 0.5 mm. Vascular corrosion casting helped identify multiple capillaries that were distributed from the intercostal arteries to the periosteum of the ribs. In addition, intraoperative indocyanine green fluorescence angiography confirmed blood flow from the slip arteries to the intercostal arteries.

Conclusion: Good blood flow in harvested graft tissue can be achieved by including the axial route with the periosteal blood circulation at the rib attachment sites of the serratus anterior in a serratus anterior/rib composite flap.