Three-dimensional CT angiography assessment of the impact of the dermis and the subdermal plexus in DIEP flap perfusion

Background Single-stage breast reconstruction following skin-sparing or nipple-sparing mastectomy with free deep inferior epigastric perforator (DIEP) flap usually does not require a large skin paddle. Most of the flap skin paddle is removed, and the flap is placed under native, conserved skin to provide adequate volume to the reconstructed breast mound. We hypothesized that conservation of intact dermis and its subdermal plexus has a critical role in overall flap perfusion through recruitment of indirect linking vessels. The study goal was to investigate and compare the vascularity of DIEP flaps with intact dermis versus DIEP flaps with the dermis removed. Methods Twelve hemi-DIEP flaps were harvested from fresh cadavers. The largest dominant perforator was cannulated using a 24-gauge butterfly catheter. Flaps were imaged with computed tomography (CT) after injection of a contrast agent. After scanning, the contrast agent was flushed out of the flap. The flap skin was removed with cautery at the subdermal dissection plane. The flaps were reimaged with CT after injection of the contrast agent. Three-dimensional (3-D) CT angiographic reconstructions were obtained for each protocol stage, and the percentage of flap perfusion was calculated. Flap vascularity with and without dermis was compared. Results A mean difference of 25.9% in flap perfusion occurred when the dermis was removed (P < 0.001). The 3-D CT angiographic images showed that the impact of dermis excision was caused by interrupting the recurrent flow through the dermis and subdermal plexus via indirect linking vessels. Conclusion The dermis has a significant role in enhancing overall DIEP flap perfusion through preservation of indirect linking vessels organized in the subdermal plexus. Despite being time consuming, a cautious de-epithelialization of the DIEP flap should be performed to retain dermis integrity. Enhancement of flap vascularity ultimately leads to a decrease in such complications as partial or total flap necrosis, as well as fat necrosis.