Transmidline abdominal skin flap model in pig: refinements and advancements

Abdominal flaps have recently gained considerable popularity in breast reconstruction, and their importance and advantages have been widely accepted. Given the unreliability of the distal parts in these flaps and the advancement of microsurgery, many modifications and improvements have been made. To get a better understanding of these flaps, researchers have encouraged the search for a suitable flap model. The purpose of this study was to clarify the anatomical and physiological features of the transmidline abdominal flap model in pig. We included 16 white female Yorkshire pigs in this study. In six pigs, the vascular anatomy of the abdominal region was studied by multidetector row computed tomographic angiography and anatomic dissection. In the remaining 10 pigs, three kinds of transmidline abdominal flap models were established. The pigs were scanned on the abdominal flap to evaluate the perfusion zones after the true abdominal transmidline flap was created, and then they were sacrificed to determine the flap survival area 7 days after surgery. The results of the study were as follows. (1) The pig's deep inferior epigastric vessels were smaller than deep superior epigastric vessels both in length and diameters. (2) The deep superior epigastric artery always bifurcates into two groups; each group gives off five or six branches. (3) The superficial superior epigastric veins were present, while the superficial epigastric arteries were absent in all the animals included. (4) The linea alba abdominis was tough and lack of vascular structures. The average perfusion units were 197.0 ± 24.2, 103.2 ± 36.4, 138.8 ± 25.4, and 30.2 ± 11.8 from zone I to zone IV. All the flaps underwent partial necrosis. The flap survival area percentage was 85.9 ± 4.1%. The transmidline abdominal skin flap in pig is a reliable and true abdominal flap model for future physiological studies, especially the circulatory dynamics in transmidline abdominal flaps.