Impact of Diameter of Perforator in Pedicle and Different Managements of Intermediate Non-Pedicle Perforator on Flap Survival in Rats.

Backgrounds: The quantified relationship between perforator diameter and flap length can be supported, and the impact of different strategies of managements of a non-pedicled perforator with two major subfascial divisions on flap survival has never been explored.

Materials and methods: This study was divided into two parts. In Part I, 48 Sprague-Dawley rats underwent flap harvesting based on six perforators with a diameter gradient. Then, the flap length and perforator diameter were measured for establishment of an equation. In Part II, 32 rats underwent harvest of a transverse flap based on the right superficial epigastric perforator. In 16 rats the right intermediate iliolumbar perforator was severed in a distal-to-division approach, whereas, in the other 16 rats, it was severed with in a proximal-to-division approach. Necrosis rates and blood perfusion were also compared.

Results: The equation y = 13.02 × x + 2.29 could be established between the perforator diameter in the pedicle (x) and the flap length (y) that could be supported with R²=0.8963 and P < 0.001.The transverse flap with a distal-to-division management of the intermediate iliolumbar perforasome was weaker in perfusion and had a necrosis rate of 49±4%, whereas the flap with a proximal-to division management had a significantly stronger perfusion and a lower necrosis rate of 21±2% (P<0.001).

Conclusions: The safe flap length that can be estimated based on a perforator with a known diameter can be calculated using y=13.02× x +2.29. A short segment of the stem of an intermediate perforator with two major subfascial branches should be preserved to augment flap survival.