Comparing the resistance of axial or perforator flap pedicle patern to the torsion; Study of improving resistance of a flap to torsion with delay phenomen

The torsion of the flap's pedicle is one of the most common conditions causing vascular compromise. Although it is usually noted as an accident and an imperfection of the technique, sometimes it is mandated by the topology of the flap transfer and, according to its degree, compromises the flap circulation. We aimed to compare the resistance to torsion of axial flap pedicle and perforator pedicle patterns. In the second part of the study we investigated whether the delay phenomenon is an effective method of improving flap resistance to pedicle torsion. In the first phase, 100 male Wistar rats weighing 200 to 250 g were used. The lower abdomens of 50 of the animals were shaved, and bilateral island groin flaps measuring 3x3 cm were elevated on the basis of the superficial inferior epigastric vessels. The right-side flaps were sutured back into place and used as controls in all animals. The rats were then randomly divided into five groups according to the procedure performed on the left side. Each group contained 10 animals. In group I, the flap was rotated 90 degrees in a clockwise direction and sutured into place. Rotation was 180 degrees in group II, 270 degrees in group III, 360 degrees in group IV and 720 degrees in group V. The posterior thighs of the other 50 animals were shaved. Bilateral posterior thigh perforator-based flaps measuring 3x3 cm were elevated. The right-side flaps were sutured back into place and used as controls in all animals. The rats were then randomly divided into five groups according to the procedure performed on the left side. Each group again contained 10 animals. In group I, the flap was rotated 90 degrees in a clockwise direction and sutured into place. In groups II, III, IV and V the rotation were 180, 270, 360 and 720, respectively. One week after flap harvest, viable flap areas were assessed and the percentages of viable flap areas over total flap areas calculated. Microangiography was performed on three flaps in each group. The flaps were examined histopathologically on the basis of edema, congestion, inflammation and ischemia. All control flaps in the groups survived without any problem, as expected, yielding 100%. In the axial group, no study flaps in groups I, II, III or IV exhibited necrosis. In the perforator group, while the study flaps in groups I and II study flaps did not exhibit necrosis, varying degrees of necrosis were observed in group III, IV and V flaps. Statistically, in the perforator group, not only was necrosis seen in the early rotation groups, but mean necrosis areas were also greater than in the axial group. In the second phase of the study, 20 male Wistar rats weighing 200 to 250 g were randomly divided into two groups. In the first group; after the delay procedure was performed, island groin flaps measuring 3x3 cm were elevated and the flap was rotated 720 degrees and sutured into place. In the second group after delay procedure was performed, posterior thigh perforator-based flaps measuring 3x3 cm were elevated and the flap was rotated 720 degrees and sutured into place. With delay procedure some increase were obtained in viable flap areas, but it was not significant statistically. In conclusion; the resistance of axial flap pedicle patern to the torsion is greater than the resistance of perforator pedicle patern and delay phenomen is not an effective method for improving resistance of a flap to torsion .