Comparing the Effects of Pedicle Torsion on Axial or Perforator Flaps; Improving the Perforator Flap Resistance to Pedicle Torsion with Delay Phenomenon Gamze Bektas, MD 1 Ozlenen Ozkan, MD 1 Anı Cinpolat, MD 1 Ibrahim Cumhur Bassorgun, MD 2 Mehmet Akif Ciftcioglu, MD 2 Omer Ozkan, MD 1 1 Department of Plastic, Reconstructive and Aesthetic Surgery, Akdeniz University School of Medicine, Antalya, Turkey 2 Department of Pathology, Akdeniz University School of Medicine, Antalya, Turkey J Reconstr Microsurg 2014;30:531–538. Address for correspondence Omer Ozkan, MD, Department of Plastic, Reconstructive and Aesthetic Surgery, Akdeniz University School of Medicine, Antalya 7090, Turkey (e-mail: omozkan@hotmail.com). With better accuracy in reconstruction and minimal donor-site morbidity, perforator flaps increasingly found acceptance and use in the field of reconstructive surgery. 1 The pedicled perfora- tor flap is now regarded as a valuable tool in reconstructive surgery, but variable degrees of perforator twisting upon flap transposition are frequently encountered intraoperatively. 2 Pedicle twisting is a well-known cause of flap failure, and its detrimental effect was investigated on free flap, axial pattern flap, and perforator flap models. 3–7 Despite the common opinion that perforator flaps are more sensitive to pedicle rotation than axial flaps, there is no comparative study yet on this subject. Our aim in the first part of this study was to compare the resistance to rotation of flap pedicles with an axial pattern or a true perforator pattern equalizing different parameters such as flap size, design, pedicle length, and tension. In the second part of the study, we investigated whether surgical delay improves perforator flap viability in cases where the flap pedicle needs to be rotated. Surgical delay is described as the disruption of blood circulation by surgical Keywords ► perforator flap ► torsion ► delay phenomenon Abstract Background The torsion of the flap’s pedicle is one of the most common conditions causing vascular compromise. 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 for improving perforator flap resistance to pedicle torsion. Methods In the first phase, 90 male Wistar rats were randomly divided into two groups: perforator and axial. Bilateral groin flaps were elevated in the axial group and bilateral posterior thigh perforator-based flaps were elevated in the perforator group. Viable flap areas were compared at 90, 180, 270, 360, and 720 degrees of pedicle rotation. Microangiographic and histopathological studies were performed. Result As a result, necrosis was seen following earlier rotation in the perforator group and viable flap areas were also lower. In the second phase, after delay procedure, the perforator flaps were exposed to 270, 360, and 720 degrees of pedicle rotation. With the delay procedure, no significant difference in viable flap areas was observed. Conclusion In conclusion, the resistance to torsion of the axial flap pedicle pattern was greater than that of the perforator pedicle pattern, and the delay procedure was not an effective method for improving flap resistance to torsion. received December 4, 2012 accepted after revision August 13, 2013 published online March 3, 2014 Copyright © 2014 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662. DOI http://dx.doi.org/ 10.1055/s-0033-1357281. ISSN 0743-684X. Original Article 531 Downloaded by: IP-Proxy CONSORTIUM:ANKOSLICENSE (Cukurova_University), Çukurova University. Copyrighted material.