Modification of pedicle lengthening through perforator transposition in free anterolateral thigh flaps with pedicle size discrepancy: A case report.

In spite of thorough presurgical planning, emergency situations requiring longer pedicle length may arise during anterolateral thigh (ALT) free flap surgeries. While performing vessel graft for pedicle lengthening, discrepancy may occur because of a certain genetic predisposition or vascular variation at the anastomosis site of the graft vessel and the flap pedicle. A 76-year-old male patient with neurofibromatosis type I had a 15 x 10 cm defect, which was caused by radical excision of a malignant peripheral nerve sheath tumor on his back. A 15 x 10 cm sized free ALT flap was obtained. The distance between the recipient vessels and the defect area was 20 cm. The diameters of vessels in the harvested flap were as follows: proximal end of the descending branch of the lateral circumflex femoral artery (LCFA)-artery/vein: 3.0/2.5 mm, distal end of the descending branch of the LCFA-artery/vein: 1.0/1.0 mm, and perforator in the ALT flap-artery/vein: 0.8/1.0 mm. The conventional method requires transfer of the distal portion of the LCFA (below the bifurcation) which mandates us to perform anastomoses with a vessel diameter discrepancy of 2 mm. As an alternative, a bifurcating perforator-including flap was transposed to the most distal part of the descending branch of the LCFA. An ALT flap with a pedicle having a total length of 20 cm was constructed. The flap survived without any complications. This technique may provide an option for resolving size discrepancy between the graft vessel and the ALT pedicle.