This technical note describes the harvesting and insetting of a chimeric anterolateral thigh (ALT) flap to reconstruct a through and through cheek defect. Two perforators originating from the lateral circumflex femoral system that joined to the same mother vascular source were identified. Two separate skin paddles based on the perforators were designed and appropriately inset to repair the mucosal lining and the cheek skin. Careful harvesting and insetting of the chimeric ALT flap ensures a good cosmetic and reconstructive effect in the reconstruction of the through and through cheek defect.
Reconstruction of through and through buccal defects after ablation of head and neck cancer is a challenge for the plastic surgeons, that requires three-dimensional restoration of the missing tissue. The cosmetic effect has to be considered, and both the oral mucosal lining and cheek skin need to be reconstructed simultaneously. The excision of the mouth commissure makes the procedure more complicated. Reconstruction using a pedicled musculocutaneous flap or folded free flap is not optimal. These flaps are too bulky for reconstruction of both sides at the same time . Although double free flaps can be easily inset and are convenient for these complex defects, harvesting the two flaps and anastomosing two pairs of pedicles is time consuming and complicated .
The chimeric anterolateral thigh (ALT) flap was developed by Koshima & Hallock . It is a combined composite free flap using the lateral circumflex femoral system that has separate skin paddles with different perforators physically attached to the same mother vascular source . The features of this flap made it possible to repair the oral mucosal lining and cheek skin simultaneously with one anastomosis of pedicle. Huang et al. reported their experiences in reconstructing through and through cheek defects involving the oral commissure using chimeric ALT flaps , but the harvesting and insetting of the chimeric ALT flap was not described in detail. In this technical note, the authors describe their experience in the surgical reconstructive techniques of the through and through cheek defect using a chimeric ALT flap.
Localization of the perforators
The patient was in the supine position with a slight medial rotation of the ipsilateral thigh. The ilio-patellar line and the body surface projection line of the descending branch of the lateral circumflex femoral artery were marked. An incision line was designed along the interior side of the ilio-patellar line. The skin and fascia lata were incised. The skin flap was developed to the lateral side of the rectus femoris muscle under the fascia lata. The flap was pulled by three suture stitches to expose the interface between the flap and the vastus lateralis muscle. Mosquito haemostatic forceps were used to delicately dissect and explore the perforators penetrating the fascia lata along the interface. Two perforators were identified and the distance between them was measured ( Fig. 1 ).
Harvesting and preparing the chimeric ALT flap
After the localization of two perforators, the rectus femoris muscle was retracted internally to expose the descending branch of the lateral circumflex femoral artery. Dissection of the perforators was started by cautiously dividing the muscle fibres covering the perforator vessels bit by bit until the conjunction points between the perforators and the descending branch were met. A thin muscular or facial sleeve was well preserved around the perforators to protect them from convulsion and accidental injury. The two perforators were dissected. The descending branch was ligated and divided after the ramification of perforators. The dissection was continued centripetally along both sides of the descending branch to the main trunk of the lateral circumflex femoral system. The skin flap was incised after freeing the pedicle. Two skin islands based on the two separate perforators were designed and split according to the size of the inner and outer defects. The chimeric ALT flap with two skin islands based on two separate perforators was formed ( Fig. 2 ).