Detailed clinical anatomy for the anterolateral (anteromedial) thigh flap

Anatomical variations of the descending branch of the lateral circumflex femoral system were investigated in 164 lower extremities out of 159 clinical cases. The detailed anatomy of the lateral circumflex femoral vessels was observed during surgery. The relationship between the main branches and the cutaneous perforators is also described in this paper. Three hundred and ninety-eight perforators were observed on the anterolateral aspect of the thigh. Of these, 336 (84.4%) perforators were musculocutaneous, and 62 (15.6%) were septocutaneous. In contrast, 68 perforators were observed on the anteromedial aspect of the thigh. Of these, 58 (85.3%) perforators were septocutaneous, and 10 (14.5%) were musculocutaneous. Absence of the descending branch occurred in 19 cases (11.6%). It was replaced by the muscle branch of the vastus lateralis. The authors classified the anatomical variations of the descending branch of the lateral circumflex femoral artery into the following six types. Type A in which the descending branch ran inferolateraly through the intermuscular septum between the rectus femoris and vastus intermedius accounted for 67.1% of the thighs (110 thighs). Nine thighs (5.5%) belonged to type B in which a small descending branch ran distally behind the anterior edge of the vastus lateralis giving off the small muscle branches, and the musculocutaneous perforator arose from a large muscle branch of the vastus lateralis which passes distally through this muscle. Type C in which the descending branch was absent and was replaced by the large muscle branch of the vastus lateralis accounted for 11.6% of the thighs (19 thighs). Type D in which the double descending branches could be seen accounted for 6.1% (10 thighs). Type E in which the medial descending branch ran intermediary giving off the major muscle branch of the rectus femoris accounted for 4.9% of the thighs (8 thighs). The residual 8 thighs (4.9%) were Type F in which the medial descending branch ran laterally after giving off a medial perforator and extended to the vastus lateralis, as with the lateral descending branch. The authors also describe the single-pedicle double-flap method, flow-through anastomosis, turbo-charged (mosaic) flap and double-pedicled flap utilizing derivative branches and distal run-off of the descending branch of the lateral circumflex femoral artery. At least one perforator could always be observed on the anterolateral aspect of the thigh in all types. Therefore, the anterolateral thigh flap could be elevated in all cases even when there was no descending branch.