Applied anatomy of the latissimus dorsi free flap for refinement in one-stage facial reanimation

Abstract

The face can be reanimated after long-term paralysis by free microneurovascular tissue transfer. Flaps from gracilis and pectoralis minor usually require a two-stage procedure with a cross-face nerve graft. Latissimus dorsi has a much longer muscular nerve, the thoracodorsal nerve, which could avoid the need for a second cross-face nerve graft. Our hypothesis is that the neurovascular pedicles of small segments of latissimus dorsi would be long enough to reach the opposite side of the face and to provide a reliable blood and nerve supply to the flaps. To test this hypothesis the thoracodorsal pedicle and its primary branches were dissected in eleven embalmed cadavers. The segmental vessels and nerves were then traced in a series of simulated flaps approximately 8-10 cm × 2-3 cm by micro-dissection, tissue clearing and histology. The thoracodorsal pedicle is 10-14 cm long to where it enters the muscle, and with intra-muscular dissection small chimeric muscle segments 8-10 cm × 2-3 cm can be raised with a clearly defined neurovascular supply. Using micro-dissection the neurovascular pedicle can be lengthened to reach across the face. Segmental arteries and nerves extended to the distal end of all the flaps examined. Artery, vein and nerve run together and are of substantial diameter. Small muscle segments of latissimus dorsi can be raised on long neurovascular pedicles. The vessels and nerves are substantial and the likelihood of surgical complications such as flap necrosis and functional disuse on transplantation appear low. Although in our opinion the use of cross-face nerve grafts and transfer of smaller muscle flaps remains the gold standard in facial reanimation in straightforward cases, the micro-dissected latissimus dorsi flap is a useful option in complex cases of facial reanimation. Facial reanimation using micro-dissected segments of latissimus dorsi has been performed in four complex cases of facial paralysis.