Redefining the Anatomic Boundaries for Safe Dissection of the Skin Paddle in Free Gracilis Myofasciocutaneous Flaps—An Indocyanine Green Cadaveric Study

Abstract

There is no financial information to disclose. Anatomical studies of the gracilis myocutaneous flap describe the skin paddle to be limited to the proximal two-thirds overlying the gracilis muscle. This study describes the area of skin that can be safely harvested with a free extended gracilis muscle flap on a single vascular dominant pedicle with wide fascia harvest. The skin paddle is designed overlying the length of the gracilis muscle and dissection is carried down to the deep fascia. The deep fascia is then harvested wider than the margins of the skin paddle circumferentially, from the anteromedial fascia of the thigh to the posterior edge of the gracilis with its investing fascial sleeve. The gracilis and overlying skin are kept in continuity to preserve distal skin paddle perfusion. The deep fascia and skin paddle are sutured together to prevent shearing injury of the fasciocutaneous perforating branches. Using a cadaveric model, 9 free flaps were evaluated using indocyanine green (ICG) with cadaveric blood as the carrier. The ICG was injected into the single vascular dominant pedicle, the deep branch of the medial circumflex artery. These extended gracilis free flaps were compared with the standard gracilis free flap (investing fascia only) with the same sized skin paddle via the same injection technique. Imaging was performed using the SPY Elite and SPY-PHI (Stryker). In a cadaveric model, the extended gracilis free flap exhibited ICG perfusion to a 40 x 21-cm skin paddle, whereas the standard gracilis skin paddle demonstrated ICG perfusion to an area of 22 x 11 cm (Figure 71-1). The extended gracilis free flap demonstrated perfusion of 587 cm2 more surface area, equating to over 330% greater skin surface coverage than the standard gracilis myocutaneous free flap. •Wide dissection of the deep fascia beyond the margins of the skin paddle can improve viability of the distal skin overlying the gracilis myocutaneous flap (Figure 71-2).•The extended myofasciocutaneous gracilis free flap is useful in patients for whom free functional muscle transfer and additional skin coverage are required.•Wide fascial dissection of the extended gracilis free flap can increase viable skin overlying the gracilis myocutaneous flap by over 330% of the standard surface area.•ICG can be a valuable tool to evaluate perforasomes in cadaveric studies.Figure 71-2Myofasciocutaneous gracilis free flap zone of skin perfusion.View Large Image Figure ViewerDownload Hi-res image Download (PPT)