Topographic anatomy and morphometry of the gracilis muscle related to pelvic transposition flaps: Perineal versus transobturatory approach.

Background: Pelvic dead space following major surgery is commonly addressed by vertical rectus abdominis muscle flaps, omental flaps, or gracilis muscle flaps. The drawback of the gracilis muscle flap is the limited amount of intrapelvic muscle tissue achieved by classic perineal transposition. This proof-of-principle study evaluates the transobturatory transposition of the gracilis muscle flap as an alternative to the perineal approach by revisiting the topographic and vascular anatomy and comparing the achievable intrapelvic muscle length. Methods: In-situ dissections were conducted in body donors ( Results: The main vascular pedicle (mean length: 8.8 cm, mean entry point: 13.3 cm) of the gracilis muscle (mean length: 37.2 cm) originated predominantly from the deep femoral artery. Transobturatory transposition was technically feasible in all specimens, regardless of vascular pedicle pattern, and resulted in significantly increased mean intrapelvic muscle length compared to perineal transposition (17.8 vs. 14.5 cm). Further increase in intrapelvic muscle length was achieved by pedicle mobilization (20.9 vs. 15.5 cm) and incision of the adductor brevis muscle (additional gain of length: 1.0 cm). Conclusions: Gracilis muscle transposition via the obturator foramen is a viable alternative to the perineal route, achieving greater intrapelvic muscle length. The morphometric data on the topography and vasculature of the gracilis muscle provide a valuable basis to use the transobturatory transposition of the gracilis muscle for the reconstruction of pelvic defects.