Manual extrusion of fat granules for primary thinning of a bulky flap

Primary thinning of bulky flaps in high-body mass index patients remain a significant challenge in reconstructive microsurgery. Aggressive defatting risks compromising the linking vessels between the subdermal and suprafascial plexuses, leading to flap marginal necrosis. Consequently, one-stage thinning of large, fatty flaps is generally discouraged. A new three-step technique was applied in eight consecutive patients undergoing free flap transplantations between August and October 2025. The procedure consisted of: suprafascial flap elevation; radial fasciotomy (incision of the superficial fascia) around perforators; and manual extrusion of fat granules, performable before or after pedicle division. Flaps were thinned to a target fat layer thickness of <0.5 cm. Operative time for flap thinning, intraoperative vasospasm (>5 minutes), and postoperative complications were assessed. All eight flaps were successfully thinned to an ultra-thin state (<0.5 cm) within 20 minutes. No vascular branches required sacrifice during manual extrusion. No lasting vasospasm or postoperative complications (e.g., vascular compromise, partial necrosis, or skin ecchymosis) occurred. All flaps survived completely. This novel approach enables safe, efficient, single-stage flap thinning while preserving sensation, even in obese patients. It represents a significant advance that merits further validation through larger comparative studies. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.