Twelve hours after a free anterolateral thigh flap transfer for a mandibular reconstruction, the flap appears swollen and dusky blue. A 21-gauge needle prick into the flap yields dark blood that bleeds briskly. The most likely diagnosis is:

• A Venous outflow obstruction ✓
• B Arterial inflow occlusion
• C Normal postoperative venous congestion resolving spontaneously
• D Partial flap necrosis of the distal portion

Explanation

Venous congestion presents with a swollen, bluish, turgid flap and brisk dark bleeding on needle prick, caused by outflow thrombosis while arterial inflow persists. Arterial occlusion instead produces a pale, cool, flat flap that does not bleed on prick. Venous thrombosis is the commonest cause of early free flap failure and demands immediate return to theatre since salvage rates fall sharply beyond a few hours.

Reference: Grabb and Smith's Plastic Surgery, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.